H. Ihn et al., Distribution and antigen specificity of anti-U1RNP antibodies in patients with systemic sclerosis, CLIN EXP IM, 117(2), 1999, pp. 383-387
Systemic sclerosis (SSc) is a generalized connective tissue disease which i
s characterized by the presence of several autoantibodies. To determine the
prevalence and antigen specificity of anti-U1RNP antibodies (anti-U1RNP) i
n patients with SSc, serum samples from 223 patients with SSc, 117 patients
with systemic lupus erythematosus (SLE), 18 patients with mixed connective
tissue disease (MCTD) and 40 healthy control subjects were examined by ind
irect immunofluorescent analysis (IIF), double immunodiffusion, and immunob
lotting using nuclear extract of HeLa cells. Eighteen of the 223 (8%) serum
samples from patients with SSc were shown to be positive for anti-U1RNP. T
he frequency of anti-U1RhTP positivity in limited cutaneous SSc (14%) was s
ignificantly higher than that in those with diffuse cutaneous SSc (3%). Ant
i-Sm antibodies were detected in patients with SLE positive for anti-U1RNP,
but not in those with SSc positive for anti-U1RNP or those with MCTD. Immu
noblotting demonstrated that anti-70-kD antibodies were detected more often
in patients with SSc positive for anti-U1RNP and in those with MCTD than i
n those with SLE. Furthermore, anti-U1RNP was closely correlated with pulmo
nary fibrosis and joint involvement in patients with SSc. These results sug
gest that anti-70-kD antibodies are useful in the classification of patient
s with anti-U1RNP.