The study analyzes the virological response in plasma and non-plasma compartments, as well as the degree and kinetics of immune reconstitution in 70 treatment-naive patients with CD4 < 100/mm3, when they receive treatment with two nucleoside analogs (NRTI) plus one protease inhibitor (PI) compared with 2 NRTI plus one non-nucleoside (NNRTI).

Inclusion Criteria:

• Diagnosed HIV-1 infection.
• Age 18 years or over.
• No previous antiretroviral therapy.
• CD4 lymphocyte count of < 100 cells/mL.
• Patients who, sufficiently informed, give their written consent to participate in the study and undergo the tests and explorations involved in the study.

Exclusion Criteria:

• Pregnant women, women who are breast feeding, or women who intend to become pregnant during the study period.
• Currently undergoing treatment for an opportunistic infection (parenteral administration).
• Any formal contraindication to treatment with the study drugs