Associations between patient clinical characteristics and the presence of cytomegalovirus DNA in the bronchoalveolar lavage fluid of children with recurrent wheezing.

BACKGROUND: This study aimed to investigate the occurrence of Cytomegalovirus (CMV) DNA in the Bronchoalveolar lavage fluid (BALF) of children with recurrent wheezing and to identify associations with certain patient clinical characteristics.

METHODS: In this cross-sectional study, pediatric patients (age < 36 months) admitted to Soochow University Hospital with recurrent wheezing (≥ 4 episodes of wheezing per year) were enrolled in the study. Cytomegalovirus DNA from their BALF was detected by real-time PCR. Subpopulations of blood immunoglobulins and T lymphocytes were quantified. The clinical characteristics of patients with and without BALF CMV DNA were compared. Comparisons of non-normally distributed continuous variables between groups were made using the Mann-Whitney U-test. Comparisons of frequency distributions were made using the Chi-squared test. Spearman's rank correlation coefficient was used to evaluate correlations between the number of CMV DNA copies and continuous variables.

RESULTS: A total of 111 patients aged 4 to 36 months (median 14.0 (IQR 8.0-22.0) months) were enrolled on to the study. Cytomegalovirus DNA was detected in 51.4% of patients (n = 111) with recurrent wheeze and was more prevalent among those aged 12 to 36 months with a positive modified asthma predictive index (mAPI) (n = 38, median 23.5 (IQR 19.7-31.2) months) than in those of the same age group with a negative mAPI (n = 25, median 15.0 (IQR 13.0-19.0) months) (57.9% vs. 20.0%, p = 0.003). Bronchoalveolar lavage fluid CMV DNA copy number [median 7560 (IQR 1200-71,150) copies/mL] was positively correlated with the duration of hospitalization (r = 0.33, p = 0.013), and negatively correlated with patient age (r = - 0.41, p = 0.002) and the percentage of BALF eosinophils (r = - 0.38, p = 0.004).

CONCLUSIONS: CMV infection or reactivation in children with recurrent wheeze is associated with certain clinical characteristics, including younger age and lower levels of BALF eosinophils. Higher CMV DNA copy numbers were associated with a longer duration of hospitalization. Further studies are needed to address whether specific antiviral treatment could be beneficial for BALF CMV positive patients.