Correlation of smooth-muscle and nuclear antibodies in normal subjects.
By means of the indirect immunofluorescent method the occurrence of smooth-muscle antibodies (SMA) was studied in 582 normal subjects of different ages, and the incidence of SMA was compared with that of anti-nuclear antibodies (ANA). SMA were detected in 32 (5-5%) and ANA in 28 (4-8%) of the normal subjects. The antibodies were of the IgG and the IgM class, while no IgA antibodies could be detected. IgM-SMA were demonstrated in 2-9%, IgM-ANA in 4-1% and IgG-ANA in 1-2% of the 582 subjects, and the incidence of these antibodies increased with increasing age (P = 0-012, P less than 0-001 and P = 0-003, respectively). IgG-SMA occurred in 3-6% and the prevalence of these antibodies was not age-related. No relationship between the incidence of antibodies and sex could be established. IgM-SMA and IgM-ANA were often found together in the same individuals (P = 0-002), which suggests that the same factors may elicit the formation of both antibodies.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000906:Antibodies / Q000032:analysis*; D000974:Antibodies, Antinuclear / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007223:Infant; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000276:immunology*
D000906:Antibodies; D000974:Antibodies, Antinuclear; D007074:Immunoglobulin G; D007075:Immunoglobulin M