Study Finds No Increased Risk for Transplant Patients from Donor Kidneys with Toxoplasma

A recently published study in the journal Transplant International, researchers have found that transplant patients who receive kidneys infected with the parasite toxoplasma have virtually the same outcomes as those who receive toxoplasma-negative organs. Despite longstanding concerns, those who received kidneys from toxoplasma antibody positive donors (TPDs) had almost identical mortality and rejection rates.

Toxoplasma is a ubiquitous parasite that infects many people but generally causes no harm. However, people who are immunosuppressed, such as kidney recipients, could be at higher risk. Toxoplasmosis can be transmitted through the transplanted kidney and reactivate a latent infection in the kidney recipient. Still, there has been tremendous inconsistency in how transplant centres treat TPD kidneys, with some accepting them and others rejecting.

The study analysed 51,000 transplants from the Organ Procurement and Transplantation Network database. Of those, 4,300 were TPD. They found rejection and graft failure was 5% for both TPD and non-TPD kidneys. Other measures were similarly aligned. In other words, the TPD kidneys posed no additional risk.

The two cohorts were comparable in most demographic and Tx characteristics with a few exceptions, as outlined in Table 2. Causes of donor death differed between the two cohorts (p < 0.001), with a disproportionately higher percentage of deaths in the TPD group attributed to stroke/cerebrovascular accident (21.6%) compared to the Toxoplasma-negative group (14.5%), which may be explained by the known association between toxoplasma and stroke . TPD were more likely to be seen in adult Tx recipients (8.5% versus 5.3%, p < 0.0001) and in men (8.7% versus 8.0%, p 0.005).

Based on the study, the largest to date exploring the outcomes of renal Tx recipients categorised by donor Toxoplasma status, it can reasonably recommend that TPD Tx is safe to perform with close monitoring, and that such organs should not be reflexively discarded, with the caveats discussed below. Despite the presence of Toxoplasma in the donor kidneys, the infection does not significantly affect the outcome or safety of the kidney transplant for the recipient.

References: Zhou, AL, Leng, A, Ruck, JM, Akbar, AF, Desai, NM, and King, EA. Kidney Donation After Circulatory Death Using Thoracoabdominal Normothermic Regional Perfusion: The Largest Report of the United States Experience. Transplantation (2023) 108:516–23. doi:10.1097/TP.0000000000004801