Donor—recipient gender mismatch in lung transplantation: Impact on obliterative bronchiolitis and survival

Effects of donor smoking history on early post-transplant lung function measured by oscillometry

Introduction

Prior studies assessing outcomes of lung transplants from cigarette-smoking donors found mixed results. Oscillometry, a non-invasive test of respiratory impedance, detects changes in lung function of smokers prior to diagnosis of COPD, and identifies spirometrically silent episodes of rejection post-transplant. We hypothesise that oscillometry could identify abnormalities in recipients of smoking donor lungs and discriminate from non-smoking donors.

Methods

This prospective single-center cohort study analysed 233 double-lung recipients. Oscillometry was performed alongside routine conventional pulmonary function tests (PFT) post-transplant. Multivariable regression models were constructed to compare oscillometry and conventional PFT parameters between recipients of lungs from smoking vs non-smoking donors.

Results

The analysis included 109 patients who received lungs from non-smokers and 124 from smokers. Multivariable analysis identified significant differences between recipients of smoking and non-smoking lungs in the oscillometric measurements R5-19, X5, AX, R5z and X5z, but no differences in %predicted FEV1, FEV1/FVC, %predicted TLC or %predicted DLCO. An analysis of the smoking group also demonstrated associations between increasing smoke exposure, quantified in pack years, and all the oscillometry parameters, but not the conventional PFT parameters.

Conclusion

An interaction was identified between donor-recipient sex match and the effect of smoking. The association between donor smoking and oscillometry outcomes was significant predominantly in the female donor/female recipient group.

The effect of donor-recipient sex matches on lung transplant survival: An analysis of the United Network for Organ Sharing database

Objective

To investigate the impact of donor-recipient (DR) sex matches on survival after lung transplantation while controlling for size difference in the United Network of Organ Sharing (UNOS) database.

Methods

We performed a retrospective study of 27,423 lung transplant recipients who were reported in the UNOS database (January 2005-March 2020). Patients were divided into groups based on their respective DR sex match: male to male (MM), male to female (MF), female to female, (FF), and female to male (FM). Kaplan-Meier curve and Cox regression with log-rank tests were used to assess 1-, 3-, 5-, and 10-year survival. We also modeled survival for each group after controlling for size-related variables via the Cox regression.

Results

Kaplan-Meier curves showed overall significance at 1-, 3-, 5-, and 10-year end points (P < .0001). Estimated median survival time based on Kaplan-Meier analysis were 6.41 ± 0.15, 6.13 ± 0.18, 5.86 ± 0.10, and 5.37 ± 0.17 years for FF, MF, MM, and FM, respectively (P < .0001). After we controlled for size differences, FF had statistically significantly longer 5- and 10-year survival than all other cohorts. MF also had statistically significantly longer 5- and 10-year survival than FM.

Conclusions

When variables associated with size were controlled for, FF had improved survival than other DR groups. A female recipient may experience longer survival with a female donor's lungs versus a male donor's lungs of similar size.

Act Together and Act Now to Overcome Gender Disparity in Organ Transplantation

Gender disparity refers to the unequal treatment or a perception of individuals based on their gender and arises from differences in socially constructed gender roles. In the field of transplantation, gender inequality arises at different stages, affecting access to medical care, donation practices, and posttransplant followup care. Gender disparity in transplantation is not limited to any geographic region but is thought to be more prevalent in developing nations. An unusually high number of female donations with relatively fewer female recipients is not only attributable to the low economy but a congregation of medical, social, cultural, and psychological factors. Gender disparities can also be shown in transplant-related professional societies. This review highlights the complexities of spousal donation and vulnerability of women, especially in the developing world. There is a growing need to further modify transplant policies to tackle gender disparities, especially in living related donation. Systematic research in the context of gender-related concerns in transplantation will further aid in understanding the complexities and formulating policies for eliminating gender disparities. Gender disparity is a global problem and not merely limited to transplantation.

Predictive Value of CT Biomarkers in Lung Transplantation Survival: Preliminary Investigation in a Diverse, Underserved, Urban Population

INTRODUCTION

Survival following lung transplant is low. With limited donor lung availability, predicting post-transplant survival is key. We investigated the predictive value of pre-transplant CT biomarkers on survival.

METHODS

In this single-center retrospective cohort study of adults in a diverse, underserved, urban lung transplant program (11/8/2017-5/20/2022), chest CTs were analyzed using TeraRecon to assess musculature, fat, and bone. Erector spinae and pectoralis muscle area and attenuation were analyzed. Sarcopenia thresholds were 34.3 (women) and 38.5 (men) Hounsfield Units (HU). Visceral and subcutaneous fat area and HU, and vertebral body HU were measured. Demographics and pre-transplant metrics were recorded. Survival analyses included Kaplan-Meier and Cox proportional hazard.

RESULTS

The study cohort comprised 131 patients, 50 women, mean age 60.82 (SD 10.15) years, and mean follow-up 1.78 (SD 1.23) years. Twenty-nine percent were White. Mortality was 32.1%. Kaplan-Meier curves did not follow the proportional hazard assumption for sex, so analysis was stratified. Pre-transplant EMR metrics did not predict survival. Women without sarcopenia at erector spinae or pectoralis had 100% survival (p = 0.007). Sarcopenia did not predict survival in men and muscle area did not predict survival in either sex. Men with higher visceral fat area and HU had decreased survival (p = 0.02). Higher vertebral body density predicted improved survival in men (p = 0.026) and women (p = 0.045).

CONCLUSION

Pre-transplantation CT biomarkers had predictive value in lung transplant survival and varied by sex. The absence of sarcopenia in women, lower visceral fat attenuation and area in men, and higher vertebral body density in both sexes predicted survival in our diverse, urban population.

