Interferon regulatory factor 5 is a potential target of autoimmune response triggered by Epstein-barr virus and Mycobacterium avium subsp. paratuberculosis in rheumatoid arthritis: investigating a mechanism of molecular mimicry.

OBJECTIVES: Rheumatoid arthritis (RA) is a chronic disease characterised by a pro-inflammatory cytokines linked erosive joint damage and by humoral and cellular response against a broad range of self-peptides. Molecular mimicry between Epstein-Barr virus (EBV), Mycobacterium avium subsp. paratuberculosis (MAP) and host peptides has long been regarded as an RA pathogenetic mechanism. Using bioinformatic analysis we identified high sequence homology among interferon regulatory factor 5 (IRF5), EBV antigen BOLF1 and MAP antigen MAP_4027. Our objective was to evaluate the presence in sera of RA patients of antibodies (Abs) directed against human homologous IRF5 cross-reacting with BOLF1 and MAP_4027. METHODS: Frequency of reactivity against IRF5424-434, BOLF1305-320 and MAP_402718-32 was tested by indirect ELISA in sera from 71 RA patients and 60 healthy controls (HCs). RESULTS: RA sera show a remarkable high frequency of reactivity against IRF5424-434 in comparison to HCs (69% vs. 8%; p<0.0001). Similarly, seroreactivity against BOLF1305-320 was more frequently detected in RA sera than in HCs counterpart (58% vs. 8%; p<0.0001). Frequency of Abs against MAP_402718-32 was 17% in RA sera vs. 5% in HCs with a p-value at the threshold level (p<0.051). Prevalence of Abs against at least one of the assessed epitopes reached 72% in RA patients and 15% among HCs. Levels of Abs in RA patients were significantly related to systemic inflammation. CONCLUSIONS: IRF5 is a potential autoimmune target of RA. Our results support the hypothesis that EBV and MAP infections may be involved in the pathogenesis of RA, igniting a secondary immune response that cross-reacts against RA self-peptides.

Antiphospholipid syndrome nephropathy (APSN) in patients with lupus nephritis: a retrospective clinical and renal pathology study.

Data about clinical-laboratory features and outcome of antiphospholipid syndrome nephropathy (APSN) in the course of lupus nephritis (LN) are scarce. To determine prevalence, clinical correlations and outcome of APSN in patients with LN, retrospective analysis of renal specimens and review of medical records from 48 LN patients were performed. APSN was found in 12/48 (25 %) of LN. Positivity for lupus anticoagulant (LAC) and double antiphospholipids positivity [LAC plus anticardiolipin (aCL)] were significantly more frequent in APSN-LN (p = 0.02 and p = 0.01, respectively) than in LN, while single aCL positivity was not. Overt antiphospholipid syndrome appeared more frequent in patients with APSN-LN (p = 0.05). There were no statistically significant differences between APSN-LN and LN in the proportion of each World Health Organization class of LN (with the exception of a trend toward fewer Class III LN in APS-LN) and in the systemic lupus erythematosus (SLE) disease duration and severity. At the time of renal biopsy, patients with APSN-LN had median serum creatinine levels significantly higher than patients with LN [1.45 (0.6-6.6) vs. 1.00 (0.7-3.0), p = 0.02]. Double antiphospholipid positivity was the only variable significantly associated with APSN-LN at multivariate regression analysis (OR 8, 95 % CI 1.7-37, p = 0,008). APSN-LN and LN did not differ significantly as regards the rate of complete (25 vs. 19.4 %, p = 0.72) and partial treatment response (25 vs. 29 %, p = 0.82) at 6 months and the progression to end-stage renal disease after a median follow-up of 8.1 ± 3.6 years (16.6 vs. 13.8 %, p = 0.82). APSN was demonstrated in a quart of LN, appeared to be independent from underlying LN class and SLE severity, and did not seem to confer a worse prognosis to LN. The findings of higher creatinine and more interstitial fibrosis in APSN should be confirmed in future prospective larger studies.

Rheumatoid arthritis patient antibodies highly recognize IL-2 in the immune response pathway involving IRF5 and EBV antigens.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by a progressive joint damage due to largely unknown environmental factors acting in concert with risk alleles conferring genetic susceptibility. A major role has been attributed to viral infections that include past contacts with Epstein-Barr virus (EBV) and, more recently, to non-protein coding sequences of human endogenous retrovirus K (HERV-K) integrated in the human genome. Molecular mimicry between viral and self proteins is supposed to cause the loss of immune tolerance in predisposed hosts. There are evidences that anti-IL-2 antibodies (Abs) are present in subjects affected by autoimmune diseases and may be responsible for alterations in regulatory T cell responses. In this study, we evaluated the levels of Abs against IL-2, viral epitopes and interferon regulatory factor 5 (IRF5) in 140 RA patients and 137 healthy controls (HCs). Ab reactivity reached the highest levels for IRF5, EBV and IL-2 (56%, 44% and 39%, respectively) in RA with significantly lower values among HCs (7-9%, p < 0.0001), which suggests a possible cross-reaction between IRF5/EBV homologous antigens and shifts in T cell balance disrupted by anti-IL-2 Abs.

Asymmetric dimethylarginine and arterial stiffness in patients with rheumatoid arthritis: A case-control study.

OBJECTIVE: To investigate whether levels of asymmetric dimethylarginine (ADMA), as a measure of endothelial dysfunction, are higher in patients with rheumatoid arthritis compared with healthy control subjects. The relationships between ADMA and surrogate measures of arterial stiffness were evaluated. METHODS: Patients with rheumatoid arthritis and healthy control subjects were recruited. ADMA was quantified via enzyme-linked immunosorbent assay. Arterial stiffness was evaluated using pulse wave analysis. RESULTS: There was no significant difference in plasma ADMA concentration between patients with rheumatoid arthritis (n = 30) and healthy controls (n = 30). Aortic augmentation pressure was significantly higher in patients than in controls. C-reactive protein and Health Assessment Questionnaire score were independent predictors of arterial stiffness in patients. There was no relationship between ADMA concentration and aortic augmentation pressure in the study population as a whole. CONCLUSIONS: Arterial stiffness appears to be increased in rheumatoid arthritis and independently associated with systemic inflammation and physical disability. ADMA concentration was not increased in this small group of patients with rheumatoid arthritis compared with healthy controls; nor was it associated with arterial stiffness.

Squamous-cell carcinoma of the tongue following therapy of rheumatoid arthritis with abatacept.

KEY CLINICAL MESSAGE: A patient affected by rheumatoid arthritis developed a squamous-cell carcinoma probably due to abatacept, according to Naranjo algorithm. The case describes this adverse reaction for the first time and highlights the need for additional studies to establish the long-term risk profile of abatacept.