Characterization of Herpesvirus saimiri-transformed T lymphocytes from common variable immunodeficiency patients.

SUMMARY Common variable immunodeficiency (CVID) is a very frequent but heterogeneous syndrome of anti- body formation. The primary defect remains unknown, but many reports describe peripheral blood T lymphocyte dysfunctions in a substantial proportion of CVID patients, which may impair T-B cell col- laboration. In order to investigate whether such putative defects were intrinsic to T cells or, rather, sec- ondary to quantitative differences in T cell subset distribution, or to other described disorders, we have used Herpesvirus saimiri (HVS) for the targeted transformation of CVID CD4 + and CD8 + T cells and subsequent functional evaluation by flow cytometry of their capacity to generate cell surface (CD154, CD69) or soluble (IL-2, TNF-a, IFN-g) help after CD3 engagement. Unexpectedly, the results showed that 40 different CVID blood samples exposed to HVS gave rise with a significantly increased frequency to transformed CD4 + T cell lines, compared to 40 age-matched controls (27% versus 3%, P £ 0·00002)