Microfilaria Infection Associated with Hemophagocytic Lymphohistiocytosis in a Renal Transplant Patient

Abstract

TRANSPLANTATION IMAGE A 27-year-old male live-related renal allograft recipient, on triple maintenance immunosuppression therapy with tacrolimus, azathioprine, and prednisolone, presented 7 years after transplant with complaints of dysuria and fever for 2 weeks. Urine culture showed Pseudomonas infection. He had bi-cytopenia initially in the form of anemia and leukopenia, which worsened to pancytopenia subsequently. Azathioprine was stopped. He had been treated with sensitive antibiotics without any clinical response and the fever persisted. In view of febrile neutropenia, he had been given antifungal liposomal amphotericin-B. During evaluation, bone marrow aspirates demonstrated hypocellular marrow with increased number of histiocytes, with many showing hemophagocytosis [Figure 1a], suggesting the diagnosis of hemophagocytic lymphohistiocytosis (HLH), which was also supported by the high-level of serum ferritin 1100 ng/ml and high triglyceride level (600 mg/dl). There was also evidence of microfilaria in bone marrow [Figure 1b] and peripheral blood. He was started on diethylcarbamazine citrate.Figure 1: (a) May Grunwald Giemsa stain of bone marrow aspirate showing histiocytes and hemophagocytosis (black arrow), and (b) Grunwald Giemsa stain demonstrating microfilaria in bone marrow (black arrow)HLH is a rare, life-threatening condition caused by excessive immune system activation. It can be triggered by infection, malignancy, autoimmune diseases, and immunosuppression associated with solid organ transplantation. It can occur in renal transplant recipients at risk of opportunistic infections. Our patient had a pseudomonal urinary tract infection, which can trigger HLH. However, the patient was on a sensitive antibiotic, ceftazidime-sulbactam plus polymyxin. Most parasitic infections in transplant recipients produce morbidities, not mortality. Parasitic infections such as malaria, toxoplasmosis, leishmaniasis, and strongyloidiasis rarely cause HLH. This patient resides in the endemic zone of filaria; microfilaria was detected in our patient’s peripheral blood and bone marrow. Renal transplant recipients may have multiple infections simultaneously, and the index patient remains unresponsive to anti-pseudomonal antibiotics, suggesting that microfilariae may be responsible for HLH in this patient, resulting in the patient’s casualty. To the best of our knowledge, filariasis has not been implicated so far in the causation of HLH, and it may be an incidental finding in our patient. However, there is an alarm for renal transplant patients living in the endemic zone of filariasis and adherence to the National Filaria Control Program needs to be encouraged. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest