Soluble CD40 ligand in morbidly obese patients: effect of body mass index on recovery to normal levels after gastric bypass surgery.

Importance In recent years, the CD40/CD40L system has been implicated in the pathophysiology of severe chronic inflammatory diseases. Recently, obesity has been described as a low chronic inflammatory disease, so this system could also be involved in the inflammatory process. Objective To study soluble CD40 ligand (sCD40L) and other factors implicated in coagulation (plasminogen activator inhibitor 1, antithrombin III, and fibrinogen) and inflammation (C-reactive protein) in patients with morbid obesity and different body mass indexes (BMIs) (calculated as weight in kilograms divided by height in meters squared), before and after weight loss induced by bariatric surgery. Design Plasma samples were obtained before and after a bariatric surgery intervention. Several inflammatory markers were then studied (sCD40L, plasminogen activator inhibitor 1, antithrombin III, and C-reactive protein). The values obtained were compared with a control group of nonobese persons. Participants Thirty-four morbidly obese patients undergoing gastric bypass surgery and 22 normal-weight controls matched for age and sex. Interventions A Roux-en-Y gastric bypass was performed in morbidly obese patients. Main Outcome Measures Levels of sCD40L, plasminogen activator inhibitor 1, antithrombin III, fibrinogen, and C-reactive protein 12 months after bariatric surgery. Results Obese men showed a tendency for decreased plasma sCD40L levels 1 year after surgery (mean [SEM], 246.5 [70.4] pg/mL before vs 82.2 [23.2] pg/mL after surgery; P  Conclusions and Relevance Increased BMI, but not sex, influences recovery to normal levels for the markers studied, possibly indicating a worse prognosis.