Myeloablative versus reduced intensity allogeneic stem cell transplantation for relapsed/refractory Hodgkin's lymphoma in recent years: a retrospective analysis of the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation.

BACKGROUND: To evaluate long-term outcome of myeloablative allogeneic stem cell transplantation (allo-SCT) (MAC) versus reduced-intensity allo-SCT (RIC) in patients with relapsed/refractory Hodgkin's lymphoma (HL) in recent years. PATIENTS AND METHODS: A total of 312 patients (63 MAC and 249 RIC) with relapsed/refractory HL who received allo-SCT between 2006 and 2010 and were reported to the EBMT Database were included in the study. RESULTS: With a median follow-up for alive patients of 56 (26-73) months, there were no significant differences in non-relapse mortality (NRM) between MAC and RIC. Relapse rate (RR) was somewhat lower in the MAC group (41% versus 52% at 24 months, P = 0.16). This lower RR translated into a marginal improvement in event-free survival (EFS) for the MAC group (48% versus 36% at 24 months, P = 0.09) with no significant differences in overall survival (73% for MAC and 62% for RIC at 24 months, P = 0.13). Multivariate analysis after adjusting for disease status at the time of allo-SCT showed that the use of MAC was of borderline statistical significance for predicting a lower RR and EFS [HR 0.7, 95% CI (0.5-1.0), P = 0.1] and [HR 0.7, 95% CI (0.5-1.0), P = 0.07], respectively, after allo-SCT. CONCLUSIONS: With modern transplant practices, the NRM associated with MAC for HL has strongly decreased, resulting into non-significant improvement of EFS because of a somewhat better disease control compared with RIC transplants. The intensity of conditioning regimens should be considered when designing individual allo-SCT strategies or clinical trials in patients with relapsed/refractory HL.

16th IHIW: international histocompatibility working group in hematopoietic cell transplantation.

The International Histocompatibility Working Group is a collaborative international effort to understand the HLA and non-HLA genetics of the transplantation barrier. The Working Group is comprised of experts in the fields of histocompatibility and immunogenetics, hematopoietic cell transplantation and outcomes research. Data for 25 855 unrelated donor transplants were submitted in support of research studies for the 16th International Histocompatibility Workshop. Active investigation is in progress in seven key areas: the impact of HLA matching, role of race and ethnicity, identification of permissible HLA mismatches, haplotype-associated determinants, minor histocompatibility antigens, immune response genes and KIR genetics. New hypotheses for the 16th workshop were developed for immunogenetic studies in cord blood and haploidentical-related donor transplantation.

HLA-haploidentical hematopoietic stem cells transplantation with regulatory and conventional T-cell adoptive immunotherapy in pediatric patients with very high-risk acute leukemia.

Allogeneic hematopoietic stem cell transplantation (HSCT) is still needed for many children with very high-risk acute leukemia. An HLA-haploidentical family donor is a suitable option for those without an HLA-matched donor. Here we present outcomes of a novel HLA-haploidentical HSCT (haplo-HSCT) strategy with adoptive immunotherapy with thymic-derived CD4+CD25+ FoxP3+ regulatory T cells (Tregs) and conventional T cells (Tcons) performed between January 2017 and July 2021 in 20 children with high-risk leukemia. Median age was 14.5 years (range, 4-21), 15 had acute lymphoblastic leukemia, 5 acute myeloid leukemia. The conditioning regimen included total body irradiation (TBI), thiotepa, fludarabine, cyclophosphamide. Grafts contained a megadose of CD34+ cells (mean 12.4 × 106/Kg), Tregs (2 × 106/Kg) and Tcons (0.5-1 × 106/Kg). All patients achieved primary, sustained full-donor engraftment. Only one patient relapsed (5%). The incidence of non-relapse mortality was 15% (3/20 patients). Five/20 patients developed ≥ grade 2 acute Graft versus Host Disease (aGvHD). It resolved in 4 who are alive and disease-free; 1 patient developed chronic GvHD (cGvHD). The probability of GRFS was 60 ± 0.5% (95% CI: 2.1-4.2) (Fig. 6), CRFS was 79 ± 0.9% (95% CI: 3.2-4.9) as 16/20 patients are alive and leukemia-free. The median follow-up was 2.1 years (range 0.5 months-5.1 years). This innovative approach was associated with very promising outcomes of HSCT strategy in pediatric patients.

