Antibody prophylaxis of varicella in immunosuppressed patients.

ZIG prophylaxis was administered to a total of 39 children immunosuppressed under antitumour therapy and presenting a negative varicella history. Varicella developed in only 2 of them. 47 children received a substitutive prophylaxis consisting of ordinary gammaglobulin NORGA. Fourteen of the children fell ill with varicella, two of the cases being complicated. With a few exceptions, the cases represented hospital contacts, because most children with anticancer therapy are in hospital. The difference between the numbers of varicella cases after ZIG and after NORGA was statistically highly significant in the group of seronegative children. On the other hand, the difference between the numbers of cases among preprophylactically seropositive children in both prophylactic groups was not substantial. Varicella was not encountered either among children with a titre of minimally 1:128 at the time of contact with the disease. In contrast, varicella developed in 20-30% of children with a titre of at most 1:64. Four children were serologically followed up for 35-49 days after the injection of ZIG. The degradation of VZV antibodies in these children under immunosuppression was far more rapide than that of known passively transferred IgG in normal individuals. In states of deep immunosuppression a quantitatively or qualitatively different mechanism of passively transferred antibody clearance is probably involved.