P032 Human leucocyte antigen class II typing of lepromatous leprosy in the Philippines: a clinicopathological correlation of two cases

Abstract Leprosy, caused by Mycobacterium leprae, is a prevalent disease in Southeast Asia and in the Philippines. The disease manifests in various forms, with the lepromatous type prevalent among new cases. While only a small percentage of those infected develop symptoms, genetic predisposition, particularly involving the human leucocyte antigens (HLAs), may influence disease activity. Previous studies have identified specific HLA alleles associated with leprosy, but there is a lack of research on HLA associations with lepromatous leprosy in the Philippines. Two Filipino patients with lepromatous leprosy and one of their disease-free siblings were studied. Patient A, a 21-year-old man, exhibited skin lesions and sensory loss. After 1 year of multidrug therapy, he showed improvement with residual hyperpigmentation. Patient B, a 25-year-old man, experienced a lepra reaction during treatment, persistent lesions, and new nodules despite extended therapy. Both patients and their asymptomatic siblings were tested for HLA class II typing, which revealed the presence of HLA-DRB1*15 in patient B and his sibling. This study highlights the genetic aspects of susceptibility to leprosy, focusing on HLA class II alleles. The presence of HLA-DRB1*15 has been described as a susceptibility marker in lepromatous leprosy in several studies. Its presence may herald a longer treatment duration and occurrence of reversal reactions. However, the presence of certain genotypes in a patient with leprosy warrants further investigation. Larger studies are needed to better understand the genetic factors influencing leprosy susceptibility in the Philippines.