Natural killer cell-mediated lysis of autologous cells modified by gene therapy.

This study investigated the role of natural killer (NK) cells as effectors of an immune response against autologous cells modified by gene therapy. T lymphocytes were transduced with LXSN, a retroviral vector adopted for human gene therapy that carries the selectable marker gene neo, and the autologous NK response was evaluated. We found that (i) infection with LXSN makes cells susceptible to autologous NK cell-mediated lysis; (ii) expression of the neo gene is responsible for conferring susceptibility to lysis; (iii) lysis of neo-expressing cells is clonally distributed and mediated only by NK clones that exhibit human histocompatibility leukocyte antigen (HLA)-Bw4 specificity and bear KIR3DL1, a Bw4-specific NK inhibitory receptor; and (iv) the targets are cells from HLA-Bw4(+) individuals. Finally, neo peptides anchoring to the Bw4 allele HLA-B27 interfered with KIR3DL1-mediated recognition of HLA-B27, i.e., they triggered NK lysis. Moreover, neo gene mutations preventing translation of two of the four potentially nonprotective peptides reduced KIR3DL1(+) NK clone-mediated autologous lysis. Thus, individuals expressing Bw4 alleles possess an NK repertoire with the potential to eliminate autologous cells modified by gene therapy. By demonstrating that NK cells can selectively detect the expression of heterologous genes, these observations provide a general model of the NK cell-mediated control of viral infections.

Is there a stronger graft-versus-leukemia effect using HLA-haploidentical donors compared with HLA-identical siblings?

Haploidentical hematopoietic stem cell transplants (HSCTs) are increasingly used, but it is unknown whether they have a stronger graft-versus-leukemia (GVL) effect. We analyzed 10 679 acute leukemia patients who underwent HSCT from an HLA-matched sibling donor (MSD, n=9815) or a haploidentical donor (⩾2 HLA-antigen disparity, n=864) between 2007 and 2012, reported to the European Group for Blood and Marrow Transplantation. In a Cox regression model, acute and chronic graft-versus-host disease (GVHD) was added as time-dependent variables. There was no difference in probability of relapse between recipients of haploidentical and MSD grafts. Factors of importance for relapse after T-cell-replete grafts included remission status at HSCT, Karnofsky score ⩽80, acute GVHD of grade II or higher and chronic GVHD (P<10(-5)). Patients with post-transplant cyclophosphamide (n=194) had similar outcome as other T-cell-replete haploidentical transplants (n=369). Non-relapse mortality was significantly higher in the haploidentical group compared with that in MSD patients (P<10(-5)). Leukemia-free survival was superior in the MSD patients receiving T-cell-replete (P<10(-5)) or T-cell-depleted grafts (P=0.0006). The risk of relapse was the same in acute leukemia patients who received haploidentical donor grafts as in those given MSD transplants, suggesting a similar GVL effect.

The in vivo effect of thymic factor (thymostimulin) administration on circulating immune complexes and serum lysozyme levels in untreated Hodgkin's disease patients.

