Successful lung transplantation in genetic methionyl-tRNA synthetase-related alveolar proteinosis/lung fibrosis without recurrence under methionine supplementation: Medium-term outcome in 4 cases.

Pulmonary alveolar proteinosis (PAP) results from the accumulation of lipoproteinaceous material in the alveoli and alveolar macrophages, and can be associated with pulmonary fibrosis, with a need for lung transplantation (LTx). Causes of PAP are autoimmune (90%-95%), secondary (5%), or hereditary (<1%). Patients with hereditary PAP are generally not considered for isolated LTx, due to the high probability of recurrence after LTx, and only a challenging scenario with sequential LTx followed by hematopoietic stem cell transplantation (HSCT) was reported as successful. Recently, a new genetic cause of PAP linked to mutations in the methionyl-tRNA synthetase (MARS) gene has been reported, with a highly variable clinical presentation. Because clinical correction of the defective MARS activity with methionine supplementation has been reported in nontransplanted children, we reassessed the feasibility of LTx for candidates with MARS-related PAP/fibrosis. We report 3 cases of LTx performed for MARS-related pulmonary alveolar proteinosis-pulmonary fibrosis without recurrence under methionine supplementation, whereas another fourth case transplanted without supplementation had fatal PAP recurrence. These results suggest the effectiveness of methionine in correcting defective MARS activity and also looking for this very rare diagnosis in case of unclassified PAP/fibrosis. It argues for not excluding the feasibility of isolated LTx in patients with MARS mutation.

A virtual crossmatch-based strategy for perioperative desensitisation in lung transplant recipients with pre-formed donor-specific antibodies: 3-year outcome.

BACKGROUND: Pre-formed donor-specific antibodies (DSAs) are associated with worse outcome after lung transplantation (LTx) and might limit access to LTx. A virtual crossmatch-based strategy for perioperative desensitisation protocol has been used for immunised LTx candidates since 2012 at Foch Hospital (Suresnes, France). We compared the outcome of desensitised LTx candidates with high DSA mean fluorescence intensity and those with low or no pre-formed DSAs, not desensitised. METHODS: For all consecutive LTx recipients (January 2012 to March 2018), freedom from chronic lung allograft dysfunction (CLAD) and graft survival were assessed using Kaplan-Meier analysis and Cox multivariate analysis. RESULTS: We compared outcomes for desensitised patients with high pre-formed DSAs (n=39) and those with no (n=216) or low pre-formed DSAs (n=66). The desensitisation protocol decreased the level of immunodominant DSA (class I/II) at 1, 3 and 6 months post-LTx (p<0.001, p<0.01 and p<0.001, respectively). Freedom from CLAD and graft survival at 3 years was similar in the desensitised group as a whole and other groups. Nevertheless, incidence of CLAD was higher with persistent high-level DSAs than cleared high-level (p=0.044) or no DSAs (p=0.014). Conversely, graft survival was better with cleared high DSAs than persistent high-level, low-level and no pre-formed DSAs (p=0.019, p=0.025 and p=0.044, respectively). On multivariate analysis, graft survival was associated with cleared high DSAs (hazard ratio 0.12, 95% CI 0.02-0.85 versus no DSAs; p=0.035) and CLAD with persistent DSAs (3.04, 1.02-9.17 versus no pre-formed DSAs; p=0.048). CONCLUSION: The desensitisation protocol in LTx recipients with high pre-formed DSAs was associated with satisfactory outcome, with cleared high pre-formed DSAs after desensitisation identified as an independent predictor of graft survival.

Conversion to belatacept after lung transplantation: Report of 10 cases.

BACKGROUND: Calcineurin inhibitors (CNIs) remain the cornerstone of maintenance immunosuppression (IS) after lung transplantation (LTx), although CNI-related life-threatening toxic effects may occur. Belatacept, a novel immunosuppressant that blocks a T-cell co-stimulation pathway, is a non-nephrotoxic drug indicated as an alternative to CNIs in kidney Tx. In LTx, there are only a few reports of belatacept conversion as a CNI-free or CNI-sparing IS treatment. METHODS: We reviewed a series of 10 LTx recipients with conversion to a CNI-free belatacept IS regimen within the first year post-LTx (n = 7) or a belatacept/low-dose CNI combination after the first year (n = 3). RESULTS: Use of belatacept was triggered by severe renal failure in 9 patients and under-IS with previous other IS-related toxicities in 1 patient. Mean estimated glomerular filtration rate after starting belatacept significantly improved at 6 months after initiation and at the last-follow-up (p = 0.006, and p = 0.002 respectively). The incidence of recurrent and/or severe acute cellular rejection (ACR) episodes was high in patients with CNI-free belatacept-based IS (n = 4/7). Chronic graft allograft dysfunction developed in 2 of 9 recipients under belatacept IS. Belatacept was stopped in 6 patients because of recurrent/severe ACR (n = 3), recurrent opportunistic infections (n = 1), center modified policy (n = 1), or other cause (n = 1). CONCLUSION: Early conversion to CNI-free belatacept-based IS improved renal function in this series but was counterbalanced by a high incidence of recurrent ACR, including life-threatening episodes. Other studies are needed to better determine the indications for its use after LTx, possibly with lower immunological risk IS regimens, such as CNI-sparing belatacept.

COVID-19 in Lung Transplant Recipients: 2 Cases With Acute Respiratory Distress Syndrome Successfully Treated With High-Dose Corticosteroids.

Acute respiratory distress syndrome remains the main cause of death among people with COVID-19. Although many immunomodulatory and antiviral drug therapies have been tested, the only effective therapy against severe COVID-19 pneumonia among the general population is a regimen of high-dose corticosteroids for cases of severe associated inflammation. In solid-organ transplant recipients with long-term immunosuppression, data on disease presentation and evolution are scarce, and the benefit of high-dose corticosteroids remains uncertain for cases of severe COVID-19 pneumonia. Here, we report 2 cases of COVID-19-related acute respiratory distress syndrome that occurred in lung transplant recipients in March and April 2020, respectively. Both cases of acute respiratory distress syndrome occurred in patients with long-term azithromycin treatment prescribed to prevent chronic allograft dysfunction. Acute respiratory distress syndrome was associated with severe inflammation and was cured after early administration of high-dose corticosteroids in both cases, with progressive and complete resolution of lung lesions evidenced on thoracic computed tomography scan. Our findings support the benefit of early high-dose corticosteroids in COVID-19-related acute respiratory distress syndrome with hyperinflammation in patients with long-term immunosuppression such as lung transplant recipients.