IL4 and Pleural effusion: The <i>χ</i> <sup>2</sup> text and Mann-Whitney <i>U</i> Test analysis indicated that ESR, CD4<sup>+</sup> <i>T</i> cells, NK cells, IL-4, duration of fever, and pleural effusion were significant predictors of NP in children with MPP (<i>P</i> < 0.05).