The in vivo effect of a calf thymus extract, thymostimulin, on the levels of circulating immune complexes (CIC) and serum lysozyme was evaluated in 32 patients with untreated Hodgkin's disease. Using the platelet aggregation test for detecting CICs, 12 patients (37%) had positive titers before thymostimulin treatment; 3 patients (10%) remained positive following therapy. Serum levels of Clq-binding immune complexes were evaluated (greater than 24.5 micrograms/ml) in 8 patients prior to thymostimulin therapy (mean value: 42.3 micrograms/ml); 3 patients continued to have elevated levels after treatment. Serum lysozyme levels for Hodgkin's patients was similar to control values (10.6 vs. 8.3 micrograms/ml); however, the Hodgkin's patients with initially elevated CICs had a lower serum lysozyme level than patients with initially normal CICs (12.9 vs. 7.3, p less than 0.02). Thymostimulin increased serum lysozyme levels in the Hodgkin's patients in whom the CICs were initially elevated (7.3 vs. 10.4 micrograms/ml, p less than 0.05). These data suggest that thymostimulin exerts an effect on the nonspecific immune system of Hodgkin's disease patients.

Increased serum levels of soluble CD44 standard, but not of variant isoforms v5 and v6, in B cell chronic lymphocytic leukemia.

The CD44 cell surface proteoglycan participates in a variety of functions including lymphohematopoiesis, lymphocyte homing and tumor metastasis. In addition to the standard form (CD44st), a large family of variant isoforms (CD44v) is generated by alternative splicing of a single gene. Certain CD44v (v5 and V6) are upregulated in the course of neoplastic progression and reflect the metastatic potential of tumor cells. CD44 v6 is expressed in high-grade non-Hodgkin's lymphoma cells and is released in the serum, thus providing a soluble marker that reflects tumor burden, disease progression and treatment response. Here we show that serum CD44st is elevated in approximately half of B-CLL patients. In contrast, CD44v5 and v6 are detected at normal levels in the large majority of the cases. CD44st serum levels correlate significantly with the number of circulating leukemic B cells and with the levels of another soluble B-CLL marker, beta2-microglobulin. Immunoprecipitation analyses of B-CLL sera allow detection of several high molecular weight bands and of a 78 kDa band that represents a soluble form of CD44st and is 4 kDa lower than a similar band (82 kDa) detected in B-CLL cell lysates. Elevated serum CD44st associates with a number of unfavorable prognostic factors such as high peripheral blood lymphocytosis, splenomegaly, advanced disease stage and therapy requirement. A follow-up study indicates that serum levels of CD44st are related to disease status, thus reinforcing our veiw that this molecule may represent a reliable tumor marker in B-CLL.

Next generation HLA-haploidentical HSCT.

Relapse is still the major cause of failure of allogeneic stem cell transplantation in high-risk acute leukemia patients. Indeed, whoever the donor and whatever the transplantation strategy, post-transplant relapse rates are ~30%, which is hardly satisfactory. The present phase 2 study analyzed the impact of adoptive immunotherapy with naturally occurring FoxP3+ T-regulatory cells (2 × 10(6) per kg) and conventional T lymphocytes (1 × 10(6) per kg) on prevention of GvHD and leukemia relapse in 43 high-risk adults undergoing full-haplotype mismatched transplantation without any post-transplant immunosuppression. Ninety-five percent of patients achieved full-donor type engraftment. Only 6/41 patients (15%) developed ⩾ grade II acute GvHD. Specific CD4(+) and CD8(+) for opportunistic pathogens emerged significantly earlier than after standard T-cell-depleted haplo-transplantation. The probability of disease-free survival was 0.56. At a median follow-up of 46 months (range 18-65 months), only 2/41 evaluable patients have relapsed. The cumulative incidence of relapse was significantly lower than in historical controls (0.05 vs 0.21; P = 0.03). These results demonstrate that the immunosuppressive potential of Tregs can be used to suppress GvHD without loss of the benefits of GvL activity. Humanized murine models provided insights into the mechanisms underlying separation of GvL from GvHD.

SCT for severe autoimmune diseases: consensus guidelines of the European Society for Blood and Marrow Transplantation for immune monitoring and biobanking.

