Incidence of adverse cutaneous drug reactions in a Mexican sample: an exploratory study on their association to tumour necrosis factor alpha TNF2 allele.

ABSTRACT

BACKGROUND: Most adverse cutaneous drug reactions (ACDR) are mediated by delayed hypersensitivity (dh) with lymphocyte recruitment and inflammatory cytokines release, including tumour necrosis factor alpha (TNFalpha). Polymorphisms in the TNFalpha gene, such as the infrequent allele TNF2, predispose to certain inflammatory entities and enhance TNFalpha production. The incidence of the TNF2 allele is increased in British patients with severe ACDR, suggesting TNFalpha as a major contributor in the pathogenesis of ACDR. OBJECTIVE: We designed a prospective study to analyse the epidemiology of ACDR in a third-level Mexican hospital and explore the possibility of a relationship between the TNF2 allele and ACDR-dh. METHODS: A prospective study during 9 months allowed recognition of 34 ACDR-dh patients. The study included 33 paired patients, and 44 healthy volunteers. All subjects were genotyped for TNF2 by PCR DNA amplification and NcoI restriction endonuclease digestion. Results Incidence of ACDR was 0.95%. The TNF2 allele was detected in 9.9% of the sample population with no significant differences between healthy controls, and patients with or without ACDR-dh. Only 3 of the 34 ACDR-dh subjects presented severe reactions, with 1 having the TNF2 allele. Comorbidity analysis showed significance only with autoimmune thyroid disease, consistent with reports on Chinese and Tunisian patients. CONCLUSION: ACDR incidence and TNF2/TNFA heterozygosity were lower in Mexican than in Caucasian patients. ACDR-dh patients showed no increased frequency in the TNF2 allele.