Donor-derived Ehrlichiosis: 2 Clusters Following Solid Organ Transplantation

Abstract

Ehrlichiosis has been infrequently described as transmissible through organ transplantation. Two donor-derived clusters of ehrlichiosis are described here. During the summer of 2020, 2 cases of ehrlichiosis were reported to the Organ Procurement and Transplantation Network (OPTN) and the Centers for Disease Control and Prevention (CDC) for investigation. Additional transplant centers were contacted to investigate similar illness in other recipients and samples were sent to the CDC. Two kidney recipients from a common donor developed fatal ehrlichiosis-induced hemophagocytic lymphocytic histiocytosis. Two kidney recipients and a liver recipient from another common donor developed ehrlichiosis. All 3 were successfully treated. Clinicians should consider donor-derived ehrlichiosis when evaluating recipients with fever early after transplantation after more common causes are ruled out, especially if the donor has epidemiological risk factors for infection. Suspected cases should be reported to the organ procurement organization and the OPTN for further investigation by public health authorities.

Ehrlichiosis is a rare donor-derived infection. Simultaneous manifestation as fatal hemophagocytic lymphocytic histiocytosis in organ transplant recipients has not been reported. Early detection and empiric ehrlichiosis treatment may improve outcomes.

Human ehrlichiosis is a tickborne disease emerging in the United States caused by 3 known human pathogens: Ehrlichia chaffeensis, Ehrlichia ewingii, and Ehrlichia muris eauclairensis. E chaffeensis is presumed to be the most common human disease agent with the majority of cases reported from the southeastern and south-central United States [1]. In immunocompetent individuals, symptoms usually manifest as fever, chills, myalgia, and headache [2]. Ehrlichiosis is not commonly associated with hemophagocytic lymphocytic histiocytosis but has been reported [3, 4]. Since the original description in 1987, cases of ehrlichiosis have been increasing in incidence and geographic range. The incidence of reported ehrlichiosis has increased 4-fold between 2000 and 2012, with more than one-half of all cases reported from Oklahoma, Missouri, Delaware, Arkansas, Virginia, and Tennessee. Cases of ehrlichiosis in transplant patients are considered rare but have been previously reported [5–7].

In the United States, all suspected, unexpected donor-derived infections are reported by organ procurement organizations or transplant centers to the Organ Procurement and Transplantation Network (OPTN) for investigation by the ad hoc Disease Transmission Advisory Committee. Select cases of public health significance are referred to the Centers for Disease Control and Prevention (CDC) for investigation. We describe the clinical features and public health investigation of 2 clusters of ehrlichiosis in the United States among organ transplant recipients, likely transmitted through solid organ transplantation. These infections were reported to the OPTN with further investigation by state health departments and the CDC.

METHODS

Public Health Investigation

To determine whether the deceased organ recipients acquired ehrlichiosis through transplantation and to identify other potentially infected recipients from the same donor, medical records of the donor and recipients were reviewed. Interviews with the next of kin for each donor (deceased donor A and deceased donor B) were conducted before organ procurement and were reviewed. Following the diagnosis of ehrlichiosis at a transplant center and reporting by organ procurement organizations to the CDC further inquiries were performed. Medical teams treating each recipient provided details about the recipient’s medical history along with their posttransplant clinical course.

Laboratory Specimen Collection and Testing

Testing made during the diagnostic workup of live patients was performed using commercial polymerase chain reaction (PCR) assays using either real-time PCR techniques or combination real-time and DNA probe hybridization with melting point curve analysis [8, 9]. The CDC’s Rickettsial Diagnostic Laboratory received several samples from both clusters for confirmatory testing using Ehrlichia species and E chaffeensis real-time PCR assays and serology. Postmortem sections of 1 recipient’s liver and lung, as well as bone marrow biopsies of another recipient, were obtained were obtained and analyzed at the CDC’s Infectious Disease Pathology Laboratory using immunohistochemistry.

CASE REPORTS

All the recipients were transplanted in 2020 and shared the following medication regimen. All received induction immunosuppression with Thymoglobulin and methylprednisolone and maintenance immunosuppression with tacrolimus and mycophenolic acid (MPA). All received antimicrobial prophylaxis with trimethoprim-sulfamethoxazole and valganciclovir.

