Appearance of a single amino acid insertion at position 33 in HIV type 1 protease under a lopinavir-containing regimen, associated with reduced protease inhibitor susceptibility. by Magiorkinis, E, Paraskevis, D, Detsika, MG, Lu, L, Magiorkinis, G, Lazanas, M, Imbrechts, S, Van Laethem, K, Vandamme, A, Vandamme, A, Pilot-Matias, T, Molla, A, Camacho, R, Hatzakis, A