Is agranulocytosis following infectious mononucleosis caused by autoimmunity?

A patient developed agranulocytosis after Epstein-Barr infection. Bone marrow examination revealed normal myelopoiesis with reduced mature neutrophil polymorphonuclear cells. IgG-specific antineutrophil antibodies (anti-HNA-1a) were found in serum and on polymorphonuclear cells, suggesting that the agranulocytosis after infectious mononucleosis was caused by an autoimmune mechanism.