Maria da Gloria Bonecini-Almeida

Genetic polymorphisms in vitamin D receptor, vitamin D-binding protein, Toll-like receptor 2, nitric oxide synthase 2, and interferon-gamma genes and its association with susceptibility to tuberculosis.

Mycobacterium tuberculosis kills more people than any other single pathogen, with an estimated one-third of the worlds population being infected. Among those infected, only 10% will develop the disease. There are several demonstrations that susceptibility to tuberculosis is linked to host genetic factors in twins, family and associated-based case control studies. In the past years, there has been dramatic improvement in our understanding of the role of innate and adaptive immunity in the human host defense to tuberculosis. To date, attention has been paid to the role of genetic host and parasitic factors in tuberculosis pathogenesis mainly regarding innate and adaptive immune responses and their complex interactions. Many studies have focused on the candidate genes for tuberculosis susceptibility ranging from those expressed in several cells from the innate or adaptive immune system such as Toll-like receptors, cytokines (TNF-alpha, TGF-beta, IFN-gamma, IL-1b, IL-1RA, IL-12, IL-10), nitric oxide synthase and vitamin D, both nuclear receptors and their carrier, the vitamin D-binding protein (VDBP). The identification of possible genes that can promote resistance or susceptibility to tuberculosis could be the first step to understanding disease pathogenesis and can help to identify new tools for treatment and vaccine development. Thus, in this mini-review, we summarize the current state of investigation on some of the genetic determinants, such as the candidate polymorphisms of vitamin D, VDBP, Toll-like receptor, nitric oxide synthase 2 and interferon-gamma genes, to generate resistance or susceptibility to M. tuberculosis infection.

The IFN-³+874T/A gene polymorphism is associated with retinochoroiditis toxoplasmosis susceptibility

Toxoplasmosis is a worldwide zoonosis that generally produces an asymptomatic infection. In some cases, however, toxoplasmosis infection can lead to ocular damage. The immune system has a crucial role in both the course of the infection and in the evolution of toxoplasmosis disease. In particular, IFN-gamma plays an important role in resistance to toxoplasmosis. Polymorphisms in genes encoding cytokines have been shown to have an association with susceptibility to parasitic diseases. The aim of this work was to analyse the occurrence of polymorphisms in the gene encoding IFN-gamma (+874T/A) among Toxoplasma gondii seropositive individuals, including those with ocular lesions caused by the parasite, from a rural population of Santa Rita de Cássia, Barra Mansa, state of Rio de Janeiro, Brazil. Further, we verified which of these polymorphisms could be related to susceptibility to the development of ocular toxoplasmosis. This study included 34 individuals with ocular toxoplasmosis (ocular group) and 134 without ocular lesions (control group). The differences between A and T allele distributions were not statistically significant between the two groups. However, we observed that a higher frequency of individuals from the ocular group possessed the A/A genotype, when compared with the control group, suggesting that homozygocity for the A allele could enhance susceptibility to ocular toxoplasmosis in T. gondii infection.

Effects of human papillomavirus-associated cells on human immunodeficiency virus gene expression.

Objective To examine the effects of soluble factors secreted by human papillomavirus (HPV)-associated cells on human immunodeficiency virus (HIV) expression. Methods Supernatants collected from cultured cervical biopsies and cervical cancer cell lines, and HPV-immortalized and normal keratinocytes were tested for the ability to induce HIV p24 production in two cell lines that contained latent HIV (the U1 monocytic line and the ACH-2 T cell line). Levels of HIV p24 were measured by enzyme-linked immunosorbent assay (ELISA). Culture supernatants were also assayed for the inflammatory cytokines interleukin 6, tumor necrosis factor, and interleukin 1β by ELISA. Results Supernatants from all epithelial cells tested upregulated HIV p24 expression in the U1 line but not in the ACH-2 cells. Only differentiated normal keratinocytes induced p24 production by ACH-2 cells. Neutralization of the cytokines, particularly interleukin 6, partially reduced the level of HIV-inducing activity in the culture supernatants. Additionally, cervical biopsies from HIV-infected women cultured in vitro also were able to induce HIV in U1 cells but not ACH-2 cells. Conclusions Our results suggest that HPV infection of the cervix might influence HIV pathogenesis by inducing the production of immune and inflammatory factors that enhance HIV expression.

