Tremendous success in the prevention and treatment of pediatric HIV in high-resource countries has changed the face of the epidemic. A perinatally HIV-infected child now faces a chronic disease rather than a progressive, fatal one. However, these successes pose new challenges as perinatally HIV-infected youth survive into adulthood. These include maintaining adherence to long-term, likely life-long therapy; selecting successive antiretroviral drug regimens, given the limited availability of pediatric formulations and the lack of pharmacokinetic and safety data in children; and overcoming extensive drug resistance in multi-drug-experienced children. Pediatric HIV care now focuses on morbidity related to long-term HIV infection and its treatment. Survival into adulthood of perinatally HIV-infected youth in high-resource countries encourages expansion of pediatric treatment programs in low-resource countries, where most HIV-infected children live, and provides important lessons about how the epidemic changes with increasing access to antiretroviral therapy for children.

The most common manifestation of infection due to nontuberculous mycobacteria (NTM) in children is cervical lymphadenitis in an otherwise healthy patient. We identified and reviewed 19 cases of proven or presumptive lymphadenitis due to NTM seen at our hospital over the course of 13 months. Nine patients underwent initial surgical excision of involved lymph nodes. Ten children did not have involved lymph nodes excised initially and were treated with macrolide-containing antibiotic regimens. Of these patients, five required subsequent surgical excision and five were cured with combination chemotherapy. Six patients underwent radiographic imaging of the head and neck that revealed asymmetrical adenopathy with ring-enhancing masses but minimal inflammatory stranding of the subcutaneous fat, a finding that may distinguish adenitis caused by NTM from staphylococcal and streptococcal adenitis. Our data suggest that if surgical excision is not considered feasible, antimicrobial therapy for adenitis due to NTM may be beneficial for some patients.

Tenofovir disoproxil fumarate use in children seems to be associated with decreases in bone mineral density that, in some children, stabilize after 24 weeks. Increases in bone markers and calcium excretion suggest that tenofovir disoproxil fumarate may stimulate bone resorption. Bone turnover is higher in children than in older adolescents and adults because of skeletal growth, potentially explaining the greater effect seen in young children. Decreases in bone mineral density correlate with decreases in viral load and young age, suggesting that young responders may be at greater risk for bone toxicity.

The global paediatric HIV epidemic is shifting into a new phase as children on antiretroviral therapy (ART) move into adolescence and adulthood, and face new challenges of living with HIV. UNAIDS reports that 3.4 million children aged below 15 years and 2 million adolescents aged between 10 and 19 years have HIV. Although the vast majority of children were perinatally infected, older children are combined with behaviourally infected adolescents and youth in global reporting, making it difficult to keep track of their outcomes. Perinatally HIV-infected adolescents (PHIVA) are a highly unique patient sub-population, having been infected before development of their immune systems, been subject to suboptimal ART options and formulations, and now face transition from complete dependence on adult caregivers to becoming their own caregivers. As we are unable to track long-term complications and survival of PHIVA through national and global reporting systems, local and regional cohorts are the main sources for surveillance and research among PHIVA. This global review will utilize those data to highlight the epidemiology of PHIVA infection, treatment challenges and chronic disease risks. Unless mechanisms are created to count and separate out PHIVA outcomes, we will have few opportunities to characterize the negative consequences of life-long HIV infection in order to find ways to prevent them.

Mental health problems (MHPs) among children with perinatal HIV infection have been described prior to and during the highly active antiretroviral therapy (HAART) era. Yet child, caregiver and socio-demographic factors associated with MHPs are not fully understood. We examined the prevalence of MHPs among older children and adolescents with perinatal HIV exposure, including both perinatally HIV-infected (PHIV+) and perinatally HIV-exposed but uninfected (PHEU) youth. Our aims were to identify the impact of HIV infection by comparing PHIV+ and PHEU youth and to delineate risk factors associated with MHPs, in order to inform development of appropriate prevention and intervention strategies. Youth and their caregivers were interviewed with the Behavior Assessment System for Children, 2nd edition (BASC-2) to estimate rates of at-risk and clinically significant MHPs, including caregiver-reported behavioral problems and youth-reported emotional problems. The prevalence of MHPs at the time of study entry was calculated for the group overall, as well as by HIV status and by demographic, child health, and caregiver characteristics. Logistic regression models were used to identify factors associated with youth MHPs. Among 416 youth enrolled between March 2007 and July 2009 (295 PHIV+, 121 PHEU), the overall prevalence of MHPs at entry was 29% and greater than expected based on recent national surveys of the general population. MHPs were more likely among PHEU than among PHIV+ children (38% versus 25%, p < 0.01). Factors associated with higher odds of MHPs at p < 0.10 included caregiver characteristics (psychiatric disorder, limit-setting problems, health-related functional limitations) and child characteristics (younger age and lower IQ). These findings suggest that PHEU children are at high risk for MHPs, yet current models of care for these youth may not support early diagnosis and treatment. Family-based prevention and intervention programs for HIV affected youth and their caregivers may minimize long-term consequences of MHPs.

