A randomized phase 2 trial of pomalidomide in subjects failing prior therapy for chronic graft-versus-host disease.

Steroid-refractory chronic graft-versus-host disease (cGVHD) is a therapeutic challenge. Sclerotic skin manifestations are especially difficult to treat. We conducted a randomized phase 2 clinical trial (#NCT01688466) to determine the safety, efficacy, and preferred dose of pomalidomide in persons with moderate to severe cGVHD unresponsive to corticosteroids and/or subsequent lines of therapy. Thirty-four subjects were randomized to receive pomalidomide 0.5 mg per day orally (n = 17; low-dose cohort) or 2 mg per day at a starting dose of 0.5 mg per day increasing to 2 mg per day over 6 weeks (n = 17; high-dose cohort). The primary endpoint was overall response rate (ORR) at 6 months according to the 2005 National Institutes of Health cGVHD Response Criteria. Thirty-two patients had severe sclerotic skin and received a median of 5 (range, 2-10) previous systemic therapies. ORR was 47% (95% confidence interval, 30-65) in the intention-to-treat analyses. All were partial responses, with no difference in ORR between the cohorts. ORR was 67% (45%-84%) in the 24 evaluable subjects at 6 months. Nine had improvement in National Institutes of Health joint/fascia scores (P = .018). Median change from the baseline in body surface area involvement of skin cGVHD was -7.5% (-10% to 35%; P = .002). The most frequent adverse events were lymphopenia, infection, and fatigue. Eight subjects in the high-dose cohort had dose decreases because of adverse events. There was 1 death in the low-dose cohort from bacterial pneumonia. Our data indicate antifibrotic effects of pomalidomide and possible association with increases in concentrations of blood regulatory T-cell and interleukin-2. Pomalidomide 0.5 mg per day is a safe and effective therapy for advanced corticosteroid-refractory cGVHD.

Collection of peripheral blood mononucleated cells for chronic graft-versus-host disease immunology research: safety and effectiveness of leukapheresis in 132 patients.

BACKGROUND: Chronic graft-versus-host disease (GVHD) is a major cause of late morbidity and non-relapse mortality in recipients of allogeneic hematopoietic cell transplantation (HCT). Its biology, however, remains poorly understood, making the studies of its biology and immunomodulatory therapies a difficult task. Such research is often hampered by lymphopenia which is common in these patients and precludes studies of critical cellular subsets across the spectrum of severity of disease. This study explores the potential of leukapheresis to safely acquire and efficiently store immune cells for immunology research in chronic GVHD. METHODS: This is a cross-sectional study in which 132 consecutively accrued patients undergo optional research leukapheresis and a one-week comprehensive outpatient evaluation. Baseline clinical and laboratory data and efficiency of the procedure were reported. RESULTS: Ninety-four of 132 patients (71%) achieved the goal collection of 2 × 10^9 PBMNCs with a mean volume processed of 4.6 L. Only mild decreases in hemoglobin, platelet, lymphocyte and monocytes were observed. All adverse events were mild (grade 1) and had resolved by the time of discharge from the apheresis unit. CONCLUSION: This study demonstrates feasibility, safety, and efficiency of research leukapheresis in a frail patient population. Results presented promote leukapheresis as a standard research practice option in studies of chronic GVHD in humans which may expedite advances in our understanding of this complex multisystem disease.

Long-term follow-up after lymphodepleting autologous haematopoietic cell transplantation for treatment-resistant systemic lupus erythematosus.

OBJECTIVE: Autologous haematopoietic cell transplantation (AHSCT) improves immunologic dysfunction in patients with SLE. However, the curative potential of this therapy remains uncertain. This study reports outcomes in SLE patients receiving a lymphodepleting, reduced intensity regimen for AHSCT in SLE. METHODS: Eight patients with SLE refractory to treatment, including i.v. cyclophosphamide (CYC), were enrolled. Five had LN and three CNS involvement as primary indications for transplant. Haematopoietic cell mobilization with CYC, G-CSF and rituximab was followed by collection of CD34+ positively selected cells. The conditioning regimen consisted of concurrent administration of CYC, fludarabine and rituximab. All immunosuppressive medications were discontinued at the start of mobilization and CS were rapidly tapered after the transplant. RESULTS: Five of eight patients achieved a complete response, including a decline in the SLEDAI to zero, which was sustained in four patients for a median of 165 months (range 138-191). One patient achieved a partial response, which was followed by relapse at month 18. Two patients with nephritis and underlying comorbidities in most organs had early deaths from infection and multiorgan failure. AHSCT resulted in profound lymphodepletion, followed by expansion of Treg cells and repopulation of naive T and B cells. Patients with a complete response showed a sustained suppression of the SLE-associated IFN-induced gene signature, marked depletion of memory and plasmablast B cells and resultant sustained elimination of anti-dsDNA antibody. CONCLUSION: Durable clinical and serologic remissions with suppression in the IFN gene signature can be achieved in refractory SLE following lymphodepleting AHSCT. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov, NCT00076752.

