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HLA-DR6 association confers increased resistance to T. rubrum onychomycosis in Mexican Mestizos


Daniel Asz Sigall, md
Hospital General, “Dr. Manuel Gea González”
Departamento de Dermatología. Calzada de Tlalpan 4800
Tlalpan. CP 14000
Mexico DF, Mexico


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.