IKAROS gain of function disease: Allogeneic hematopoietic cell transplantation experience and expanded clinical phenotypes

IKAROS, encoded by IKZF1, is a tumor suppressor and a key hematopoietic transcription factor responsible for lymphoid and myeloid differentiation. IKZF1 mutations result in inborn errors of immunity presenting with increased susceptibility to infections, immune dysregulation, and malignancies. In particular, patients carrying IKZF1 gain-of-function (GOF) mutations mostly exhibit symptoms of immune dysregulation and polyclonal plasma cell proliferation. Herein, we describe seven new IKAROS GOF cases from two unrelated families, presenting with novel infectious, immune dysregulation and hematologic diseases. Two of the patients underwent allogeneic hematopoietic cell transplantation (HCT) due to poorly responsive complications. HCT was well-tolerated achieving full engraftment in both patients receiving reduced intensity, matched unrelated donor grafts, with no severe acute or chronic graft-vs-host-disease, and in remission from their diseases 2.5 and 4 years post-HCT, respectively. These results suggest that HCT is a valid and curative option in patients with IKAROS GOF disease and severe clinical manifestations.

Expanded microbiome niches of RAG-deficient patients

The complex interplay between microbiota and immunity is important to human health. To explore how altered adaptive immunity influences the microbiome, we characterize skin, nares, and gut microbiota of patients with recombination-activating gene (RAG) deficiency-a rare genetically defined inborn error of immunity (IEI) that results in a broad spectrum of clinical phenotypes. Integrating de novo assembly of metagenomes from RAG-deficient patients with reference genome catalogs provides an expansive multi-kingdom view of microbial diversity. RAG-deficient patient microbiomes exhibit inter-individual variation, including expansion of opportunistic pathogens (e.g., Corynebacterium bovis, Haemophilus influenzae), and a relative loss of body site specificity. We identify 35 and 27 bacterial species derived from skin/nares and gut microbiomes, respectively, which are distinct to RAG-deficient patients compared to healthy individuals. Underscoring IEI patients as potential reservoirs for viral persistence and evolution, we further characterize the colonization of eukaryotic RNA viruses (e.g., Coronavirus 229E, Norovirus GII) in this patient population.

Evaluation and Management of Deficiency of Adenosine Deaminase 2: An International Consensus Statement

Importance

Deficiency of adenosine deaminase 2 (DADA2) is a recessively inherited disease characterized by systemic vasculitis, early-onset stroke, bone marrow failure, and/or immunodeficiency affecting both children and adults. DADA2 is among the more common monogenic autoinflammatory diseases, with an estimate of more than 35 000 cases worldwide, but currently, there are no guidelines for diagnostic evaluation or management.

Objective

To review the available evidence and develop multidisciplinary consensus statements for the evaluation and management of DADA2.

Evidence Review

The DADA2 Consensus Committee developed research questions based on data collected from the International Meetings on DADA2 organized by the DADA2 Foundation in 2016, 2018, and 2020. A comprehensive literature review was performed for articles published prior to 2022. Thirty-two consensus statements were generated using a modified Delphi process, and evidence was graded using the Oxford Center for Evidence-Based Medicine Levels of Evidence.

Findings

The DADA2 Consensus Committee, comprising 3 patient representatives and 35 international experts from 18 countries, developed consensus statements for (1) diagnostic testing, (2) screening, (3) clinical and laboratory evaluation, and (4) management of DADA2 based on disease phenotype. Additional consensus statements related to the evaluation and treatment of individuals with DADA2 who are presymptomatic and carriers were generated. Areas with insufficient evidence were identified, and questions for future research were outlined.

Conclusions and Relevance

DADA2 is a potentially fatal disease that requires early diagnosis and treatment. By summarizing key evidence and expert opinions, these consensus statements provide a framework to facilitate diagnostic evaluation and management of DADA2.

Abnormal liver tests are not sufficient for diagnosis of hepatic graft-versus-host disease in critically ill patients

Hepatic graft-versus-host disease (HGVHD) contributes significantly to morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Clinical findings and liver biomarkers are neither sensitive nor specific. The relationship between clinical and histologic diagnoses of HGVHD was assessed premortem and at autopsy. Medical records from patients who underwent HSCT at the National Institutes of Health (NIH) Clinical Center between 2000 and 2012 and expired with autopsy were reviewed, and laboratory tests within 45 days of death were divided into 15-day periods. Clinical diagnosis of HGVHD was based on Keystone Criteria or NIH Consensus Criteria, histologic diagnosis based on bile duct injury without significant inflammation, and exclusion of other potential etiologies. We included 37 patients, 17 of whom had a cholestatic pattern of liver injury and two had a mixed pattern. Fifteen were clinically diagnosed with HGVHD, two showed HGVHD on autopsy, and 13 had histologic evidence of other processes but no HGVHD. Biopsy or clinical diagnosis of GVHD of other organs during life did not correlate with HGVHD on autopsy. The diagnostic accuracy of the current criteria was poor (κ = -0.20). A logistic regression model accounting for dynamic changes included peak bilirubin 15 days before death, and an increase from period -30 (days 30 to 16 before death) to period -15 (15 days before death) showed an area under the receiver operating characteristic curve of 0.77. Infection was the immediate cause of death in 68% of patients. In conclusion, liver biomarkers at baseline and GVHD elsewhere are poor predictors of HGVHD on autopsy, and current clinical diagnostic criteria have unsatisfactory performance. Peak bilirubin and cholestatic injury predicted HGVHD on autopsy. A predictive model was developed accounting for changes over time. Further validation is needed.

