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Objective: To examine the contribution of tumor necrosis factor alpha (TNF) microsatellite (a to e) polymorphism to the genetic risk of developing rheumatoid arthritis (RA) in a northwestern Colombian population. Methods: This was an association study in which 108 RA patients and 222 matched individuals were enrolled. HLA-DRB1 and DQB1 polymorphisms were evaluated to examine for linkage disequilibrium between these loci and TNF microsatellites. Genotyping was performed using denaturing polyacrylamide gels and polymerase chain reaction-sequence techniques. Results: By unconditional logistic regression analysis, the TNFa6 allele (OR= 2.37, 95%CI 1.07-5.24) and the TNFb4 allele (OR= 3.01, 95%CI 1.07-9.00) were observed to be associated with disease. These associations were independent of HLA-DR and HLA-DQ since linkage disequilibrium between HLA class II and TNF microsatellites was not observed. In addition, patients with the TNFa8 allele had a five times greater risk of developing extra-articular manifestations as compared to patients without this allele (OR = 5.07, 95%CI 1.14-22.52), regardless of age and the duration of disease. Haplotype analysis disclosed a protective effect for TNFa7/b7/c1/d4/e3/-308G/-238G. Conclusion: These results confirm that the TNF locus exerts a primary influence on both susceptibility to and the severity of RA. © Copyright Clinical and Experimental Rheumatology 2007.

Objective. Considering the significant morbidity and mortality of pulmonary arterial hypertension (PAH) in patients with systemic sclerosis (SSc) and the lack of precise information on disease in Latin America, we investigated the clinical and laboratory characteristics associated with PAH in Colombian patients with SSc and review the literature. Methods. This multicenter study included patients followed at 5 rheumatology units that were systematically assessed using a pretested questionnaire on clinical and immunological variables, focusing on PAH. Conditional logistic regression was employed to assess association between PAH and specific clinical characteristics. A systematic review of the literature was performed through electronic databases. Results. Of a total of 349 patients with SSc, 61 (17%) met the criteria for PAH. Pulmonary fibrosis [adjusted odds ratio (AOR) 7.37, 95% CI 3.67-14.81, p less than 0.0001], microstomia (AOR 3.3, 95% CI 1.70-6.28, p less than 0.0001), gastroesophageal reflux (AOR 2.41, 95% CI 1.31-4.43, p = 0.005), dysphagia (AOR 2.7, 95% CI 1.49-4.77, p = 0.001), hyperpigmentation (AOR 2.15, 95% CI 1.11-4.16, p = 0.02), and hypopigmentation (AOR 2.4, 95% CI 1.26-4.64, p = 0.008) were the most prevalent clinical characteristics associated with PAH, while anemia (AOR 5.4, 95% CI 1.98-14.93, p = 0.001) was observed as the unique laboratory risk factor. Association between subtypes of SSc and PAH was not observed. Significant differences in both clinical and laboratory data were observed among different series. Conclusion. PAH may be a frequent complication of SSc in the Colombian population regardless of disease subtype. The identified clinical and laboratory risk factors might assist earlier diagnosis and guide decisions on therapeutic interventions on this critical complication of SSc. The reasons underlying the reported divergences among patients from different ethnicities are not fully understood, but it is most likely that both genetic and environmental factors are responsible for them.

Tumor necrosis factor alpha antagonists (TNFA) are biological agents to treat chronic inflammatory and autoimmune diseases. However, their use is associated with an increased rate of tuberculosis, endemic mycoses, and intracellular bacterial infections. Since tuberculosis is moderately to highly endemic in Colombia, the risk of these infections in patients treated with TNFAs may be higher than previously reported in Colombia. Recently, four patients have developed tuberculosis during TNFA therapy. Tuberculosis appeared between 3 to 24 months after initiation of TFNA therapy and was independent of previous tuberculin skin test status. A review of the relevant literature and recommendations are presented as guides for surveillance and prophylaxis on a country-wide basis.