Increased serum levels of microvesicles in nonvalvular atrial fibrillation determinated by ELISA using a specific monoclonal antibody AD-1

Microvesicles are involved in different pathological processes such as inflammation, coagulation and tumor progression. We intended to establish an immunoaffinity capture method for detecting microvesicles and bioactive effectors carried on them using a specific homemade monoclonal antibody AD-1. By this method we investigated the association of inflammation with platelet activation in patients with nonvalvular atrial fibrillation (NVAF). A case–control study of 90 Chinese subjects selected in 3 groups: control, paroxysmal AF, and persistent AF. After capturing the microvesicles of serum using a specific monoclonal antibody AD-1, the amounts of LAP, IL-1β and P-selectin loaded on these microvesicles were quantified by either enzyme activity assay (LAP) or ELISA respectively. Compared with normal controls, the patients with persistent AF showed significantly increased serum levels of microvesicles (P < 0.001), microvesicle-bound IL-1 β (P = 0.019) and microvesicle-bound P-selectin (P = 0.001). The latter two were significantly correlated with each other (r2 = 0.371, r = 0.616, P < 0.001). The microvesicle-bound IL-1β (β = 0.570, P < 0.001) and body weight (β = 0.427, P = 0.002) were as independent predictors of platelet activation. The method was easy and reproducible. Inflammation may be involved in the activation of platelets in NVAF.