Serum Clara cell protein and atopic phenotype in children up to 2 years of age.

BACKGROUND: Low value of serum Clara cell protein (CC16) is associated with bronchial hyperreactivity in children.

OBJECTIVE: To evaluate the serum CC16 in relation to atopy and previously manifested LRTD.

METHODS: In the population of 163 healthy 5- to 24-month-old children, atopy was determined by Phadiatop-infant (serum-specific IgE≥0.35 kUA/L), serum CC16 by ELISA, while data on previously manifested low respiratory tract diseases (LRTD) were collected from the Health Care Center database.

RESULTS: In atopic children, serum CC16 negatively correlated with age (r -.281, P=.041, n=53), while in nonatopic children, this correlation was positive (r .200, P=.036, n=110). Atopic ≥8-month-old children with previously manifested LRTD had lower level of CC16 (3.07 ng/mL) in relation to atopic children without LRTD at the same age (6.51 ng/mL), P=.029 (value of serum CC16≥4.8 ng/mL indicates atopic phenotype without LRTD 75% sensitivity, 87.5% specificity). In 8- to 24-month-old children with previously manifested pneumonia, serum CC16 was lower in atopic (2.9 ng/mL) in relation to nonatopic children (3.7 ng/mL), P=.029 (serum CC16 ≤3.4 ng/mL indicating atopy in the group of children with pneumonia, sensitivity 100%, and specificity 77%). Atopic 8- to 24-month-old children with previously manifested pneumonia had lower CC16 in relation to other atopic children in this age (P=.021) (for cutoff CC16≤3.4 ng/mL sensitivity 100%, specificity 77%), and also often chronic wheezing (atopic with pneumonia 83.3%, n=5/6 vs atopic without pneumonia 21.4%, n=3/14), P=.018.

CONCLUSION: Low serum CC16 is associated with previously expressed pneumonia and chronic wheezing in atopic children.