Postrenal transplant hemophagocytic lymphohistiocytosis and thrombotic microangiopathy associated with parvovirus b19 infection.

Persistent anemia is a known consequence of Parvovirus B19 (B19) infection following renal transplantation. However, to date, no description of B19-related hemophagocytic lymphohistiocytosis (HLH) exists in renal transplant recipients. We report a 24-year-old male kidney recipient, who presented with fever, severe anemia and allograft dysfunction two years following transplantation. Hyperferritinemia, hypertriglyceridemia, elevated serum lactate dehydrogenase, pancytopenia and fragmented red blood cells on the peripheral blood were also noted. Bone marrow examination revealed giant pronormoblasts and frequent histiocytes with intracellular hematopoietic elements, consistent with HLH. Renal allograft biopsy revealed closure of the lumen of glomerular capillaries and thickening of the capillary walls compatible with thrombotic microangiopathy. The presence of anti-B19 IgM antibody and viral DNA in the patient's serum (detected by real-time PCR) confirmed an acute B19 infection. Following high-dose intravenous immunoglobulin therapy, the anemia gradually resolved and renal function improved. As far as we know, this is the first report of B19-associated HLH and thrombotic microangiopathy in a renal transplant recipient.