Immunosuppression in two cases of indeterminate hepatitis

Abstract

Background:

Pediatric acute liver failure (PALF) is a potentially lethal and rapidly progressive clinical syndrome, with a large proportion of cases remaining indeterminate despite extensive investigations.

Patients and Results:

In this case report, we describe two male children with indeterminate PALF and a family history of autoimmune disease, both of whom were lymphopenic with necrosis, inflammation, and lymphocytic infiltrates on their liver biopsies. One of these patients subsequently developed hepatitis-associated aplastic anemia. Notably, in addition to receiving standard liver failure care, both patients were successfully treated off-label with anti-thymocyte globulin (ATG), as well as a more prolonged course of cyclosporine and corticosteroids.

Conclusions:

The fact that these medications all suppress T lymphocytes further supports the theory that T-cell activation plays a prominent role in the pathophysiology of indeterminate hepatitis. Further research should examine the short-term and long-term effects of ATG in this population, as well as the necessary duration of treatment with immune-suppressing agents.

Introduction

Pediatric acute liver failure (PALF) is a potentially lethal and rapidly progressive clinical syndrome. It has been defined as acute onset of liver disease without signs of chronicity, biochemical evidence of severe liver injury, and coagulopathy not corrected by Vitamin K (1).

Potential causes of PALF include but are not limited to infectious (primarily viral), autoimmune, medication- or toxin-induced, metabolic, and more (2). There exists, however, a large proportion of PALF patients (30%–43%) for whom an etiology is never elucidated, with their diagnosis ultimately remaining indeterminate (IND-PALF) (2–4).

A common pattern has recently been identified among IND-PALF patients; namely, T-cell activation with a presumed resultant immune-mediated liver injury (3).

In this case report, we describe two patients with IND-PALF who, in addition to receiving standard care for liver failure, were successfully treated with immune suppression targeting T lymphocytes.

Case Report

Patient 1:

A 13-year-old male presented to the emergency department with 5 days of decreased oral intake, vomiting, and progressive jaundice. He had no associated symptoms, but family history was significant for several immune-mediated diseases in first- and second-degree relatives, including Crohn's disease, immune thrombocytopenia (ITP), and bone marrow aplasia.

Laboratories obtained in the emergency department revealed elevated AST 1677 U/L, ALT 2519 U/L, total bilirubin 168 μmol/L, direct bilirubin 101 μmol/L, GGT 88 U/L, and INR 1.19. Albumin was 39 g/L. Initial CBC was normal, with WBC 5.1 × 10⁹/L, Hb 135 g/L, and Plt 245 × 10⁹/L. He was admitted to the hospital 48 hours later.

During his hospitalization, an etiologic work-up was performed (Table 1) and was negative. Fifteen days after symptom onset, he began to develop a bicytopenia. Platelets dropped as low as 72 × 10⁹/L with WBC 4.2 × 10⁹/L and lymphocytes 0.38 × 10⁹/L.

Table 1:

Etiologic work-up for indeterminate hepatitis carried out on both patients

Etiology	Investigations performed
Infectious	Nasopharyngeal swab for respiratory viruses Stool viral PCR Hepatitis A, B, C, E CMV EBV Parvovirus Parechovirus HSV-1 and HSV-2 HHV-6 Toxoplasmosis
Autoimmune	IgG ANA Anti-smooth muscle antibodies Anti-mitochondrial antibodies Anti-parietal cell antibodies Anti-liver-kidney microsomal antibodies
Metabolic	Ceruloplasmin Serum copper levels 24-hour urine copper collection Ophthalmologic exam Alpha-1 antitrypsin Serum amino acids Urine organic acids
Toxic ingestion	Acetaminophen level Urine toxin screen
Other	IgA TTG TSH

At the transplant center, the patient's AST and ALT continued to worsen, and INR peaked at 3.63.

Liver biopsy revealed an inflammatory liver infiltrate with hepatocellular necrosis, lymphocytes, monocytes, polynuclear neutrophils, and eosinophils. He was treated with four doses of rabbit rabbit Anti-Thymocyte Globulin (ATG) (2 mg/kg), with a significant resultant decrease in his AST and ALT (Figure 1). He unfortunately developed serum sickness after his second dose, with features of hepatic encephalopathy and an ammonia level of 136 g/L.

Figure 1:

Laboratory values from day of presentation (day 0) until last available follow-up. AST, ALT, total bilirubin, and direct bilirubin are shown. Treatments are indicated below the graph—the first course of ATG was rabbit ATG, and the second was equine

ALT = alanine transaminase; AST = aspartate transaminase; ATG = antithymocyte globulin; Direct bili = direct bilirubin; Total bili = total bilirubin

Persistent bicytopenia was noted, with his bone marrow being hypocellular (60% richness) on bone marrow biopsy. He was diagnosed with Hepatitis Associated Aplastic Anemia (HAAA) (5) and was treated with 4 days of equine ATG (40 mg/kg). Cyclosporine was then initiated.

As an outpatient, his blood work continued to normalize. Alongside the end of his prednisone taper, he experienced a transient recurrence of ALT/AST increase with no associated hyperbilirubinemia. His liver function tests have been normal for almost 1 year now, with the only treatment change having been the discontinuation of cyclosporine in favor of sirolimus due to a rising creatinine. Repeat bone marrow biopsy 8 months after discharge found an improvement in his hypocellularity, from 60% to 85%. Platelets and neutrophils reached low normal levels at 16 and 12 months after the onset of the disease, respectively. At the last control, lymphopenia was still present, and the peripheral blood analysis showed a decrease mainly of circulating CD4 + T cells.

Patient 2:

A previously healthy 9-year-old male presented to the emergency department with 4 days of jaundice and decreased energy. He had normal stools, no viral symptoms aside from mild rhinorrhea, no history of toxic ingestions, and no abdominal pain, nausea, vomiting, or rash.

Family history was notable for a grandparent with lupus.

Laboratories obtained in the emergency department revealed elevated AST 2591 U/L, ALT 1984 U/L, total bilirubin 408 μmol/L, direct bilirubin 302 μmol/L, GGT 72 U/L, lipase 279 U/L, and INR 1.70. Albumin was 38 g/L, with WBC 4.4 × 10⁹/L, Hb 136 g/L, and Plt 196 × 10⁹/L. Ammonia was within normal range at 19 μmol/L. He tested positive for Rhinovirus. A thorough panel of etiologic investigations was performed, all of which were negative (Table 1). Abdominal ultrasound revealed severe gallbladder thickening with hepatitis and hepatomegaly. The patient developed lymphopenia (lymphocytes of 0.5) and further progression of his liver failure (INR = 3.75), despite decrease in ALT/AST serum levels, prompting transfer to a transplant center for further management.

Liver biopsy revealed hepatocellular necrosis comprising >30% of his hepatocytes, as well as a diffuse inflammatory infiltrate of CD3+CD8+ T lymphocytes. Given his lymphopenia and the lymphocytic infiltration on liver biopsy, off-label treatment with rabbit ATG was initiated. After completing five doses of ATG (first dose: 0.75 mg/kg, remaining doses: 1.5 mg/kg), he was transitioned to cyclosporine. However, due to subsequent increases in bilirubin, an additional three doses of ATG were given alongside cyclosporine before ultimately initiating a prolonged prednisone taper (Figure 2).

Figure 2:

Laboratory values from day of presentation (day 0) until last available follow-up. AST, ALT, total bilirubin, and direct bilirubin are shown. Treatments are indicated below the graph

AST = aspartate transaminase, ALT = alanine transaminase, ATG = antithymocyte globulin, cyclo = cyclosporine, Direct bili = direct bilirubin, Total bili = total bilirubin.

At the time of discharge, the patient's liver enzymes were approaching normalization. He experienced a transient and self-resolving increase in liver enzymes approximately 3 months after discharge, with AST peaking at 239 U/L and ALT peaking at 577 U/L. His bilirubin and liver function tests remained normal throughout, and he is currently showing normal liver tests on cyclosporine and low dose hydrocortisone. Nevertheless, he still showed a relative lymphopenia at the last control, 8 months after the beginning of the immunosuppressive treatment, though he has normal platelets and neutrophils in the lower range.

Discussion

In this case series, we present two male children with IND-PALF, both of whom were lymphopenic, with necrosis, inflammation, and T lymphocytic infiltrates on their liver biopsies. Both patients had a family history of autoimmune disease and were successfully treated with ATG, as well as with a more prolonged course of cyclosporine and corticosteroids. Both patients also had subsequent transient, self-resolving episodes of elevated transaminases with no associated hepatic dysfunction.

The clinical presentation of our patients closely resembles the phenomenon described by Chapin et al., who found dense CD8+ immunohistochemical staining in 82% of IND-PALF patients as compared to only 7% of those with known diagnoses, thus demonstrating evidence of T-cell activation in this population (3). Such T-cell expansion shows particular characteristics as: Th1 pattern, increase in memory and cytotoxic T cells, high perforin and granzyme expression, and high serum levels of IL25R (5,6). It was also showed that the presence of an increase in effector memory CD8+ CD3+ T-cells in peripheral blood indicates a tendency to respond to immunosuppressive therapy in children with IND-PALF (7). Activation markers in circulating T lymphocytes identify a subgroup of PALF patients with a distinct phenotype, more frequently requiring a liver transplantation (6).

The search for viruses by PCR on liver biopsy was negative, leading to the conclusion that the liver injury in these patients is immune-mediated (8,9).

The increased risk of HAAA documented in IND-PALF patients (16–30%, mainly in those with lymphopenia) further supports the theory that their liver injury was immune-mediated, further supported the theory that their liver injury was immune-mediated (10). Some of these patients have been shown to demonstrate a good response to high-dose corticosteroids (3,11). Recently, in a case series of children with HAAA, the relevance of ATG in improving liver outcomes was shown (12). In our patients, IND-PALF associated with deep lymphopenia led to the administration of ATG. This is the first-line treatment for patients with HAAA, when a good donor is not available for a bone marrow transplant. In addition, many liver transplant centers administer ATG during the immunosuppression induction phase post-transplant.

This case series documents significant clinical and biochemical response in IND-PALF patients after treatment with ATG, an immunosuppressant with T-cell depletion as its most prominent effect. Patients were also treated with cyclosporine and prednisone, both of which diminish or affect T lymphocyte activation and proliferation (13,14). Future research should examine the short-term and long-term effects of ATG in this population, as well as the necessary duration of treatment with immune-suppressing agents. Currently, a prospective trial (TRIUMPH-TReatment for ImmUne Mediated PathopHysiology) on the use of ATG in children with indeterminate acute liver failure is being carried out (NCT04862221) in North America.

Contributions:

A. Cohen: Revision of charts. Writing of first draft. F. Alvarez: Conception of the article. Revision of the final version.

Ethics Approval:

Ethical approval was obtained for this manuscript.

Informed Consent:

Consent was received from the parents of both patients.

Registry and the Registration No. of the Study/Trial:

N/A

Data Accessibility:

All data will not be publicly available. Researchers who require access to the study data can contact the corresponding author for further information.

Funding:

N/A

Disclosures:

N/A

Peer Review:

N/A

Animal Studies:

N/A