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Case 124 - Discussion

Hematopathology Case


Parvovirus Infection

  • Parvovirus B19 infection: humans the only known host, mostly self-limited with life-long immunity

  • Virus binds to blood group P antigen receptors

  • Clinical expression: erythema infectiosum in children (Fifth disease), arthralgias and arthritis in adults

  • Effect on hematopoiesis: healthy individuals - transient arrest of erythropoiesis with mild hemoglobin drop; patients with hemolytic disorder - transient aplastic crisis; immunocompromised individuals - pure red cell aplasia

  • Peripheral blood: normochromic normocytic anemia with reticulocytopenia that is resistant to erythropoietin therapy, normal WBC and platelet counts or varying degrees of cytopenia

  • Bone marrow: giant proerythroblasts (lantern cells) with fine megaloblastoid chromatin, loss of normal tinctorial quality, nuclear swelling with dissolution of the nucleus, prominent intranuclear inclusion.. Little maturation occurs beyond the proerythroblast. Myeloid and erythroid lineages are relatively normal.

Reference: AFIP, Non-Neoplastic Disorders of the Bone Marrow, series 4