title: Induction of excessive B cell proliferation and differentiation by an in vitro stimulus in culture in human systemic lupus erythematosus.
abstract: B cell hyperactivity present in the body in patients with systemic lupus erythematosus (SLE) can be detectable via almost any measure of B cell function. Nonetheless, the basis for the B cell hyperactivity is difficult to study in vitro. In this study, we have obtained the resting B cells from patients with entirely inactive SLE by collecting them sedimenting in a high density fraction on a Percoll density gradient. These resting SLE B cells proliferated in vitro at a higher rate than normal B cells when exposed to Staphylococcus aureus Cowan I (SAC). In addition, significant proliferation was observed earlier in the course of culture in SLE patients than in normal controls. Moreover, the SLE resting B cells, once triggered by SAC produced abnormally high numbers of immunoglobulin-secreting cells in response to T cell-derived soluble factors. There was less frequency of circulating Leu 1+ B cells in the SLE patients than in normal controls. Moreover, not only Leu 1+ B cells but also Leu 1- B cells of SLE patients were more responsive to SAC than those of normal controls. The results indicate that the B cell hyperactivity in human SLE can be induced by in vitro stimuli, and may not be limited to the Leu 1+ B cell subset.
authors.affiliation: Department of Internal Medicine, Shimane Medical University, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Sakane
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D002454:Cell Differentiation; D002455:Cell Division; D002469:Cell Separation; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D013211:Staphylococcus aureus / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D000944:Antigens, Differentiation, B-Lymphocyte; D007136:Immunoglobulins