Over the past 15 years, SCT has emerged as a promising treatment option for patients with severe autoimmune diseases (ADs). Mechanistic studies recently provided the proof-of-concept that restoration of immunological tolerance can be achieved by haematopoietic SCT in chronic autoimmunity through eradication of the pathologic, immunologic memory and profound reconfiguration of the immune system, that is, immune 'resetting'. Nevertheless, a number of areas remain unresolved and warrant further investigation to refine our understanding of the underlying mechanisms of action and to optimize clinical SCT protocols. Due to the low number of patients transplanted in each centre, it is essential to adequately collect and analyse biological samples in a larger cohort of patients under standardized conditions. The European society for blood and marrow transplantation Autoimmune Diseases and Immunobiology Working Parties have, therefore, undertaken a joint initiative to develop and implement guidelines for 'good laboratory practice' in relation to procurement, processing, storage and analysis of biological specimens for immune reconstitution studies in AD patients before, during and after SCT. The aim of this document is to provide practical recommendations for biobanking of samples and laboratory immune monitoring in patients with ADs undergoing SCT, both for routine supportive care purposes and investigational studies.

Indications for allo- and auto-SCT for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2015.

This is the sixth special report that the European Society for Blood and Marrow Transplantation regularly publishes on the current practice and indications for haematopoietic SCT for haematological diseases, solid tumours and immune disorders in Europe. Major changes have occurred in the field of haematopoietic SCT over the last years. Cord blood units as well as haploidentical donors have been increasingly used as stem cell sources for allo-SCT, thus, augmenting the possibility of finding a suitable donor for a patient. Continuous refinement of conditioning strategies has also expanded not only the number of potential indications but also has permitted consideration of older patients or those with co-morbidity for a transplant. There is accumulating evidence of the role of haematopoietic SCT in non-haematological disorders such as autoimmune diseases. On the other hand, the advent of new drugs and very effective targeted therapy has challenged the role of SCT in some instances or at least, modified its position in the treatment armamentarium of a given patient. An updated report with revised tables and operating definitions is presented.

Haploidentical stem cell transplantation in leukemia.

In acute leukemia patients, infusing a megadose of extensively T-cell-depleted hematopoietic stem cells after an immuno-myeloablative conditioning regimen ensures sustained engraftment of full-haplotype mismatched transplants without graft-vs-host disease. Besides the conditioning regimen and the megadose of stem cells donor natural killer cell alloreactivity also plays a role in facilitating engraftment and in preventing relapse. Since our first successful pilot study, our efforts have concentrated on developing new conditioning regimens, optimizing the graft processing and improving the post-transplant immunological recovery. The results we have so far achieved in 112 very high-risk acute leukemia patients show that haploidentical transplantation is now a clinical reality. Because virtually all patients in need of a hematopoietic stem cell transplant have a full-haplotype mismatched donor, who is immediately available, a T-cell depleted mismatched transplant should be offered, not as a last resort, but as a viable option to high risk acute leukemia patients who do not have, or cannot find, a matched donor.

Right ventricular myocardial protection through intracavitary cooling in cardiac operations.

In an attempt to protect the right ventricle, we designed and tested a closed cooling system that circulates cold saline through a double-lumen, balloon-tipped catheter positioned in the right ventricular cavity. Fourteen sheep were randomly assigned to two groups. In group A (n = 7), the right ventricular cooling catheter system was used in addition to coronary cardioplegic perfusion and systemic hypothermia for myocardial protection. Group B (n = 7) served as a control group. In group A, the right ventricular temperatures were significantly lower than those of the control group (16.1 degrees +/- 0.3 degrees C versus 23.9 degrees +/- 0.4 degrees C; p less than 0.0001, Student's t test). The most common temperature range was 12 degrees to 18 degrees C (67.1%, frequency distribution analysis), and 63.2% of temperatures were below 16 degrees C. The catheter system also maintained the temperatures of the interventricular septum at a lower level than those recorded in the control group and prevented septal rewarming, which was significant in group B (from 16.5 degrees +/- 1.5 degrees C to 25.0 degrees +/- 0.9 degrees C; p less than 0.04, Mann-Whitney U test). Left ventricular temperatures were not changed by the catheter system. By better cooling the right ventricle and the septum, the right ventricular cooling catheter system should decrease the prevalence of right ventricular failure and allow more time to safely complete multiple coronary anastomoses in coronary artery bypass graft operations.

