[Serodiagnosis of human bocavirus lower respiratory tract infection in children]

Abstract

Objective: To study the application of serodiagnosis of human bocavirus (HBoV) lower respiratory tract infection in children.

Method: From January to April, 2013, samples including serum, sputum and bronchoalveolar lavage fluids (BALFs) were obtained from 714 children hospitalized with ALRI. Serums were tested for HBoV-specific IgG and IgM antibodies by ELISA and all kinds of samples were tested for HBoV DNA by quantitative real-time fluorescent PCR. The results of HBoV serologic tests, viral DNA in sputum and their combination were compared with those of HBoV DNA in serums and/or BALFs, which was considered as the "standard". Their consistence and differences were evaluated, and the diagnostic parameters including sensitivity, specificity, positive predictive value, negative predictive value, consistency rate, Kappa value and J value were calculated. Age distributions of the HBoV positive patients tested by the latter two methods were also compared.

Result: The positive rate of HBoV serology was 13.2% (94/714) . The results of HBoV serology, its DNA in sputum and their combination were all consistent with those of HBoV DNA in serums and/or BALFs (χ(2) = 91.834, 124.662, 138.643, P < 0.001 for all comparisons) . Differences were significant by McNemar test (χ(2) = 23.547, 33.440, 12.410, P all <0.001) . All the diagnostic parameters for single HBoV serologic test or single viral DNA test in sputa were approximate. However, they were improved to 70.4%, 94.8%, 38.0%, 98.6%, 93.7%, 0.463(P < 0.001), 0.65 for sensitivity, specificity, positive predictive value, negative predictive value, consistency rate, Kappa value and J value, respectively, when the methods were combined. HBoV was found positive mainly in children under 3 years of age, especially in the 1 year group. The positive rates were the highest in both group -1 year, and group -3 years was the next. However, the rate was the lowest in group >3 years and in the group -6 months.

Conclusion: Diagnostic power can be improved and age distribution can be demonstrated when serologic tests were combined with traditional sputum DNA detection in children with HBoV lower respiratory tract infection.