[The hematological diversity of human parvovirus B19 infection after allo-hematopoietic stem cell transplantation in pediatric patients].

Objective: To retrospectively analyze hemogram and bone marrow characteristics of pediatric patients infected with parvovirus B19 (HPV-B19) after hematopoietic reconstitution following allo-hematopoietic stem cell transplantation. Methods: The clinical course of nine patients with HPV-B19 infection, including hemogram and bone marrow smear analysis during infection, were retrospectively analyzed. Results: Despite the hematological heterogeneity, all patients exhibited reduced hemoglobin levels accompanied by reticulocytes. The proportion and absolute count of reticulocytes decreased by 90.4% (24.7% -98.7% ) and 90.7% (18.6% -99.0% ) , respectively, in one week. Additionally, five patients manifested a decline in neutrophil granulocyte count in peripheral blood whereas granulocytic hypoplasia was not observed in bone marrow. Furthermore, six patients exhibited megakaryocytic hypoplasia in bone marrow, including five patients with decreased platelet counts in peripheral blood. Importantly, only some patients exhibited erythroid hypoplasia although all patients exhibited a decline in hemoglobin in peripheral blood. Erythroid hypoplasia in bone marrow was present in five patients. Conclusion: There was heterogeneity in hemogram and bone marrow smear characteristics among pediatric patients infected with HPV-B19 following allo-hematopoietic stem cell transplantation. Anemia accompanied by decreased reticulocyte count should prompt screening for HPV-B19 in these patients.