HLA-DRB3/4/5 mismatches are associated with increased risk of acute GVHD in 10/10 matched unrelated donor hematopoietic cell transplantation.

Matching for HLA-A, -B, -C, and -DRB1 loci (8/8 match) is currently the gold standard for unrelated donor hematopoietic cell transplantation (HCT). In Europe, patients are also matched at the HLA-DQB1 loci (10/10 match). However, there is increasing evidence that matching at HLA-DRB3/4/5 loci may help to lower transplant-related morbidity and mortality. We therefore investigated the impact of HLA-DRB3/4/5 mismatches on outcomes in 1975 patients who received a first 10/10 matched unrelated donor (MUD) HCT in France from 2000 to 2012 for a hematological malignancy. High-resolution typing was performed at HLA-A, -B, -C, -DRB1, -DQB1, -DPB1, and -DRB3/4/5 loci for all donor/recipient pairs. Compared with DRB3/4/5-matched pairs, patients who received a MUD HCT from a DRB3/4/5 mismatched donor had a significantly increased risk of grade II-IV acute graft-versus-host disease (aGVHD) (Adjusted Hazard Ratio (HR) 1.43 (1.07 to 1.90)) associated with lower graft-versus-host disease-free and relapse-free survival (GRFS) (Adjusted HR 1.20 (1.02 to 1.42)). Conversely, we observed no differences in terms of chronic GVHD, nonrelapse mortality, relapse and overall survival. However, we believe that patients stand to benefit from DRB3/4/5 loci being considered for unrelated donor selection to improve GRFS and then quality of life after unrelated HCT.

Identification of the novel HLA-DRB1*14:253 allele by next-generation sequencing.

HLA-DRB1*14:253 differs from DRB1*14:54:01 by one nucleotide substitution in codon 233 in exon 5.

Incidence of donor-specific antibodies in kidney transplant patients following conversion to an everolimus-based calcineurin inhibitor-free regimen.

Scarce data exist regarding the incidence of donor-specific antibodies (DSAs) in kidney transplant patients receiving everolimus-based immunosuppression without calcineurin inhibitors (CNIs). The aim of this retrospective case-control study was to compare the incidence of de novo DSAs in patients converted to an everolimus-based regimen without CNIs with that seen in patients maintained on CNIs. Sixty-one DSA-free kidney transplant patients who had been converted to an everolimus-based regimen (everolimus group) were compared to 61 other patients maintained on CNIs-based regimen (control group). Patients were matched according to age, gender, induction therapy, date of transplantation, and being DSA-free at baseline. At last follow-up, the incidence of DSAs was 9.8% in the everolimus group and 5% in the control group (p = ns). In the everolimus group, the increased incidence of DSAs between baseline and last follow-up was statistically significant. Antibody-mediated rejection occurred in 6.5% in the everolimus group and 0% in the CNIs group. The incidence of DSAs is numerically increased in kidney transplant patients treated with an everolimus-based without CNIs. A study including a larger number of patients is required to determine whether a CNI-free everolimus-based immunosuppression significantly increases DSAs formation.

Identification of the novel HLA-DRB1*04:335 allele by next-generation sequencing.

HLA-DRB1*04:335 differs from DRB1*04:01:01 by one nucleotide substitution in codon 28 in exon 2.

Identification of the novel HLA-DQA1*01:82 allele by next-generation sequencing.

HLA-DQA1*01:82 differs from DQA1*01:03:01 by one nucleotide substitution in codon 49 in exon 2.

Identification of the novel HLA-DQB1*06:386 allele by next-generation sequencing.

HLA-DQB1*06:386 differs from DQB1*06:46 by one nucleotide substitution in Codon 130 in Exon 3.

Identification of the novel HLA-DQB1*03:471 allele by next-generation sequencing.

HLA-DQB1*03:471 differs from DQB1*03:02:01 by one nucleotide substitution in codon 142 in exon 3.

Identification of the novel HLA-DRB3*02:174 allele by next-generation sequencing.

HLA-DRB3*02:174 differs from DRB3*02:02:01 by one nucleotide substitution in codon 95 in exon 3.

Identification of the novel HLA-DPA1*01:49 allele by next-generation sequencing.

HLA-DPA1*01:49 differs from DPA1*01:03:01:04 by one nucleotide substitution in codon 119 in exon 3.

Identification of the novel HLA-DQB1*05:275 allele by next-generation sequencing.

HLA-DQB1*05:275 differs from DQB1*05:01 by one nucleotide substitution in codon 224 in exon 4.

