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Although allogeneic hematopoietic cell transplantation (HCT) is the sole potentially curative therapy for patients with poor-risk myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), only a minority of these patients undergo HCT. Patients with TP53-mutated (TP53 MUT ) MDS/AML are at particularly high risk, yet fewer TP53 MUT patients undergo HCT compared with poor-risk TP53-wild type (TP53 WT ) patients. We hypothesized that TP53 MUT MDS/AML patients have unique risk factors affecting the rate of HCT and thus investigated phenotypic changes that may prevent patients with TP53 MUT MDS/AML from receiving HCT. In this single-center retrospective analysis of outcomes for adults with newly diagnosed MDS or AML (n = 352), HLA typing was used as a surrogate for physician "intent to transplant." Multivariable logistic regression models were used to estimate odds ratios (ORs) for factors associated with HLA typing, HCT, and pretransplantation infections. Multivariable Cox proportional hazards models were used to create predicted survival curves for patients with and those without TP53 mutations. Overall, significantly fewer TP53 MUT patients underwent HCT compared to TP53 WT patients (19% versus 31%; P = .028). Development of infection was significantly associated with decreased odds of HCT (OR, .42; 95% CI, .19 to .90) and worse overall survival (hazard ratio, 1.46; 95% CI, 1.09 to 1.96) in multivariable analyses. TP53 MUT disease was independently associated with increased odds of developing an infection (OR, 2.18; 95% CI, 1.21 to 3.93), bacterial pneumonia (OR, 1.83; 95% CI, 1.00 to 3.33), and invasive fungal infection (OR, 2.64; 95% CI, 1.34 to 5.22) prior to HCT. Infections were the cause of death in significantly more patients with TP53 MUT disease (38% versus 19%; P = .005). With substantially more infections and decreased HCT rates in patients with TP53 mutations, this raises the possibility that phenotypic changes occurring in TP53 MUT disease may affect infection susceptibility in this population and drastically impact clinical outcomes., (Copyright © 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Importance: Prior studies have demonstrated an association between cutaneous chronic graft-vs-host disease (cGVHD) and mortality. Assessment of the prognostic value of different measures of disease severity would assist in risk stratification., Objective: To compare the prognostic value of body surface area (BSA) and National Institutes of Health (NIH) Skin Score on survival outcomes stratified by erythema and sclerosis subtypes of cGVHD., Design, Setting, and Participants: Multicenter prospective cohort study from the Chronic Graft-vs-Host Disease Consortium including 9 medical centers in the US, enrolled from 2007 through 2012 and followed until 2018. Participants were adults and children with a diagnosis of cGVHD requiring systemic immunosuppression and with skin involvement during the study period, who had longitudinal follow-up. Data analysis was performed from April 2019 to April 2022., Exposures: Patients underwent continuous BSA estimation and categorical NIH Skin Score grading of cutaneous cGVHD at enrollment and every 3 to 6 months thereafter., Main Outcomes and Measures: Nonrelapse mortality (NRM) and overall survival (OS), compared between BSA and NIH Skin Score longitudinal prognostic models, adjusted for age, race, conditioning intensity, patient sex, and donor sex., Results: Of 469 patients with cGVHD, 267 (57%) (105 female [39%]; mean [SD] age, 51 [12] years) had cutaneous cGVHD at enrollment, and 89 (19%) developed skin involvement subsequently. Erythema-type disease had earlier onset and was more responsive to treatment compared with sclerosis-type disease. Most cases (77 of 112 [69%]) of sclerotic disease occurred without prior erythema. Erythema-type cGVHD at first follow-up visit was associated with NRM (hazard ratio, 1.33 per 10% BSA increase; 95% CI, 1.19-1.48; P < .001) and OS (hazard ratio, 1.28 per 10% BSA increase; 95% CI, 1.14-1.44; P < .001), while sclerosis-type cGVHD had no significant association with mortality. The model with erythema BSA collected at baseline and first follow-up visits retained 75% of the total prognostic information (from all covariates including BSA and NIH Skin Score) for NRM and 73% for OS, with no statistical difference between prognostic models (likelihood ratio test χ2, 5.9; P = .05). Conversely, NIH Skin Score collected at the same intervals lost significant prognostic information (likelihood ratio test χ2, 14.7; P < .001). The model incorporating NIH Skin Score instead of erythema BSA accounted for only 38% of the total information for NRM and 58% for OS., Conclusions and Relevance: In this prospective cohort study, erythema-type cutaneous cGVHD was associated with increased risk of mortality. Erythema BSA collected at baseline and follow-up predicted survival more accurately than the NIH Skin Score in patients requiring immunosuppression. Accurate assessment of erythema BSA may assist in identifying patients with cutaneous cGVHD at high risk for mortality.

