| Abstract: | In the present study 5 patients with common variable hypogammaglobulinemia (CVH) and 4 patients with selective IgA deficiency (IgA-D) were analyzed for the cellular defects responsible for impaired Ig synthesis with use of peripheral blood lymphocytes stimulated with either PWM or EBV in vitro. By the use of co-culture with PWM, all the patients examined had intrinsic B cell defects restricted to the synthesis of Ig class corresponding to the low or absent Ig class(es) in the sera. Two types of excessive suppressor T activity were found, which were abrogated by irradiation. One was isotype-nonspecific and the other was IgA-specific. Moreover, failure of IgA-specific helper T activity was demonstrated. The use of EBV as an agent that polyclonally activates B cells independently of T cells and monocytes should allow a clearer delineation of the level of the B cell defects. When co-cultured with EBV, B cells from 3 patients with CVH produced normal to subnormal quantities of IgM although they could produce no IgM upon co-culturing with normal T cells and PWM. B cells from 2 patients with CVH could produce IgM normally by stimulation with either PWM or EBV; however, there was no restoration to produce IgG or IgA in these patients. In addition, B cells from 2 patients with IgA-D produced not only IgG and IgM but also IgA almost normally at 4 days after in vitro stimulation with EBV. |
