Abstract Background: Alopecia areata is an autoimmune disease that produces non-scarring hair loss around the body. Gene variants of the cytotoxic T-lymphocyte antigen 4 (CTLA4) gene, a negative regulator of T-cell response, have been associated with a predisposition to autoimmune diseases in different populations; however, the involvement of these genetic variants in the development of AA is controversial. Objective: The present study evaluated the potential association of two CTLA4 gene variants with alopecia areata in a Mexican population. Methods: We genotyped +49AG (rs231775) and CT60 (rs3087243) variants in 50 AA patients and 100 healthy control participants through PCR-RFLP. Results: No statistical difference was observed for either of the gene variants regarding allele or genotype frequencies between AA patients and the controls when the parameters of family/personal history of autoimmune diseases or gender were considered (p > 0.05). Study limitations: Small sample size of patients and the data were obtained from Northeast Mexico population. Conclusion: The genetic variants rs231775 and rs3087243 of the CTLA4 gene are not a risk factor for the development of alopecia areata in the analyzed Mexican population.

Abstract: Background: Vitiligo is characterized by a lack of pigmentation in the skin. To date, there are no studies that analyze the changes in gene expression in the skin of vitiligo patients in response to narrow-band ultraviolet B (nb-UVB) phototherapy treatment. Objective: Explore the usefulness of new generation RNA sequencing in the identification of gene expression changes in the skin of vitiligo patients treated with nb-UVB phototherapy. Methods: Four skin biopsies (4mm in diameter) were collected from 45 Mexican vitiligo vulgaris patients, 2 specimens before and 2 after treatment with nb-UVB phototherapy, obtained from pigmented and non-pigmented tissue. RNA extracted from the biopsies was analyzed using the Illumina TruSeq Targeted RNA Expression protocol to study the expression of genes that participate in pathways of skin homeostasis. The 2 groups were compared using Student's t-test and the Mann-Whitney U-test. Results: The expression analysis identified differences in 12 genes included in this study after comparing the samples obtained before and after treatment: 5 genes involved in skin pigmentation, 2 genes involved in apoptosis, 2 genes involved in cell survival, 2 genes involved in oxidative stress responses and 1 gene involved in signal transduction mechanisms (p<0.05). Study limitations: The small size of skin biopsies limits the amount of RNA obtained, the number of genes to be analyzed and the use of conventional techniques such as RT-qPCR. Conclusion: We demonstrated usefulness of new generation RNA sequencing in the identification of gene expression changes, in addition to identifying new targets in the study of vitiligo.