ANTIGEN PRESENTATION BY COMMON VARIABLE IMMUNODEFICIENCY (CVID) B-CELLS AND MONOCYTES IS UNIMPAIRED

CVID is a primary immunodeficiency syndrome comprising a heterogeneous group of patients with hypogammaglobulinaemia and defective formation of specific antibodies. Previous studies demonstrated defective T cel l responsiveness to antigen in a major subgroup of patients. In the pr esent study we investigated the capacity of peripheral blood monocytes and Epstein-Barr virus (EBV)-transformed B cell lines from seven pati ents with CVID, including two patients expressing an extended MHC hapl otype described to be associated with CVID, to present antigen (Tet. T ox.) to CD4(+) antigen-specific T cell lines from healthy controls. Th e results presented show an unimpaired capacity of peripheral blood mo nocytes to present antigen in all patients studied. In addition, the p resent study demonstrates for the first time that CVID B cells functio n normally as antigen-presenting cells (APC). These findings indicate that expression of a certain MHC phenotype in CVID is not associated w ith a defect in the presentation of recall antigen by monocytes and B cells. Based on these studies, uptake, processing and re-expression of recall antigen in association with MHC class II molecules on the APC surface are functional and there is no indication far structural abnor malities of the MHC class II molecules expressed by the patients studi ed that could be essential for their function in antigen binding and p resentation.