Residual clonable host cell detection for predicting engraftment of T cell depleted BMTs.

Rejection of T-depleted BMTs is predominantly mediated by alloreactive host T cells. A low but significant number of radiochemoresistant clonable T cells can be detected following a conventional cytoreductive protocol given prior to T-depleted BMT. Elimination of these cells increases the engraftment rate. We found no clonable T cells at the end of the conditioning regimen in 100 ml of peripheral blood from 47 patients who received an HLA-identical T-depleted BMT. None rejected the graft and none displayed mixed chimerism. In addition, although no clonable T cells were detected in nine patients who received a mismatched BMT, two rejected their graft. However, in three mismatched patients, who for clinical reasons received a modified pre-BMT schedule, the presence of host clonable T cells was associated with immunological rejection. These findings suggest that the detection of clonable T cells should prove a valuable indicator for optimising immunosuppression prior to T-depleted BMT.

Unusual split chimaerism after mismatched T-depleted BMT.

We report a case of haploidentical T-depleted BMT that engrafted durably after a highly immunosuppressive conditioning regimen. DNA polymorphism analysis showed that granulocytes and monocytes were donor type but T and B lymphocytes were host derived. Host tolerance to donor antigens was documented. The patient suffered from serious recurrent CMV infections until split chimaerism shifted to full donor type 2 years post-BMT. Seven years after BMT the patient remains in complete remission.

The role of megadose CD34+ progenitor cells in the treatment of leukemia patients without a matched donor and in tolerance induction for organ transplantation.

Throughout the 1980s, transplantation of unmodified (T cell-replete) bone marrow from full haplotype incompatible family donors was associated with an unsuccessful outcome because of graft failure and severe graft-versus-host disease (GVHD), at times affecting up to 90% of recipients. Although extensive T cell depletion of donor bone marrow was successful in preventing GVHD in children with severe combined immunodeficiency disease (SCID), results were disappointing in leukemic patients because the benefit of preventing GVHD was offset by graft failure. Resistance to engraftment appears to be mediated by host-derived cytotoxic T-lymphocyte precursors that survive supralethal conditioning. In the present paper, we review data that show that these genetic histocompatibility barriers can be overcome in stringent mouse models, employing lethally as well as sublethally irradiated recipients, by two major approaches that are synergistic to each other: escalation of hematopoietic progenitor cell dose and the use of nonalloreactive T cells. The former approach is already being successfully implemented in the treatment of leukemic patients.

Haploidentical stem cell transplantation for acute leukemia.

