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.

• 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.

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