Diagnostic Value of Hematological Inflammatory Indices (NLR, PLR, HPR) in Thrombotic Thrombocytopenic Purpura: A Case-Control Study

Abstract

Background and Aim

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening and rare thrombotic microangiopathy (TMA) described as severe thrombocytopenia, microangiopathic hemolytic anemia, and ischemic end-organ injury because of microvascular platelet-rich thrombi. Recent findings show inflammatory conditions such as infection and surgery can be triggers for TTP onset. The aim of this study was to evaluate the diagnostic performance and clinical relevance of hematological inflammatory indices (NLR, PLR, and HPR) in patients with thrombotic thrombocytopenic purpura compared with healthy controls.

Methods

This case-control study was conducted on 114 TTP patients (90 female and 24 male) and 115 healthy controls from January 2010 to December 2022 in Imam Reza Hospital, Mashhad, Iran. Immune cell counts, inflammatory parameters, and hematological markers including NLR, PLR, and HPR were calculated using the complete blood count at the time of diagnosis and after the treatment. Statistical analyses were conducted by MedCalc, IBM SPSS Statistics version 26 and GraphPad Prism version 9.5.0.

Result

The result showed that at the time of admission, systemic (70.2%), bleeding (40.4%), and renal (41.2%) symptoms were the most frequent, whereas a lower prevalence of neurological (22.8%) signs and symptoms was observed. White blood cell (WBC) and neutrophil counts were higher in TTP patients (WBC: p< 0.001, neutrophil: p<0.001), and conversely, platelet and lymphocyte counts were higher in the control group compared to TTP patients (platelets: p<0.001, lymphocytes: p<0.001). The indices analysis between the two groups revealed that NLR and HPR were significantly increased in TTP patients (p<0.001), but PLR was significantly reduced in TTP patients (with the mean platelet count of 62.09 ± 55.37× 10⁹/L) compared to the control group (with the mean platelet count of 236.82 ± 43.19× 10⁹/L) (p<0.001).

Conclusion

Elevated NLR and HPR, together with decreased PLR, were associated with TTP in this cohort and may offer adjunctive diagnostic value alongside established clinical criteria. Confirmation in larger, prospective studies will be important to define their place in routine practice.

1. Introduction

Thrombotic microangiopathies (TMAs) constitute a heterogeneous group of disorders characterized by distinct pathophysiologies, resulting in occlusive microvascular or macrovascular thrombosis. They are characterized by microangiopathic hemolytic anemia, thrombocytopenia, and end-organ ischemia, and are associated with significant morbidity and mortality. ¹ Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially life-threatening thrombotic microangiopathy. It is characterized by the formation of thrombi in the microvasculature, which leads to microangiopathic hemolytic anemia, severe thrombocytopenia, and organ damage. ² Among triggers of this disease are pregnancy and inflammatory conditions such as surgery and infection. Inflammation is known to be correlated with oxidative stress and therefore has the ability to increase platelet adhesion via ADAMTS13 or VWF. Some studies although inconclusively suggest that Neutrophil products may contribute to pathophysiology of TTP by inactivating ADAMTS13. ³

TTP is classified as congenital (cTTP) or immune-mediated/acquired (iTTP). cTTP, also known as Upshaw-Schulman syndrome, results from biallelic ADAMTS13 mutations and persistent severe deficiency (<10%). ⁴ iTTP arises from autoantibody-mediated ADAMTS13 deficiency,^4,5 leading to accumulation of ultra-large VWF multimers, platelet-rich thrombi, and ischemic organ injury. ⁶ Acquired TTP accounts for ≥95% of cases, predominantly in adults, while cTTP is rare (<5%). ⁷ The annual incidence of iTTP is 1.5–6 per million, with a female predominance (2:1–3.5:1) and onset typically in the third to fifth decades.^8-11 Inherited ADAMTS13 deficiency occurs in 3–5% of patients,^10-12 with cTTP prevalence estimated at 0.5–2 per million. ¹³ Early symptoms are nonspecific (fatigue, confusion, headache, nausea), but progress to organ ischemia. Neurological manifestations occur in ∼60% of patients, gastrointestinal ischemia in 35%, myocardial ischemia in 25%, and renal injury is common.^14-18 Acute TTP typically presents with profound thrombocytopenia (<30×10⁹/L) and microangiopathic hemolytic anemia, with schistocytes on peripheral smear. ¹⁹ Hemolysis markers include undetectable haptoglobin, elevated reticulocytes, bilirubin, and LDH. ²⁰ Diagnosis is confirmed by ADAMTS13 activity <10%.^21,22

