Antithymocyte Globulin Treatment Research Articles

Significance of absolute neutrophil count before allogeneic hematopoietic stem cell transplantation in adult patients with aplastic anemia.

The impact of absolute neutrophil count (ANC) before allogenic hematopoietic stem cell transplantation (HSCT) on the outcomes for patients with aplastic anemia (AA) remains unclear. We retrospectively evaluated the relationship between ANC before transplantation and patient outcomes, involving 883 adult Japanese patients with AA who underwent allogeneic HSCT as their first transplantation between 2008 and 2020. Patients were divided into three groups based on ANC: 0/µL (n = 116); 1-199 (n = 210); and ≥ 200 (n = 557). In the low ANC groups (ANC < 200), patient age was higher, previous anti-thymocyte globulin (ATG) treatments were infrequent, duration from diagnosis to transplantation was shorter, hematopoietic cell transplantation-comorbidity index (HCT-CI) was higher, ATG-based conditioning was used infrequently, and peripheral blood stem cell from related donor and cord blood were used frequently. In multivariate analysis, patient age, previous ATG treatment, HCT-CI, stem cell source, and ANC before transplantation were significantly associated with 5-year overall survival (OS) ("ANC ≥ 200": 80.3% vs. "ANC 1-199": 71.7% vs. "ANC 0": 64.4%). The cumulative incidence of bacterial infection, invasive fungal disease, and early death before engraftment were significantly higher in the low ANC groups. Among patients with ANC of zero before transplantation, younger patient age, shorter duration from diagnosis to transplantation, HCT-CI of 0, and bone marrow from related donor as stem cell source were significantly associated with better OS. Consequently, ANC before allogeneic HSCT was found to be a significant prognostic factor in adult patients with AA. Physicians should pay attention to ANC before transplantation.

Loss of CD5-positive T-cells following anti-thymocyte globulin treatment.

Loss of CD5-positive T-cells following anti-thymocyte globulin treatment.

Effects of Antithymocyte Globulin, Basiliximab, and Induction-Free Treatment in Living Donor Kidney Transplant Recipients on Tacrolimus-Based Immunosuppression.

Induction treatment in renal transplant is associated with better graft survival. However, intensified immunosuppression is known to cause unwanted side effects such as infection and malignancy. Furthermore, the effects of the routine use of immunosuppressants in low-risk kidney transplant recipients are still not clear. In this study, we assessed the first-year safety and efficacy of induction treatment. We examined first living donor kidney transplant patients who were on tacrolimus based immunosuppression therapy. We formed 3 groups according to the induction status: antithymocyte globulin induction, basiliximab induction, and no induction. We collected outcome data on delayed graft function, graft loss, creatinine levels, estimated glomerular filtration rates, acute rejection episodes, hospitalization episodes, and infection episodes, including cytomegalovirus infection and bacterial infections. We examined a total of 126 patients (age 35 ± 12 years; 65% male). Of them, 25 received antithymocyte globulin, 52 received basiliximab, and 49 did notreceive any induction treatment. We did not observe any statistically significant difference among the 3 groups in terms of acute rejection episodes, delayed graft function, and first-year graft loss. The estimated glomerular filtration rates were similar among the groups. Overall bacterial infectious complications and cytomegalovirus infection showed similar prevalence among all groups. Hospitalization was less common in the induction-free group. In low-risk patients, induction-free regimens could be associated with a better safety profile without compromising graft survival. Therefore, induction treatment may be disregarded in first living donor transplant patients who receive tacrolimusbased triple immunosuppression treatment.

Abstract B041: Understanding T-cell large granular lymphocytic leukemia: Diagnosis and treatment options

