HLA-mismatched haploidentical transplantation using low-dose anti-thymocyte globulin (ATG: thymoglobulin)

Objectives: To clarify optimal strategies for human leukocyte antigen (HLA)-mismatched haploidentical hematopoietic stem cell transplantation (HSCT).

Methods: Twelve patients who underwent HSCT from a haploidentical related donor using low-dose thymoglobulin were analyzed retrospectively. Thymoglobulin was added to conditioning regimens at 2.5?mg/kg/day for 2 days (days ?4 and ?3). Prophylaxis against graft-versus-host disease (GVHD) was performed with cyclosporine and methotrexate.

Results: The median age of the patients was 33 years. Six patients had previous allogeneic HSCT, and HSCT was performed in non-remission for nine patients. All patients but one, who died due to early infection, achieved neutrophil engraftment at a median of 17 days with complete donor-type chimerism. Acute and chronic GVHD were observed in six and five patients, respectively, but no patients died of GVHD-associated complication. No one developed cytomegalovirus disease, but Epstein–Barr virus-related lymphoproliferative disorder was observed in one patient. Long-term survival in remission without immunosuppressive agents are observed in two patients who underwent HSCT in remission, but the majority of patients who underwent HSCT in non-remission experienced disease progression.

Conclusion: Haploidentical HSCT could be performed with thymoglobulin at 5?mg/kg, with the balance between GVHD and relapse rate. The dose reduction of thymoglobulin may be considered for advanced hematological malignancy.     

Progressive multifocal leukoencephalopathy after T‐cell replete HLA‐haploidentical transplantation with post‐transplantation cyclophosphamide graft‐versus‐host disease prophylaxis

A 52‐year‐old man suffered from progressive multifocal leukoencephalopathy (PML) after human leukocyte antigen (HLA)‐haploidentical transplantation with post‐transplantation cyclophosphamide (PTCY). Mirtazapine, mefloquine, and cytarabine failed to improve his symptoms, and he finally died 4.5 months after PML onset. This is the first case report of a patient with PML after HLA‐haploidentical transplantation with PTCY. Although T‐cell replete HLA‐haploidentical transplantation with PTCY has enabled early immune reconstitution, PML should be considered if a patient's mental condition deteriorates.     

No indication of increased infection rates using low‐dose alemtuzumab instead of anti‐thymocyte globulin as graft‐versus‐host disease prophylaxis before allogeneic stem cell transplantation

Background

Alemtuzumab as part of the conditioning protocol is effective in reducing graft‐versus‐host disease (GvHD), but may be associated with increased infection rates, especially when using high doses (ie, 100 mg).

Methods

We performed a retrospective, single‐center, case‐control study analyzing the rates of neutropenic fever, cytomegalovirus (CMV) reactivation, Epstein‐Barr virus (EBV) reactivation, clinical manifest toxoplasmosis, and clinical manifest human herpesvirus‐6 (HHV6) infection using low‐dose alemtuzumab in comparison with anti‐thymocyte globulin (ATG) as GvHD prophylaxis before allogeneic stem cell transplantation. Forty‐four patients transplanted from unrelated donors between 2001 and 2012 were matched by age, diagnosis, and conditioning regimen and treated either with alemtuzumab 10 mg at day ?2 (respectively, 20 mg in case of mismatch transplantation) or ATG. ATG Fresenius (10 mg/kg for 3 days) or Thymoglobulin (2 mg/kg for 3 days) were used.

Results

Rates of CMV reactivation, EBV reactivation, and clinical manifest HHV6 infection or toxoplasmosis did not differ significantly between both groups until 2 years after transplantation. No case of post‐transplant lymphoproliferative disorder was observed. Also, rates of neutropenic fever during inpatient treatment after transplantation did not differ significantly in both groups.

Conclusion

We saw no indication of increased infections rates when using low‐dose alemtuzumab as GvHD prophylaxis before allogeneic stem cell transplantation in this retrospective analysis.     

Experts’ considerations on HLA‐haploidentical stem cell transplantation

Recently, novel strategies to control graft‐versus‐host disease and facilitate engraftment have allowed an increasing number of human leukocyte antigen (HLA)‐haploidentical hematopoietic stem cell transplantation (haploHSCT) to be performed. A meeting was convened to review the biological rationale and the clinical results of various T‐cell‐depleted (TCD) and T‐cell‐replete (TCR) HLA‐haploidentical ‘transplant platforms’. The objective of the meeting was to promote discussion and consent among leading researchers in the field on three main crucial issues for haploHSCT: (i) eligibility criteria, (ii) choice of the most suitable donor, and (iii) choice of the most appropriate transplant platform. The experts in attendance agreed that a patient who is eligible for an allogeneic transplant and lacks an HLA‐identical sibling or an HLA‐matched unrelated donor should be considered for an alternative donor transplant. Together with the experience of the individual center, the most important decision criteria in choosing an alternative donor source should be the rapidity of transplantation so as to avoid disease relapse/progression. The choice of the mismatched donor should be driven by younger age, ABO blood group compatibility, and Cytomegalovirus status. If a TCD transplant is planned, NK‐alloreactive donors and/or the mother should be preferred. Prospective comparative studies are needed to establish the relative efficacy of different transplant platforms. However, expertise in stem cell manipulation and in adoptive immunotherapy is essential if a TCD transplant platform is chosen.     