Complete blood count (CBC) remains a simple, widely available diagnostic tool. Recently, leukocyte and platelet ratios such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), hemoglobin-to-platelet ratio (HPR), and monocyte-to-lymphocyte ratio (MLR) have gained importance. ²³ The biological rationale for evaluating these specific ratios in TTP lies in the systemic inflammatory response and the vascular thrombotic burden inherent to the disease’s pathophysiology. Previous studies in thrombotic and vascular disorders have demonstrated that CBC-derived inflammatory ratios mirror disease severity and microvascular compromise. For example, Songur et al showed that PLR could predict amputation risk in critical limb ischemia (CLI), reflecting the complex relationship between platelet activation and vascular occlusion. ²⁴ Similarly, Lafci et al showed that admission NLR was independently associated with in-hospital mortality in acute type I aortic dissection, underscoring the prognostic value of neutrophil-driven inflammation in acute thrombotic state. ²⁵ As TTP involves both extensive microvascular platelet-rich thrombosis and inflammation-driven triggers—such as infection and surgery—these indices may offer incremental diagnostic and prognostic information beyond standard laboratory parameters. Also, these indices serve as prognostic markers in solid tumors,^26-32 hematological malignancies including MM, HL, FL, MCL, DLBCL,^33-37 and select leukemias/myeloproliferative disorders. Thus, they may also aid in TTP prognosis and treatment selection. The objective of this retrospective study is to assess PLR, NLR, and HPR in TTP patients compared to controls, and to examine correlations with hospitalization duration, therapeutic approaches, and clinical symptoms.

2. Materials and Methods

2.1 Study Subjects and Patients’ Characteristics

In this case-control study, we conducted an analysis of the data of 114 patients diagnosed with TTP from January 2010 to December 2022 at Imam Reza Hospital of the University of Medical Sciences (MUMS), Mashhad, Iran. The definition of TTP was adopted from the 2023 British Society for Hematology Guideline. ³⁸ TTP patients included 90 females (78.95%) and 24 males (21.05%), and the control group consisted of 115 healthy individuals (male: 40.86%, female: 59.14%) who were referred to the same hospital for their check-up tests. The control group was composed of individuals who were closely similar to the patient group in terms of age and gender. To provide a conservative and clinically challenging comparison, control subjects were deliberately selected with platelet counts falling within the low-to-mid normal range. This approach was adopted to ensure that any observed differences in PLR reflected genuine disease-related immune-thrombotic dysregulation rather than simply contrasting profoundly thrombocytopenic patients with individuals at the upper end of the normal platelet spectrum. All control group members had no history of chronic disease and TTP-related clinical or laboratory symptoms, including thrombocytopenia (platelet count less than 100 × 10⁹ platelets/L), bleeding, systemic inflammation, erythrocyte fragmentation (schistocyte), hemolysis parameter, and thrombosis.

2.2 Ethics Approval

The research procedures were carried out on participants under the ethical standards set by the local ethics committee of Mashhad University of Medical Sciences (IR. MUMS.FHMPM.REC.1401.031) as well as the 1964 Helsinki Declaration. Furthermore, all participants in this study or their family members responsible were informed of the use of their data for this study and provided informed consent.

2.3 Inclusion & Exclusion Criteria

Inclusion criteria include the following: thrombocytopenia (defined as a platelet count of less than 150 × 10⁹ platelets/L) without evidence of bone marrow involvement or HIV infection, microangiopathic hemolytic anemia (MAHA), increased lactate dehydrogenase (LDH, with a value greater than 1.5 times the upper limit of normal), the presence of bleeding signs (such as purpura, petechiae, ecchymoses, and hematomas) and the presence or absence of ischemic organ damage. The comprehensiveness of the clinical profile and the quality of the laboratory and clinical data were also considered.

The exclusion criteria for this present study are as follows: Patients with a previous history of hemolytic uremic syndrome (HUS), catastrophic anti-phospholipid syndrome, hemolysis, elevated liver enzymes, and low platelets syndrome (HELLP syndrome), pre-eclampsia, Evans syndrome, sepsis, disseminated intravascular coagulation (DIC), systemic lupus erythematosus (SLE), Behçet’s disease (BD), rheumatoid arthritis (RA), ankylosing spondylitis (AS), immune thrombocytopenic purpura (ITP), smokers, patients taking immunosuppressive drugs, and thrombotic microangiopathies secondary to cancer.

2.4 Inflammatory & Hematological Parameters

The data about the patients’ profiles, including their demographic information, such as age, gender, medical history, and blood cell count (platelets, white blood cells, neutrophils, and lymphocytes), as well as other hematological parameters such as hematocrit (Hct) and hemoglobin (Hb) levels, were extracted from the hospital archives department using predesigned checklists. This was done at the time of diagnosis and after the treatment. Additionally, hematological inflammatory parameters, including NLR, PLR, and the HPR, were calculated and analyzed in two distinct time periods: before and after the implementation of the therapeutic approaches. These data were collected and analyzed for the control group under identical conditions as those applied to the experimental group. In addition, other inflammatory tests, including CRP and ESR, were measured, and the association between hospitalization, survival status, CRP, and ESR (at the time of diagnosis and after treatment) was investigated.

