類風濕性關節炎的各型類風濕因子

IgG rheumatoid factor (RF), IgM-RF, IgA-RF detected by ELISA in rheumatoid arthritis

本研究對50例類風濕性關節炎(RA)患者血清和關節液中各類型類風濕因子(RF )，包括IgG-RF、IgM-RF、IgA-RF；用酵素免疫吸附法(ELISA)進行測定，並與其他類型之風濕病症患者，包括退化性關節炎(OA)30例，系統性紅斑性狼瘡(SLE)32例，以及正常人40人進行對比。RA患者之血清中IgM-RF和IgG-RF皆顯著高於正常人和OA患者(P<0.001)。RA患者之IgA-RF－－雖高於OA(P<0.001)，但與正常人相比卻並無明顯差異(P>0.05)。RA患者血清中之IgM-RF和IgA-RF都高於SLE患者（P值分別小於0.01和0.001），但IgG-RF在RA和SLE卻未見差異(P>0.05)。RA患者之止清中IgM-RF、IgG-RF和IgA-RF之陽性率分別為90％、64％和46％，顯著高於正常人，OA患者以及SLE患者。至於關節液，RA患者之IgM-RF和IgA-RF顯著高於OA患者（P值分別小於0.001和0.02）；但在IgG-RF方面RA和OA患者之間則未見區別(P>0.05)，RA患者血清中各類型之RF分佈如下：IgM+IgG-RF最為常見(36％)，其次為IgM+IgG+IgA-RF(24％)，IgM+IgA-RF(18％)，僅4％為血清陰性。

Different isotypes of rheumatoid factor (RF), including IgG-RF, IgM-RF, and IgA-RF, in serum and synovial fluid were measured by the ELISA method in 50 cases of rheumatoid arthritis (RA) and compared to those with other arthritis: 30 cases of osteoarthritis (OA) and 32 cases of systemic lupus erythematosus (SLE), as well as 40 normal persons. Serum levels of IgM-RF and IgG-RF in RA patients were all significantly higher than those in normal persons and OA patients (P< 0.001), while IgA-RF was higher in RA when it was compared with OA (P< 0.001), but no difference was present among RA and normal persons (P< 0.05). The serum levels of IgM-RF and IgA-RF were higher in RA than SLE (P< 0.01 and 0.001 respectively), but showed no difference in IgG-RF (P> 0.05). The positive rate of IgM-RF, IgG-RF and IgA-RF in RA patients were 90%, 64% and 46% respectively, ehich were significantly higher than in normal persons and patients with OA or SLE. The synovial fluid levels of IgM-RF and IgA-RF were significantly higher in RA than in OA (P less than 0.001 and 0.02 respectively); but no difference was present among RA and OA in IgG-RF (P> 0.05). The distribution of RF isotypes in 50 patients of RA showed IgM+ IgG- RF was most frequent (36%) than IgM+ IgG+ IgA- RF (24%) and IgM+ IgA- RF (18%); only 4 percent of RA patients was seronegative.