[Quantitative analysis of immunoglobulins using the hemagglutination-inhibition test. II. Comparison with the results of radial immunodiffusion].

Stable erythrocytic diagnostic reagents have been prepared on the basis of formalinized erythrocytes coated with purified IgG, IgM, IgA ans sIgA with the aim of the quantitative determination of immunoglobulins in the hemaglutination inhibition (HAI) test. The sensitivity of the HAI test in the quantitative determination of immunoglobulins is 50--100 times higher, but its accuracy is lower than those of radial immunodiffusion (RID). This is the cause of a high variability in indices of serum immunoglobulin levels in healthy persons. The parallel study of sera with altered immunoglobulin levels by means of the HAI test and RID revealed, as a rule, a good correlation of their results. The proteolytic breakdown and aggregation of immunoglobulins produced similar changes in the results of the HAI test and RID. The possibility of using the HAI test for the study of local immune response in infections diseases has been shown by study of coprofiltrates obtained from dysentery patients (an increase in the level of sIgA has been detected).