Leukaemia inhibitory factor (LIF) production in pleural effusions: comparison with production of IL-4, IL-8, IL-10 and macrophage-colony stimulating factor (M-CSF).

Leukaemia inhibitory factor (LIF), a pleiotropic cytokine detected in various inflammatory body fluids, plays a poorly defined role in the pathogenesis of human disease. This study was conducted to correlate the LIF concentrations in pleural effusions with the type of pathology and to compare its levels with those of IL-4, IL-8, IL-10 and M-CSF for a given pathology. Pleural fluids from 97 patients were assayed for cytokines by specific ELISAs. The concentrations of all cytokines tested were higher in infectious pleural effusions than in other pathologies (malignant or transudative). The lowest levels were observed for transudates. Significant differences were noted between pathology groups for each cytokine. A good correlation was observed between LIF and IL-8 for malignant effusions [regression correlation coefficient (RC) = 0.480, P < 0.01], between LIF and IL-4 for infectious disorders (RC = 0.543, P < 0.05) between LIF and IL-10 for transudates (RC = 0.798, P < 0.001) and between M-CSF and IL-8 in all pathologies tested except for primitive neoplasia (P < 0.05). The LIF concentration in pleural space seems to be strongly associated with the intensity of inflammatory reaction. The LIF production appears to have different regulatory patterns between aetiologic groups.