Objective: To evaluate protein profiles and Fc gamma receptor lib (FCGRIIB) expression in abdominal aortic aneurysm (AAA) compared to the expression in normal aortas. Methods: We performed a protein array to study the protein expression profiles within AAA and normal aortic tissues. FCGRIIB was found to be significantly elevated in AAA samples. Quantitative PCR and Western blot analyses were performed to study the expression of FCGRIIB in AAA compared to that in normal aortic tissue. Immunohistochemistry was used to locate FCGRIIB and the B cell marker CD19 in AAA and normal aortas specimens. Results: FCGRIIB was significantly elevated in AAA tissues in both mRNA (AAA vs. normal control: about 5.8 folds, p < 0.001) and protein levels (AAA vs. normal control: about 6.3 folds, p < 0.001). In AAA specimens, immunohistochemistry revealed that FCGRIIB localized to the area of inflammatory infiltrates, which consisted of CD 19(+) B cells and other inflammatory cells. FCGRIIB and CD19 were undetectable in normal aortas. Conclusions: FCGRIIB was significantly elevated in AAA tissues compared to normal aortas. FCGRIIB may be involved in the pathogenesis of AAA by regulation of inflammatory reactions. (C) 2017 Published by Elsevier Inc.