Importance: Hematopoietic cell transplantation (HCT) is a potential cure for hematologic cancer but is associated with a risk of relapse and death. Dynamic biomarkers to predict relapse and inform treatment decisions after HCT are a major unmet clinical need., Objective: To identify a quantitative characteristic of leukocyte-endothelial interactions after HCT and test its associations with patient outcomes., Design, Setting, and Participants: In this prospective single-center cohort study from June 2017 to January 2020, patients of any age, sex, race, and ethnicity who had HCT for hematologic cancer were referred by health care professionals as either suspected of having symptoms or not having symptoms of acute graft-vs-host disease between 25 and 161 days after HCT. Patients underwent noninvasive skin videomicroscopy. Videos of dermal microvascular flow were recorded with a reflectance confocal microscope. Two blinded observers (J.R.P. and Z.Z.) counted leukocytes adherent to and rolling along the vessel wall per hour (A&R). Of 57 enrolled patients, 1 relapsed before imaging and was excluded, resulting in 56 patients included in analyses., Main Outcomes and Measures: Relapse of cancer, relapse-free survival, and overall survival., Results: Among the 56 patients (median age, 59 years; 38 [68%] male) who underwent imaging a median of 40 days after HCT, 21 had high A&R and 35 had low A&R. After correcting for the revised Disease Risk Index, patients with high A&R had higher rates of relapse (hazard ratio [HR], 4.24; 95% CI, 1.32-13.58; P = .02), reduced relapse-free survival (HR, 3.29; 95% CI, 1.26-8.55; P = .02), and reduced overall survival (HR, 3.06, 95% CI, 1.02-9.19; P = .05). These associations were preserved after correcting for possible confounders, steroid treatment, and acute graft-vs-host disease status. In the prognostic adequacy calculation by using Cox models, the new imaging biomarker (A&R) accounted for 82% to 95% of the prognostic information to predict each outcome. By contrast, the best existing clinical predictor routinely available, the revised Disease Risk Index, accounted for 10% to 28% of the prognostic information in the same model., Conclusions and Relevance: In this cohort study, leukocyte-endothelial interactions, visualized directly in skin after HCT, were associated with the patient outcomes of relapse, relapse-free survival, and overall survival. Assessing this dynamic marker could help patients at high risk for relapse who may benefit from interventions, such as early withdrawal of immunosuppression.

Thrombosis is a recognized complication in sickle cell disease (SCD). Allogeneic hematopoietic cell transplantation (allo-HCT) remains the sole curative option for patients with severe SCD phenotypes. Data describing the effects of allo-HCT on recurrent thrombotic events (venous and arterial events) are limited, however. We evaluated 31 patients with SCD who underwent allo-HCT with a median follow-up of 34.5 months (range, 13 to 115) post-transplantation. No patient continued anticoagulation or antiplatelet therapy after allo-HCT. There was an absolute difference of 32% (95% confidence interval [CI], 12.3% to 32.2%; P = .002) in the prevalence of venous thromboembolic (VTE) events before and after allo-HSCT. In addition, there was an absolute difference of 38.5% (95% CI, 10.63 to 45.96; P = .006) in the number of ischemic cerebrovascular accidents (CVAs) occurring before and after allo-HSCT. Patients with severe SCD who undergo allo-HCT are less likely to develop recurrent thrombotic events compared with a control cohort of patients matched for age and genotype (odds ratio, 0.22; 95% CI, 0.058 to 0.83; P = .025). Following curative therapy with allo-HCT, there is a reduction in recurrent arterial and venous thrombosis in patients with severe SCD phenotypes., (Copyright © 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

New-onset post-transplant diabetes mellitus (PTDM) occurs frequently after allogeneic hematopoietic cell transplant (HCT). Although calcineurin inhibitors and corticosteroids are assumed to be the cause for hyperglycemia, patients developing PTDM have elevated fasting C-peptide levels before HCT and before immunosuppressive medications. To determine if PTDM results from established insulin resistance present before transplant, we performed oral glucose tolerance tests (OGTTs) and measured whole body, peripheral, and hepatic insulin sensitivity with euglycemic hyperinsulinemic clamps before and 90 days after HLA-identical sibling donor HCT in 20 patients without pretransplant diabetes. HCT recipients were prospectively followed for the development of new-onset PTDM defined as a weekly fasting blood glucose ≥ 126 mg/dL or random blood glucose ≥ 200 mg/dL. During the first 100 days all patients received calcineurin inhibitors, and 11 individuals (55%) were prospectively diagnosed with new-onset PTDM. PTDM diagnosis preceded corticosteroid treatment. During the pretransplant OGTT, elevated fasting (87 mg/dL versus 101 mg/dL; P = .005) but not 2-hour postprandial glucose levels predicted PTDM diagnosis (P = .648). In response to insulin infusion during the euglycemic hyperinsulinemic clamp, patients developing PTDM had lower whole body glucose utilization (P = .047) and decreased peripheral/skeletal muscle uptake (P = .031) before and after transplant, respectively, when compared with non-PTDM patients. Hepatic insulin sensitivity did not differ. Survival was decreased in PTDM patients (2-year estimate, 55% versus 100%; P = .039). Insulin resistance before HCT is a risk factor for PTDM independent of immunosuppression. Fasting pretransplant glucose levels identified PTDM susceptibility, and peripheral insulin resistance could be targeted for prevention and treatment of PTDM after HCT., (Copyright © 2019 American Society for Blood and Marrow Transplantation. All rights reserved.)

Little is known about the anatomic distribution of cutaneous chronic graft-versus-host disease (cGVHD). Using data from the cGVHD Consortium Improving Outcomes Assessment Study, we describe the frequency and extent of erythema and superficial and deep sclerosis in 8 anatomic sites in patients with incident disease (ie, new cGVHD diagnosis within 3 months of study entry) receiving systemic therapy. Of 339 patients with incident disease, 182 (54%) had skin involvement. When an extremity was involved, the same type of disease was present contralaterally in 92% of cases, revealing a high level of symmetry. As anticipated, erythema was the most common incident feature; however, sclerotic skin involvement at the time of cGVHD diagnosis was more common than has been suggested by previous studies. Erythema occurred in 155 (85%) and sclerosis in 53 (29%) of the patients with skin involvement (46% and 16%, respectively, of the entire cohort of 339 incident cGVHD cases). Erythema was least common on the lower extremities (n = 71; 39% of patients with skin involvement). Moveable sclerosis was rare on the head, neck, and scalp (n = 4; 2%). Deep sclerosis did not occur in this region, and instead was most likely to occur on the upper extremities (n = 14; 8%) and lower extremities (n = 14; 8%). More than one-half of patients with erythema (n = 107; 58.7%) had diffuse involvement (4 or more of 8 sites involved), compared with less than one-third of those with sclerosis (n = 16; 30.2%)., (Copyright © 2018. Published by Elsevier Inc.)

The application of machine learning in medicine has been productive in multiple fields, but has not previously been applied to analyze the complexity of organ involvement by chronic graft- versus -host disease. Chronic graft- versus -host disease is classified by an overall composite score as mild, moderate or severe, which may overlook clinically relevant patterns in organ involvement. Here we applied a novel computational approach to chronic graft- versus -host disease with the goal of identifying phenotypic groups based on the subcomponents of the National Institutes of Health Consensus Criteria. Computational analysis revealed seven distinct groups of patients with contrasting clinical risks. The high-risk group had an inferior overall survival compared to the low-risk group (hazard ratio 2.24; 95% confidence interval: 1.36-3.68), an effect that was independent of graft- versus -host disease severity as measured by the National Institutes of Health criteria. To test clinical applicability, knowledge was translated into a simplified clinical prognostic decision tree. Groups identified by the decision tree also stratified outcomes and closely matched those from the original analysis. Patients in the high- and intermediate-risk decision-tree groups had significantly shorter overall survival than those in the low-risk group (hazard ratio 2.79; 95% confidence interval: 1.58-4.91 and hazard ratio 1.78; 95% confidence interval: 1.06-3.01, respectively). Machine learning and other computational analyses may better reveal biomarkers and stratify risk than the current approach based on cumulative severity. This approach could now be explored in other disease models with complex clinical phenotypes. External validation must be completed prior to clinical application. Ultimately, this approach has the potential to reveal distinct pathophysiological mechanisms that may underlie clusters. Clinicaltrials.gov identifier: NCT00637689 ., (Copyright© 2019 Ferrata Storti Foundation.)

