The fraction of sensitization among lung transplant recipients in a transplant center in Japan

Key predictors of long-term survival after lung transplantation in Japan

BACKGROUND

Lung transplantation (LTx) is essential for treating end-stage lung diseases in Japan, achieving favorable long-term survival despite donor shortages. However, factors associated with long-term survival after transplantation remain unclear. This study aims to identify key predictors influencing post-transplant outcomes.

METHODS

A retrospective analysis was conducted on LTx recipients at Tohoku University Hospital from 2000 to 2019, with a follow-up period of five years to 2024. Recipients were categorized into short survivors (<5 years) and long survivors (≥5 years). The analysis focused on recipient demographics, donor characteristics, surgical factors, and post-transplant outcomes.

RESULTS

Of 124 recipients, 36 were short survivors, and 88 were long survivors. Long-term survivors were younger, with a lower prevalence of patients aged 55 years and older. Additionally, fewer long-term survivors received lungs from critically marginal donors compared to short-term survivors. CMV serology was a significant factor, with a higher incidence of CMV disease observed in short-term survivors.

CONCLUSION

The study identified younger age, selective donor use, and CMV status as key predictors associated with long-term survival after LTx in Japan. The findings underscore the importance of targeted CMV management strategies and suggest that future multicenter studies with larger, more diverse populations are needed to confirm these results and further enhance long-term survival outcomes.

Long-term survival and clinical outcomes of delayed chest closure following lung transplantation

PURPOSES

Delayed chest closure (DCC) is a widely accepted procedure in the context of lung transplantation (LTx); yet there are few reports detailing its long-term survival and clinical outcomes.

METHODS

We reviewed the medical records of recipients who underwent deceased-donor lung transplantation (LTx) at Tohoku University Hospital. Long-term survival, including overall survival, freedom from chronic lung allograft dysfunction (CLAD), and CLAD-free survival and the clinical outcomes of graft function and physical performance and constitution were reviewed in recipients with DCC.

RESULTS

Between 2009 and 2022, 116 patients underwent LTx, 33 of whom (28.4%) required DCC. The intra-and post-operative courses of the recipients who required DCC were more complicated than those of the recipients who underwent primary chest closure (PCC), with frequent volume reduction surgery and longer periods of invasive mechanical ventilation. Pulmonary vascular disease was considered a risk factor for these complications and DCC. Nonetheless, long-term survival and graft functions were comparable between the DCC and PCC groups. The physical performance and constitution of recipients who required DCC continued to improve, and by 2 years after transplantation, exhibited almost no difference from those who underwent PCC.

CONCLUSIONS

In view of the profoundly complicated intra- and post-operative courses, DCC should be performed cautiously and only when clinically indicated, despite which it can result in equivalent long-term survival and acceptable outcomes to PCC.

Thoracic and vertebral deformities in lung transplantation: perioperative complications and long-term prognoses

BACKGROUND

Lung transplantation (LTx) is a crucial therapeutic strategy for patients suffering from end-stage respiratory diseases, necessitating precise donor-recipient size matching to ensure optimal graft function. While standard allocation protocols rely on predicted lung capacity based on factors such as sex, age, and height, a subset of patients with respiratory diseases presents an additional challenge - thoracic or vertebral deformities. These deformities can complicate accurate volume predictions and may impact the success of lung transplantation.

METHODS

In this retrospective cohort study of patients who underwent LTx at Tohoku University Hospital between January 2007 and April 2022, with follow-up until October 2022, the primary objective was to assess the influence of thoracic and vertebral deformities on perioperative complications, emphasizing interventions, such as volume reduction surgery. The secondary objective aimed to identify any noticeable impact on long-term prognoses in recipients with these deformities.

RESULTS

Of 129 LTx recipients analyzed, 17.8% exhibited thoracic deformities, characterized by pectus excavatum, while 16.3% had vertebral deformities. Perioperative complications, requiring delayed chest closure, tracheostomy, and volume reduction surgery, were more prevalent in the deformity group. Thoracic deformities were notably associated with the need for volume reduction surgery. However, long-term prognoses did not differ significantly between patients with deformities and those without. Vertebral deformities did not appear to significantly impact perioperative or long-term outcomes.