2.5 Clinical Findings & Therapeutic Approaches

All clinical findings related to TTP patients were subjected to evaluation and comparison with hematological parameters. These clinical findings in TTP patients were classified into five major categories, with explicit diagnostic definitions as follows: systemic (abdominal pain, fatigue, fever, headache, jaundice, vomiting), bleeding (defined as the presence of purpura, petechiae, ecchymoses, hematomas, gum bleeding, respiratory tract bleeding, gastrointestinal bleeding, macroscopic hematuria, or menorrhagia), renal (defined as acute renal failure, anuria, need for dialysis, elevated serum creatinine (>1.3 mg/dL), hemoglobinuria, proteinuria, or oliguria), neurological (defined as coma, focal sensory or motor deficit, seizures, stroke, personality and behavior changes, or transitory ischemic attack) and cardiovascular signs and symptoms (defined as acute coronary syndrome, arrhythmias, or electrocardiographic (ECG) abnormalities). The medical procedures and therapeutic agents prescribed for patients with TTP were extracted from their profiles. These findings included the prescription of plasma exchange, corticosteroids, rituximab, cyclosporine, azathioprine, prednisolone, and intravenous immune globulin therapy (IVIG). Furthermore, surgical procedures such as splenectomy are used. Because treatment assignment was non-randomized and determined by the treating clinicians based on disease severity and institutional protocols, associations between treatment modalities and inflammatory indices should be interpreted with caution. The duration of hospitalization in patients was measured and the correlation between clinical symptoms in patients, the treatment strategies used, and the length of hospitalization was analyzed.

2.6 Statistical Analysis

Statistical analyses were conducted by IBM SPSS software version 26 and GraphPad Prism version 9.5.0. The analyses were conducted on two principal groups: the case group and the control group. The case group was subsequently divided into two distinct subgroups: before treatment (at the time of diagnosis) and after treatment. Categorical variables (nominal or ordinal scale) were analyzed as the frequency with percentages, while continuous variables were described using mean ± standard deviation (mean ± SD). The normality of data was assessed using the Kolmogorov–Smirnov test. Associations between different indices on continuous scales were evaluated using Pearson or Spearman correlation tests. The nonparametric Mann–Whitney U and Kruskal–Wallis H tests were employed to compare variables between the control group and TTP patients. All tests were two-sided, and a p-value of less than 0.05 (p-value <0.05) was considered statistically significant for all analyses. Given the exploratory nature of this study and the relatively large number of comparisons performed between clinical findings, treatments, and hematological parameters, findings with p-values close to the 0.05 threshold should be interpreted with heightened caution due to the potential inflation of Type I error. Although formal correction methods such as Bonferroni or false discovery rate (FDR) adjustment were not applied in this primarily descriptive analysis, their relevance is acknowledged, and future confirmatory studies should incorporate appropriate multiplicity adjustments.

2.7 Assessment of Sensitivity and Specificity

Firstly, the calculation of inflammatory indices (NLR, PLR, and HPR) was undertaken. Subsequently, the sensitivity and specificity of the aforementioned indices were evaluated using the receiver operating characteristic (ROC) curve. The cut-off and the area below the curve were subjected to separate analyses in order to evaluate the sensitivity and specificity of different potential predictors of inflammatory indices. The results of the ROC curve were subjected to analysis using the MedCalc 15.0 software. The optimal cut-off point values were obtained by maximizing Youden’s index, a method that mitigates overfitting by simultaneously optimizing sensitivity and specificity rather than maximizing either in isolation. Once the predictive cut-off thresholds of hematological ratios had been determined, the sensitivity and specificity of each index were categorized into one of the following classes according to the traditional academic point system: more than 90%: excellent (class I), 80%–90%: good (class II), 70%–80%: acceptable (class III), 60%–70%: poor (class IV), 50%–60% or less than 50%: fail (class V). However, it is acknowledged that performance metrics derived from a single retrospective cohort without external validation are susceptible to over-optimism, and the reported cut-off values should be regarded as preliminary and cohort-specific.

3. Results

The case-control study comprised 229 participants, with nearly equal distribution between the two groups: patients with TTP (n=114; 49.7%) and control subjects (n=115; 50.3%). Among the TTP patients, 90 (78.95%) were female and 24 (21.05%) were male. The control group consisted of 68 females (59.14%) and 47 males (40.86%) (Table 1). Key hematological differences between groups are summarized below, with full details provided in Table 2.

Table 1.

Demographic Information of TTP Patients and Control Group

Characteristics		TTP patients (N = 114)	Control group (N = 115)	Effect size	p-Value
Gender	Male, n (%)	24 (21.05)	47 (40.86)	0.214	0.002
	Female, n (%)	90 (78.95)	68 (59.14)
Blood Group	O, n (%)	43 (37.7)	-	-	-
	A, n (%)	40 (35.1)	-
	B, n (%)	23 (20.2)	-
	AB, n (%)	8 (7.0)	-

Note. Analysis in this table was performed using χ2 (for gender) and Wilcoxon–Mann–Whitney tests. Abbreviations: TTP, Thrombotic thrombocytopenic.

Table 2.

