Increased proliferation within T lymphocyte subsets of HIV-infected adolescents.

Proliferation within T lymphocyte subsets of HIV-infected adolescents was quantified by detection of Ki-67, a nuclear antigen found in cells in late G(1), S, or G(2) phases of the cell cycle. Median percentages and absolute counts of Ki-67(+) cells for all subsets tested (CD4 naive and memory, CD8 naive and memory) were significantly higher for HIV-infected adolescents compared to uninfected controls. CD8 naive cells of HIV-infected adolescents had the greatest increase in rate of proliferation and number of proliferating cells compared to uninfected controls. In HIV-infected adolescents, the percentage and absolute number of proliferating CD4 naive cells were considerably lower than corresponding values for the other subsets. CD4 percent correlated inversely with Ki-67 expression in CD4 memory, CD8 naive, and CD8 memory cells, while Ki-67 expression in CD4 and CD8 memory cells correlated directly with average CD38 molecules/CD8 cell and absolute number of CD8/CD38/HLA-DR cells, consistent with T cell activation. These results indicate that in adolescents, HIV infection is associated with increased proliferation within CD4 and CD8 naive and memory subsets. Proliferation within the CD8 naive subset was higher than that observed previously for HIV-infected adults, suggesting that adolescents have a greater ability to regenerate and/or expand CD8 naive cells. CD4 naive cells of HIV-infected adolescents had a low rate of proliferation, and the total number of CD4 naive cells was low, suggesting that regeneration and/or peripheral expansion are limited and may contribute to the reduced size of this subset. The Ki-67 assay provided new and useful information on in vivo lymphocyte proliferation in HIV-infected adolescents.

Enhanced psychosocial well-being following participation in a mindfulness-based stress reduction program is associated with increased natural killer cell activity.

BACKGROUND: Mindfulness-based stress reduction (MBSR) programs have consistently been shown to enhance the psychosocial well-being of participants. Given the well-established association between psychosocial factors and immunologic functioning, it has been hypothesized that enhanced psychosocial well-being among MBSR participants would be associated with corresponding changes in markers of immune activity. OBJECTIVES: The objectives of this study were to examine changes in psychosocial and immunologic measures in a heterogeneous patient sample following participation in a MBSR program. DESIGN: A single-group, pretest/post-test design was utilized. SETTING: The intervention was conducted at an academic health center. SUBJECTS: This pilot study involved 24 participants (aged 28-72 years). Inclusion criteria were as follows: > or =18 years of age, English-speaking, and no known autoimmune disorder. INTERVENTION: The intervention was an 8-week MBSR program. OUTCOME MEASURES: Distress and quality of life (QOL) measures included the Brief Symptom Inventory-18 and the Medical Outcomes Survey Short-Form Health Survey, respectively. Immunologic measures included natural killer (NK) cell cytolytic activity and C-reactive protein (CRP). RESULTS: Patients completed psychosocial assessments and provided a blood sample at baseline (pre-MBSR) and within 2 weeks post-MBSR. Significant improvements in anxiety and overall distress as well as across multiple domains of QOL were observed from baseline to post-MBSR. Reductions in anxiety and overall distress were associated with reductions in CRP. Patients who reported improvement in overall mental well-being also showed increased NK cytolytic activity from pre- to post-MBSR, whereas patients who reported no improvement in mental well-being showed no change in NK cytolytic activity. CONCLUSIONS: Positive improvement in psychologic well-being following MBSR was associated with increased NK cytolytic activity and decreased levels of CRP.

Novel method for determination of substance P levels in unextracted human plasma by using acidification.

Substance P (SP) is a member of the tachykinin family and has an important role in immune responses. SP is detectable in plasma in a free and bound state. Simple modification of a commercially available SP enzyme-linked immunosorbent assay allows the dissociation and capture of plasma SP without solid-phase extraction.

Perceived stress is associated with impaired T-cell response to HPV16 in women with cervical dysplasia.

BACKGROUND: Infection with high-risk subtypes of human papillomavirus (HPV) is a central factor in the development of cervical neoplasia. Cell-mediated immunity against HPV16 plays an important role in the resolution of HPV infection and in controlling cervical disease progression. Research suggests that stress is associated with cervical disease progression, but few studies have examined the biological mechanisms that may be driving this association. PURPOSE: This study examines whether stress is associated with immune response to HPV16 among women with cervical dysplasia. METHODS: Seventy-four women presenting for colposcopy completed measures of health behaviors, stressful life events and perceived stress. A blood sample was obtained to evaluate proliferative T-cell response to HPV16, and a cervical sample was obtained during gynecologic exam for HPV-typing. RESULTS: More than 55% tested positive for one or more HPV subtypes. Women who did not show proliferative responses to HPV (i.e. non-responders) were more likely to be HPV(+) compared to women who had a response (i.e. responders). Consistent with study hypotheses, logistic regression revealed that higher levels of perceived stress were associated with a non-response to HPV16, controlling for relevant covariates. Stressful life events were not associated with T-cell response to HPV. CONCLUSIONS: Higher levels of perceived stress are associated with impaired HPV-specific immune response in women with cervical dysplasia, suggesting a potential mechanism by which stress may influence cervical disease progression.