The Emerging Role of Biological Sex in Cell Therapy for Spinal Cord Injury

Neural progenitor cell (NPC) transplantation is a promising potential therapy for replacing spinal cord neurons and glial cells following spinal cord injury (SCI). Despite the rapid advancement of NPC transplantation to SCI clinical trials, we still lack understanding of fundamental biology underlying how NPC grafts interact with the injured host nervous system. Our recent study demonstrated a potent effect of biological sex mismatch between donor and host on graft immune rejection. Here we discuss the implications of this study in the context of clinical trials for SCI, and important topics for future research in SCI cell transplantation.

Effects of biological sex mismatch on neural progenitor cell transplantation for spinal cord injury in mice

Despite advancement of neural progenitor cell transplantation to spinal cord injury clinical trials, there remains a lack of understanding of how biological sex of transplanted cells influences outcomes after transplantation. To address this, we transplanted GFP-expressing sex-matched, sex-mismatched, or mixed donor cells into sites of spinal cord injury in adult male and female mice. Biological sex of the donor cells does not influence graft neuron density, glial differentiation, formation of the reactive glial cell border, or graft axon outgrowth. However, male grafts in female hosts feature extensive hypervascularization accompanied by increased vascular diameter and perivascular cell density. We show greater T-cell infiltration within male-to-female grafts than other graft types. Together, these findings indicate a biological sex-specific immune response of female mice to male donor cells. Our work suggests that biological sex should be considered in the design of future clinical trials for cell transplantation in human injury.

In this study, Pitonak et al. report that transplantation of neural progenitor cells derived from male donors trigger an immune rejection response following transplantation into sites of spinal cord injury in female mice.

Favorable, arduous or fatal postoperative pathway within 90 days of lung transplantation

INTRODUCTION

The maximum gain in quality of life after lung transplantation (LT) is expected between six months and one year after LT, as the occurrence of chronic lung allograft dysfunction may mask the beneficial effects beyond one year. Thus, the postoperative period could be the cornerstone of graft success. We sought to describe the factors present before postoperative admission to the ICU and associated with favorable, arduous or fatal pathway within 90 days of LT.

MATERIALS AND METHODS

We conducted a retrospective single-center study between January 2015 and December 2020. Using multinomial regression, we assessed the demographic, preoperative and intraoperative characteristics of patients associated with favorable (duration of postoperative mechanical ventilation < 3 days and alive at Day 90), arduous (duration of postoperative mechanical ventilation ≥ 3 days and alive at Day 90) or fatal (dead at Day 90) pathway within 90 days of LT.

RESULTS

A total of 269 lung transplant patients were analyzed. Maximum graft cold ischemic time ≥ 6 h and intraoperative blood transfusion ≥ 3 packed red blood cells were associated with arduous and fatal pathway at Day 90, whereas intraoperative ECMO was strongly associated with fatal pathway.

CONCLUSION

No patient demographics influenced the postoperative pathway at Day 90. Only extrinsic factors involving graft ischemia time, intraoperative transfusion, and intraoperative ECMO determined early postoperative pathway.

The role of donor-recipient gender matching in lung transplantation: a systematic review

INTRODUCTION

Donor to recipient (D-R) matching in lung transplantation (LTx) is firstly directed by blood group (identity or compatibility), immunological status and morphological criteria. Sex matching is ignored and impact on outcome less investigated.

EVIDENCE ACQUISITION

Systematic review of English literature using PubMed (1990-2019) was performed to evaluate the potential role of D-R matching in determining long-term outcome in patients after LTx. Search terms included (LTx) AND (sex) OR (gender) OR (matching) OR (mismatch) OR (donor characteristics) and were restricted to articles' title. Only articles directly reporting LTx survival outcome according to gender match/mismatch and D-R gender combination in LTx were included. Two authors independently extracted articles using predefined data fields, including study quality indicators. MOOSE Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies applied.

EVIDENCE SYNTHESIS

Nine articles were analyzed and included into this study. All studies analyzed the effect of the different D-R gender combinations on survival while seven of them investigated exclusively the role of sex matching on LTx outcome. In this latter group two out of seven showed a trend towards an overall survival advantage for sex matching LTx combination. The worst survival results were reported for F to M gender combination in 3 studies and for M to F gender combination by 1 study. No differences were reported in remaining 4 studies.

CONCLUSIONS

This systematic review suggests that sex matching and several gender combinations could play a role in determining overall survival rate after LTx. Data deriving from unbiased studies supported that matching female-female (F-F) and male-male (M-M) could improve LTx outcome while FD-MR combination should be avoided. Unfortunately, a good part of the analyzed data are affected by bias due to confounding factors. Up-to-date immunological, hormonal and morphological factors could explain the gender-based difference in LTx outcome. Further investigations should clarify their role and importance to define the effects of gender combinations on survival.

Acute Rejection in the Modern Lung Transplant Era

Acute cellular rejection (ACR) remains a common complication after lung transplantation. Mortality directly related to ACR is low and most patients respond to first-line immunosuppressive treatment. However, a subset of patients may develop refractory or recurrent ACR leading to an accelerated lung function decline and ultimately chronic lung allograft dysfunction. Infectious complications associated with the intensification of immunosuppression can also negatively impact long-term survival. In this review, we summarize the most recent evidence on the mechanisms, risk factors, diagnosis, treatment, and prognosis of ACR. We specifically focus on novel, promising biomarkers which are under investigation for their potential to improve the diagnostic performance of transbronchial biopsies. Finally, for each topic, we highlight current gaps in knowledge and areas for future research.

