Jónsson T, Thorsteinsson H, Arinbjarnarson S, Thorsteinsson J, Valdimarsson H
Department of Immunology, National University Hospital, Reykjavík, Iceland.
Ann Rheum Dis. 1995 Jul;54(7):578-81. doi: 10.1136/ard.54.7.578.
To evaluate the diagnostic and pathogenetic significance of IgA rheumatoid factor (RF) subclasses in rheumatoid arthritis (RA).
Rheumatoid factors of the IgA class and IgA1 and IgA2 subclasses were measured by enzyme linked immunosorbent assay in 58 patients with RA, 31 patients with other rheumatic diseases, 30 non-rheumatic individuals with increased concentrations of IgA RF, and in 100 randomly selected healthy controls.
Using a 95% cut off for the controls, 55% of the RA patients had increased total IgA RF, 64% IgA1 RF, and 60% IgA2 RF. RA patients with extraarticular manifestations more often had increased concentrations of IgA RF and both subclasses than patients without such manifestations (p < or = 0.01). Nearly all (31/32) RA patients with increased IgA RF had increases in both IgA RF subclasses, compared with 67% (20/30 of nonrheumatic symptom free individuals with increased IgA RF (p = 0.002).
Increased concentrations of the IgA2 RF subclass appears to be more specific for RA than increased IgA1 RF. Measurement of IgA RF subclasses may be clinically useful.
评估类风湿关节炎（RA）中IgA类风湿因子（RF）亚类的诊断及发病机制意义。
采用酶联免疫吸附测定法，对58例RA患者、31例其他风湿性疾病患者、30例IgA RF浓度升高的非风湿性个体以及100例随机选取的健康对照者，检测IgA类、IgA1和IgA2亚类的类风湿因子。
以对照组95%的临界值为标准，55%的RA患者总IgA RF升高，64%的患者IgA1 RF升高，60%的患者IgA2 RF升高。有关节外表现的RA患者比无此表现的患者更常出现IgA RF及其两个亚类浓度升高（p≤0.01）。几乎所有（31/32）IgA RF升高的RA患者，其IgA RF的两个亚类均升高，相比之下，IgA RF升高的无风湿症状个体中，这一比例为67%（20/30）（p = 0.002）。
IgA2 RF亚类浓度升高对RA似乎比IgA1 RF升高更具特异性。检测IgA RF亚类可能具有临床应用价值。
