Monocyte chemoattractant protein 1 (MCP-1) in temporal arteritis and polymyalgia rheumatica

Objective-To examine the localisation of monocyte chemoattractant protein 1 (MCP-1) in the inflamed vessel wall in temporal arteritis (TA) and to meas ure MCP-1 in plasma both in patients with TA and patients with polymyalgia rheumatica (PMR). Methods-By immunohistochemical techniques MCP-1 was localised to the vessel wall in patients with TA. In TA, PMR, and healthy controls MCP-1 was quant ified by enzyme linked immunosorbent assay (ELISA) in plasma. Results-MCP-1 was localised to the majority of mononuclear cells, some smoo th muscle cells, and giant cells in the arterial biopsy specimens from 12 p atients with histologically verified TA. In all sections, including the vas a vasorum, the endothelium stained positive. In the intima 73% (range 57-91 %), in the media 49% (range 32-67%), and in the adventitia 74% (range of 62 -91%) of all cells stained positive. In plasma MCP-1 was significantly rais ed in untreated TA (n=33) and untreated PMR (n=27) compared with healthy co ntrols (n=12). Untreated TA plasma levels of MCP-1 (mean 391 pg/ml (range 8 2-778 pg/ml)) were similar to untreated PMR plasma levels (mean 402 pg/ml ( range 29-1153 pg/ml)), and no significant difference was found between the two groups of patients. In both patients with TA and patients with PMR no c orrelation was found between the plasma level of MCP-1 and the erythrocyte sedimentation rate, haemoglobin concentration, and CD4/ CD8 ratio. Conclusions-These results show that MCP-1 plays a part in the disease proce sses of TA and PMR.