Clinical characteristics and cytokine biomarkers in patients with chronic graft-vs-host disease persisting seven or more years after diagnosis.

Chronic graft-versus-host disease (cGVHD) is the leading late complication after allogeneic hematopoietic stem cell transplantation (HSCT). Many patients receive multiple lines of systemic therapy until cGVHD resolves, but about 15% remain on systemic treatment for more than 7 years after cGVHD diagnosis. This study describes the clinical and biological factors of patients who present with cGVHD persisting for ≥7 years (persistent cGVHD). Patients with persistent cGVHD (n = 38) and those with cGVHD for <1 year (early cGVHD) (n = 83) were enrolled in a prospective cross-sectional natural history study. Patients in the persistent cGVHD group were a median of 10.2 years from cGVHD diagnosis (range 7-27 years). Fifty-eight percent of persistent cGVHD patients (22/38) were receiving systemic immunosuppression, compared to 88% (73/83) in the early cGVHD group. In multivariable analysis, bone marrow (BM) stem cell source, presence of ENA autoantibodies, higher NIH lung score, higher platelet counts, and higher IgA levels were significantly associated with persistent cGVHD. A high sensitivity panel of serum biomarkers including seven cytokines diagnostic for cGVHD was analyzed and showed significantly lower levels of BAFF and CXCL10 in patients with persistent cGVHD. In conclusion, standardly accepted clinical measures of disease severity may not accurately reflect disease activity in patients with persistent cGVHD. However, many patients with persistent cGVHD are still receiving systemic immunosuppression despite lacking evidence of disease activity. Development of reliable clinical biomarkers of cGVHD activity may help guide future systemic treatments.

An aberrant NOTCH2-BCR signaling axis in B cells from patients with chronic GVHD.

B-cell receptor (BCR)-activated B cells contribute to pathogenesis in chronic graft-versus-host disease (cGVHD), a condition manifested by both B-cell autoreactivity and immune deficiency. We hypothesized that constitutive BCR activation precluded functional B-cell maturation in cGVHD. To address this, we examined BCR-NOTCH2 synergy because NOTCH has been shown to increase BCR responsiveness in normal mouse B cells. We conducted ex vivo activation and signaling assays of 30 primary samples from hematopoietic stem cell transplantation patients with and without cGVHD. Consistent with a molecular link between pathways, we found that BCR-NOTCH activation significantly increased the proximal BCR adapter protein BLNK. BCR-NOTCH activation also enabled persistent NOTCH2 surface expression, suggesting a positive feedback loop. Specific NOTCH2 blockade eliminated NOTCH-BCR activation and significantly altered NOTCH downstream targets and B-cell maturation/effector molecules. Examination of the molecular underpinnings of this "NOTCH2-BCR axis" in cGVHD revealed imbalanced expression of the transcription factors IRF4 and IRF8, each critical to B-cell differentiation and fate. All-trans retinoic acid (ATRA) increased IRF4 expression, restored the IRF4-to-IRF8 ratio, abrogated BCR-NOTCH hyperactivation, and reduced NOTCH2 expression in cGVHD B cells without compromising viability. ATRA-treated cGVHD B cells had elevated TLR9 and PAX5, but not BLIMP1 (a gene-expression pattern associated with mature follicular B cells) and also attained increased cytosine guanine dinucleotide responsiveness. Together, we reveal a mechanistic link between NOTCH2 activation and robust BCR responses to otherwise suboptimal amounts of surrogate antigen. Our findings suggest that peripheral B cells in cGVHD patients can be pharmacologically directed from hyperactivation toward maturity.

T cells expressing an anti-B-cell maturation antigen chimeric antigen receptor cause remissions of multiple myeloma.