Allogeneic hematopoietic cell transplantation (HCT) patients are at an increased risk of developing central line-associated bloodstream infections (CLABSIs) due to prolonged periods of myelosuppression, immunosuppression, and indwelling catheter days. CLABSIs are among the most serious complications in HCT recipients and can lead to prolonged hospitalizations, intensive care unit admissions, lengthy antimicrobial therapies, and increased mortality. There is a lack of data regarding the incidence and risk factors associated with the development of CLABSIs in the HCT population undergoing outpatient transplantation. This was a single-center, retrospective analysis of adult patients who underwent allogeneic HCT between July 2012 and July 2016 in an outpatient transplant unit at a tertiary academic medical center. The primary outcome was the cumulative incidence of CLABSIs from the date of central line placement through the first 100 days post-transplantation. Secondary outcomes included risk factors for CLABSI, number of hospitalizations due to CLABSI, mortality rate at 6 months post-transplantation, and the cumulative incidence, speciation, and presence of multidrug resistance in identified microorganisms. Three hundred fifty-nine patients underwent allogeneic HCT at Vanderbilt University Medical Center and 352 were included for analysis. The cumulative incidence of CLABSIs was 9%, with the majority occurring within the first 30 days post HCT (67%). The use of a matched unrelated donor (MUD) and/or haploidentical donor (odds ratio, 3.993; 95% confidence interval [CI], 1.329 to 12.001; P = .0136) and use of an ablative conditioning regimen (odds ratio, 2.394; 95% CI, 1.052 to 5.446; P = .0374) were independently associated with development of a CLABSI on multivariate analysis. The most common organism implicated in CLABSI was Staphylococcus epidermidis (34%). Patients who developed a CLABSI had an almost 5 times higher risk of mortality at 6 months post-transplantation compared with patients who did not develop a CLABSI (hazard ratio, 4.932; 95% CI, 2.463 to 9.878; P < .001). There is a low incidence of CLABSIs in patients undergoing HCT in the outpatient setting. Patients who underwent HCT using a MUD or haploidentical donor and received ablative conditioning were at higher risk for developing CLABSIs. Overall mortality at 6 months post-transplantation was higher in patients who developed a CLABSI. Additional prospective studies are needed to confirm these observations., (Published by Elsevier Inc.)

Antithymocyte globulin (ATG) is used as prophylaxis against graft-versus-host disease (GVHD). Current dosing regimens for ATG are empiric and weight-based, and do not account for patient-specific factors. Furthermore, the target of ATG, recipient T cells post-cytotoxic chemotherapy, is not a function of recipient weight. We hypothesized the recipient peripheral blood absolute lymphocyte count (ALC) on the day of ATG administration would interact with the dose of ATG administered to predict transplantation outcomes. We retrospectively analyzed 135 patients who received ATG for GVHD prophylaxis for unrelated allogeneic hematopoietic cell transplantation at 3 different doses: 10 mg/kg, 7.5 mg/kg, and 5 mg/kg. There was no difference in 2-year overall survival (OS) among ATG dosing groups; however, deaths from infectious complications were significantly higher with higher doses of ATG (3.7% versus 19% versus 26.7%; P = .02). Severity of chronic GVHD was lower with higher doses of ATG (28% versus 24% versus 4%; P = .03). In multivariate analysis, the median peripheral blood ALC on day of ATG administration and the total amount of ATG interacted to predict OS (hazard ratio, .09; P = .03). For low recipient ALC (10th percentile, or .56 × 10 2 /µL), a higher total ATG dose was associated with a greater risk of death, whereas for high recipient ALC (90th percentile, or 24.96 × 10 2 /µL), a higher ATG dose was associated with a lower risk of death. Our findings suggest that the interaction between ATG and its target, the recipient lymphocyte, could represent a new paradigm for ATG dosing., (Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) is a somatic mutation associated with poor outcome when treated with chemotherapy alone. In children, hematopoietic stem cell transplantation (HSCT) is recommended, but very limited