Biomaterial Database

Propionibacterium acnes-Derived Circulating Immune Complexes in Sarcoidosis Patients. 2021

Keisuke Uchida, and Asuka Furukawa, and Akiko Yoneyama, and Haruhiko Furusawa, and Daisuke Kobayashi, and Takashi Ito, and Kurara Yamamoto, and Masaki Sekine, and Keiko Miura, and Takumi Akashi, and Yoshinobu Eishi, and Kenichi Ohashi

Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo 113-8510, Japan.

Propionibacterium acnes is a potential etiologic agent of sarcoidosis and a dysregulated immune response to the commensal bacterium is suspected to cause granuloma formation. P. acnes-derived insoluble immune complexes were recently demonstrated in sinus macrophages of sarcoidosis lymph nodes, suggesting local proliferation of the bacterium in affected organs. In the present study, we developed a method for detecting P. acnes-derived immune complexes in human blood by measuring the concentration of P. acnes-specific lipoteichoic acid (PLTA) detectable after an antigen retrieval pretreatment of plasma samples. Before pretreatment, anti-PLTA antibody was detected and PLTA could not be detected, in all plasma samples from 51 sarcoidosis patients and 35 healthy volunteers. After pretreatment, however, a significant level of PLTA (>105 ng/mL) was detected in 33 (65%) sarcoidosis patients and 5 (14%) control subjects, with 86% specificity and 65% sensitivity for sarcoidosis. In both groups, plasma anti-PLTA antibody titers did not differ between samples with and without detection of PLTA. PLTA levels were abnormally increased (>202 ng/mL) in 21 (41%) sarcoidosis patients. These findings suggest that P. acnes-derived circulating immune complexes present in human blood are abnormally increased in many sarcoidosis patients, presumably due to local proliferation of the bacterium in the affected organs.