The Spectrum of the Deficiency of Adenosine Deaminase 2: An Observational Analysis of a 60 Patient Cohort

The deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessively inherited disease that has undergone extensive phenotypic expansion since being first described in patients with fevers, recurrent strokes, livedo racemosa, and polyarteritis nodosa in 2014. It is now recognized that patients may develop multisystem disease that spans multiple medical subspecialties. Here, we describe the findings from a large single center longitudinal cohort of 60 patients, the broad phenotypic presentation, as well as highlight the cohort’s experience with hematopoietic cell transplantation and COVID-19. Disease manifestations could be separated into three major phenotypes: inflammatory/vascular, immune dysregulatory, and hematologic, however, most patients presented with significant overlap between these three phenotype groups. The cardinal features of the inflammatory/vascular group included cutaneous manifestations and stroke. Evidence of immune dysregulation was commonly observed, including hypogammaglobulinemia, absent to low class-switched memory B cells, and inadequate response to vaccination. Despite these findings, infectious complications were exceedingly rare in this cohort. Hematologic findings including pure red cell aplasia (PRCA), immune-mediated neutropenia, and pancytopenia were observed in half of patients. We significantly extended our experience using anti-TNF agents, with no strokes observed in 2026 patient months on TNF inhibitors. Meanwhile, hematologic and immune features had a more varied response to anti-TNF therapy. Six patients received a total of 10 allogeneic hematopoietic cell transplant (HCT) procedures, with secondary graft failure necessitating repeat HCTs in three patients, as well as unplanned donor cell infusions to avoid graft rejection. All transplanted patients had been on anti-TNF agents prior to HCT and received varying degrees of reduced-intensity or non-myeloablative conditioning. All transplanted patients are still alive and have discontinued anti-TNF therapy. The long-term follow up afforded by this large single-center study underscores the clinical heterogeneity of DADA2 and the potential for phenotypes to evolve in any individual patient.

Increased Activity of a NK-Specific CAR-NK Framework Targeting CD3 and CD5 for T-Cell Leukemias

Simple Summary

Chimeric antigen receptors (CAR) can redirect the activity of NK cells to target T-cell malignancies. Our results identify that recognition of CD5 molecules in malignant T cells by the CAR leads to improved antitumor response compared to targeting CD3, due to strong downregulation of the CD3 antigen after CD3-CAR treatment. We have also identified that a specific CAR-NK framework has superior activity than a CAR-T framework on NK effector cells.

Abstract

NK effector cells expressing a CAR construct may be used to target T-lineage markers. In this work, we compared the activity of a NK-specific CAR-NK and a CAR-T framework when expressed on NK effector cells to target CD3 and CD5 in T-cell malignancies. Our results show that CD3-CAR-T is more active than CD5-CAR-T to eliminate malignant T cells in vitro, however, CD3-CAR-T were less efficient to eliminate tumor cells in vivo, while CD5-CAR-T had antitumor activity in a diffuse xenograft model. Lack of in vivo efficacy correlated with downregulation of CD3 levels in target T cells after coculture with CD3-CAR effector cells. The CAR-NK framework greatly improved the efficacy of CARs leading to increased degranulation, cytokine secretion and elimination of the tumor xenograft by CD5-CAR-NK effector cells. Finally, all CAR constructs were similarly effective to eliminate malignant T cells in vitro. Our results show that the NK-CAR framework improves the activity of CARs in NK cells and that CD5 would be a better target than CD3 for T-cell malignancies, as dynamic downregulation of target expression may affect in vivo efficacy.

Post-Transplantation Cyclophosphamide Is Associated with an Increase in Non-Cytomegalovirus Herpesvirus Infections in Patients with Acute Leukemia and Myelodysplastic Syndrome

The use of post-transplantation cyclophosphamide (PTCy) for graft-versus-host disease (GVHD) prophylaxis in recipients of haploidentical and fully matched transplantations is on the increase. Published studies have reported an increased incidence of cytomegalovirus (CMV) infection with the use of PTCy. Limited data exist on the incidence and outcomes of infection with non-CMV herpesviruses (NCHV) in this setting. The aim of this study was to evaluate the cumulative incidence of NCHV infections and the association of NCHV infections with transplantation-specific outcomes in recipients of haploidentical transplantation with PTCy (HaploCy), matched sibling donor transplantation with PTCy (SibCy), and matched sibling donor transplantation with calcineurin inhibitor-based prophylaxis (SibCNI). We hypothesized that, like CMV infection, HaploCy recipients of also will have a higher risk of NCHV infections. Using the Center for International Blood and Marrow Transplantation Research database, we analyzed 2765 patients (HaploCy, n = 757; SibCNI, n = 1605; SibCy, n = 403) who had undergone their first hematopoietic stem cell transplantation (HCT) between 2012 and 2017 for acute myelogenous leukemia, acute lymphoblastic leukemia, or myelodysplastic syndrome. The cumulative incidence of NCHV at 6 months post-NCT was 13.9% (99% confidence interval], 10.8% to 17.3%) in the HaploCy group, 10.7% (99% CI, 7.1% to 15%) in the SibCy group, and 5.7% (99% CI, 4.3% to 7.3%) in the Sib CNI group (P < .001). This was due primarily to a higher frequency of human herpesvirus 6 viremia reported in patients receiving PTCy. The incidence of Epstein-Barr viremia was low in all groups, and no cases of post-transplantation lymphoproliferative disorder were seen in either PTCy group. The incidence of NCHV organ disease was low in all 3 cohorts. The development of NCHV infection was associated with increased treatment-related mortality, particularly in the HaploCy group. There was no association with the development of GVHD, relapse, or disease-free survival. Patients in PTCy cohorts who did not develop NCHV infection had lower rates of cGVHD. This study demonstrates that the use of PTCy is associated with an increased risk of NCHV infection. The development of NCHV infection was associated with increased nonrelapse mortality, especially in the HaploCy group. Prospective trials should consider viral surveillance strategies in conjunction with assessment of immune reconstitution for a better understanding of the clinical relevance of viral reactivation in different HCT settings.

Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients

PURPOSE

Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2.

METHODS

We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS).

RESULTS

Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT.

CONCLUSION

HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency.

CLINICAL IMPLICATIONS

HCT is a definitive cure for DADA2 with > 95% survival.

Treatment of Relapsing HPV Diseases by Restored Function of Natural Killer Cells

Human papillomavirus (HPV) infections underlie a wide spectrum of both benign and malignant epithelial diseases. In this report, we describe the case of a young man who had encephalitis caused by herpes simplex virus during adolescence and currently presented with multiple recurrent skin and mucosal lesions caused by HPV. The patient was found to have a pathogenic germline mutation in the X-linked interleukin-2 receptor subunit gamma gene (IL2RG), which was somatically reverted in T cells but not in natural killer (NK) cells. Allogeneic hematopoietic-cell transplantation led to restoration of NK cytotoxicity, with normalization of the skin microbiome and persistent remission of all HPV-related diseases. NK cytotoxicity appears to play a role in containing HPV colonization and the ensuing HPV-related hyperplastic or dysplastic lesions. (Funded by the National Institutes of Health and the Herbert Irving Comprehensive Cancer Center Flow Cytometry Shared Resources.).

Posttransplant cyclophosphamide is associated with increased cytomegalovirus infection: a CIBMTR analysis

Prior studies suggest increased cytomegalovirus (CMV) infection after haploidentical donor transplantation with posttransplant cyclophosphamide (HaploCy). The role of allograft source and posttransplant cyclophosphamide (PTCy) in CMV infection is unclear. We analyzed the effect of graft source and PTCy on incidence of CMV infection, and effects of serostatus and CMV infection on transplant outcomes. We examined patients reported to the Center for International Blood and Marrow Transplantation Research between 2012 and 2017 who had received HaploCy (n = 757), matched related (Sib) with PTCy (SibCy, n = 403), or Sib with calcineurin inhibitor-based prophylaxis (SibCNI, n = 1605). Cumulative incidences of CMV infection by day 180 were 42%, 37%, and 23%, respectively (P < .001). CMV disease was statistically comparable. CMV infection risk was highest for CMV-seropositive recipients (R+), but significantly higher in PTCy recipients regardless of donor (HaploCy [n = 545]: hazard ratio [HR], 50.3; SibCy [n = 279]: HR, 47.7; SibCNI [n = 1065]: HR, 24.4; P < .001). D+/R- patients also had increased risk for CMV infection. Among R+ or those developing CMV infection, HaploCy had worse overall survival and nonrelapse mortality. Relapse was unaffected by CMV infection or serostatus. PTCy was associated with lower chronic graft-versus-host disease (GVHD) overall, but CMV infection in PTCy recipients was associated with higher chronic GVHD (P = .006). PTCy, regardless of donor, is associated with higher incidence of CMV infection, augmenting the risk of seropositivity. Additionally, CMV infection may negate the chronic GVHD protection of PTCy. This study supports aggressive prevention strategies in all receiving PTCy.

International retrospective study of allogeneic hematopoietic cell transplantation for activated PI3K-delta syndrome

Background:

Activated phosphoinositide 3-kinase delta syndrome (APDS) is a combined immunodeficiency with a heterogeneous phenotype considered reversible by allogeneic hematopoietic cell transplantation (HCT).

Objectives:

This study sought to characterize HCT outcomes in APDS.

Methods:

Retrospective data were collected on 57 patients with APDS1/2 (median age, 13 years; range, 2–66 years) who underwent HCT.

Results:

Pre-HCT comorbidities such as lung, gastrointestinal, and liver pathology were common, with hematologic malignancy in 26%. With median follow-up of 2.3 years, 2-year overall and graft failure–free survival probabilities were 86% and 68%, respectively, and did not differ significantly by APDS1 versus APDS2, donor type, or conditioning intensity. The 2-year cumulative incidence of graft failure following first HCT was 17% overall but 42% if mammalian target of rapamycin inhibitor(s) (mTORi) were used in the first year post-HCT, compared with 9% without mTORi. Similarly, 2-year cumulative incidence of unplanned donor cell infusion was overall 28%, but 65% in the context of mTORi receipt and 23% without. Phenotype reversal occurred in 96% of evaluable patients, of whom 17% had mixed chimerism. Vulnerability to renal complications continued post-HCT, adding new insights into potential nonimmunologic roles of phosphoinositide 3-kinase not correctable through HCT.

