Influence of repeated cycles of structured therapy interruption on the rate of recovery of CD4+ T cells after highly active antiretroviral therapy resumption.

BACKGROUND: CD4+ T cell recovery dynamics were analysed during the 'on treatment' periods in structured therapy interruption (STI) as well as the long-term immune reconstitution with highly active antiretroviral therapy (HAART) after finishing STI. METHODS: One hundred and twenty HIV-1-infected patients on successful HAART were randomized to receive for 2 years continuous HAART (n=37) or two different strategies of STI (n=83). After this period, most patients received continuous HAART for 2 years. RESULTS: During the STI period, the rate of recovery of CD4+ T cells decreased progressively from the first to the last resumption of HAART {median change of increase: +232 [interquartile range (IQR): +126, +318], +116 (IQR: +10, +471), +87 (IQR: -54, +252) and -26 (IQR: -352, +211) cells/mm3 after the first, second, third and fourth resumption, respectively}. After the STI period and 2 years of continuous HAART, the median CD4+ count remained significantly lower than at baseline in STI arms, both in the virological arm [559 (IQR: 383, 727) versus 771 (IQR: 625, 913) cells/mm3, P<0.0001] and the immunological arm [619 (IQR: 501, 789) versus 787 (IQR: 657, 954) cells/mm3, P<0.0001], but not in the control arm [886 (IQR: 564, 1122) versus 780 (IQR: 539, 945) cells/mm3, P=0.68]. In a multivariate analysis, the nadir of CD4+ T cells and the baseline value of CD4+ before the STI period independently predicted the level of CD4+ T cells 2 years after resumption of HAART (in both cases, P<0.0001). CONCLUSION: The drop in CD4+ cell count after a first and a second period of 3 months of interruption of HAART was completely recovered after resuming HAART; conversely, interruptions longer than 6 months were deleterious for the recovery of CD4+. CD4+ cell count did not rebound completely in patients who received 2 years of HAART after 2 years of STIs.

Short Communication: Natural killer cells and expression of KIR receptors in chronic HIV type 1-infected patients after different strategies of structured therapy interruption.

Few data evaluating the NK cell profile during structured therapy interruption (STI) in chronic HIV-1 infection are available. Changes in NK cell percentages and KIR and NKG2A receptors were analyzed at baseline and after 2 years of follow-up in 121 patients on ART with CD4(+) >450 cells/ml and VL <200 copies/ml randomized in three arms according to the criteria employed to resume ART during STI: virological arm (VA n = 47, VL >30,000 copies/ml or CD4 <350 cells/ml), immunological arm (IA n = 37, CD4< 350 cells/ml), and a control arm (n = 37) in which ART was maintained. After 2 years of follow-up, a decrease in CD3(-)CD56(+) CD16(+) cell percentages in VA and IA patients, but not in CA patients, was observed. Those patients with higher decrease in CD3(-)CD56(+)CD16(+) cells had a higher decrease in CD4(+) cells (r = 0.35, p = 0.001) and higher increase in PVL (r = -0.26, p = 0.02). KIR and NKG2A receptor expression tended to increase in CA and decreased in the other two arms (more in IA than in VA). Patients who displayed a greater decrease in CD4(+) T cells and a greater rise in PVL after 2 years of follow-up had a significantly higher decrease in KIR and NKG2A receptors expressed in CD3(-)CD56(+) cells. Patients who presented the lowest levels of total NK cells and KIR and NKG2A receptor expression after STI showed the poorest virology or immunology outcomes. This finding suggests that STI could decrease the number of NK subsets, which is related to the worst clinical development in these patients.