Recent studies have shown that human basophils, like mast cells, generate interleukin (IL)-4 following immunological activation and may thus participate in late-phase allergic and inflammatory processes. Here, we report the capacity of human basophils to release IL-13 within 24 h following stimulation with anti-IgE. Additionally, in 14 out of 31 experiments, we observed that basophils rapidly release performed IL-4 within 5-10 min, as well as newly generated IL-4, which was released 4 h following stimulation of the cells with anti-IgE. In contrast to the biphasic release of IL-4 from the cells, no preformed IL-13 was detected at earlier times (5-30 min). Preformed IL-4 and IL-4 and IL-13 generated de novo were also released after stimulation of the cells with IL-3; an enhanced production of these cytokines was observed using a combination of IL-3 and anti-IgE. We conclude from these data that, by releasing performed IL-4 and IL-4 and IL-13 generated de novo, human basophils may be centrally involved in the orchestration of allergic inflammation by providing a trigger to IL-4-mediated T helper 2 lymphocyte activation, B cell IgE switching, and increased vascular adhesion molecule expression.

Unlike NAC, ambroxol is able to not only inhibit acute mediator release from mast cells and leukocytes but also reduce immunomodulatory cytokine generation from basophils and may have beneficial effects in the treatment of allergic respiratory diseases.

There is increasing evidence that enteral histaminosis is a major cause of food intolerance resulting from dysfunctional metabolism of endogenous histamine in certain food stuffs. However, this phenomenon has been poorly characterised and, due to the lack of epidemiological data, the existence of this condition has been underestimated, which may lead to incorrect diagnosis. This short commentary highlights a stricter regimen of diagnostic procedure in order to take into account the many causes of food intolerance. The underlying mechanisms ascribed particularly to non-immunologically food reactions require more rigorous research and further work is vital.

These results compare favourably with previous studies, which have often required the use of positive selection via the Fc epsilon RI receptor, which may result in cell degranulation, or cell sorting, which cannot be applied to large cell numbers. Our method provides a reproducible technique for basophil enrichment when large numbers of functionally intact basophils are required.

Human basophils have recently been shown to rapidly produce and release interleukin (IL-)4 and IL-13 as well as histamine and eicosanoids. Since both IL-4 and IL-13 can initiate and maintain late phase allergic reactions we addressed whether some widely used anti-allergic drugs can inhibit the anti-IgE induced release of these cytokines from enriched human basophils. Basophils were enriched (47-92% purity) by Ficoll density centrifugation followed by elutriation and negative selection of contaminating cells using immunomagnetic beads. Basophils were stimulated with sub-optimal dilutions of anti-IgE in the presence or absence of various drugs and the release of histamine and cytokines were measured after 30 min and 4 h, respectively. The beta-2 agonist salmeterol, the H1-receptor antagonist terfenadine and the phosphodiesterase inhibitor theophylline inhibited the release of IL-4 and IL-13 by more than 50% following 4 h of basophil stimulation with anti-IgE. These drugs also inhibited the release of histamine following 30 min stimulation, although with less efficacy than for IL-4 and IL-13. Short preincubation of basophils with salmeterol or terfenadine before stimulation gave rise to significantly greater inhibition of histamine release but had less effect on the inhibition of cytokine release. The effects of theophylline, however, were not significantly affected by preincubation of the cells with the drug. In contrast to the aforementioned drugs, salbutamol and cetirizine were ineffective at inhibiting both histamine and cytokine release from basophils. These results suggest that a number of anti-allergic drugs may mediate their effects, in part, in reducing late phase allergic responses due to their actions on IL-4 and IL-13 secretion from basophils.