186 M. Edvinsson et al. probably passed into a chronic state of persistence. Further studies are needed to establish the role of inﬂammation, which is possibly caused in some patients by slow-growing bacteria, including C. pneumoniae, in the pathogenesis of thoracic aortic aneurysm and aortic dissection. Acknowledgements We thank Ylva Molin for technical assistance with PBMC extraction and RNA extraction and Victoria Arameshk for clinical data collection. This study was supported by grants from The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS), the Family Olinder- Nielsen’s Foundation, and the Uppsala County Association against Heart and Lung Diseases. Declaration of interest: The authors report no conﬂicts of interest. The authors alone are responsible for the content and writing of the paper. References 1. Isselbacher EM. Thoracic and abdominal aortic aneurysms. Circulation. 2005;111:816–28. 2. Mukherjee D, Eagle KA. 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