The role of PTPN22 in the pathogenesis of autoimmune diseases: A comprehensive review

The incidence of autoimmune diseases is increasing worldwide, thus stimulating studies on their etiopathogenesis, derived from a complex interaction between genetic and environmental factors. Genetic association studies have shown the PTPN22 gene as a shared genetic risk factor with implications in multiple autoimmune disorders. By encoding a protein tyrosine phosphatase expressed by the majority of cells belonging to the innate and adaptive immune systems, the PTPN22 gene may have a fundamental role in the development of immune dysfunction. PTPN22 polymorphisms are associated with rheumatoid arthritis, type 1 diabetes, systemic lupus erythematosus, and many other autoimmune conditions. In this review, we discuss the progress in our understanding of how PTPN22 impacts autoimmunity in both humans and animal models. In addition, we highlight the pathogenic significance of the PTPN22 gene, with particular emphasis on its role in T and B cells, and its function in innate immune cells, such as monocytes, dendritic and natural killer cells. We focus particularly on the complexity of PTPN22 interplay with biological processes of the immune system. Findings highlight the importance of studying the function of disease-associated PTPN22 variants in different cell types and open new avenues of investigation with the potential to drive further insights into mechanisms of PTPN22. These new insights will reveal important clues to the molecular mechanisms of prevalent autoimmune diseases and propose new potential therapeutic targets.     

Association between brain natriuretic peptide,markers of inflammation and the objective and subjective response to cardiac resynchronization therapy

Introduction: Studies suggest that cardiac resynchronization therapy (CRT) can induce a decrease in brain natriuretic peptide (BNP) and systemic inflammation, which may be associated with CRT-response. However, the evidence is inconclusive. We examined levels of BNP and inflammatory markers from pre-CRT implantation to 14 months follow-up in CRT-responders and nonresponders, defined by two response criteria. Methods: We studied 105 heart failure patients implanted with a CRT-defibrillator (68% men; age = 65.4 ± 10.1 years). The objective CRT-response was defined as a reduction of ⩾15% in left ventricular end systolic volume; subjective CRT-response was defined as an improvement of ⩾10 points in patient-reported health status assessed with the Kansas City Cardiomyopathy Questionnaire. Plasma BNP and markers of inflammation (CRP, IL-6, TNFα, sTNFr1 and sTNFr2) were measured at three time points. Results: Pre-implantation concentrations of TNFα were significantly lower for subjective responders compared to nonresponders (p = .05), but there was no difference in BNP and the other inflammatory markers at baseline. Objective CRT-response was significantly associated with lower BNP levels over time (F = 27.31, p < .001), and subjective CRT-response with lower TNFα levels (F = 5.67, p = .019). Conclusion: Objective and subjective response to CRT was associated with lower levels of BNP and TNFα, respectively, but not with other markers of inflammation. This indicates that response to CRT is not automatically related to a stronger overall decrease in inflammation. Large-scale studies are warranted that further examine the relation between the clinical effects of CRT on inflammatory markers, as the latter have been associated with poor prognosis in heart failure.     

Unveiling axial involvement in psoriatic arthritis: An ancillary analysis of the ASAS-perSpA study

ObjectiveTo determine the clinical profile of axial psoriatic arthritis (PsA) in a worldwide setting. Secondly, to identify factors associated with the development of axial involvement in patients with PsA.MethodsData from 3684 patients with axial spondyloarthritis (axSpA) or PsA from the ASAS-perSpA study were analysed. The ASAS-perSpA is a cross-sectional study that recruited consecutive patients with SpA (as diagnosed by their rheumatologist) from 68 centers worldwide and collected patient and disease data. First, 2651 axSpA patients and 367 PsA patients with any history of axial involvement (axPsA) were compared using logistic regression to later identify predictive factors for rheumatologist diagnosis of axPsA. Secondly, 367 axPsA patients were compared with 666 PsA patients lacking axial involvement (peripheral PsA [pPsA]) and the characteristics associated with axial manifestations were explored by logistic regression analysis.ResultsPatients with axPsA were older and less frequently males or HLA*B27 positive in comparison with axSpA patients. Additionally, while patients with axPsA had more peripheral manifestations and psoriasis, other extra-musculoskeletal manifestations (IBD and uveitis) were more frequent in those with axSpA. In the multivariable analysis, older age at diagnosis (OR = 1.04), peripheral arthritis (OR = 7.32) and dactylitis (OR = 2.82) were significantly associated with the diagnosis of axPsA. However, uveitis (OR = 0.22), IBD (OR = 0.12), HLA*B27 carriership (OR = 0.26) or sacroiliitis on imaging (OR = 0.5) were inversely associated with axPsA diagnosis as compared to axSpA. Axial involvement in patients with PsA was significantly associated with male gender (OR = 1.68), elevated CRP (OR = 2.87) and the absence of psoriasis (OR = 0.33).ConclusionIn this worldwide setting axPsA was defined by rheumatologists as a unique phenotype, with disease features lying between axSpA and pure pPsA.