Hematological and Inflammatory Parameters of TTP Patients and Control Group

Characteristics	TTP patients (N = 114)	Control group (N = 115)	Effect size	p-Value
Red blood cell × 1012/L	3.11±0.78	4.90±0.37	0.811	<0.001
White blood cell × 109/L	10.032±5.150	7.008±1.479	0.334	<0.001
Neutrophils × 109/L (ANC)	7.79±4.68	3.92±0.86	0.512	<0.001
Lymphocytes × 109/L (ALC)	1.76±2.29	2.47±0.56	0.562	<0.001
Platelet × 109/L	62.09±55.37	236.82±43.19	0.830	<0.001
Hct, mean ± SD (%)	26.87±6.78	39.83±3.05	0.794	<0.001
Hb, mean ± SD (g/dL)	8.85±2.42	13.39±1.29	0.784	<0.001
HPR, mean ± SD	3.84±4.93	0.58±0.13	0.702	<0.001
NLR, mean ± SD	6.57±5.06	1.59±0.17	0.733	<0.001
PLR, mean ± SD	63.77±94.92	98.81±22.80	0.503	<0.001
LDH, IU/L	1642.22±1635.51	169.60±118.53	0.338	<0.001
CRP, mg/L	53.91±75.95	5.22±2.47	0.568	<0.001
ESR, mm/h	44.75±30.24	12.20±4.51	0.636	<0.001
PT, second	15.11±7.03	12.12±0.25	0.578	<0.001
INR	1.30±0.65	1.02±0.06	0.457	<0.001
PTT, second	42.68±39.39	25.87±0.59	0.518	<0.001
Schistocytes, % of positive samples, n (%)	100 (87.7)	0 (0)	-	-

Abbreviations: ANC, absolute neutrophil count, ALC, absolute lymphocyte count, Hb, hemoglobin; Hct, hematocrit; HPR, hemoglobin‐to‐platelet ratio; TTP, Thrombotic thrombocytopenic purpura; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet‐to‐lymphocyte ratio; CRP, C-reactive protein; ESR, Erythrocyte sedimentation rate; PT, Prothrombin time; INR, International normalized ratio; PTT, Partial thromboplastin time; Retic, Reticulocyte. Data are reported as effect size r (p-value), where r = Z/√N.

3.1 Primary Findings: Hematological Parameters and Inflammatory Indices

Statistical analysis showed significant differences in cell counts and other hematological markers between TTP patients and the control group (Table 2). Specifically, TTP patients had higher WBC and neutrophil counts (WBC: P < 0.001; Neutrophil: P < 0.001), while platelet and lymphocyte counts were higher in the control group (Platelets: P < 0.001; Lymphocytes: P < 0.001). RBC count, Hct, and Hb levels were all significantly lower in TTP patients (all P < 0.001). Lactate dehydrogenase (LDH) levels were markedly elevated in TTP patients (1642.22 ± 1635.51 IU/L) compared to controls (169.60 ± 118.53 IU/L; P < 0.001). CRP (53.91 ± 75.95 mg/L) and ESR (44.75 ± 30.24 mm/h) were also significantly higher in the TTP group (both P < 0.001). A significant prolongation of PT and PTT was observed in TTP patients compared to controls (P < 0.001), consistent with consumption coagulopathy. The distribution of hematological indices in TTP patients is presented in Table 3.

Table 3.

Distribution of Hematological Indices in the TTP Patient Group

Variables	Frequency (%)
Hb (g/dL) in female patients	<12	>12
	92.2	7.8
Hb (g/dL) in male patients	<13.5	>13.5
	91.7	8.3
WBC (Cells/µL)	<11000	>11000
	64.9	35.1
PLT (/µL)	<150000	>150000
	92.1	7.9
CRP (mg/L)	<10	>10
	45.3	54.7
ESR (mm/hr) in female patients	<20	>20
	17.2	82.8
ESR (mm/hr) in male patients	<15	>15
	31.6	68.4
Retic Count (%)	<2.5	>2.5
	40	60
LDH (U/L)	<280	>280
	0.9	99.1
PT (Second)	<13.5	>13.5
	47.9	52.1
PTT (Second)	<35	>35
	73	27

Abbreviations: Hb, hemoglobin; PLT, Platelet; CRP, C-reactive protein; ESR, Erythrocyte sedimentation rate; LDH, Lactate dehydrogenase; PT, Prothrombin time; PTT, Partial thromboplastin time; Retic, Reticulocyte.

3.2 Diagnostic Performance (ROC Analysis)

The comparison of the area under the receiver operating characteristic curve (AUROC) identified NLR, PLR, and HPR as informative markers for distinguishing TTP patients from healthy controls (Table 4 and Figure 1). The optimal cut-off values were: NLR > 1.96 (AUC: 0.925, 95% CI: 0.882–0.955, sensitivity: 91.2%, specificity: 100%), PLR ≤ 68.20 (AUC: 0.791, 95% CI: 0.733–0.842, sensitivity: 69.3%, specificity: 94.8%), and HPR > 0.85 (AUC: 0.906, 95% CI: 0.861–0.941, sensitivity: 79.8%, specificity: 98.3%). Although the specificity for NLR reached 100% in this cohort, this likely reflects clear separation between the patient and control populations studied and underscores the need for external validation in independent cohorts before these thresholds can be recommended for routine clinical application.

