Joelma Rodrigues de Souza

Evaluation of an interferon gamma assay in the diagnosis of latent tuberculosis infection in patients with rheumatoid arthritis.

The tuberculin skin test is not an ideal screening test for the patients with rheumatoid arthritis to identify cases of latent tuberculosis infection (LTBI) prior to the start of treatment with anti-TNFs, as it responds inadequately to late hypersensitivity, which is fundamental for producing a response to the inoculated antigen. Assays based on detection of the production of IFNγ in vitro by mononuclear peripheral cells stimulated by specific antigens are more specific than PPD in detecting LTBI. The aim of this study was to evaluate the performance of T-SPOT.TB in diagnosis of LTBI in patients with rheumatoid arthritis, comparing with the PPD. The specificity of the T-SPOT.TB varied from 87 to 90% and the negative-predictive value (NPV) from 94.4 to 100%. It can be concluded that the T-SPOT.TB showed high specificity and NPV, proving the capability of identifying false-negative cases of PPD, raising the level of safety for the use of anti-TNFs.

Cytokine profile associated with chronic and acute human schistosomiasis mansoni.

The production and regulation of interleukin (IL) IL-13, IL-4 and interferon-gamma (IFN-gamma) was evaluated in 43 schistosomiasis patients with different clinical forms. Whole-blood cultures cytokine production in response to soluble egg antigen (SEA), soluble worm adult preparation (SWAP), mitogens, neutralizing antibodies or recombinant IL-13 were measured by ELISA. After SWAP stimulation, chronic patients, particularly hepatointestinals, produced higher levels of IL-4 in comparison with acute patients, suggesting the presence of a type 2 cytokine profile in these patients. Following SEA and SWAP stimulation, hepatosplenic (HS) patients showed increased levels of IFN-gamma when compared with acute patients, indicating that HS disease in humans is associated with a type 1 cytokine response. The mechanisms of immune regulation are apparently different between the clinical stages of the disease, some of which are antigen-specific.

The effect of Zymomonas mobilis culture on experimental Schistosoma mansoni infection

C57Bl/10 male mice infected with Schistosoma mansoni were distributed into mixed, prophylactic and curative groups. A culture of Zymomonas mobilis was orally administered to mice. A 61% protection from the infection was observed in the curative group (p <0.05). Histopathological study of the livers and intestines showed similar results.

Discriminating acute from chronic human schistosomiasis mansoni.

Specific immunoglobulin (IgA, IgG and IgM) responses to different antigen targets (soluble eggs antigen--SEA, soluble worm adult protein--SWAP and keyhole limpet hole--KLH) were measured by enzyme linked immunosorbent assay (ELISA) in patients with acute and chronic schistosomiasis, as well as patients without schistosomiasis. SEA IgA and KLH IgM presented high discriminatory powers to distinguish acute from chronic schistosomiasis, with calculated areas under the curve (AUCs) of 0.88 and 0.82, respectively, obtained from receiver operating characteristic (ROC) curve. On the other hand, these tests, particularly SEA IgA were not useful to distinguish schistosomiasis (including the acute and chronic forms) from individuals without this disease, but infected with other intestinal parasites (Ascaris lumbricoides, Trichuris trichiura and hookworm). By contrast, SWAP IgG and SEA IgG were able to discriminate schistosomiasis patients from healthy individuals and patients infected with other parasites (AUCs of 0.96 and 0.85, respectively). Thus, it is possible to use a combination of serological tests, such as SEA IgA and SWAP IgG, to simultaneously establish the diagnosis of schistosomiasis and discriminate the acute from the chronic forms of the disease.

Resposta atenuada ao PPD no diagnóstico de infecção tuberculosa latente em pacientes com artrite reumatoide

INTRODUCTION: With the introduction of Tumor Necrosis Factor Inhibitors (anti-TNFs) into rheumatological practice, it has become obligatory to identify cases of latent tuberculosis infection (LTBI) prior to the start of treatment, using PPD, chest radiography and clinical history of tuberculosis contact. Patients with Rheumatoid Arthritis (RA) have an abnormality of the cellular immune function, characterized by decreasing responsiveness of peripheral mononuclear cells (T Reg lymphocytes), leading to a loss in delayed hypersensitivity, which is fundamental for the recognition of antigens, such as PPD. OBJECTIVES: The purpose of our study was to evaluate the response to PPD in patients with RA, compared with healthy people, in an area where tuberculosis is endemic, as is the state of Pernambuco. METHODOLOGY: We studied 96 patients, 48 with RA and 48 healthy subjects, most of them females. All patients were given an interdermic injection of 0.1 mL PPD RT-23. The reading of the PPD result was carried out 72 hours after application, by way of palpation of maximum transverse diameter of induration, and the result was expressed in millimeters. RESULTS:In the RA group, the average time of diagnosis was 10.2 years, the average dosage of methotrexate was 15.5 mg / week, the average dosage of prednisone 12.7 mg / day and the average activity of the disease, measured using CDAI, was 30.4. In the healthy subjects group there was a greater number of positive PPD results (33.3%) when compared with the results for the RA group (14.6%), with a statistically significant difference (p = 0.034). CONCLUSION:The performance of PPB in LTBI diagnosis is poor in patients with RA. These results suggest that more careful screening needs to be undertaken before treatment with an anti-TNF drug.

