Serum suppressive factors may account for the reduced polymorphonuclear cell function in haemophilia.

Haemophiliacs exhibit a broad range of immune defects. In this regard we have investigated the functional capacity of purified polymorphonuclear (PMN) cell suspensions in a group of Human Immunodeficiency Virus (HIV)+ or HIV- patients. Our results provide evidence for a significant reduction of PMN-mediated chemotactic responsiveness, phagocytosis and killing in haemophiliacs regardless of HIV infection. The depressed response does not reflect a PMN intrinsic dysfunction, since respiratory burst activity and lysosomal enzyme release from haemophilic PMN are unaffected in comparison to healthy donors. Quite interestingly the pretreatment of PMN from normal donors with either HIV+ or HIV- haemophilic sera gives rise to a reduction of PMN activity. Moreover, the suppressive effect is abrogated by serum heat inactivation. Taken together, these findings indicate a role for serum suppressive factors in the imbalance of PMN functional capacity in haemophilia regardless of HIV infection.