Therapies with novel mechanisms of action are needed for multiple myeloma (MM). B-cell maturation antigen (BCMA) is expressed in most cases of MM. We conducted the first-in-humans clinical trial of chimeric antigen receptor (CAR) T cells targeting BCMA. T cells expressing the CAR used in this work (CAR-BCMA) specifically recognized BCMA-expressing cells. Twelve patients received CAR-BCMA T cells in this dose-escalation trial. Among the 6 patients treated on the lowest 2 dose levels, limited antimyeloma activity and mild toxicity occurred. On the third dose level, 1 patient obtained a very good partial remission. Two patients were treated on the fourth dose level of 9 × 10(6) CAR(+) T cells/kg body weight. Before treatment, the first patient on the fourth dose level had chemotherapy-resistant MM, making up 90% of bone marrow cells. After treatment, bone marrow plasma cells became undetectable by flow cytometry, and the patient's MM entered a stringent complete remission that lasted for 17 weeks before relapse. The second patient on the fourth dose level had chemotherapy-resistant MM making up 80% of bone marrow cells before treatment. Twenty-eight weeks after this patient received CAR-BCMA T cells, bone marrow plasma cells were undetectable by flow cytometry, and the serum monoclonal protein had decreased by >95%. This patient is in an ongoing very good partial remission. Both patients treated on the fourth dose level had toxicity consistent with cytokine-release syndrome including fever, hypotension, and dyspnea. Both patients had prolonged cytopenias. Our findings demonstrate antimyeloma activity of CAR-BCMA T cells. This trial was registered to www.clinicaltrials.gov as #NCT02215967.

Upregulation of IFN-Inducible and Damage-Response Pathways in Chronic Graft-versus-Host Disease.

Although chronic graft-versus-host disease (CGVHD) is the primary nonrelapse complication of allogeneic transplantation, understanding of its pathogenesis is limited. To identify the main operant pathways across the spectrum of CGVHD, we analyzed gene expression in circulating monocytes, chosen as in situ systemic reporter cells. Microarrays identified two interrelated pathways: 1) IFN-inducible genes, and 2) innate receptors for cellular damage. Corroborating these with multiplex RNA quantitation, we found that multiple IFN-inducible genes (affecting lymphocyte trafficking, differentiation, and Ag presentation) were concurrently upregulated in CGVHD monocytes compared with normal subjects and non-CGVHD control patients. IFN-inducible chemokines were elevated in both lichenoid and sclerotic CGHVD plasma and were linked to CXCR3+ lymphocyte trafficking. Furthermore, the levels of the IFN-inducible genes CXCL10 and TNFSF13B (BAFF) were correlated at both the gene and the plasma levels, implicating IFN induction as a factor in elevated BAFF levels in CGVHD. In the second pathway, damage-/pathogen-associated molecular pattern receptor genes capable of inducing type I IFN were upregulated. Type I IFN-inducible MxA was expressed in proportion to CGVHD activity in skin, mucosa, and glands, and expression of TLR7 and DDX58 receptor genes correlated with upregulation of type I IFN-inducible genes in monocytes. Finally, in serial analyses after transplant, IFN-inducible and damage-response genes were upregulated in monocytes at CGVHD onset and declined upon therapy and resolution in both lichenoid and sclerotic CGVHD patients. This interlocking analysis of IFN-inducible genes, plasma analytes, and tissue immunohistochemistry strongly supports a unifying hypothesis of induction of IFN by innate response to cellular damage as a mechanism for initiation and persistence of CGVHD.

The Biology of Chronic Graft-versus-Host Disease: A Task Force Report from the National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease.

Chronic graft-versus-host disease (GVHD) is the leading cause of late, nonrelapse mortality and disability in allogeneic hematopoietic cell transplantation recipients and a major obstacle to improving outcomes. The biology of chronic GVHD remains enigmatic, but understanding the underpinnings of the immunologic mechanisms responsible for the initiation and progression of disease is fundamental to developing effective prevention and treatment strategies. The goals of this task force review are as follows: This document is intended as a review of our understanding of chronic GVHD biology and therapies resulting from preclinical studies, and as a platform for developing innovative clinical strategies to prevent and treat chronic GVHD.

Serial changes in lymphocyte subsets in patients with newly diagnosed high grade astrocytomas treated with standard radiation and temozolomide.

