The regulation of normal and allergic immune responses to airborne allergens in the mucosa is still poorly understood, and the mechanism of specific immunotherapy (SIT) in normalizing the allergic response to such allergens is currently not clear. Accordingly, we have investigated the immunoregulatory mechanism of both normal and allergic responses to the major house-dust mite (HDM) and birch pollen allergens -Dermatophagoides pteroynyssinus (Der p)1 and Bet v 1, respectively -as well as the immunologic basis of SIT to HDM in rhinitis and asthma patients. In normal immunity to HDM and birch pollen, an allergen-specific peripheral T cell suppression to Der p 1 and Bet v 1 was observed. The deviated immune response was characterized by suppressed proliferative T cell and Th1 (IFN-+ ) and Th2 (IL-5, IL-13) cytokine responses, and increased IL-10 and TGF-g secretion by allergen-specific T cells. Neutralization of cytokine activity showed that T cell suppression was induced by IL-10 and TGF-g during SIT and in normal immunity to the mucosal allergens. In addition, SIT induced an antigen-specific suppressive activity in CD4 + CD25 + T cells of allergic individuals.Together, these results demonstrate a deviation towards a regulatory/suppressor T cell response during SIT and in normal immunity as a key event for the healthy immune response to mucosal antigens.

The diagnostic value of procalcitonin, C-reactive protein, tumor necrosis factor-alpha, and interleukin-10 levels in differentiating sepsis from severe sepsis and the prognostic value of these levels in predicting outcome were evaluated and compared in patients with community-acquired sepsis, severe sepsis, and septic shock in the first 72 h of admission to the hospital. Thirty-nine patients were included in the study. The severe sepsis and septic shock cases were combined in a single "severe sepsis" group, and all comparisons were made between the sepsis (n=21 patients) and the severe sepsis (n=18 patients) groups. Procalcitonin levels in the severe sepsis group were found to be significantly higher at all times of measurements within the first 72 h and were significantly higher at the 72nd hour in patients who died. Procalcitonin levels that remain elevated at the 72nd hour indicated a poor prognosis. C-reactive protein levels were not significantly different between the groups, nor were they indicative of prognosis. No significant differences in the levels of tumor necrosis factor-alpha were found between the sepsis and severe sepsis groups; however, levels were higher at the early stages (at admission and the 24th hour) in patients who died. Interleukin-10 levels were also higher in the severe sepsis group and significantly higher at all times of measurement in patients who died. When the diagnostic and prognostic values at admission were evaluated, procalcitonin and interleukin-10 levels were useful in discriminating between sepsis and severe sepsis, whereas tumor necrosis factor-alpha and interleukin-10 levels were useful in predicting which cases were likely to have a fatal outcome.

Allergen-specific immunotherapy represents one of the few curative approaches toward type I allergy. Up to 25% of allergic patients are sensitized against the major birch pollen allergen, Bet v 1. By genetic engineering we produced two recombinant (r) Bet v 1 fragments comprising aa 1–74 and aa 75–160 of Bet v 1, which, due to a loss of their native-like fold, failed to bind IgE Abs and had reduced allergenic activity. Here we show that both fragments covering the full Bet v 1 sequence induced human lymphoproliferative responses similar to rBet v 1 wild type. The C-terminal rBet v 1 fragment induced higher lymphoproliferative responses than the N-terminal fragment and represented a Th1-stimulating segment with high IFN-γ production, whereas the N-terminal fragment induced higher IL-4, IL-5, and IL-13 secretion. Immunization of mice and rabbits with rBet v 1 fragments induced IgG Abs, which cross-reacted with complete Bet v 1 and Bet v 1-related plant allergens and strongly inhibited the IgE binding of allergic patients to these allergens. Thus, our results demonstrate that hypoallergenic T cell epitope-containing rBet v 1 fragments, despite lacking IgE epitopes, can induce Abs in vivo that prevent the IgE binding of allergic patients to the wild-type allergen. The overall demonstration of the immunogenic features of the hypoallergenic rBet v 1 fragments will now enable clinical studies for safer and more efficient specific immunotherapy.

No abstract

No abstract