Absence of evidence that respiratory viral infections influence pediatric lung transplantation outcomes: Results of the CTOTC-03 study

Based on reports in adult lung transplant recipients, we hypothesized that community-acquired respiratory viral infections (CARVs) would be a risk factor for poor outcome after pediatric lung transplant. We followed 61 pediatric lung transplant recipients for 2+ years or until they met a composite primary endpoint including bronchiolitis obliterans syndrome/obliterative bronchiolitis, retransplant, or death. Blood, bronchoalveolar lavage, and nasopharyngeal specimens were obtained with standard of care visits. Nasopharyngeal specimens were obtained from recipients with respiratory viral symptoms. Respiratory specimens were interrogated for respiratory viruses by using multiplex polymerase chain reaction. Donor-specific HLA antibodies, self-antigens, and ELISPOT reactivity were also evaluated. Survival was 84% (1 year) and 68% (3 years). Bronchiolitis obliterans syndrome incidence was 20% (1 year) and 38% (3 years). The primary endpoint was met in 46% of patients. CARV was detected in 156 patient visits (74% enterovirus/rhinovirus). We did not find a relationship between CARV recovery from respiratory specimens and the primary endpoint (hazard ratio 0.64 [95% confidence interval: 0.25-1.59], P = .335) or between CARV and the development of alloimmune or autoimmune humoral or cellular responses. These findings raise the possibility that the immunologic impact of CARV following pediatric lung transplant is different than that observed in adults.

Clinical outcomes and survival following lung transplantation in patients with pulmonary Langerhans cell histiocytosis

BACKGROUND AND OBJECTIVE

Disease-specific outcomes following lung transplantation (LT) in patients with pulmonary Langerhans cell histiocytosis (PLCH) are not well established. We queried the Organ Procurement and Transplantation Network database to identify adult PLCH patients who had undergone LT in the United States.

METHODS

Overall survival data were analysed with Kaplan-Meier curves. Cox proportional hazard model was used to determine the effect of demographic, clinical and physiological variables on post-transplant survival.

RESULTS

A total of 87 patients with PLCH underwent LT in the United States between October 1987 and June 2017, accounting for 0.25% of the total LT during this period. The mean age at LT for PLCH patients was 49 years (range: 19-67 years), with a near equal gender distribution. Bilateral sequential LT was performed in 71 patients (82%). Pulmonary hypertension was present in 85% of patients, with a mean pulmonary artery pressure of 38.5 ± 14.1 mm Hg. The mean pre-transplant forced expiratory volume in 1 s (FEV₁ ) was 41 ± 21% predicted and the mean 6-min walk distance was 221 ± 111 m. Median post-LT survival for PLCH patients was comparable to patients with other lung diseases (5.1 vs 5.5 years, P = 0.76). The actuarial Kaplan-Meier post-LT survival for PLCH patients was 85%, 65%, 49% and 22% at 1, 3, 5 and 10 years, respectively. Female sex (hazard ratio (HR): 0.40, 95% CI: 0.22-0.72), pre-transplant serum bilirubin (HR: 1.66, 95% CI: 1.23-2.26) and serum creatinine (HR: 4.03, 95% CI: 1.01-14.76) were independently associated with post-LT mortality in our cohort.

CONCLUSION

Post-LT survival in patients with PLCH is similar to patients with other lung diseases and is significantly affected by patient gender.

Genomic Mismatch at LIMS1 Locus and Kidney Allograft Rejection

BACKGROUND

In the context of kidney transplantation, genomic incompatibilities between donor and recipient may lead to allosensitization against new antigens. We hypothesized that recessive inheritance of gene-disrupting variants may represent a risk factor for allograft rejection.

METHODS

We performed a two-stage genetic association study of kidney allograft rejection. In the first stage, we performed a recessive association screen of 50 common gene-intersecting deletion polymorphisms in a cohort of kidney transplant recipients. In the second stage, we replicated our findings in three independent cohorts of donor-recipient pairs. We defined genomic collision as a specific donor-recipient genotype combination in which a recipient who was homozygous for a gene-intersecting deletion received a transplant from a nonhomozygous donor. Identification of alloantibodies was performed with the use of protein arrays, enzyme-linked immunosorbent assays, and Western blot analyses.

RESULTS

In the discovery cohort, which included 705 recipients, we found a significant association with allograft rejection at the LIMS1 locus represented by rs893403 (hazard ratio with the risk genotype vs. nonrisk genotypes, 1.84; 95% confidence interval [CI], 1.35 to 2.50; P = 9.8×10^-5). This effect was replicated under the genomic-collision model in three independent cohorts involving a total of 2004 donor-recipient pairs (hazard ratio, 1.55; 95% CI, 1.25 to 1.93; P = 6.5×10^-5). In the combined analysis (discovery cohort plus replication cohorts), the risk genotype was associated with a higher risk of rejection than the nonrisk genotype (hazard ratio, 1.63; 95% CI, 1.37 to 1.95; P = 4.7×10^-8). We identified a specific antibody response against LIMS1, a kidney-expressed protein encoded within the collision locus. The response involved predominantly IgG2 and IgG3 antibody subclasses.

CONCLUSIONS

We found that the LIMS1 locus appeared to encode a minor histocompatibility antigen. Genomic collision at this locus was associated with rejection of the kidney allograft and with production of anti-LIMS1 IgG2 and IgG3. (Funded by the Columbia University Transplant Center and others.).

Effect of Histocompatibility Y Antigen Matching on Graft Survival in Primary Penetrating Keratoplasty

PURPOSE

To investigate the influence of histocompatibility Y (H-Y) antigen matching on corneal graft survival in primary penetrating keratoplasty (PK).

METHODS

Medical records of patients who underwent primary PK at Seoul National University Bundang Hospital between June 2005 and October 2015 were retrospectively analyzed. The eyes were classified into 2 groups: H-Y-compatible (115 eyes) and H-Y-incompatible (23 eyes). The H-Y-compatible group included donor/recipient combinations of male/male (57 eyes), female/male (44 eyes), and female/female (14 eyes). The H-Y-incompatible group included the male/female (23 eyes) combination alone. A subgroup analysis of low- and high-risk patients according to preoperative diagnoses was also performed. Survival analysis was conducted using the Kaplan-Meier method; differences between groups were assessed with a log-rank test.

