An Association Between the Acute Phase Reponse and Patterns
The aim of this research was to determine whether all memory T cells have the same propensity to migrate to the joint in patients with juvenile idiopathic arthritis. Paired synovial fluid and peripheral blood mononuclear cell proliferative responses to a panel of antigens were measured and the results correlated with a detailed set of laboratory and clinical data from 39 patients with juvenile idiopathic arthritis. Two distinct patterns of proliferative response were found in the majority of patients: a diverse pattern, in which synovial fluid responses were greater than peripheral blood responses for all antigens tested; and a restricted pattern, in which peripheral blood responses to some antigens were more vigorous than those in the synovial fluid compartment. The diverse pattern was generally found in patients with a high acute phase response, whereas patients without elevated acute phase proteins were more likely to demonstrate a restricted pattern. We propose that an association between the synovial fluid T cell repertoire and the acute phase response suggests that proinflammatory cytokines may influence recruitment of memory T cells to an inflammatory site, independent of their antigen specificity. Additionally, increased responses to enteric bacteria and the presence of




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7 T cells in synovial fluid may reflect accumulation of gut associated T cells in the synovial compartment, even in the absence of an elevated acute phase response. This is the first report of an association between the acute phase response and the T cell population recruited to an inflammatory site.


Large numbers of memory T cells are found in the inflamed joint, possibly facilitated by their enhanced capacity to adhere to vascular endothelium of inflamed synovium. It is unclear, however, whether all memory T cells have the same propensity to migrate to the inflamed joint, independent of their antigen specificity. If this were the case then it would be expected that synovial fluid mononuclear cell (SFMC) proliferative responses to a wide range of antigens would be enhanced as compared with the peripheral blood mononuclear cell (PBMC) responses, provided that the individual had previously been exposed to those antigens. Alternatively, it has been suggested that patterns of antigen induced SFMC proliferation reflect an inciting or perpetuating antigenic stimulus. In this situation, accumulation of a specific population of T cells in an inflamed joint would be reflected by an antigen-specific SFMC proliferative response. We hypothesized that all memory T cells would have the same propensity for migration into the joint, irrespective of their antigen specificities. The aim of the present study was to test the hypothesis in juvenile idiopathic arthritis (JIA) - a group of diseases characterized by chronic inflammation of synovial joints in childhood.