Influence of a monocyte chemoattractant protein 1 mutated allele on the response to protease inhibitor-based antiretroviral therapy

Background Antiretroviral drug efficacy has been widely studied in relation to viral factors. Mutations in the HIV co-receptors and their natural chemokines, however, may be critical in HIV infection and treatment response. We compared the efficacy of protease inhibitor (PI) treatment among PI-naive patients grouped according to whether they carried the chemokine CC motif receptor 2 (CCR-2) 64I and monocyte chemoattractant protein 1 (MCP-1)-2518G alleles. Methods and results HIV-infected patients who were PI-naive were selected for the study (n=164) but there was no restriction on lymphocyte CD4 count or plasma HIV viral load. Follow-up was for the first 24 months of treatment. Clinical and laboratory data were obtained every 3 months. All the participants were genotyped for the MCP-1-2518G, CCR-2 64I, CCR-5 Delta 32 and stromal derived factor 1 (SDF1) 3'A mutated alleles. The results indicated that patients carrying the mutated allele of MCP-1 had a higher mean CD4 cell count throughout the follow-up period than those with the common allele (P=0.01). Also, patients with the MCP-1 and CCR-2 mutated alleles were more likely to continue to have an undetectable viral load following treatment (P=0.05). Conclusion A better response to PI treatment appears to be conferred by mutations in the host MCP-1 and CCR-2 genes, and may be related to the cellular axis-of-entry used by the retrovirus.