UVB susceptibility as a risk factor to the development of lepromatous leprosy

• Published in: Anais brasileiros de dermatología 2010-11, Vol.85 (6), p.839-842
• Main Authors: Rodrigues, Mecciene Mendes, Ximenes, Ricardo Arraes de Alencar, Dantas, Mecleine Mendes da S, Batista, Thaísa Delmondes, Freire, Alzírton de Lira
• Format: Article
• Language: eng ; por
• Subjects: Adolescent; Adult; Dinitrochlorobenzene; Disease Susceptibility; Female; Humans; Indicators and Reagents; Leprosy, Lepromatous - etiology; Leprosy, Tuberculoid - etiology; Male; Middle Aged; Phenotype; Radiation Tolerance - physiology; Risk Factors; Ultraviolet Rays - adverse effects; Young Adult
• ISSN: 1806-4841
• DOI: 10.1590/S0365-05962010000600009

Ultraviolet radiation B (UVRB) is the most important environmental factor capable of altering the immune function of human skin. To evaluate the association of the phenotypes of susceptibility or resistance to ultraviolet radiation B (UVRB) and the polar forms of leprosy. We evaluated 38 patients with lepromatous leprosy (LL) and 87 patients with tuberculoid (TT) leprosy, according to the classification by Ridley and Jopling (1966). All the patients were submitted to a test to determine the phenotypes of susceptibility or resistance to UVRB through the application of a 2% dinitrochlorobenzene (DNCB) disc to a previously irradiated area with twice the minimal erythema dose (MED). After 21 days, a similar disc soaked in 0.05% DNCB was applied to the scapular area (unexposed to UVRB) to check for sensitiveness, with reading of the results after 48 hours. The patients that showed a positive reaction to DNCB were considered resistant (UVB-R) and those who did not show any reaction were considered susceptible (UVB-S). The frequency of UVB-S individuals was 63.2% (24 patients) in the LL group and 34.4% (30 patients) in the TT group (OR=3.26; IC=1.36 - 7.87; x(2)=7.73; p=0.005). Our results suggest that UVB-susceptibility is a risk factor to the development of lepromatous leprosy (LL).