Studies on the production and regulation of interleukin, IL-13, IL-4 and interferon-gamma in human Schistosomiasis mansoni

The production and regulation of interleukin (IL) IL-13, IL-4 and interferon-gamma was evaluated in different clinical forms of human schistosomiasis. The mechanisms of immune regulation are apparently different in the various clinical stages of the disease, some of them being antigen specific.

Prevalência de rotavírus em crianças atendidas na rede pública de saúde do estado de Pernambuco

INTRODUCTION: Rotaviruses are considered important etiological agents of acute gastroenteritis and a common cause of the hospitalization of children aged zero to four years-old. In Brazil, the incidence of rotavirus gastroenteritis in children is 12 to 42% and the distribution of infection is related to seasonality, which apparently occurs in different periods and intensity according to each region. The study investigated group A rotavirus in fecal samples of suspected children attended by the public health system of the State of Pernambuco. METHODS: Diagnosis was achieved by ELISA and the Latex agglutination test. RESULTS: Of the 171 samples studied, 33 (19.3%) presented positivity for Rotavirus A. Among positive samples, 72.7% belonged to male patients and 27.3% to female. Among the positive casuistic, 15.2% were vaccinated. When comparing the results obtained for the ELISA and Latex agglutination tests, 100% agreement between positivity by Latex agglutination and ELISA was verified. CONCLUSIONS: The high incidence of this infection reinforces the need to monitor this virus and define health policies concerning its diagnosis, prophylaxis, improvement in socioeconomic conditions and the refinement of the vaccine.

Preliminary results in the immunodiagnosis of tuberculosis in children based on T cell responses to ESAT-6 and PPD antigens

The aim of this work was to study the difference in interferon gamma (IFN-gamma) production by T lymphocytes after early secretory antigen target 6 (ESAT-6) or purified protein derivate (PPD) stimulation in whole blood culture supernatants from children with suspected tuberculosis (TB) disease (n = 21), latent TB infection (n = 16) and negative controls (NC) (n = 22) from an endemic area in Brazil. The concentration of IFN-gamma (pg/ml) was measured by enzyme linked immunosorbent assay and the differences in the IFN-gamma levels for each group were compared and evaluated using an unpaired Students t-test; p values < 0.05 were considered significant. Measurement of IFN-gamma levels after ESAT-6 stimulation raised the possibility of early diagnosis in the latent TB group (p = 0.0030). Nevertheless, the same group showed similar responses to the NC group (p > 0.05) after PPD stimulation. The IFN-gamma assay using ESAT-6 as an antigenic stimulus has the potential to be used as a tool for the immunodiagnosis of early TB in children.

Treatment of human acute schistosomiasis with oxamniquine induces an increase in interferon-gamma response to Schistosoma mansoni antigens

Patients with acute schistosomiasis were studied before and after oxamniquine treatment. They had been exposed to cercariae 5 to 9 weeks before, and presented compatible clinical manifestations, eosinophilia, and high levels of total IgE. Interferon-gamma (IFN-gamma) and interleukin-4 were measured by ELISA in whole blood samples under soluble egg antigen or soluble adult worm preparation stimulation. After treatment, the reduction of leukocytosis and eosinophilia were not significant, but total IgE levels decreased significantly, in contrast to IFN-gamma levels that were significantly increased. The oxamniquine treatment of acute schistosomiasis patients is followed by an improvement of a Th1 response in vitro. If this response has a protective aspect is unknown, and some investigations need to be realized.

Evaluation of tests based on the antibody response to keyhole limpet haemocyanin and soluble egg antigen to differentiate acute and chronic human schistosomiasis mansoni

Specific IgG and IgM responses to soluble egg antigen (SEA) and keyhole limpet haemocyanin (KLH) were measured by ELISA in patients with acute and chronic schistosomiasis. The tests based upon IgM and IgG antibodies responses to KLH presented the best diagnostic discrimination, and can be used in conjunction with clinical and epidemiological data to the differential diagnosis of acute schistosomiasis.