Venous blood was drawn using a serum separator tube and allowed to clot for 30-45 minutes at room temperature before centrifugation for 15 minutes at approximately 1,000g. Serum was immediately stored frozen in aliquots at -20°C until assays for IL-10, MMP-7, and MMP-9 were performed. IL-10 was assayed by the high sensitive EBioscience technique, Bender MedSystems GmbH 1030 Vienna, Austria. Circulating MMP-7 and MMP-9 levels were examined in serum using the Quantikine Human MMP-7-ELISA and Quantikine Human MMP-9-ELISA (Quantikine, R&D System, Inc., Minneapolis). Serum levels were expressed as pg/ml. Levels above the mean were categorised as the high level, and levels below the mean were categorised as the low level.