Organ Allocation Research Articles

Impact of allele-specific anti–human leukocyte antigen class I antibodies on organ allocation

Technological advances in the field of histocompatibility have allowed us to define anti–human leukocyte antigen (HLA) antibody specificity at the allelic level. However, how allele-specific antibodies affect organ allocation is poorly studied. We examined allelic specificities of class I HLA antibodies in 6726 consecutive serum samples from 2953 transplant candidates and evaluated their impact on the corresponding crossmatch and organ allocation. Out of 17 class I HLA antigens represented by >1 allele in the LABScreen single antigen bead assay, 12 had potential allele-specific reactivity. Taking advantage of our unbiased cohort of deceased donor-candidate testing (123,135 complement-dependent cytotoxicity crossmatches between 2014 and 2017), we estimated that the presence of allele-specific antibody detected using a single antigen bead assay (median fluorescence intensity, >3000) against only the rare allele was a poor predictor of a positive complement-dependent cytotoxicity crossmatch, with a positive predictive value of 0% to 7%, compared with 52.5% in allele-concordant class I HLA antibodies against A or B locus antigens. Further, we confirmed allele-specific reactivity using flow crossmatch in 3 scenarios: A11:01/A11:02, A68:01/A68:02, and B44:02/B44:03. Our results suggest that allele-specific antibodies may unnecessarily exclude transplant candidates (up to 10%) from organ offers by overcalling unacceptable antigens; incorporation of selective reactivity pattern in allocation may promote precision matching and more equitable allocation.

Priority for Organ Donors in the Allocation of Organs: Priority Rules from the Perspective of Equality of Opportunity.

Should priority in the allocation of organs be given to those who have previously donated or declared their willingness to do so? This article examines the Israeli priority rule in light of two prominent critiques of priority rules, pertaining to failure to reciprocate and unfairness. The scope and content of these critiques are interpreted from the perspective of equality of opportunity. Because the Israeli priority rule may be reasonably criticized for unfairness and failing to reward certain behaviors, the article develops an adjusted priority rule, which removes and adjust the elements in the Israeli priority rule deemed problematic. However, such a priority rule is complex to the extent that it may fail to increase donation rates and furthermore introduce new concerns of fairness, as the better off may be better able to navigate the complex adjusted priority rule.

Worldwide organ allocation systems for pediatric lung transplantation.

Pediatric lung transplantation (LTX) remains limited by the scarcity of small donor lungs, particularly in less populated parts of the world. Optimal organ allocation, including the prioritization and ranking of pediatric LTX candidates, and the appropriate matching of pediatric donors to recipients have been crucial elements in improving pediatric LTX outcomes. We aimed to elucidate the various pediatric lung allocation practices worldwide. A global survey of current pediatric solid organ transplantation deceased donation allocation practices was conducted by the International Pediatric Transplant Association (IPTA), and these policies were subsequently analyzed if publicly available, with focus on pediatric lung transplantation. Significant variation was found in lung allocation systems worldwide both in terms of prioritization and distribution for children. Definition of pediatrics varied from <12 years of age to <18 years of age. While several countries performing LTX for young children do not have a formal system to prioritize pediatric candidates, many countries that perform LTX at higher rates do offer prioritization methods for children: including the United States, United Kingdom, France, Italy, Australia, and countries serviced by Eurotransplant. Certain lung allocation practices for pediatrics are highlighted herein, including the newly instituted Composite Allocation Score (CAS) system in the United States, pediatric matching with Eurotransplant, and pediatric prioritization in Spain. The systems highlighted here explicitly aim to provide judicious and high quality LTX care for children.

Liver Transplantation for Porto-sinusoidal Vascular Liver Disorder: Unmet Questions.

