Association between the cytotoxic T-lymphocyte antigen-4 mutations and the susceptibility to systemic lupus erythematosus; Contribution markers of inflammation and oxidative stress

The cytotoxic T lymphocyte antigen-4 (CTLA-4) also known as CD152 (cluster of differentiation 152) is a crucial negative regulator of the immune system. This protein receptor provides negative signals in order to suppress T-cell activation and immune attack against self-antigens, although its role is unclear.  The ability of CTLA-4 to limit T cell-mediated immune response has made it a major target in treatment of tumors and autoimmune diseases such as systemic lupus erythematosus (SLE). In this study, we investigated whether CTLA-4 G-1661A and CTLA-4 T-1722C mutations are associated with SLE. So one hundred nine SLE patients and 101 gender and age-matched unrelated healthy controls were recruited for this case-control study. The promoter mutations were detected by PCR-RFLP, neopterin, malondialdehyde (MDA) and serum lipid concentration were determined by HPLC and enzyme assay, respectively.

RESULT

We found that both codominant (AA vs. GG) and recessive (AA vs. GA+GG) CTLA-4 G-1661A mutation significantly decreased the risk of SLE by 1.7 and 3.7 times, respectively.  Interestingly, SLE patients with AA genotypes of CTLA-4 G-1661A have lower neopterin and MDA concentration compared with GA+GG genotypes. The overall distribution of CTLA-4 T-1722C genotypes and alleles in SLE patients were similar to those in control group. In conclusion, our findings showed, that there is an association between systemic inflammatory markers, oxidative stress and the CTLA-4 G-1661A GG+AG genotypes, MDA and neopterin which are the most conventional risk factors for coronary heart disease, therefore these mutations may be consider as a risk factor for susceptibility to heart disease in SLE patients.

Pharmacogenetics of drug metabolizing enzyme: thiopurine methyl transferase phenotypes and multidrug resistance 1 gene polymorphism in inflammatory bowel disease

Inflammatory bowel disease(IBD) is progressing rapidly in developing countries such as Iran. This research is intended to compile the frequency distribution of the drug metabolizing enzyme, thiopurine methyl transferase(TPMT) and the drug transporter, Multi drug resistance(MDR1) which are involved in metabolism of many therapeutics such as thiopurines in inflammatory bowel disease(IBD). Ethnicity is an important variable influencing drug response. The aims of this research were to investigate the association of TPMT phenotypes with MDR1 genotypes. TPMT activity was measured by using a non-extraction HPLC method and genotype for the C3435T polymorphism of MDR1 gene was determined in 215 unrelated IBD patients including of 85 males and 130 females and 212 unrelated healthy individuals consisted of 96 males and 116 females as control group by PCR-RFLP in Iran's western population. TPMT phenotypes demonstrated no frequency for deficient, 2.2% for low and 97.8% for normal activity that is different with results of other studies. Interestingly there were a significant negative correlation between TPMT activities as calculated based on nmol/grHb/h and positive correlation calculated in mU/L with Hb levels in IBD patients and control subjects. Dominant and codominant MDR1 C3435T gene polymorphism increased the risk of IBD by 1.45 and 1.46 times, respectively. IBD patients with MDR1 mutant genotypes C3435T, had lower TPMT activites and Hb concentrations. Using of mU/L is more appropriate than nmol6MTG/grHb/h for expressing TPMT activity. TPMT frequency of deficient and low activity in western Iran is low. The carriers of mutant C3435T MDR1 are not good TPMT methylators.