ABSTRACT
<p><b>OBJECTIVE</b>To study the status of Th1/Th2 immune response and the value of the detection of cytokines in bronchoalveolar lavage fluids (BALF) by examining the levels of IFN-γ and IL-4 in BALF and serum in children with severe Mycoplasma pneumonia (MPP).</p><p><b>METHODS</b>The levels of IFN-γ and IL-4 in BALF and serum were measured using ELISA in 25 children with severe MPP, 25 children with mild MPP and 25 children with foreign body in bronchus.</p><p><b>RESULTS</b>The levels of IL-4 and IFN-γ and the IL-4/IFN-γ ratio in BALF in children with severe MPP were significantly higher than those in children with foreign body in bronchus (P<0.01 or P<0.05). The serum levels of IL-4 and the IL-4/IFN-γ ratio in children with severe MPP were significantly higher than those in children with foreign body in bronchus (P<0.01) or with mild MPP (P<0.05). The levels of IL-4 and the IL-4/IFN-γ ratio in BALF were significantly higher than in serum (P<0.05).</p><p><b>CONCLUSIONS</b>The data suggest that the imbalance of Th1/Th2 exists in children with severe MPP and it seems to represent a predominant Th2-like cytokine response. The detection of cytokines in BALF appears to be more sensitive than in serum and may be of value in the diagnosis and therapy of MPP.</p>