1. ¹Leprosy Laboratory, Department of Mycobacterioses, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil
2. ²Department of Epidemiology and Quantitative Methods in Health (DEMQS), Escola Nacional de Saúde Pública (ENSP), FIOCRUZ, Rio de Janeiro, Brazil
3. ³Immunogenetics Laboratory, Instituto Nacional do Câncer, Ministério da Saúde, Rio de Janeiro, Brazil
4. ⁴INSERM U.550, Necker Medical School, Paris, France
5. ⁵Departments of Human Genetics, Medicine and Biochemistry, McGill Centre for the Study of Host Resistance, McGill University, Montreal, Canada
6. ⁶Hospital for Dermato-Venereology, Ho Chi Minh City, Vietnam

Correspondence: Dr MO Moraes, Leprosy Laboratory, Department of Tropical Medicine, Oswaldo Cruz Institute, FIOCRUZ, Av. Brasil, 4365, Manguinhos, Rio de Janeiro, RJ 21045-900, Brazil. E-mail: mmoraes@fiocruz.br

Received 27 October 2006; Revised 2 January 2007; Accepted 14 February 2007; Published online 29 March 2007.

Abstract

The host genetic background has been considered one of the factors that influence leprosy outcome, a chronic infectious disease caused by Mycobacterium leprae. Genome scans demonstrated that the 6p21 region is associated with leprosy and a substantial number of population-based studies analyzing human leukocyte antigen (HLA) class II loci suggested association of HLA-DR with leprosy. However, some studies lacked robustness as they had limited power. Indeed, experimental designs require increased sample size to achieve adequate power, as well as replication studies with independent samples for confirmation of previous findings. In this work, we analyzed the influence of the HLA-DRB1 locus on leprosy susceptibility per se and disease type using a case–control design carried out in Brazilians (578 cases and 691 controls) and a replication study based on a family design in a Vietnamese population (n=194 families). The results showed that HLA-DRB1^*10 is associated with susceptibility to leprosy and HLA-DRB1^*04 is associated with resistance, both in the Brazilian and Vietnamese populations suggesting that these alleles play an important role in the activation of cellular immune responses against M. leprae.