Senear-Usher syndrome or pemphigus erythematosus is a pathology that overlaps clinically and serologically with pemphigus foliaceus and lupus erythematosus. Skin biopsies of patients with pemphigus erythematosus reveal acantholysis and deposits of immunoglobulins in desmosomes, and they are positive in the lupus band test. In the present paper, we determined whether the autoantibodies associated with pemphigus erythematosus targeted a single antigen or multiple antigens as a result of the stimulation of independent B cell clones. Our present paper demonstrates that patients with pemphigus erythematosus produce both antiepithelial antibodies specific for desmoglein 1 and 3 and antinuclear antibodies specific for Ro, La, Sm, and double-stranded DNA antigens. After eluting specific anti-epithelial or anti-nuclear antibodies, which were recovered and tested using double-fluorescence assays, a lack of cross-reactivity was demonstrated between desmosomes and nuclear and cytoplasmic lupus antigens. This result suggests that autoantibodies in pemphigus erythematosus are directed against different antigens and that these autoantibodies are produced by independent clones. Given these clinical and serological data, we suggest that pemphigus erythematosus behaves as a multiple autoimmune disease.

Autoimmune nephritis triggered by metallic ions was assessed in a Long-Evans rat model. The parameters evaluated included antinuclear autoantibody production, kidney damage mediated by immune complexes detected by immunofluorescence, and renal function tested by retention of nitrogen waste products and proteinuria. To accomplish our goal, the animals were treated with the following ionic metals: HgCl2, CuSO4, AgNO3, and Pb(NO3)2. A group without ionic metals was used as the control. The results of the present investigation demonstrated that metallic ions triggered antinuclear antibody production in 60% of animals, some of them with anti-DNA specificity. Furthermore, all animals treated with heavy metals developed toxic glomerulonephritis with immune complex deposition along the mesangium and membranes. These phenomena were accompanied by proteinuria and increased concentrations of urea. Based on these results, we conclude that metallic ions may induce experimental autoimmune nephritis.

The present study investigated posttranslational reactions in the salivary glands of patients with Sjögren's syndrome. We analysed the biopsies of primary Sjögren's patients using immunohistochemistry and a tag-purified anticyclic citrullinated protein (CCP) antibody to detect citrullinated peptides, and the presence of peptidylarginine deiminase 2 (PAD2) was assessed simultaneously. The present work demonstrated the weak presence of the PAD2 enzyme in some normal salivary glands, although PAD2 expression was increased considerably in Sjögren's patients. The presence of citrullinated proteins was also detected in the salivary tissues of Sjögren's patients, which strongly supports the in situ posttranslational modification of proteins in this setting. Furthermore, the mutual expression of CCP and PAD2 suggests that this posttranslational modification is enzyme dependent. In conclusion, patients with Sjögren's syndrome expressed the catalytic machinery to produce posttranslational reactions that may result in autoantigen triggering.

Sjögren's syndrome is an autoimmune epithelitis of salivary and lachrymal glands that results in Sicca syndrome. Citrulline is synthesised by the conversion of ornithine to arginine during urea formation, exists as free citrulline produced by NOS enzymes, and another form produced by post‐translational modification of proteins at arginine residues by peptidylarginine deiminases (PADs), which is important in autoimmunity. We investigate post‐translational reactions in salivary gland biopsies from 24 patients with primary Sjögren's syndrome and 24 controls using immunohistochemistry and a tag‐purified anti‐cyclic citrullinated protein CCP antibody to detect citrullinated peptides, PAD2 also was assessed. The present work demonstrated the weak presence of the PAD2 in some normal salivary ducts (10%), although PAD2 expression was increased considerably in Sjögren's patients. The presence of citrullinated proteins in the salivary tissues of Sjögren's patients strongly supports the in situ post‐translational modification of proteins in this setting. The mutual expression of CCP and PAD2 (70%) suggests that this post‐translational modification is enzyme‐dependent. In conclusion, patients with Sjögren's syndrome expressed the catalytic machinery to produce post‐translational reactions that may result in auto‐antigen triggering.Grant: P/PIFI 2011–32MSU0017H‐06–01