Impaired Lymphocyte Profile in Schistosomiasis Patients with Periportal Fibrosis

Luciana Santos Cardoso,Ricardo Riccio Oliveira,Jamille Souza Fernandes,Robson Da Paixão De Souza,Maria Ilma Araujo,Andréia De Souza Rocha Barreto,Edgar M Carvalho

doi:10.1155/2013/710647

Abstract

The Th2 immune response in chronic schistosomiasis is associated with the development of periportal fibrosis. However, little is known about the phenotype and activation status of T cells in the process. Objective. To evaluate the profile of T cells in schistosomiasis patients with periportal fibrosis. Methods. It was a cross-sectional study, conducted in the village of Agua Preta, Bahia, Brazil, which included 37 subjects with periportal fibrosis determined by ultrasound. Peripheral blood mononuclear cells were obtained by the Ficcol-hypaque gradient and the frequency of T cells expressing the surface markers CD28, CD69, CD25, and CTLA-4 was determined by flow cytometry. Results. The frequency of CD4+CD28+ T lymphocytes was higher in individuals with moderate to severe fibrosis compared to patients with incipient fibrosis. We did not observe any significant difference in the frequency of CD4+ T cells expressing CD69 among groups of individuals. There was also no significant difference in the frequency of CD8+ T cells expressing CD28 or CD69 among the studied groups. Individuals with moderate to severe fibrosis presented a lower frequency of CD8+ T cells, CD4+CD25high T cells, and CD4+CTLA-4+ T cells when compared to patients without fibrosis or incipient fibrosis. The frequency of CD4+CD25low cells did not differ between groups. Conclusion. The high frequency of activated T cells coinciding with a low frequency of putative Treg cells may account for the development of periportal fibrosis in human schistosomiasis.

Highlights

Schistosomiasis is a parasitic disease which accounts for the second place in terms of socioeconomic and public health burden in tropical and subtropical areas
While the frequency of CD3+CD4+ T cells was similar among patients with different degrees of periportal fibrosis (Figure 1(b)), a lower frequency of CD8+ T cells was observed in individuals with moderate to severe fibrosis, compared to those without fibrosis (16%; 13%– 29.7%) or with incipient fibrosis (11.6%; 0.8%–21.1%; P < 0.05; Figure 1(c))
We evaluated the frequency of T cells expressing some molecules associated with T cell activation status, such as CD28, CD69, and CTLA-4

Summary

Introduction

Schistosomiasis is a parasitic disease which accounts for the second place in terms of socioeconomic and public health burden in tropical and subtropical areas. It is a chronic and debilitating disease caused by parasites of the genus Schistosoma. Liver pathology results from the host immune response to antigens from the eggs that become trapped in the portal venous system. The granulomas formed around the eggs act as barriers which prevent the dispersion of egg antigens of S. mansoni. About 5% of infected individuals evolve to periportal fibrosis which is associated with the morbidity and mortality described in chronic schistosomiasis [2,3,4]

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Results

Conclusion