MMP8 and cystic fibrosis: In these CF children, we also assessed serum expression of the whole panel of ECM markers and similarly to our observations in adult CF patients, when CF children were stratified according to FEV1 and VC below or above 80% or a ratio of FEV1/VC below or above 70%, we found significantly increased serum levels of MMP-8 and MMP-9 (Fig. 3) with each of these stratification indicative of moderate to severe CF lung disease.