B19 infection results in the specific inhibition of erythroid colony formation (no effect of other cells lines) lytically infects and subsequently kills the erythroid precursors production of IgM and IgG directed towards B19 results in: normoblasts and erythroid hyperplasia in the bone marrow reticulocytes to peripheral blood increased concentration of hemoglobin recurrence is rare due to the acquisition of lifelong B19 immunity after the first infection.