Differential immune responses to acute lower respiratory illness in early life and subsequent development of persistent wheezing and asthma.

BACKGROUND

Recent epidemiologic evidence suggests that 2 wheezing syndromes coexist in early life: transient wheezing, limited to early childhood, and persistent wheezing, which starts in early childhood and persists beyond that age.

OBJECTIVE

Whether the nature of the immune response occurring during acute lower respiratory illnesses (LRIs) in infancy differs between these 2 groups of wheezers has yet to be determined.

METHODS

We compared total serum IgE levels and peripheral blood eosinophil counts obtained during the acute phase of the first LRI with those obtained during the convalescent phase or with well-baby samples in persistent (n = 49) and transient early wheezers (n = 88), as well as in children who had only nonwheezing LRIs (n = 43) during the first 3 years of life.

RESULTS

Total serum IgE levels were significantly higher (P =.008) during the acute phase compared with the convalescent phase of the LRI in persistent wheezers, a response not observed in transient early wheezers (P =.7). Peripheral blood eosinophil counts were significantly reduced during the acute phase of the LRI (P =.009) in transient early wheezers, a response not observed among persistent wheezers (P =.7). Acute responses in children who had nonwheezing LRIs only were similar to those seen in transient early wheezers.

CONCLUSION

Alterations in acute immune response to viral infection may be detected at the time of the first wheezing episode in subjects who will go on to have persistent wheezing symptoms.