CXCL8 and chronic obstructive pulmonary disease: These data indicate that all three MAPK families, p38MAPK, ERK, and JNK, are involved in the regulation of the production of IL-8 but that only the p38MAPKγ isoform is involved in the mechanism of the corticosteroid insensitivity of IL-8 in this cell culture model of stable COPD.