Table 4.

Clinical Symptoms in TTP Patients at the Time of Admission

Clinical symptoms (at the time of diagnosis)	TTP patients with symptoms, n (%)
Skin symptoms 1	70 (61.4)
Renal symptoms 3	47 (41.2)
Neurological symptoms 2	26 (22.8)
Systemic symptoms 4	80 (70.2)
Bleeding symptoms 5	46 (40.4)
Fever	55 (48.2)

Note. Clinical signs and symptoms were categorized as follows.

¹Skin symptoms: purpura, Petechiae, and Ecchymosis.

²Neurological: stroke, seizures, coma, personality change, focal neurological signs, and transitory ischemic attack.

³Renal: acute renal failure, anuria, need for dialysis, creatinine > 1.3 mg/dL, hemoglobinuria, proteinuria, and oliguria.

⁴Systemic: fatigue, fever, abdominal pain, headache, jaundice, vomiting.

⁵Bleeding: hematuria, meno-metrorrhagia, mucosal bleeding, and gastrointestinal bleeding.

Figure 1.

Receiver operating characteristic curve, sensitivity, and specificity of neutrophil‐to‐lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and hemoglobin‐to‐platelet ratio (HPR) in the thrombotic thrombocytopenic purpura patients

3.3 Secondary Findings: Clinical Associations and Hospitalization

Clinical examinations revealed that skin signs, including petechiae, purpura, and ecchymosis, were present in 61.4% (n=70) of TTP patients. Additional clinical symptoms are summarized in Table 5. Systemic symptoms (70.2%), bleeding (40.4%), and renal involvement (41.2%) were the most frequent presentations, while neurological manifestations were observed in 22.8% of patients.

Table 5.

Sensitivity and Specificity of Cellular/Hematological Indices in TTP Patients

Indices	AUC	Cut-Off (criterion)	Standard error a	95% CI b	Sensitivity (%)	Specificity (%)
NLR	0.925	> 1.96	0.0241	0.882 to 0.955	91.2	100
PLR	0.791	≤ 68.20	0.0340	0.733 to 0.842	69.3	94.8
HPR	0.906	> 0.85	0.0236	0.861 to 0.941	79.80	98.3

Abbreviation: AUC; area under the curve; CI: confidence interval; NLR: neutrophil-to-lymphocyte ratio; PLR: platelet-to-lymphocyte ratio; HPR: hemoglobin-to-platelet ratio.

^aDeLonget al., 1988.

^bBinomial exact.

Table 6 details the associations between hospitalization, hematological parameters, and selected clinical symptoms. Significant associations were found between the presence of purpura and hospitalization (P = 0.047), PLT (P = 0.004), and HPR (P = 0.007); ecchymosis was significantly associated with hospitalization (P = 0.014); and bleeding was associated with prolonged hospitalization (P = 0.006). Fever showed significant associations with PLT (P = 0.033) and PLR (P = 0.008). Other clinical symptoms, including petechiae and bruising, did not reach statistical significance. The average duration of hospitalization was 28.51 ± 21.90 days (range: 1–87 days). Lower Hb levels were also associated with prolonged hospitalization (P < 0.001).

Table 6.

Association Between Hospitalization, Hematological Parameters, and Clinical Symptoms of TTP Patients

Clinical symptoms (at the time of diagnosis)	Effect size (p-value) a
	Hospitalization	Plt	PLR	NLR	HPR
		At the time of diagnosis
Bleeding	0.264 (0.006)*	0.028 (0.759)	0.014 (0.878)	0.088 (0.345)	0.021 (0.817)
Neurological	0.005 (0.949)	0.001 (0.992)	0.058 (0.532)	0.133 (0.153)	0.043 (0.639)
Renal	0.018 (0.843)	0.286 (0.002)*	0.378 (<0.001)*	0.308 (0.001)*	0.276 (0.003)*
Thrombocytopenia	0.054 (0.566)	0.381 (<0.001)*	0.348 (<0.001)*	0.003 (0.970)	0.358 (<0.001)*
Systemic	0.509 (<0.001)*	0.225 (0.016)*	0.216 (0.021)*	0.020 (0.831)	0.192 (0.040)*
Purpura	0.192 (0.047)*	0.268 (0.004)*	0.183 (0.050)*	0.065 (0.485)	0.254 (0.007)*
Petechiae	0.044 (0.645)	0.153 (0.102)	0.129 (0.166)	0.042 (0.649)	0.137 (0.141)
Ecchymosis	0.239 (0.014)*	0.139 (0.137)	0.136 (0.145)	0.015 (0.872)	0.097 (0.297)
Fever	0.143 (0.139)	0.199 (0.033)*	0.248 (0.008)*	0.162 (0.083)	0.209 (0.025)*
Hospitalization, mean ± SD (days)	28.51±21.90, range (1–87)

Note. The analysis for clinical symptoms was performed based on the Wilcoxon–Mann–Whitney test. Abbreviations: Hb, hemoglobin; Hct, hematocrit; HPR, hemoglobin‐to‐platelet ratio; TTP, Thrombotic thrombocytopenic purpura; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet‐to‐lymphocyte ratio.