Abstract Introduction: T-cell large granular lymphocytic leukemia, or T-LGL leukemia, is rare cancer affecting T-cells and natural killer cells. It is characterized by the abnormal proliferation of mature T-cells expressing specific markers. Standard treatments involve immunosuppressive therapies. Understanding the diagnosis and treatment options is crucial for optimal care. Case Presentation: A 54-year-old male with chronic anemia and iron overload was initially diagnosed with myelodysplastic syndrome (MDS). Vidaza followed treatment with Danazol due to negative MDS and myeloproliferative neoplasm (MPN) results. Concerns of red cell aplasia led to corticosteroid and cyclosporin administration, discontinued during the COVID-19 outbreak. A subsequent biopsy revealed pure red cell aplasia, and the patient was prescribed Cyclosporin and later switched to Danazol. The patient underwent Anti-Thymocyte Globulin (ATG) treatment at a cancer center. A bone marrow biopsy confirmed T-LGL leukemia with abnormal CD8-positive T-cells. PCR analysis confirmed clonal T-cell proliferation. Cytogenetics and mutation analyses were negative. The patient is currently receiving Cyclosporin, prednisone, and Jadenu. Conclusion: This case highlights the challenges in diagnosing and managing T-LGL leukemia, a rare lymphoproliferative disorder. The patient's complex medical history and mimicking of other hematologic disorders underscore the need for a multidisciplinary approach. Individualized therapy based on clinical response is necessary due to limited treatment options. Further research and prospective trials are essential to establish a standard of care. Citation Format: Aliya M. Khan, Kierston R. Patterson, Raj Patel, Sophia Navajas Urisote. Understanding T-cell large granular lymphocytic leukemia: Diagnosis and treatment options [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B041.

Development of a Stacked Ensemble Model for Risk Stratification of Chronic Gvhd after Allogeneic HSCT: Trump Cohort Study

Background Effective risk stratification is vital for selecting donors and developing treatment strategies for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Several pretransplant risk models have been proposed to predict post-transplant patient outcomes from pretransplant risk factors. However, it is still challenging to predict mid-to-long-term prognosis. To establish a novel and user-friendly tool for predicting chronic graft-versus-host disease (cGVHD), non-relapse mortality (NRM) and overall survival (OS), we used a Stacked Ensemble Model (SEM) designed to handle right-censored data and competing risk events (Iwasaki et al., 2021). Methods Using Japanese registry data, the Japanese Transplant Registry Unified Management Program, we analyzed 21,840 patients who underwent their first allo-HSCT between 2010 and 2018 for hematologic malignancies. Of these, 14,430 patients were alive without cGVHD and relapse on day 100 post-transplantation. Primary endpoint was cGVHD and secondary endpoints were NRM and OS. Data were randomly split into the training set (70% of the dataset) and the validation set (30%). We treated patient age and time from diagnosis to transplant as continuous variables and performance status, ABO type matching, sex matching, disease/status groups based on refined Disease Risk Index, Hematopoietic Cell Transplantation-specific Comorbidity Index, usage of total body irradiation, conditioning intensity, T cell depletion in vivo, human leukocyte antigen (HLA) locus matching, the number of HLA mismatching and CMV serostatus as categorical variables. To evaluate predictive accuracy at day 30, 60 and 100 posttransplant, we considered acute graft-versus-host disease (aGVHD) and its treatment, including grade 2 to 4 aGVHD occurrence, grade 3 to 4 aGVHD occurrence, stage of aGVHD before and after treatment, corticosteroid treatment, anti-thymocyte globulin treatment and treatment response of 1 st line therapy for aGVHD. Results The median age of the patients at transplantation was 51 years (inter quartile range (IQR): 39 - 60). The sources of stem cells were HLA-matched related bone marrow (BM) in 967 patients, HLA-matched related peripheral blood (PB) in 1,998 patients, haploidentical BM in 172 patients, haploidentical PB in 778 patients, unrelated BM in 5,539 patients, unrelated PB in 366 patients, and cord blood in 4,237 patients. Myeloablative conditioning was administered in 9,390 patients and reduced-intensity conditioning in 5,040 patients. The most common indication of HSCT was intermediate-risk acute myeloid leukemia (AML) in complete remission (CR, n=3,233) followed by acute lymphoblastic leukemia in first CR (n=2,164) and intermediate-risk AML in non-CR (n=1,618). Median follow-up period of survivors was 2.2 years (IQR: 0.9-4.5). The overall performance of SEM was superior across the endpoints evaluated, cGVHD, NRM and OS, while XGBoost showed a slightly higher C-index for cGVHD, demonstrating its robustness and reliability (Table 1, the C-index for cGVHD/NRM/OS-SEM: 0.567/0.635/0.607, Cox-PH: 0.550/0.624/0.602, Random Survival Forest: 0.555/0.632/0.597, XGBoost: 0.573/0.624/0.604, and Dynamic Deephit: 0.549/0.614/0.589). C-index of SEM for cGVHD, NRM, and OS were gradually improved as time goes by (Table 1, the C-index for cGVHD/NRM/OS: at day 30-0.589/0.643/0.635, at day 60-0.598/0.655/0.640, at day 100-0.598/0.688/0.640). Kaplan-Meier curves 100-day post-transplantation confirmed the accuracy of our predictions, effectively stratifying patients into four risk groups (Figure 1). SHapley Additive Explanations showed contribution of variables for predicting specific outcomes. Grade 3 to 4 aGVHD and stage of aGVHD after treatment influenced non-relapse mortality. Particularly, grade 3 to 4 aGVHD showed significant impact on OS in line with pretransplant risk factors including sex matching, donor source and disease/status groups. Grade 2 to 4 aGVHD and treatment response of 1 st line therapy for aGVHD influenced cGVHD. Conclusion Our study emphasizes the importance of aGVHD events in mid-to-long-term post-transplantation outcomes and presents SEM-based prediction models that account for early-phase post-transplantation events. We are currently developing a user-friendly web application tool for cGVHD, aiming to enhance post-transplant risk stratification and preemptive therapy for cGVHD.