Conclusions:

Graft failure, graft instability, and poor graft function requiring unplanned donor cell infusion were major barriers to successful HCT. Post-HCT mTORi use may confer an advantage to residual host cells, promoting graft instability. Longer-term post-HCT follow-up of more patients is needed to elucidate the kinetics of immune reconstitution and donor chimerism, establish approaches that reduce graft instability, and assess the completeness of phenotype reversal over time.

Rebound and overshoot of donor-specific antibodies to human leukocyte antigens (HLA) during desensitization with plasma exchanges in hematopoietic progenitor cell transplantation: A case report

BACKGROUND

Donor-specific antibodies (DSA) to HLA have been associated with graft loss in hematopoietic progenitor cell (HPC) transplantation. Limited data associate therapeutic plasma exchange (TPE) with desensitization and successful engraftment. We report an attempt of desensitization and observed overshooting of DSA during transplantation.

CASE REPORT AND RESULTS

A 27-year-old female with cutaneous T cell lymphoma was scheduled for HPC transplantation from her HLA-haploidentical half-sister, who carried the HLA-DRB1*13:03:01 allele. The patient had the corresponding DSA. Lacking an alternative donor option at the time, we attempted a desensitization approach by immunosuppression with tacrolimus and mycophenolate mofetil (MMF). Unexpectedly, DSA increased from a mean fluorescence intensity (MFI) of 1835 on day -63 to 9008 on day -7. The MFI increased further during 3 TPE procedures and intravenous immunoglobulin (IVIG) until day -1. After transplantation, the DSA remained elevated despite 2 more TPE/IVIG procedures and graft-versus-host disease prophylaxis with high-dose cyclophosphamide, sirolimus, and MMF. Flow cytometric crossmatch, initially negative, turned positive after transplantation. Primary graft failure occurred and was attributed to antibody-mediated rejection. A second transplantation from a 7/8 HLA-matched unrelated donor, not carrying DRB1*13:03 allele, resulted in successful engraftment.

CONCLUSION

Unexpected and rapid increases of a DSA can occur despite the use of current desensitization approaches. This is problematic when conditioning has already started, as such increases are unlikely to be overcome by TPE or other interventions for desensitization. Overshoot of DSA in HPC transplantation has rarely been reported. Its cause remains unclear and can include underlying disease, immunotherapy, chemotherapy, or TPE.

Immune Reconstitution Inflammatory Syndrome as a Posttransplantation Complication in Primary Immunodeficiency With Disseminated Mycobacterium avium

Patients with primary immunodeficiencies undergoing allogeneic hematopoietic cell transplantation (HCT) for difficult-to-control infections can experience immune reconstitution inflammatory syndrome (IRIS) following engraftment. In 3 patients with post-HCT IRIS related to mycobacterial infection, in vitro data demonstrate the emergence of pathogen-specific immune responses and a concomitant rise in plasma inflammatory markers.

Induction immunosuppression and the risk of incident malignancies among older and younger kidney transplant recipients: A prospective cohort study

BACKGROUND

Older (≥65) KT recipients differ from their younger counterparts in their immune response to immunosuppression (IS) and may have a different risk of malignancy after receiving induction.

METHODS

We identified 66 700 adult KT recipients treated with anti-thymocyte globulin (ATG) (n = 40 443) or interleukin-2 receptor antagonist (IL-2RA) (n = 26 327) induction (1/1/1999-12/31/2014) using USRDS/Medicare data. We estimated the risk of first-diagnosed post-KT malignancy associated with induction (ATG vs. IL-2RA) using Cox proportional hazard models. We then tested whether these risks differed between older and younger recipients (Wald test for interaction). Models incorporated inverse probability of treatment weights to adjust for confounders.

RESULTS

The 3-year cumulative incidences of any diagnosed malignancy were 11.5%. ATG was associated with a higher malignancy risk (HR = 1.12, 95%CI:1.06-1.18). This association differed (p_interaction  = 0.04) between younger (HR = 1.12, 95%CI:1.06-1.18) and older recipients (HR = 1.03, 95%CI:0.96-1.09). ATG was also associated with higher risk of skin (HR = 1.18, 95%CI:1.08-1.29), lung (HR = 1.24, 95%CI:1.05-1.47), and ovary malignancies (HR = 1.94, 95%CI:1.08-3.48). However, only the association of ATG with post-KT skin malignancy differed (p_interaction  = 0.01) between younger (HR = 1.18; 95%CI:1.08-1.29) and older (HR = 1.01; 95%CI:0.93-1.09) recipients.

CONCLUSIONS

Compared with IL-2RA induction, ATG was associated with elevated post-KT malignancy risk but only among younger recipients. Transplant centers may need to tailor induction IS for younger recipients to mitigate malignancy risk.

Successful Matched Related Bone Marrow Transplantation in a Patient with Autosomal Dominant Interferon Gamma Receptor 1 Deficiency

This is a report of a successful bone marrow transplant in an IFN-γR1 patient with progressive mycobacterial infection.

PURPOSE

Hematopoietic cell transplant in patients with interferon gamma receptor deficiencies has been fraught with challenges, not the least of which is failure of engraftment and infectious complications.

METHODS

This is a report of a successful hematopoietic cell transplant in an actively infected patient of advanced age.

RESULTS

This case report shows successful engraftment and resolution of infection posttransplant using a matched related donor in a single institution.

CONCLUSION

A successful curative HCT despite persistent, disseminated, nontuberculous mycobacterial infection in a patient with AD-IFNγR1 suggests that this approach, while difficult, may be useful in other patients with otherwise refractory disease.

