Objectives: To evaluate whether successful, long-term immune reconstitution in vivo can be achieved in end-stage AIDS patients following antiretroviral therapy (ART).
Methods: A 1-year prospective study of changes of CD4+ and CD8+ T-cell surface phenotypes, T-cell receptor (TCR) repertoires and capacity to control in vivo replication of cytomegalovirus (CMV) was performed in five treatment-naive end-stage AIDS patients (median CD4+ T-cell counts of 19 cells/microL) following therapy. Proportions of CD45RA+, CD45RO+ and CD28+ cells within the CD4+ and CD8+ subsets, were determined by flow cytometry. Changes in TCR Vbeta repertoires within the CD4+ and CD8+ T-cell compartments were evaluated using CDR3 spectratyping. CMV replication was determined by a sensitive polymerase chain reaction (PCR) assay using whole blood.
Results: Following ART, proportionate increases in 'naive' (CD45RA+) and 'memory' (CD45RO+) T cells were observed within both CD4+ and CD8+ T-cell subsets, while increased numbers of CD28+ T cells were mainly observed within the CD4+ subset. Diversification of CD4+ and CD8+ TCR repertoires was established concomitantly with renewed in vivo control of CMV replication.
Conclusions: An important degree of molecular and functional immune recovery is possible in end-stage AIDS patients introduced to therapy. Diversification of TCR repertoires and the in vivo restoration of immunocompetence to control opportunistic infections clearly show that an important degree of molecular immune reconstitution is established following the initiation of ART even in late-stage AIDS.