data on outcome are reported. We determined the outcome of 29 children with FLT3/ITD-positive acute myelogenous leukemia (AML) who underwent allogeneic HSCT in 4 pediatric centers. Eleven patients (38%) received matched related donor hematopoietic stem cells and 18 (62%) received alternative donors. Eighteen patients (62%) received total body irradiation (TBI)-based regimens. No patients experienced transplantation-related mortality. Eleven patients (38%) experienced relapsed disease. The cumulative incidence of relapse at 2 years was 34.7% (95% confidence interval [CI], 20.4% to 54.9%). Two-year disease-free survival (DFS) and overall survival (OS) were 65.3% (95% CI, 45.1% to 79.6%) and 82.2% (95% CI, 58.5% to 91.3%), respectively. There was no difference in the DFS of patients who received transplants from related donors versus the DFS of those who received transplants from alternative donors (hazard ratio [HR], 2.64; 95% CI, .79 to 8.76; P = .10), using univariate analysis. Patients with higher FLT3/ITD ratio at diagnosis had significantly worse DFS (HR, 1.42; 95% CI, 1.04 to 1.93; P = .03). The use of TBI in the preparative regimen was associated with superior DFS (HR, .29; 95% CI, .08 to .99; P = .04) and OS (HR, .07; 95% CI, .01 to .62; P = .002). We conclude that allogeneic HSCT improves DFS and OS in children with FLT3/ITD-positive AML compared with what has been reported in those treated with chemotherapy alone., (Copyright © 2015 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

The optimal healthcare model for follow-up of allogeneic hematopoietic stem cell transplantation (HSCT) recipients after day 100 is not clear. We previously demonstrated that longitudinal follow-up at the transplant center using a multidisciplinary approach is associated with superior survival. Recent data suggest that increased distance from the transplant center is associated with inferior survival. A dedicated long-term transplant clinic (LTTC) was established in 2006 at our center. We hypothesized that geographic distance would not be associated with inferior outcome if patients are followed in the LTTC. We studied 299 consecutive patients who underwent HSCT and established care in an LTTC. The median distance from the transplant center was 118 miles (range, 1 to 1591). The 75th percentile (170 miles) was used as the cut-off to analyze the impact of distance from the center on outcome (219 patients ≤ 75th percentile; 80 patients >75th percentile). The 2 groups were balanced for pretransplant characteristics. In multivariate analyses adjusted for donor type, Center for International Blood and Marrow Transplant Research risk, and transplant regimen intensity, distance from transplant center did not impact outcome. Our study suggests that geographic distance from the transplant center is not associated with inferior outcome when follow-up care is delivered via a dedicated LTTC incorporating well-coordinated multidisciplinary care., (Published by Elsevier Inc.)

Acute GVHD (aGVHD) remains a major source of morbidity after allogeneic hematopoietic cell transplantation. CD30 is a cell-surface protein expressed on certain activated T cells. We analyzed CD30 expression on peripheral blood T-cell subsets and soluble CD30 levels in 26 patients at the time of presentation of aGVHD, before the initiation of treatment, compared with 27 patients after hematopoietic cell transplantation without aGVHD (NONE). Analysis by flow cytometry showed that patients with aGVHD had a greater percentage of CD30 expressing CD8(+) T cells with the difference especially pronounced in the central memory subset (CD8(+)CD45RO(+)CD62L(+)): GVHD median 12.4% (range, 0.8%-33.4%) versus NONE 2.1% (0.7%, 17.5%), P < .001. There were similar levels of CD30 expression in naive T cells, CD4(+) T cells, and regulatory (CD4(+)CD127(low)CD25(+)) T cells. Plasma levels of soluble CD30 were significantly greater in patients with GVHD: median 61.7 ng/mL (range, 9.8-357.1 ng/mL) versus 17.4 (range, 3.7-142.4 ng/mL) in NONE (P < .001). Immunohistochemical analysis of affected intestinal tissue showed many CD30(+) infiltrating lymphocytes present. These results suggest that CD30 expression on CD8(+) T-cell subsets or plasma levels of soluble CD30 may be a potential biomarker for aGVHD. CD30 may also represent a target for novel therapeutic approaches for aGVHD.