Prospective Study of a Novel, Radiation-Free, Reduced-Intensity Bone Marrow Transplantation Platform for Primary Immunodeficiency Diseases

Allogeneic blood or marrow transplantation (BMT) is a potentially curative therapy for patients with primary immunodeficiency (PID). Safe and effective reduced-intensity conditioning (RIC) approaches that are associated with low toxicity, use alternative donors, and afford good immune reconstitution are needed to advance the field. Twenty PID patients, ranging in age from 4 to 58 years, were treated on a prospective clinical trial of a novel, radiation-free and serotherapy-free RIC, T-cell-replete BMT approach using pentostatin, low-dose cyclophosphamide, and busulfan for conditioning with post-transplantation cyclophosphamide-based graft-versus-host-disease (GVHD) prophylaxis. This was a high-risk cohort with a median hematopoietic cell transplantation comorbidity index of 3. With median follow-up of survivors of 1.9 years, 1-year overall survival was 90% and grade III to IV acute GVHD-free, graft-failure-free survival was 80% at day +180. Graft failure incidence was 10%. Split chimerism was frequently observed at early post-BMT timepoints, with a lower percentage of donor T cells, which gradually increased by day +60. The cumulative incidences of grade II to IV and grade III to IV acute GVHD (aGVHD) were 15% and 5%, respectively. All aGVHD was steroid responsive. No patients developed chronic GVHD. Few significant organ toxicities were observed. Evidence of phenotype reversal was observed for all engrafted patients, even those with significantly mixed chimerism (n = 2) or with unknown underlying genetic defect (n = 3). All 6 patients with pre-BMT malignancies or lymphoproliferative disorders remain in remission. Most patients have discontinued immunoglobulin replacement. All survivors are off immunosuppression for GVHD prophylaxis or treatment. This novel RIC BMT approach for patients with PID has yielded promising results, even for high-risk patients.

Lower Graft-versus-Host Disease and Relapse Risk in Post-Transplant Cyclophosphamide-Based Haploidentical versus Matched Sibling Donor Reduced-Intensity Conditioning Transplant for Hodgkin Lymphoma

Classic Hodgkin lymphoma (cHL) patients with relapsed or refractory disease may benefit from allogeneic hematopoietic cell transplantation (allo-HCT), but many lack a matched sibling donor (MSD). Herein, we compare outcomes of 2 reduced-intensity conditioning (RIC) HCT platforms in cHL: T cell-replete related donor haploidentical (haplo) HCT with a post-transplant cyclophosphamide (PTCy)-based approach versus an MSD/calcineurin inhibitor (CNI)-based approach. The study included 596 adult patients who underwent a first RIC allo-HCT for cHL between 2008 and 2016 using either a haplo-PTCy (n = 139) or MSD/CNI-based (n = 457) approach. Overall survival (OS) was the primary endpoint. Secondary endpoints included acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD), nonrelapse mortality (NRM), relapse/progression, and progression-free survival (PFS). On multivariate analysis, there was no significant difference between haplo/PTCy and MDS/CNI-based approaches in terms of OS (hazard ratio [HR], 1.07; 95% confidence interval [CI], .79 to 1.45; P = .66) or PFS (HR, .86; 95% CI, .68 to 1.10; P = .22). Haplo/PTCy was associated with a significantly higher risk of grades II to IV aGVHD (odds ratio [OR], 1.73, 95% CI, 1.16 to 2.59; P = .007), but the risk of grades III to IV aGVHD was not significantly different between the 2 cohorts (OR, .61; 95% CI, .29 to 1.27; P = .19). The haplo/PTCy platform provided a significant reduction in cGVHD risk (HR, .45; 95% CI, .32 to .64; P < .001), and a significant reduction in relapse risk (HR, .74; 95% CI, .56 to .97; P = .03). There was a statistically nonsignificant trend toward higher NRM with a haplo/PTCy approach (HR, 1.65; 95% CI, .99 to 2.77; P = .06). Haplo/PTCy-based approaches are associated with lower incidences of cGVHD and relapse, with PFS and OS outcomes comparable with MSD/CNI-based approaches. There was a leaning toward higher NRM with a haplo/PTCy-based platform. These data show that haplo/PTCy allo-HCT in cHL results in survival comparable with MSD/CNI-based allo-HCT.

Outcomes of Related and Unrelated Donor Searches Among Patients with Primary Immunodeficiency Diseases Referred for Allogeneic Hematopoietic Cell Transplantation

