The effect of immunotherapy on the in vitro productions of histamine, prostaglandin E2 and leukotriene C4 in asthmatic children.

ABSTRACT

In order to elucidate the working mechanisms of immunotherapy (IT), the in vitro productions of histamine, prostaglandin E2 (PGE2) and leukotriene C4 (LTC4) were studied in 18 newly diagnosed and 20 hyposensitized (greater than 2 yr) asthmatic children. All were sensitive to house dust and dust mites. (D. pteronyssinus). Ten age-matched normal children were included as control. Polymorphonuclear (PMNs) and mononuclear (MNCs) leukocytes were separated by density gradient centrifugation and dextran sedimentation. PMNs (2 x 10(7) cells/ml) and MNCs (2 x 10(7) cells/ml) were stimulated with mite allergen (10 micrograms/ml) and calcium ionophore A23187 (1 microgram/ml) for 15 minutes. The plasma and culture supernatant (sup) histamine levels and sup PGE2 and LTC4 were measured by RIA. The results showed; 1) When compared to new patients, the treated patients had much lower plasma and sup histamine (p less than 0.001), no matter whether PMNs and MNCs were stimulated with allergen or A23187 and the normals had the lowest histamine level among 3 groups; 2) LTC4 in A23187-stimulated sup was lower in treated patients (p less than 0.05); 3) The PGE2 in allergen-stimulated sup was markedly increased in treated patients as compared to new patients (p less than 0.01) and the PGE2 in sup of normals was also much higher than that of new patients. Thus, immunotherapy is able to reverse the abnormal secretory pattern of inflammatory mediators of allergic patients, and this change may account, partly, for its clinical effectiveness.