RESULTS

A total of 138 eyes from 136 patients (age: 58 ± 18 years) were enrolled. Rejection-free graft survival and graft survival were not significantly different between H-Y-compatible and H-Y-incompatible groups (χ = 0.4, P = 0.548; χ = 1.9; P = 0.17, respectively). Preoperative diagnoses of high-risk cases included those with corneal perforation or thinning (8.7%) and infectious keratitis (7.2%). Low-risk cases included corneal opacity (50.0%), bullous keratopathy (25.4%), keratoconus (5.8%), and corneal dystrophy (2.9%). In the high-risk group, rejection-free graft survival rate was significantly higher in the H-Y-compatible group (χ = 3.9, P = 0.049).

CONCLUSIONS

H-Y antigen matching does not influence graft rejection and failure in cases of primary PK. However, matching the H-Y antigen could help reduce graft rejection, especially in preoperatively high-risk patients.

Sex differences on solid organ histological characteristics after brain death1

PURPOSE

To investigate gender differences in the evolution of the inflammatory process in rats subjected to brain death (BD).

METHODS

Adult Wistar rats were divided into three groups: female; ovariectomized female; and male rats. BD was induced using intracranial balloon inflation and confirmed by maximal pupil dilatation, apnea, absence of reflex, and drop of mean arterial pressure. Six hours after BD, histological evaluation was performed in lungs, heart, liver and kidneys, and levels of inflammatory proteins, estrogen, progesterone, and corticosterone were determined in plasma.

RESULTS

In the lungs, females presented more leukocyte infiltration compared to males (p<0.01). Ovariectomized female rat lungs were more hemorrhagic compared to other groups (p<0.001). In the heart, females had higher leukocyte infiltration and tissue edema compared to males (p<0.05). In the liver and kidneys, there were no differences among groups. In female group estradiol and progesterone were sharply reduced 6 hours after BD (p<0.001) to values observed in ovariectomized females and males. Corticosterone levels were similar.

CONCLUSIONS

Sex hormones influence the development of inflammation and the status of organs. The increased inflammation in lungs and heart of female rats might be associated with the acute reduction in female hormones triggered by BD.

Gender differences in long-term survival post-transplant: A single-institution analysis in the lung allocation score era

The purpose of this study was to clarify the significance of recipient gender status on lung transplant outcomes in a large single-institution experience spanning three decades, we analyzed data from all lung transplants performed in our institution since 1986. Kaplan-Meier curves and Cox proportional hazard models were used to evaluate the effect of recipient characteristics on survival and BOS score ≥1-free survival. Logistic regression analysis was used to explore the association of gender with short-term graft function. About 876 lung transplants were performed between 1986 and 2016. Kaplan-Meier survival estimates at 5 years post-transplant for females vs males in the LAS era were 71% vs 58%. In the LAS era, females showed greater unadjusted BOS≥1-free survival than males (35% vs 25%, P=.02) over 5 years. Female gender was the only factor in the LAS era significantly associated with improved adjusted 5-year survival [HR 0.56 (95% CI 0.33, 0.95) P=.03]. Conversely, in the pre-LAS era female gender was not associated with improved survival. Female recipients showed significantly improved survival over 5 years compared to males in the LAS era. A prospective analysis of biologic and immunologic differences is warranted.

The Influence of Donor and Recipient Gender Incompatibility on Corneal Transplant Rejection and Failure

In vascularized organ transplants, gender mismatches have higher rates of immunological rejection. We investigated the influence of gender incompatibility, including H-Y incompatibility, on corneal transplant graft rejection and failure. Patients were included who had undergone a first corneal transplant for keratoconus (KC), Fuchs endothelial dystrophy (FED), pseudophakic bullous keratopathy (PBK), infection and other indications. A Cox regression model was fitted for each indication to determine factors affecting graft failure and rejection at 5 years. The impact of gender, including H-Y, matching was analyzed after accounting for other factors, including known risk factors. Of 18 171 patients, 4314 had undergone a transplant for FED, 4783 for KC, 3669 for PBK, 1903 for infection and 3502 for other disorders. H-Y mismatched (male [M]→female [F]) corneas were at greater risk of graft failure or rejection. For FED, F→F were 40% less likely to fail (p < 0.0001) and 30% less likely to reject (p = 0.01); M→M were 20% less likely to fail (p = 0.04) and 30% less likely to reject (p = 0.01). For KC, M→M matched corneas were 30% less likely to fail (p = 0.05) and 20% less likely to reject (p = 0.01) compared with H-Y mismatches. H-Y antigen mismatched (M→F) patients were at greater risk of rejection or graft failure.

Transfusion with packed red blood cells while awaiting lung transplantation is associated with reduced survival after lung transplantation

BACKGROUND

The effect of pretransplant transfusion of red blood cells on survival after lung transplantation (LTx) has not been studied.

METHODS

The UNOS database was queried from 2005 to 2013 to compare survival in recipients receiving a transfusion while on the LTx wait list.

RESULTS

Of 12 283 adult patients undergoing single or bilateral LTx from May 2005 onwards, 11 801 met inclusion criteria, among whom 512 required transfusion while on the LTx wait list. Transfusion was associated with a higher mortality hazard in unadjusted Cox proportional hazards analysis (HR=1.296; 95% CI: 1.124, 1.494; P<.001), and in a multivariable Cox model (HR=1.178; 95% CI: 1.013, 1.369; P=.033) after multiple imputation was used to complete data on covariates. Propensity score matching was used to match transfusion recipients to nonrecipients on the likelihood of having received transfusions on the wait list, calculated from characteristics at the time of listing. Unadjusted Cox regression stratified on the matched pairs also demonstrated an association between transfusion receipt on the wait list and higher post-transplant mortality hazard (HR=1.494; 95% CI: 1.127, 1.979; P=.005).

CONCLUSIONS

Blood transfusion while on the LTx wait list was associated with diminished patient survival after transplantation.

