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Volunteers living in an area where schistosomiasis mansoni is endemic were subjected to ultrasound examination and classified into groups according to the levels of fibrosis diagnosed, namely, absence of indications of fibrosis (group 0), incipient fibrosis (group 1), and moderate/severe fibrosis (group 2). Peripheral blood mononuclear cells (PBMC) collected from the volunteers were stimulated with soluble antigens from adult schistosomes or from schistosome eggs, and the production of the cytokines gamma interferon, tumor necrosis factor alpha, transforming growth factor ␤ (TGF-␤), interleukin-4 (IL-4), IL-10, and IL-13 was determined. Potential associations of the level of fibrosis with age, sex, intensity of infection, and cytokine production were investigated between the three groups. Univariate analysis identified associations of age (>50), gender (male), and absence of eggs/g of feces with moderate/severe fibrosis and an association of intensity of infection (>100 eggs) with incipient fibrosis. When cytokine production in PBMC cultures stimulated by soluble egg antigens was categorized as low or high, significant differences in the distribution of IL-13 levels were established between groups 0 and 2. No significant differences were detected between the groups in the cytokines produced by PBMC cultures stimulated with soluble antigens from adult schistosomes. When all variables were tested in multivariate analyses, only IL-13 was strongly associated with fibrosis (odds ratio ‫؍‬ 5.8; 95% confidence interval [CI] ‫؍‬ 1

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Herein we have focused attention on major phenotypic features of peripheral blood eosinophils from chronic Schistosoma mansoni-infected patients. For this purpose, detailed immunophenotypic profiles of a range of cell surface markers were performed, including activation markers (CD23/CD69/CD25/HLA-DR), co-stimulatory molecules (CD28/CD80/CD86), chemokine receptors (CXCR1/CXCR2/CCR3/CCR5) besides L-selectin-CD62L and adhesion molecules (CD18/CD54). Our major findings pointed out increased frequency of CD23 + -cells, besides decreased percentages of CD69 + -eosinophils, suggesting a chronic activation status with low frequency of early activated eosinophils in chronic S. mansoni-infected patients (INT) in comparison to non-infected individuals (NI). Moreover, a dichotomic expression of beta-chemokine receptors was observed during human schistosomiasis mansoni with higher CCR5 and lower levels of CCR3 observed between groups. Enhanced expression of co-stimulatory receptors (CD28/CD86) and adhesion molecules (CD54/CD18), besides striking lower frequency of L-selectin + were reported for eosinophils from INT group as compared to NI. Interestingly, the frequency of CD62L + -eosinophils and a range of cell activation related molecules pointed out an opposite pattern of association in NI and INT, where only INT patients that display lower frequency of CD62L + -eosinophils (first CD62L tertile) kept the unusual relationship between the expression of L-selectin and the CD23 activation marker. These findings suggest that distinct dynamic of activation markers expressed by eosinophils may occur during chronic S. mansoni infection.Key words: schistosomiasis -eosinophils -activation markers -L-selectin Eosinophils have been shown to play a major role in the immune response to helminthic infections (Butterworth et al. 1979, Hamann et al. 1987. In this context, transendothelial migration is essential for eosinophil recruitment from blood vessels into inflammatory tissues. At the inflammatory site, further interaction with invading parasites occurs via adherence with subsequent larval damage mediated by release of eosinophil toxic granular effector molecules, proinflammatory lipids, and cytokines (Greene et al. 1981, Medina-De la Garza et al. 1990, Strote et al. 1990, Brattig et al. 1991, Wildenburg et al. 1994. The prerequisite for adherence of effector eosinophils to parasite's larval stages is their sequential activation and chemotactic attraction that favor the eosinophils tethering. The migration of mature activated eosinophils from circulatory pools into the inflammatory foci depends on specific upregulation of adhesion molecules and chemokine receptors, which direct transmigration through a positive chemotactic gradient. This phenomenon seems to represent the key element for eosinophils recruitment that lead to accumulation of these proinflammatory cells that surround the parasite in its microenvironment (Pearlman 1997, Tachimoto et al. 2000.The profile of cell surface molecules expression on mature eosinophils resembles...