Auto-antibodies in Sjögren's syndrome. With special reference to liver-cell membrane antibody (LMA)

Sera from 70 patients with Sjogren's syndrome (SS), of whom 40 had primary and 30 secondary SS, were tested for various auto-antibodies of the IgG, IgA and IgM classes. 20% had liver-cell-membrane antibody (LMA), 90% had anti-nuclear antibodies (ANA), 40% salivary-gland antibodies (SGA), 13% anti-mitochondrial antibodies (AMA), 33% smooth-muscle cell antibodies (SMA), 9% skeletal-muscle antibodies (SKA) and only 1% had parietal-cell antibodies (PCA). In addition, 53% had IgM rheumatoid factor and 6 patients with anti-DNA antibodies all had SLE. 64% had increased serum IgG, 24% IgA and 14% IgM. A significantly higher incidence of ANA was found within all three Ig classes in patients with secondary SS. AMA and IgM-rheumatoid factor were also found to be elevated in this group. On the other hand, SGA occurred most frequently in patients with primary SS. LMA was mainly of the IgG class and IgG AMA and SMA were more often present in these patients than in those with a negative LMA reaction. The results of the investigation suggest inter alia that inflammatory liver disease, although not indicated by either the case history, physical examination or biochemical values, is probably present in patients with SS.