CIITA is not associated with risk of developing rheumatoid arthritis

CIITA gene polymorphism (rs3087456) in systemic lupus erythematosus and rheumatoid arthritis: A population-based cohort study

Systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) are influenced by genetic variants in immune system HLA genes. The Class II Major Histocompatibility Complex Transactivator (CIITA) is an important co-activator of the HLA transcriptional complex; the single nucleotide variant (SNV) rs3087456 localized in the gene promoter region (-168 A/G) has been reported as able to modify its transcription level. In our study, we assessed CIITA rs3087456 SNV in 1,044 Brazilians from two Brazilian regions (Northeast and South) to verify the association with susceptibility and clinical manifestations of (SLE) and (RA) using TaqMan SNP Genotyping Assays System. We observed a protection for a recessive model (GG x AA+AG) for RA susceptibility and increased risk for erosion development in AG genotype patients. No significant association was observed for SLE susceptibility; however, we observed significant increased risk for Class IV and V nephritis development in G allele and GG genotype patients. In conclusion, we showed the contribution of CIITA rs3087456 to SLE or RA clinical features and RA susceptibility in the studied populations.

HLA-DRB1 genes and the expression dynamics of HLA CIITA determine the susceptibility to T2DM

Type 2 diabetes mellitus (T2DM) is a disease with polygenic inheritance. The expression of major histocompatibility complex class II genes are regulated by several trans-activators. We have studied the expression of HLA-DRB1, RFX, CIITA-P1, PIV transactivators, immunophenotyping of cells, SNPs in CIITA-168 (A/G) and IFN-γ + 874 (T/A) in T2DM patients and controls (n = 201 each). We observed increased frequencies of DRB1*03, DRB1*04 and DRB1*07 and decreased frequencies of DRB1*10, DRB1*14, and DRB1*15 alleles among patients. Significant up-regulations of HLA-DRB1 genes were observed in patients (p < 0.0001). Down-regulated expressions were documented in DRB1*03-homo (p < 0.002) and DRB1*04-homo (p < 0.009) patients. No significant differences were observed for CIITA-P1 expression except DRB1*04-pooled (p < 0.0113). The CIITA-PIV was up-regulated in overall (p < 0.0001), DRB1*03-pooled (p < 0.0006), DRB1*03-hetero (p < 0.0006) and DRB1*03-homo (p < 0.001) T2DM patients. However, significant down-regulations were documented for DRB1*04-pooled (p < 0.040), DRB1*04-hetero (p < 0.060), and DRB1*04-homo (p < 0.027) combinations. Further, significant down-regulations of RFX5 were observed in overall (p < 0.0006), DRB1*04-pooled (p < 0.0022), and DRB1*04-hetero (p < 0.0004) combinations. Immunophenotyping studies revealed significant increase of CD45⁺ CD14^-, CD19⁺, CD14^- and CD8 cells and elevated level of expression of IFN-γ (p < 0.0001) in patients. A significant increase of TT (p < 3.35 × 10^-6) and decrease of TA (p < 4.57 × 10^-4) genotypes of IFN-γ + 874 (T/A) and an increase of GG (p < 0.001) and decrease of AG (p < 8.24 × 10^-5) genotypes of CIITA-168 A/G SNPs were observed. The combinatorial analysis revealed susceptible associations for DRB1*03 + AA, *03 + AG, *03 + GG and *04 + GG and protective associations for DRB1*10 + AG, *10 + GG, *15 + AG, and *14 + GG combinations. Thus, the present study corroborated the effect of differential expressions of promoters of risk alleles in the pathogenesis of T2DM.

MHC2TA and FCRL3 genes are not associated with rheumatoid arthritis in Mexican patients

Rheumatoid arthritis (RA) is a multifactorial disease. A combination of genetic and environmental risk factors contributes to its etiology. Several genes have been reported to be associated with susceptibility to the development of RA. The MHC2TA and FCRL3 genes have been associated previously with RA in Swedish and Japanese populations, respectively. In two recent reports, we show an association between FCRL3 and juvenile rheumatoid arthritis (JRA), and MHC2TA and acute coronary syndrome (ACS) in Mexican population. We assessed the association between three single nucleotide polymorphisms (SNPs) of the MHC2TA (-168G/A; rs3087456, and +16G/C; rs4774) and FCRL3 (-169T/C; rs7528684) genes and rheumatoid arthritis in Mexican population through a genotyping method using allelic discrimination assays with TaqMan probes. Our case-control study included 249 patients with RA and 314 controls. We found no evidence of an association between the MHC2TA -168G/A and +1614G/C or FCRL3 -169T/C polymorphisms and RA in this Mexican population. In this cohort of Mexican patients with RA, we observed no association between the MHC2TA or FCRL3 genes and this autoimmune disease.

