HIV-Associated Polyneuropathy in Resource-Limited Settings: Genetic Predisposition and Vitamin Variations

Abstract

Human immunodeficiency virus-related polyneuropathy remains a painful condition resulting from damaged nerve endings. HIV infection strongly associates with a predominantly polyneuropathy that is attributed to HIV infection itself, or a toxic neuropathy associated with combination antiretroviral therapy (CART). In non-HIV-infected individuals, both deficiency and high intake of vitamins have been associated with polyneuropathy. For that reason, clinicians recommend vitamin supplements before and during CART. Although some, but not all, HIV-related vitamin deficiencies may replete during treatment with CART, it is predictable that high vitamin supplement intakes may contribute to nerve disorders. In resource-limited settings where the diagnosis of polyneuropathy heavily relies on symptoms, data on risk factors for polyneuropathy including vitamin status, alcohol consumption, and co-infections are limited. In addition, studies on genetic influence on the concentration of micronutrients in the blood of long-term users of CART are scarce. Possible sources of high intakes of vitamins could arise from the fact that a number of HIV-infected persons self-medicate. In addition, since HIV-infected individuals have an increased lifespan, relying on symptoms alone to specifically diagnose HIV-associated neuropathies could be a barrier to effective treatment in recourse-poor settings. This paper reviews evidence on single nucleotide polymorphisms (SNPs) with the potential to influence bioavailability of vitamins in HIV-infected patients. Genome-wide association studies have reported SNPs in alkaline phosphatase, fucosyltransferase 2, cubilin, transcobalamin 1, and tumor necrosis factor as potential determinants of various blood levels of vitamin B-6, B-12 and E. As long term CART increasingly become, personalized, future research should focus on SNPs, which influence vitamin blood levels, and with potential to augment long-term treatment with CART.