Transmural inflammation, including inflammatory cell (e.g., macrophages) accumulation and cytokine elaboration (e.g., tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and monocyte chemoattractant protein-1 [MCP-1]), is apparent in human and mouse AAA specimens. This evidence concerns the gene CCL2 and triple-A syndrome.