Anti-thymocyte globulin exposure in patients with diffuse cutaneous systemic sclerosis undergoing autologous haematopoietic stem cell transplantation.

Autologous haematopoietic stem cell transplantation improves event-free survival and lung function and reduces skin thickening in patients with progressive diffuse cutaneous systemic sclerosis. Anti-thymocyte globulin is a key lymphoablative constituent of conditioning protocols and is administered in a weight-based dosage. However, whether anti-thymocyte globulin exposure contributes to response to autologous haematopoietic stem cell transplantation and lymphocyte reconstitution in diffuse cutaneous systemic sclerosis patients is unknown. We aimed to explore the relationship between anti-thymocyte globulin exposure, lymphocyte reconstitution and treatment response in diffuse cutaneous systemic sclerosis patients undergoing autologous haematopoietic stem cell transplantation. A retrospective cohort of 15 diffuse cutaneous systemic sclerosis patients undergoing autologous haematopoietic stem cell transplantation was performed. Clinical characteristics and routine laboratory results were retrieved from electronic medical records. Anti-thymocyte globulin concentrations were measured in cryopreserved plasma samples at four time points (day 1 and week 1, 2 and 4) after stem cell reinfusion. Anti-thymocyte globulin exposure was estimated using a validated population pharmacokinetic model. During a median follow-up of 45 months (interquartile range 19-66), 11 (73%) patients had a treatment response, and 4 (27%) were non-responders. Although all patients received the same weight-based anti-thymocyte globulin dosage, 7.5 mg/kg divided over 3 days, anti-thymocyte globulin exposure varied. Anti-thymocyte globulin exposure was higher in responders than in non-responders (163 AU*day/mL (interquartile range 153-183) and 137 AU*day/mL (interquartile range 101-149), respectively, p = .026). Anti-thymocyte globulin exposure was not correlated with lymphocyte reconstitution or infection rate. Weight-based dosing of anti-thymocyte globulin results in variable anti-thymocyte globulin exposure and treatment response across individuals.

Eltrombopag Preserves the Clonogenic Potential of Hematopoietic Stem Cells During Treatment With Antithymocyte Globulin in Patients With Aplastic Anemia.

Aplastic anemia (AA) is frequently caused by a T-cell mediated autoimmune depletion of the hematopoietic stem and progenitor cell (HSPC) compartment. Immunosuppressive therapy (IST) with antithymocyte globulin (ATG) and cyclosporine represents the first-line treatment of AA. One side effect of ATG therapy is the release of proinflammatory cytokines such as interferon-gamma (IFN-γ), which is considered a major factor in the pathogenic autoimmune depletion of HSPC. Recently, eltrombopag (EPAG) was introduced for therapy of refractory AA patients due to its ability to bypass IFN-γ-mediated HSPC inhibition among other mechanisms. Clinical trials have evidenced that EPAG started simultaneously with IST leads to a higher response rate compared with its later administration schedules. We hypothesize that EPAG might protect HSPC from negative effects of ATG-induced release of cytokines. We observed a significant decrease in colony numbers when both healthy peripheral blood (PB) CD34+ cells and AA-derived bone marrow cells were cultured in the presence of serum from patients under ATG treatment, as compared with before treatment. Consistent with our hypothesis, this effect could be rescued by adding EPAG in vitro to both healthy and AA-derived cells. By employing an IFN-γ neutralizing antibody, we also demonstrated that the deleterious early ATG effects on the healthy PB CD34+ compartment were mediated at least partially by IFN-γ. Hence, we provide evidence for the hitherto unexplained clinical observation that concomitant use of EPAG in addition to IST comprising ATG leads to improved response in patients with AA.