We read with great interest a recent international multicenter study by Marta Magaz et al,1 analyzing post-deceased donor liver transplantation outcomes in 50 of 587 porto-sinusoidal vascular disorder (PSVD) patients registered at 28 participating centers from 1990 to 2020. Additionally, 4 of the 28 centers, performing 4322 LTs, reclassified 29 patients as PSVD after reviewing explant histology registries. We have specific essential points to note. First, the risk of progression of PSVD to advanced liver disease is highly variable, but the specific risk factors and the pathogenic mechanisms leading to these complications should have been researched. Given that the diagnosis of PSVD primarily relied on the recognition of “specific” histologic features on good-quality liver biopsies before liver transplantation (LT),2 the histological changes in the 50 explant livers should have been studied and compared with pre-LT liver biopsies to grade the severity of lesions. Theoretically, it makes sense that the degree of histological changes corresponds to the degree of portal hypertension (PHT) and decompensation. Currently, the individual histologic lesions of PSVD are evaluated using a 2-tiered system for the lesion’s absence (score 0) or presence (score 1). In the presence of similar histological lesions, it is imperative to know why some patients with PSVD developed portal hypertension and decompensation, and others did not. Vice versa, does the grading of histological lesions differ for PSVD patients who develop severe PHT and decompensation compared with those who do not? Maybe the authors can study the 50 explants with this perspective and pick up the other subtle differences between decompensated PSVD versus cirrhosis patients. Second, with PSVD being a presinusoidal disorder, probably a higher portal pressure may be required to produce a similar level of ascites than in patients with cirrhosis. Also, PSVD patients commonly have sinusoidal dilation as a finding in liver samples. Hence, it is important to know if the hepatic venous pressure gradient measurement has been done in these 50 decompensated PSVD patients to identify the presence of sinusoidal PHT.3,4 Third, LT was indicated for 2 of 79 PSVD patients with hepatocellular carcinoma. One had a history of previous hepatitis B with negative HBsAg and undetectable DNA before LT. The other patient had type 2 diabetes and showed obliterative portal venopathy and incomplete septal fibrosis. In patients with hepatocellular carcinoma (HCC), it is imperative to consider the possibility of a coexisting second potential trigger of HCC as PSVD is infrequently associated with HCC,5 and the exact etiopathogenesis of HCC in the setting of PSVD is unclear. Also, incomplete septal cirrhosis may represent regressed cirrhosis and may be unrelated to the risk factors of PSVD.6 In this case, let us assume an overlap of PSVD and parenchymal liver disease, but how to determine the respective contribution of each in the development of HCC is unclear. Hence, these 2 HCC patients may not have been included in the study. Fourth, 21 PSVD patients with severe associated conditions had suboptimal 1-y (85.2 versus 74.3%) and 5-y survival (74.8 versus 45.3%). In the deceased donor liver transplantation setting, the principle of nonfutility is also as important as the principle of utility.7 Hence, organ allocation to these patients should be critically appraised.

Public values and guiding principles for implementing epitope compatibility in kidney transplantation allocation criteria: results from a Canadian online public deliberation

BackgroundEpitope compatibility in deceased donor kidney allocation is an emerging area of precision medicine (PM), seeking to improve compatibility between donor kidneys to transplant candidates in the hope of avoiding kidney rejection. Though the potential benefits of using epitope compatibility are promising, the implied modification of deceased organ allocation criteria requires consideration of significant clinical and ethical trade-offs. As a matter of public policy, these trade-offs should consider public values and preferences. We invited members of the Canadian public to participate in a deliberation about epitope compatibility in deceased donor kidney transplantation; to identify what is important to them and to provide recommendations to policymakers.MethodsAn online public deliberation was conducted with members of the Canadian public, in which participants were asked to construct recommendations for policymakers regarding the introduction of epitope compatibility to kidney allocation criteria. In the present paper, a qualitative analysis was conducted to identify the values reflected in participants’ recommendations. All virtual sessions were recorded, transcribed, and analyzed using NVivo 12 software.ResultsThirty-two participants constructed nine recommendations regarding the adoption of epitope compatibility into deceased donor kidney allocation. Five values were identified that drove participants’ recommendations: Health Maximization, Protection/Mitigation of Negative Impacts, Fairness, Science/Evidence-based Healthcare, and Responsibility to Maintain Trust. Conflicts between these values were discussed in terms of operational principles that were required for epitope compatibility to be implemented in an acceptable manner: the needs for Flexibility, Accountability, Transparent Communication and a Transition Plan. All nine recommendations were informed by these four principles. Participant deliberations were often dominated by the conflict between Health Maximization and Fairness or Protection/Mitigation of Negative Impacts, which was discussed as the need for Flexibility. Two additional values (Efficient Use of Resources and Logic/Rationality) were also discussed and were reasons for some participants voting against some recommendations.ConclusionsPublic recommendations indicate support for using epitope compatibility in deceased donor kidney allocation. A flexible approach to organ allocation decision-making may allow for the balancing of Health Maximization against maintaining Fairness and Mitigating Negative Impacts. Flexibility is particularly important in the context of epitope compatibility and other PM initiatives where evidence is still emerging.