Lung transplantation and gender effects on survival of recipients with cystic fibrosis

BACKGROUND

The overall life expectancy of women with cystic fibrosis (CF) is shorter compared with men with CF without accounting for lung transplant recipients. However, it is unclear how donor and recipient gender impact long-term outcomes in patients with CF who undergo lung transplantation. The purpose of this study was to determine if the gender disadvantage seen in women with CF before transplant continues to exist after lung transplant and if this is impacted by donor gender.

METHODS

Patients with CF entered in the International Society for Heart and Lung Transplantation registry who were at least 18 years old and received a lung transplant between January 2000 and December 2012 were included and divided into groups based on donor-recipient gender combinations. Kaplan-Meier curves were used to determine post-transplant rates of overall survival and bronchiolitis obliterans syndrome (BOS)-free survival.

RESULTS

The analysis included 4,971 patients undergoing lung transplantation for CF. There was no significant difference in BOS-free survival or overall survival rates between genders or between gender-matched vs gender-mismatched recipients after lung transplantation. However, women with CF underwent transplantation at a younger age and died at an earlier overall age than men with CF.

CONCLUSIONS

Survival after lung transplantation and time to the development of BOS did not differ based on gender or donor-recipient gender combination. However, women with CF continue to demonstrate a poorer overall life expectancy, as their pre-transplant disadvantage could not be overcome after lung transplantation.

Validation of human small airway measurements using endobronchial optical coherence tomography

BACKGROUND

Small airway remodeling is the cardinal feature underlying chronic airway diseases. There is no modality which identifies small airway pathological changes, which is crucial for early diagnosis, efficacy and prognostic assessment.

OBJECTIVE

To evaluate the usefulness of endobronchial optical coherence tomography (EB-OCT) in assessing small airways morphology in vivo.

METHODS

Twelve patients with pulmonary nodules scheduled for lung resection underwent spirometry, multi-detector computed tomography (MDCT) and EB-OCT. We measured D(mean) (mean luminal diameter), Ai (inner luminal area), Aw (airway wall area) and Aw% [Aw/(Ai + Aw) × 100%] from the 3rd to 5th generation bronchi of RB9 segment by MDCT. D(mean), Ai, Aw and Aw% from the 3rd to 9th generation bronchi of RB9 segment were measured by EB-OCT and histology. Correlations of these parameters, measured by three different methods, were evaluated. We recruited 4 COPD patients to determine if EB-OCT could identify peripheral airway remodeling.

RESULTS

The 4 parameters, measured by CT and EB-OCT, correlated significantly [D(mean) (r = 0.991), Ai (r = 0.997), Aw (r = 0.997), Aw% (r = 0.991), all P < 0.01]. Significant correlation were found for these parameters, measured by histology and EB-OCT, from the 3rd to 5th generation bronchi [D(mean) (r = 0.989), Ai (r = 0.997), Aw (r = 0.999), Aw% (r = 0.988), all P < 0.01], and from the 6th to 9th generation bronchi [D(mean) (r = 0.979), Ai (r = 0.997), Aw (r = 0.994) and Aw% (r = 0.988), all P < 0.01]. Significant small airways morphological abnormalities were observed in COPD patients.

CONCLUSIONS

EB-OCT, a minimally invasive imaging modality with high-resolution, is useful and clinically practical for assessing proximal and distal airways of human compared with CT and histology.

Preconditioning donor livers with cromolyn or compound 48/80 prolongs recipient survival in a rat orthotopic liver transplantation model

BACKGROUND

Acute rejection (AR) remains a challenge in organ transplantation. Preconditioning donor organs can reduce AR and prolong survival. Whether preconditioning with cromolyn (CRM), a mast cell (MC) stabilizer, or compound 48/80 (CMP 48/80), a MC degranulator, can alleviate AR and prolong survival has not been studied.

METHODS

We used the male-DA-to-female-Lewis-rat orthotopic liver transplantation (OLT) model. Donors were preconditioned with CRM in a MC stabilizing way (CRM group) or CMP 48/80 in a MC depleting way (CMP 48/80 group). Rats preconditioned with phosphate-buffered saline were used as controls (PBS group). After preconditioning, OLT surgeries were carried out. OLT male-Lewis-to-female-Lewis-rats were used as the syngeneic group (syngeneic group).

RESULTS

Rats in the PBS group developed AR rapidly and died at 7.40 ± 1.14 days. Rats in the CRM and CMP 48/80 groups had significantly slower rejections and died at day 17.40 ± 1.67 or 14.20 ± 2.28, respectively (P < .05). Rats in the syngeneic group survived more than 60 days. Rejection activity indexes (RAIs) and liver functions were all alleviated through CRM or CMP 48/80 preconditioning. Interferon-γ messenger RNA (mRNA) expressions were reduced and interleukin-10 mRNA levels were higher in allografts in the CRM and CMP 48/80 groups, compared with the PBS group. These were confirmed by testing serum interferon-γ and interlerkin-10.

CONCLUSION

Preconditioning donor livers with CRM or CMP 48/80 can reduce AR and prolong survival of recipients after OLT.

Donor-recipient matching in lung transplantation: which variables are important?†

OBJECTIVES

Donor to recipient (D/R) matching in lung transplantation (LTx) is usually directed by blood group (identity or compatibility) and predicted total lung capacity (pTLC) based on height and age. Other donor (D) and recipient (R) characteristics such as cytomegalovirus (CMV) serology (±), gender [male (M)/ female (F)] and age are often ignored, but the impact of D/R mismatch for these variables and their combinations on outcome is less investigated.

METHODS

The early and late outcomes in 461 lung recipients (149 single-lung and 312 double-lung) transplanted between July 1991 and December 2009 were explored, comparing different D/R combinations for gender (M/F), age (<20/21 to 45/≥ 45 years), CMV (±), blood group (identical/compatible) and pTLC (-9%Δ, +11%Δ).

