CONICET | Buscador de Institutos y Recursos Humanos

In Argentina, more than 3 million people suffer from asthma, with numbersrising. When asthma patients acquire viral infections which, in turn, triggerthe asthmatic response, they may develop subsequent bacterial infections,mainly by Streptococcus (S.) pneumoniae. This encapsulated Gram+ bacteriumhas been considered historically a T cell-independent antigen. Nevertheless,several papers describe the role of T cells in the immune response toS. pneumoniae.We evaluated the response to S. pneumoniae and compared itto the response to Mycobacterium (M.) tuberculosis, a different type of bacteriumthat requires a T helper type 1 (Th1) response, in cells from atopic asthmaticchildren, to compare parameters for the same individual underexacerbation and in a stable situation whenever possible.We studied asthmapatients and a control group of age-matched children, evaluating cell populations,activation markers and cytokine production by flow cytometry, andcytokine concentration in serum and cell culture supernatants by enzymelinkedimmunosorbent assay (ELISA). No differences were observed in gd Tcells for the same patient in either situation, and a tendency to lower percentagesof CD4+CD25hi T cells was observed under stability.A significantly lower production of tumour necrosis factor (TNF)-a and asignificantly higher production of interleukin (IL)-5 was observed in asthmapatients compared to healthy individuals, but no differences could beobserved for IL-4, IL-13 or IL-10. A greater early activation response againstM. tuberculosis, compared to S. pneumoniae, was observed in the asthmaticpatients cells. This may contribute to explaining why these patients frequentlyacquire infections caused by the latter bacterium and not the former.

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