Natural history of HIV infected pediatric long-term or slow progressor population after the first decade of life.

BACKGROUND: Perinatally infected long-term nonprogressors/slow progressors represent a select group of individuals. There is very limited information on this group of children beyond the first decade of life. A group of HIV-infected long-term nonprogressor/slow progressor children was studied. METHODS: We enrolled 20 HIV-infected adolescents who were receiving no or minimal therapy (defined as single or dual nucleoside therapy) before the age of 10 years and who had maintained CD4 counts above 25% for the first decade of life. We analyzed immunologic and virologic characteristics. Thymic receptor excision circles (TREC) were measured on stored frozen peripheral blood mononuclear cells. CD4 count, viral load and other pertinent information including race and age were obtained from individual medical records. RESULTS: Nine of the 20 patients recruited were noted to have developed falling CD4 counts at or around puberty, whereas the other 11 remained stable. There was no difference in TREC values or HIV RNA values before or after puberty between the 2 groups of patients. Those who remained stable, in terms of maintaining CD4 T cells as a group had falling viral loads with age. Those whose CD4 values declined after puberty had viral loads that did not decrease with age. CONCLUSION: A select group of patients who never received HAART during their first decade of life will continue to maintain good CD4 associated with declining HIV RNA values. Thymic output is not predictive of those that don't maintain CD4 T cells.

CCR5 expression and duration of high risk sexual activity among HIV-seronegative men who have sex with men.

OBJECTIVES: To test the hypothesis that in comparison with those with shorter risk duration, individuals with longer HIV risk duration would have reduced susceptibility to HIV-1 infection as measured by CCR5 expression, and to evaluate whether variation in CCR5 expression could be explained by known genetic polymorphisms. DESIGN AND METHODS: A cross-sectional study of HIV-1 exposed but uninfected men who have sex with men. The risk duration was estimated from self-reported years since first receptive anal intercourse. CCR5 expression on peripheral blood CD4+ monocytes and T cells was determined by flow cytometry. The CCR5-Delta32 mutation and polymorphisms in the CCR5 promoter and CCR2 as well as the copy number of CCL3L1 were analyzed by polymerase chain reaction. Plasma levels of MIP-1alpha (CCL3), MIP-1beta (CCL4) and RANTES (CCL5) were also measured. As risk duration varied with age, analyses were restricted to 67 individuals aged 30-49 years. RESULTS: Multiple linear regression analyses, adjusted for age and race, showed a significant negative association between HIV risk duration and CCR5 expression on monocytes (P = 0.01), and in a separate model, a similar negative association with CCR5 expression on T cells (P = 0.03). Low CCR5 expression was attributable mainly to CCR5-Delta32 heterozygosity and the CCR5-59029G allele. CONCLUSIONS: We confirmed a role for reduced CCR5 expression in HIV-1 resistance. CCR5-Delta32 heterozygosity and the CCR5-59029G allele were significant predictors of low CCR5 expression. Individuals with high CCR5 expression who resisted infection despite long HIV risk duration form an interesting group within which to search for additional mechanisms of resistance to HIV infection.

Development of a molecular-beacon assay to detect the G1896A precore mutation in hepatitis B virus-infected individuals.

The 1896 precore (PC) mutation is the most frequent cause of hepatitis B virus e-antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infection. Detection of the 1896 PC mutation has application in studies monitoring antiviral therapy and the natural history of the disease. Identification of this mutation is usually performed by direct sequencing, which is both costly and laborious. The aim of this study was to develop a rapid, high-throughput assay to detect the 1896 PC mutation using real-time PCR and molecular-beacon technology. The assay was initially standardized on oligonucleotide targets and plasmids containing the wild-type (WT) and PC mutation and then tested on plasma samples from children with HBV DNA of >10(6) copies/ml. Nine individuals were HBeAg negative and suspected to harbor HBeAg mutations, while 12 children were HBeAg positive and selected as controls. Ninety percent (19 of 21) of plasma samples tested with molecular beacons were in complete agreement with sequencing results. The remaining 10% (2 of 21) of samples were identified as heterogeneous mixtures of WT and mutant virus by molecular beacons, though sequencing found only a homogeneous mutant in both cases. Overall, the 1896 PC mutation was detected by this assay in 55.5% of the children with HBeAg-negative infection. In summary, this assay is a rapid, sensitive, and specific technique that effectively discriminates WT from 1896 PC mutant HBV and may be useful in clinical and epidemiological studies.

Mycobacterium tuberculosis-induced CXCR4 and chemokine expression leads to preferential X4 HIV-1 replication in human macrophages.

Opportunistic infections such as pulmonary tuberculosis (TB) increase local HIV-1 replication and mutation. As AIDS progresses, alteration of the HIV-1 gp120 V3 sequence is associated with a shift in viral coreceptor use from CCR5 (CD195) to CXCR4 (CD184). To better understand the effect of HIV/TB coinfection, we screened transcripts from bronchoalveolar lavage cells with high density cDNA arrays and found that CXCR4 mRNA is increased in patients with TB. Surprisingly, CXCR4 was predominately expressed on alveolar macrophages (AM). Mycobacterium tuberculosis infection of macrophages in vitro increased CXCR4 surface expression, whereas amelioration of disease reduced CXCR4 expression in vivo. Bronchoalveolar lavage fluid from TB patients had elevated levels of CCL4 (macrophage inflammatory protein-1beta), CCL5 (RANTES), and CX3CL1 (fractalkine), but not CXCL12 (stromal-derived factor-1alpha). We found that M. tuberculosis infection of macrophages in vitro increased viral entry and RT of CXCR4-using [corrected] HIV-1, but not of CCR5-using [corrected] HIV-1. Lastly, HIV-1 derived from the lung contains CD14, suggesting that they were produced in AM. Our results demonstrate that TB produces a permissive environment for replication of CXCR4-using virus by increasing CXCR4 expression in AM and for suppression of CCR5-using HIV-1 by increasing CC chemokine expression. These changes explain in part why TB accelerates the course of AIDS. CXCR4 inhibitors are a rational therapeutic approach in HIV/TB coinfection.

Response to lamivudine treatment in children with chronic hepatitis B virus infection.

Despite the recent approval of lamivudine for the treatment of children with chronic hepatitis B virus (HBV) infection, there is insufficient information on the kinetics of HBV clearance and the factors that predict a favorable treatment response to lamivudine in this population. In a small retrospective study of 16 HBV-infected children treated with lamivudine, we examined changes in virus load and other factors associated with hepatitis B e antigen (HBeAg) clearance. High pretherapy alanine aminotransferase level, low serum HBV DNA load, and age at the start of treatment were independently associated with HBeAg clearance. HBeAg clearance was also associated with the achievement of specific levels of virus suppression, and failure to achieve those levels was associated with the development of lamivudine resistance. Additional studies are necessary to provide better indications and guidelines for the treatment of children with chronic HBV infection.