Pharmacokinetics of alemtuzumab after haploidentical HLA-mismatched hematopoietic stem cell transplantation using in vivo alemtuzumab with or without CD52-positive malignancies

We recently reported that the addition of in vivo alemtuzumab to the conditioning regimen enables 2- or 3-locus-mismatched hematopoietic stem cell transplantation without an excessive risk of graft rejection or graft-versus-host disease. In a later series of patients, however, one patient with refractory chronic lymphocytic leukemia with large residual tumors at transplantation developed graft rejection. While the peak alemtuzumab concentration in the previous patients without graft rejection was higher than 5 micro g/ml, the peak alemtuzumab concentration in this patient was only 1.44 micro g/ml. We considered that alemtuzumab was bound to the large residual tumors, which resulted in a low blood concentration of alemtuzumab. Therefore, it is important to debulk tumors before the conditioning regimen for patients with refractory CD52-positive hematological malignancies, or the dose of alemtuzumab should be adjusted by monitoring the blood concentration, when alemtuzumab is used for in vivo T-cell depletion in 2- or 3-locus-mismatched transplantation.     

Inhibitory killer cell immunoglobulin‐like receptor (iKIR) mismatches improve survival after T‐cell‐repleted haploidentical transplantation

Alloreactivity triggered by interaction between killer cell immunoglobulin‐like receptors (KIRs) and natural killer (NK) cells plays a role in the graft‐versus‐tumor effect after hematopoietic stem cell transplantation (SCT). Our aim in this study was to evaluate this role in the setting of T‐cell‐repleted haploidentical SCT with postinfusion high‐dose cyclophosphamide (PT‐Cy). We included 33 patients. Among patient–donor pairs with at least 1 inhibitory KIR (iKIR) gene mismatch, event‐free survival (EFS) and cumulative incidence of relapse 1 year after transplant were significantly better (85% vs. 37% [P = 0.008] and 18% vs. 46% [P = 0.041], respectively). A subanalysis in 12 patients with Hodgkin's lymphoma (HL) showed an improvement in EFS 1 year after transplant in those patients with KIR ligand mismatch (100% vs. 25%, P = 0.012), although overall survival (OS) was not affected (85% vs. 80%, P = 0.2). Eight of 12 patient–donors pairs presented iKIR mismatches. Of note, this outcome was better in the small subgroup, both for EFS (100% vs. 25%, P = 0.012) and for OS (100% vs. 37%, P = 0.004). Our data suggest that in the setting of T‐cell‐repleted haploidentical SCT with PT‐Cy, iKIR mismatch is associated with improved survival, with particularly good results for both iKIR and KIR ligand mismatches in patients with HL.     

Biopsy‐proven adenoviral diarrhea responding to low‐dose cidofovir

Abstract: We present a case of diarrhea secondary to biopsy‐proven adenovirus (ADV) infection after autologous peripheral hematopoietic stem cell transplant for multiple myeloma. The patient had a negative plasma polymerase chain reaction for ADV and a dramatic clinical response to low‐dose cidofovir. To our knowledge, this is the first report in an adult hematopoietic stem cell recipient of the use of low‐dose cidofovir to treat proven ADV gastrointestinal infection.     

Haploidentical transplantation compared with matched sibling and unrelated donor transplantation for adults with standard‐risk acute lymphoblastic leukaemia in first complete remission

We retrospectively investigated outcomes of haploidentical donor (HID) transplant for adults with standard‐risk acute lymphoblastic leukaemia (ALL) in first complete remission (CR1) compared with human leucocyte antigen (HLA)‐matched sibling donor (MSD) and HLA‐matched unrelated donor (MUD) transplants. A total of 348 adult patients were enrolled, including 127 HID, 144 MSD and 77 MUD recipients. The cumulative incidence of grade II–IV acute graft‐versus‐host disease (aGVHD) was 39·5%, 24·0% and 40·3% for HID, MSD and MUD, respectively (P = 0·020). However, there was no difference in grade III–IV aGVHD (11·4%, 7·7%, 13·5%, respectively, P = 0·468). The 5‐year cumulative transplant‐related mortality was 16·4%, 11·6% and 19·6% (P = 0·162), the 5‐year relapse rate post‐transplantation was 14·8%, 21·1% and 16·7% (P = 0·231), the 5‐year overall survival was 70·1%, 73·7% and 69·8% (P = 0·525), and the 5‐year disease‐free survival was 68·7%, 67·3% and 63·7%, respectively (P = 0·606). Furthermore, the 3‐year GVHD‐free, relapse‐free survival was not different (50·8%, 54·9% and 52·2%, respectively, P = 0·847). Our results indicate that the outcomes of HID transplants are equivalent to those of MSD and MUD, and that HID transplantation is a valid alternative for standard‐risk adults with ALL in CR1 who lack matched donors.     