Functions of NOD-Like Receptors in Human Diseases

Nucleotide-binding and oligomerization domain NOD-like receptors (NLRs) are highly conserved cytosolic pattern recognition receptors that perform critical functions in surveying the intracellular environment for the presence of infection, noxious substances, and metabolic perturbations. Sensing of these danger signals by NLRs leads to their oligomerization into large macromolecular scaffolds and the rapid deployment of effector signaling cascades to restore homeostasis. While some NLRs operate by recruiting and activating inflammatory caspases into inflammasomes, others trigger inflammation via alternative routes including the nuclear factor-κB, mitogen-activated protein kinase, and regulatory factor pathways. The critical role of NLRs in development and physiology is demonstrated by their clear implications in human diseases. Mutations in the genes encoding NLRP3 or NLRP12 lead to hereditary periodic fever syndromes, while mutations in CARD15 that encodes NOD2 are linked to Crohn’s disease or Blau’s syndrome. Genome-wide association studies (GWASs) have identified a number of risk alleles encompassing NLR genes in a host of diseases including allergic rhinitis, multiple sclerosis, inflammatory bowel disease, asthma, multi-bacillary leprosy, vitiligo, early-onset menopause, and bone density loss in elderly women. Animal models have allowed the characterization of underlying effector mechanisms in a number of cases. In this review, we highlight the functions of NLRs in health and disease and discuss how the characterization of their molecular mechanisms provides new insights into therapeutic strategies for the management of inflammatory pathologies.

Interaction analysis between HLA-DRB1 shared epitope alleles and MHC class II transactivator CIITA gene with regard to risk of rheumatoid arthritis

HLA-DRB1 shared epitope (SE) alleles are the strongest genetic determinants for autoantibody positive rheumatoid arthritis (RA). One of the key regulators in expression of HLA class II receptors is MHC class II transactivator (CIITA). A variant of the CIITA gene has been found to associate with inflammatory diseases.

We wanted to explore whether the risk variant rs3087456 in the CIITA gene interacts with the HLA-DRB1 SE alleles regarding the risk of developing RA. We tested this hypothesis in a case-control study with 11767 individuals from four European Caucasian populations (6649 RA cases and 5118 controls).

We found no significant additive interaction for risk alleles among Swedish Caucasians with RA (n = 3869, attributable proportion due to interaction (AP) = 0.2, 95%CI: −0.2–0.5) or when stratifying for anti-citrullinated protein antibodies (ACPA) presence (ACPA positive disease: n = 2945, AP = 0.3, 95%CI: −0.05–0.6, ACPA negative: n = 2268, AP = −0.2, 95%CI: −1.0–0.6). We further found no significant interaction between the main subgroups of SE alleles (DRB1*01, DRB1*04 or DRB1*10) and CIITA. Similar analysis of three independent RA cohorts from British, Dutch and Norwegian populations also indicated an absence of significant interaction between genetic variants in CIITA and SE alleles with regard to RA risk.

Our data suggest that risk from the CIITA locus is independent of the major risk for RA from HLA-DRB1 SE alleles, given that no significant interaction between rs3087456 and SE alleles was observed. Since a biological link between products of these genes is evident, the genetic contribution from CIITA and class II antigens in the autoimmune process may involve additional unidentified factors.

The rs4774 CIITA missense variant is associated with risk of systemic lupus erythematosus

The major histocompatibility complex (MHC) class II transactivator gene (CIITA) encodes an important transcription factor required for human leukocyte antigens (HLA) class II MHC-restricted antigen presentation. MHC genes, including the HLA class II DRB1*03:01 allele, are strongly associated with systemic lupus erythematosus (SLE). Recently the rs4774 CIITA missense variant (+1632G/C) was reported to be associated with susceptibility to multiple sclerosis. In the current study, we investigated CIITA, DRB1*03:01 and risk of SLE using a multi-stage analysis. In stage 1, 9 CIITA variants were tested in 658 cases and 1363 controls (N=2021). In stage 2, rs4774 was tested in 684 cases and 2938 controls (N=3622). We also performed a meta-analysis of the pooled 1342 cases and 4301 controls (N=5643). In stage 1, rs4774(*)C was associated with SLE (odds ratio (OR)=1.24, 95% confidence interval (95% CI)=1.07-1.44, P=4.2 × 10(-3)). Similar results were observed in stage 2 (OR=1.16, 95% CI=1.02-1.33, P=8.5 × 10(-3)) and the meta-analysis of the combined data set (OR=1.20, 95% CI=1.09-1.33, P(meta)=2.5 × 10(-4)). In all three analyses, the strongest evidence for association between rs4774(*)C and SLE was present in individuals who carried at least one copy of DRB1*03:01 (P(meta)=1.9 × 10(-3)). Results support a role for CIITA in SLE, which appears to be stronger in the presence of DRB1*03:01.