Objective. Modification of antigens represents a trigger for the generation of autoantibodies. In the pathogenesis of rheumatoid arthritis (RA), citrullination of proteins has been shown to be a critical process, and the determination of antibodies against citrullinated antigens has been a diagnostic milestone. We undertook this study to determine whether antibodies to mutated and citrullinated vimentin (MCV) could serve as a diagnostic and prognostic marker for RA.Methods. We identified novel isoforms of human MCV in the synovial fluid of RA patients. The significance of these disease-related modifications was investigated by the analysis of autoantibody reactivities. In a group of 1,151 RA patients, the diagnostic significance and the prognostic value of an anti-MCV enzyme-linked immunosorbent assay (ELISA) were compared with that of an anti-cyclic citrullinated peptide (anti-CCP) ELISA.Results. In RA, sensitivities of 82% and 72% were calculated for the anti-MCV and anti-CCP assays, respectively. The specificity of both assays was comparable (98% and 96%, respectively). In followup analyses of 16 RA patients with moderate disease activity (mean Disease Activity Score in 28 joints [DAS28] of 2.72) and 26 RA patients with active disease (mean DAS28 of 5.07), disease stratification of RA was possible using the anti-MCV assay (P ‫؍‬ 0.0084). A significant correlation of anti-MCV antibodies with the DAS28 was documented (r ‫؍‬ 0.5334, P ‫؍‬ 0.0003), in 42 RA patients (n ‫؍‬ 427 antibody determinations at different time points).

Genome integrity is continuously challenged by the DNA damage that arises during normal cell metabolism. Biallelic mutations in the genes encoding the genome surveillance enzyme ribonuclease H2 (RNase H2) cause Aicardi-Goutières syndrome (AGS), a pediatric disorder that shares features with the autoimmune disease systemic lupus erythematosus (SLE). Here we determined that heterozygous parents of AGS patients exhibit an intermediate autoimmune phenotype and demonstrated a genetic association between rare RNASEH2 sequence variants and SLE. Evaluation of patient cells revealed that SLE-and AGS-associated mutations impair RNase H2 function and result in accumulation of ribonucleotides in genomic DNA. The ensuing chronic low level of DNA damage triggered a DNA damage response characterized by constitutive p53 phosphorylation and senescence. Patient fibroblasts exhibited constitutive upregulation of IFN-stimulated genes and an enhanced type I IFN response to the immunostimulatory nucleic acid polyinosinic:polycytidylic acid and UV light irradiation, linking RNase H2 deficiency to potentiation of innate immune signaling. Moreover, UV-induced cyclobutane pyrimidine dimer formation was markedly enhanced in ribonucleotide-containing DNA, providing a mechanism for photosensitivity in RNase H2-associated SLE. Collectively, our findings implicate RNase H2 in the pathogenesis of SLE and suggest a role of DNA damage-associated pathways in the initiation of autoimmunity.

Epidemiological, clinical and serological data of uranium miners with symptoms of connective tissue diseases (CTD) were collected during the control examinations for occupational lung diseases since 1975. Twenty eight definite (four or more ARA criteria) and 15 probable (2-3 ARA criteria) SLE were diagnosed. The estimated prevalence among heavily silica exposed uranium miners was up to 93 in 100,000. The only significant differences to nonexposed SLE patients were decreased frequency of arthritis and photosensitivity and the absence of anti-Sm and anti-U1-RNP antibodies. ANA were found in all definite SLE patients examined with the following specificities: anti-dsDNA (in 44.4%), & anti-Ro/SSA (in 55.6%, four cases together with anti-dsDNA) and anti-La/SSB (in 22.2%). The autoantibody profiles of patients with probable SLE were similar, but with a lower frequency of ANA, anti-dsDNA and anti-Ro/SSA. Middle to high-titred autoantibodies to dsDNA, Ro/SSA and La/SSB were detected in 3.2% uranium miners with no (N = 1229) and in 20.6% with some symptoms (one ARA criterion and/or two or more of other CTD typical symptoms, N = 68) of CTD development. We conclude, that the strong exposure to dust with a high content of silica may predispose to or initiate the development of SLE. The detection of SLE-typical antibodies in quartz dust-exposed miners may indicate a higher risk for the development of systemic autoimmune disease.

In a real-life population of patients with severe, refractory PM or DM, objective improvement was seen in the majority of patients with regard to CPK and lung function tests, and glucocorticoids could be reduced. In contrast to the subgroup with DM, where one cycle of RTX appeared sufficient, patients with anti-synthetase syndromes commonly experienced flares necessitating RTX re-treatment. Infections are of concern.