Immune response in cervical dysplasia induced by human papillomavirus: the influence of human immunodeficiency virus-1 co-infection - review

Human immunodeficiency virus (HIV-1) has become an important risk factor for human papillomavirus (HPV) infection and the development of HPV associated lesions in the female genital tract. HIV-1 may also increase the oncogenicity of high risk HPV types and the activation of low risk types. The Center for Disease Control and Prevention declared invasive cervical cancer an acquired immunodeficiency virus (AIDS) defining illness in HIV positive women. Furthermore, cervical cancer happens to be the second most common female cancer worldwide. The hosts local immune response plays a critical factor in controlling these conditions, as well as in changes in the number of professional antigen-presenting cells, cytokine, and MHC molecules expression. Also, the production of cytokines may determine which arm of the immune response will be stimulated and may influence the magnitude of immune protection. Although there are many studies describing the inflammatory response in HPV infection, few data are available to demonstrate the influence of the HIV infection and several questions regarding the cervical immune response are still unknown. In this review we present a brief account of the current understanding of HIV/HPV co-infection, emphasizing cervical immune response.

No association of IFNG+874T/A SNP and NOS2A-954G/C SNP variants with nitric oxide radical serum levels or susceptibility to tuberculosis in a Brazilian population subset

Tuberculosis (TB) is one of the most common infectious diseases in the world. Mycobacterium tuberculosis infection leads to pulmonary active disease in approximately 5–10% of exposed individuals. Both bacteria- and host-related characteristics influence latent infection and disease. Host genetic predisposition to develop TB may involve multiple genes and their polymorphisms. It was reported previously that interferon gamma (IFN-γ) and nitric oxide synthase 2 (NOS2) are expressed on alveolar macrophages from TB patients and are responsible for bacilli control; thus, we aimed this study at genotyping single nucleotide polymorphisms IFNG+874T/A SNP and NOS2A-954G/C SNP to estimate their role on TB susceptibility and determine whether these polymorphisms influence serum nitrite and NOx − production. This case-control study enrolled 172 TB patients and 179 healthy controls. Neither polymorphism was associated with susceptibility to TB. NOS2A-954G/C SNP was not associated with serum levels of nitrite and NOx −. These results indicate that variants of IFNG+874T/A SNP and NOS2A-954G/C SNP do not influence TB susceptibility or the secretion of nitric oxide radicals in the study population.

IMMUNE RESPONSE DURING HIV AND TUBERCULOSIS CO-INFECTION

Laboratorio de AIDS e Imunologia Molecular,Departamento de Imunologia, Instituto Oswaldo Cruz,Av. Brasil 4365, 21045-900 Rio de Janeiro, RJ, Brasil*Laboratorio Multidisciplinar de Pesquisa **Servicode Pneumologia, Hospital Universitario ClementinoFraga Filho, Universidade Federal do Rio de Janeiro,RJ, Brasil ***Beatrice and Samuel A Seaver Labora-tory, Division of Hematology-Oncology ****Divisionof International Medicine and Infectious Diseases,Department of Medicine, Cornell University MedicalCollege, New York, NY, USAKey words: tuberculosis - HIV - macrophage -cytokines and cell activation

Genetic polymorphism for IFNγ +874T/A in patients with acute toxoplasmosis.

INTRODUCTION A single nucleotide polymorphism (SNP) in the gene encoding gamma interferon influences its production and is associated with severity of infectious diseases. This study aimed to evaluate the association of IFNγ+874T/A SNP with duration of disease, morbidity, and development of retinochoroiditis in acute toxoplasmosis. METHODS A case-control study was conducted among 30 patients and 90 controls. RESULTS Although statistical associations were not confirmed, A-allele was more common among retinochoroiditis cases and prolonged illness, while T-allele was more frequent in severe disease. CONCLUSIONS Despite few cases, the results could indicate a relation between IFNγ+874T/A single nucleotide polymorphism and clinical manifestations of toxoplasmosis.