Deceased Donor A

In June 2020, a 57-year-old male resident of Delaware with a history of illicit drug use and hypertension was found unresponsive. Donor serology was positive for hepatitis C antibody, hepatitis B core antibody, and Epstein-Barr virus. Hepatitis B and C PCRs were negative. Before the organ procurement organization’s (OPO) involvement, skin lesions were noted, biopsied, and sent to the Mayo Clinic for pathologic analysis. The day after the transplants, the OPO and the transplant centers were alerted to the lesions being identified by microscopy as Amblyomma spp nymph stage ticks. Although this is the suspected source of the ehrlichiosis infection, it is not the most common vector in that region; however, its identity was confirmed by gross examination and microscopy. Perimortem serum and lymphocytes were negative for Ehrlichia spp and E chaffeensis real-time PCR assays at the CDC’s Rickettsial Diagnostic Laboratory.

Recipient A1

A 70-year-old man with end-stage renal disease (ESRD) from polycystic kidney disease underwent a preemptive kidney transplant (KT) from donor A (Figure 1). He resided in and was transplanted in New Jersey. He had slow graft function but did not require dialysis and was discharged on posttransplant day (PTD) 4. He presented to the emergency room on PTD 17 with a fever of 38.3°C, chills, cough, diarrhea, and headache. Examination was significant for conjunctival pallor and bilateral 2+ pedal edema. Laboratory tests revealed expected findings of postinduction lymphocyte depletion.

Figure 1.

Donor A ehrlichiosis transmission.

He continued to spike fevers and remained pancytopenic despite discontinuation of MPA and valganciclovir and administration of empiric antibiotics. On PTD 21, hemophagocytic lymphohistiocytosis (HLH) was suspected (based on pancytopenia and elevated inflammatory markers), and bone marrow biopsy was performed with results consistent with HLH. The patient was started on dexamethasone and etoposide for treatment of HLH. On PTD 24, peripheral blood smear was reported as having intracytoplasmic neutrophil inclusions. Doxycycline and caspofungin were started. Immunoglobulin G (IgG) and IgM antibodies reactive against E chaffeensis were negative. Blood collected at admission resulted positive for E chaffeensis using commercial real-time PCR assay on PTD 25. He was continued on doxycycline with resolution of chills and fever. The patient’s neutropenia and thrombocytopenia were unresponsive to multiple therapies. A lumbar puncture (performed after seizure episodes on PTD 25) revealed a high level of protein and but negative for infectious etiology, including ehrlichiosis. He developed Escherichia coli septicemia on PTD 30, lower extremity deep vein thrombosis on PTD 34, and candida fungemia on PTD 35. He had preserved allograft function but deteriorating mental status. Possible central nervous system involvement with HLH was suspected and treated with intrathecal methotrexate and hydrocortisone on PTD 41. On PTD 43, care was shifted to comfort care and the patient died on PTD 51. CDC analysis of postmortem sections of liver and lung showed no immunohistochemical evidence of Ehrlichia infections. However, abundant hyphal elements consistent with mucoromycete fungus were observed.

Recipient A2

A 66-year-old male with ESRD from type 2 diabetes and a right nephrectomy for renal cell carcinoma on hemodialysis received a KT from donor A. He resided in New York and was transplanted in Pennsylvania (Figure 1). Eight months prior, the patient was diagnosed and treated with steroids for adult-onset Still disease (AOSD). The patient had slow graft function but did not require dialysis and was discharged on PTD 7. He presented to the emergency room on PTD 10 with a 1-day history of fatigue and fever of 38.7°C. Examination was unremarkable. The patient developed worsening fevers, fatigue, declining renal function, and altered mental status. Tacrolimus was lowered and MPA discontinued. Pancytopenia worsened and a bone marrow biopsy on PTD 15 was consistent with HLH. A lumbar puncture could not be obtained because of thrombocytopenia. HLH was treated with corticosteroids and anakinra. The patient’s mental status declined, requiring intubation. Hemodialysis was initiated for volume overload and uremia. On PTDs 10 and 11, plasmapheresis with fresh frozen plasma exchange followed by intravenous immunoglobulin was administered for additional treatment of HLH. On PTD 21, the patient had a cardiac arrest, after which he displayed only basic brain stem function; comfort care was initiated followed by death on the same day. Perimortem, recipient A1’s center called with information of their recipient’s results suggesting ehrlichiosis. A postmortem blood specimen was positive for E chaffeensis by commercial qualitative PCR. CDC analysis of a bone marrow biopsy from PTD 15 for recipient A2 showed immunohistochemical evidence of Ehrlichia spp. Pretransplant serum samples for recipient A2 were negative by both PCR and immunofluorescence antibody, and posttransplant serum samples were positive for E chaffeensis by real-time PCR confirming a posttransplant infection.

