Cell mediated immunity is currently thought to be involved in the pathogenesis of oral mucosal lichen planus (OMLP). However, literature reveals there is no large scale data of immunohistochemistry (IHC) study on these immune cell populations. The aim of this study was to assess and compare immune cell surface identification markers CD3, CD4, CD8, CD19 and CD83 between the OMLP (n=40) and non-specific inflammatory lesions (as control group) (n=10) qualitatively and quantitatively. Kruskal-Wallis and Mann Whitney U tests have been used to make comparison between the test and control group, p values of less than 0.05 was considered to be statistically significant. T cell surface markers (CD3+, CD4+ and CD8+), B cells (CD19+) and mature dendritic cells (CD83+) showed intense immunostaining in OMLP tissues with a significantly higher expression of positive cells than in the control group (p<0.05). CD3, CD4 and CD8+ve T cells were the predominant inflammatory cell type in OMLP rather than CD19+ B cells, supporting the role of Th1 cells in the pathogenesis of OMLP. CD83+ mature dendritic cells were present in the least number and were mostly localized to areas where there were aggregates of lymphocyte. There was a positive correlation and direct relationship between T and B lymphocyte subsets whereby as one subset increased, the other follows.
Molecular dissection of inborn errors of immunity can help to elucidate the nonredundant functions of individual genes. We studied 3 children with an immune dysregulation syndrome of susceptibility to infection, lymphadenopathy, hepatosplenomegaly, developmental delay, autoimmunity, and lymphoma of B-cell (n = 2) or T-cell (n = 1) origin. All 3 showed early autologous T-cell reconstitution following allogeneic hematopoietic stem cell transplantation. By whole-exome sequencing, we identified rare homozygous germline missense or nonsense variants in a known epigenetic regulator of gene expression: ten-eleven translocation methylcytosine dioxygenase 2 (TET2). Mutated TET2 protein was absent or enzymatically defective for 5-hydroxymethylating activity, resulting in whole-blood DNA hypermethylation. Circulating T cells showed an abnormal immunophenotype including expanded double-negative, but depleted follicular helper, T-cell compartments and impaired Fas-dependent apoptosis in 2 of 3 patients. Moreover, TET2-deficient B cells showed defective class-switch recombination. The hematopoietic potential of patient-derived induced pluripotent stem cells was skewed toward the myeloid lineage. These are the first reported cases of autosomal-recessive germline TET2 deficiency in humans, causing clinically significant immunodeficiency and an autoimmune lymphoproliferative syndrome with marked predisposition to lymphoma. This disease phenotype demonstrates the broad role of TET2 within the human immune system.