Functional properties of CD8 positive lymphocyte subsets in systemic lupus erythematosus.

CD8+ lymphocytes comprise several cell subpopulations that differ phenotypically and functionally. Although the percentage of T cytotoxic/suppressor cells (CD3+ CD8+) is usually increased in patients with active SLE, these lymphocytes are unable to suppress immunoglobulin (Ig) synthesis. However, freshly prepared lymphocytes from patients with SLE contain CD8+ DR+ cells which spontaneously suppress lymphocyte production of mitogen induced interleukin 2 (IL-2). Furthermore, CD8+ Leu 11+ non-T cells which comprise only 5% of total lymphocytes are also potent suppressors of IL-2 production. At the present time it is not known whether CD8+ suppressors of Ig synthesis and CD8+ suppressors of IL-2 production represent different maturation stages of common precursor cells or represent true heterogeneity of CD8+ lymphocytes.