Emerging viruses in transplantation

In class we have discussed several pitfalls in transplantation of organs and bone marrow. A classic case was of the boy in the bubble who died from donor derived EBV effects on immunocompromised individuals. This paper describes an increased understanding of other viral infections and their associated risks for transplant patients that would not normally have high rates of morbidity and mortality. Usually, the focus is on CMV and EBV but 12 other viral threats have been described here, some of which I have never heard even heard of. They include Adenovirus, Boca virus, corona virus, HHV-6, lymphocytic choriomeningitis virus, meta pneumovirus, mumps, measles, parainfluenza, Parvovirus B19, respiratory syncytial virus, rotavirus and west nile virus. Some of these are donor derived and some are community derived. All of these can be detected and characterized easily with advanced techniques such as PCR on easily obtained patient samples such as sputum and nasopharangeal washes. Not long ago the diagnosis was limited in specificity and was performed using primarily serology and histochemical techniques. As solid organ and stem cell/ bone marrow transplants are on the rise as effective therapies, it is important to use the techniques available to increase the longevity and quality of life for these patients. Examples of increased morbidity and mortality due to these viruses were discussed in this paper. Adenovirus can cause many types of infection including that of the respiratory tract. In healthy people, a 5-10% mortality rate can be seen with some infections. In transplant recipients, some adenovirus diseases have mortality rates of up to 80% and can occur up to 4 years after transplantation. Some manifestations are asymptomatic and affect many tissues and cell types. After detection, antivirals and intravenous Ig (IVIg) have been associated with positive outcomes.
HHV-6 is another common virus and is latent in ~90% of adults in immune, salivary and bronchial epithelial cells. Immunocompromised individuals reactivate with replication in CD4+ cells further suppressing the patient immune response ultimately leading to high mortality rates of up to 58%. Once detected as an active infection, antivirals have been seen to be effective treatments. Mumps and measles have a slightly different approach to deal with in immunocompromised patients as there are no specific antiviral treatments. It is recommended to vaccinate for example, stem cell transplant patients 2 years after the transplant. However, this leaves a small gap in time where people are susceptible with high attack rates and associated high mortality rates. The evaluation of viral infection, diagnosis and treatment continue in this paper but all remain serious threats and deserve attention as they can be major factor in increasing the longevity of transplant patients.

Emerging Viruses in Transplantation: There Is More to Infection After Transplant Than CMV and EBV.
Transplantation. 86(10):1327-1339, November 27, 2008.
Fischer, Staci A.