CD4+CD25hiFOXP3+ Regulatory T Cells and Cytokine Responses in Human Schistosomiasis before and after Treatment with Praziquantel.

• Published in: PLOS Neglected Tropical Diseases
• Main Authors: Yvonne Schmiedel, Ghyslain Mombo-Ngoma, Lucja A Labuda, Jacqueline J Janse, Brechje de Gier, Ayôla A Adegnika, Saadou Issifou, Peter G Kremsner, Hermelijn H Smits, Maria Yazdanbakhsh
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2015
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Public aspects of medicine; RA1-1270; Arctic; Calmette
• Online Access: https://doi.org/10.1371/journal.pntd.0003995; https://doaj.org/article/afc75643e3364643b29240dfa1944765

BACKGROUND:Chronic schistosomiasis is associated with T cell hypo-responsiveness and immunoregulatory mechanisms, including induction of regulatory T cells (Tregs). However, little is known about Treg functional capacity during human Schistosoma haematobium infection. METHODOLOGY:CD4+CD25hiFOXP3+ cells were characterized by flow cytometry and their function assessed by analysing total and Treg-depleted PBMC responses to schistosomal adult worm antigen (AWA), soluable egg antigen (SEA) and Bacillus Calmette-Guérin (BCG) in S. haematobium-infected Gabonese children before and 6 weeks after anthelmintic treatment. Cytokines responses (IFN-γ, IL-5, IL-10, IL-13, IL-17 and TNF) were integrated using Principal Component Analysis (PCA). Proliferation was measured by CFSE. PRINCIPAL FINDINGS:S. haematobium infection was associated with increased Treg frequencies, which decreased post-treatment. Cytokine responses clustered into two principal components reflecting regulatory and Th2-polarized (PC1) and pro-inflammatory and Th1-polarized (PC2) cytokine responses; both components increased post-treatment. Treg depletion resulted in increased PC1 and PC2 at both time-points. Proliferation on the other hand, showed no significant difference from pre- to post-treatment. Treg depletion resulted mostly in increased proliferative responses at the pre-treatment time-point only. CONCLUSIONS:Schistosoma-associated CD4+CD25hiFOXP3+Tregs exert a suppressive effect on both proliferation and cytokine production. Although Treg frequency decreases after praziquantel treatment, their suppressive capacity remains unaltered when considering cytokine production whereas their influence on proliferation weakens with treatment.