DIMINISHED ABILITY OF ERYTHROCYTES FROM PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS TO LIMIT OPSONIZED IMMUNE-COMPLEX DEPOSITION ON LEUKOCYTES AND ACTIVATION OF GRANULOCYTES

Objective. To compare the ability of normal erythrocytes and erythrocy tes from systemic lupus erythematosus (SLE) patients to bind immune co mplexes (IC), thereby inhibiting IC deposition on polymorphonuclear le ukocytes (PMN) and the consequent induction of a PMN respiratory burst (RE), Methods. The binding of fluorescein isothiocyanate-labeled IC i n 75% autologous serum to whole blood cells or isolated leukocytes fro m 17 SLE patients and 10 controls was assessed by flow cytometry, Reac tive oxygen metabolite (ROM) production by PMN was measured as the int racellular oxidation of dihydro-rhodamine 123, on stimulation with unl abeled IC. Results, Erythrocyte-mediated inhibition of IC uptake by PM N reached a mean +/- SD maximum of 68 +/- 18% in controls and 29 +/- 5 1% in SLE patients (P < 0.05) and, in the patients, correlated inverse ly with disease activity, In the presence of erythrocytes from various donors, IC binding to a standard preparation of PMN and their ROM pro duction were inversely proportional to the number of type 1 complement receptors (CR1) per donor erythrocyte. Thus, the ROM production was h igher in the presence of SLE patients? erythrocytes (125 +/- 67 CR1/er ythrocyte) than with erythrocytes from controls (235 +/- 118 CR1/eryth rocyte). Conclusion. Erythrocytes from SLE patients are defective in p rotecting their PMN against IC deposition and induction of the RB.