NORMAL SIALOPHORINE (CD43) EXPRESSION IN A THROMBOCYTOPENIC AND IMMUNODEFICIENT WOMAN CARRIER OF WISKOTT-ALDRICH SYNDROME

We report on a 24-year-old thrombocytopenic woman with a history of re current infections, skin and mucosal bleeding, and a member of a famil y with the Wiskott-Aldrich syndrome. Hemorrhagic complications occurre d at age 20, when mild peripheral thrombocytopenia (38-52 g/L) was con firmed. Four male family members died of infectious complications at a ges ranging from 6 months to 3 years. At the time of the study, she wa s free of infection. Physical examination exhibited ecchymoses of skin of the legs only, and her laboratory investigations demonstrated a la ck of secondary waves of platelet aggregation with adenosine diphospha te (ADP) and prolongation of the lag phase after collagen stimulation. Intensities of aggregation induced by ADP, collagen, and thrombin wer e decreased. Patient's plasma aggregating activity was diminished. Abn ormal intraplatelet malonylodialdehyde formation was also found. Asses sment of the platelet volume distribution demonstrated the presence of normal-size population. Examination of isolated platelets by electron microscope showed a reduced number of dense bodies. The content of me pacrine-labeled platelet bodies in the fluorescent microscopy study wa s also diminished. Immunological investigations revealed a slight decr ease in immunoglobulin G (IgG) serum concentration and a low isohemagg lutinin titer. Additionally, diminished percentages of T activated and total B cells were detected. Moreover, a slight increase of natural k iller cells was revealed. Lymphocyte surface sialophorin (CD43) expres sion was normal. Polymorphonuclear cell (PMN) phagocytosis, chemotaxis , spontaneous migration, intravascular polymorphonuclear granulocyte a ggregate number, and Fc IgG receptor expression study all showed no ab normalities. However, a reduced bactericidal capacity of the PMN, redu ced adhesion to albumin-covered plastic surfaces, and diminished resti ng superoxide/hydrogen peroxide production were found.