^a*Data are reported as effect size r (p-value), where r = Z/√N.

The distribution of blood groups among TTP patients revealed that blood group O was the most prevalent (37.7%, n=43), followed by group A (35.1%, n=40), group B (20.2%, n=23), and group AB (7.0%, n=8).

3.4 Therapeutic Approaches

Table 7 shows the frequency of therapeutic agents used in TTP patients. Plasmapheresis was the most commonly employed modality (90.4%), followed by heparin (71.9%) and red blood cell transfusions (68.4%). Corticosteroids, prednisolone, and other immunosuppressive agents were also utilized. Given that treatment assignment was not randomized, associations between therapeutic modalities and inflammatory indices or clinical outcomes should be interpreted as hypothesis-generating rather than causal.

Table 7.

Therapeutic Strategies of TTP Patients

Therapeutic approaches	TTP patients, n (%)
	Treated with	Untreated with
Plasmapheresis	103 (90.4)	11 (9.6)
Red blood cells transfusion	78 (68.4)	36 (31.6)
Corton	56 (49.1)	58 (51.9)
IVIG	20 (17.5)	94 (82.5)
Heparin	82 (71.9)	32 (28.1)
Rituximab	16 (14)	98 (86)
Prednisolone	75 (65.8)	39 (34.2)
Pantoprazole	65 (85.5)	11 (14.5)
Hydrocortisone	43 (56.6)	33 (43.4)
Hydroxychloroquine	18 (15.8)	96 (84.2)
Cyclosporine	9 (7.9)	105 (92.1)
Azathioprine	14 (12.3)	100 (87.7)
Dexamethasone	47 (61.8)	29 (38.2)
Antibiotics	60 (78.9)	16 (21.1)

Abbreviations: TTP, Thrombotic thrombocytopenic purpura; IVIg, intravenous immune globulin. Transfusional therapy (Plasmapheresis, FFP, Red blood cells transfusion, IVIG), Immunosuppressive therapy (Cortons/Steroids, Rituximab, Azathioprine, Cyclosporine, Prednisolone, Hydroxychloroquine).

Table 8 presents the associations between individual and grouped therapeutic strategies and post-treatment outcomes. Several treatments showed significant associations with hospitalization duration: plasmapheresis (r = 0.348, P < 0.001), IVIG (r = 0.221, P = 0.023), Corton (r = 0.240, P = 0.014), heparin (r = 0.510, P < 0.001), rituximab (r = 0.238, P = 0.018), hydrocortisone (r = 0.240, P = 0.036), azathioprine (r = 0.276, P = 0.004), and antibiotics (r = 0.340, P = 0.003). Significant associations with post-treatment platelet counts were observed for Corton (P = 0.001), heparin (P < 0.001), cyclosporine (P = 0.007), azathioprine (P = 0.001), and dexamethasone (P = 0.032). Heparin, Corton, cyclosporine, and azathioprine were also significantly associated with post-treatment NLR and HPR (all P < 0.05). When therapeutic strategies were grouped into transfusional therapy alone, immunosuppressive therapy alone, and combined transfusional plus immunosuppressive therapy, the treatment group was significantly associated with hospitalization duration (P = 0.002) and post-treatment platelet count (P = 0.047). Given the non-randomized, retrospective nature of treatment assignment, these associations should be interpreted as exploratory and hypothesis-generating, as they may reflect disease severity and clinician preference rather than direct causal effects. Association between hospitalization, Status and CRP, ESR (At the time of diagnosis & after treatment) are presented in Table 9.

Table 8.

Association Between Hospitalization, Hematological Parameters, and Single Therapeutic Strategies Along With Multiple Therapeutic Strategies of TTP Patients

