Circulating IgA- and IgM-rheumatoid factors in patients with primary Sjögren syndrome. Correlation to extraglandular manifestations.
IgM- and IgA-rheumatoid factors (RF) were determined by ELISA technique in 40 consecutive patients with primary Sjögren syndrome (primary SS), all fulfilling the Copenhagen diagnostic criteria. Increased concentrations of IgM-RF were found in 25 patients (63%) (median concentration: 85 IU/ml, range 11-302 IU/ml). Increased concentrations of IgA-RF were found in 22 of the patients (55%) (median concentration: 100 AU/ml, range 25-255 AU/ml). The levels of IgM- and IgA-RF were closely correlated (r = 0.82, p less than 0.001). IgM-RF (p = 0.037), but not IgA-RF (p = 0.17), was significantly correlated to the presence of antinuclear antibodies (ANA). In contrast, IgA-RF (p = 0.002), but not IgM RF (p = 0.068), was significantly correlated to the presence of hypergammaglobulinemia. The most common extraglandular manifestations were: arthralgia/synovitis (60%), myalgia/myositis (28%), Raynaud's phenomenon (20%) and pulmonary manifestations (15%). Concentrations of both IgM-RF (r = 0.43, p less than 0.01) and IgA-RF (r = 0.57, p less than 0.001) were correlated to the number of extraglandular manifestations present in each patient.
Müller
K
K
Department of Rheumatology, Rigshospitalet, Copenhagen, Denmark.
Oxholm
P
P
Mier-Madsen
M
M
Wiik
A
A
D000328:Adult; D000368:Aged; D000974:Antibodies, Antinuclear / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006942:Hypergammaglobulinemia / Q000276:immunology; D007070:Immunoglobulin A / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D008171:Lung Diseases / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009220:Myositis / Q000276:immunology; D011928:Raynaud Disease / Q000276:immunology; D012189:Retrospective Studies; D012217:Rheumatoid Factor / Q000032:analysis*; D012859:Sjogren's Syndrome / Q000150:complications / Q000276:immunology*; D013585:Synovitis / Q000276:immunology
D000974:Antibodies, Antinuclear; D007070:Immunoglobulin A; D007075:Immunoglobulin M; D012217:Rheumatoid Factor