PiM subtypes in bronchiolitis.

: Decreased alpha-1-antitrypsin (alpha 1AT) levels have been observed in children affected by bronchiolitis; however, variant alleles Pi (S, Z) which are usually associated with reduction of the inhibitor do not show a higher incidence in children affected by this disease. Subtypes M2 and M3 of alpha 1AT have recently been considered to play a role in the development of allergic states in children as well as in chronic obstructive lung disease in adults. In the present study we have investigated the incidence of PiM subtypes in 98 children affected by bronchiolitis. No greater incidence of subtypes M2 and M3 was observed in these children than in controls. These results rule out the hypothesis of a pathogenetic role of M subtypes in the development of bronchiolitis in children.