Monocyte chemotactic protein-1 production and its correlation with disease activity and T-cell subsets in synovial fluid in psoriatic arthritis patients

ABSTRACT

Psoriatic arthritis [PsA] is a chronic inflammatory arthritis characterized by infiltration of the skin and joints with activated T lymphocytes. The latter have been implicated in both the initiation and maintenance of inflammatory lesions at these sites and it is mediated by the local production and secretion of chemotactic cytokines. To evaluate the role of monocyte chemotactic protein-1 [MCP-1] in the immunopathogenesis of PsA. Also, to find out whether evidence exists for a causal relationship between MCP-1 levels in synovial fluids and T cells recruitment to lesional sites during acute and chronic synovitis and its relation to disease activity in psoriatic arthritis patients. Thirty PsA patients were recruited for this study. They were subdivided into two groups Group I 15 patients with synovitis less than 6 months' duration [acute PsA]. Group II 15 patients with synovitis more than 6 months' duration [chronic PsA]. The clinical activity of the disease was assessed by using modified disease activity score 28 [DAS28]. Their results were compared to 15 healthy age and sex matched volunteers [group III]. Peripheral blood [PB] and synovial fluid [SF] were obtained from PsA arthritis patients; also PB was obtained from normal controls. Immune cell populations in PB and SF samples were assessed with immunofluorescent labeling and flow cytometry, levels of soluble MCP-1 were determined in PB and SF samples with quantitative ELISA. DAS28 was significantly higher in group I [acute PsA] patients than group II [chronic PsA patients] [p<0.01]. CD4+, CD8+ T cells were significantly elevated in SF as compared to PB of acute but not chronic PsA patients and the majority of these cells expressed CD45RO [p<0.01]. Plasma MCP-1 levels were elevated in PsA [whether acute or chronic] relative to normal controls [p<0.01]. SF MCP-1 levels were significantly higher than paired plasma samples in acute PsA patients only [p<0.01]. A highly significant positive correlation was observed between MCP-1 levels in SF and DAS28 and also with T cell numbers in SF of acute PsA patients [p<0.01]. The elevated concentration of MCP-1 is concomitant with T cell infiltration in SF of acute PsA patients. This suggests that MCP-1 mediated chemotaxis is involved in the recruitment of T lymphocytes particularly memory cells into the synovial fluid in PsA during acute synovitis which is associated clinically with severely active disease and thus could be considered as an early inflammatory marker in acute PsA