Therapeutic strategies	Effect size (p-value) a
	Hospitalization	Plt	PLR	NLR	HPR
		After treatment
Plasmapheresis	0.348 (<0.001)*	0.088 (0.344)	0.033 (0.719)	0.198 (0.034)*	0.022 (0.814)
Red blood cell transfusion	0.070 (0.469)	0.101 (0.281)	0.113 (0.227)	0.040 (0.670)	0.050 (0.587)
IVIG	0.221 (0.023)*	0.078 (0.404)	0.020 (0.823)	0.011 (0.905)	0.019 (0.832)
Corton	0.240 (0.014)*	0.309 (0.001)*	0.016 (0.856)	0.232 (0.013)*	0.266 (0.004)*
Heparin	0.510 (<0.001)*	0.531 (<0.001)*	0.274 (0.003)*	0.319 (0.001)*	0.496 (<0.001)*
Rituximab	0.238 (0.018)*	0.102 (0.276)	0.081 (0.387)	0.037 (0.692)	0.152 (0.104)
Prednisolone	0.094 (0.330)	0.002 (0.981)	0.078 (0.405)	0.045 (0.629)	0.005 (0.955)
Pantoprazole	0.157 (0.106)	0.021 (0.819)	0.006 (0.947)	0.015 (0.865)	0.088 (0.345)
Hydrocortisone	0.240 (0.036)*	0.098 (0.390)	0.006 (0.954)	0.073 (0.523)	0.124 (0.278)
Hydroxychloroquine	0.088 (0.361)	0.088 (0.343)	0.079 (0.397)	0.160 (0.087)	0.097 (0.300)
Cyclosporine	0.131 (0.175)	0.251 (0.007)*	0.105 (0.259)	0.238 (0.011)*	0.213 (0.023)*
Azathioprine	0.276 (0.004)*	0.321 (0.001)*	0.085 (0.360)	0.316 (0.001)*	0.315 (0.001)*
Dexamethasone	0.202 (0.078)*	0.246 (0.032)*	0.091 (0.426)	0.069 (0.546)	0.216 (0.059)
Antibiotics	0.340 (0.003)*	0.033 (0.769)	0.016 (0.889)	0.152 (0.185)	0.013 (0.909)
Different drugs groups	0.096 (0.002)*	0.037 (0.47)*	0.011 (0.714)	0.054 (0.018)*	0.035 (0.051)

Note. The analysis for therapeutic strategies was performed based on the Wilcoxon–Mann–Whitney test. Note. The analysis for multiple therapeutic strategies was performed based on the Kruskal–Wallis Test. Abbreviations: Hb, hemoglobin; Hct, hematocrit; HPR, hemoglobin‐to‐platelet ratio; TTP, Thrombotic thrombocytopenic purpura; NLR, neutrophil-to-lymphocyte ratio; PLR, platelet‐to‐lymphocyte ratio.

^a*Data are reported as effect size r (p-value), where r = Z/√N.

Group 1: Transfusional therapy,

Group 2: Immunosuppressive therapy,

Group 3: Transfusional therapy+ Immunosuppressive therapy.

Table 9.

Association Between Hospitalization, Status and CRP, ESR (at the Time of Diagnosis & After Treatment)

Variables	Effect size (p-value) a				Hospitalization
	CRP	ESR	CRP	ESR
	At the time of diagnosis		After treatment
Hospitalization	0.264 (0.028)*	0.137 (0.252)	0.171 (0.413)	0.244 (0.102)	-
Status (Betterment or Death)	0.190 (0.101)	0.226 (0.047)*	0.063 (0.737)	0.049 (0.720)	0.219 (0.024)*

Note. The analysis for multiple therapeutic strategies has been done using Spearman’s ρ test. Abbreviations: CRP, C-reactive protein; ESR, Erythrocyte sedimentation rate; TTP, Thrombotic thrombocytopenic purpura.

^a*Data are reported as effect size r (p-value), where r = Z/√N.

4. Discussion

Thrombotic thrombocytopenic purpura (TTP) is a complex disorder that can manifest in inherited or immune-mediated forms. ³⁹ This case-control study evaluated the diagnostic utility of NLR, PLR, and HPR in patients with TTP compared with healthy individuals. Our principal finding was that NLR and HPR were significantly elevated in TTP patients, while PLR was significantly reduced. These results are biologically plausible and align with the dual mechanisms driving TTP pathophysiology: systemic inflammation and microvascular platelet consumption.

In this study, we evaluated inflammatory parameters including cell counts, PLR, NLR, and HPR in TTP patients compared to controls. Our findings showed that NLR and HPR were significantly increased, while PLR was decreased, consistent with our previous work in ITP and other studies.^40,41 NLR was correlated with renal symptoms, while PLR and HPR were associated with systemic symptoms and thrombocytopenia, in line with studies on thrombosis and inflammatory conditions. ⁴² Our findings are largely consistent with the growing body of evidence linking CBC-derived inflammatory ratios to thrombotic and vascular disease states. Songur et al demonstrated that elevated PLR predicted amputation risk in critical limb ischemia, reflecting the interplay between platelet activation and peripheral vascular occlusion. ²⁴ Lafci et al reported that admission NLR was independently associated with in-hospital mortality in acute type I aortic dissection, showing the prognostic relevance of neutrophil-predominant inflammation in acute large-vessel thrombosis. ²⁵ The current study extends these observations into the microvascular thrombotic domain of TTP, suggesting that similar immune-thrombotic mechanisms may be operational across a spectrum of vascular disorders.