Cytokine profiling during conditioning in haploidentical stem cell transplantation and its prognostic impact on early transplant outcomes

Cytokine storm development is a major cause of many transplant-related complications, especially during the conditioning regimen. This study aimed to characterize the cytokine profile and determine its prognostic impact during conditioning in patients undergoing subsequent haploidentical stem cell transplantation. A total of 43 patients were enrolled in this study. Sixteen cytokines associated with cytokine release syndrome (CRS) during anti-thymocyte globulin (ATG) treatment were quantified in patients undergoing haploidentical stem cell transplantation. Thirty-six (83.7%) patients developed CRS during ATG treatment; most of those cases (33/36; 91.7%) were classified as grade 1 CRS, whereas only three (7.0%) developed grade 2 CRS. CRS was observed more frequently on the first (15/43; 34.9%) and second day (30/43; 69.8%) of ATG infusion. No factors were identified that could predict the development of CRS on the first day of ATG treatment. Five of the 16 cytokines (interleukins 6, 8, and 10 (IL-6, IL-8, and IL-10), C-reactive protein (CRP), and procalcitonin (PCT)) were significantly elevated during ATG treatment, although only the level of IL-6, IL-10, and PCT were associated with the severity of CRS. However, neither CRS nor the cytokine levels significantly impacted the development of acute graft-versus-host disease (GVHD) or cytomegalovirus (CMV) infection or affected overall survival.

Bone marrow expression of CD68/CD163 macrophages, IL-17 and FOXP3 cells in aplastic anemia and their relation to prognosis.

The primary mechanism for bone marrow failure in aplastic anemia (AA) is autoimmune hematopoietic stem cell destruction. AA can be cured with antithymocyte globulin (ATG) treatment, and some smaller studies have indicated that the number of regulatory T cells (Tregs) may be predictive of response. Additionally, AA patients appear to have elevated numbers of Th17 cells and bone marrow macrophages, but outcome data are missing. We performed immunohistochemistry on bone marrow biopsies from 121 ATG-treated AA patients and 14 healthy controls, using antibodies against FOXP3 (for Tregs), IL-17 (for Th17), CD68 (for pan-macrophages) and CD163 (for M2 type macrophages) to study their possible relation to ATG response and AA prognosis. AA patients had significantly fewer Tregs and Th17 cells but significantly more macrophages compared with controls. Treg, Th17 and pan-macrophage cell numbers were not associated with ATG response or differences in survival. Patients with higher levels of M2 macrophages had improved 5-year overall survival: 79.6% versus 57.4% (p=.017), and this benefit was primarily seen in AA patients with non-severe disease. We found that Treg and Th17 cell numbers did not predict ATG response or survival, whereas M2 macrophages may be associated with improved survival.

Estimative of costs of two therapeutic schemes for aplastic anemia among young individuals

Introduction: Aplastic anemia (AA) is the deficiency of the production of blood cells, with pancytopenia and hypocellular marrow as a result. Eltrombopag® (EPAG), a synthetic thrombopoietin mimic, showed improvement in bone marrow, CD34 and blood precursor cell counts. Today, it is indicated as first-line therapy, in addition to Immunosuppressive Therapy (IST) with cyclosporine and horse Antithymocyte Globulin (ATG). The aim of this study is to compare costs and results of the main current therapeutic schemes for AA among young individuals. Method: This is a study to estimate costs and results of a therapeutic scheme using EPAG associated with IST and the management of complications in comparison with standard therapy. The protocols used were those of the Ministry of Health and the scheme indicated in the literature for the EPAG. As a basis for calculation, a typical patient was simulated, who would be followed up by a pediatric hematology service in Sergipe, which works as part of the Unified Health System. Result: The cost of Cyclosporine + rabbit ATG treatment for 6 months, based on patient weight, was US$4500. The cost of Cyclosporine + rabbit GAT + EPAG treatment for 6 months was US$182,000. Conclusion: It is concluded, therefore, that drug therapy with EPAG increases the cost of treatment by 40 times. Several studies, however, point to clinical and laboratory gains and increased response rates to the proposed therapy, thus contributing to a better quality of life for a pediatric patient with AA.

