HIV-1 p24 and CD4+T cell count during boosted protease-inhibitor monotherapy in HIV-infected patients

Background: Plasma HIV p24 is considered a significant predictor of CD4(+) T cell decline and progression to AIDS in HIV-infected patients. We evaluated the p24 levels in patients on triple therapy and after switching to ritonavir-boosted protease inhibitor monotherapy (mtPI/rtv), as well as the relationships with virological and immunological evolution. Materials and methods: Plasma samples from patients participating in two studies of simplification to mtPl/rtv were analysed for presence of p24, using a boosted enzyme -linked immunosorbent assay specific for mature p24. Only patients with available samples at baseline (on triple therapy) and during a follow-up of at least 12 months after switching to mtPI/rtv were included. Results: A total of 233 samples from 51 patients were analysed. After switching to mtPI/rtv and a median follow-up of 24 months, 14 patients maintained continuous undetectable viraemia, and 37 patients experienced a total of 49 transient viraemic episodes. Unexpectedly, the evolutionary p24 patterns were uniform for most patients, both before and after switching to mtPl/rtv, independently of the virological behaviour, fitting into one of three categories: persistent undetectable p24 levels, positive p24, matching only with the viraemic episodes, and persistent detectable p24 levels. The last group showed lower CD4(+) T cell counts and percentages, as well as lower CD4(+)CD8(+) T cell ratios after 12 and 24 months of follow up. Conclusion: Treatment simplification to mtPl/rtv does not influence the behaviour of p24 in plasma. Patients with continuous positive p24, despite undetectable viraemia, showed worse immunological evolution.(C) 2016 Elsevier Espafia, S.L.U. and Sociedad Espailola de Enfermedades Infecciosas y Microbiologia Clinica. All rights reserved.