Toxoplasma‐induced hemophagocytic lymphohistiocytosis after haploidentical allogeneic stem cell transplantation

Hemophagocytic lymphohistiocytosis (HLH) is a disorder of immune regulation, manifested by fever, pancytopenia, hyperferritiniemia, hypertriglyceridemia, and extensive hemophagocytosis involving the bone marrow and spleen. HLH can occur in adults with an underlying hematopoietic malignancy, or with systemic infections. HLH following hematopoietic stem cell transplantation (HSCT) is unusual, and the diagnosis may be challenging particularly because the diagnostic criteria in the HLH‐2004 guidelines overlap with common post‐transplant complications such as engraftment syndrome, graft‐vs‐host disease, and infections. HLH is commonly triggered by viral, bacterial and, less commonly, parasitic infections. Following HSCT, patients with latent Toxoplasma infection may develop systemic disease secondary to reactivation, and rarely this may lead to a HLH physiology, with a very high mortality rate. Herein we describe the successful management of disseminated toxoplasmosis associated with life‐threatening HLH using tocilizumab and antimicrobial therapy.     

High incidence of engraftment syndrome after haploidentical allogeneic stem cell transplantation

We determined the incidence, clinical manifestations, and outcomes of engraftment syndrome (ES) in haploidentical stem cell transplantation (SCT) recipients. We compared the incidence of ES between the patient group that received haploidentical SCT (n = 516) and the patient group that received HLA‐identical sibling SCT (n = 393). The transplantations were performed in the Peking University People's Hospital in the period between October 2001 and October 2012. The ES incidence data were collected retrospectively. Patients that presented non‐infectious fever or skin rash within the 24‐h window before or after the beginning of neutrophil recovery were diagnosed with ES in accordance with the Maiolino criteria. ES incidence in haploidentical SCT recipients (21.9%) was significantly higher than that in HLA‐identical sibling SCT recipients (2.0%; P < 0.001). Major symptoms included fever (119/121, 98.3%), skin rash (98/121, 81.0%), and diarrhea (51/121, 42.1%), with the median time of +10 d (range: 6–20 d). The median C‐reactive protein level of the ES group (99.0 mg/L; n = 13) was significantly higher than that of the non‐ES group (13.9 mg/L; n = 38; P < 0.001). Similarly, the results showed that the median C3 plasma concentration of the ES group (1.30 g/L) was higher than that of the non‐ES group (1.16 g/L, P = 0.003). ES was not associated with non‐relapse mortality or overall survival. High incidence of ES was observed in haploidentical SCT recipients; however, ES did not predict poor clinical outcomes.     

Comparison of transplant outcomes between haploidentical transplantation and single cord blood transplantation in non-remission acute myeloid leukaemia: A nationwide retrospective study

Allogeneic haematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for some patients with acute myeloid leukaemia (AML) who are refractory to chemotherapy. Cord blood transplantation (CBT) is a reasonable option in such cases because of its rapid availability. Recently, a growing number of human leucocyte antigen (HLA)-haploidentical related donor HSCTs (haplo-HSCTs) have been performed, although its effectiveness remains undetermined. Using the Japanese nationwide transplantation registry data, we identified 2438 patients aged ≥16 years who received CBT or haplo-HSCT as their first transplant for non-remission AML between January 2008 and December 2018. After 2:1 propensity score matching, 918 patients in the CBT group and 459 patients in the haplo-HSCT group were selected. In this matched cohort, no significant difference in overall survival (OS) was observed between the CBT and haplo-HSCT groups (hazard ratio [HR] of haplo-HSCT to CBT 1.02, 95% confidence interval [CI] 0.89–1.16). Similarly, no significant difference in the cumulative incidence of relapse (HR 1.09, 95% CI 0.93–1.28) or non-relapse mortality (HR 0.94, 95% CI 0.76–1.18). Subgroup analysis showed that CBT was significantly associated with preferable OS in patients receiving myeloablative conditioning. Our data showed comparable outcomes between haplo-HSCT and CBT recipients with non-remission AML.