Belén Torres

CTLA4 polymorphism in Spanish patients with systemic lupus erythematosus.

The cytotoxic T-lymphocyte antigen 4 (CTLA4, CD152) gene is a positional and functional candidate gene to susceptibility to systemic lupus erythematosus (SLE) because CTLA4 gene maps in the described SLE risk region 2q33 and CTLA4 molecule has an inhibitory effect on T-cell activation. Several polymorphisms have been described in CTLA4 gene, among them, a T/C change at position -1722, a C/T transition at position -319, and another A/G transition at position +49. The aim of this study was to investigate the possible association of these polymorphisms with the susceptibility to SLE in 276 Spanish autochthonous patients using a healthy control group composed of 194 ethnically matched volunteer bone marrow donors. Genotyping of these CTLA4 positions was performed in SLE patients and controls using a polymerase chain reaction amplification refractory mutation system. The genotypic frequencies were in Hardy-Weinberg equilibrium in all patients. No differences in the distribution of the genotype frequencies between patients and controls were found in any case. Our results from the Spanish autochthonous population differ from those found in the Korean population regarding the involvement of the polymorphism located at -1722 in the susceptibility to SLE.

MCP-1 promoter polymorphism in spanish patients with rheumatoid arthritis

To investigate the possible role of the polymorphism located in the regulatory region of monocyte chemoattractant protein-1 (MCP-1) gene in the susceptibility to rheumatoid arthritis (RA), a total of 141 Spanish RA patients and 194 controls, previously typed for human leukocyte antigen DRB1* (HLA-DRB1*), were genotyped for -2518 (A/G) MCP-1 gene polymorphism using polymerase chain reaction-restriction fragment length polymorphism. No association between -2518 (A/G) MCP-1 polymorphism and susceptibility to RA was found. Nevertheless, when patients and controls were stratified according to their HLA shared epitope (SE) status, a significant increase in the frequency of genotype GG was found among SE negative (SE-) patients with respect to both SE positive (SE+) patients and SE- controls (16% versus 4% in SE+ patients, pFisher=0.04, odds ratio [OR]=4.4, 95% confidence interval [95%CI]=1.03-21.48; and 4% in SE- controls, pFisher=0.02, OR=4.13, 95%CI=1.10-15.72). In conclusion, MCP-1 polymorphism is slightly associated with the susceptibility to RA in patients lacking the HLA SE.

HLA class I B44 is associated with sustained response to interferon + ribavirin therapy in patients with chronic hepatitis C

OBJECTIVE:The aim of this study was to assess the influence of host genetic factors on response to combination therapy for chronic hepatitis C infection.METHODS:Patients with biopsy-proved chronic hepatitis C infection were treated with interferon alone (n = 143) or combined therapy of interferon + ribavarin (n = 105; 46 treatment naïve, 59 relapsers). Human leukocyte antigen (HLA) class I was determined by microlymphocytotoxicity and class II by polymerase chain reaction-single specific oligonucleotide. The two biallelic tumor necrosis factor-α promoter polymorphisms were studied by a polymerase chain reaction-amplification refractory mutation system. Other variables measured were viral genotype, hepatitis C virus RNA load, liver function tests, and ferritin concentration.RESULTS:Univariate analysis indicated that patients bearing HLA B44+, DRB1*03, infected by genotype non-1, with higher concentrations of transaminases and shorter duration of infection showed a higher sustained response (SR) rate than those on combination therapy. HLA class II and TNF-α promoter polymorphisms were not related to SR. In multivariate analysis, non-1 genotype (OR 2.42, 95% CI 1.12–5.55, p = 0.026) and HLA B44+ (OR 4.84, 95% CI 1.3–17.8, p = 0.017) were the independent variables associated with SR. However, HLA B44+ was not associated with SR in patients treated with interferon alone.CONCLUSIONS:HLA class I B44 is related to a higher rate of SR in combination therapy but not in interferon monotherapy, whereas HLA class II, tumor necrosis factor-α −238A or −308A seem not to influence response to the antiviral therapy. These findings may be of value in therapy selection for hepatitis C-infected patients.

SLC11A1 promoter gene polymorphisms and fibrosis progression in chronic hepatitis C

Background and aims: The solute carrier family 11 member 1 (SLC11A1) gene (formerly Nramp1) encodes for the protein solute carrier family 11, member 1. It affects susceptibility and clinical outcome of autoimmune and infectious diseases. We investigated the possible role of the functional polymorphism located in the promoter region of SLC11A1 and tumour necrosis factor (TNF) genes in the progression of fibrosis in chronic hepatitis C. Methods: A total of 242 Caucasian Spanish patients with biopsy proven chronic hepatitis C and 194 healthy control subjects were genotyped for SLC11A1 and TNF promoter polymorphisms. Results: No significant differences in the distribution of frequencies among patient and control groups were observed. The SCL11A1 homozygous 2/2 genotype was rarely detected among patients showing advanced fibrosis (2/82; 2.4%) but was highly represented in those with mild fibrosis (29/160; 18.1%; odds ratio (OR) 8.85 (95% confidence interval (CI) 1.9–55.2, pc = 0.002). In patients carrying allele 3 of SLC11A1, the presence of −238 TNF A/G was associated with advanced fibrosis (14/26 (53.8%) v 68/216 (31.4%); OR 2.53 (95% CI 1.03–6.23); p = 0.02). Conclusions: SLC11A1 gene promoter polymorphism could influence fibrosis progression in chronic hepatitis C in that the homozygous genotype 2/2 exerts a protective effect against cirrhosis development. Also, the combination of TNF −238 A/G and the presence of allele 3 is conducive to progression to pre-cirrhotic or cirrhotic stages of the disease.

The AIRE gene and susceptibility to rheumatoid arthritis in the Spanish population

AIRE is a transcriptional regulator that plays a functional role in thymocyte education and negative selection by controlling the expression of peripheral antigens in thymus. This gene has been associated with the susceptibility to rheumatoid arthritis (RA) in a recent GWAS carried out in the Japanese population; nevertheless, no association has been described in Caucasian populations.