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Dendritic cells are the antigen presenting cells that process antigens effectively and prime the immune system, a characteristic that have gained them the spotlights in recent years. B cell antigen presentation, although less prominent, deserves equal attention. B cells select antigen experienced CD4 T cells to become memory and initiate an orchestrated genetic program that maintains memory CD4 T cells for life of the individual. Over years of research, we have demonstrated that low levels of antigens captured by B cells during the resolution of an infection render antigen experienced CD4 T cells into a quiescent/resting state. Our studies suggest that in the absence of antigen, the resting state associated with low-energy utilization and proliferation can help memory CD4 T cells to survive nearly throughout the lifetime of mice. In this review we would discuss the primary findings from our lab as well as others that highlight our understanding of B cell antigen presentation and the contributions of the MHC Class II accessory molecules to this outcome. We propose that the quiescence induced by the low levels of antigen presentation might be a mechanism necessary to regulate long-term survival of CD4 memory T cells and to prevent cross-reactivity to autoantigens, hence autoimmunity. [ABSTRACT FROM AUTHOR]

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Exercise training has been shown to reduce symptoms and exacerbations in COPD patients; however, the exercise effect on patients’ immune response is poorly known. We thus verified if an exercise program (EP) impacted on proliferative T cell response of COPD patients. Fourteen non-O2 dependent COPD patients on standard treatment were studied. EP consisted in 24 sessions of aerobic and muscular training. Peripheral blood mononuclear cells were stimulated with the mitogen phytohemagglutinin and antigens from Haemophilus influenzae and cytomegalovirus, and the lymphocyte proliferative response (LPR) was assessed through the expression of Ki67 before and after the EP. The Quality of life [COPD assessment test (CAT)], dyspnea [(modified Medical Research Council scale (mMRC)], and 6-min walk distance were also assessed. The EP program increased significantly the LPR of TCD4+ lymphocytes to phytohemagglutinin and cytomegalovirus and H. influenzae antigens, but with TCD8+ lymphocytes the increase was less marked. Consistent with this, a higher proportion of TCD8+ than TCD4+ cells did not express the costimulatory molecule CD28. The EP also resulted in improvement of the quality of life, dyspnea, and physical capacity. The improvement in TCD4+ cell function may represent an additional mechanism through which the EP results in less exacerbations and hospitalizations. [ABSTRACT FROM AUTHOR]

Atherosclerosis is a chronic inflammatory disease characterized by T lymphocyte infiltration into the atherosclerotic plaque. Assessments of T cell subtypes have demonstrated a predominance of CD4 T helper (Th) cells, implicated Th1 and Th17 immunity in both human and mouse atherogenesis, and provided some evidence suggesting protective roles of Th2 and T regulatory cells. Observations that certain inbred mouse strains have an inherent T helper bias suggest a genetic predisposition toward developing a particular T helper phenotype. This review summarizes our current understanding of mechanisms of antigen processing for major histocompatibility complex molecules, describes the different T helper cell subsets and their roles in atherosclerosis, and discusses mechanisms of genetic predisposition toward Th1/Th2 bias in mice. We also present data from our laboratory demonstrating inherent Th1/Th2 phenotypes in apparently healthy human volunteers that are stable over time and discuss the potential implications for cardiovascular disease. [ABSTRACT FROM AUTHOR]

Objective To study the incidence rates, clinical charateristics of oral hairy leukoplakia (OHL) and its relation to the immune status in a sample of human immunodeficiency virus (HIV) -infected adults in Yunan, China. Methods 1 060 adult patients with HIV from January 2008 to June 2010 were evaluated. The age, gender, education grade, diagnosis time of HIV-infected, route of transmission, xerostomia, oral candidiasis, high active antiretroviral therapy and CD4 lymphocytes counts. The occurrence of OHL was recorded by oral examination. The relationship of CD4 lymphocytes counts and the incidence of OHL were analyzed by statistical methods. Results There were 94 OHL patients in 1 060 HIV patients (8.9%). The average age of the OHL patients was (39.33±10.45) years old. 90% OHL was found on the two lateral aspect of the tongue. The CD4 lymphocytes of 70.2% OHL patients were less than 200 mm"3. Conclusion OHL is a frequent finding in patients with indicates severe immunosuppression and associated with the reduction of CD4 lymphocytes. [ABSTRACT FROM AUTHOR]

