MODULATION OF C4B-BINDING PROTEIN ISOFORMS DURING THE ACUTE-PHASE RESPONSE CAUSED BY ORTHOPEDIC-SURGERY

Orthopedic surgery is described as an event with a high risk of thromb oembolic diseases. This is probably a consequence of a synergistic com bination of different risk factors in the patients subjected to this t ype of surgery, including age, immobilization, anesthesia and differen t hypercoagulable states. After surgery patients develop an acute-phas e response that leads to changes in several plasma proteins. One of th ese proteins is the complement regulator C4b-binding protein (C4BP). W e have recently shown that in some acute-phase patients C4BP is incorr ectly controlled (with elevation of the C4BP beta-containing isoforms) , leading to a potential hypercoagulable state by decreasing the plasm a levels of free (active) protein S. Here we have studied whether pati ents subjected to orthopedic surgery have an appropriate modulation of the C4BP isoforms during their postoperative acute-phase responses. W e have analyzed the evolution of the C4BP isoforms in serial samples f rom 11 patients who have undergone knee (or hip) prosthesis surgery (m ean age 70 years), or scoliosis surgery (mean age 18 years). Our data suggest a similar evolution of C4BP isoforms in all these patients, wi th an almost exclusive increase of C4BP isoforms lacking C4BP beta pol ypeptides and steady levels of free protein S.