The immune system plays a significant role in cancer prevention and outcome. In high grade astrocytomas (HGA), severe lymphopenia is associated with shortened survival due to tumor progression. This study was performed to quantify serial changes in lymphocyte subsets in HGA following standard radiation (RT) and temozolomide (TMZ). Adults (KPS >60, HIV negative) with newly diagnosed HGA scheduled to receive concurrent RT and TMZ and adjuvant TMZ were eligible. Blood was collected before beginning concurrent RT/TMZ and at weeks 6, 10, 18, and 26, and 3 months after completing adjuvant TMZ. Lymphocyte subsets were analyzed by flow cytometry. Twenty patients (70% glioblastoma, median age 53, 50% male, 80% Caucasian) who enrolled from January 2014 to August 2014 were followed until April 2016. Baseline dexamethasone dose was 0.5 mg/day and 15% had absolute lymphocyte counts (ALC) <1000 cells/mm3 before starting RT/TMZ. However, 75% developed lymphopenia with ALC <1000 cells/mm3 after completion of RT/TMZ. NK cells, B cells and all T lymphocytes subsets dropped significantly after concurrent RT/TMZ and remained depressed for the 48 weeks of observation. The CD4+/CD8+ ratio was not affected significantly during follow-up. Severe lymphopenia involving all subsets occurred early in treatment and remained present for nearly 1 year. To our knowledge, this is the first report of serial trends in lymphocyte subsets following standard RT and TMZ for HGA.

Bone marrow-derived mesenchymal stromal cells harness purinergenic signaling to tolerize human Th1 cells in vivo.

The use of bone marrow-derived mesenchymal stromal cells (BMSC) in the treatment of alloimmune and autoimmune conditions has generated much interest, yet an understanding of the therapeutic mechanism remains elusive. We therefore explored immune modulation by a clinical-grade BMSC product in a model of human-into-mouse xenogeneic graft-versus-host disease (x-GVHD) mediated by human CD4(+) Th1 cells. BMSC reversed established, lethal x-GVHD through marked inhibition of Th1 cell effector function. Gene marking studies indicated BMSC engraftment was limited to the lung; furthermore, there was no increase in regulatory T cells, thereby suggesting a paracrine mechanism of BMSC action. BMSC recipients had increased serum CD73 expressing exosomes that promoted adenosine accumulation ex vivo. Importantly, immune modulation mediated by BMSC was fully abrogated by pharmacologic therapy with an adenosine A2A receptor antagonist. To investigate the potential clinical relevance of these mechanistic findings, patient serum samples collected pre- and post-BMSC treatment were studied for exosome content: CD73 expressing exosomes promoting adenosine accumulation were detected in post-BMSC samples. In conclusion, BMSC effectively modulate experimental GVHD through a paracrine mechanism that promotes adenosine-based immune suppression.

National Institutes of Health Consensus Development Project on Criteria for Clinical Trials in Chronic Graft-versus-Host Disease: III. The 2014 Biomarker Working Group Report.

Biology-based markers to confirm or aid in the diagnosis or prognosis of chronic graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation or monitor its progression are critically needed to facilitate evaluation of new therapies. Biomarkers have been defined as any characteristic that is objectively measured and evaluated as an indicator of a normal biological or pathogenic process, or of a pharmacologic response to a therapeutic intervention. Applications of biomarkers in chronic GVHD clinical trials or patient management include the following: (1) diagnosis and assessment of chronic GVHD disease activity, including distinguishing irreversible damage from continued disease activity; (2) prognostic risk to develop chronic GVHD; and (3) prediction of response to therapy. Sample collection for chronic GVHD biomarkers studies should be well documented following established quality control guidelines for sample acquisition, processing, preservation, and testing, at intervals that are both calendar and event driven. The consistent therapeutic treatment of subjects and standardized documentation needed to support biomarker studies are most likely to be provided in prospective clinical trials. To date, no chronic GVHD biomarkers have been qualified for use in clinical applications. Since our previous chronic GVHD Biomarkers Working Group report in 2005, an increasing number of chronic GVHD candidate biomarkers are available for further investigation. This paper provides a 4-part framework for biomarker investigations: identification, verification, qualification, and application with terminology based on Food and Drug Administration and European Medicines Agency guidelines.

Phase 2 clinical trial of rapamycin-resistant donor CD4+ Th2/Th1 (T-Rapa) cells after low-intensity allogeneic hematopoietic cell transplantation.