Mycobacterium tuberculosis, an obligate mammalian pathogen, adapts to its host during the course of infection via the regulation of gene expression. Of the regulators of transcription that play a role in this response, several alternative sigma factors of M. tuberculosis have been shown to control gene expression in response to stresses, and some of these are required for virulence or persistence in vivo. For this study, we examined the role of the alternative sigma factor SigD in M. tuberculosis gene expression and virulence. Using microarray analysis, we identified several genes whose expression was altered in a strain with a sigD deletion. A small number of these genes, including sigD itself, the gene encoding the autocrine growth factor RpfC, and a gene of unknown function, Rv1815, appear to be directly regulated by this sigma factor. By identifying the in vivo promoters of these genes, we have determined a consensus promoter sequence that is putatively recognized by SigD. The expression of several genes encoding PE-PGRS proteins, part of a large family of related genes of unknown function, was significantly increased in the sigD mutant. We found that the expression of sigD is stable throughout log phase and stationary phase but that it declines rapidly with oxygen depletion. In a mouse infection model, the sigD mutant strain was attenuated, with differences in survival and the inflammatory response in the lung between mice infected with the mutant and those infected with the wild type.Mycobacterium tuberculosis is an obligate mammalian pathogen that is believed to infect roughly one-third of the world's population (33). While capable of causing disease in a substantial proportion of those infected, resulting in approximately eight million cases of active tuberculosis in the world each year, this bacillus causes an asymptomatic infection in most individuals. After an initial period of rapid replication, the infection is typically contained by the host immune system, resulting in the apparent eradication of the infection in some individuals but in the persistence of small numbers of bacteria in others, resulting in asymptomatic chronic infections. These latent infections may subsequently become active, often in the setting of decreased host immunity, with increased bacterial replication and extensive tissue damage.During these several stages of infection, M. tuberculosis encounters a changing host environment, in response to which the bacillus must activate defense and repair mechanisms and reprogram its physiology to ensure survival. The large number of putative transcription regulators identified in the M. tuberculosis genome sequence indicate that much of the regulation required for these adaptations by M. tuberculosis occurs at the level of transcription (6). Among the transcription regulators that have been implicated in these processes are the alternative sigma factors of this organism, 12 of which are encoded in the M. tuberculosis genome. In previous work, our laboratory and others have implicated sev...

Protease inhibitor use early in pregnancy may be associated with increased risk for prematurity.

Mutational escape from the CTL response represents a major driving force for viral diversification in HIV-1-infected adults, but escape during infancy has not been described previously. We studied the immune response of perinatally infected children to an epitope (B57-TW10) that is targeted early during acute HIV-1 infection in adults expressing HLA-B57 and rapidly mutates under this selection pressure. Viral sequencing revealed the universal presence of escape mutations within TW10 among B57- and B5801-positive children. Mutations in TW10 and other B57-restricted epitopes arose early following perinatal infection of B57-positive children born to B57-negative mothers. Surprisingly, the majority of B57/5801-positive children exhibited a robust response to the TW10 escape variant while recognizing the wild-type epitope weakly or not at all. These data demonstrate that children, even during the first years of life, are able to mount functional immune responses of sufficient potency to drive immune escape. Moreover, our data suggest that the consequences of immune escape may differ during infancy because most children mount a strong variant-specific immune response following escape, which is rarely seen in adults. Taken together, these findings indicate that the developing immune system of children may exhibit greater plasticity in responding to a continually evolving chronic viral infection.