# Impact of immunosuppressive therapy on pulmonary perfusion in kidney transplant recipients after COVID-19 illness

## TL;DR

This study examines how adjusting immunosuppressive therapy affects lung perfusion in kidney transplant recipients who had COVID-19.

## Contribution

The study shows that mTOR inhibitors may improve lung perfusion in kidney transplant recipients after COVID-19.

## Key findings

- mTORi use was linked to increased lung perfusion in all lung segments.
- Pulmonary perfusion improvements were observed six months after treatment.
- Adjusting immunosuppressive therapy may benefit respiratory outcomes in these patients.

## Abstract

Patients who have received kidney transplants (KTR) are considered to be more susceptible to the severity of COVID-19-related illness. The transplanted patient’s respiratory outcome worsened because of the ventilation-perfusion mismatch that occurs during the infection, which has been linked to endothelial damage. In this context, a reduction in immunosuppressive therapy is advisable to improve patient outcomes. However, the prognosis and suggested treatment for these types of patients are still debated.

We retrospectively analyzed 48 KTRs with stable graft function on calcineurin inhibitor therapy who underwent transient modification of the maintenance immunosuppressive regimen with withdrawal of mycophenolic acid/mycophenolate mofetil or mTOR inhibitor (mTORi) during COVID-19 infection and their reintroduction after healing. Pulmonary functional tests (EGA and spirometry) and DECT (Dual-energy CT) scans were performed 1 month following the negative nasopharyngeal swab (T0) and then after 6 months (T6).

The presence an mTOR inhibitor in immunosuppressive therapy was associated with a significant increase in lung perfusion for the entire lung parenchyma of the mTORi-treated group, both in each lung segment considered separately and all of them together.

Our findings are consistent with the observation that the use of mTORi could play a potentially beneficial role in improving pulmonary perfusion.