In experimental models, ex vivo induced T-cell rapamycin resistance occurred independent of T helper 1 (Th1)/T helper 2 (Th2) differentiation and yielded allogeneic CD4(+) T cells of increased in vivo efficacy that facilitated engraftment and permitted graft-versus-tumor effects while minimizing graft-versus-host disease (GVHD). To translate these findings, we performed a phase 2 multicenter clinical trial of rapamycin-resistant donor CD4(+) Th2/Th1 (T-Rapa) cells after allogeneic-matched sibling donor hematopoietic cell transplantation (HCT) for therapy of refractory hematologic malignancy. T-Rapa cell products, which expressed a balanced Th2/Th1 phenotype, were administered as a preemptive donor lymphocyte infusion at day 14 post-HCT. After T-Rapa cell infusion, mixed donor/host chimerism rapidly converted, and there was preferential immune reconstitution with donor CD4(+) Th2 and Th1 cells relative to regulatory T cells and CD8(+) T cells. The cumulative incidence probability of acute GVHD was 20% and 40% at days 100 and 180 post-HCT, respectively. There was no transplant-related mortality. Eighteen of 40 patients (45%) remain in sustained complete remission (range of follow-up: 42-84 months). These results demonstrate the safety of this low-intensity transplant approach and the feasibility of subsequent randomized studies to compare T-Rapa cell-based therapy with standard transplantation regimens.

Donor-derived CD19-targeted T cells cause regression of malignancy persisting after allogeneic hematopoietic stem cell transplantation.

New treatments are needed for B-cell malignancies persisting after allogeneic hematopoietic stem cell transplantation (alloHSCT). We conducted a clinical trial of allogeneic T cells genetically modified to express a chimeric antigen receptor (CAR) targeting the B-cell antigen CD19. T cells for genetic modification were obtained from each patient's alloHSCT donor. All patients had malignancy that persisted after alloHSCT and standard donor lymphocyte infusions (DLIs). Patients did not receive chemotherapy prior to the CAR T-cell infusions and were not lymphocyte depleted at the time of the infusions. The 10 treated patients received a single infusion of allogeneic anti-CD19-CAR T cells. Three patients had regressions of their malignancies. One patient with chronic lymphocytic leukemia (CLL) obtained an ongoing complete remission after treatment with allogeneic anti-CD19-CAR T cells, another CLL patient had tumor lysis syndrome as his leukemia dramatically regressed, and a patient with mantle cell lymphoma obtained an ongoing partial remission. None of the 10 patients developed graft-versus-host disease (GVHD). Toxicities included transient hypotension and fever. We detected cells containing the anti-CD19-CAR gene in the blood of 8 of 10 patients. These results show for the first time that donor-derived allogeneic anti-CD19-CAR T cells can cause regression of B-cell malignancies resistant to standard DLIs without causing GVHD.

Costimulated tumor-infiltrating lymphocytes are a feasible and safe alternative donor cell therapy for relapse after allogeneic stem cell transplantation.

Donor lymphocyte infusion (DLI), a standard relapse treatment after allogeneic stem cell transplantation (AlloSCT), has limited efficacy and often triggers GVHD. We hypothesized that after AlloSCT tumor-infiltrating donor lymphocytes could be costimulated ex vivo to preferentially activate/expand antitumor effectors. We tested the feasibility and safety of costimulated, tumor-derived donor lymphocyte (TDL) infusion in a phase 1 trial. Tumor was resected from 8 patients with B-cell malignancy progression post-AlloSCT; tumor cell suspensions were costimulated with anti-CD3/anti-CD28 Ab-coated magnetic beads and cultured to generate TDL products for each patient. Costimulation yielded increased proportions of T-bet(+)FoxP3(-) type 1 effector donor T cells. A median of 2.04 × 10(7) TDL/kg was infused; TDLs were well tolerated, notably without GVHD. Two transient positron emission tomography (PET) responses and 2 mixed responses were observed in these refractory tumors. TDL are a feasible, tolerable, and novel donor cell therapy alternative for relapse after AlloSCT.

Heightened TLR7 signaling primes BCR-activated B cells in chronic graft-versus-host disease for effector functions.