Real-world experience of treatment with thrombopoietin receptor agonists in anti-thymocyte globulin-naïve patients with aplastic anemia: an observational retrospective analysis in a single institution

ABSTRACT Objective To explore the efficacy and safety of thrombopoietin receptor agonists (TPO-RAs) without anti-thymocyte globulin (ATG) in ATG-naïve patients with aplastic anemia (AA) in a real-world setting. Methods We retrospectively evaluated treatment outcomes in 45 consecutive ATG-naïve patients with AA who received TPO-RAs between 2017 and 2021 at our hospital. Results ATG ineligibility was due to advanced age (≥ 70 years), n = 22; not recommended under Japanese guidelines due to mild symptoms, n = 13; patient preference, n = 6; uncontrolled heart failure, n = 2; uncontrolled diabetes mellitus, n = 2; chronic renal failure, n = 2; invasive aspergillosis, n = 1. Twenty-eight patients (62%) achieved hematologic response in at least unilineage after 6 months’ treatment, while 38 (84% in unilineage response-eligible patients) and four (25% in trilineage response-eligible patients) patients achieved at least unilineage and trilineage responses, respectively, at any point during the follow-up period. Five patients switched from eltrombopag to romiplostim because of adverse events or lack of efficacy, and two developed hematologic malignancies. Eltrombopag was effective even in elderly ATG-ineligible patients with severe AA. The 2-year overall survival rate was 84.3%, with a median 26.3-month follow-up. Time from diagnosis to eltrombopag treatment initiation tended to affect the response (p = 0.0727), but no factors that significantly predicted hematologic response were identified. Conclusions We found eltrombopag to be effective even in elderly ATG-naïve patients with severe AA, indicating that TPO-RA treatment should be considered in patients ineligible for ATG treatment because of age, complications, or severe AA.

Anti-Thymocyte Globulin Treatment Augments 1,25-Dihydroxyvitamin D3 Serum Levels in Patients Undergoing Hematopoietic Stem Cell Transplantation.

Application of anti-thymocyte globulin (ATG) is a widely used strategy for the prevention of graft-versus-host disease (GvHD). As vitamin D3 serum levels are also discussed to affect hematopoietic stem cell transplantation (HSCT) outcome and GvHD development, we analysed a possible interplay between ATG treatment and serum levels of 25-hydroxyvitamin D3 and 1,25-dihydroxyvitamin D3 in 4 HSCT cohorts with different vitamin D3 supplementation. ATG is significantly associated with higher serum level of 1,25-dihydroxyvitamin D3 around HSCT (day -2 to 7, peri-transplant), however only in patients with adequate levels of its precursor 25-hydroxyvitamin D3. ATG exposure had no impact on overall survival in patients supplemented with high dose vitamin D3, but was associated with higher risk of one-year treatment-related mortality (log rank test p=0.041) in patients with no/low vitamin D3 supplementation. However, the difference failed to reach significance applying a Cox-model regression without and with adjustment for baseline risk factors (unadjusted P=0,058, adjusted p=0,139). To shed some light on underlying mechanisms, we investigated the impact of ATG on 1,25-Dihydroxyvitamin D3 production by human dendritic cells (DCs) in vitro. ATG increased gene expression of CYP27B1, the enzyme responsible for the conversion of 25-hydroxyvitamin D3 into 1,25-dihydroxyvitamin D3, which was accompanied by higher 1,25-dihydroxyvitamin D3 levels in ATG-treated DC culture supernatants. Our data demonstrate a cooperative effect of 25-hydroxyvitamin D3 and ATG in the regulation of 1,25-dihydroxyvitamin D3 production. This finding may be of importance in the context of HSCT, where early high levels of 1,25-dihydroxyvitamin D3 levels have been shown to be predictive for lower transplant related mortality and suggest that vitamin D3 supplementation may especially be important in patients receiving ATG for GvHD prophylaxis.

Anti-thymocyte globulin-mediated immunosenescent alterations of T cells in kidney transplant patients.

