Abstract
B cell abnormality in 13 patients with primary a/hypo-gammaglobulinemia were studied. Number of peripheral B cells was normal in 7 of 13 patients but very small in the remaining six patients.
In the first step, we established lymphoblastoid cell lines (LCL) by EB virus and evaluated immunoglobulin production by LCL. LCLs were established in 7 patients, whose number of peripheral B cells was normal. IgM dominant pattern of immunoglobulin production was seen in 6 of the 7 LCLs as LCLs from cord blood cells. These results suggested that the B cells of these patients were immature, like the B cells of cord blood. Only three LCLs could be established from the remaining 6 patients, whose number of peripheral B cells was very small. These three LCLs produced dominantly IgM, dominantly IgG and no immunoglobulin. Various B cell abnormalities were sugested, even when the number of peripheral B cells was very small.
Next, we purified B cells from 5 patients and evaluated B cell functions, such as activation, proliferation and differentiation by using SAC and IL 2. In this assay system, B cell abnormality was devided into three groups. We concluded that the abnormality was in the step of activation/proliferation by SAC in 1 patient, in the step of proliferation response by IL 2 in 1 patient and in the step of differentiation to Ig secreting cell by IL 2 in 2 patients. B cells from 1 patient, whose LCL secreted IgG and IgM equally, showed no abnormality even in this assay.
Finally, we examined DNA and mRNA of immunoglobulin of the LCL, which produced no immunoglobulin. It was confirmed that the LCL was pre B cell line, and suspected that μm-RNA of the LCL had an abnormality because the number of M. W. was small compared to that of control LCLs secreting IgM.