CONCLUSIONS

This study highlights the prevalence of thoracic deformities in LTx recipients, correlating with increased perioperative complications, particularly the potential need for volume reduction surgery. Importantly, these deformities do not exert a significant impact on long-term prognoses. Additionally, patients with vertebral deformities, such as scoliosis and kyphosis, appear to be manageable in the context of LTx.

COVID-19 pneumonia in lung transplant recipients: understanding risk factors and treatment outcomes in Japan

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.

Single lung transplantation using a lung graft from a donor whose contralateral lung is not suitable for lung transplantation

OBJECTIVE

This study aims to compare the post-transplant survival of untwinned single lung transplantation (SLT) to twinned SLT. In untwinned SLT, the contralateral lung is judged unsuitable for transplantation and might affect the lung graft within the donor body and recipient survival after SLT.

METHODS

A retrospective analysis was conducted on 84 SLT recipients at our center, divided into untwinned SLT and twinned SLT groups. The demographics of donors and recipients, surgical characteristics, complications, mortality, and survival rates were compared.

RESULTS

There were no significant differences in recipient and donor demographics between the two groups. Surgical characteristics showed no significant differences. Microbiological findings of the transplanted lungs indicated a low incidence of positive cultures in both groups. 3-month to 1-year mortality and overall survival rates were comparable between the two groups.

CONCLUSION

At our institution, both untwinned and twinned SLT procedures exhibited excellent survival rates without significant differences between the two procedures. The favorable outcomes observed may be associated with the strategic advantages of Japan's MC system and the diligent management of marginal donor lungs although this requires further investigation to elucidate the specific contributory factors.

Native-lung complications following single-lung transplantation for interstitial lung disease: an in-depth analysis

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 prophylaxis for cytomegalovirus in lung-transplant recipients: a comprehensive study with literature review of off-label use and real-world experiences

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.

A Single-Center Analysis of How HLA Mismatch and Donor-Specific Antibodies Affect Short-Term Outcome After Lung Transplantation: A Pilot Study Before a Country-Wide Histocompatibility Study in Japan

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.

Roles of respirologists in lung transplantation in Japan: narrative review

Background and Objective

Lung transplantation (LTx) in Japan has taken steps toward increasing the number of donors and recipients and is at the maturity stage of development, at which point pulmonologists (hereinafter referred to as "respirologists") become involved in transplant practice. Because of severe donor shortage and limited number of LTx surgeries, most of transplant process from candidacy evaluation to post-operative management has been handled only by thoracic surgeons, which takes away opportunities from respirologists to manage LTx recipients. Given the growth of both LTx and the number of patients with complex problems, cooperation with respirologists in transplant practice is urgently needed to achieve transplant success in Japan.

Methods

Authors summarized current transplant circumstance in Japan from the transplant physician's standpoint. A systematic search through PubMed database and Google Scholar was performed by terms of "respirologists", "pulmonologist", "lung transplant" or "Japan" from 2000 and 2022. Thoracic surgeons working at each transplant center were asked to complete a questionnaire on physicians' intervention to LTx.

Key Content and Findings

The roles of respirologists in LTx differ with facility size and function, depending on whether they are working at a non-transplant center with other respirologists or at a transplant center with transplant physicians. LTx centers are currently devoted to educating respirologists who work at non-transplant or low-volume transplant centers in order for them to deal with patients before and after transplantation.

Conclusions

Joint efforts and training of outstanding personnel who can take care of recipients are required, this being the greatest issue for the success of transplantation in Japan.

Cellular and humoral immune responses after a third dose of SARS-CoV-2 mRNA vaccine in lung transplant recipients in Japan

BACKGROUND

Lung transplant (LTx) recipients are at higher risk of infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). There is an increasing demand for additional analysis regarding the efficacy and safety of after the initial series of mRNA SARS-CoV-2 vaccines in Japanese transplant recipients.

METHOD

In this open-label, nonrandomized prospective study carried out at Tohoku University Hospital, Sendai, Japan, LTx recipients and controls received third doses of either the BNT162b2 or the mRNA-1273 vaccine, and the cellular and humoral immune responses were analyzed.