Deceased Donor B

In August 2020, a 29-year-old male resident of Missouri with a history of illicit drug use and asthma committed suicide. Donor serologies were negative for hepatitis B and C. During the donor’s physical assessment, a tick on his inner thigh was noticed and documented before organ acceptance. CDC analysis of perimortem serum and plasma were negative by real-time PCR, but showed low-level (1:64) IgG antibody titers to Ehrlichiosis.

Recipient B1

A 5-year-old Missouri resident with ESRD from obstructive uropathy (posterior urethral valves) received a KT in Missouri (Figure 2). He was discharged on PTD 6. He presented to the emergency room on PTD 9 with diarrhea and fever of 38.3°C. Examination was significant for conjunctival pallor and bilateral 2+ pedal edema. He was started on empiric ceftriaxone. He continued to have daily fevers despite broadening coverage to cefepime and developed pancytopenia. Infectious causes of pancytopenia were sought including tick-transmitted infections. Samples taken on PTD 15 were positive for Ehrlichia spp using commercial PCR assay and his laboratory evaluation was concerning for Ehrlichia-associated HLH. Doxycycline was initiated. Ferritin peaked at 13 354 and triglycerides at 287 but did not meet full criteria for HLH. Doxycycline for 14 days was completed, and he recovered without sequelae.

Figure 2.

Donor B ehrlichiosis transmission.

Recipient B2

A 6-year-old Missouri resident with ESRD from obstructive uropathy (posterior urethral valves) received a KT in Missouri (Figure 2). His posttransplant course was complicated by fever on PTD 9 to 38.8°C which was found to be secondary to ehrlichiosis (diagnosed by positive E chaffeensis by commercial real-time PCR on PTD 17) and secondary HLH (diagnosed based on elevated ferritin to 31 891 ng/mL and bone marrow biopsy with hemophagocytic histiocytes). He was treated with dexamethasone from PTD 17 until PTD 39 when improvement in ferritin and soluble interleukin-2R demonstrated resolution of HLH. He was switched from steroid dosing for treatment of HLH to dosing for steroid-based immunosuppression protocol with prednisolone ~0.4 mg/kg/d. He recovered from HLH and ehrlichiosis (after treatment with doxycycline for 10 days) without sequelae.

Recipient B3

A 63-year-old male with a history of sarcoidosis and pulmonary hypertension underwent right lung transplant (Figure 2). Maintenance immunosuppression also included prednisone. Prophylaxis included a 2-week course of meropenem and linezolid with long-term prophylaxis included fluconazole. Donor B’s bronchoalveolar lavage was positive for Staphylococcus aureus. Patient had a relatively uncomplicated hospital course and was discharged PTD 17. On PTD 18, doxycycline was started after communication of ehrlichiosis in recipient B1. He remained asymptomatic. Blood from PTD 23 was negative by commercial PCR assays for Ehrlichia spp. The patient is alive and well.

Recipient B4

A 52-year-old male with combined systolic and diastolic heart failure who had previously undergone aortic valve replacement and left ventricular assist device implantation complicated by recurrent methicillin-susceptible S aureus driveline infection requiring suppressive treatment with cephalexin received a heart transplant (Figure 2). Cefazolin continued through the peritransplant period. His first endomyocardial biopsy demonstrated moderate acute cellular rejection (2R) and mild antibody-mediated rejection (1), and he received a 3-day course of methylprednisolone. At discharge on PTD 18, maintenance immunosuppression also included prednisone. On that day, the center was informed of the donor B’s tick attachment and that recipient B1 had ehrlichiosis. Doxycycline was prescribed for 14 days. No Ehrlichia testing was performed. At this time, the patient is doing well and is asymptomatic.

Recipient B5

A 69-year-old male underwent liver transplantation for hepatitis C-related cirrhosis (Figure 2). Induction was methylprednisolone only. The immediate postoperative course was uneventful and he was discharged on postoperative day 4 on tacrolimus, MPA, and tapering prednisone. One day after discharge, the steroid dose was increased for rising aminotransferases and bilirubin. On PTD 11, the patient developed hyponatremia, headache, malaise, agitation, and fever (38°C) and was hospitalized. Ehrlichia PCR testing was positive and oral doxycycline was given for 14 days. Liver biopsy on PTD 12 revealed lobular hepatocyte apoptosis and occasional foci of lobular lymphohistiocytic inflammation. The patient was discharged on PTD 17. Aminotransferases and bilirubin normalized by PTD 25. The remainder of his course was unremarkable and he is currently doing well.

