RSV respiratory infection in children under 5 y.o.--dynamics of the immune response Th1/Th2 and IgE.

Introduction: The imbalance of Th1/Th2 cytokine concentrations and increased level of IgE might be useful tool for prediction of severity of RSV infection among young children and possibility of sequels. The ratio of cytokines Th1/Th2 varied during the disease. THE AIM of our studies was the assessment of immunological response by dynamics of Th1 and Th2 cytokines and IgE in RSV infections.

Material And Methods: Study was done on sera collected from 36 young children hospitalized because of RSV infection and from 16 children with other respiratory tract infection (HMPV, EV, HPIV1-3). Assaying of the serum levels of cytokine Th1 (IL-2, IFN-g, TNF), Th2 (IL-4, IL-6, IL-10) and concentration of IgE has been done. Paired sera (48 patients) were collected in the interval 4-14 days. Reference group consist of 18 children (< 6 months of life) hospitalised because other than respiratory diseases with negative results for viruses tested by PCR.

Results: Among children with respiratory infection the Th1/Th2 ratio was shifted towards Th2, level of IgE increased in comparison to the reference group. Changes in concentration of IL-6, IFN-g, IL-10 were related to RSV infection, mainly bronchitis and bronchiolitis, while the dynamic of TNF concentration was independent on aetiological agent. It was found that the risk factors (prematurity, artificial nutrition) correlated with RSV bronchitis and the levels of cytokines and IgE. Increased level of IL-6 and IL-10 were shown in prematures, and increased concentration of IgE--among artificial nourished children. The time of serum collection affected the level of cytokines and IgE and the effect was depended on the aetiological agent. In RSV infections was observed significant decrease with time of IL-6, IL-10 and IFN-gamma but not IgE (still significantly higher than in the reference group). While the significant decrease of IgE was determined only in other than RSV infections.

Conclusions: Determined level of cytokines and IgE varied depending on the time of serum collection. Observed dynamics in paired sera and IgE might have prognostic value in disease and sequels of RSV infections. Prevention RSV infection in premature infants should be done in any possible way. Breastfeeding is one of the critical elements of prevention of RSV infection.