Dissociation of Responses to Highly Active Antiretroviral Therapy: Notwithstanding Virologic Failure and Virus Drug Resistance, Both CD4+ and CD8+ T Lymphocytes Recover in HIV-1 Perinatally Infected Children:

Perinatal human immunodeficiency virus type-1 in the 21st century: new challenges in treatment and health care organization

In the industrialized world, extraordinary successes have been attained in reducing mother-to-child HIV transmission and improving the survival of children with HIV infection; however, significant challenges remain.

Incomplete immune reconstitution despite virologic suppression in HIV-1 infected children and adolescents

OBJECTIVES

Some perinatally infected children do not regain normal CD4(+) T-cell counts despite suppression of HIV-1 plasma viremia by antiretroviral therapy (ART). The frequency, severity and significance of these discordant treatment responses remain unclear.

DESIGN

We examined the persistence of CD4(+) lymphocytopenia despite virologic suppression in 933 children (≥ 5 years of age) in the USA, Latin America and the Caribbean.

METHODS

CD4(+) T-cell trajectories were examined and Kaplan-Meier methods used to estimate median time to CD4(+) T-cell count at least 500 cells/μl.

RESULTS

After 1 year of virologic suppression, most (99%) children achieved a CD4(+) T-cell count of at least 200 cells/μl, but CD4(+) T-cell counts remained below 500 cells/μl after 1 and 2 years of virologic suppression in 14 and 8% of children, respectively. Median times to first CD4(+) T-cell count at least 500 cells/μl were 1.29, 0.78 and 0.46 years for children with less than 200, 200-349 and 350-499 cells/μl at the start of virologic suppression. New AIDS-defining events occurred in nine children, including four in the first 6 months of virologic suppression. Other infectious and HIV-related diagnoses occurred more frequently and across a wide range of CD4(+) cell counts.

CONCLUSION

ART improved CD4(+) cell counts in most children, but the time to CD4(+) cell count of at least 500 cells was highly dependent upon baseline immunological status. Some children did not reach a CD4(+) T-cell count of 500 cells/μl despite 2 years of virologic suppression. AIDS-defining events occurred in 1% of the population, including children in whom virologic suppression and improved CD4(+) T-cell counts were achieved.

Immunological recovery despite virological failure is independent of human immunodeficiency virus-type 1 resistant mutants in children receiving highly active antiretroviral therapy

Relationships between human immunodeficiency virus-type-1 (HIV-1) drug-resistant mutants and immunological recovery were investigated after 12-week antiretroviral therapy in 43 children infected perinatally with virological failure. Twenty-two children received highly active antiretroviral therapy (HAART) and 21 received double therapy with reverse transcriptase inhibitors. At baseline, no difference in reverse transcriptase or protease inhibitors resistant mutants was present among the groups. After 12 weeks, the two groups were similar regarding proportion of children with reverse transcriptase resistant mutants. Sixteen (73%) HAART-treated children, but no child receiving double therapy had HIV-1 with primary resistance mutations to protease inhibitors. Secondary protease mutations were found in all HAART-treated and in 17/21 (81%) children receiving double therapy. The mutation numbers in reverse transcriptase or protease genes were significantly higher after HAART than after double therapy. Nevertheless, 12 (55%) of HAART-treated children (but no child receiving double therapy) showed immunological recovery. The frequency and number of mutations were similar in HAART-treated children with or without immunological recovery both at baseline and after 12 weeks. The findings suggest, immunological recovery notwithstanding, virological failure is independent of drug-resistant mutations and consequent possible changes in viral fitness.

Reduced frequency of wheezing respiratory illness in infants with perinatal human immunodeficiency virus-type 1 infection: a model for immunologic and inflammatory mechanisms of airway obstruction?

A multivariate analysis using a logistic regression model evaluated odds ratio (OR) and 95% confidence limits (95% CL) of pediatrician-diagnosed wheezing respiratory illness in 75 infants with perinatal human immunodeficiency virus-type 1 (HIV-1) infection, 205 uninfected infants of HIV-1 infected mothers, and 1780 infants of HIV-1 uninfected mothers. Infants were prospectively followed-up for the first 2 years of life. Covariates were risk factors for wheezing respiratory illness (preterm delivery, low birth weight, maternal smoking, formula feeding, and neonatal respiratory disorders). Maternal use of illicit drugs in pregnancy, antiretroviral treatment in pregnancy, maternal HIV-1-related clinical condition at the time of delivery were also included in the models when infants of HIV-1 infected mothers were taken into account. Although the frequency of risk factors for wheezing respiratory illness was higher in infants of HIV-1 infected than in those of uninfected mothers, HIV-1 infection emerged as a protective factor [OR: 0.001 (95% CL: 0.0001-0.01); p < 0.001]. The frequency of risk factors was similarly high among infants of infected mothers, but OR was lower in HIV-1 infected than in uninfected infants of infected mothers (0.005; 95% CL: 0.0004-0.06; p < 0.001). Finally, OR was higher in uninfected infants of HIV-1 infected mothers (who evidenced a higher frequency of risk factors) than in infants of HIV-1 uninfected mothers (9.97; 95% CL: 4.87-20.40; p < 0.001). Understanding the reason why HIV-1 protects against wheezing respiratory illness could shed light on the immunologic and inflammatory mechanisms of airway obstruction.