Youinou P, Mackenzie L, Jouquan J, Le Goff P, Lydyard P M
Ann Rheum Dis. 1987 Jan;46(1):17-22. doi: 10.1136/ard.46.1.17.
CD5 molecules present on human T cells are detectable but weakly expressed on some human B cells. We have increased the sensitivity of their detection by treating the B enriched cells with phorbol myristic acetate (PMA), a tumour promoting agent. The numbers of CD5+ B cells in the blood of patients with rheumatoid arthritis (RA) were higher than in control blood, and after PMA treatment this was statistically significant. CD5+ B cells were also increased in tonsils, lymph nodes, and spleens after PMA activation. There were no significant differences between the percentages of B cells carrying chi or lambda light chains in their expression of CD5 molecules in patients with RA.