Lymphocytes binding C-reactive protein and streptococcal membranes in acute rheumatic fever.

Peripheral blood lymphocytes binding CRP and streptococcal membrane antigens were studied in 19 patients with ARF with the use of a number of paired analyses for cell surface markers. A small fraction (6.9%) of T cells showed binding to streptococcal membrane. A large degree of overlap (38% to 46%) occurred in membrane-binding T cells and those with identifiable CRP. One third of T gamma cells showed CRP bindings, and approximately one quarter to T gamma cells in both ARF patients and normal controls showed membrane la antigen. A considerable concordance (50% to 75%) was noted between T cells binding streptococcal membrane and cells positive for la antigen. In contrast to T cells, B cells bearing CRP showed less overlap (mean 11%) with cells binding streptococcal membrane. Since B cells with concomitant surface immunoglobulin and la antigen constituted the major lymphocyte subpopulation binding streptococcal membrane antigens, relative exclusion of streptococcal membrane binding by B cells with surface CRP may represent natural protective modulation whereby proportions of potential antigen-binding B cells are defused by lymphocyte membrane CRP.