The dynamic change of human immunodeficiency virus type-1 (HIV-1) particles that cause AIDS displays considerable variation from patients to patients- It is likely that such variation in HIV-1 pathogenesis is correlated with the genetic architecture of hosts. Traditional genetic analysis of HIV-1 infection is based on various biochemical approaches, but it has been little successful because HIV-1 dynamics, as a complex trait, is under polygenic control and sensitive to environmental changes. Here, we present a novel model for integrating mathematical functions for HIV-1 dynamics that have been well constructed into a multivariate mixture model for genetic mapping. This integrative mapping model on the foundation of linkage disequilibrium (LD)-based haplotype block analysis provides unique power to precisely detect human quantitative trait loci (QTL) determining HIV-1 dynamics and facilitates positional cloning of target QTL, The model allows for a number of hypothesis tests for the effects of the dynamic QTL on the virion clearance rate, the infected cell life-span and the average viral generation time in vivo, all of which provide theoretical principles to guide the development of efficient gene therapy strategies. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the role of anti-retroviral therapy (ART) on the susceptibility of peripheral blood lymphocytes (PBL) from HIV-1-infected individuals to activation-induced apoptosis and in comparison with changes in CD4 lymphocyte counts. Eleven symptomatic HIV+ patients were studied. Ex vivo apoptosis was measured in phytohaemagglutinin (PHA)-stimulated PBL and CD4 subsets by flow cytometry, at baseline and after 1 month (4–6 weeks) and 2/3 months of ART. Six patients had extended studies of the effects of therapy to a maximum of 21 months. Lymphocyte apoptosis was significantly elevated in HIV+ patients at baseline (median 22% compared with 7.5% in HIV- risk-matched controls; P < 0.05). This decreased to control levels on ART (7.4% at 4–6 weeks, P < 0.01, and 6.2% at 8–12 weeks, P < 0.05, compared with baseline). Similar changes occurred in the CD4+ subpopulation. The decrease in apoptosis was maintained for several months, but the effect was rapidly lost if ART was discontinued. CD4 counts showed a reciprocal relationship to changes in apoptosis. The association of changes in apoptosis with those in CD4 counts suggests a link between programmed cell death and lymphocyte depletion. Apoptosis reduced in some individuals without any reduction in viral load, suggesting apoptosis may be influenced by factors in addition to the overall extent of HIV replication. [ABSTRACT FROM AUTHOR]

Objective: To elucidate the relationship between HIV, CD4+ count and pleural TB.Method: In a prospective study, 94 patients presenting at two large Harare hospitals with clinically suspected pleural TB were enrolled over a 10-month period. All underwent standardized evaluation, closed pleural aspiration and biopsy. Patients receiving directly observed anti-TB therapy were followed-up.Results: Pleural TB was diagnosed in 90 individuals (median age 33 years; range 18-65; 64 males); the seroprevalence of HIV was 85%. HIV-positive patients were older than HIV-negative individuals (median age 33 vs 23 years, P = 0.013) and had a significantly lower median CD4+ count (191 vs 1106 x 10(6)/l respectively, P = 0.004). A CD4+ count of <200 x 10(6)/l was associated with a length of illness >30 days (65% vs 37%; P = 0.05), a positive pleural fluid smear (37% vs 0%; P = 0.0006) and a positive pleural biopsy Ziehl-Neelsen stain (35% vs 7%; P = 0.021). However, a relationship between CD4+ count and either pleural granuloma formation or radiological evidence of disseminated disease was not observed.Conclusion: In sub-Saharan Africa, TB pleural effusions have become associated with older age, a chronic onset, and an increased mycobacterial load. These data emphasize the complex relationship between pleural TB, HIV infection and a low CD4+ count. [ABSTRACT FROM AUTHOR]

Non-hodgkin's lymphoma (NHL) is the most common haematological malignancy which is seen in HIV infected patients. Among NHLs, immunoblastic lymphomas are most common and a majority of these are diffuse large B-cell lymphomas. Multiple myeloma is a disease of the elderly. It is extremely rare below 30 years of age. On the other hand, in HIV infected individuals, the average age of presentation with plasma cell disorders is 33 years, which is far younger than the average age of presentation in general population. The incidence of AIDS defining malignancies has declined markedly, whereas non-AIDS defining cancers are being increasingly diagnosed in patients with HIV infection during the HAART-era and they may be the presenting manifestations of AIDS. Multiple myeloma, however, usually is not a first presenting feature of AIDS. The usual clinical presentation of multiple myeloma is bone pain and pallor. Pancytopaenia is a rare presenting feature of multiple myeloma. Here, we are reporting a case of pancytopaenia which occurred in a 28-year-old, newly diagnosed, HIV-1 positive female, who with the help of bone marrow examination and further investigations, was subsequently diagnosed as multiple myeloma. [ABSTRACT FROM AUTHOR]