UVB suscetibilidade como fator de risco para o desenvolvimento da hanseníase virchowiana / UVB susceptibility as a risk factor to the development of lepromatous leprosy

FUNDAMENTOS: A radiação ultravioleta B (RUVB) é o mais importante fator ambiental capaz de modificar a função imunológica da pele humana. OBJETIVO: estudar a associação entre o fenótipo de suscetibilidade ou resistência à radiação RUVB e as formas polares da hanseníase. MATERIAL E MÉTODOS: foram avaliados 38 pacientes com hanseníase virchowiana (MHV) e 87 pacientes com hanseníase tuberculoide (MHT) de acordo com a classificação de Ridley e Jopling (1966). Todos os pacientes foram submetidos ao teste para determinação do fenótipo de suscetibilidade ou resistência à RUVB por meio da aplicação de um disco de dinitroclorobenzeno (DNCB) a 2 por cento em uma área de pele previamente irradiada com duas vezes a dose eritematosa mínima (DEM). Após 21 dias, outra aplicação de um disco similar de DNCB a 0,05 por cento na região escapular (área não exposta à RUVB) foi realizada para avaliar se houve sensibilização, com leitura após 48 horas. Os pacientes que apresentaram reação positiva ao DNCB foram considerados UVB-resistentes e o oposto foi considerado para aqueles que não apresentaram resposta (UVB-suscetíveis). RESULTADOS: A frequência de UVB-suscetíveis foi de 63,2 por cento (24 pacientes) no grupo MHV e 34,4 por cento (30 pacientes) no grupo MHT (OR = 3,26; IC = 1,36-7,87; x² = 7,73; p = 0,005). CONCLUSÃO: Os resultados sugerem que a UVB-suscetibilidade é um fator de risco para o desenvolvimento da MHV.

BACKGROUNDS: Ultraviolet radiation B (UVRB) is the most important environmental factor capable of altering the immune function of human skin. OBJECTIVE: To evaluate the association of the phenotypes of susceptibility or resistance to ultraviolet radiation B (UVRB) and the polar forms of leprosy. MATERIAL AND METHODS: 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 percent 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 percent 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). RESULTS: The frequency of UVB-S individuals was 63.2 percent (24 patients) in the LL group and 34.4 percent (30 patients) in the TT group (OR=3.26; IC=1.36 - 7.87; x²=7.73; p=0.005). CONCLUSION: Our results suggest that UVB-susceptibility is a risk factor to the development of lepromatous leprosy (LL).

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

BACKGROUNDS: Ultraviolet radiation B (UVRB) is the most important environmental factor capable of altering the immune function of human skin. OBJECTIVE: To evaluate the association of the phenotypes of susceptibility or resistance to ultraviolet radiation B (UVRB) and the polar forms of leprosy. MATERIAL AND METHODS: 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). RESULTS: 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). CONCLUSION: Our results suggest that UVB-susceptibility is a risk factor to the development of lepromatous leprosy (LL).