Social and immunological differences among uninfected Brazilians exposed or unexposed to human immunodeficiency virus-infected partners

Understanding the social conditions and immunological characteristics that allow some human immunodeficiency virus (HIV)-exposed patients to remain uninfected represents an on-going challenge. In this study, the socio-demographic and sexual behaviour characteristics and immune activation profiles of uninfected individuals exposed to HIV-infected partners were investigated. A confidential and detailed questionnaire was administered and venous blood was tested using HIV-1/enzyme immunoassays, plasma HIV-1 RNA levels/bDNA and immunophenotyping/flow cytometry to determine the frequencies of CD4 and CD8 T cells expressing activation markers. The data analysis showed significant differences (p < 0.05) for immune parameters in individuals who were uninfected, albeit exposed to HIV-infected partners, compared with unexposed individuals. In particular, the exposed, uninfected individuals had a higher frequency (median, minimum-maximum) of CD4+HLA-DR+ (4.2, 1.8-6.1), CD8+HLA-DR+ (4.6, 0.9-13.7), CD4+CD45RO+ (27.5, 14.2-46.6), CD4+CD45RO+CD62L+ (46.7, 33.9-67.1), CD8+CD45RA+HLA-DR+ (12.1, 3.4-35.8) and CD8+CD45RO+HLA-DR+ (9.0, 3.2-14.8) cells, a decreased percentage of CD8+CD28+ cells (11.7, 4.5-24.0) and a lower cell-surface expression of Fcγ-R/CD16 on monocytes (56.5, 22.0-130.0). The plasma HIV-1 RNA levels demonstrated detectable RNA virus loads in 57% of the HIV-1+ female partners. These findings demonstrate an activation profile in both CD4 and CD8 peripheral T cells from HIV-1 exposed seronegative individuals of serodiscordant couples from a referral centre in Belo Horizonte, state of Minas Gerais.

Asma: a arte do encontro / Asthma: the art of meeting

A asma é um importante problema de Saúde Pública. Estima-se que ela comprometa cerca de 300 milhões de pessoas e mate 250 mil a cada ano, em todo o mundo. Trata-se de uma alteração inflamatória crônica das vias aéreas, cujas principais características incluem, também, grau variável de obstrução ao fluxo aéreo e hiper-responsividade brônquica. O tratamento é baseado em fármacos anti-inflamatórios e broncodilatadores. Para pacientes que permanecem sintomáticos vêm sendo desenvolvidas novas terapias, desenhadas para atingir alvos-chaves na patogenia.

Asthma is a serious health problem throughout the world. It is estimated that 300 million people are affected and 250 thousands are killed by asthma worldwide. Asthma is a multifactorial chronic inflammatory disorder of the airway in which the chief features include a variable degree of airflow obstruction and bronchial hyper-responsiveness, in addition to the underlying chronic airway inflammation. Asthma's treatment is based on anti-inflammatory and bronchodilator drugs. For patients who remain symptomatic new therapies tailored to target key pathways in asthma pathology are being developed.

Tolerancia inmune y trasplante hepático: introducción para clínicos / Immune tolerance and liver transplant: introduction for clinicians

Immunologic tolerance is the absence of immune response to an allograft, which is specific to graft and, therefore, implies an appropriate immune response to a third party. In clinical practice, a related concept is more frequently used: operational tolerance. Although its frequency is unknown in most of solid organ transplants it is present in the 20 percent of hepatic receptors. This means that tolerant receptors are able to maintain a normal graft function in complete absence of immunosuppressive drugs, avoiding the frequent –and sometimes severe– adverse effects related to its use. In this paper we aim to present physicians who are familiar to liver transplantation to basic concepts related to immune tolerance and operational tolerance in humans.

La tolerancia inmune es la ausencia de una respuesta efectora dirigida al injerto, la cual es específica y, por lo tanto, implica una apropiada respuesta inmune a una tercera parte. En la práctica clínica, un concepto relacionado, es frecuentemente utilizado: la tolerancia operacional. Su frecuencia es desconocida en el trasplante de la mayor parte de órganos sólidos, pero se estima que se desarrolla en el 20 por ciento de los receptores hepáticos. Estos receptores son capaces de mantener una función normal del injerto en ausencia completa e indefinida de inmunosupresores, lo cual les permite evitar los frecuentes y algunas veces graves efectos adversos relacionados con el uso de inmunosupresores. Este artículo pretende introducir a los médicos dedicados al trasplante hepático, a los conceptos básicos relacionados con la tolerancia inmune y la tolerancia operacional en humanos.

Comparative Quantitative Analysis of Cluster of Differentiation 45 Antigen Expression on Lymphocyte Subsets / 대한진단검사의학회지

BACKGROUND: Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT. METHODS: Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA). RESULTS: Among the lymphocyte subsets, the expression of CD45 was the highest (725,368+/-42,763) on natural killer T (NKT) cells, 674,030+/-48,187 on cytotoxic/suppressor T cells, 588,750+/-48,090 on natural killer (NK) cells, 580,211+/-29,168 on helper T (Th) cells, and 499,436+/-21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells. CONCLUSIONS: NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.

