Raju, Raghavan Pillai

Abstract Studies in myasthenia gravis (MG) patients demonstrate that polymorphism at the HLA-DQ locus influences the development of MG. Several studies using the mouse models also demonstrate the influence of class II molecules, especially the H2-A, which is the mouse homologue of HLA-DQ, in experimental autoimmune myasthenia gravis (EAMG). We used transgenic mice expressing two different DQ molecules, DQ8 (DQA1*0301/B1*0302) and DQ6 (DQA1*0103/B1*0601), to evaluate the role of HLA-DQ genes in MG. These mice do not express endogenous mouse class II molecules since they contain the mutant H2-Aβ0 gene. The mice were immunized with Torpedo acetylcholine receptor, and EAMG was assessed by clinical evaluation and was confirmed by electrophysiology. Clinical scores for EAMG were highest in HLA-DQ8 transgenic mice, whereas the scores of HLA-DQ6 mice rarely exceeded grade 1. There was no incidence of EAMG in class II-deficient (H2-Aβ0) mice. These results demonstrate that polymorphism at the HLA-DQ locus affects the incidence and the severity of EAMG. The manifestation of susceptibility to EAMG in the context of human class II molecules underscores the important roles of these molecules in the initiation and perpetuation of EAMG.

Abstract Low-grade inflammation associated with metabolic syndrome (MS) triggers alterations in several organs, but its effects on pulmonary functional and immunological response in older adults are unknown. This cross-sectional study investigated such responses in older adults with and without MS. The study consisted of 77 older adults with MS (68 ± 3 years old) and without MS (67 ± 3 years old). Impulse oscillometry (IOS) was used to evaluate airway and tissue resistance and reactance. Biomarkers of systemic and pulmonary inflammation and fibrosis were studied. Total resistance of respiratory system (R5Hz; p < 0.009), and resistance of proximal (R20Hz; p < 0.001) and distal (R5Hz-R20Hz; p < 0.004) airways were impaired in MS individuals compared to those without MS. The levels of pro-inflammatory (leptin; IL-1beta; IL-8, p < 0.001; TNF-alpha, p < 0.04) and pro-fibrotic (VEGF, p < 0.001) factor increased in MS, while reduced levels of anti-inflammatory cytokines (adiponectin; IL-1ra; IL-10; p < 0.001), and anti-fibrotic (relaxin 1; relaxin 3; Klotho, p < 0.001) factors were found. We conclude that MS accelerates lung function and mechanics impairment in older adults in detriment of an imbalance between pro and anti-inflammatory and fibrotic mediators. Furthermore, this study shows that the lungs also are a target organ in MS, deserving clinical assessment in older adults’ population.