Testing the properties of an experimental batch of zoster immune gammaglobulin (ZIG).

The methods of indirct haemagglutination (IH) and precipitation in gel (ID) were employed to test the level of varicella-zoster (VZ) antibodies in an experimental batch of zoster gammaglobulin (ZIG). The titre of indirect haemagglutinating antibodies in ZIG was about 64 times higher than in the ordinary batches of normal immunoglobulin and about 8 times higher in comparison with the level of the initial plasma pool. In the reaction of precipitation in gel, ZIG produced 5 to 6 zones. In comparison with the initial pool of convalescent plasma, ZIG also showed an 8-fold concentration of precipitating antibodies. ZIG was administered preventively to 6 children with risk diagnoses. None of the children fell ill with varicella. According to the results of subsequent serological examination in the reactions of indirect haemagglutination and radioimmunologic analysis, only 3 children were definitely susceptible to VZ infection. In two other children (very low antibody titres) the risk could not be excluded. No substantial increase in the levels of IH and RIA antibodies was observed in the 4 children under serological observation in a period of 6 months following the administration of ZIG. ZIG was administered therapeutically to four children with varicella. The effect of ZIG therapy was very suggestive, especially in two newborn infants lacking maternal antibodies, where the dose of ZIG per 1 kg body weigt was unusually high.