Patients with primary immunodeficiencies (PIDs) are potentially cured by allogeneic hematopoietic cell transplantation (HCT). The spectrum of PIDs has expanded greatly beyond those that present in infancy or are diagnosed on newborn screening and require urgent, preemptive HCT. Many PID diagnoses are now made later in life, and the role of HCT is only considered for severe disease manifestations; in these cases, the kinetics and goals of a donor search may be different than for severe combined immunodeficiency. Across all PIDs, related donor searches have the additional selection factor of the inherited disease, and such searches may yield more limited options than searches for patients with hematologic malignancies; thus, unrelated donor options often become more critical in these patients. We retrospectively evaluated the outcomes of donor searches among patents with PIDs referred for HCT at the National Institutes of Health, where the minimum patient age for evaluation is 3 years and where donor options include matched sibling donors or matched related donors, HLA-haploidentical (haplo), or 7-8/8 HLA matched unrelated donors (mMUDs/MUDs). Patient (n = 161) and donor demographics, MUD search results, HLA typing, pedigrees, mutation testing, and donor selection data were collected. The National Marrow Donor Program HapLogic 8/8 HLA match algorithm was used to predict the likelihood of a successful MUD search and categorized as very good, good, fair, poor, very poor, or futile per the Memorial Sloan Kettering Cancer Center (MSKCC) Search Prognosis method. There were significant differences by PID mode of inheritance in patient age, disposition (receipt of HCT or not), donor source, and donor relatedness. A related or unrelated donor option could be identified for 94% of patients. Of living first-degree relatives (median, 3; range, 0 to 12 per patient), a median of 1 donor remained for autosomal dominant and X-linked (XL) diseases after HLA typing, mutation testing, and other exclusions, and a median of 2 donors remained for autosomal recessive (AR) diseases. Among patients with a PID of known mode of inheritance (n = 142), the best related donor was haplo for 99 (70%) patients, with 56 (39%) haplos age 40 years or older and 5 (4%) second-degree haplos; 13 (9%) had no family donor options. The best related donor was a heterozygote/asymptomatic carrier of the PID mutation in 36 (49%) patients with AR or XL disease (n = 73). Among patients with MUD search performed (n = 139), 53 (38%) had very poor/futile 8/8 MUD searches, including 6 (32%) of those with unknown PID mutation and therefore no family donor options. The MSKCC Search Prognosis was less favorable for those of non-European ancestry compared with European ancestry (P = .002). Most patients of Hispanic or African ancestry had very poor/futile MUD searches, 71% and 63%, respectively. No HCT recipients with very poor/futile MUD searches (n = 38) received 8/8 MUD grafts. Alternative donor options, including haplo and unrelated donors, are critical to enable HCT for patients with PIDs. MUD search success remains low for those of non-European ancestry, and this is of particular concern for patients with PIDs caused by an unknown genetic defect. Among patients with PIDs, related donor options are reduced and haplos age 40 years and older and/or mutation carriers are often the best family option.

T Cells Genetically Modified to Express an Anti-B-Cell Maturation Antigen Chimeric Antigen Receptor Cause Remissions of Poor-Prognosis Relapsed Multiple Myeloma

Purpose Therapies with novel mechanisms of action are needed for multiple myeloma (MM). T cells can be genetically modified to express chimeric antigen receptors (CARs), which are artificial proteins that target T cells to antigens. B-cell maturation antigen (BCMA) is expressed by normal and malignant plasma cells but not normal essential cells. We conducted the first-in-humans clinical trial, to our knowledge, of T cells expressing a CAR targeting BCMA (CAR-BCMA). Patients and Methods Sixteen patients received 9 × 10⁶ CAR-BCMA T cells/kg at the highest dose level of the trial; we are reporting results of these 16 patients. The patients had a median of 9.5 prior lines of MM therapy. Sixty-three percent of patients had MM refractory to the last treatment regimen before protocol enrollment. T cells were transduced with a γ-retroviral vector encoding CAR-BCMA. Patients received CAR-BCMA T cells after a conditioning chemotherapy regimen of cyclophosphamide and fludarabine. Results The overall response rate was 81%, with 63% very good partial response or complete response. Median event-free survival was 31 weeks. Responses included eradication of extensive bone marrow myeloma and resolution of soft-tissue plasmacytomas. All 11 patients who obtained an anti-MM response of partial response or better and had MM evaluable for minimal residual disease obtained bone marrow minimal residual disease-negative status. High peak blood CAR⁺ cell levels were associated with anti-MM responses. Cytokine-release syndrome toxicities were severe in some cases but were reversible. Blood CAR-BCMA T cells were predominantly highly differentiated CD8⁺ T cells 6 to 9 days after infusion. BCMA antigen loss from MM was observed. Conclusion CAR-BCMA T cells had substantial activity against heavily treated relapsed/refractory MM. Our results should encourage additional development of CAR T-cell therapies for MM.

Comparable composite endpoints after HLA-matched and HLA-haploidentical transplantation with post-transplantation cyclophosphamide

Composite endpoints that not only encompass mortality and relapse, but other critical post-transplant events such as graft-versus-host disease, are being increasingly utilized to quantify survival without significant morbidity after allogeneic blood or marrow transplantation. High-dose, post-transplantation cyclophosphamide reduces severe graft-versus-host disease with allogeneic marrow transplantation, making composite endpoints after this management particularly interesting. We retrospectively analyzed 684 adults with hematologic malignancies who received T-cell-replete bone marrow grafts and cyclophosphamide after myeloablative HLA-matched related (n=192) or unrelated (n=120), or non-myeloablative HLA-haploidentical (n=372) donor transplantation. The median follow up was 4 (range, 0.02-11.4) years. Graft-versus-host disease-free, relapse-free survival was defined as the time after transplantation without grade III-IV acute graft-versus-host disease, chronic graft-versus-host disease requiring systemic treatment, relapse, or death. Chronic graft-versus-host disease-free, relapse-free survival was defined as the time after transplantation without moderate or severe chronic graft-versus-host disease, relapse, or death. One-year graft-versus-host disease-free, relapse-free survival and chronic graft-versus-host disease-free, relapse-free survival estimates were, respectively, 47% (95% CI: 41-55%) and 53% (95% CI: 46-61%) after myeloablative HLA-matched related, 42% (95% CI: 34-52%) and 52% (95% CI: 44-62%) after myeloablative HLA-matched unrelated, and 45% (95% CI: 40-50%) and 50% (95% CI: 45-55%) after non-myeloablative HLA-haploidentical donor transplantation. In multivariable models, there were no differences in graft-versus-host disease-free, or chronic graft-versus-host disease-free, relapse-free survival after either myeloablative HLA-matched unrelated or non-myeloablative HLA-haploidentical, compared with myeloablative HLA-matched related donor transplantation. Although limited by inclusion of dissimilar cohorts, we found that post-transplantation cyclophosphamide-based platforms yield comparable composite endpoints across conditioning intensity, donor type, and HLA match.

