OBJECTIVETo measure levels of interleukin-4 (IL-4) and interferon-gamma (INF-γ) in the bronchoalveolar lavage fluid (BALF) of children with refractory Mycoplasma pneumoniae pneumonia (RMPP), and to investigate changes in local Th1-Th2-type cytokine levels in children with RMPP and their significance.

METHODSA total of 42 children with RMPP were divided into atopic (n=11) and non-atopic groups (n=31) according to whether they had eczema, allergic rhinitis, urticaria, and family history of allergic disease. The study also included a control group of 12 children with bronchial foreign bodies who underwent foreign body removal and were re-examined by fiberoptic bronchoscopy four weeks later. The different cells in BALF from all children were analyzed, and the levels of IL-4 and INF-γ in BALF were measured using enzyme-linked immunosorbent assay.

RESULTSCompared with the control group, the total number of cells in BALF from children with RMPP increased significantly (P<0.05), the increase mainly accounted for by neutrophils (P<0.01), and levels of IL-4 and INF-γ in BALF from children with RMPP increased significantly (P<0.05). Compared with the control group, levels of IL-4 and INF-γ in BALF in the atopic group increased significantly (P<0.05). The level of INF-γ in BALF in the non-atopic group also increased significantly (P<0.05). There were no significant differences in INF-γ/IL-4 ratio among all groups (P>0.05).

CONCLUSIONSSignificant increase in cell numbers, especially neutrophils, as well as IL-4 and INF-γ levels, can be seen in BALF from children with RMPP, but there is no change to the INF-γ/IL-4 ratio. This indicates a significant local inflammatory response in children with RMPP, but there is no evidence of Th2-dominated inflammatory response.