Measurement of plasma-derived substance P: biological, methodological, and statistical considerations.

The undecapeptide substance P (SP) is a member of the tachykinin family of neurotransmitters, which has a pivotal role in the regulation of inflammatory and immune responses. One of the major barriers to the study of the in vivo role of SP in a number of immune disorders is the accurate measurement of SP in fluids. This is reflected in the variability of reported SP levels in serum and plasma of humans in both healthy and diseased states. This study was initiated in order to identify sources of variability by the comparative evaluation of the influences of sample preparation and analytical detection methods on the measurement of SP in plasma. The results indicate that sample preparation (peptide extraction versus no extraction) and the choice of analytical method for SP quantitation may yield significantly different values and may contribute to the variability in SP values reported in the literature. These results further emphasize the need for careful consideration in the selection of methods for SP quantitation, as well as caution in the interpretation and comparison of data reported in the literature.

A role for PKC-delta and PI 3-kinase in TNF-alpha-mediated antiapoptotic signaling in the human neutrophil.

The proinflammatory cytokine tumor necrosis factor (TNF)-alpha has been implicated in the attenuation of neutrophil spontaneous apoptosis during sepsis. Antiapoptotic signaling is principally mediated through the p60TNF receptor (p60TNFR). In neutrophils, TNF-alpha is an incomplete secretagogue and requires input from a ligated integrin(s) for neutrophil activation. In adherent neutrophils, TNF-alpha triggers association of both protein kinase C (PKC)-delta and phosphatidylinositol (PI) 3-kinase with the p60TNFR. In this study, a role for PKC-delta and PI 3-kinase in TNF-alpha-mediated antiapoptotic signaling was examined. TNF-alpha inhibited spontaneous apoptosis in fibronectin-adherent neutrophils, and this antiapoptotic signaling was blocked by the PKC-delta inhibitor rottlerin, but not by an inhibitor of Ca(2+)-dependent PKC isotypes, Go-6976. Inhibition of PI 3-kinase by LY-294002 also inhibited TNF-alpha-mediated antiapoptotic signaling. Cycloheximide blocked TNF-alpha-mediated antiapoptotic signaling, suggesting protein synthesis is required. Inhibition of either PKC-delta or PI 3-kinase attenuated TNF-alpha-mediated activation of the antiapoptotic transcription factor NFkappaB. Thus both PKC-delta and PI 3-kinase have essential roles in TNF-alpha-mediated antiapoptotic signaling in adherent neutrophils.

Persistent decreases in blood plasmacytoid dendritic cell number and function despite effective highly active antiretroviral therapy and increased blood myeloid dendritic cells in HIV-infected individuals.

Dendritic cells (DC) have an instrumental role in the activation and function of both innate and adaptive immune responses. In humans, at least two distinct DC subsets have been characterized based on phenotypic markers: the myeloid DC (MDC) and the plasmacytoid DC (PDC). Both subsets are critical producers of cytokines (IL-12 for MDC and type I/II IFNs for PDC) and are functionally different. We show in this study that HIV(+) individuals have a significant decrease in the number of the Lin(-)HLA-DR(+)CD123(+) and BDCA-2(+) PDC compared with uninfected donors (p = 0.0001). HIV(+) individuals also have a sustained impairment in viral-induced IFN-alpha production (p < 0.0001). The decrease of the PDC subsets did not correlate with CD4 count or viral load and was not reversed in subjects under virally suppressive treatment, suggesting an irreversible change after infection. By contrast, the absolute number and median frequency of MDC in HIV-infected individuals were similar to those observed in uninfected controls, while a significant decrease was present in subjects with >5000 HIV-1 copies/ml. The inverse association with viral load of the MDC number, but not of IFN-alpha secretion or the number of PDC, suggests a role for MDC in viral control. Our data suggest that DC subsets are differentially reconstituted during the immune recovery associated with antiviral therapy. The persistent impairment of certain DC subsets may result in a sustained defect in DC-mediated innate immune functions despite an effective treatment regimen.

The effects of avoidance on cytotoxic/suppressor T cells in women with cervical lesions.

The purpose of this study was to examine the relationship between avoidant and intrusive ideation about cancer risk and immune responses among women with mild cervical dysplasia. Participants were 54 women undergoing diagnostic follow-up (i.e. colposcopy) for an abnormal Pap smear test result. Baseline assessments, collected prior to the colposcopy appointment, included demographic and medical history, levels of depression, and the intrusion and avoidance subscales of the Revised Impact of Events Scale. In addition, a sample of blood was obtained at baseline and 6-month follow-up for immune assessments. Hierarchical regression analyses revealed that higher levels of cognitive and behavioral avoidance at baseline predicted a significantly lower percentage of circulating cytotoxic/suppressor T cells (CD3(+)/CD8(+)) at 6-month follow-up, after controlling for baseline levels of cytotoxic/suppressor T cells and potential confounding variables (e.g. age, smoking status). Baseline intrusive ideation was unrelated to changes in percentage of cytotoxic/suppressor T cells. Avoidant ideation, but not intrusive ideation or depression, appears to be associated with alterations in immunologic measures in women with cervical lesions. The findings suggest that it may be important to evaluate the impact of cognitive and behavioral avoidance on progression of precancerous cervical lesions.