Spleen and Immune System
Immune System
For most cancers, the main period of immune suppression is during or immediately following chemotherapy and/or radiation therapy when neutropenia and mucosal injury may be present.
After therapy, there is some evidence that the immune system of some survivors of childhood leukemia and lymphoma never completely recovers. Radiation therapy (RT) and chemotherapy can cause mutations and cytogenetic abnormalities and induce genomic instability.
Specific malignancies, particularly Hodgkin lymphoma and to a lesser degree, non-Hodgkin lymphomas are associated with significant deficits in cell-mediated immunity, which can persist after the completion of therapy.
Other malignancies such as multiple myeloma and B-cell chronic lymphocytic leukemia are associated with deficiencies in humoral immunity and susceptibility, particularly to infection with encapsulated bacteria.
In survivors of childhood leukemia, innate immunity, thymopoiesis, and DNA damage responses to radiation have been shown to be abnormal7, 8
These defects may contribute to their increased likelihood of second malignancy.
BMT and Immune status:
Immune status is also compromised after stem cell transplantation, particularly in association with graft-versus-host disease10
The functional recovery of humoral and cellular immunity may take more than a year after BMT. This will depend on:
- Type of graft used (autologous or allogeneic)
- Type of immunosuppressive therapy used after transplant
- If cGvHD is present
Delayed overall immunologic reconstitution leads to an increased risk of infection for at least a year or so after transplant.
Prophylaxis for P. carinii infection is usually given for a year or so after BMT
Vaccinations are usually recommended at the end of one yearafter HSCT, if NO GVHD give :
- Influenza yearly
- Pneumococcal vaccine
- DPT (Diptheria-Pertussis-Tetanus)
- Inactivated polio virus
Immunosuppressed patients with GVHD are unlikely to develop an adequate antibody response after vaccination.
A few patients who are 2 years post-transplant may benefit from MMR live vaccines. They should have no evidence of GVHD and not taking immunosuppressant medication.
Children off therapy for Acute Leukemia:
Antibody levels to previous vaccinations are also reduced in patients off therapy for ALL for at least one year suggesting persistence of abnormal humoral immunity8, 9
Such children are very likely to need revaccination. At end of treatment all patients should have their titers checked for (+/- re-immunized for) :
- Polio
- Tetanus
- Measles
- Mumps
- Rubella
- HSV
- VZV
- Hepatitis B
Link to resource for vaccine information in general and in oncology patients:
BC Center for Disease Control: Immunization Manual
