Abstract
We determined platelet-activating factor (PAF)-induced aggregation of platelets in patients with nasal allergy before and during specific hyposensitization therapy. In addition, we determined the IgE, IgG level in the serum and eosinophil counts in the circulating blood. Before hyposensitization therapy, it was observed that the rate of PAF-induced aggregation of platelets tended to be more increased in the patients with a high level of serum IgE or IgG, compared with that in the patients with a low level of IgE or IgG. On the other hand, during hyposensitization therapy, the correlation between PAF-induced maximal aggregation rates and serum IgE, IgG levels changed from a positive correlation to a negative correlation. We supposed that the increase in the rate of PAF-induced aggregation of platelets was caused by IgE and IgG molecules binding to each Fc receptor on the platelet membrane. We further surmised that the reactivity of platelets was reduced during hyposensitization therapy because of decreased numbers of IgE and IgG molecules binding to the platelet membrane. Moreover, it appeared that the IgE and IgG molecules bound to the platelet membrane stimulated platelet activity. These findings suggest that PAF-induced aggregation of platelets in nasal allergies may be useful in evaluating the efficacy of specific hyposensitiza- tion therapy.
