Transplant recipients are at extremely high risk of infectious complications because of their immune-compromised state. These patients tolerate infection poorly with high morbidity and mortality. Dr Vikas Jain, Assistant Professor & Head, Renal Transplant and Urology, Institute of Liver and Biliary Sciences, in conversation with Shahid Akhter, ENN discusses the issues in management of infectious complications after renal transplant.
Transplantation of organs and tissues is increasing. How do you identify and eliminate donor derived infections that come with risks associated with transplantation? How stringent are the screenings? Infections derived from donor tissues are the most important exposures in renal transplantation. Some of these are latent infections, such as tuberculosis, which may become activated many years after the exposure, whereas others are the result of the occurrence of active infection in the donor at the time of procurement. Living donors undergo an extensive screening program to prevent transmission of such infections to the recipient however donor screening is limited by the time available within which the organs from brain-dead donors must be used. It is reasonable to avoid donation from individuals with unexplained fever, rash, or infectious syndromes, in this setting.
Once the tissues or organs have been harvested and stored, how do you ensure that they remain free from any infection during storage?
Living donation is the major source of organs in India. Storage and transmission of infection during this stage is never an issue in living donation, as the organ is transplanted immediately after harvesting. The safe storage is an issue in organs harvested from deceased donors. An easy and convenient way is to cool the organ. Most commonly used now a days is the static cold storage technique, which includes a rapid vascular flush and washout with removal of blood with subsequent storage in a preservation solution at 0 to 40C. This
procedure virtually eliminates of risk of infection during storage.
Cytomegalovirus (CMV) is the single most important infectious agent affecting recipients of organ transplants, with at least two-thirds of these patients having CMV infection 1–4 months after transplantation. Please comment on the Indian scenario.
Screening for CMV is an integral part of donor evaluation as CMV greatly impacts the course of renal transplant recipient. Transmission of CMV in the transplant recipient depends on the CMV serostatus of the recipient and donor at the time of the transplantation.
Seronegative recipients who receive organs from seropositive donors (D+/R–) have a 40–50% chance of developing the disease. Endogenous reactivation leading to CMV disease occurs in 10–15% of seropositive recipients (D+/–R+). The figure may be higher in those who receive anti-lymphocyte therapy. The risk is negligible in D–R– transplants. As for as Indian scenario is concerned, I would like to quote the paper from CMC Vellore published in Journal of Nephrology and Renal Transplantation in 2009. In their series, more than 90% of patients and donors tested,were found to be infected with cytomegalovirus (CMV). CMV disease occurred in 20% of patients, and 6% have tissue-invasive disease, mostly of the gut and the lungs, causing considerable morbidity and mortality.
Viral, bacterial, and fungal infections have been transmitted via transplantation of organs and tissue allografts. What preventive measures are used to keep such infections at bay?
Transplant recipient can contract four different types of infections– donor-derived infections, recipient-derived infections, community-derived exposures, and nosocomial exposures. Extensive screening protocols are in place to prevent the transmission of donor-derived and recipient-derived infections. In living donor transplants, a complete detailed evaluation is possible and all the infections are treated before the surgery. The crucial feature in screening of deceased donors is time limitation. However, all the efforts are made to complete all the microbiologic assessments. Major infections are excluded, and appropriate cultures and samples are obtained for future reference. Such strategies have significantly reduced the risk of transmission of infection but the incidence is still not zero. In addition, majority of post-transplant protocols include routine prophylaxis against various infections for e.g. trimethoprim/ sulfamethoxazole for Pneumocystis carinii and antifungals.
Several types of protozoan and even worm parasites have been transferred via organ transplants. How do you address this issue?
Parasitic infections are usually recipient derived exposures or community derived exposures. They are rarely transmitted during transplants. These include foodborne and waterborne infections. Dietary habits, including use of boiled water and hygienic freshly cooked food and some other lifestyle changes play a major role in the prevention of this category of infections.
The main issue in the management of infectious complications after transplant is diagnostic dilemma, as patients manifest diminished signs and symptoms of infections and they may develop systemic signs in response to noninfectious processes like rejection
Organs cannot be subjected to sterilization process. How do you eliminate or minimize the risk of infectious disease transmission?
It is true that organs cannot be subjected to various sterilization process but they still remain sterile because they are harvested in a sterile fashion, stored in a sterile preservation solution and then transplanted in a sterile manner. Strict sterility is maintained at each step and by every individual involved in the transplantation. This makes a sort of sterile “chain” and there is actually no need to sterilize the organ.