High prevalence of autoantibodies against the nuclear high mobility group (HMG) protein SSRP1 in sera from patients with systemic lupus erythematosus, but not other rheumatic diseases.
OBJECTIVE
To evaluate the presence of autoantibodies to the high mobility group (HMG) structure specific recognition protein I (SSRP1) in sera from patients with systemic lupus erythematosus (SLE) or other rheumatic diseases.


METHODS
Antibodies to SSRP1(anti-SSRP1) were measured in sera from patients with SLE, Sjogren's syndrome (SS), ulcerative colitis (UC), systemic sclerosis (SSc), rheumatoid arthritis (RA), and sera from healthy individuals by both an enzyme-linked immunoassay (ELISA) and Western blotting (WB) using the recombinant SSRP1 N-terminus as antigen.


RESULTS
We found 28.8% of the sera from patients with SLE contained anti-SSRPI by both ELISA and WB assay, compared to 8.3% of the sera from healthy individuals. When the 40 sera from patients with other autoimmune diseases were tested, only 2 sera (5%) from individuals with SS showed a moderate reactivity to SSRPI in both ELISA and WB assays.


CONCLUSIONS
The results show that anti-SSRPI can be identified in sera from patients with SLE, but not with other rheumatic diseases and may thus help the diagnosis of SLE in the presence of appropriate clinical findings.
Santoro
Piera
P
From the Immunogenetics and Experimental Oncology Center, CNR, University of Turin, Italy.
De Andrea
Marco
M
Migliaretti
Giuseppe
G
Trapani
Claudio
C
Landolfo
Santo
S
Gariglio
Marisa
M
D000918:Antibody Specificity / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology*; D015153:Blotting, Western; D003093:Colitis, Ulcerative / Q000097:blood / Q000276:immunology; D004268:DNA-Binding Proteins / Q000276:immunology* / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006609:High Mobility Group Proteins / Q000276:immunology* / Q000378:metabolism*; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000175:diagnosis / Q000276:immunology*; D017434:Protein Structure, Tertiary / Q000502:physiology; D012595:Scleroderma, Systemic / Q000097:blood / Q000276:immunology; D012859:Sjogren's Syndrome / Q000097:blood / Q000276:immunology; D035602:Transcriptional Elongation Factors
D001323:Autoantibodies; D004268:DNA-Binding Proteins; D006609:High Mobility Group Proteins; C073537:SSRP1 protein, human; D035602:Transcriptional Elongation Factors