Infectious mononucleosis with severe neutropenia and opsonic antineutrophil activity.

Severe granulocytopenia is an uncommon complication of infectious mononucleosis, only 18 cases having been reported previously. Our review and experience with this case would indicate that (1) severe granulocytopenia is usually diagnosed at about the third or fourth week of illness, (2) bone marrow examination most commonly reveals lack of mature neutrophil precursors in the myelocytic series, (3) the duration of usually short, lasting about a week, and (4) most patients recover without treatment. The laboratory findings in our case suggests that the neutropenia may be antibody mediated.