Kidney transplant (KT) is the most effective treatment for end-stage renal disease. The immunosuppressant anti-thymocyte globulin (ATG) has been applied for induction therapy to reduce the risk of acute transplant rejection for patients at high immunological risk. Despite its putative role in replicative stress during immune reconstitution, the effects of ATG on T-cell immunosenescent changes remain to be understood. Phenotypic and functional features of senescent T cells were examined by flow cytometry in 116 healthy controls (HC) and 95 KT patients for comparative analysis according to ATG treatment and CMV reactivation. The TCR repertoire was analysed in peripheral blood mononuclear cells (PBMCs) of KT patients. T cells of KT patients treated with ATG (ATG+) show typical immunosenescent features, accumulation of CD28-, CD85j+ or CD57+ T cells, and imbalance of functional T-cell subsets, compared with untreated KT patients (ATG-). Plasma IL-15 and CMV-IgG levels were higher in KT patients than in HCs, and the IL-15 level positively correlated with the frequency of CD28- Tcells in KT patients. ATG+ patients had a higher prevalence of CMV reactivation, which is associated with an increased frequency of CD28- T cells. As a result, ATG+ patients had expanded CMV-specific T cells and decreased TCR diversity. However, proliferation, cytokine-producing capacity and polyfunctionality of T cells were preserved in ATG+ patients. Our findings suggest that ATG treatment contributes to the accumulation of senescent T cells, which may have lifelong clinical implications in KT patients. Thus, these patients require long-term and comprehensive immune monitoring.

Cost-Effectiveness of Low-Dose Antithymocyte Globulin Versus Other Immunotherapies for Treatment of New-Onset Type 1 Diabetes.

Objective: Several immunotherapies have shown efficacy in slowing C-peptide decline in new-onset type 1 diabetes. Although most of these biologic drugs are expensive, they offer the opportunity to reduce downstream disease management costs and risk of complications. The objective of this study is to examine the cost-effectiveness of immunotherapies versus no treatment for patients with new-onset type 1 diabetes. Methods: Using Markov microsimulation modeling and efficacy data from immunotherapy trials, we examined the cost-effectiveness of six immunotherapies for new-onset type 1 diabetes, namely, low-dose (2.5 mg/kg) antithymocyte globulin (ATG), high-dose (6.5 mg/kg) ATG, abatacept, alefacept, rituximab, and teplizumab, versus no treatment. Effectiveness was measured by quality-adjusted life-years (QALYs). Costs were estimated from a health system perspective. Results: Low-dose ATG treatment saves US$10,270, on average, over a patient's lifetime and generates 0.09 additional QALYs compared with no treatment. These cost savings arise as low-dose ATG generates downstream savings in disease management costs that more than offset its cost. In contrast, treatment with other immunotherapies yields smaller QALY gains (0.02-0.05 additional QALYs) and increases lifetime costs by US$9500-US$168,380 relative to no treatment, with incremental cost-effectiveness ratios that exceed the willingness-to-pay threshold of US$100,000 per QALY. Conclusions: Low-dose ATG treatment is both less costly and more effective relative to other immunotherapies and no treatment for new-onset type 1 diabetes.

Antithymocyte Globulin Treatment for Chronic Lung Allograft Dysfunction in Lung Transplant Recipients: Experience From a National Reference Transplant Center

Chronic lung allograft dysfunction (CLAD) is the leading cause of mortality after the first year of transplantation and treatments can have little impact on CLAD progression in some cases. The objective of this study was to evaluate the effectiveness and safety of antithymocyte globulin (ATG) in lung transplant recipients with CLAD. We reviewed all patients from our center that had undergone a lung transplant between 2008 and 2019 and selected those with CLAD who were treated with ATG. The closest lung function (forced expiratory volume in the first second) to the ATG administration was recorded, as well as the values 3, 6, and 12 months before and after treatment. We followed and recorded survival during the 12 months after treatment. A total of 13 patients with CLAD received ATG treatment. A favorable positive response to treatment (improvement or stabilization on lung function) was achieved in half of the patients. Most patients (71%) who responded well to ATG were in CLAD stage 1 to 2. The fall slope of forced expiratory volume in the first second is better after treatment. The median survival was 27 months, and we found a trend toward better survival in early CLAD stages 1 to 2. There were also differences in survival between rapid decliners and nonrapid decliners. ATG treatment could play a role in patient with CLAD who do not respond to conventional therapies. The effect of cytolytic therapy with ATG is clearly better in those patients in early stages, with little effect in those in CLAD stage 3.

