CD4+T cells are crucial in achieving a regulated effective immune response to pathogens. Naive CD4+T cells are activated after interaction with antigen-MHC complex and differentiate into specific subtypes depending mainly on the cytokine milieu of the microenvironment. Besides the classical T-helper 1 and T-helper 2, other subsets have been identified, including T-helper 17, regulatory T cell, follicular helper T cell, and T-helper 9, each with a characteristic cytokine profile. For a particular phenotype to be differentiated, a set of cytokine signaling pathways coupled with activation of lineage-specific transcription factors and epigenetic modifications at appropriate genes are required. The effector functions of these cells are mediated by the cytokines secreted by the differentiated cells. This paper will focus on the cytokine-signaling and the network of transcription factors responsible for the differentiation of naive CD4+T cells.

BackgroundThe etiology of inflammatory bowel disease (IBD) is not clear and cytomegalovirus (CMV) infection is often associated with IBD patients. The etiologic link between IBD and CMV infection needs to be studied. The objective of the present study is to investigate the prevalence and risk factors of CMV in a cohort of IBD patients from Central China.MethodsTwo hundred and twenty six IBD patients (189 ulcerative colitis (UC) and 37 patients with Crohn’s disease (CD)), and 290 age and sex matched healthy controls were recruited. CMV DNA was detected by nested PCR, while serum anti-CMV IgG and anti-CMV IgM was determined by ELISAs. Colonoscopy/enteroscopy with biopsy of diseased tissues and subsequent H&E stain were then conducted in IBD patients with positive anti-CMV IgM. Finally, we analyzed the prevalence and clinical risk factors of CMV infection in IBD patients.ResultsThe prevalence of CMV DNA and anti-CMV IgG positive rate in IBD patients were 84.07% and 76.11%, respectively, higher than those in healthy controls (59.66% and 50.69%, respectively, P < 0.05), However, anti-CMV IgM positive rate was no different with healthy controls (1.77% vs 0.34%, P = 0.235). In univariate analysis of risk factors, the recent use of corticosteroid was associated with increase of CMV DNA and IgM positive rate in UC (P = 0.035 and P = 0.015, respectively), aminosalicylic acid drug therapy was correlated with positivity of CMV DNA and IgG in UC and CMV DNA in CD (P = 0.041, P < 0.001 and P = 0.014, respectively), the treatment of immunosuppresent was correlated with CMV IgM (P < 0.001). Furthermore, patients with severe UC were significantly associated with CMV DNA and IgM (P = 0.048 and P = 0.031, respectively). Malnutrition (albumin < 35 G/L) was also found to be related with CMV recent infection (P = 0.031). In multivariate analysis of risk factors in UC, pancolitis was significantly associated with CMV DNA positivity (P = 0.001). Severe UC and pancolitis seemed to be related with IgG positivity. For CD, there was just single factor associated with CMV positive in each group, multivariate analysis was unnecessary.ConclusionsCMV positive rate in IBD patients was significantly higher, than in healthy controls. The use of aminosalicylic acid, corticosteroid, immunosuppressants, pancolitis and severe IBD patients seemed to be more susceptible to CMV infection in univariate analysis of risk factors. However, no risk factor was found to be significantly correlated with CMV infection in multivariate analysis of risk factors.

T-SPOT.TB is a valuable assay in differentiating ITB from CD, particularly in the diagnostic exclusion of ITB based on its high specificity and NPV.