Basophil activation in idiopathic mixed cryoglobulinemia.

We studied basophil activation in patients affected by idiopathic mixed cryoglobulinemia in order to investigate the role of the basophil cell in the pathogenesis of the vasculitis typical of this disease. We selected 13 patients and we performed the in vitro basophil degranulation test with cryoprecipitate; in 5 cases the test was positive when it was performed in whole blood, while it was negative when it was performed with cells washed and resuspended in Tyrode's buffer. In 6 subjects it was not possible to perform the test because of the very low number of circulating basophil cells. Finally, in 2 subjects the in vitro basophil degranulation test with cryoprecipitate was negative; this result may be related to the very low levels of complement factors in the sera of these subjects. These findings suggest that the pathogenetic mechanism of vasculitis in idiopathic mixed cryoglobulinemia could be started by basophil activation.