Affected children are able to make some protective antibodies to certain organisms such as tetanus but are incapable of producing antibodies to other bacteria like Hemophilus influenzae or the pneumococcus. It is now known that a principal defect in the WAS B-lymphocyte system is an inability to make protective antibodies to any polysaccharide antigen. The T-lymphocyte system also has partial defects. T-lymphocytes are usually present in near normal numbers, but they function abnormally. In this case great caution must be exercised to prevent serious infections from developing.
Platelets are tiny blood cells that function to help prevent and stop bleeding.
In the WAS the platelet count in the blood is usually markedly reduced. In addition to having very few platelets, the platelets they do have are much smaller in size than normal platelets. In fact, the small platelet size is the best single test to confirm the diagnosis of WAS in a boy with thrombocytopenia. The WAS is the only known disease known to have tiny platelets. It may be very mild in some and severe in others.