The Wiskott‐Aldrich syndrome: studies of platelets, basophils and polymorphonuclear leucocytes

Summary Platelets, basophils and neutrophils from a patient with the Wiskott Aldrich syndrome (WAS) were exposed to stimuli that activate specific membrane receptor or directly initiate biochemical events (e.g. the Ca 2+ ionophore A23187 and ionomycin or arachidonic acid). Platelets from this patient did not aggregate in response to ADP, collagen, thrombin or adrenaline, which activate specific membrane receptors. Platelet aggregation, however, was normal in response to compound A23187, ionomycin or exogenous arachidonic acid. Histamine release from basophils of the WAS patient was normal in response to anti‐IgE, a formylated peptide (f‐met peptide), and to A23187. Similarly, the release of the lysosomal enzymes, β‐glucuronidase and lysozyme, from neutrophils of the WAS patient in response to serum treated zymosan (Zx), f‐met peptide, and A23187 was not significantly different from that of his parents and 13 normal donors. These results suggest that the primary defect in WAS is selectively present in platelets and is located in a biochemical step between receptor activation and Ca 2+ influx and/or initiation of arachidonate metabolism.