CC Chemokine Ligand 20 and Its Cognate Receptor CCR6 in Mucosal T Cell Immunology and Inflammatory Bowel Disease: Odd Couple or Axis of Evil?Chemokines and their cognate receptors have been identified as major factors initiating and governing cell movement and interaction. These ligands and their receptors are expressed on a wide variety of cells and act during steady-state migration as well as inflammatory recruitment. CCR6 is a non-promiscuous chemokine receptor that has only one known chemokine ligand, CCL20, and is present on B and T cells as well as dendritic cells (DCs). Two CD4(+) T cell populations with opposing functions present in the intestines and the mesenteric lymph nodes express CCR6: the pro-inflammatory TH17 and regulatory Treg cells. CCL20 is also present in the intestine and is strongly up-regulated after an inflammatory stimulus. Interestingly, this ligand is also expressed by TH17 cells, which opens up the possibility of autocrine/paracrine signaling and, consequently, a self-perpetuating cycle of recruitment, thereby promoting inflammation. Recently, CCR6 has been implicated in inflammatory bowel disease (IBD) by genome wide association studies which showed an association between SNPs in the genomic region of the CCR6 gene and the inflammation. Furthermore, recent research targeting the biological function of CCR6 indicates a significant role for this chemokine receptor in the development of chronic IBD. It is therefore possible that IBD is facilitated by a disordered regulation of TH17 and Treg cells due to a disruption in the CCL20-CCR6 axis and consequently disturbed mucosal homeostasis. This review will summarize the literature on CCL20-CCR6 in mucosal immunology and will analyze the role this receptor-ligand axis has in chronic IBD.
Retention of knowledge and perceived relevance of basic sciences in an integrated case-based learning (CBL) curriculumBACKGROUND: Knowledge and understanding of basic biomedical sciences remain essential to medical practice, particularly when faced with the continual advancement of diagnostic and therapeutic modalities. Evidence suggests, however, that retention tends to atrophy across the span of an average medical course and into the early postgraduate years, as preoccupation with clinical medicine predominates. We postulated that perceived relevance demonstrated through applicability to clinical situations may assist in retention of basic science knowledge. METHODS: To test this hypothesis in our own medical student cohort, we administered a paper-based 50 MCQ assessment to a sample of students from Years 2 through 5. Covariates pertaining to demographics, prior educational experience, and the perceived clinical relevance of each question were also collected. RESULTS: A total of 232 students (Years 2-5, response rate 50%) undertook the assessment task. This sample had comparable demographic and performance characteristics to the whole medical school cohort. In general, discipline-specific and overall scores were better for students in the latter years of the course compared to those in Year 2; male students and domestic students tended to perform better than their respective counterparts in certain disciplines. In the clinical years, perceived clinical relevance was significantly and positively correlated with item performance. CONCLUSIONS: This study suggests that perceived clinical relevance is a contributing factor to the retention of basic science knowledge and behoves curriculum planners to make clinical relevance a more explicit component of applied science teaching throughout the medical course.
The CCR6-CCL20 axis in humoral immunity and T-B cell immunobiologyA review of the role and clinical utility of anti-Ro52/TRIM21 in systemic autoimmunityAdrian Y. S. Lee|Rheumatology International|2017 Brief Report: Identification of a Pathogenic Variant in TREX1 in Early‐Onset Cerebral Systemic Lupus Erythematosus by Whole‐Exome SequencingObjective. Systemic lupus erythematosus (SLE) isa chronic and heterogeneous autoimmune disease. Both twin and sibling studies indicate a strong genetic contribution to lupus, but in the majority of cases the pathogenic variant remains to be identified. The genetic contribution to disease is likely to be greatest in cases with early onset and severe phenotypes. Whole-exome sequencing now offers the possibility of identifying rare alleles responsible for disease in such cases. This study was undertaken to identify genetic causes of SLE using whole-exome sequencing.Methods. We performed whole-exome sequencing in a 4-year-old girl with early-onset SLE and conducted biochemical analysis of the putative defect.Results. Whole-exome sequencing in a 4-year-old girl with cerebral lupus identified a rare, homozygous mutation in the three prime repair exonuclease 1 gene(TREX1) that was predicted to be highly deleterious.The TREX1 R97H mutant protein had a 20-fold reduction in exonuclease activity and was associated with an elevated interferon-alpha signature in the patient.The discovery and characterization of a pathogenic TREX1 variant in our proband has therapeutic implications.The patient is now a candidate for therapy. Conclusion. Our study is the first to demonstrate that whole-exome sequencing can be used to identify rare or novel deleterious variants as genetic causes of SLE and, through a personalized approach, improve therapeutic options.