Balance of apoptotic and anti-apoptotic marker and perforin granule release in squamous intraepithelial lesions. HIV infection leads to a decrease in perforin degranulation

Cell-mediated cytotoxicity plays an important role in the regulation to HPV-associated cervical intraepithelial neoplasia. HIV co-infection is related to poorer prognosis and more rapid clinical progression to cancer. We evaluated the presence of cervical inflammatory cells, apoptotic (Bax, Bcl-2, FasL, NOS2, perforin) markers and the degranulating expressing cell marker (CD107a) in low and high squamous intraepithelial lesions (LSIL and HSIL, respectively) from HIV-negative and -positive women. Higher percentage of cervical CD4(+), CD8(+) T cells and macrophage were observed in LSIL and HSIL groups when compared with control, especially in epithelium and basal layer of epithelium. However, progression from LSIL to HSIL did not change the frequency of inflammatory cells. HIV-infection lead to a reduction on cervical CD4(+) T cell infiltration and an increased CD8(+) T cell distribution in LSIL groups. A balance between pro- and anti-apoptotic protein expressions was verified. Bax-expressing cells were present in all groups and were rarely expressed in keratinocytes in the epithelium in LSIL and control groups, but notably decreased in HSIL group. However, its frequency was enhanced in the basal layer of the epithelium meanly in LSIL group. Bcl2-expressing cells in the epithelium and the stroma were enhanced in HSIL group when compared with LSIL group. HIV-infection did not interfere in both expressions NOS2 expression was located on keratinocytes in both LSIL and HSIL groups when compared with control group. There were few FasL cervical expressing cells in all groups. Indeed, perforin was identified in few cervical cells. However, CD107a, a surface marker for cellular degranulation was significantly higher in epithelium, basal layer of epithelium and stroma in LSIL and HSIL, respectively, when compared with control group. These results support that HIV infection may induce reduction on inflammatory cervical cell degranulation corroborating to carcinogenesis process. This is the first description on the role of HIV in downregulation of perforin degranulation in the cervical lesions and it might be related to carcinogenesis.

Tuberculin skin testing in HIV-infected patients in Campo Grande, Mato Grosso do Sul State, Brazil

A cross-sectional study on HIV/AIDS was carried out in 108 outpatients from the university hospital of the Federal University of Mato Grosso do Sul, Campo Grande, Brazil, from July to December 2008, to investigate latent tuberculosis infection using the tuberculin skin test (TST). The prevalence of positive results was 13.9%. The CD4+ T cell count (p = 0.091) and the diagnosis time (p = 0.010) were statistically significant when compared with TST positivity. In the cohort of HIV/AIDS patients who had latent tuberculosis infection, the median diagnosis time was eight years. Undetectable viral load presented significant association (p = 0.046) with tuberculosis infection. The fact that numerous individuals with HIV/AIDS infection presented a negative reaction to the tuberculin skin test is probably related to alterations in the cellular immune response induced by HIV infection. The tuberculin test is a useful tool for the detection of latent tuberculosis infection and should be performed in all HIV/AIDS individuals at the time of the diagnosis and on a yearly basis, if negative. Both the early identification of the tuberculosis infection by the tuberculin skin test at the moment of immunological restoration and chemoprophylaxis in infected individuals are mechanisms to control HIV/AIDS and tuberculosis coinfection.

Flow cytometry as a tool to identify Mycobacterium tuberculosis interaction with the immune system and drug susceptibility

Flow cytometric analysis is a useful and widely employed tool to identify immunological alterations caused by different microorganisms, including Mycobacterium tuberculosis. However, this tool can be used for several others analysis. We will discuss some applications for flow cytometry to the study of M. tuberculosis, mainly on cell surface antigens, mycobacterial secreted proteins, their interaction with the immune system using inflammatory cells recovered from peripheral blood, alveolar and pleura spaces and the influence of M. tuberculosis on apoptosis, and finally the rapid determination of drug susceptibility. All of these examples highlight the usefulness of flow cytometry in the study of M. tuberculosis infection.