DISCUSSION

The manuscript details 2 distinct clusters of deceased donor-derived Ehrlichia infections. From the first donor, both recipients developed ehrlichiosis in a relatively short period following transplant presenting in a near-identical manner. In addition, the rare manifestation of HLH in both recipients during the height of the coronavirus disease 2019 pandemic, lack of response to broad-spectrum antibiotics, and associated rapid mortality is notable. A similar degree of severity of illness and transmission to all organ recipients was not seen in the case of donor B. It is unknown if this was due to a difference in strain, pediatric age group recipients, differences in organs transplanted, or earlier administration of doxycycline. There is a higher degree of suspicion of tickborne infection in Missouri, where the incidence is relatively high compared with the mid-Atlantic states. A noteworthy component of this manuscript is the open lines of communication and involvement of different partners involved in transplantation, including the CDC.

Ehrlichiosis includes a group of acute febrile tickborne diseases caused by closely related intracellular bacteria in the genera Ehrlichia [1]. Ehrlichia chaffeensis and E ewingii and E muris eauclairensis are 3 distinct species responsible for most cases of ehrlichiosis in the United States. Amblyomma americanum, the lone star tick, is broadly distributed in the eastern United States and is considered the primary vector for both E ewingii and E chaffeensis. Amblyomma maculatum, the Gulf Coast tick, extends from the Gulf Coast along the southern Atlantic coast, where new established populations of this vector have been noted in Delaware and is a rare vector of Ehrlichiae [10].

Infectious process with Ehrlichia spp starts with endocytosis and intracellular replication of the organism [11]. After endocytosis, organisms then replicate and multiply in cytoplasmic membrane bound vacuoles called morulae [4, 5]. Symptoms generally begin 5 to 14 days following tick bite. Early clinical signs and symptoms include fever, headache, malaise; gastrointestinal signs may be more common among pediatric case [1, 4]. Leukopenia, thrombocytopenia, and mild to moderate elevation in liver enzymes are usually observed in the immunocompetent host within the first week of illness onset. Rash is only present in roughly one-third of E chaffeensis cases and is more common among pediatric cases.

Ehrlichial illnesses in immunocompetent patients can range in disease severity, from mild to life-threatening with multisystem failures ultimately resulting from systemic inflammatory responses. Severe complications occur in 9% to 17% of cases and can include acute respiratory distress syndrome, disseminated intravascular coagulation-like syndrome, gastrointestinal bleeding, acute kidney injury, HLH, and death. In 20% of cases, ehrlichiosis has central nervous system involvement, leading to meningitis and meningoencephalitis [11]. Ehrlichia ewingii ehrlichiosis is generally considered to be less severe, and fatal cases have not been reported. Fatal outcome is reported in roughly 3% of E chaffeensis cases seeking medical attention, with higher case fatality rates among immunocompromised and older patients. Clinical manifestations are mostly the result of host inflammatory response rather than direct damage by the bacteria itself. This can lead to suppression of the apoptosis pathway in the host cell and modulation of cytokines and chemokines leading to exaggerated host response toward the bacteria [11].

Only a small number of ehrlichiosis cases have been reported in organ transplant recipients. Donor-derived ehrlichiosis within weeks after transplant has only been reported once previously. That case reports presented 2 cases of donor-derived ehrlichiosis in 2014 [12]. Transmission has also been described via blood product transfusion. Although a case report from 2013 did report a similar transmission, a case series from Nashville, TN, demonstrated the difference in clinical manifestations of ehrlichiosis between immunocompetent and immunosuppressed patients [13]. Solid organ transplant recipients experience less rash and lower hepatic enzymes but more leukopenia and renal dysfunction [1].

Diagnosis of ehrlichiosis in transplant patients remains a challenge. A high index of suspicion is vital not only for timely administration of antibiotics but also to prevent rapid progression to life-threatening complications, given the immunosuppressed state. PCR is a highly sensitive diagnostic tool for the presence of Ehrlichiae in peripheral blood or CSF and assays are widely available at commercial and reference laboratories. Ehrlichiae typically infect monocytes rather than neutrophils when seen in peripheral smears, like that seen in recipient A1, and can indicate concurrent intracellular infections. Indirect immunofluorescence antibody assays detecting IgG antibodies in serum is the standard laboratory investigation for diagnosis of ehrlichiosis. Immunofluorescence antibody assay is usually insensitive during the first week of infection; however, sensitivity increases significantly 2 to 3 weeks after the onset of illness [10, 11]. For serologic confirmation, collection of 2 serum samples at least 2 to 4 weeks apart is recommended [10]. A 4-fold rise in IgG titer within 3 weeks of initial symptoms with minimal titer of 1:64 has a sensitivity of >90% [14]. Serologic assays cannot confer species specificity as antibodies cross-react with closely related pathogens.

All diagnostic tests are subject to limitations. Serologic testing in the acute phase often has poor sensitivity and poor clinical specificity. One study documented fatal ehrlichiosis cases in which tissue samples were negative by PCR, but positive by immunohistochemistry, emphasizing the importance of using a combination of diagnostic tests [10]. Serologic testing in the acute phase often has poor sensitivity and poor clinical specificity. There are several PCR tests available but often only rely on a singleplex assay. Several novel laboratory-derived tests using multiplex panels have been reported that allow for better sensitivity and a broader range of testing and speciation in the acute setting [6]. Although the sensitivities of serologies are not ideal in the acute phase, PCR is often sensitive and specific enough to give us a genus level identification to allow for adequate treatment. Another confounding factor that must be considered with regard to confirming the diagnosis is that the lack of molecular evidence seen in some donor samples may reflect the age of samples at the time of testing and suboptimal sample types.

HLH is a rare but life-threatening condition caused by ineffective immunity against an antigen leading to dysregulated activation of the mononuclear macrophage system [15, 16]. In adults, infection is the most common cause of HLH. E chaffeensis is a rare trigger for HLH [3, 4]. Our cases are unique as both recipients of donor A developed HLH likely from ehrlichiosis and manifested early after transplant. The presence of ticks on both of the deceased donors raised the possibility of tickborne disease and, when present, can be a helpful to suspect donor-derived investigations. The differential diagnosis was further widened with both patients transplanted from donor A readmitted during a surge of the coronavirus disease 2019 pandemic, given that severe acute respiratory syndrome coronavirus 2 has also been associated with HLH [17]. Both recipients of donor A died, confirming the high mortality associated with HLH. For patient A2, the prior diagnosis of AOSD, also a rare cause of HLH, was another red herring. Most KT patients in the United States receive lymphocyte-depleting induction immunosuppression, and early posttransplant have varying degrees of pancytopenia that clouds those findings of tickborne infections. Both the lower severity of illness of donor B’s recipients and early recognition by their teams, because of greater awareness, helped contribute to the improved outcomes in the B recipient subgroup.

CONCLUSION

Despite best efforts to mitigate, donor-derived infections (DDIs) remain an unfortunate complication of transplantation. A major clue to early diagnosis is the timing of presentation. Tickborne DDIs will usually present as nonspecific febrile illness within the first 4 weeks after transplant. Infectious workup should be guided by knowledge of endemic infections in the donor’s as well as the recipient’s locale. Donors from endemic areas of vector-borne illnesses must be carefully screened by a detailed history and physical examination including appropriate laboratory tests and communication of the presence of ticks or suspicious skin lesions. Among recipients, when there is a high index of suspicion in symptomatic patients, early empiric antibiotics, such as doxycycline, for tickborne DDIs (doxycycline) can potentially improve outcome while diagnostic studies are pending [6]. Communication between transplant centers using organs from a common donor is of paramount importance. This aids in early detection and treatment of DDIs in other recipients. Further research is still needed to define the ideal screening strategies to minimize DDIs from vector-transmitted pathogens.

Notes

Acknowledgments. The authors thank C. Cherry and C. Paddock of the Centers for Disease Control and Prevention and Peter Weiner from Saint Barnabas Medical Center infectious disease department for their time, effort, and expertise.

Financial support. No authors have any funding to disclose with regard to this case series.

Potential conflicts of interest. V.D. reports receiving grants from National Institute of Allergy and Infectious Diseases (NIAID), National Institute of Diabetes and Kidney Diseases (NIDDK), and CareDx to their institution; consulting fees from Atara Bio; payment or honoraria from CareDx; and unpaid positions as a board of directors’ member for NAPRTCS, Section of Nephrology Chair for American Academy of Pediatrics, and National Governing Council for American Society of Pediatric Nephrology. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.