Familial defect of polymorph neutrophil phagocytosis associated with absence of a surface glycoprotein antigen (OKMI).

Two siblings with delayed separation of the umbilical cord, recurrent skin ulceration and dental sepsis were shown to have defective neutrophil phagocytosis of opsonized yeast (S. cerevisiae) and respiratory burst to opsonized and unopsonized zymosan. Increased activity in the NBT reduction test, normal ingestion and killing of S. aureus, and normal spontaneous and directional motility were also demonstrated. These abnormalities of neutrophil phagocytosis were confined to the affected siblings; their healthy parents and brother showed normal neutrophil function. Both children had a polymorph neutrophil leucocytosis, and had normal humoral and cell-mediated immunity. SDS electrophoresis of neutrophil cell membrane preparations showed absence of a glycoprotein band of 175,000 daltons, which was present in the parents' neutrophils in reduced amounts. OKMI monoclonal antibody, which recognized the C3bi receptor (CR3) failed to bind to the affected siblings neutrophils. The findings in these children emphasize the importance of this receptor in phagocytosis, and possibly other neutrophil functions.