O042 Enzymatic conversion of human blood group A kidneys to universal blood group O

Abstract Introduction The ABO blood group restriction on allocation of donor organs leads to waiting time disadvantages for individuals of more restrictive blood types. Here, we outline the first preclinical use of two enzymes from Flavonifractor plautii to convert human blood group A kidneys to universal blood group O. Methods Six pairs of human kidneys rejected for transplantation and offered for research were used to in this study with approval from the National Research Ethics committee and Research and Development Office (NRES: 15/NE/0408). Three pairs were perfused for 6 h using normothermic machine perfusion (NMP), and three pairs were perfused for 24 h using hypothermic machine perfusion (HMP), with one kidney per pair randomised to enzyme treatment. Cortical biopsies collected throughout perfusion were examined for antigen loss using immunofluorescence microscopy. Results After 2hrs of NMP, a significant loss of 83.4±10.2% blood group A antigen expression was observed compared to pre-treatment levels (p=0.012), while no significant changes were observed in control kidneys (p=0.999). For HMP, a maximal loss of 71.2±21.9% was observed after 6 h (p=0.066), with no decrease observed in the contralateral controls (p=0.977). Haemodynamic perfusion parameters were stable in both cohorts, with no significant difference between control vs treated kidneys. Conclusion Our results show a loss of 70-80% of blood group A antigens in as little as 2 h of NMP and 6 h of HMP. These approaches pave the way for the first clinical studies that could herald the start of a new era that transforms donor organ allocation in kidney transplantation.

Impact of assigning 2-field HLA alleles from real-time PCR on deceased donor assessments and conformance with high resolution alleles.

Waitlisted sensitised transplant recipients with HLA allele level antibodies to their own HLA antigen family are disadvantaged by current deficiencies in HLA typing for deceased donors. This is primarily because at time of organ allocation, HLA typing is provided at antigen level whereas solid phase assays provide allele level antibody definition. The gold standard for HLA allele typing is next generation sequencing (NGS), however time limitations with established NGS systems prevent NGS use for deceased donors. Instead, many labs use a real-time PCR (qPCR) antigen level result for deceased donors, which can disadvantage sensitised patients. Here, we compared assigning qPCR 2-field alleles to qPCR antigen level to determine the impact on virtual crossmatch (VXM) and discuss impact on donor-specific antibody (DSA) assignments. 244 consecutive deceased donors were HLA typed to allelic level by qPCR (LinkSeq SABR) and subsequently by NGS (One Lambda Alltype). The impact of qPCR allele assignments on potential DSA identification was investigated, by retrospectively investigating all 3904 VXMs, where recipient DSA assessments were assessed against donor HLA, was performed within the cohort. There was 96.3% concordance between qPCR and NGS for all allele level loci, with HLA-A; DQB1; and DPB1 having best agreement (99.4%, 98.4% and 99.4% respectively). Of the 3904 VXMs with qPCR allele assignment, there were 13 (<1%) occasions where the potential DSA assignment was impacted, with DQA1 having the most impact. Assigning alleles derived from qPCR to define unacceptable antigens for VXMs, can allow improved access to donor offers for sensitised patients by better defining alleles.

Legislation and Policy Recommendations on Organ and Tissue Donation and Transplantation From an International Consensus Forum.

Using the nominal group technique, a group composed of legal academics, a transplant coordinator/clinician, and a patient partner identified topic areas and recommendations on foundational legal issues. The recommendations were informed by narrative literature reviews conducted by group members based on their areas of expertise, which yielded a range of academic articles, policy documents, and sources of law. Best practices were identified from relevant sources in each subtopic, which formed the basis of the recommendations contained herein. We reached consensus on 12 recommendations grouped into 5 subtopics: (i) legal definitions and legislative scope, (ii) consent requirements for donation' (iii) allocation of organs and tissue' (iv) operation of OTDT systems' and (v) travel for transplant and organ trafficking. We have differentiated between those foundational legal principles for which there is a firm basis of support with those requiring further consideration and resolution. Seven such areas of controversy are identified and discussed alongside relevant recommendations. Our recommendations encompass some principles staunchly enshrined in the OTDT landscape (eg, the dead donor rule), whereas others reflect more recent developments in practice (eg, mandatory referral). Although some principles are widely accepted, there is not always consensus as to how they ought to be implemented. As the OTDT landscape continues to evolve, recommendations must be reconsidered for the law to keep pace with developments in knowledge, technology, and practice.