Human Herpesvirus 8-Related Primary Effusion Lymphoma After Liver Transplantation

Primary effusion lymphoma is a rare subclass of non-Hodgkin lymphoma associated with human herpesvirus 8 infection and principally seen in human immunodeficiency virus-positive patients. We report on the case of a 72-year-old human immunodeficiency virus-negative male with a hepatic transplant 10 years prior, who presented with a symptomatic right-sided pleural effusion and was found to have primary effusion lymphoma by flow cytometric and cytopathologic examination. Immunohistochemistry of his lymphoma cells was positive for human herpesvirus 8. Both he and his donor had no identifiable risk factors for human herpesvirus 8 infection. The patient was intolerant of antiviral therapy and chemotherapy, dying 7 months after diagnosis. Posttransplant primary effusion lymphoma is exceedingly rare and carries a very poor prognosis. Individualized treatment strategies are necessary given the scant body of published literature with guidance based solely on case reports.

Gray zone lymphoma with features intermediate between classical Hodgkin lymphoma and diffuse large B-cell lymphoma: characteristics, outcomes, and prognostication among a large multicenter cohort

Gray zone lymphoma (GZL) with features between classical Hodgkin lymphoma and diffuse large B-cell lymphoma (DLBCL) is a recently recognized entity reported to present primarily with mediastinal disease (MGZL). We examined detailed clinical features, outcomes, and prognostic factors among 112 GZL patients recently treated across 19 North American centers. Forty-three percent of patients presented with MGZL, whereas 57% had non-MGZL (NMGZL). NMGZL patients were older (50 versus 37 years, P = 0.0001); more often had bone marrow involvement (19% versus 0%, P = 0.001); >1 extranodal site (27% versus 8%, P = 0.014); and advanced stage disease (81% versus 13%, P = 0.0001); but they had less bulk (8% versus 44%, P = 0.0001), compared with MGZL patients. Common frontline treatments were cyclophosphamide-doxorubicin-vincristine-prednisone +/- rituximab (CHOP+/-R) 46%, doxorubicin-bleomycin-vinblastine-dacarbazine +/- rituximab (ABVD+/-R) 30%, and dose-adjusted etoposide-doxorubicin-cyclophosphamide-vincristine-prednisone-rituximab (DA-EPOCH-R) 10%. Overall and complete response rates for all patients were 71% and 59%, respectively; 33% had primary refractory disease. At 31-month median follow-up, 2-year progression-free survival (PFS) and overall survival rates were 40% and 88%, respectively. Interestingly, outcomes in MGZL patients seemed similar compared with that of NMGZL patients. On multivariable analyses, performance status and stage were highly prognostic for survival for all patients. Additionally, patients treated with ABVD+/-R had markedly inferior 2-year PFS (22% versus 52%, P = 0.03) compared with DLBCL-directed therapy (CHOP+/-R and DA-EPOCH-R), which persisted on Cox regression (hazard ratio, 1.88; 95% confidence interval, 1.03-3.83; P = 0.04). Furthermore, rituximab was associated with improved PFS on multivariable analyses (hazard ratio, 0.35; 95% confidence interval, 0.18-0.69; P = 0.002). Collectively, GZL is a heterogeneous and likely more common entity and often with nonmediastinal presentation, whereas outcomes seem superior when treated with a rituximab-based, DLBCL-specific regimen.

Outcomes of Nonmyeloablative HLA-Haploidentical Blood or Marrow Transplantation With High-Dose Post-Transplantation Cyclophosphamide in Older Adults

PURPOSE

Recent advances in nonmyeloablative (NMA), related HLA-haploidentical blood or marrow transplantation (haplo-BMT) have expanded the donor pool. This study evaluated the effect of age on NMA haplo-BMT outcomes in patients age 50 to 75 years.

PATIENTS AND METHODS

A retrospective analysis was performed of 271 consecutive patients with hematologic malignancies, age 50 to 75 years, who received NMA, T-cell-replete haplo-BMT with high-dose post-transplantation cyclophosphamide.

RESULTS

The median age was 61 years, with 115 patients (42%) age 50 to 59, 129 (48%) age 60 to 69, and 27 (10%) age 70 to 75 years. Overall, 84% of patients had intermediate- or high-/very high-risk disease. The 6-month probabilities of grade 3 or 4 acute graft-versus-host disease (GVHD) and nonrelapse mortality (NRM) were 3% and 8%, respectively. Patients in their 50s, 60s, and 70s had 6-month NRM probabilities of 8%, 9%, and 7%, respectively (P=.20). With a median follow-up of 4 years, corresponding 3-year progression-free survival probabilities were 39%, 35%, and 33% (P=.65), and corresponding 3-year overall survival probabilities were 48%, 45%, and 44% (P=.66). Three-year progression-free survival probabilities were 40% in acute myeloid leukemia (n=65), 39% in aggressive non-Hodgkin lymphoma (n=83), and 37% in indolent or mantle-cell lymphoma (n=65). Older patient age was associated with a significantly higher risk of grade 2 to 4 acute GVHD but not grade 3 to 4 acute or chronic GVHD. No statistically significant associations were found between older age (relative to age 50 to 59 years or as a continuous variable) and NRM, relapse, or survival.

