PT - JOURNAL ARTICLE AU - Yoshimi Hatano AU - Tsuyoshi Kasama AU - Hideaki Iwabuchi AU - Ryosuke Hanaoka AU - Hiroko T Takeuchi AU - Lu Jing AU - Yoshiaki Mori AU - Kazuo Kobayashi AU - Masao Negishi AU - Hirotsugu Ide AU - Mitsuru Adachi TI - Macrophage inflammatory protein 1 alpha expression by synovial fluid neutrophils in rheumatoid arthritis AID - 10.1136/ard.58.5.297 DP - 1999 May 01 TA - Annals of the Rheumatic Diseases PG - 297--302 VI - 58 IP - 5 4099 - http://ard.bmj.com/content/58/5/297.short 4100 - http://ard.bmj.com/content/58/5/297.full SO - Ann Rheum Dis1999 May 01; 58 AB - OBJECTIVE To determine the contribution made by synovial fluid (SF) neutrophils to the augmented expression of macrophage inflammatory protein 1 α (MIP-1α) in rheumatoid arthritis (RA).METHODS Neutrophils were isolated from samples of SF from RA patients and peripheral blood (PB) samples from RA patients and healthy controls. Cell associated MIP-1α was visualised immunohistochemically, and cell associated MIP-1α as well as MIP-1α secreted into the SF was assayed by ELISA. Steady state expression of MIP-1α mRNA was assessed by reverse transcription polymerase chain reaction (RT-PCR).RESULTS Freshly isolated SF neutrophils contained significantly higher concentrations of both MIP-1α protein and its transcript than PB neutrophils from either RA patients or healthy controls; incubation in the absence or presence of tumour necrosis factor α for 24 hours resulted in a significant increase in MIP-1α secretion by RA SF neutrophils compared with neutrophils obtained from either normal PB or RA PB; and expression of MIP-1α by SF neutrophils was well correlated with both RA disease activity and SF mononuclear cell (MNC) counts.CONCLUSION Expression and secretion of MIP-1α by SF neutrophils may be indicative of local and systemic inflammation in RA. Moreover, this C-C chemokine may contribute to the recruitment of MNCs from the bloodstream into synovial joints and tissues.