Heart retransplant recipients with renal dysfunction benefit from simultaneous heart-kidney transplantation

Given ongoing donor shortages, appropriate patient selection for dual-organ transplantation is critical. We evaluated outcomes of heart retransplant with simultaneous kidney transplant (HRT-KT) vs isolated heart retransplant (HRT) across varying levels of renal dysfunction. The United Network for Organ Sharing database identified 1189 adult patients undergoing heart retransplantation between 2005 and 2020. Recipients undergoing HRT-KT (n=251) were compared to those undergoing HRT (n=938). The primary outcome was 5-year survival; subgroup analyses and multivariable adjustment were performed utilizing the following 3 estimated glomerular filtration (eGFR) groups: <30 ml/min/1.73m2, 30-45 ml/min/1.73m2, and >45 ml/min/1.73m2. HRT-KT recipients were older and had longer waitlist times, longer inter-transplant periods, and lower eGFR levels. HRT-KT recipients were less likely to require pretransplant ventilator (1.2% vs 9.0%, p < 0.001) or ECMO (2.0% vs 8.3%, p < 0.001) support but were more likely to have severe functional limitation (63.4% vs 52.6%, p=0.001). After retransplantation, HRT-KT recipients had less treated acute rejection (5.2% vs 9.3%, p=0.02) and more dialysis requirement (29.1% vs 20.2%, p < 0.001) before discharge. Survival at 5-years was 69.1% after HRT and 80.5% after HRT-KT (p < 0.001). After adjustment, HRT-KT was associated with improved 5-year survival among recipients with eGFR <30 ml/min/1.73m2 (HR:0.42, 95% CI: 0.26-0.67) and 30 to 45 ml/min/1.73m2 (HR:0.29, 95% CI 0.13-0.65), but not among those with eGFR>45 ml/min/1.73sm2 (HR 0.68, 95% CI 0.30-1.54). Simultaneous kidney transplantation is associated with improved survival following heart retransplantation in patients with eGFR <45 ml/min/1.73m2 and should be strongly considered to optimize organ allocation stewardship.

Effects of irrigation regime on soil hydrothermal microenvironment, cotton biomass, and yield under non-film drip irrigation system in cotton fields in southern Xinjiang, China

Non-film drip irrigation cotton planting mode can effectively solve the problem of residual film pollution in arid areas and promote sustainable agricultural development. However, the research on the efficient irrigation regime and soil hydrothermal microenvironment suitable for non-film drip irrigation cotton planting is scarce. Considering this, using the data monitoring technology based on internet of things sensors, we set 3 different irrigation treatments in 2020–2021. In the flowering and boll setting stage, cotton was watered for 4 times (W4), 6 times (W6), and 8 times (W8) with a single irrigation amount of 69 mm for each of these 3 treatments, and the last time irrigation amount under W8 treatment was 52.2 mm. At the seedling stage, the cotton was not irrigated under each treatment. At the squaring stage, the irrigation times and single irrigation amount were the same under each treatment. The results showed that the average soil water content (SWC) in the 50–110 cm soil layer was increased obviously with the increase in the total irrigation amount. Compared with W4 and W8 treatments, W6 treatment exhibited the highest the soil temperature in the 10–30 cm soil layer in the full boll stage and boll opening stage and the highest soil effective accumulated temperature (SEAT) from initial flowering stage to boll opening stage. The reproductive organ allocation rate in two years was 3.6 % and 2 % higher under W6 than under W8, respectively. With the increase of total irrigation amount, the cotton yield was increased, but the irrigation water use efficiency (IWUE) was decreased. The highest cotton yield was achieved under W8 treatment, but it was not significantly different from that under W6 treatment, while IWUE was significantly lower under W8 than under W6. The effective air temperature (EAT) had the greatest positive impact on the average effective soil temperature (EST) in 10–50 cm soil layer, while the cumulative irrigation amount (CIA) had a negative impact on average EST in 10–50 cm soil layer. Evapotranspiration (ET) and SEAT were positively correlated with biomass accumulation amount and lint yield. In summary, the irrigation regimes of 2 times of irrigation at the squaring stage with a single irrigation amount of 45 mm and 6 times of irrigation at the flowering and boll setting stage with a single irrigation amount of 69 mm can be applied to the non-film cotton cultivation mode in southern Xinjiang. Our findings provide a reference for the application of agricultural internet of things technology in soil hydrothermal microenvironment of non-film cotton fields in Xinjiang.

