[Latent autoantibodies to cardiolipin in the blood serum of healthy subjects].

Pooled health blood donors' sera were fractionated by gel filtration and/or ion exchange chromatography on strong anion-exchanger. Measurement of anticardiolipin antibodies levels by ELISA method shows that gel filtration at pH 4.05 and 9.2 (complex-degradation conditions) leads to increase in summary levels while after elution at neutral pH such an effect did not appear. Light increasing of anticardiolipin levels was also noted after fractionation on QAE-Sephadex. Data obtained state that anticardiolipin autoantibodies amount in sera is greater than it can be detected by direct measurement in untreated serum samples. Existence of "hidden" anticardiolipin autoantibodies supposes the hypothesis about alternative way of humoral immunity regulation by blocking anti-self antigens activities with serum biopolymers.