 Adult HIV-infected study participants with undetectable 40 copiesmL viral load receiving a standard backbone of two NRTIs either tenofovir TDFemtricitabine FTC or abacavir ABClamivudine 3TC with either a NNRTI efavirenz EFV or rilpivirine RPV or a boosted PI Darunavir DRVr, atazanavir ATZr or Lopinavir LPVr. After Sample size calculation two groups of 20 subjects will be enrolled. 