RESULTS

A cohort of 39 LTx recipients and 38 controls participated in the study. The third dose of SARS-CoV-2 vaccine promoted much greater humoral responses at 53.9 % of LTx recipients than after the initial series at 28.2 % of patients without increasing the risk of adverse events. However, still fewer LTx recipients responded to the SARS-CoV-2 spike protein with the median IgG titer of 129.8 AU/mL and with the median IFN-γ level of 0.01 IU/mL when compared to controls with those of 7394 AU/mL and 0.70 IU/mL, respectively.

CONCLUSION

Although the third dose of mRNA vaccine in LTx recipients was effective and safe, impaired cellular and humoral responses to SARS-CoV-2 spike protein were noted. Given lower antibody production and establishing vaccine safety, repeating the administration of mRNA vaccine will lead to robust protection in such a high-risk population (jRCT1021210009).

Assessment of Anti-Human Leukocyte Antigen (HLA)-Antibody-Dependent Humoral Response in Patients before and after Lung Transplantation

Background and Objectives: Testing for anti-human leukocyte antigen (HLA) antibodies both before and after transplantation is of fundamental significance for the success of lung transplantation. The aim of this study was the evaluation of anti-HLA immunization of patients before and after lung transplant who were subjected to qualification and transplantation. Materials and Methods: Prior to the transplantation, patients were examined for the presence of IgG class anti-HLA antibodies (anti-human leukocyte antigen), the so-called panel-reactive antibodies (PRA), using the flow cytometry method. After the transplantation, the class and specificity of anti-HLA antibodies (also IgG) were determined using Luminex. Results: In the group examined, the PRA results ranged from 0.1% to 66.4%. Low (30%) and average (30-80%) immunization was found in only 9.7% of the group examined. Presence of class I anti-HLA antibodies with MFI (mean fluorescence intensity) greater than 1000 was found in 42.7% of the patients examined, while class II anti-HLA antibodies were found in 38.4%. Immunization levels before and after the transplantation were compared. In 10.87% of patients, DSA antibodies (donor-specific antibodies) with MFI of over 1000 were found. Conclusions: It seems that it is possible to confirm the correlation between pre- and post-transplantation immunization with the use of the two presented methods of determining IgG class anti-HLA antibodies by increasing the size of the group studied and conducting a long-term observation thereof.

Efficacy and safety of mRNA SARS-CoV-2 vaccines in lung transplant recipients

BACKGROUND

To date, reports addressing the antibody response following mRNA SARS-CoV-2 vaccination in lung transplant (LTX) recipients are limited. Thus, the aim of this clinical study was to investigate the efficacy and safety of the vaccines in LTX recipients compared to controls.

METHODS

An open-label, nonrandomized prospective study was conducted at Tohoku University Hospital. LTX recipients and controls who received either the BNT162b2 vaccine or the mRNA-1273 vaccine were recruited, and SARS-CoV-2 IgG was measured before and after vaccination. The adverse events were reviewed. Predictors of negative serology after vaccination were evaluated with logistic regression.

RESULTS

Forty-one LTX recipients and 24 controls were analyzed. Although all controls had a positive antibody response to a SARS-CoV-2 mRNA vaccine, antibody response was found in 24.4% of LTX recipients (p < .0001). The amount of SARS-CoV-2 IgG following the 2nd dose significantly climbed to 6557 AU/mL in controls, whereas the increase in IgG in LTX recipients was 8.3 AU/mL (p < .0001). Fewer LTX recipients developed systemic fever than controls (p < .0001) despite equivalent overall adverse event percentages in both groups. A higher plasma concentration of mycophenolate was a significant predictor of negative serology (p = .032).

CONCLUSIONS

An impaired antibody response to mRNA vaccines was significantly found in LTX recipients compared to controls and was associated with the plasma concentration of mycophenolate. While repeating mRNA vaccination may be one of the strategies to improve antibody response given the safety of the vaccines, emerging data on humoral immune responses based on immunosuppression regimens in LTX recipients should be studied (jRCT1021210009).

