Study objective: The development of BAL in children for both research and clinical purposes has been limited so far by the difficulty in establishing reference values. The aim of the study was (1) to define composition of BAL cellular components in control children and to evaluate the ability of these cells to express various cytokines, and (2) to study modifications of differential cytology and BAL cell cytokine responses in children with interstitial lung disorders.
Populations and methods: Two groups were investigated: a control group of 16 children who were concluded to be free of parenchymal lung disease after complete pulmonary investigation, and a group of 11 children with pulmonary sarcoidosis. Differential cytology was evaluated by standard techniques. BAL cell cytokine expression was studied at the level of messenger RNA (mRNA) by reverse transcription-polymerase chain reaction (RT-PCR) methods.
Results: In the control group, differential cell counts appeared to be similar to values reported in adult populations with normal distribution of the data and no influence of age. In this group, no transcripts for interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, and transforming (correction of tranforming) growth factor-beta (TGF-beta) could be detected. In children with sarcoidosis, different profiles of IL-1beta, TNF-alpha, IL-6, and TGF-beta expression were individualized which seemed to be related to the activity and/or severity of the disease, IL-6 and TGF-beta mRNA being observed only in the more severe forms.
Conclusion: These data provide information on BAL cell number and function in children. Characterization of BAL cytokine expression patterns during the course of interstitial lung diseases in children may be of great interest for evaluation of disease activity and/or severity and therefore for planning of therapy.