The response-guided ATG treatment provides a survival benefit and KPS recovery for patients with steroid refractory acute GVHD: The Nagasaki Transplant Group Experience

Steroid-refractory acute graft-versus-host disease (SR-aGVHD) is a serious complication that negatively affects the prognosis and quality of life of patients who receive allogeneic hematopoietic stem cell transplantation (allo-HSCT). Antithymocyte globulin (ATG) is one of the second-line treatments for SR-aGVHD. We retrospectively evaluated Karnofsky Performance Status (KPS) recovery and clinical response in 11 patients who received the response-guided low-dose ATG treatment for SR-aGVHD after allo-HSCT using alternative donors. The median dose of ATG per cycle was 1.0 mg/kg (range, 1.0–1.25 mg/kg) and the median number of cycles of ATG was 2 (range, 1–4). The overall response rate was 63.6%, and the estimated overall survival rate at 1 year was 63.6%. Two out of seven patients who survived 1 year after the response-guided ATG treatment had KPS of 80 or higher. The remaining 5 patients had KPS of lower than 80 due to moderate chronic GVHD (cGVHD) and/or ≥grade 3 infectious complications. Based on the poor prognosis of patients with SR-aGVHD, the response-guided ATG treatment represents one therapeutic option. The present results also suggest that chronic GVHD and infectious complications after the response-guided ATG treatment were associated with decreased KPS recovery and impaired social function.

Prior antithymocyte globulin therapy and survival in post-transplant lymphoproliferative disorders

Background: Treatment with antithymocyte globulin (ATG) is a well-recognized risk factor for the development of post-transplant lymphoproliferative disorders (PTLD) after solid organ transplantation, but it is unknown how its use affects overall survival after PTLD. Methods: A total of 114 patients with PTLD and available data on immunosuppressive regimen were included from a nation-wide case series of solid organ transplant recipients in Sweden. Prior use of ATG was correlated to clinical features, PTLD subtype, and survival. Results: A total of 47 (41%) patients had received ATG prior to the diagnosis of PTLD. The ATG-treated patients were more likely to be recipients of hearts or lungs, and less likely of kidneys (p < 0.01). They had experienced more acute rejections (p = 0.02). The PTLDs arose earlier, median 2.0 vs. 6.6 years post-transplant (p = 0.002) and were more often situated in the allograft (32% vs. 7%, p < 0.001) in patients with prior ATG vs. no ATG treatment. The PTLDs in the ATG group were more often Epstein–Barr virus-positive (80% vs. 40%, p < 0.001). There were more polymorphic PTLDs (17% vs. 1.5%, p = 0.004) and less T-cell PTLDs (4% vs. 19%, p = 0.02) in the ATG group than in the no ATG group. Diffuse large B-cell lymphoma was equally common in patients with and without prior ATG therapy, but the non-germinal center subtype was more frequent in the ATG group (p = 0.001). In an adjusted Cox proportional hazards regression model, prior ATG treatment and better performance status were associated with superior overall survival, whereas older age, T-cell subtype of PTLD, presence of B symptoms, and elevated lactate dehydrogenase were associated with inferior overall survival. Patients receiving ATG solely as rejection therapy had superior overall survival compared with those receiving ATG as induction therapy or both (p = 0.03). Conclusions: ATG therapy, especially rejection therapy, prior to PTLD development is an independent prognostic factor for superior overall survival after PTLD diagnosis.

Platelet/Lymphocyte ratio independently predicts the outcome of severe aplastic anemia patients treated with antithymocyte globulin.