CONCLUSION

NMA haplo-BMT with post-transplantation cyclophosphamide has encouraging safety and survival outcomes in patients age 50 to 75 years. In patients otherwise fit for BMT, the results support consideration of this approach despite advanced age.

Phase II Study of Nonmyeloablative Allogeneic Bone Marrow Transplantation for B Cell Lymphoma with Post-Transplantation Rituximab and Donor Selection Based First on Non-HLA Factors

Outcomes of nonmyeloablative (NMA), HLA-haploidentical (haplo), related-donor allogeneic blood or marrow transplantation (allo-BMT) with high-dose post-transplantation cyclophosphamide (PTCy) appear to be similar to those using HLA-matched donors. Thus, it may be possible to prioritize donor factors other than HLA matching that could enhance antitumor activity. The Fc receptor polymorphism FCGR3A-158VV may confer greater sensitivity to rituximab than FCGR3A-158FF. In a prospective phase II study of NMA, related-donor allo-BMT with PTCy and post-transplantation rituximab for patients with B cell lymphomas, we hypothesized that donor selection that prioritized FCGR3A-158 polymorphism over HLA matching would be feasible, safe, and improve outcomes. The primary endpoint was 1-year progression-free survival (PFS). Of 83 patients transplanted (median age, 59 years), 69 (83%) received haplo grafts. Fifty-four (65%) received a graft that maintained or improved their Fc receptor polymorphism status. With 2.6-year median follow-up, the 1-year PFS and overall survival (OS) probabilities were 71% and 86%, respectively, with 1-year relapse and nonrelapse mortality (NRM) probabilities of 20% and 8%. At 1 year, the probability of acute grades II to IV graft-versus-host disease (GVHD) was 41%, with acute grades III to IV GVHD probability of 5% and chronic GVHD probability of 11%. Among haplo transplants, the 1-year probabilities of PFS, OS, relapse, and NRM were 70%, 83%, 20%, and 10%, respectively. No differences in outcomes were observed based on donor FCGR3A-158 polymorphism. Excess infection risk was not apparent with post-transplantation rituximab. Although donor selection based on FCGR3A-158 polymorphism was not shown to influence PFS, this study suggests that donor selection based on criteria other than best HLA match is feasible and safe. This study opens the way for the future investigation of donor prioritization based on promising non-HLA factors that may improve antitumor activity and decrease relapse after allo-BMT. This study was registered at www.clinicaltrials.gov as NCT00946023.

Single-agent GVHD prophylaxis with posttransplantation cyclophosphamide after myeloablative, HLA-matched BMT for AML, ALL, and MDS

High-dose, posttransplantation cyclophosphamide (PTCy) reduces severe graft-versus-host disease (GVHD) after allogeneic blood or marrow transplantation (alloBMT), but the impact of PTCy on long-term, disease-specific outcomes is unclear. We conducted a retrospective study of 209 consecutive adult patients transplanted for acute myeloid leukemia (AML, n = 138), myelodysplastic syndrome (n = 28), or acute lymphoblastic leukemia (ALL, n = 43) using PTCy as sole GVHD prophylaxis after myeloablative conditioning and HLA-matched-related or -unrelated T-cell-replete allografting. At alloBMT, 30% of patients were not in morphologic complete remission. The cumulative incidences of grades II to IV and III to IV acute GVHD at 100 days and chronic GVHD at 2 years were 45%, 11%, and 13%, respectively. Forty-three percent of patients did not require immunosuppression for any reason beyond PTCy. At 3 years, relapse cumulative incidence was 36%, disease-free survival was 46%, survival free of disease and chronic GVHD was 39%, and overall survival was 58%. Lack of remission at alloBMT, adverse cytogenetics, and low allograft nucleated cell dose were associated with inferior survival for AML patients. Minimal residual disease but not t(9;22) was associated with inferior outcomes for ALL patients. The ability to limit posttransplantation immunosuppression makes PTCy a promising transplantation platform for the integration of postgrafting strategies to prevent relapse.

Absence of post-transplantation lymphoproliferative disorder after allogeneic blood or marrow transplantation using post-transplantation cyclophosphamide as graft-versus-host disease prophylaxis

Immunosuppressive regimens that effectively prevent graft-versus-host disease (GVHD) after allogeneic blood or marrow transplantation (allo-BMT) have been associated with an increased incidence of post-transplantation lymphoproliferative disorder (PTLD) in the first year after transplantation. We evaluated the incidence of PTLD associated with the use of high-dose post-transplantation cyclophosphamide (PTCy) as GVHD prophylaxis. Between 2000 and 2011, a total of 785 adult allo-BMT recipients were given PTCy as GVHD prophylaxis at the Johns Hopkins Hospital, including 313 patients who received PTCy as sole GVHD prophylaxis. HLA-haploidentical or unrelated donor graft transplantation was performed in 526 patients (67%). No cases of PTLD occurred during the first year after allo-BMT in this series. PTLD is a rare occurrence after allo-BMT using PTCy, even in high-risk alternative donor transplantations.