RESULTS

Overall 5-, 10-, 15- and 20-year survival rates were 69, 50, 37 and 37%, respectively, and were significantly better in females {HR [95% confidence interval (CI)]: 0.5 (0.3-0.9); P = 0.023} and worse in older recipients [HR (95% CI): 1.6 (1.2-2.2); P = 0.003]. On univariate analysis, survival was significantly worse in recipients with gender opposite to that of the donor (39% for mismatch vs 51% for match at 10 years; P = 0.04), but not for other D/R matching variables: age (P = 0.89), pTLC (P = 0.14), CMV (P = 0.15), blood group (P = 0.82) and their combinations. The best survival at 5 years was seen in female donor (DF)/female recipient (RF) (80%), the worst in DF/male recipient (RM) (47%), and intermediate in male donor (DM)/RF (72%) and DM/RM (63%); P = 0.0001. On multivariate analysis, D/R gender mismatch was found to be the sole negative predictive factor for survival with an 80% increased risk of mortality [HR (95% CI): 1.8 (1.1-2.8); P = 0.01].

CONCLUSIONS

In our patient cohort, survival after LTx was superior in female and younger recipients. D/R gender mismatch may be an important prognostic factor for long-term outcome. A gender combination of DF/RM should be avoided. The exact reasons for these differences remain speculative.

Lung donor selection criteria

The criteria that define acceptable physiologic and social parameters for lung donation have remained constant since their empiric determination in the 1980s. These criteria include a donor age between 25-40, a arterial partial pressure of oxygen (PaO2)/FiO2 ratio greater than 350, no smoking history, a clear chest X-ray, clean bronchoscopy, and a minimal ischemic time. Due to the paucity of organ donors, and the increasing number of patients requiring lung transplant, finding a donor that meets all of these criteria is quite rare. As such, many transplants have been performed where the donor does not meet these stringent criteria. Over the last decade, numerous reports have been published examining the effects of individual acceptance criteria on lung transplant survival and graft function. These studies suggest that there is little impact of the historical criteria on either short or long term outcomes. For age, donors should be within 18 to 64 years old. Gender may relay benefit to all female recipients especially in male to female transplants, although results are mixed in these studies. Race matched donor/recipients have improved outcomes and African American donors convey worse prognosis. Smoking donors may decrease recipient survival post transplant, but provide a life saving opportunity for recipients that may otherwise remain on the transplant waiting list. No specific gram stain or bronchoscopic findings are reflected in recipient outcomes. Chest radiographs are a poor indicator of lung donor function and should not adversely affect organ usage aside for concerns over malignancy. Ischemic time greater than six hours has no documented adverse effects on recipient mortality and should not limit donor retrieval distances. Brain dead donors and deceased donors have equivalent prognosis. Initial PaO2/FiO2 ratios less than 300 should not dissuade donor organ usage, although recruitment techniques should be implemented with intent to transplant.

Impact of donor-recipient gender on kidney graft and patient survival: short- and long-term outcomes

PURPOSE

Donor and recipient gender influence on post-transplant kidney and patient survival is still controversial, and the literature data do not present unanimous conclusions. The aim of this study was to evaluate the effect of gender disparities between donor and recipient in 963 kidney transplants performed at our center from January 2000 to December 2010.

METHODS

The patients were subdivided into four groups according to recipient and donor gender: male donor-to-male recipient (MDMR; n = 305), male donor-to-female recipient (MDFR; n = 203), female donor-to-female recipient (FDFR; n = 206), and female donor-to-male recipient (FDMR; n = 249). Independent sample's t test and one-way ANOVA were used for statistical analyses. Graft and patient survival were calculated by the Kaplan-Meier method and compared using the log rank test.

RESULTS

There were no statistically significant differences between the groups with regard to age, cold ischemia time, delayed graft function, primary non-function, and episodes of acute and chronic rejection. Moreover, no difference in either graft (p = 0.92) or patient (p = 0.41) survival at 1, 3, and 5 years was observed. However, female recipients had significantly lower serum creatinine values and higher estimated GFR, particularly if they received a male donor kidney, and these findings were stable up to 3-year post-transplantation.

CONCLUSIONS

No impact of gender on short- or long-term graft and patient survival was observed in deceased kidney transplantation. However, we report a lower creatinine level in the male donors to female recipients group as compared with other recipient-donor gender combinations, although this difference loses statistical significance after the third-year post-transplantation.

Influence of donor-recipient gender mismatch on graft function and survival following lung transplantation

OBJECTIVES

In current practice, donors and recipients are not matched for gender in lung transplantation. However, some data have suggested a possible effect of gender combinations on lung transplant outcomes. We examined whether donor-recipient (D/R) gender mismatch is related to adverse outcomes after lung transplantation in terms of early and long-term graft function and survival.

METHODS

We reviewed 256 donors and lung transplant recipients over a 14-year period. Patients were distributed into four groups: Group A (D/R: female/female), Group B (D/R: male/male), Group C (D/R: female/male), Group D (D/R: male/female). Donor and recipient variables were compared among groups, including early graft function, 30-day mortality, freedom from bronchiolitis obliterans syndrome (BOS), and long-term survival.

RESULTS

Group A: 57 (22%), Group B: 99 (39%), Group C: 62 (24%), Group D: 38 (15%) transplants (P = 0.001). Donor age was 29 ± 14, 27 ± 12, 33 ± 13 and 23 ± 12 years for Groups A, B, C and D, respectively (P = 0.004). Recipient age was 31 ± 15, 44 ± 17, 42 ± 16 and 30 ± 16 years for Groups A, B, C and D, respectively (P = 0.000). PaO2/FiO2 (mmHg) 24 h post-transplant was: Group A: 276 ± 144, Group B: 297 ± 131, Group C: 344 ± 133 and Group D: 238 ± 138 (P = 0.015). Primary graft dysfunction developed in 23, 14, 17 and 21% of recipients from Groups A, B, C and D, respectively (P = 0.45). Operative mortality was 4.4, 6.5, 5.2 and 2%, for recipients from Groups A, B, C and D, respectively (P = 0.66). Freedom from BOS was 73, 59 and 36% for gender-matched transplants vs 76, 67 and 40% for gender-mismatched transplants at 3, 5 and 10 years, respectively (P = 0.618), without differences among groups. A non-significant survival benefit was observed for female recipients, irrespective of the donor gender.

