Donor-derived infection--the challenge for transplant safety

Abstract

Organ transplantation, including of the heart, lung, kidney, liver, pancreas, and small bowel, is considered the therapy of choice for end-stage organ failure. Each year, over 70,000 organs are implanted worldwide. One donor may provide multiple organs, as well as corneas and other tissues, for multiple recipients. The degree of risk for transmission of infection carried with grafts, notably of viruses, is largely unknown and, for a specific organ, difficult to assess. The approach to microbiological screening of organ donors varies with national and regional regulations and with the availability and performance of microbiological assays used for potential donors. Transmission of both expected or common, and unexpected infections has been observed in organ transplants, generally recognized after development of clusters of infections among recipients of organs from a common donor. Other than for unusual or catastrophic events, few data exist that define the incidence and manifestations of donor-derived infections or the ideal assays to use in screening to prevent such transmissions. Absolute prevention of the transmission of donor-derived infections in organ transplantation is not possible. However, improvements in screening technologies will enhance the safety of transplantation in the future.

Figure 1. The 'window period' in microbiological screening of potential organ donors.

The development of an antibody response against a pathogen requires weeks to months after the initial infectious exposure. The time between the infectious exposure and the development of antibodies that can be detected by microbiological assays is called the window period. Serologic testing during this period might result in false-negative results. NAT measures viral nucleic acids, often using signal amplification techniques. Depending on the performance characteristics of the assay and the amount of virus present in the clinical specimen, NAT tends to detect infection earlier and with greater sensitivity than the corresponding serologic test. However, false-positive assays are generally more common with NAT testing. Abbreviation: NAT, nucleic acid test. PowerPoint slide