Demographic inequities exist and influence transplant outcomes in liver transplantation for acute alcohol-associated hepatitis

BackgroundLiver transplantation has inherent disparities but data is scarce in liver transplant (LT) candidates with acute alcohol-associated hepatitis (AAH). We aimed to investigate demographic inequities and its impact on survival outcomes among AAH LT candidates. MethodsA retrospective analysis using the United Network of Organ Sharing database was conducted between 2000 and 2021. 25 981 LT recipients with alcohol-associated liver cirrhosis and 662 recipients with AAH were included. Waitlisted candidates were also evaluated. ResultsIn comparison with alcohol-associated liver cirrhosis, AAH LT recipients were more likely Asian or “other” race and younger. Hispanics demonstrated better graft and patient survival (p < 0.05) but were less likely to be waitlisted and transplanted for AAH than for liver cirrhosis. Women with AAH were more likely to be waitlisted and transplanted. Pre-existing diabetes and male sex were associated with higher graft failure (25% and 8% respectively). Increasing recipient age were 2% more likely to experience negative outcomes. Chronicity of liver disease did not impact graft (p = 0.137) or patient survival (p = 0.145). ConclusionOur results revealed demographic factors have a significant impact on transplant listing, organ allocation and survival outcomes. Further investigations are imperative to minimize disparities in LT evaluation and provide equity in healthcare.

(523) Impact of the Donor Organ Allocation Change on Heart Transplant of Patients with Small Body Surface Area

(523) Impact of the Donor Organ Allocation Change on Heart Transplant of Patients with Small Body Surface Area

(525) Impact of the Donor Organ Allocation Change on Heart Transplant of Patients ≥65 Years of Age

(525) Impact of the Donor Organ Allocation Change on Heart Transplant of Patients ≥65 Years of Age

(524) Impact of the Donor Organ Allocation Change on Heart Transplant of Latinos

(524) Impact of the Donor Organ Allocation Change on Heart Transplant of Latinos

Impact of institutional case volume of solid organ transplantation on patient outcomes and implications for healthcare policy in Korea.

Solid organ transplantation is distinguished from other high-risk surgical procedures by the fact that it utilizes an extremely limited and precious resource and requires a multidisciplinary team approach. For several decades, institutional experience, as quantified by center volume, has been shown to be strongly associated with patient outcomes and graft survival after solid organ transplantation. The United States has implemented a minimum case volume requirement and performance standards for accreditation as a validated transplantation center. Solid organ transplantation in Europe is also governed by the European Union, which monitors patient outcomes and organ allocation. The number of solid organ transplantation cases in Korea is increasing, with patient outcomes comparable to international standards. However, Korea has outdated regulations regarding hospital facilities, and performance indicators including patient outcomes after transplantation are not monitored. Therefore, centers perform solid organ transplantation with no meaningful oversight. In this review, data regarding the impact of institutional case volume of kidney, liver, lung, and heart transplantation are summarized, followed by a description of current transplantation center regulations in the United States and Europe. The basis for the necessity of adequate transplantation center regulations in Korea is presented.

Contextual Vulnerability Should Guide Fair Subject Selection in Xenotransplantation Clinical Trials

Contextual Vulnerability Should Guide Fair Subject Selection in Xenotransplantation Clinical Trials

Substance use and solid organ transplantation in adolescents and young adults: Current findings and implications.

Understanding the role of substance use is important in the equitable allocation of solid organs and may present an opportunity for improving outcomes among substance users who receive transplants. This scoping review presents findings related to substance use among pediatric and young adult transplant populations and suggests future directions. A scoping review was conducted seeking studies related to substance use in pediatric and young adult transplant populations under the age of 39 years. Studies were deemed eligible if they collected data or addressed policy concerns and participants' mean age was below 39 years. Twenty-nine studies were identified as eligible for this review. Overall, policies around substance use are largely inconsistent throughout both pediatric and adult transplant centers. Findings indicated that substance use among pediatric and young adult transplant recipients is similar to or lower than healthy peers. Few studies addressed marijuana use and opioid misuse, among other substances. There is a general dearth of research on substance use in this population. The current findings suggest that substance use, although relatively less common, affects eligibility for transplant, may lead to poor outcomes, and affects medication adherence. Inconsistent substance use policies in transplant centers have the potential to result in bias. However, more research is needed on the effects of substance use among pediatric and young adult transplant candidates and recipients as well as on equitable policies for organ allocation for individuals who use substances.

The utility of machine learning for predicting donor discard in abdominal transplantation.

