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Antibody prophylaxis of varicella in immunosuppressed patients
J Trlifajová1, V Smelhaus, E Svandová
1Institute of Hygiene, and Epidemiology, Prague, Czechoslovakia.
Insights
Zoster immune globulin (ZIG) significantly reduced varicella (chickenpox) incidence in immunosuppressed children compared to normal gammaglobulin. Antibody levels declined rapidly in these patients, suggesting altered clearance mechanisms.
Area of Science:
- Pediatric Oncology
- Immunology
- Infectious Diseases
Background:
- Immunosuppressed children undergoing anticancer therapy are at high risk for severe varicella (chickenpox).
- Prophylaxis is crucial to prevent varicella infection and complications in this vulnerable population.
Purpose of the Study:
- To evaluate the efficacy of zoster immune globulin (ZIG) compared to normal gammaglobulin (NORGA) for varicella prophylaxis in immunosuppressed children.
- To investigate the antibody kinetics and clearance mechanisms of passively transferred antibodies in this patient group.
Main Methods:
- A comparative study involving 39 children receiving ZIG and 47 children receiving NORGA for varicella prophylaxis.
- Varicella incidence and complications were recorded.
- Serological follow-up was conducted in a subset of children to assess antibody levels and degradation rates.
Main Results:
- ZIG prophylaxis resulted in a statistically significant reduction in varicella cases compared to NORGA in seronegative children.
- No substantial difference in varicella incidence was observed between ZIG and NORGA in seropositive children.
- Varicella was prevented in children with pre-existing VZV antibody titers of 1:128 or higher.
- Rapid degradation of VZV antibodies was observed in immunosuppressed children post-ZIG, differing from normal individuals.
Conclusions:
- ZIG is a highly effective prophylaxis against varicella in immunosuppressed children with no prior history of the disease.
- Antibody clearance in deeply immunosuppressed children may involve different mechanisms than in immunocompetent individuals.
- Maintaining adequate antibody titers is crucial for preventing varicella in at-risk pediatric populations.
Abstract:
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.