IgG autoantibodies by ELISA in IgM anti-CMV(+) versus IgM anti-CMV(-) patients. (a) IgG anti-U1RNP/Sm and IgG anti-U1snRNP-70 kDa protein (anti-U1–70 k) by ELISA. Anti-small nuclear ribonucleoprotein (Anti-snRNP) immunoprecipitation-positive sera (1:2,500 dilution, n = 7 for the IgM anti-cytomegalovirus (CMV)(+) group and n = 12 for the anti-CMV IgM(-)IgG(+) group) were tested for anti-U1RNP/Sm and U1–70 k antibodies by ELISA. (b) IgG anti-U1–70 k, P peptide, dsDNA, and anti-β2-glycoprotein I (anti-β2GPI) by ELISA. ELISAs were performed as described in Materials and methods using 1:500 diluted sera. For anti-U1RNP/Sm and U1–70 k, data from 1:2,500 diluted sera are shown.