CONCLUSIONS

Donor-recipient gender mismatch does not have a negative impact on early graft function and mortality following lung transplantation. There is a trend towards a survival benefit for female recipients, irrespective of the donor gender.

Influence of gender donor-recipient combinations on survival after human lung transplantation

BACKGROUND

In the current practice of lung transplantation, donor and recipient genders are neither directly considered nor matched. However, some data have suggested a possible effect of gender combinations on survival following lung transplantation.

METHODS

A total of 249 adult lung transplant recipients at a single center between February 1988 and December 2008, were analyzed retrospectively for donor-recipient gender matching. We compared the mortality by calculating one-term survival rates after transplantation using the Kaplan-Meier method with comparisons using the log-rank (Mantel-Cox) test. Statistical significance of the mean effects of size matching was assessed by paired Student t tests and Wilcoxon signed rank tests.

RESULTS

Kaplan-Meier survival analysis shown that male compared to female recipients did not have an effect on outcomes after lung transplantation at 5 years (P=.5379), 10 years (P=.107), 15 years (P=.0841), 20 years (P=.0711). No effect of gender on lung transplantation outcomes was observed with donor-recipient gender mismatches at 5 years (P=.1804), 10 years (P=.1457), 15 years (P=.0731), or 20 years (P=.0629). Similarly, no differences were observed for each gender combination. The degree of size matching was defined as the ratio of donor-to-recipient predicted total lung capacity. The ratios were similar for the donor-recipient gender match and significantly different for the donor-recipient gender mismatch.

CONCLUSIONS

These analyses suggested that gender was not a significant independent risk factor affecting survival after lung transplantation. Size mismatch caused by gender mismatch did not increase mortality.

Single-lung transplantation: does side matter?

OBJECTIVE

Single-lung transplantation (SLTx) is a valid treatment option for patients with non-suppurative end-stage pulmonary disease. This strategy helps to overcome current organ shortage. Side is usually chosen based on pre-transplant quantitative perfusion scan, unless specific recipient considerations or contralateral lung offer dictates opposite side. It remains largely unknown whether outcome differs between left (L) versus right (R) SLTx.

METHODS

Between July 1991 and July 2009, 142 first SLTx (M/F=87/55; age=59 (29-69) years) were performed from 142 deceased donors (M/F=81/61; age=40 (14-66) years) with a median follow-up of 32 (0-202) months. Indications for SLTx were emphysema (55.6%), pulmonary fibrosis (36.6%), primary pulmonary hypertension (0.7%), and others (7.0%). Recipients of L-SLTx (n=72) and R-SLTx (n=70) were compared for donor and recipient characteristics and for early and late outcome.

RESULTS

Donors of L-SLTx were younger (37 (14-65) vs 43 (16-66) years; p=0.033). R-SLTx recipients had more often emphysema (67.1% vs 44.4%; p=0.046) and replacement of native lung with ≥ 50% perfusion (47.1% vs 23.6%; p=0.003). The need for bypass, time to extubation, intensive care unit (ICU) and hospital stay, and 30-day mortality did not differ between groups. Overall survival at 1, 3, and 5 years was 78.4%, 60.5%, and 49.4%, respectively, with a median survival of 60 months, with no significant differences between sides. Forced expiratory volume in 1s (FEV₁) improved (p<0.01) in both groups to comparable values up to 36 months. Complications overall (44.4% vs 50.0%) or in allograft (25.0% vs 24.3.0%) as well as time to bronchiolitis obliterans syndrome (BOS) (35 months) and 5-year freedom from BOS (68.9% vs 75.0%) were comparable after L-SLTx versus R-SLTx, respectively. There were no differences in all causes of death (p=0.766). On multivariate analysis, BOS was a strong negative predictor for survival (hazard ratio (HR) 6.78; p<0.001), whereas side and mismatch for perfusion were not.

CONCLUSION

The preferred side for SLTx differed between fibrotic versus emphysema recipients. Transplant side does not influence recipient survival, freedom from BOS, complications, or pulmonary function after SLTx. Besides surgical considerations in the recipient, offer of a donor lung opposite to the preferred side should not be a reason to postpone the transplantation until a better-matched donor is found.

Acute cellular rejection is a risk factor for bronchiolitis obliterans syndrome independent of post-transplant baseline FEV1

BACKGROUND

Post-transplant baseline forced expiratory volume in 1 second (FEV(1)) constitutes a systematic bias in analyses of bronchiolitis obliterans syndrome (BOS). This retrospective study evaluates risk factors for BOS adjusting for the confounding of post-transplant baseline FEV(1).

METHODS

A multivariate survival and competing risk analysis of a large consecutive series of patients (n = 389) from a national center 1992 to 2004. Exclusion criteria were patients not surviving at least 3 months after transplantation (n = 39) and no available lung function measurements (n = 4).

RESULTS

The first maximum FEV(1) occurred at a median 183 days post-transplant. Freedom from BOS was 81%, 53%, 38% and 15%, and cumulative incidence of BOS was 18%, 43%, 57% and 77% at 1, 3, 5 and 10 years post-transplantation, respectively. Acute cellular rejection was independently associated with an increased cause-specific hazard of BOS (hazard ratio 1.4, confidence interval 1.1 to 1.8, p = 0.009). The absolute value of baseline FEV(1) was a significant confounder in all survival and competing risk analyses of BOS (p < 0.05).

CONCLUSION

Despite early diagnosis and prompt treatment, acute cellular rejection remains an independent risk factor for the development of BOS after adjusting for the confounding of post-transplant baseline FEV(1).

