Determinants of restoration of CD4 and CD8 cell counts and their ratio in HIV-1 positive individuals with sustained virological suppression on antiretroviral therapy by Gras, L, May, M, Ryder, L, Trickey, A, Helleberg, M, Obel, N, Thiebaut, R, Guest, J, Gill, J, Crane, H, Lima, V, Monforte, A, Sterling, T, Miro, J, Moreno, S, Stephan, C, Smith, C, Tate, J, Shepherd, L, Saag, M, Rieger, A, Gillor, D, Cavassini, M, Montero, M, Ingle, S, Reiss, P, Costagliola, D, Wit, F, Sterne, J, De Wolf, F, Geskus, R, Antiretroviral Therapy Cohort Collaboration (ART-CC)