Varicella and zoster in children after kidney transplantation: long-term results of vaccination

Response to varicella immunization in pediatric liver transplant recipients

BACKGROUND

Individuals undergoing therapeutic immunosuppression are at risk of severe varicella-zoster virus (VZV) infection, particularly those without evidence of previous infection.

METHODS

Eleven children, median age 10 months (range 5.5 months to 7 years and 9 months) received one dose of varicella vaccine (Varilrix, SmithKline Beecham plc, UK) before liver transplantation (median interval 95 days, range 40-289 days). The serological response to varicella vaccine was evaluated retrospectively and matched with the outcome and management of any subsequent exposures to VZV.

RESULTS

Three children responded postimmunization, six children showed no response, and in two children the outcome was difficult to interpret having received blood products. Four children required varicella-zoster immunoglobulin prophylaxis posttransplantation, two of whom developed mild chickenpox.

CONCLUSIONS

Only 3 of 11 children developed a clear antibody response to varicella vaccine. Administration of varicella vaccine did not affect the management of subsequent VZV exposures.

Progress in renal transplantation for children

Renal transplantation continues to be the goal of therapy for children with end-stage renal disease. Patient age, primary renal disease, psychosocial status, living versus cadaver donor allograft, immunosuppressive therapy, urologic status, and maximization of growth and development must be considered in determining the optimal time for transplantation. Immunizations should be up to date, and the immune status of both the donor and the recipient with regard to Epstein Barr virus (EBV), cytomegalovirus (CMV), varicella, human immunodeficiency virus (HIV) and Hepatitis A, B, and C must be known. Prednisone; cyclosporine or tacrolimus; and mycophenolate mofetil or azathioprine remain the mainstays of immunosuppression. However, new therapies such as sirolimus are under investigation for use in pediatric renal transplantation. Induction therapies include T-cell antibodies as well as the more recent addition of interleukin-2 receptor blockers. Complications including infection, rejection, and malignancy continue to be problematic in pediatric renal transplantation. There continues to be a strong focus on optimizing growth and development after transplant. Although patient and graft survival have improved over time, outcomes in pediatric renal transplantation continue to lag behind those in adults.

Immunisation against varicella in end stage and pre-end stage renal failure. Trans-Pennine Paediatric Nephrology Study Group

OBJECTIVES

To investigate the seroconversion rate and duration of persistence of protective antibody titres after varicella immunisation in children with renal failure.

DESIGN

32 children (25 end stage and 7 pre-end stage renal failure) were immunised using 2 x 2,000 plaque forming unit doses of varicella vaccine 3 months apart. Varicella antibody titres were measured by enzyme linked immunosorbent assay.

RESULTS

All children initially seroconverted after immunisation. At a mean follow up of 20.3 months, 23 of 28 had protective antibody titres, 4 children having died of unrelated causes. Two children required a third booster dose. 11 children underwent renal transplantation; 10 had protective titres at the time of transplantation and, at a mean of 23.4 months after immunisation, 6 currently have protective titres. Minor side effects occurred after 11 vaccine doses in 9 children. No child developed varicella, despite 10 clear episodes of exposure to the wild-type virus.

CONCLUSIONS

Varicella immunisation in children with end stage and pre-end stage renal failure results in a high rate of seroconversion and persistence of protective antibody titres. More widespread use of the vaccine before renal transplantation is recommended.

Disseminated varicella infection in pediatric renal transplant recipients treated with mycophenolate mofetil

BACKGROUND

Mycophenolate mofetil (MMF) is a new immune suppressive agent, effective in the prevention of acute rejection after renal transplantation.

METHODS

The study was a retrospective review of records of pediatric renal transplant recipients from 1985 to the present.

RESULTS

Since October 1995, the immune suppression protocol for pediatric renal transplant recipients at Mayo Eugenio Litta Children's Hospital has included MMF, prednisone, and cyclosporine A. During that time, 19 children and adolescents have received renal allografts, 17 of whom were seropositive for varicella antibody before transplantation, while 2 were seronegative. Varicella infection occurred in 3 of 19 patients (15.8%), all 3 of whom had serologically documented immunity to varicella virus before transplantation. All episodes occurred within 12 months of transplantation. All had generalized vesicular lesions without dermatomal distribution. None of the patients developed fever, respiratory, mucocutaneous, or central nervous system manifestations. All were managed with oral acyclovir, and had an uncomplicated recovery without neuralgia. By contrast, of 74 consecutive patients transplanted before use of MMF, only 1 patient (1.4%) had varicella infection after transplantation (P=0.026).

CONCLUSION

The enhanced immunosuppression achieved with MMF appears to be associated with increased susceptibility to varicella infection.