H-Y incompatibility predicts short-term outcomes for kidney transplant recipients

A recent report suggested that female recipients of male deceased-donor kidneys are at increased risk for graft failure because of H-Y antigen mismatch. In an attempt to confirm and extend these results, we studied all adult recipients of deceased-donor kidney transplants from 1990 through 2004 in the US Renal Data System. Compared with all other gender combinations, female recipients of male donor kidneys had a 12% increased risk for graft failure at 1 yr (hazard ratio 1.12; 95% confidence interval 1.05 to 1.19) but no excess risk at 10 yr (hazard ratio 1.03; 95% confidence interval 0.98 to 1.07). We observed a similar pattern of short- and long-term risk for both death-censored graft failure and mortality. The main results were consistent across several prespecified patient subgroups and were robust to sensitivity analyses. In conclusion, compared with other recipient-donor gender combinations, female recipients of male donor kidney transplants in the United States have an increased short-term risk but not long-term risk for adverse outcomes.

Risk factors for early primary graft dysfunction after lung transplantation: a registry study

BACKGROUND

Primary graft dysfunction (PGD) is a leading cause of early morbidity and mortality in lung transplantation. We sought to identify risk factors for PGD using the United Network for Organ Sharing/International Society for Heart and Lung Transplant (UNOS/ISHLT) Registry.

METHODS

A total of 6984 lung transplants between 1994 and 2002 were available for analysis. Potential risk factors were tested for association with PGD and multivariable logistic regression was applied to adjust for confounding.

RESULTS

The overall incidence of PGD was 10.7% (95% CI 9.9-11.4). In multivariable analyses, factors independently associated with PGD were donor age >45 yr (p < 0.001); donor head trauma (p = 0.03); recipient body mass index >25 kg/m(2) (p = 0.005); recipient female gender (p = 0.001); use of Eurocollins preservation solution (p = 0.001); single lung transplant (p = 0.005); increased ischemic time (p < 0.001); and elevated recipient pulmonary artery systolic pressure at transplant (p < 0.001). Recipient transplant diagnosis was strongly associated with PGD, with primary or secondary pulmonary hypertension (p < 0.001 for both), and idiopathic (p < 0.001) or secondary pulmonary fibrosis (p = 0.011) as significant and independent risk factors for PGD.

CONCLUSIONS

Risk factors for PGD in the UNOS/ISHLT registry are consistent with prior smaller studies. Recipient, donor, and therapy variables are independently associated with PGD, as defined in a large registry.

H-Y as a minor histocompatibility antigen in kidney transplantation: a retrospective cohort study

BACKGROUND

In haematopoietic stem-cell transplantation, male recipients of female grafts have an increased risk of graft-versus-host disease and female recipients have both an increased risk of rejection of male grafts and of specific T-cell and antibody reactivity against H-Y encoded gene products. By contrast, in kidney transplantation, the role of H-Y as a minor histocompatibility antigen has been disputed. We aimed to investigate whether an immunological H-Y effect occurs in kidney transplantation.

METHODS

We did a retrospective cohort study between 1985 and 2004 in 195 516 recipients of allografts from deceased donors. We used multivariate statistical methods to compare graft survival and death-censored graft survival rates for female and male donor kidneys in female and male recipients at 1 and 10 years.

FINDINGS

Graft loss was more common with kidneys from female donors than with those from male donors (p<0.001) after both 1 and 10 years. Female recipients had a lower rate of graft failure between the end of the first year and the end of the tenth year (p<0.001). Compared with all other combinations of sex, transplantation of male donor kidneys into female recipients was associated with an increased risk of graft failure during the first year (hazard ratio [HR] 1.08, 95% CI 1.03-1.14, p=0.003; death censored HR 1.11, 1.04-1.19, p=0.003) and between 2 and 10 years (HR 1.06, 1.01-1.10, p=0.008; death censored HR 1.10, 1.05-1.16, p<0.001).

INTERPRETATION

H-Y minor histocompatibility affects human kidney transplantation.

Challenges in pulmonary fibrosis. 2: Bronchiolocentric fibrosis

Bronchiolocentric fibrosis is essentially represented by the pathological pattern of constrictive fibrotic bronchiolitis obliterans. The corresponding clinical condition (obliterative bronchiolitis) is characterised by dyspnoea, airflow obstruction at lung function testing and air trapping with characteristic mosaic features on expiratory high resolution CT scans. Bronchiolitis obliterans may result from many causes including acute diffuse bronchiolar damage after inhalation of toxic gases or fumes, alloimmune chronic processes after lung or haematopoietic stem cell transplantation, or connective tissue disease (especially rheumatoid arthritis). Airway-centred interstitial fibrosis and bronchiolar metaplasia are other features of bronchiolocentric fibrosis.

Outcome Analysis of Donor Gender in Heart Transplantation

BACKGROUND

Several studies have shown a detrimental effect of female donor gender on the survival of solid-organ transplant recipients, including heart, kidney and liver. We evaluated our own experience in heart transplantation in the cyclosporine era, since 1980, to determine the effect of donor gender on survival.

METHODS

We retrospectively reviewed 869 consecutive patients who underwent primary heart transplantation at Stanford University Medical Center between December 1980 and March 2004. Actuarial life-table data were calculated for survival and freedom from rejection and compared between groups. Multivariate Cox proportional hazard analysis was used to identify predictors of reduced long-term survival.

RESULTS

One-year mortality in male recipients who received a female donor heart (24%) was higher than in male recipients who received male donor heart (13%) (p = 0.009). Actuarial survival rates for male recipients at 1, 5 and 10 years were 86%, 69% and 50% (with male donor), and 76%, 59% and 45% (with female donor) (p = 0.01), respectively. Donor gender had no effect on long-term survival in male recipients < 45 years of age and female recipients. Female donor gender was identified as an independent risk factor for death by multivariate analysis, with an odds ratio of 2.3 (95% confidence interval 1.5 to 3.4, p < 0.001).

CONCLUSIONS

In heart transplantation the detrimental effect of female donor gender on recipient survival is significant but limited to male recipients > 45 years of age. These findings should be considered in the process of donor-recipient matching.