Relapse remains a major cause of death after allogeneic hematopoietic cell transplantation (allo-HCT). Graft-versus-tumor effect is primarily mediated by donor T cells. Cytotoxic T lymphocyte antigen-4 (CTLA-4) is a critical inhibitor of T cell proliferation. Single nucleotide polymorphisms (SNPs) in CTLA-4 may affect immune responses. We hypothesized that CTLA-4 SNPs will be associated with disease control after allo-HCT. One hundred sixty-four adult patients with the availability of pretransplantation recipient and donor DNA samples were included in this analysis. Ten tagSNPs of the CTLA-4 gene were identified. Donor CTLA-4 SNP rs4553808 was associated with decreased relapse-free survival (RFS) (P = .019) and overall survival (OS) (P = .033). In multivariable analysis of an additive genetic model, genotype of CTLA-4 SNP rs4553808 was an independent risk factor for inferior RFS (hazard ratio [HR] = 1.73, 95% confidence interval [CI] 1.10-2.71, P = .017) and OS (HR = 1.84, 95% CI 1.13-3.0, P = .015). CTLA-4 SNPs can be used to identify high-risk patient subsets that may benefit from preemptive immunomodulation to decrease relapse rates and improve survival., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Posttransplantation diabetes mellitus (PTDM) is a frequent complication after allogeneic stem cell transplantation (allo-SCT), important for its negative impact on cardiovascular health. Risk factors for PTDM are not well defined. We conducted a prospective study to investigate the risk factors and incidence for PTDM in the first 100 days after allo-SCT. A total of 84 patients completed the study, 60% of whom developed PTDM. In a multivariate logistic regression model, pretransplantation c-peptide level (>3.6 ng/mL; odds ratio [OR], 5.9; 95% confidence interval [CI], 1.77-20.22; P = .004), unrelated donor allo-SCT (OR, 4.3; 95% CI, 1.34-14.2; P = .014), and peak steroid dose >1 mg/kg/day (OR, 5.09; 95% CI, 1.19-23.2; P = .035) were identified as independent predictors of PTDM. In addition, overall survival (OS) was inferior in patients with PTDM compared with those without PTDM (mean survival, 2.26 years vs 2.7 years; P = .021). Pretransplantation c-peptide level greater than the cohort median (>3.6 ng/mL) also was associated with inferior OS (mean, 1.7 years vs 2.9 years; P = .012). In a multivariate Cox proportional hazards model, high-risk disease (hazard ratio [HR], 2.34; 95% CI, 1.09-5.28; P = .029) and pretransplantation c-peptide level >3.6 ng/mL (HR, 1.05; 95% CI, 1.01-1.09; P = .013) were independent predictors of OS when adjusted for systemic steroids and regimen intensity. We suspect that diabetes mellitus in the immediate posttransplantation period may be mediated via an inflammatory pathway that contributes to insulin resistance in the host adipose tissue. Our study is the first to report the risk factors of early PTDM in patients undergoing allo-SCT and identifies pretransplantation c-peptide as an independent predictor of diabetes and survival., (2011 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Chronic graft-versus-host disease (cGVHD) is a severe complication in long-term survivors of allogeneic hematopoietic stem cell transplantation. This disease is challenging to manage clinically due to a lack of validated tools to quantitatively measure skin sclerosis. The current gold standard for measuring skin sclerosis is the NIH Skin Score which has only moderate agreement among clinicians and experts. To more accurately assess skin sclerosis in cGVHD, the Myoton and durometer devices can be used to directly measure biomechanical parameters of the skin. However, the reproducibility of these devices is not known in patients with cGVHD. To determine this reproducibility, three observers independently measured 10 anatomic sites in each of seven patients with sclerotic cGVHD using the Myoton and durometer. Clinical reproducibility was measured by mean pairwise differences (U-statistic) and intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs). Mean pairwise differences, expressed in true physical units, were used to report typical errors for each anatomic site and device. Mean pairwise differences were less than 11% of the average overall values for all five Myoton parameters and durometer hardness. These were lower for Myoton creep (4.1%), relaxation time (4.7%), and frequency (5.1%) than decrement (9.0%), stiffness (10.4%), and durometer hardness (9.0%). Myoton parameters creep, relaxation time, and frequency showed promise for capturing skin biomechanics more accurately than Myoton stiffness, decrement, or durometer hardness. Mean pairwise differences trended highest in the shin and volar forearm and lowest in the dorsal forearm. The interobserver ICC for overall (averaged across all measured body sites of a patient) creep (0.94; 95% CI 0.87–1.00), relaxation time (0.96; 95% CI 0.90–1.00), and frequency (0.95; 95% CI 0.88–1.00), trended higher than that for decrement (0.43; 95% CI 0.00–0.88), stiffness (0.92; 95% CI 0.81–1.00), and durometer hardness (0.82; 95% CI 0.61–1.00). Similar trends were observed in healthy participants. These findings can help clinicians design better studies to assess therapeutic response to new cGVHD treatments and support the interpretation of future measurements. [ABSTRACT FROM AUTHOR]