EXPRESSION OF CD5 AND CD72 ON T-CELL AND B-CELL SUBSETS IN RHEUMATOID-ARTHRITIS AND SJOGRENS-SYNDROME

A minority of B cells express the CD5 marker, which is found on virtua lly all T cells, and CD72 has been defined as the CD5 ligand on the B cell membrane. The mean fluorescence intensity (MFI) of the CD5 molecu les was shown to be higher on CD4+CD29+ than CD4+CD45RA+ in peripheral blood (PB) and synovial fluid (SF) of rheumatoid arthritis (RA) patie nts (P < 0.0001 and < 0.001), and PB of Sjogren's syndrome (SS) patien ts and normal controls (P < 0.02 and < 0.03). This MFI declined once t he CD4 expressed HLA-DR in PB of SS patients (P < 0.004) and normal co ntrols (P < 0.02) or CD25 in PB of RA (P < 0.004) and SS patients (P < 0-0004). There was a correlation between the CD5 MFI on CD4+ CD45RA and CD4+CD29 + in RA (P < 0-00 1) as well as SS (P < 0.0007) PB. The CD72 MFI was impressively higher on CD5+ than CD5- B cells in PB and S F of RA patients (P < 0.0001 and P < 0-005) and PB of SS patients (P < 0-005) and normal controls (P < 0.005). Our data suggest that, in ass ociation with CD4CD29, CD5 is involved in CD5+B/CD5+ B cell interactio ns in non-organ-specific autoimmune diseases.