PREMISE: Since March 1993, 133 patients with high-risk acute leukemia (66 AML, 67 ALL) have received a megadose of T-cell depleted hematopoietic stem cells. The 1993-95 conditioning protocol included TBI, thiotepa, ATG and CY for 36 patients who received an inoculum made up of lectin-separated bone marrow and PBPCs. After 1995, to minimise the extra-hematological toxicity of the conditioning and eliminate GvHD, we substituted fludarabine for CY in the conditioning and PBPCs were depleted of T-cells by a positive selection of the CD34+ cells using CellPro (n=44 patients) or, since January 1999, CliniMacs (n = 53 patients). A later modification to the protocol in January 1999 was the suspension of post transplant G-CSF. WORK IN PROGRESS: We report here the results in the last 53 acute leukemia patients all of whom were transplanted under our modified protocol. Ages ranged from 9 to 62 years with a median of 38 years for the 33 patients with AML and 23 for the 20 with ALL. All were at high risk because 25 were actually in relapse at transplant, 16 were in second or later CR and even the 12 patients in CR1 were at high risk because of the unfavourable prognostic features. Overall 52/53 patients (98%) engrafted. The TBI-Fludarabine-based conditioning was well tolerated even in the 14 patients between 45 and 62 years of age. There was no veno-occlusive disease of the liver and the incidence of severe mucositis was low. Even though no post-transplant immunosuppressive therapy was given, acute GvHD grade > or = II occurred in only 4 cases and only one progressed to chronic GvHD. Overall, 16 patients (30%) have died of non-leukemic causes. Relapses occurred mainly in patients who were already in relapse at transplant (12/25). Only 3 of the 28 who were in any CR at transplant have so far relapsed. As our group has already shown, donor-vs-recipient NK cell alloreactivity exerts a specific graft-vs-AML effect in the absence of GvHD. In fact, leukemia relapse was largely controlled in AML recipients whose donor was NK alloreactive, with only 2 out of 16 relapsing. To date, 13 of 18 AML (72%) and 5 of 10 ALL (50%) who were in any CR at transplant, survive disease-free while 4 of the 15 patients (16%) in relapse at transplant survive. The probability of event-free survival for patients transplanted in CR is 60% in the 18 AML patients and 38% in the 10 ALL. The probability of EFS was significantly better in the 16 AML patients whose transplant included donor vs recipient NK cell alloreactivity than in those whose transplant did not (70% vs 7%). In conclusion, given our current results, the most suitable candidate for the full haplotype mismatched transplant should be in early stage disease and selection of an NK alloreactive donor is recommended.

Allogeneic transplantation across the HLA barriers.

In high-risk acute leukemia patients, a 10-fold increase in the dose of extensively T-cell-depleted hematopoietic stem cells ensures sustained full-donor engraftment of one-haplotype-mismatched transplants without graft-vs.-host disease. Since our first successful pilot study, which exploited the principle of a megadose stem cell transplant, our efforts have concentrated on developing new conditioning regimens, optimizing graft processing and improving the post-transplant immunologic recovery. The results so far achieved in more than 100 high-risk acute leukemia patients show that haploidentical transplantation is now a clinical reality. Because virtually all patients in need of a hematopoietic stem cell transplant have a full-haplotype-mismatched family donor, a T-cell-depleted mismatched transplant can be offered with curative intent, thus extending allogeneic transplantation procedures to virtually all candidates.

Cellular and humoral immunity in psoriatic patients.

The degree of cellular immunity was found to be reduced in about 23% of 56 psoriatics, especially so in those with flexural and arthropathic lesions. Humoral immunity was only slightly reduced. Lysozyme activity levels in serum were normal, while those of healthy skin were depressed in 6 patients.

Fibrin adhesive: clinical application in coronary artery bypass graft surgery.

Fibrin adhesive was used 72 times in a group of 67 patients undergoing elective coronary artery bypass graft surgery. The indications were prophylactic sealing of potential sources of bleeding, topical hemostasis (control of bleeding sites dangerous or difficult to suture), and fixation of the graft in the optimal position. The method of glue application under varying circumstances is described and the results are reported. This experience suggests that in some cases the glue expedites the operation and makes it safer. We conclude that the fibrin sealing represents a valid aid in coronary artery bypass graft surgery.

Lymphocyte surface antigens: a longitudinal study during the first month of human life.

A longitudinal study on human T lymphoid surface antigens was performed on blood samples from 6 infants during their first month of life. Although the results indicate a sudden increase in the percentage of OKT3+ and E-RF+ cell types a few hours after birth and a less rapid decrease of OKT6+ and OKT9+ circulating cells, high levels of OKT10+ cells persisted. This finding suggests that infant blood contains immature phenotypic T lymphocytes after birth.