RESUMO
Chagas' disease is caused by infection with Trypanosoma cruzi. Patients in the chronic phase of infection were grouped as belonging to the asymptomatic (or indeterminate), cardiac and cardiac plus digestive forms. Previous studies have described abnormal immune responsiveness by peripheral blood mononuclear cells (PBMC) from chronic chagasic patients. We report significant parasite antigen (T-Ag)-stimulated PBMC proliferative responses to be present in all three groups of patients. Treatment of T-Ag-stimulated cultures with rIL-12 significantly amplifies proliferative responses in all patients' groups, with similar rates of increment. IL-12 enhances T-Ag-specific lymphoproliferation without increasing proliferation of unstimulated PBMC from normal individuals or from patients. Comparatively, treatment with rIL-2 enhances both T-Ag-specific and unstimulated proliferation by PBMC from patients and normals. Thus, IL-12 acts on pre-activated cells while IL-2 also stimulates resting cells. No synergism was obtained by the combined use of IL-12 and IL-2. Therefore IL-12 can act as a more selective amplifier of T. cruzi reactive cells than IL-2. IL-12, by enhancing parasite-antigen specific immunity, could be of potential therapeutic use to control reactivated T. cruzi infections concomitant to AIDS or other situations of immunosuppression.
Assuntos
Antígenos de Protozoários/imunologia , Antígenos de Superfície/imunologia , Doença de Chagas/imunologia , Interleucina-12/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Trypanosoma cruzi/imunologia , Glicoproteínas Variantes de Superfície de Trypanosoma , Animais , Divisão Celular/efeitos dos fármacos , Humanos , Interleucina-2/farmacologia , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/imunologiaRESUMO
The purpose of our study was to carry out a prospective follow-up of 114 newborns at term (including three pairs of twins), regarding clinical manifestations for atopy during the first year of life. Their IgE levels in cord blood samples, at 3, 6, 9 and 12 months of age were measured and the influence of race, sex, breast-feeding, maternal smoking, family income, month of birth, family history and personal manifestations of atopic disease were evaluated. Total serum immunoglobulin E was quantified by microparticle enzyme immuno-assay (MEIA). The study group consisted of 60 (53%) male neonates, 67 (59%) Caucasians and 47 (41%) blacks. In the clinical follow-up, 32 (28.1%) infants developed obvious atopic disease: 29 infants presented recurrent wheezing, two had cow's milk allergy and one had atopic dermatitis. Probable atopic disease developed in 12 (10.5%) infants, whereas 70 (61.4%) infants showed no manifestations. Cord blood IgE levels in infants with obvious atopic disease was higher when compared to those without (p = 0.024), with 70.97% sensitivity and 46.2% specificity. IgE levels were also significantly different up to 12 months in these groups (p = 0.0001), when the sensitivity was 82.1% and the specificity 54.1%. At this age, the IgE levels were higher in infants with obvious atopy than nonatopic disease in relation to male sex (p = 0.015), black race (p = 0.009), breast-feeding for less than 6 months (p = 0.011) and when the family income was less than three times the minimum wage (about US $300) (p = 0.006). There was no association between IgE levels and family history of atopy. We concluded that immune response for atopy was in a large degree influenced by environmental factors and serum IgE at 12 months was a good marker for identifying infants with risk of atopic disease in early life.
Assuntos
Hipersensibilidade Imediata/genética , Recém-Nascido/imunologia , Aleitamento Materno , Estudos de Coortes , Saúde da Família , Feminino , Sangue Fetal/imunologia , Humanos , Hipersensibilidade Imediata/economia , Hipersensibilidade Imediata/imunologia , Hipersensibilidade Imediata/fisiopatologia , Imunoglobulina E/sangue , Lactente , Masculino , Gravidez , Estudos Prospectivos , Grupos Raciais , Fatores Sexuais , Fumar/imunologiaRESUMO
Aqueous-soluble (AS) antigens from larvae of Strongyloides stercoralis, extracted with phosphate-buffered saline, are traditionally used for serodiagnosis of strongyloidiasis. To identify sources of antigens for use in serodiagnosis, residual particulates from parasite larvae after aqueous extraction were solubilized with Tris-buffered 8M urea, yielding a urea-soluble (US) antigen fraction. Both AS and US antigens from S. stercoralis were evaluated by an enzyme-linked immunosorbent assay. No significative differences were observed between AS and US antigens from the parasite regarding specific antigenic activity and cross-reactivity. Immunoassays are highly dependent on the antigen for sensitivity and specificity. Crude extracts from S. stercoralis should be further studied, mainly in relation to antigenic fractions which could provide even more sensitive and specific results. Studies of fractionation of S. stercoralis must take into account the antigen yield of both the crude extract and fractions, since larvae of parasite are normally difficult to obtain. Considering this aspect, the results from this study are very useful, since the extraction with urea substantially increased the amounts of antigenic materials normally obtained with the classical aqueous extraction.
Assuntos
Antígenos de Helmintos , Strongyloides stercoralis/imunologia , Estrongiloidíase/diagnóstico , Animais , Antígenos de Helmintos/isolamento & purificação , Diagnóstico Diferencial , Ensaio de Imunoadsorção Enzimática/métodos , Estudos de Avaliação como Assunto , Humanos , Larva/imunologia , SolubilidadeRESUMO
The relationship between wheezing or asthma and serum immunoglobulin (Ig)E levels in early life is unclear. The aim of this study was to follow-up the IgE immune response in infants that did, or did not, develop recurrent wheezing during their first year of life. One-hundred and two randomised term neonates were included, in which IgE levels were quantified in cord blood samples, at 3, 6, 9 and 12 months of age. Specific IgE levels for food and inhalant allergens and the skin-prick test for inhalant allergens were also assessed at 6 and 12 months. During clinical follow-up, 32 (31%) infants presented with two or more wheezing episodes, while 70 (69%) had no wheezing. Total IgE levels were significantly higher up to 12 months in wheezing infants when compared to nonwheezing group. At 12 months, the specific IgE levels to cow's milk, egg white and mites were higher in infants with recurrent wheezing. There was no influence of family history for atopy on IgE levels. The skin-prick tests were positive in 14% and 23% in wheezing infants at 6 and 12 months, respectively. These results indicate an early allergic sensitisation in wheezing infants, suggesting an altered immunoregulatory T-cell role in immunoglobulin E production.
Assuntos
Imunoglobulina E/sangue , Sons Respiratórios/imunologia , Alérgenos , Ensaio de Imunoadsorção Enzimática , Feminino , Sangue Fetal/imunologia , Seguimentos , Humanos , Hipersensibilidade/sangue , Hipersensibilidade/diagnóstico , Hipersensibilidade/genética , Imunoglobulina A/sangue , Lactente , Recém-Nascido , Testes Intradérmicos , Medições Luminescentes , Masculino , Estudos ProspectivosRESUMO
A retrospective study of laboratory records in a 400-bed university hospital in Campinas city, SP (Southeastern Brazil) suggests that infection by Strongyloides stercoralis is widespread in the region. A prevalence of 10.81% was found in 37,621 stool specimens examined in a two-year period. Parasite-specific IgG antibodies were measured by ELISA in sera from 90 patients with strongyloidiasis. The ELISA detected antibody in 76 (84.44%) patients, indicating that serodiagnostic tests may be helpful in screening patients for strongyloidiasis.