The presence of anti-Fc gamma receptor autoantibodies is related to the clinical presentation of primary Sjögren's syndrome.
OBJECTIVE
Fc gamma receptor III (Fc gamma RIII) is one of the 3 structurally distinct families of receptors for the Fc domain of IgG, and its Fc gamma RIIIb isoform is exclusively expressed in polymorphonuclear (PMN) cells. We sought to detect anti-Fc gamma RIII autoantibodies in serum from patients with primary Sjögren's syndrome (SS).


METHODS
Sixty-six patients with SS and 44 healthy controls were enrolled in the study. ELISA were developed.


RESULTS
IgG and IgM autoantibodies were found in 16 (10 IgG+ IgM+ and 6 IgG+ IgM-) and 24 patients (10 IgG+ IgM+ and 14 IgG- IgM+) respectively. Their frequency was higher in patients with nonerosive arthritis (p < 0.02), Raynaud's phenomenon (p < 0.003), and lung involvement (p < 0.02) than in patients without such complications. The levels of IgM and IgG antibody (p < 0.05) correlated with the content of IgA without the circulating immune complex (IC), while there was no relationship between anti-Fc gamma RIII activity and the PMN count.


CONCLUSIONS
Anti-Fc gamma RIII autoantibodies may act as an acquired additional factor further compromising IC handling in individuals who share HLA-DR3 alloantigen.
Lamour
A
A
Department of Rheumatology, Brest University Medical School, France.
Le Corre
R
R
Pennec
Y L
YL
Youinou
P
P
D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007126:Immunoglobulin Allotypes / Q000032:analysis; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007136:Immunoglobulins / Q000276:immunology; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D017452:Receptors, IgG / Q000096:biosynthesis / Q000276:immunology*; D011994:Recombinant Proteins; D012217:Rheumatoid Factor / Q000097:blood; D012859:Sjogren's Syndrome / Q000276:immunology*; D018709:Statistics, Nonparametric
D001323:Autoantibodies; D006684:HLA-DR Antigens; D007126:Immunoglobulin Allotypes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; D017452:Receptors, IgG; D011994:Recombinant Proteins; D012217:Rheumatoid Factor