[Definition and standardization of histocompatibility requests depending on patient course and donor type: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) and the Francophone Society of Histocompatibility and Immunogenetics (SFHI)]. / Définition et standardisation des bilans d'histocompatibilité en fonction du parcours du patient et du type de donneur : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC) et de la Société Francophone d'Histocompatibilité et Immunogénétique (SFHI).

Standardization of histocompatibility tests for allogeneic hematopoietic cell transplants, harmonization of information transmitted to clinicians are part of quality improvement and optimization of human and economic resources. New HLA typing technologies provide high-resolution information within a reasonable time frame. Knowledge of high-resolution HLA typing for the patient and their relatives is essential for a better interpretation of compatibilities. HLA-DPB1 typing must be considered in transplant field regardless of the donor type. The benefits of using search and match programs are considerable. It saves time and reduces additional typing costs by providing rapid information about the likelihood to identify a matched unrelated donor. A backup therapy considering alternative cell sources or treatment can therefore be quickly implemented. The importance of knowledge and consideration of patient immunization for donor choice was explored in previous workshops of the SFGM-TC (2018 and 2019). The published recommendations remain applicable. The routine follow-up protocol and in case of desensitization will be detailed here. This harmonization must be accompanied by the standardization of information to be returned to the clinician regarding the donor finding possibilities for the patient. This will guarantee a similar quality level in every center.

Treatment of symptomatic transplant glomerulopathy with rituximab.

Kidney transplant glomerulopathy (TG) has a poor outcome as there are no known effective therapies. Therefore, we investigated whether rituximab therapy (RTx) could halt progression of established TG. Fourteen kidney-transplant patients (nine of whom were men), with median age of 54 (range: 30-74) years, of whom seven had biologic markers for HCV infection, underwent a kidney biopsy (KB) at 118 months post-transplant because of impaired allograft function, associated with albuminuria (95-13430 mg/day), within nephrotic-range albuminuria in seven patients. KBs showed no evidence of acute cellular rejection but showed TG. Donor-specific anti-HLA antibodies were present in six cases. When diagnosis of TG was made, patients were placed on rituximab therapy (RTx) (2-4 injections of 375 mg/m2 week), and other concurrent immunosuppression treatments were not modified. By last follow up post-RTx (30 months), seven (50%) patients had lost their kidney within 6-26 months and the other seven had stable creatinine (182 vs. 161 micromol/l; NS), and albuminuria had decreased from 2660 to 500 mg/day (P = 0.03). There was prolonged B-cell lymphopenia (from 71 to 0/mm3) whereas immunoglobulin G, A, M levels remained stable, and four patients (28.5%) experienced severe infectious complications. We conclude that long-term RTx in kidney-transplant patients with TG is associated with allograft function/stabilization in 50% of cases.

Successful retransplantation of a kidney allograft affected by thrombotic microangiopathy into a second transplant recipient.

The donor organ shortage has compelled transplant centers to use organs from nontraditional sources. One example is the reuse of a previously transplanted organ, such as a kidney or liver retrieved from a brain-dead allograft recipient. For the first time, we reused a previously transplanted kidney that experienced intractable recurrent thrombotic microangiopathy (TMA) from a living allograft recipient. Within a few weeks posttransplantation, a deceased kidney allograft recipient developed intractable severe recurrent idiopathic TMA in the allograft despite intensive plasma exchanges and steroid and rituximab therapy. This required nephrectomy to cure TMA. The index recipient was believed to have a well-functioning allograft despite TMA (serum creatinine, 1.36 mg/dL [120 micromol/L]) and microalbuminuria with albumin of 1.2 g/dL [12 g/L]), and it appeared mildly damaged on biopsy examination. After donor and recipient informed consents were obtained and after approval of the French Agency of Biomedicine, the TMA allograft was reused and transplanted into a recipient whose original kidney disease was polycystic kidney disease. The retransplantation was uneventful, and at 6 months posttransplantation, the ultimate recipient's serum creatinine level was 1.06 mg/L (97 micromol/L) and albuminuria was 0.5 g/dL (5 g/L). A routine kidney biopsy showed mild glomerular lesions. After allograft nephrectomy, the donor's hematologic TMA symptoms dissipated within 10 days. We conclude that a kidney allograft with TMA recurrence can be successfully retransplanted into another recipient with excellent kidney function while still curing the first recipient of recurrent TMA. This might increase the number of kidney allografts from extended criteria donors.

Rituximab therapy for acute humoral rejection after kidney transplantation.

