Relationships between non organ-specific autoantibody production and age-related modifications of mononuclear cell phenotype.

13 autoantibodies were sought in 23-26 elderly people and in 47-118 young controls. We found at least one autoantibody (mainly rheumatoid factor, RF, and anti-nuclear antibodies in 17/23 elderly (i.e., 17%) and in 7/45 young controls (i.e., 16%). Autologous rosette-forming cells and Leu-7 positive cells (Natural Killer Cells?) were higher, and OKT4 and OKT8 positive cells lower in the former than in the latter group. We show that elderly have a high proportion of CD5 positive B cells, compared with young controls, following phorbol myristic acetate activation in vitro. This abnormality might account for the discrepancy in production of RF compared to other autoantibodies.