Demographically, the median age of our patients (33.82 ± 10.60) was consistent with Iqbal et al, though symptom distribution differed; they reported cardiac and neurological features in 91% and renal symptoms in 45% of patients. ⁴³ Hematologically, our patients had higher WBC and neutrophil counts and lower platelet, RBC, and lymphocyte counts than controls, consistent with previous reports. Deng et al found that 81% of TTP patients had the classic triad of hemolytic anemia, thrombocytopenia, and neurologic abnormalities, with 60.9% showing decreased CD4 counts. ⁴⁴

The prognostic value of NLR and PLR in our cohort aligns with findings by Staley, who reported poor platelet normalization, LDH reduction, and elevated troponin as predictors of mortality, alongside prolonged aPTT and complement activation markers. ⁴⁵ Increased neutrophil counts and lymphopenia have been linked to worse prognosis, emphasizing their importance in monitoring. Neutrophils may contribute to TTP pathogenesis through phagocytosis of antibody-sensitized ADAMTS13 and cytokine production (IL-8), suggesting therapeutic strategies targeting neutrophil Fc receptors and cytokines could be explored. ⁴⁶

The diagnostic and predictive significance of NLR and PLR has been recognized in other inflammatory conditions. Tang et al reported elevated NLR and PLR in COPD non-survivors, with NLR correlating with CRP. ⁴⁷ Omnia et al showed their predictive value in cardiovascular disease, ⁴⁸ and Rathod et al found NLR significantly higher in severe COVID-19 patients. ⁴⁹ Although predictive value has been established in myocardial infarction, pneumonia, and pulmonary embolism, ⁵⁰ data on TTP remain limited.

Treatment associations in our study were notable. NLR before and after therapy correlated with plasmapheresis, heparin, and Corton, while ANC before treatment was directly related to hospitalization length. Shi et al similarly reported higher NLR in non-survivors and less plasma exchange in this group. ⁵¹ Lymphopenia was also evident in our patients, consistent with studies in SLE-associated TTP where it was an independent risk factor. ⁵² Fever was associated with reduced platelet count, decreased PLR, and increased HPR. Plasmapheresis correlated with NLR and hospitalization length, while heparin and Corton were linked to higher NLR. Cyclosporine was positively correlated with all indices except PLR.

Overall, increased NLR was associated with prolonged hospitalization, highlighting its prognostic importance. ⁵³ Wu et al confirmed NLR associations in contrast-induced nephropathy, ⁵⁴ though findings in autoimmune diseases such as Behcet’s and psoriasis remain inconsistent.^55,56 Taken together, our findings emphasize that cellular and non-cellular factors—including WBC, neutrophils, lymphocytes, PLR, NLR, and HPR—can be valuable in identifying and monitoring TTP patients. Although their role in autoimmune diseases remains uncertain, these indices hold significant importance for prognosis, diagnosis, and treatment in TTP. Several important limitations warrant careful consideration. First, ADAMTS13 activity measurement—currently regarded as the gold standard for confirming TTP diagnosis—was not available for the majority of patients in this cohort. Instead, diagnosis relied on the 2023 British Society for Hematology guideline criteria, which include thrombocytopenia, microangiopathic hemolytic anemia, and compatible clinical features. While this reflects real-world clinical practice in many settings where specialized ADAMTS13 testing is not readily accessible at the time of initial presentation, it raises the possibility that a subset of patients may have had alternative thrombotic microangiopathies. Second, the retrospective, single-center design limits the generalizability of our findings and precludes causal inference regarding the relationship between inflammatory indices and clinical outcomes, multicenter studies are needed to validate our findings. Third, treatment assignments were non-randomized and based on physician discretion and institutional protocols, meaning that any observed associations between therapeutic modalities and laboratory indices may be confounded by disease severity and indication bias. Fourth, the large number of exploratory comparisons between clinical symptoms and hematological parameters increases the risk of false-positive findings; formal multiplicity adjustments were not applied, and marginal associations should be interpreted cautiously. Finally, the control group was deliberately enriched with individuals in the low-to-mid normal platelet range, which—while methodologically intentional as a diagnostic challenge—may not fully represent the general healthy population.

5. Conclusion

This study demonstrates that NLR and HPR are significantly elevated, while PLR is significantly decreased, in patients with TTP compared with healthy controls. These readily available CBC-derived indices may serve as adjunctive laboratory markers to support the clinical diagnosis of TTP, particularly in settings where definitive ADAMTS13 testing is not immediately accessible. However, given the retrospective single-center design, the absence of ADAMTS13 confirmation in the majority of cases, and the lack of external validation for the proposed cut-off values, these findings should be regarded as preliminary and hypothesis-generating. Future prospective, multi-centre studies incorporating ADAMTS13 activity measurement and external validation cohorts are required to confirm the diagnostic and prognostic utility of NLR, PLR, and HPR in TTP before they can be recommended for routine clinical application.

ORCID iDs

Mohammad Reza Meghdadi https://orcid.org/0009-0009-0967-6625

Seyed Nasser Hosseinian https://orcid.org/0000-0002-1448-008X

Mohammad Hossein Ahmadi https://orcid.org/0000-0002-3414-5019

Mohammad Reza Keramati https://orcid.org/0000-0003-4160-4161

Data Availability Statement

The data that support the findings of this study are available from Mashhad University of Medical Sciences. Restrictions apply to the availability of these data, which were used under license for this study. Data are available from Mohammad Hossein Ahmadi with the permission of Mashhad University of Medical Sciences.*