Toshikazu Watanabe

Lung transplant (LTx) recipients face a significant risk from coronavirus disease 2019 (COVID-19), with elevated hospitalization mortality rates even post-vaccination. While severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) typically induces pneumonia in even healthy individuals, it can also infect the transplanted lungs of LTx recipients, potentially leading to graft dysfunction. Despite the prevalence of COVID-19 pneumonia in LTx recipients, data on its characteristics and associated risk factors remain limited. This retrospective study analyzed data from LTx recipients at Tohoku University Hospital between January 2001 and November 2023. COVID-19 cases were identified, and patient records, including thoracic computed tomography (CT) evaluations, were reviewed. Patient characteristics, vaccination history, immunosuppressant use, and comorbidities were assessed. Descriptive analysis was utilized for data presentation. Among 172 LTx recipients, 39 (22.7%) contracted COVID-19, with 9 (23%) developing COVID-19 pneumonia. COVID-19 incidence in LTx recipients aligned with national rates, but pneumonia risk was elevated. Delayed antiviral therapy initiation was noted in pneumonia cases. Remdesivir was uniformly administered and remained the primary treatment choice. LTx recipients are susceptible to COVID-19 pneumonia, warranting vigilance and tailored management strategies. Pre-transplant vaccination and prompt COVID-19 diagnosis and treatment are imperative for optimizing outcomes in this population.

BACKGROUND: Interstitial lung disease (ILD) represents a heterogeneous group of lung disorders characterized by fibrotic lung tissue changes. In regions with severe donor shortages, single-lung transplantation (SLTx) is often preferred over bilateral lung transplantation for advanced ILD. However, temporal changes and complications in the retained native lung remain poorly understood. METHODS: A retrospective analysis of 149 recipients who had undergone SLTx was conducted, including 34 ILD SLTx recipients. Native-lung volume, radiological alterations, and perfusion were assessed at distinct post-SLTx time points. Statistical analyses compared ILD and non-ILD SLTx groups. RESULTS: Our study revealed a progressive reduction in native-lung volume over time, accompanied by radiographic deterioration and declining perfusion. Complications in the retained native lung were observed, such as pneumothorax (29.4%), pulmonary aspergillosis (11.8%), and acute exacerbation (8.9%). Long-term survival rates were similar between ILD and non-ILD SLTx recipients. CONCLUSIONS: This study illuminates the unique challenges and complications with respect to the native lung following SLTx for ILD. Ongoing monitoring and tailored management are essential. Despite limitations, this research contributes to our understanding of the temporal progression of native-lung complications post-SLTx for ILD, underscoring the need for further investigation.

Letermovir, initially approved for cytomegalovirus (CMV) prophylaxis in hematopoietic stem-cell transplantation, has gained attention for off-label use in lung-transplant (LTx) recipients. Given the high susceptibility of LTx recipients to CMV infection, this study explores the effectiveness and safety of letermovir prophylaxis. A retrospective analysis of using letermovir for LTx recipients at Tohoku University Hospital (January 2000 to November 2023) was conducted. Case summaries from other Japanese transplant centers and a literature review were included. Six cases at Tohoku University Hospital and one at Kyoto University Hospital were identified. Prophylactic letermovir use showed positive outcomes in managing myelosuppression and preventing CMV replication. The literature review supported the safety of letermovir in high-risk LTx recipients. Despite limited reports, our findings suggest letermovir's potential as prophylaxis for LTx recipients intolerant to valganciclovir. Safety, especially in managing myelosuppression, positions letermovir as a promising option. However, careful consideration is important in judiciously integrating letermovir into the treatment protocol.

BACKGROUND: Analyzing HLA polymorphism in lung transplantation (LTx) is important, given its impact on LTx recipient survival and graft function. Accordingly, we conducted a retrospective study to examine the influence of HLA mismatch and donor-specific antibodies (DSA) on short-term outcomes and early-phase post-LTx complications. METHOD: HLA antigen or eplet mismatch in LTx patients at Tohoku University Hospital from 2018 to 2023 was determined, and DSA was measured on admission for surgery to identify preformed DSA and at weeks 4 to 12 post-LTx for de novo DSA, respectively. RESULTS: The participants were 45 LTx recipients, HLA-A/B/DR antigen mismatch (5-6 of 6) being identified in 57%, HLA-A/B/Cw/DR/DQ mismatch (8-10 of 10) in 57%, and HLA eplet mismatch (>61) in 46%. The prevalence of preformed DSA was 24%, and persistence (uncleared) was 16%. The incidence of de novo DSA was 16% after LTx. During the study,16 recipients experienced grade 3 primary graft dysfunction (PGD), 8 developed acute rejection, and 5 died. No HLA-related variables were significantly associated with post-LTx mortality and were not risk factors for high-grade PGD or acute rejection. CONCLUSION: Despite limitations in sample size, resulting in tentative findings, the study serves as a crucial pilot study for an ongoing multicenter prospective trial in Japan.