BETA(2)-ADRENERGIC RECEPTORS ON PERIPHERA L-BLOOD MONONUCLEAR-CELLS IN PATIENTS WITH RHEUMATIC DISEASES

The pathogenesis of rheumatic diseases is only incompletely understood , and an imbalance of the immune system seems to play a central role. There ist growing evidence that the autonomic nervous system influence s the immune response by stimulation and modulation of the beta(2)-adr energic receptors (beta(2)R) on lymphocytes. Aim of the study: The pre sent study aimed at evaluating the density and equilibrium constants ( KD) of beta(2)R on peripheral blood mononuclear cells (PBMC) in patien ts with chronic rheumatic diseases. Patients and methods: Characterist ics of beta(2)R on PBMC were determined in 10 patients with rheumatoid arthritis (RA) with low systemic disease activity (group 1), 11 patie nts with RA and high systemic disease activity (group 2), 25 patients with different connective tissue diseases (group 3), and 9 healthy don ors (group 4) using a radioligand binding assay with (125)Iodocyanopin dolol. Results: Compared to normal donors (group 4, mean+/-sem, 3,960/-372 binding sites/cell, bs/c) the density of beta(2)R was significan tly decreased in all patient groups (group 1, 2,418+/-95 bs/c, p < 0.0 1; group 2, 1,850+/-134 bs/c, p < 0.001; group 3, 1,360+/-16 bs/c, p < 0.001). The number of beta(2)R in patients with RA and high disease a ctivity (group 2) was significantly lower than in RA patients with low systemic disease activity (group 1). In all three patient groups, a s ignificant negative correlation between beta(2)R density and parameter s of the systemic disease activity was observed. Nine patients with sy stemic lupus erythematosus showed a significant negative correlation b etween beta(2)R density and serum anti-ds-DNA antibody levels (r=-0.57 ; p < 0.01). Conclusion: These results obtained demonstrate the close correlation between the number of beta(2)R on PBMC and the disease act ivity in patients with rheumatic diseases. However, in the pathogenesi s of immunologically mediated diseases the role of beta(2)R stimulatio n and modulation remains to be clarified.