Publications

New cell types and cytokines have emerged as key participants in the elaboration of and recovery from inflammation. A collection of reviews covers recent advances in our understanding of this crucial component of host defense.

Naive T lymphocytes acquire a phenotype similar to Ag-experienced memory T cells as a result of proliferation under lymphopenic conditions. Such "memory-like" T (T(ML)) cells constitute a large fraction of the peripheral T cell pool in patients recovering from T cell ablative therapies, HIV patients under highly active antiretroviral therapy, and in the elderly population. To generate a model that allows characterization of T(ML) cells without adoptive transfer, irradiation, or thymectomy, we developed genetically modified mice that express diphtheria toxin A under control of a loxP-flanked stop cassette (R-DTA mice). Crossing these mice to CD4Cre mice resulted in efficient ablation of CD4 single-positive thymocytes, whereas double-positive and CD8 single-positive thymocytes were only partially affected. In the periphery the pool of naive (CD44(low)CD62L(high)) T cells was depleted. However, some T cells were resistant to Cre activity, escaped deletion in the thymus, and underwent lymphopenia-induced proliferation resulting in a pool of T(ML) cells that was similar in size and turnover to the pool of CD44(high)CD62L(low) "memory phenotype" T cells in control mice. CD4Cre/R-DTA mice remained lymphopenic despite the large available immunological "space" and normal Ag-induced T cell proliferation. CD4Cre/R-DTA mice showed a biased TCR repertoire indicating oligoclonal T cell expansion. Infection with the helminth Nippostrongylus brasiliensis resulted in diminished effector cell recruitment and impaired worm expulsion, demonstrating that T(ML) cells are not sufficient to mediate an effective immune response.

The use of tobacco remains a significant public health concern among Asian American (AA) adolescents. Understanding the factors that affect smoking progression among Chinese and Vietnamese adolescents in particular, may help in illuminating potential interventions that can be implemented to maximize scarce programming and resources. This study is a longitudinal cohort study with data collected in California via telephone over a two-year period. 1,270 Chinese and Vietnamese American adolescents were recruited via telephone listings from one southern and four northern California counties. Main outcomes were smoking susceptibility and change in smoking status. Examination of these adolescents indicated that in both groups: boys were more likely than girls to become susceptible to smoking, risk behaviors were associated with becoming smokers, having been susceptible at baseline was associated with susceptibility and smoking at follow-up, and the influence of friends was a predictor of susceptibility and smoking.

BACKGROUND

There is growing interest in the use of interactive telephone technology to support chronic disease management. We used the implementation of an automated telephone self-management support program for diabetes patients as an opportunity to monitor patient safety.

METHODS

We identified adverse and potential adverse events among a diverse group of diabetes patients who participated in an automated telephone health-IT self-management program via weekly interactions augmented by targeted nurse follow-up. We defined an adverse event (AE) as an injury that results from either medical management or patient self-management, and a potential adverse event (PotAE) as an unsafe state likely to lead to an event if it persists without intervention. We distinguished between incident, or new, and prevalent, or ongoing, events. We conducted a medical record review and present summary results for event characteristics including detection trigger, preventability, potential for amelioration, and primary care provider awareness.

RESULTS

Among the 111 patients, we identified 111 AEs and 153 PotAEs. Eleven percent of completed calls detected an event. Events were most frequently detected through health IT-facilitated triggers (158, 59%), followed by nurse elicitation (80, 30%), and patient callback requests (28, 11%). We detected more prevalent (68%) than incident (32%) events. The majority of events (93%) were categorized as preventable or ameliorable. Primary care providers were aware of only 13% of incident and 60% of prevalent events.

CONCLUSIONS

Surveillance via a telephone-based, health IT-facilitated self-management support program can detect AEs and PotAEs. Events detected were frequently unknown to primary providers, and the majority were preventable or ameliorable, suggesting that this between-visit surveillance, with appropriate system-level intervention, can improve patient safety for chronic disease patients.

BACKGROUND

Artemisinin-based combination therapies are rapidly being adopted for the treatment of malaria in Africa; however, there are limited data on their safety and efficacy among human immunodeficiency virus (HIV)-infected populations.

METHODS

We compared malaria treatment outcomes between cohorts of HIV-infected and HIV-uninfected children in Uganda who were observed for 18 and 29 months, respectively. Malaria was treated with artesunate plus amodiaquine, and outcomes were assessed using standardized guidelines. HIV-infected children received trimethoprim-sulfamethoxazole prophylaxis and antiretroviral therapy in accordance with current guidelines.

RESULTS

Twenty-six HIV-infected participants experiencing 35 episodes of malaria and 134 HIV-uninfected children experiencing 258 episodes of malaria were included in the study. Twelve HIV-infected children were receiving antiretroviral therapy, 11 of whom were receiving zidovudine. Malaria treatment was highly efficacious in both the HIV-infected and HIV-uninfected cohorts (28-day risk of recrudescence, 0% and 3.6%, respectively); however, there was a trend towards increased risk of recurrent malaria among the HIV-uninfected children (2.9% vs. 13.2%; p = .08). Importantly, the risk of neutropenia 14 days after initiation of treatment with artesunate plus amodiaquine was higher among HIV-infected children than among HIV-uninfected children (45% vs. 6%; p < .001). The severity of all episodes of neutropenia in HIV-uninfected children was mild to moderate, and 16% of episodes of neutropenia in the HIV-infected cohort were severe or life-threatening (neutrophil count, <750 cells/mm(3)). In the HIV-infected cohort, the risk of neutropenia was significantly higher among children who received antiretroviral therapy than among those who did not receive antiretroviral therapy (75% vs. 26%; p < .001).

CONCLUSIONS

Artesunate plus amodiaquine was highly efficacious for malaria treatment in HIV-infected children but was associated with a high risk of neutropenia, especially in the context of concurrent antiretroviral use. Our findings highlight an urgent need for evaluation of alternative antimalarial therapies for HIV-infected individuals.

Osteopenia and periarticular bony erosion are consequences of chronic inflammatory autoimmune disease due to an imbalance of osteoclast activity relative to new bone formation. Osteoclasts, which are specialized as the only bone resorbing cell type, are differentiated from hematopoietic myeloid precursor cells. Inflammatory signals mediated by multiple types of immune cells and cytokines have significant influence over osteoclast differentiation and function through direct effects on osteoclast precursors and indirect effects via osteoblasts and other cells in the bony microenvironment including synovial cells, stromal cells, osteocytes and chondrocytes. Recent studies have demonstrated that osteoclasts themselves express a number of immune receptors and are regulated similarly to macrophages and dendritic cells, closely related cells in the innate immune system. Though we are only beginning to understand the roles of innate immune receptors in osteoclasts, some of these receptors have been shown to be critical regulators of differentiation and function of osteoclasts. Osteoclasts likely function as the innate immune cells of the bone, thus are highly regulated to appropriately respond to stress and inflammatory changes in their microenvironment.

Asthma is a common but complex respiratory disease caused by the interaction of genetic and environmental factors. Significant racial and ethnic disparities in prevalence, mortality and drug response have been described. These disparities may be explained by racial and ethnic-specific variation in genetic, environmental, social and psychological risk factors. In addition, race, ethnicity and social class are important proxies for unmeasured factors that influence health outcomes. Herein, we review salient differences in the etiologies of asthma by race, ethnicity and social class, and argue for their continued use as variables in asthma research.