[Defects in opsonization activity of the serum of patients with chronic arthritis].

The opsonizing capacity of sera from 22 patients with rheumatoid arthritis (RA), from 14 with psoriatic arthritis (AP), from seven with ankylosing spondylitis, and from healthy control persons was investigated by luminol-dependent chemiluminescence, induced during yeast phagocytosis of normal polymorphonuclear leukocytes. The chemiluminescence response using opsonizing sera was compared to that induced by no-opsonized yeast and the opsonizing capacity was expressed as a percentage. For the opsonization, fresh native serum, in some experiments Mg2+-EGTA and EDTA-treated serum, was used. In RA and AP sera, a significantly diminished opsonizing capacity (p less than 0.005) was observed. In healthy controls and in SPA patients, the opsonizing capacity of their sera was over 200%, while in seronegative RA patients, it was only 175%, in seropositive RA 125%, and in AP 150% was measured. There was no correlation between opsonizing capacity and complement or immunoglobulin content of the investigated sera. The amount of C3b, IgG and IgM covalently bound to yeast particles was determined, too. Yeast particles bind significantly less (p less than 0.01) IgG when opsonized with RA and AP sera, while a higher relative amount of IgM (p less than 0.01) was bound to yeast incubated in the sera of seropositive RA patients. No significant differences in the C3b binding were observed.