Abstract
Ferritin contents in peripheral blood or synovial fluid leukocytes from 24 RA patients and 14 healthy donors were measured by 2-sites immunoradiometric assay as supernatants after cells with 5 times repetition of freezing and thawing were centrifuged at 3000 r.p.m. for 20 min. Ferritin contents per a single cell (fg/cell) were calculated from the value of measured supernatants divided by the number of cells. Polymorphonuclear cells (PMN) and mononuclear cells (MNC) were separated from huffy coats or synovial fluid with heparin (10 u/ml) and hyaluronidase (20 u/ml) by Conray-Ficoll gradient sedimentation method. Peripheral blood mononuclear cells (1×106 cells/ml; PBM) were suspended in RPMI 1640 medium containing 10% fetal calf serum and cultured in 5% CO2 incubator at 37°C for 7 days with or without addition of different concentration of ferric citrate ranged from 0.01 to 1 mM. Ferritin contents in PBM were increased with addition of ferric citrate in dose-dependent manner. Ferritin contents in peripheral blood PMN (mean ± SEM=5.3±2.6 fg/cell, n=16) and MNC (9.3±3.3 fg/cell, n=16) of RA patients were not significantly different from that of healthy controls (PMN: 4.1 ±2.6 fg/cell, n=14 and MNC: 11.1±2.7 fg/cell, n=15) . It was, however, found in both groups that ferritin contents in MNC were higher than that in PMN. Ferritin contents in synovial fluid PMN (29.7±9.5 fg/cell, n=16) and MNC (62.4±7.1 fg/cell, n=16) of RA patients were remarkably higher than that in peripheral blood leukocytes.
