RESUMEN
Onychomycosis is known to have predisposing factors and a high prevalence within families that cannot be explained by within-family transmission. We determined the frequency of HLA-B and HLA-DR haplotypes in 25 families of Mexican patients with onychomycosis in order to define the role of the class II major histocompatibility complex (MHC) in genetic susceptibility to this infection. Seventy-eight subjects participated in the study, 47 with onychomycosis and 31 healthy individuals. The frequencies of the HLA-B and HLA-DR haplotypes were compared with those found in first-degree relatives without onychomycosis and in a historic control group of healthy individuals. The frequencies in the controls were similar to those of the healthy relatives of the patients. However, on comparison of the patients with historic controls, we detected a higher frequency of the HLA-DR8 haplotype (P=.03; odds ratio, 1.89; 95% confidence interval, 0.98-36). These findings suggest that there are polymorphisms in genes of the MHC that increase susceptibility to onychomycosis, particularly haplotype HLA-DR8.
Asunto(s)
Dermatosis del Pie/genética , Genes MHC Clase II , Genes MHC Clase I , Antígenos HLA-B/genética , Antígenos HLA-DR/genética , Dermatosis de la Mano/genética , Onicomicosis/genética , Polimorfismo Genético , Tiña del Cuero Cabelludo/genética , Alelos , Etnicidad/genética , Salud de la Familia , Dermatosis del Pie/epidemiología , Dermatosis del Pie/etnología , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Subtipos Serológicos HLA-DR/genética , Dermatosis de la Mano/epidemiología , Dermatosis de la Mano/etnología , Haplotipos , Humanos , México/epidemiología , Onicomicosis/epidemiología , Onicomicosis/etnología , Tiña del Cuero Cabelludo/epidemiologíaRESUMEN
BACKGROUND: Onychomycosis is multifactorial in origin. Studies have suggested an autosomal dominant pattern of inheritance and human leukocyte antigen DR4 (HLA-DR4) has been shown to protect against onychomycosis in an Ashkenazi Jewish population. AIM: This study investigates HLA class II association in a Mexican Mestizo population with Trichophyton rubrum onychomycosis. METHODS: This was a prospective case-control study. Mexican Mestizos with a clinical diagnosis of onychomycosis and culture positive for T. rubrum were recruited, together with age- and sex-matched controls. First-degree relatives were also investigated for onychomycosis. Case-control samples were HLA typed by polymerase chain reaction sequence-specific primer based analysis. RESULTS: Twenty-one cases and 42 controls were recruited with a mean age of 40 years (range: 18-58 years). HLA-DR6 was found in seven (33%) cases and 19 (45%) controls [P < 0.023, odds ratio (OR) = 0.088, 95% confidence interval (CI): 0.01-0.71]. Six (29%) cases and three (7%) controls had an affected child (P < 0.043, OR = 9.15, 95% CI: 1.07-78.31), and 13 (62%) cases and 12 (29%) controls had an affected first-degree relative (P < 0.02, OR = 4.0, 95% CI: 1.1-14.3). CONCLUSIONS: These results suggest that HLA-DR6 confers protection against the development of onychomycosis in a Mexican Mestizo population. Having an affected first-degree relative significantly increases the risk of onychomycosis, suggesting genetic susceptibility.
Asunto(s)
Predisposición Genética a la Enfermedad , Antígeno HLA-DR6/genética , Onicomicosis/etnología , Onicomicosis/genética , Adolescente , Adulto , Alelos , Población Negra/genética , Estudios de Casos y Controles , Femenino , Genotipo , Humanos , Indígenas Sudamericanos/genética , Masculino , México/epidemiología , Persona de Mediana Edad , Onicomicosis/microbiología , Estudios Prospectivos , Trichophyton/aislamiento & purificación , Población Blanca/genética , Adulto JovenRESUMEN
This study was conducted to evaluate the occurrence of mycoses affecting the feet of soccer players and to compare this results with those in non-athlete individuals of the same age and sex. Initial evaluation consisted of a dermatological examination of the foot in 22 Chinese athletes, 83 Brazilian athletes and 24 Brazilian non-athletes. Scales of plantar skin, interdigital and subungual areas of the foot were collected for mycological examination (direct and culture). Nail clippings were obtained for histopathologic analysis. Tinea pedis was diagnosed more frequently among the non-athlete individuals. None of the Chinese athletes had tinea pedis alone. However, in this group onychomycosis was frequently higher when compared to the other groups. The fungal microbiota comprised Trichophyton rubrum (40%), Trichophyton mentagrophytes (36.4%) and Candida spp (20%). Candida spp was isolated only from Brazilian athletes. Results obtained with KOH wet mounts agreed with the results obtained in culture and with histopathologic examinations (50.5% vs 40.9%). The frequency of tinea pedis among soccer players was lower than the other groups in this study, possibly due to health education and professional feet care.