In situ detection of Chlamydia pneumoniae, C. trachomatis, and cytokines among cardiovascular diseased patients from the Amazon region of Brazil Larissa S Freitas,1 Núbia Caroline C Almeida,1 Maria Alice Freitas Queiroz,1 Marcelo M Zaninotto,2 Hellen T Fuzii,3 Alfredo Ribeiro-Silva,4 Antonio CR Vallinoto,1 Marluísa OG Ishak,1 Juarez AS Quaresma,3 Ricardo Ishak1 1Virus Laboratory, Institute of Biological Sciences, Federal University of Para, 2Hospital of Clinic Gaspar Viana, 3Laboratory of Immunopathology, Nucleus of Tropical Medicine, Federal University of Para, Belém, 4Departament of Pathology, Medical School of Ribeirão Preto, University of Sao Paulo, São Paulo, Brazil Background: Chronic coronary artery disease has been associated, as a consequence of the local inflammatory reaction with previous or persistent infection with Chlamydia pneumoniae, which led to the investigation of the association of cardiovascular disease and previous infection with C. trachomatis and the role of cytokine profile (in situ) markers in the vascular system tissues. Methods: Sixty-nine biopsies were collected for immunohistochemical analysis for the presence of IL-6, IL-8, TNF-a, IFN-g, TGF-β, and IL-10, in 16 fragments from atheromatous plaques, 32 aorta fragments, and 21 valve fragments, using a tissue microarray technique for paraffin embedded tissues. Results: Most patients undergoing revascularization surgery were men >50 years, while those undergoing valve replacement were mostly women