ABSTRACT: Chronic graft-versus-host disease (cGVHD) is a debilitating, autoimmune-like syndrome that can occur after allogeneic hematopoietic stem cell transplantation. Constitutively activated B cells contribute to ongoing alloreactivity and autoreactivity in patients with cGVHD. Excessive tissue damage that occurs after transplantation exposes B cells to nucleic acids in the extracellular environment. Recognition of endogenous nucleic acids within B cells can promote pathogenic B-cell activation. Therefore, we hypothesized that cGVHD B cells aberrantly signal through RNA and DNA sensors such as Toll-like receptor 7 (TLR7) and TLR9. We found that B cells from patients and mice with cGVHD had higher expression of TLR7 than non-cGVHD B cells. Using ex vivo assays, we found that B cells from patients with cGVHD also demonstrated increased interleukin-6 production after TLR7 stimulation with R848. Low-dose B-cell receptor (BCR) stimulation augmented B-cell responses to TLR7 activation. TLR7 hyperresponsiveness in cGVHD B cells correlated with increased expression and activation of the downstream transcription factor interferon regulatory factor 5. Because RNA-containing immune complexes can activate B cells through TLR7, we used a protein microarray to identify RNA-containing antigen targets of potential pathological relevance in cGVHD. We found that many of the unique targets of active cGVHD immunoglobulin G (IgG) were nucleic acid-binding proteins. This unbiased assay identified the autoantigen and known cGVHD target Ro-52, and we found that RNA was required for IgG binding to Ro-52. Herein, we find that BCR-activated B cells have aberrant TLR7 signaling responses that promote potential effector responses in cGVHD.

High-dose Alemtuzumab-Cyclosporine vs Tacrolimus-Methotrexate-Sirolimus for Chronic Graft-versus-Host Disease Prevention.

Chronic graft-versus-host disease (cGVHD) remains a significant problem for patients after allogeneic hematopoietic stem cell transplants (allo-HSCT). While in vivo lymphodepletion by antibodies for cGVHD prophylaxis has been explored in the myeloablative setting, its effects after reduced intensity conditioning (RIC) are not well described. Patients (n=83) with hematologic malignancies underwent targeted lymphodepletion chemotherapy followed by a RIC allo-HSCT using peripheral blood stem cells from unrelated donors. Patients were randomized to two GVHD prophylaxis arms: high-dose alemtuzumab/cyclosporine (AC, n=44) and tacrolimus/methotrexate/sirolimus (TMS, n=39) with the primary endpoint of cumulative incidence of severe cGVHD. The incidence of severe cGVHD was lower with AC vs TMS prophylaxis at 1- and 5-years (0% vs 10.3% and 4.5% vs 28.5%, overall p=0.0002), as well as any grade (p=0.003) and moderate-severe (p<0.0001) cGVHD. AC was associated with higher rates of grade III-IV infections (p=0.02) and relapse (52% vs 21%, p=0.003) with a shorter 5-year PFS (18% vs 41%, p=0.01) and no difference in 5-year GRFS, OS, or NRM. AC severely depleted naïve T-cells reconstitution, resulting in reduced TCR repertoire diversity, smaller populations of CD4 Treg and CD8 Tscm, but a higher ratio of Treg to naïve T-cells at 6 months. In summary, an alemtuzumab-based regimen successfully reduced the rate and severity of cGVHD after RIC allo-HSCT and resulted in a distinct immunomodulatory profile which may have reduced cGVHD incidence and severity. However, increased infections and relapse resulted in a lack of survival benefit after long-term follow-up. ClinicalTrials.gov identifier: NCT00520130.

Host lymphocyte depletion as a strategy to facilitate early full donor chimerism after reduced-intensity allogeneic stem cell transplantation.

Reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (RIC-alloHSCT) is associated with lower toxicity but higher rates of prolonged mixed chimerism than myeloablative conditioning. Decreased pretransplantation host T cell numbers are associated with less graft rejection and early full donor chimerism. To compensate for variability in pretransplantation host lymphocyte numbers and facilitate the achievement of rapid full donor chimerism, we tested a strategy of targeted lymphocyte depletion (TLD) using chemotherapy at conventional doses to provide cytoreduction and lymphocyte depletion before RIC-alloHSCT. In our study, 111 patients with advanced hematologic malignancies received 1 to 3 cycles of conventional-dose chemotherapy to reduce circulating lymphocytes to a predetermined level. Patients then underwent RIC-alloHSCT from HLA-matched siblings. Patients received a median of 2 cycles of TLD chemotherapy, resulting in a median 71% decline in CD4(+) count. All patients engrafted; there were no late graft failures. By day +14, median CD3(+) chimerism was 99% donor and was significantly associated with lower post-TLD CD4(+) counts (P = .012). One- and 5-year treatment-related mortality were 15% and 21%, respectively. At 1-year follow-up, 66% of patients had achieved complete remission (CR) of which 92% were not in CR at the time of transplantation. Overall survival at 1 and 5 years post transplantation were 66% and 47%, respectively.

