Mediators in the asthmatic child.

Prostaglandins (PGF) are known to occur in premature babies with hyaline membrane disease and so the levels of PGE during growth have been investigated. The levels are lower in children than in adults; but this fact cannot explain the high resistance to air flow in infants. The release of mediators has been shown in children and in adults. Release of histamine from circulating basophils occurs when the suspected allergenic extract is mixed with the blood of the asthmatic child. Other mediators have not been found in young children. Cutaneous tests and respiratory challenges demonstrate indirectly the action of mediators in children, but not in infants. Between 5 and 15 years of age, the frequency and type of response to these tests are not significantly different. One may assume that, at least within these age limits, release of mediators is similar qualitatively.