Selective impairment of CD43-mediated T cell activation in the Wiskott-Aldrich syndrome.

The Wiskott-Aldrich syndrome (WAS) is associated with defective glycosylation and altered membrane expression of the leukocyte sialoglycoprotein CD43. To investigate whether such modifications of CD43 are relevant to T cell dysfunction in WAS, we have analyzed peripheral blood mononuclear cells from WAS patients for proliferative responses to both CD43-interacting and other T cell mitogenic stimuli. While patient lymphocytes proliferated in response to phytohaemagglutinin, concanavalin A, interleukin-2 and neuraminidase/galactose oxidase, no responses were elicited upon attempted triggering of the CD43 signalling pathway using periodate or anti-CD43 antibody. Cells from four of five patients with clinical profiles resembling, but not identical, to that of classic WAS also failed to respond to periodate or anti-CD43 antibody stimulation. These results indicate that the aberrant expression of CD43 on WAS lymphocytes is associated with selective impairment of CD43-induced T cell proliferation and that detection of this defect may be useful in the diagnosis of WAS and its variant forms.