Outcome and prognostic factors after lung transplantation for bronchiectasis other than cystic fibrosis

BACKGROUND

While lung transplant (LTX) can be an effective therapy to provide the survival benefit in selected populations, post-transplant outcome in LTX recipients with bronchiectasis other than cystic fibrosis (CF) has been less studied. Pseudomonas aeruginosa, often associated with exacerbations in bronchiectasis, is the most common micro-organism isolated from LTX recipients. We aimed to see the outcomes of patients with bronchiectasis other than CF after LTX and seek the risk factors associated with pre- and post-transplant Pseudomonas status.

METHODS

Patients who underwent LTX at Tohoku University Hospital between January 2000 and December 2020 were consecutively included into the retrospective cohort study. Pre- and post-transplant prevalence of Pseudomonas colonization between bronchiectasis and other diseases was reviewed. Post-transplant outcomes (mortality and the development of chronic lung allograft dysfunction (CLAD)) were assessed using a Cox proportional hazards and time-to-event outcomes were estimated using the Kaplan-Meier method.

RESULTS

LTX recipients with bronchiectasis experienced a high rate of pre- and post-transplant Pseudomonas colonization compared to other diseases with statistical significance (p < 0.001 and p < 0.001, respectively). Nevertheless, long-term survival in bronchiectasis was as great as non-bronchiectasis (Log-rank p = 0.522), and the bronchiectasis was not a trigger for death (HR 1.62, 95% CI 0.63-4.19). On the other hand, the chance of CLAD onset in bronchiectasis was comparable to non-bronchiectasis (Log-rank p = 0.221), and bronchiectasis was not a predictor of the development of CLAD (HR 1.88, 95% CI 0.65-5.40).

CONCLUSIONS

Despite high prevalence of pre- and post-transplant Pseudomonas colonization, the outcome in LTX recipients with bronchiectasis other than CF was comparable to those without bronchiectasis.

Recovery of physical function in lung transplant recipients with sarcopenia

Background

Lung transplant (LTX) can provide a survival benefit and improve physical function for selected patients with advanced pulmonary disease. Sarcopenia is a systemic muscle-failure that can be found in a variety of life stages and disabilities. In this study, we follow the evolution of each variable defined in sarcopenia and the outcomes in LTX recipients with post-transplant sarcopenia.

Methods

Patients who underwent LTX at Tohoku University Hospital between 2013 and 2018 were consecutively included in the retrospective cohort study, with follow-up to 2019. Sarcopenia was defined by low muscle mass (the cross-sectional area (CSA) of erector spinae muscle (ESM) in thoracic CT with a threshold < 17.24 cm²/m²) and either low muscle strength (hand-grip with a threshold of < 26 kg in males and of < 18 kg in females) or physical performance (6-min walk distance with a threshold < 46.5% of predicted distance).

Results

Fifty-five recipients were included into the study, of whom 19 patients were defined as sarcopenic and 36 as non-sarcopenic. The muscle mass improved after transplant in both sarcopenic and non-sarcopenic individuals: the median ESM-CSA enlarged from 17.25 cm²/m² in 2 months post-LTX to 18.55 cm²/m² in 12 months (p < 0.001) and 17.63 cm²/m² in 36 months (p < 0.001) in non-sarcopenic individuals, while in sarcopenic patients it improved from 13.36 cm²/m² in 2 months to 16.31 cm²/m² in 12 months (p < 0.005) and 18.01 cm²/m² in 36 months (p < 0.001). The muscle mass in sarcopenia substantially recovered to close to non-sarcopenic conditions within 36-months (p < 0.001 in 2 months and p = 0.951 in 36 months). Accordingly, muscle strength and physical performance in both groups improved over time. No difference in survival was seen in both groups (Log-rank p = 0.096), and sarcopenia was not associated with an overall hazard of death (p = 0.147). There was no difference in the cumulative incidence of chronic lung allograft dysfunction between patients with or without sarcopenia (Log-rank p = 0.529).

Conclusions

Even patients with post-transplant sarcopenia have a chance to recover physical function to levels close to those without sarcopenia several years post LTX.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01442-5.