Complement C3 polymorphism is associated with the susceptibility of myasthenia gravis in Chinese adult patients.

Complement component 3 (C3) had been proved to be involved in the pathogenesis and exacerbation of both myasthenia gravis (MG) patients and experimental autoimmune myasthenia gravis (EAMG) models. We evaluated the underlying association between five SNPs (rs344555, rs7951, rs3745568, rs366510 and rs163913) in C3 gene and Chinese adult MG patients. Our study consisted of 409 adult MG patients and 487 healthy controls. Subgroups were classified by gender, onset age, thymoma, anti-AChR antibody, onset muscle involvement (ocular/generalized) and severity (Oosterhuis score at the maximal severity during the initial two years after the onset of MG). We found significant differences in allele frequencies between MG and the control group, between various MG subgroups and the control group in rs344555 and rs3745568. There were significant differences in genotype frequencies between MG group and the control group, between MG subgroups and the control group under the codominant and additive inheritance models in rs344555 and rs3745568. No association was found between the frequencies of these SNPs and the severity of MG. We also used a comprehensive classification which was close to the clinical scenario to minimize the interaction among clinical features. In rs344555, the T allele frequency in thymoma (-) AChR-Ab (+) subgroup was significantly higher than that in the control group. Our results indicated that rs344555 was associated with the susceptibility of Chinese adult MG patients; rs3745568 was probably associated with the susceptibility of Chinese adult MG patients. No association was found between the frequencies of these SNPs and the severity of MG.

IL-4Rα Polymorphism Is Associated With Myasthenia Gravis in Chinese Han Population.

Interleukin-4 (IL-4) is a potent growth and differentiation factor for B cells which play a vital role in the pathogenesis of myasthenia gravis (MG). IL-4 exerts its function by binding to three types of IL-4 receptor (IL-4R) complexes. IL-4Rα is the key component of the IL-4R complex. We hypothesize that polymorphism of IL-4Rα gene may be associated with the susceptibility and severity of MG. A Chinese cohort of 480 MG patients and 487 healthy controls were recruited. Polymorphisms of IL-4Rα gene were determined with SNPscan™ methods and compared between MG and control groups, as well as among MG subgroups. Rs2107356 and rs1805010 were found to be associated with adult thymoma associated MG, and rs1801275 was found to be associated with adult non-thymoma AChR-Ab positive MG. We did not found association between IL-4Rα polymorphism and the severity of MG. Genetic variations of IL-4Rα were found associated with the susceptibility of MG in Chinese Han population.

Modulation of mitogen­activated protein kinase attenuates sepsis­induced acute lung injury in acute respiratory distress syndrome rats.

Sepsis is the most important predisposing cause inducing acute respiratory distress syndrome (ARDS); however, the mechanism of sepsis leading to the development of ARDS remains to be elucidated. Suppression of the mitogen­activated protein kinase (MAPK) signal by blocking the phosphorylation of Jun N­terminal kinase (JNK) and p38 in lung tissues could alleviate acute lung injury induced by sepsis. MAPK signaling may have a crucial role in development of the sepsis­induced acute lung injury. The specific inhibitors of JNK and p38 MAPK, SP600125 and SB203580, were administrated by intragastric injection 4 h before induction of ARDS after cecal ligation and puncture (CLP). Rats were sacrificed at 1, 6 or 24 h after CLP challenge. The histological evaluation, lung water content, and biochemical analysis were performed. The results revealed that the JNK and p38 MAPK inhibitor improved lung permeability, attenuated system inflammation, further alleviated the lung injury induced by sepsis. In conclusion, JNK and p38 MAPK signaling are essential for the development of ARDS following sepsis. Further studies are needed to illuminate the detailed mechanisms of JNK and p38 MAPK signaling in sepsis­induced ARDS.

Association study between IL-17A and IL-17F gene polymorphism and myasthenia gravis in Chinese patients.

Alleles of IL-17A and IL-17F genes were reported to be associated with many inflammatory and autoimmune disorders in Asian patients. Serum level and mRNA of IL-17A in peripheral blood mononuclear cells were reported to be significantly higher in MG patients than in healthy controls. In experimental autoimmune myasthenia gravis (EAMG) animals, IL-17 may have effects on the severity of MG. This study investigated the association between four SNPs of IL-17A and IL-17F gene (rs8193036, rs2275913 and rs3748067 in IL-17A; rs763780 in IL-17F) and MG in Chinese patients. The allele frequencies were compared between 480 MG patients and 487 healthy controls, between each MG subgroup and the control group, and between each pairs of MG subgroups. Subgroups were specified by clinical features (onset age, gender, thymoma, AChRAb and muscle involvement at onset) and maximal severity during the follow-up. No associations were found between the four SNPs of IL-17A and IL-17F gene and MG in Chinese patients.