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Background: Antigen detection with immunofluorescence is an efficient method for diagnosis of respiratory tract infections, but has previously not allowed for simple screening of many respiratory viruses. Pools of monoclonal antibodies against various respiratory viruses are now available, and are potentially important tools for improvement of antigen detection in nasopharyngeal samples. Objective: To evaluate the commercially available Chemicon immunofluorescence assay (IFA; respiratory viruses panel and identification kit), an indirect IFA containing a pool of monoclonal antibodies for screening for influenza A, B, respiratory syncytial virus (RSV), parainfluenza 1, 2, 3 and adenovirus, and the respective individual antibodies. Study design: Ninety-six frozen preparations from nasopharyngeal secretions or bronchoalveolar lavages were retrospectively examined with the assay, and the results compared with other IFAs for antigen detection and cell culture isolation obtained in the everyday routine. Nasopharyngeal preparations from 300 children with lower respiratory tract infections at Beijing Children's Hospital during the 1994–1995 winter season were also examined. Results: The sensitivity of the Chemicon assay compared to the combined results of routine IFA and isolation was 89% and specificity 92%. If five identifications of RSV made with the Chemicon assay alone were regarded to be truly positive, the specificity was 100%. A viral etiology was identified in 105 280 (38%) evaluable samples drawn from the Chinese children (influenza A 20%, RSV 14%, adenovirus 3% and parainfluenza 1, 2 or 3, 7%). Conclusion: One problem with the Chemicon assay was that for around 4–13% of samples there was a non-specific staining in the screening assay, necessitating stainings for verification. Despite this, the assay is an excellent tool for identification of viral respiratory tract infections, giving an increased sensitivity compared to direct immunofluorescence assays.

Background: A close relationship between outcome in patients with early-onset asthma and atopy has been reported. Allergic sensitization in early life seems to be an important risk factor for subsequent persistent asthma during childhood and adulthood. It might be valuable to evaluate atopy in patients with early-onset asthma in order to predict prognosis and take early intervention. Methods: Clinical data of 62 asthmatic children under 4 years of age were collected. The atopy status of each patient was determined by both personal allergic history (eczema and/or allergic rhinitis) and specific diagnosis of allergens (screening tests of fx5E, mx2 and Phadiatop conducted by fluoroenzyme-immunometric assay using the UniCAP100 system). The total serum IgE level was also measured. Logistic regression was used to analyze the effect of clinical characteristics on allergic sensitization. Results: There were 74.2% children who reported personal history of atopy and 33.9% reported parents' history of atopy based on the clinical data. The positive rates of fx5E, mx2, and Phadiatop were 40.3%, 14.5%, and 14.5% respectively. The total rate of allergic sensitization was 46.8% and the rate of sensitization to inhalant allergens was 24.2%. The allergic history of parent(s), the sensitization to food allergen, the age of first wheezing attack, and the total serum IgE level were main factors influencing sensitization to inhalant allergens. Conclusion: The asthmatic history of parent(s), the sensitization to food allergens, the age of first wheezing attack above 2 years and the significantly higher total serum IgE level may increase the possibility of sensitization to inhalant allergens in asthmatic children under 4 years of age.