Clinical and immunologic evaluation of 31 patients with acute schistosomiasis mansoni

Thirty-one patients with acute schistosomiasis were evaluated clinically and immunologically. Cytokine levels were determined in peripheral blood mononuclear cell (PBMC) supernatants. Levels of total and antigen-specific IgE, tumor necrosis factor (TNF)-alpha, and immune complexes were measured in serum samples. Clinical findings included general symptoms, liver damage, pulmonary involvement, and pericarditis. All patients had eosinophilia. Immune complexes were detected in 55% of the patients (mean +/- SD, 7.8 +/- 7.6 mug Eq/mL) and were associated with cough, dyspnea, and abnormal chest radiographic findings. Levels (mean +/- SD) of TNF-alpha (1349.3 +/- 767.6 pg/mL), interleukin (IL)-1 (2683 +/- 1270 mug/mL), and IL-6 (382 +/- 52.3 pg/mL) were elevated in PBMC. Serum TNF-alpha levels were elevated in 87% of the patients and were associated with abdominal pain. Higher interferon-gamma levels were detected in PBMC of patients with acute disease than in those of patients with chronic schistosomiasis; IL-5 levels were higher in those with chronic disease. Low IL-5 levels were associated with weight loss. Proinflammatory cytokines and immune complexes with low Th2 responses might explain the immunopathogenesis of acute schistosomiasis

O mito da doença rara The rare disease myth

Demonstra-se que estudos caso-controle podem estimar sem viés os parâmetros risco relativo e fração atribuível, sem que a doença estudada seja rara. Argumenta-se que a pressuposição de raridade da doença para que as estimativas de odds ratio obtidas em estudos caso-controles se aproximem da medida de risco relativo é um mito ainda hoje difundido, que teve suas origens nos primeiros trabalhos, estabelecendo e consolidando o método caso-controle, em meados do século XX.<br>This paper shows that case-control studies can produce unbiased estimates of relative risk and attributable fraction without assuming that the studied disease is rare. It also discusses the still current myth that it is necessary to assume that a disease is rare in order to assure that odds ratio estimates are closer to relative risk measures in case control studies, showing that it comes from the beginning of the methodological development of case-control studies, in the mid 20th Century