To investigate the expression of human cartilage glycoprotein 39 (HC gp-39) in peripheral blood mononuclear cells (PBMC) and synovium of rheumatoid arthritis (RA) patients.
Levels of HC gp-39 mRNA were detected by reverse transcription-polymerase chain reaction in PBMC of 31 patients with RA, 6 with osteoarthritis (OA), 10 with spondylarthropathy (SpA), 5 with systemic lupus erythematosus (SLE), and of 10 healthy controls. Levels of HC gp-39 mRNA were also detected in synovium of 7 patients with RA and 5 with OA. The expression of HC gp-39 was semi-quatificated by HC gp-39/tubulin ratio.
HC gp-39 mRNA expression in PBMC was increased in RA patients (the HC gp-39/tubulin ratio was 0.8690 +/- 0.5240), compared with OA (P = 0.024), SpA (P = 0.049), SLE (P = 0.043) and with healthy control subjects (P = 0.033). There were no statistically significant differences among OA, SpA, SLE and healthy controls. The level of HC gp-39 mRNA expression in RA synovium was also significantly higher than the level found in OA (P = 0.04).
HC gp-39 mRNA was obviously overrepresented in RA patients PBMC and synovium. These data support a possible pathogenic role of HC gp-39, as a candidate autoantigen, in the autoimmune response of RA.