Abnormalities of B cell subsets in patients with systemic lupus erythematosus.

The prototypic autoimmune disease, SLE, is known to be associated with polyclonal B cell hyperreactivity. Developing an understanding of the complex nature of human B cell differentiation, largely through the application of multiparameter flow cytometry to an analysis of circulating B cells has permitted an assessment of whether specific stages of B cell maturation are affected by the tendency for polyclonal B cell activation. Moreover, the analysis of perturbations of the specific stages of B cell maturation has generated new information on whether abnormalities in B cell differentiation are primarily involved in autoimmune disease immunopathology or, rather, are secondary to the inflammatory environment characteristic of subjects with this autoimmune disease. Multivariant analysis has begun to document abnormalities in B cell maturation that are primarily associated with lupus, or, alternatively related to disease duration, disease activity and concomitant medication. Together, these analyses have provided new insights on the role of B cell over-reactivity in SLE.