Silent saboteur: parvovirus B19 (B19V) and its impact on refractory post-transplant anemia.

Introduction: Anemia is a common and multifactorial complication following kidney transplantation, significantly impacting patient morbidity and graft survival. Parvovirus B19 (B19V), a DNA virus targeting erythroid progenitor cells, is an increasingly recognized cause of refractory anemia in kidney transplant recipients (KTRs), but data from Indian populations remain sparse. Methods: This single-center case series evaluated 10 KTRs diagnosed with B19V infection at the Institute of Nephro Urology, Bengaluru, from January 2021 to February 2025. Inclusion criteria encompassed KTRs with persistent anemia unresponsive to routine correction, confirmed by positive polymerase chain reaction (PCR) for B19V and/or characteristic bone marrow findings. Clinical parameters, laboratory data, immunosuppression details, treatment, and outcomes were collected prospectively over a minimum 3-months follow-up. Treatment included reduction of immunosuppression, with adjunct intravenous immunoglobulin (IVIg) for non-responders, and use of erythropoiesis-stimulating agent Desidustat as adjunct treatment in all cases. Results: Among 117 transplant recipients, 8.5% developed B19V infection, with a median infection onset of 6 weeks (range 2-462 weeks). All (100%) presented with fatigue and hypoproliferative anemia (reticulocyte count < 1%). 30% patients also had leukopenia and thrombocytopenia. 60% patients required IVIg post-reduction of immunosupression, achieving hematologic recovery within 4 weeks. Eight patients needed packed red blood cell transfusions (range 1-8 units). Two patients succumbed to severe infections unrelated to B19V. Statistical analysis confirmed significant decline in hemoglobin (mean reduction 3.72 ±1.22 g/dL, Conclusion: Parvovirus B19 is an important yet treatable cause of refractory anemia in KTRs. Early diagnosis by PCR and tailored management incorporating reduction in immunosuppression and IVIg can result in favorable outcomes. Routine surveillance is not warranted, but targeted testing should be considered in refractory anemia cases, particularly in resource-limited settings. Further studies are needed to optimize therapeutic strategies and validate novel treatments such as Desidustat.