Hemophagocytic Lymphohistiocytosis Due to Donor-Derived Ehrlichia chaffeensis in a Kidney Transplant Recipient with Human Immunodeficiency Virus

Introduction: Hemophagocytic Lymphohistiocytosis (HLH) is a life-threatening syndrome caused by various factors, leading to inflammation, multiorgan failure, and death if untreated. We present a case of donor-derived Ehrlichia and secondary HLH in a kidney transplant recipient with well-controlled HIV. Case Description: A 41-year-old woman with well-controlled HIV and end-stage kidney disease due to hypertension and focal segmental glomerulosclerosis underwent deceased donor kidney transplantation. The donor had untreated hepatitis C virus (HCV), Serratia marcescens bacteremia, and Candida dubliniensis mitral valve endocarditis. The patient had an uneventful post-transplant recovery with a nadir creatinine of 1.5 mg/dl, completed prophylactic ciprofloxacin and fluconazole to prevent donor-derived infections, and HCV treatment was anticipated. On post-operative day 20, the patient presented with fever, hypotension, fatigue, back pain, and anorexia. Labs revealed acute kidney injury (creatinine 2.5 mg/dl), pancytopenia, a low HCV viral load (82 IU/ml), and an undetectable HIV viral load. The patient's condition rapidly deteriorated with altered mental status and hypoxic respiratory failure. Despite no signs of hemolysis, HLH was suspected based on elevated ferritin level (>33,520 ng/ml) and confirmed by bone marrow biopsy. After ruling out other secondary causes of HLH, treatment with Dexamethasone was started. While awaiting approval for HCV therapy, we were notified that the mate kidney recipient tested positive for Ehrlichia chaffeensis and thus, empiric doxycycline was initiated. PCR testing of the patient’s serum and bone marrow was positive for Ehrlichia. The patient rapidly improved with doxycycline therapy and remained asymptomatic with good allograft function (creatinine 1 mg/dl) by the 3 month follow-up. Discussion: Ehrlichia chaffeensis is a rare cause of HLH with high mortality, requiring high suspicion for rapid diagnosis and intervention. Donor-derived infections should be considered in all recent transplant recipients with febrile illness. Ehrlichia, in particular, should be on the differential in those with HLH and when epidemiologic risk factors are present.