The aim of this study was to determine the clinical role of platelet/lymphocyte ratio and neutrophil/lymphocyte ratio in severe aplastic anemia patients treated with antithymocyte globulin. The outcomes of consecutive severe aplastic anemia patients treated with rabbit or swine antithymocyte globulin plus cyclosporine (n=159, from January 2012 to December 2018) were analyzed retrospectively. In a total of 159 patients, the actuarial 5-year survival rate was 85.6%. Low platelet/lymphocyte ratio (PLR≤55) was significantly associated with less complications at 1 month and 24 months after the antithymocyte globulin treatment (p=0.048 and 0.028, respectively). The univariate and multivariate analyses revealed that low platelet/lymphocyte ratio was an independent predictor of overall survival (p=0.03 and 0.04, respectively). Patients with low neutrophil/lymphocyte ratio (NLR≤0.18) had shorter survival time, but there was no significant difference (p=0.056). PLR was positively correlated with neutrophil/lymphocyte ratio (r=0.38, p<0.0001) and age (r=0.17, p=0.0379), while it was negatively correlated with IgG level (r=-0.18, p=0.0309). The ratio of CD4/CD8 was significantly higher in low platelet/lymphocyte ratio group (p=0.005). The platelet/lymphocyte ratio reflects the immune abnormality of SAA. Notably, low platelet/lymphocyte ratio is an independently positive prognostic factor for severe aplastic anemia patients treated with antithymocyte globulin.

Impact of Therapy with Anti-Thymocyte Globulin in Heart Transplant Recipients on Acute Cellular Rejection and Readmission for Infection - A Single Center Retrospective Study

Background Approximately 20% of all orthotropic heart transplant (OHT) recipients in the US receive anti-thymocyte globulin (ATG) post-transplant to prevent acute rejection, however use varies between centers. There is lack of prospective multi center clinical trials assessing long-term survival benefit of early ATG treatment including readmission for infections compared with no induction in OHT patients. We aim to review the role of ATG use during the index hospitalization for OHT to prevent acute cellular rejection (ACR) and evaluate the impact of ATG in readmission rates for infection at our center. Hypothesis We hypothesize that therapy with ATG improves freedom from ACR but may result in higher readmission rates for infection. Methods We performed a retrospective cohort study of 98 adults who underwent OHT at a single center from January 2014 to December 2019. Patients without one year follow up and those who underwent heart-kidney transplant were excluded. We compared baseline characteristics and analyzed outcomes between patients with and without ATG administration using standard statistical methods. Unadjusted Kaplan-Meier curves were used to study differences in ACR and hospitalization for infection between patients with and without ATG administration. Results 53 OHT patients received ATG and 45 patients did not. There was no significant difference in death at one year (p=1.0), ACR (p=0.17) or readmission for infection (p=0.35) between the two groups. Patients receiving ATG had delayed date to first ACR (p=0.038), with a median time of first ACR of 100 days versus 26 days post-OHT in the non-ATG group. Conclusion Treatment with ATG during the index hospitalization for OHT delayed the time of first ACR but not the overall burden of rejection in the first year. The rate of freedom from infection was similar in both groups along with overall mortality. As this is a retrospective observation we will analyze the use of ATG in selected patients at high risk for rejection or for renal sparing.

Acute kidney injury with extreme hyperuricemia after antithymocyte globulin treatment in a kidney transplant recipient with underlying aplastic anemia: a case report

BackgroundThe occurrences of hyperuricemia and acute kidney injury after antithymocyte globulin treatment are unusual in kidney transplant recipients. Here, we report a unique case of acute kidney injury with extreme hyperuricemia after antithymocyte globulin treatment in a kidney transplant recipient with underlying aplastic anemia.Case presentationA 40-year-old woman with aplastic anemia who received a kidney transplant 5 years 6 months before presented to our emergency department with complaints of oliguria, generalized edema, and general weakness 6 days after receiving antithymocyte globulin treatment for acute T-cell-mediated rejection. Urinalysis revealed 100 uric acid crystal particles. The blood chemistry test results showed rapid increases in serum creatinine (from 2.86 mg/dL to 5.58 mg/dL) and uric acid levels (from 10.2 mg/dL to 32.7 mg/dL), which suggested acute uric acid nephropathy. Tumor lysis syndrome was suspected to be the cause of the acute uric acid nephropathy; hence, the patient was reevaluated for aplastic anemia. Human leukocyte antigen-DR15 was positive, and flow cytometry revealed a low percentage of glycophosphatidyl inositol-deficient granulocytes (2.9%), which suggested paroxysmal nocturnal hemoglobinuria clones. These findings indicate that the previously diagnosed aplastic anemia had either originally been hypocellular myelodysplastic syndrome (MDS) or later transformed into hypocellular MDS, which is a type of bone marrow failure syndrome.ConclusionsClinicians should consider unexpected tumor lysis syndrome to be the cause of complications after antithymocyte globulin treatment in kidney transplant recipients with underlying bone marrow failure syndrome.