Vaccination of the immunocompromised child

Treatment and revaccination of children with paraneoplastic opsoclonus-myoclonus-ataxia syndrome and neuroblastoma: The Memorial Sloan Kettering experience

OBJECTIVE

To review the treatment and revaccination of neuroblastoma-associated opsoclonus-myoclonus-ataxia syndrome (OMAS) patients at Memorial Sloan Kettering Cancer Center (MSK).

PROCEDURE

Institutional Review Board approval was obtained for this retrospective study of patients with neuroblastoma-associated OMAS followed at MSK from 2000 to 2016.

RESULTS

Fourteen patients (nine female) were 9-21 (median 17) months old at diagnosis of neuroblastoma and OMAS syndrome. They had stage 1 (n = 12), stage 2B, or intermediate-risk stage 4. Tumor histology was favorable in 11 patients, unfavorable in two, and unknown in one patient. No patient had amplified MYCN. All patients underwent tumor resection at diagnosis. Anti-neuroblastoma treatment was limited to chemotherapy in one patient. Overall survival is 100% at 3-16 (median 10) years. For OMAS, 13 patients received intravenous immune globulin (IVIg), adrenocorticotropic hormone (ACTH), and rituximab, and one received ACTH and IVIg. Seven patients experienced OMAS relapse. For these relapses, five patients received low-dose cyclophosphamide and two received rituximab. The mean total OMAS treatment was 20-96 (median 48) months. Seven patients started rituximab ≤3 months from diagnosis and did not relapse. The other six experienced OMAS relapse. To date, six patients have been revaccinated at a minimum of 2 years after completion of OMAS therapy without OMAS recurrence.

CONCLUSIONS

Patients with neuroblastoma-associated OMAS had excellent overall survival. Early initiation of rituximab, IVIg, and ACTH may reduce risks of OMAS relapse. Revaccination can be resumed without exacerbation of OMAS. Further investigation with a larger cohort of patients is needed.

Protective immunity to Listeria monocytogenes infection mediated by recombinant Listeria innocua harboring the VGC locus

In this study we propose a novel bacterial vaccine strategy where non-pathogenic bacteria are complemented with traits desirable for the induction of protective immunity. To illustrate the proof of principle of this novel vaccination strategy, we use the model organism of intracellular immunity Listeria. We introduced a, low copy number BAC-plasmid harbouring the virulence gene cluster (vgc) of L. monocytogenes (Lm) into the non-pathogenic L. innocua (L.inn) strain and examined for its ability to induce protective cellular immunity. The resulting strain (L.inn::vgc) was attenuated for virulence in vivo and showed a strongly reduced host detrimental inflammatory response compared to Lm. Like Lm, L.inn::vgc induced the production of Type I Interferon's and protection was mediated by Listeria-specific CD8⁺ T cells. Rational vaccine design whereby avirulent strains are equipped with the capabilities to induce protection but lack detrimental inflammatory effects offer great promise towards future studies using non-pathogenic bacteria as vectors for vaccination.

Vaccination of the solid organ transplant recipient

Active immunization is the most important way to protect immunocompromised patients from vaccine-preventable infectious diseases. Although live vaccines are contraindicated for most immunocompromised patients, many inactivated or conjugate vaccines are safe and generally recommended. Some vaccines are known to be of suboptimal immunogenicity in transplant recipients. As a consequence, this may be associated with an impaired ability to mount protective immunity. Nevertheless, even partial protection has been shown to confer significant benefit to this vulnerable patient group. To increase efficacy in generating protective immunity, patients should complete the full complement of recommended vaccinations early in the course of disease before transplantation. This review summarizes the general recommendations for vaccinations of adult transplant recipients and candidates including special considerations for household contacts and health care workers.

Vaccines against intracellular bacterial pathogens

There is a long history of remarkable success in developing vaccines against bacteria that are extracellular pathogens. In general, the development of vaccines against intracellular bacterial pathogens has proven to be more challenging. Typically, such vaccines need to induce a range of immune responses, including antibody, CD4(+) and CD8(+) T cell responses. These responses can be induced by live attenuated vaccines, but eliciting these responses with non-living vaccines has proven to be difficult. The difficulties appear to be related partly to the problems associated with the identification of protective antigens and partly with the difficulties associated with inducing CD8(+) T cell responses.

Update on immunizations in solid organ transplant recipients: what clinicians need to know

Vaccine-preventable diseases remain a major source of morbidity and mortality in transplant recipients. Since the publication of the American Society of Transplantation's guidelines for vaccination of solid organ transplant recipients in 2004 (1), several new vaccines have been licensed. Transplant clinicians have been inundated by questions from patients and colleagues regarding the utility and safety of these vaccines in transplant candidates and recipients. In addition, new data has appeared regarding utility of some established vaccines, lack of rejection after vaccination and newer adjuvant strategies. Literature published between 2004 and 2007 was reviewed in a Medline search. Guidelines from the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices are reviewed and summarized, with particular attention to vaccines for human papillomavirus, varicella and varicella-zoster, tetanus-reduced diphtheria-acellular pertussis (Tdap) and hepatitis B, as well as conjugated meningococcal and conjugated pneumococcal vaccines. Although randomized controlled trials in transplant recipients have not been performed for most new licensed vaccines, preliminary recommendations can be formulated based on current data and guidelines. Further studies will be important to determine the indications and optimal timing of newer immunizations and immunization strategies.

Vaccination for the paediatrician

In most of Australia, general practitioners manage routine childhood vaccination schedules. However, paediatricians have an important role and need to have a thorough understanding of vaccination, particularly as it interfaces with other medical care. This is challenging as the Australian Standard Vaccination Schedule has undergone some substantial changes over the past 4 years, with the addition of meningococcal C conjugate, 7 valent pneumococcal conjugate, varicella and inactivated polio vaccines. Paediatricians are frequently the first port of call for advice on vaccination schedules for children with special needs, in relation to either vaccine efficacy or the risk of side effects. Categories include children with a range of chronic diseases, immunosuppression, premature infants and immigrant children. Advice about specific vaccines such as varicella, inactivated polio, influenza or multivalent vaccines and revaccination after adverse events is also often sought. The aim of this article is to update paediatricians on vaccination recommendations and relevant reference sources. The first part of this article discusses groups with special vaccination requirements. The second part discusses the use of individual vaccines in these children.