Propionibacterium acnes-derived insoluble immune complexes in sinus macrophages of lymph nodes affected by sarcoidosis.

Autor: Yoshimi Suzuki, Keisuke Uchida, Tamiko Takemura, Masaki Sekine, Tomoki Tamura, Asuka Furukawa, Akira Hebisawa, Yumi Sakakibara, Nobuyasu Awano, Tomonari Amano, Daisuke Kobayashi, Mariko Negi, Tomoya Kakegawa, Yuriko Wada, Takashi Ito, Takashige Suzuki, Takumi Akashi, Yoshinobu Eishi
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: PLoS ONE, Vol 13, Iss 2, p e0192408 (2018)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0192408
Popis: Propionibacterium acnes is thought to be a causative agent of sarcoidosis. Patients with sarcoidosis have circulating immune complexes. We attempted to detect P. acnes-derived immune complexes in sarcoid lesions.We evaluated formalin-fixed and paraffin-embedded lymph node samples from 38 sarcoidosis patients and 90 non-sarcoidosis patients (27 patients with necrotizing lymphadenitis, 28 patients with reactive lymphadenitis, 16 patients with colon cancer, 19 patients with gastric cancer) by immunohistochemistry using anti-human immunoglobulins (IgG, IgA, and IgM) and complement (C1q and C3c) antibodies, and a P. acnes-specific monoclonal antibody (PAB antibody) that reacts with the membrane-bound lipoteichoic acid of P. acnes.Small round bodies (SRBs) bound to IgA, IgM, or IgG were detected in sinus macrophages, in 32 (84%), 32 (84%), or 11 (29%) sarcoid samples, respectively, and in 19 (21%), 26 (29%), or no (0%) control samples, respectively. Some of these insoluble immune complexes (IICs) also bound to C1q and C3c. We developed a microwave treatment followed by brief trypsin digestion (MT treatment) to detect PAB-reactive SRBs bound to immunoglobulins (IIC-forming P. acnes). MT treatment revealed abundant IIC-forming P. acnes in most (89%) of the sarcoid samples and sparse distribution in some (20%) of the control samples with lymphadenitis, but no IIC-forming P. acnes was detected in control samples without inflammation. IIC-forming P. acnes were mostly bound to both IgA and IgM. The PAB-reactive antigen and immunoglobulins were both located at the peripheral rim of the IIC-forming P. acnes. Conventional electron microscopy identified many SRBs (0.5-2.0 μm diameter) in sinus macrophages of sarcoid lymph nodes with many IIC-forming P. acnes, some of which were in phagolysosomes with a degraded and lamellar appearance.P. acnes-derived IICs in sinus macrophages were frequent and abundant in sarcoid lymph nodes, suggesting a potential etiologic link between sarcoidosis and this commensal bacterium.
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