Evolution of the donor T-cell repertoire in recipients in the second decade after allogeneic stem cell transplantation.

After allogeneic stem cell transplantation (SCT), T lymphocyte function is reestablished from the donor's postthymic T cells and through thymic T-cell neogenesis. The immune repertoire and its relation to that of the donor have not been characterized in detail in long-term adult SCT survivors. We studied 21 healthy patients in their second decade after a myeloablative SCT for hematologic malignancy (median follow-up, 12 years). Immune profiles were compared with donor samples cryopreserved at transplant and beyond 10 years from SCT. Only one recipient was on continuing immunosuppression. Compared with the donor at transplant, there was no significant difference in CD4, CD8, natural killer, and B-cell blood counts. However, compared with donors, recipients had significantly fewer naive T cells, lower T-cell receptor excision circle levels, fewer CD4 central memory cells, more effector CD8(+) cells, and more regulatory T cells. TCR repertoire analysis showed no significant difference in complexity of TCRVß spectratype between recipients and donors, although spectratype profiles had diverged with both gain and loss of donor repertoire peaks in the recipient. In conclusion, long-term allogeneic SCT survivors have subtle defects in their immune profile consistent with defective thymic function but compatible with normal health. This study is registered at http://www.clinicaltrials.gov as NCT00106925.

Single-cell landscape analysis unravels molecular programming of the human B cell compartment in chronic GVHD.

Alloreactivity can drive autoimmune syndromes. After allogeneic hematopoietic stem cell transplantation (allo-HCT), chronic graft-versus-host disease (cGVHD), a B cell-associated autoimmune-like syndrome, commonly occurs. Because donor-derived B cells continually develop under selective pressure from host alloantigens, aberrant B cell receptor (BCR) activation and IgG production can emerge and contribute to cGVHD pathobiology. To better understand molecular programing of B cells in allo-HCT, we performed scRNA-Seq analysis on high numbers of purified B cells from patients. An unsupervised analysis revealed 10 clusters, distinguishable by signature genes for maturation, activation, and memory. Within the memory B cell compartment, we found striking transcriptional differences in allo-HCT patients compared with healthy or infected individuals, including potentially pathogenic atypical B cells (ABCs) that were expanded in active cGVHD. To identify intrinsic alterations in potentially pathological B cells, we interrogated all clusters for differentially expressed genes (DEGs) in active cGVHD versus patients who never had signs of immune tolerance loss (no cGVHD). Active cGVHD DEGs occurred in both naive and BCR-activated B cell clusters. Remarkably, some DEGs occurred across most clusters, suggesting common molecular programs that may promote B cell plasticity. Our study of human allo-HCT and cGVHD provides understanding of altered B cell memory during chronic alloantigen stimulation.

Salivary ZG16B expression loss follows exocrine gland dysfunction related to oral chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) targets include the oral mucosa and salivary glands after allogeneic hematopoietic stem cell transplant (HSCT). Without incisional biopsy, no diagnostic test exists to confirm oral cGVHD. Consequently, therapy is often withheld until severe manifestations develop. This proteomic study examined saliva and human salivary gland for a biomarker profile at first onset of oral cGVHD prior to initiation of topical steroid therapy. Whole saliva collected at onset of biopsy-proven oral GVHD was assessed using liquid chromatography-coupled tandem mass spectrometry with identification of 569 proteins, of which 77 significantly changed in abundance. ZG16B, a secretory lectin protein, was reduced 2-fold in oral cGVHD saliva (p <0.05), and significantly decreased in salivary gland secretory cells affected by cGVHD. Single-cell RNA-seq analysis of healthy MSG localized ZG16B expression to two discrete acinar cell populations. Reduced ZG16B expression may indicate specific cGVHD activity and possibly general salivary gland dysfunction.