Study of IgE-dependent sulphidoleukotriene cellular releasability

Cellular releasability of mediators, as termed by Lichtenstein and Conroy (1), can be triggered by interaction with allergens, anti-IgE antibodies or other agonists. Genetic factors can also influence the cell releasability. We studied 104 subjects, including 92 atopic patients (62 sensitive to D. pteronyssinus and 54 sensitive to Lolium perenne) and 12 healthy controls. Sulphidoleukotriene (sLT) production was measured after allergen and anti-IgE stimulus with CAST-ELISA, and histamine release using a fluorometric method. We found a significant sLT production after anti-IgE stimulation, higher than in basal conditions with medium alone. The sLT production was also significantly higher in sensitive patients than in healthy controls. We found 14.5% of healthy and atopic subjects to be non-responders to anti-IgE stimulus. We also found a positive and significant correlation between sLT production and histamine release. Moreover, we observed a significant positive correlation between IgE-dependent and antigen-specific sLT release. We also noticed a decrease in sLT production and a decrease in histamine release with aging. Male patients had a sLT production significantly higher than female patients. With respect to clinical diagnosis, the group of patients with rhinitis had the highest mediator production. Finally, pollinic patients studied during the spring had a higher sLT production to anti-IgE than those studied out of this season. We conclude that quantification of sLT production after anti-IgE stimulation is a useful method to study cell releasability of mediators and that such releasability is higher in atopic patients than in healthy donors. We must emphasize the usefulness in allergy diagnosis of relying not only on the use of methods demonstrating the existence of sensitization to an allergen, but also of techniques able to quantify the ability to respond to that allergen. In this way we would be able to evaluate the clinical and immunological evolution of patients and to follow up the efficacy of their treatment.