Figure 2.

P. acnes in sarcoid granulomas detected by immunohistochemistry with PAB antibody. Hematoxylin–eosin stain and immunohistochemistry with P. acnes-specific PAB antibody are shown pairwise. PAB-reactive P. acnes (resulting in brown color) are observed in non-caseating epithelioid cell granulomas of the lymph node (A,B), lung (C,D), and ocular epiretinal membrane (E,F) from patients with sarcoidosis. Mainly small round and occasionally large ovoid positive-signals are observed in granuloma cells, irrespective of the sites at which the granuloma formed. All photos are original. Scale bar: 50 μm.