Comparative Quantitative Analysis of Cluster of Differentiation 45 Antigen Expression on Lymphocyte Subsets / 대한진단검사의학회지

BACKGROUND: Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT. METHODS: Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA). RESULTS: Among the lymphocyte subsets, the expression of CD45 was the highest (725,368+/-42,763) on natural killer T (NKT) cells, 674,030+/-48,187 on cytotoxic/suppressor T cells, 588,750+/-48,090 on natural killer (NK) cells, 580,211+/-29,168 on helper T (Th) cells, and 499,436+/-21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells. CONCLUSIONS: NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.

Role of IL-1alpha in Cisplatin-Induced Acute Renal Failure in Mice

BACKGROUND/AIMS: For unknown reasons, caspase-1 -/- mice, protected against cisplatin-induced acute renal failure (ARF), are deficient in interleukin (IL)-1alpha. We thus asked whether IL-1alpha deficiency underlies the mechanism of protection against cisplatin-induced ARF in these mice. METHODS: Cisplatin (30 mg/kg) was injected intraperitoneally into wild-type C57BL/6 mice to produce a cisplatin-induced model of ARF. IL-1alpha was measured in control vehicle- and cisplatin-treated wild-type animals. We also examined whether IL-1alpha -/- mice were similarly protected against cisplatin-induced ARF. Additionally, infiltration of CD11b- and CD49b-positive cells, as markers of macrophages, natural killer, and natural killer T cells (pan-NK cells), was investigated in wild-type and IL-1alpha -/- mice. RESULTS: Compared with vehicle-treated mice, renal IL-1alpha increased in cisplatin-treated wild-type mice beginning on day 1. IL-1alpha -/- mice were shown to be protected against cisplatin-induced ARF. No significant difference in the infiltration of neutrophils or CD11b- and CD49b-positive cells were observed between wild-type and IL-1alpha -/- mice. CONCLUSIONS: Mice deficient in IL-1alpha are protected against cisplatin-induced ARF. The lack of IL-1alpha may explain, at least in part, the protection against cisplatin-induced ARF observed in caspase-1 -/- mice. Investigation of the protective mechanism (s) in IL-1alpha -/- mice in cisplatin-induced ARF merits further study.

The requirement of natural killer T-cells in tolerogenic APCs-mediated suppression of collagen-induced arthritis

TGF-beta-induced tolerogenic-antigen presenting cells (Tol-APCs) could induce suppression of autoimmune diseases such as collagen-induced arthritis (CIA) and allergic asthma. In contrast, many studies have shown that NKT cells are involved in the pathogenesis of Th1-mediated autoimmune joint inflammation and Th2-mediated allergic pulmonary inflammation. In this study, we investigated the effect of CD1d-restricted NKT cells in the Tol-APCs-mediated suppression of autoimmune disease using a murine CIA model. When CIA-induced mice were treated with Tol-APCs obtained from CD1d+/- or CD1d-/- mice, unlike CD1d+/- APCs, CD1d-/- Tol-APCs failed to suppress CIA. More specifically, CD1d-/- Tol-APCs failed to suppress the production of inflammatory cytokines and the induction of Th2 responses by antigen-specific CD4 T cells both in vitro and in vivo. Our results demonstrate that the presence of CD1d-restricted NKT cells is critical for the induction of Tol-APCs-mediated suppression of CIA.

The presence of CD8+ invariant NKT cells in mice

Invariant natural killer T (iNKT) cells develop in the thymus upon recognition of CD1d expressed on developing thymocytes. Although CD4 and CD8 coreceptors are not directly involved in the interaction between CD1d and the T cell receptors (TCRs) of iNKT cells, a conspicuous lack of CD8+ iNKT cells in mice raised the question of whether CD8+ iNKT cells are excluded due to negative selection during their thymic development, or if there is no lineage commitment for the development of murine CD8+ iNKT cells. To address this question, we analyzed iNKT cell-specific TCR Valpha14+ transgenic mice, where the Valpha14 transgene forces the generation of iNKT cells. This allows detailed study of the iNKT cell repertoire. We were able to identify CD8+ iNKT cells which respond to the NKT cell-specific glycolipid ligand alpha-galactosylceramide. Unlike conventional iNKT cells, CD8+ iNKT cells produce predominantly IFN-gamma but not IL-4 upon antigen stimulation. We also confirmed the presence of CD8+ iNKT cells in wild type mice. Our results suggest that CD8+ NKT cells do exist in mice, although their population size is quite small. Their Th1-skewed phenotype might explain why the population size of this subtype needs to be controlled tightly.

Intracellular Bacterial Infection and Invariant NKT Cells

The invariant (i) natural killer (NK)T cells represent a unique subset of T lymphocytes which express the V alpha14 chain of the T cell receptor (TCR), that recognizes glycolipid antigens presented by the nonpolymorphic major histocompatibility complex (MHC) class I-like antigen presentation molecule CD1d, and they participate in protection against some microbial pathogens. Although iNKT cells have originally been regarded as T cells co-expressing NKR-P1B/C (NK1.1: CD 161), they do not seem to consistently express this marker, since NK1.1 surface expression on iNKT cells undergoes dramatic changes following facultative intracellular bacterial infection, which is correlated with functional changes of this cell population. Accumulating evidence suggests that NK1.1 allows recognition of "missing-self", thus controling activation/inhibition of NK1.1-expressing cells. Therefore, it is tempting to suggest that iNKT cells participate in the regulation of host immune responses during facultative intracellular bacterial infection by controlling NK1.1 surface expression. These findings shed light not only on the unique role of iNKT cells in microbial infection, but also provide evidence for new aspects of the NK1.1 as a regulatory molecule on these cells.