Loss of Erythrocyte Complement Receptors (CR1; CD35) in Patients with Acute Episodes of Septicaemia or Bacterial Meningitis

Abstract

14 patients with septicaemia or bacterial meningitis were examined for serum levels of erythrocyte complement receptors CR1 (C3b/C4b; CD35) by an enzyme-linked immunosorbent assay and levels of circulating immune complexes (IC) by a polyethylene glycol precipitation complement consumption method, and concentrations of complement C3d split products in plasma by intermediate gel rocket immunoelectrophoresis. The CR1 receptor levels were significantly lower on day 7–8 after admission than on day 1–2 (p = 0.01), and than the levels 3–4 months later (p = 0.002). Both the levels of IC in serum and the C3d concentrations were significantly higher on day 7–8 than 3–4 months later (p = 0.02 and p = 0.004). The mechanism behind a temporary decreased expression of CR1 in patients with acute episodes of septicaemia or purulent meningitis is not fully known, and further investigations are needed to clarify whether this reduction in erythrocyte CR1 causes an impaired disposal of IC in patients with infections