Increasing access and better allocation of organs in the field of transplantation is a critical problem in clinical care. Limitations exist in accurately predicting allograft discard. Potential exists for machine learning to provide a balanced assessment of the potential for an organ to be used in a transplantation procedure. We accessed and utilized all available deceased donor United Network for Organ Sharing data from 1987 to 2020. With these data, we evaluated the performance of multiple machine learning methods for predicting organ use. The machine learning methods trialed included XGBoost, random forest, Naïve Bayes (NB), logistic regression, and fully connected feedforward neural network classifier methods. The top two methods, XGBoost and random forest, were fully developed using 10-fold cross-validation and Bayesian optimization of hyperparameters. The top performing model at predicting liver organ use was an XGBoost model which achieved an AUC-ROC of .925, an AUC-PR of .868, and an F1 statistic of .756. The top performing model for predicting kidney organ use classification was an XGBoost model which achieved an AUC-ROC of .952, and AUC-PR of .883, and an F1 statistic of .786. The XGBoost method demonstrated a significant improvement in predicting donor allograft discard for both kidney and livers in solid organ transplantation procedures. Machine learning methods are well suited to be incorporated into the clinical workflow; they can provide robust quantitative predictions and meaningful data insights for clinician consideration and transplantation decision-making.

Clinical prediction model for prognosis in kidney transplant recipients (KIDMO): study protocol

BackgroundMany potential prognostic factors for predicting kidney transplantation outcomes have been identified. However, in Switzerland, no widely accepted prognostic model or risk score for transplantation outcomes is being routinely used in clinical practice yet. We aim to develop three prediction models for the prognosis of graft survival, quality of life, and graft function following transplantation in Switzerland.MethodsThe clinical kidney prediction models (KIDMO) are developed with data from a national multi-center cohort study (Swiss Transplant Cohort Study; STCS) and the Swiss Organ Allocation System (SOAS). The primary outcome is the kidney graft survival (with death of recipient as competing risk); the secondary outcomes are the quality of life (patient-reported health status) at 12 months and estimated glomerular filtration rate (eGFR) slope. Organ donor, transplantation, and recipient-related clinical information will be used as predictors at the time of organ allocation. We will use a Fine & Gray subdistribution model and linear mixed-effects models for the primary and the two secondary outcomes, respectively. Model optimism, calibration, discrimination, and heterogeneity between transplant centres will be assessed using bootstrapping, internal-external cross-validation, and methods from meta-analysis.DiscussionThorough evaluation of the existing risk scores for the kidney graft survival or patient-reported outcomes has been lacking in the Swiss transplant setting. In order to be useful in clinical practice, a prognostic score needs to be valid, reliable, clinically relevant, and preferably integrated into the decision-making process to improve long-term patient outcomes and support informed decisions for clinicians and their patients. The state-of-the-art methodology by taking into account competing risks and variable selection using expert knowledge is applied to data from a nationwide prospective multi-center cohort study. Ideally, healthcare providers together with patients can predetermine the risk they are willing to accept from a deceased-donor kidney, with graft survival, quality of life, and graft function estimates available for their consideration.Study registrationOpen Science Framework ID: z6mvj

Effects of drought stress on water content and biomass distribution in summer maize(Zea mays L.).

The resource allocation of different component organs of crops under drought stress is a strategy for the coordinated growth of crops, which also reflects the adaptability of crops to drought condition. In this study, maize variety namely 'Denghai 618', under the ventilation shed, two treatment groups of light drought (LD) and moderate drought (MD), and the same rehydration after drought are set, as well as the normal water supply for control in shed (CS). The drought experiment was conducted in the jointing-tasseling stage in 2021. The effects of different drought stress on the water content and biomass allocation of each component organ were analyzed. The results showed that (1) during the drought period, the water content of each component organ of summer maize decreased in general, but the Water content distribution ratio (WCDR) of the root increased by 1.83%- 2.35%. The WCDR of stem increased by 0.52%- 1.40%. (2) Under different drought treatments, the root biomass (RB) increased 33.94% ~ 46.09%, and fruit biomass (FB) increased 1.46% ~ 2.49%, the leaf biomass (LB) decreased by 8.2% and 1.46% respectively under LD and MD. (3) The allometric growth model constructed under sufficient water is not suitable for drought stress; the allometric exponent α under drought stress is lower than that of the CS: CS (α=1.175) > MD (α = 1.136) > LD (α = 1.048), which also indicates that the impact of existing climate change on grain yield may be underestimated. This study is helpful to understand the adaptive strategies of the coordinated growth of maize component organs under drought stress and provide a reference for the prediction of grain yield under climate change.