A pilot study was performed on eight consecutive renal-transplant (RT) patients presenting with acute humoral rejection (AHR) to assess the efficacy of monoclonal anti-B cell antibodies, such as rituximab (375 mg/m weekly) for 3 to 5 consecutive weeks, in addition to plasma exchange (PE), steroids, mycophenolate mofetil, and tacrolimus. AHR was associated with increased serum creatinine, the appearance of donor-specific alloantibodies (DSA), and the presence of C4d in a transplant biopsy. After a follow-up of 10 months (range 7-23), patient and graft survivals were 100% and 75%, respectively. Renal function improved in six cases in which serum creatinine decreased from 297+/-140 to 156+/-53 micromol/L (P=0.015); graft loss occurred in two cases; and four patients had infectious complications. At last follow-up, DSA had disappeared or decreased in four cases. Rituximab therapy, in addition to PE, might be of benefit for RT patients presenting with AHR.

Platelet transfusion refractoriness in patients with acute myeloid leukemia treated by intensive chemotherapy.

Platelet transfusion refractoriness (PTR) is a major adverse event in the management of acute myeloid leukemia (AML). In a series of 897 adult patients with AML receiving intensive chemotherapy, we identified 41 patients (4.8%) with PTR. PTR was more frequently observed in parous women, patients with extra-medullary disease, a low white blood cell count, an infection, or hemophagocytic syndrome. Among the 31 patients with anti-human leucocyte antigen (HLA) antibodies, an HLA-matched donor was identified for 18 patients (58.1%). Median time between diagnosis of PTR and the first HLA-matched transfusion was 12.5days. HLA-matched transfusions induced a significant increment in platelet counts in 37% of cases. Thrombopoietin receptor agonists were given to 10 patients but did not shorten the duration of thrombocytopenia, reduce severe bleeding, or early death. Grade 3-4 bleeding events during induction, early death caused by bleeding, and death caused by bleeding at any time were significantly greater in patients that had platelet transfusion refractoriness (22% vs. 4.1%, P<0.0001; 12.2% vs. 1.4%, P=0.0006; and 24.4% vs. 5.3%, P<0.0001; respectively). PTR during chemotherapy for AML significantly increased the risk of early and late deaths caused by a severe bleeding event. Improved understanding of platelet destruction is needed to design mechanism-based therapeutic strategies.

Prognostic impact of viral reactivations in acute myeloid leukemia patients undergoing allogeneic stem cell transplantation in first complete response.

Cytomegalovirus (CMV) serological status of donor and recipient as well as CMV reactivation have been associated with a lower risk of relapse in acute myeloid leukemia (AML) patients after allogeneic stem cell transplantation (alloSCT). Since immunosuppression following transplant allows resurgence of many other viruses, we retrospectively evaluated the impact of viral reactivations on relapse and survival in a cohort of 136 AML patients undergoing alloSCT in first remission from sibling (68%) or unrelated (32%) donors. Myeloablative and reduced-intensity conditioning regimen were given to 71 and 65 patients, respectively. Including CMV reactivations, at least 1 viral reactivation was recorded in 76 patients. Viral reactivations were associated with a lower risk of relapse (adjusted HR 0.14; 95% CI 0.07-0.30; P < 0.01), better disease-free survival (aHR 0.29; 95% CI 0.16-0.54; P < 0.01) but higher non relapse mortality. This translated into a better overall survival (aHR 0.44; 95%CI 0.25-0.77; P < 0.01) in patients who experienced viral reactivation. Thus, viral reactivations, including but not limited to CMV reactivation, are associated with a better outcome particularly with regard to the risk of relapse in AML patients undergoing alloSCT. New guidelines regarding the choice of donor according to the CMV serostatus are needed.

Anti-human leukocyte antigen immunization after early allograft nephrectomy.

INTRODUCTION: The occurrence of de novo anti-human leukocyte antigen (HLA) antibodies and donor-specific antibodies (DSAs) after early graft loss is not well known. The aims of this single-center study were to evaluate the incidence of de novo DSAs and non-DSA anti-HLA antibodies after allograft nephrectomy for early graft loss and to seek the predictive factors for the development of DSAs. MATERIALS AND METHODS: Thirty-two patients, who experienced an early graft loss (<3 months after transplantation) and required an allograft nephrectomy, and who were considered for retransplantation, were included in the study. Anti-HLA antibodies were assessed, using the Luminex assay, before transplantation, on day 15 and at months 1, 3, 6, and 9 after the nephrectomy, and then every 3 to 6 months until the last follow-up. RESULTS: The median time between transplantation and allograft nephrectomy was 2.5 (0-81) days. The median follow-up was 335 (30-1441) days. At month 9, postallograft nephrectomy, the incidence of DSAs was 56.6% (17/30). Anti-HLA class I and class II DSAs were detected, respectively, in 33.3% (10/30) and 30% (9/30) of patients. The incidence of de novo non-DSA anti-HLA antibodies was 64% (19/30): of these, 83.3% reacted to the donors' epitopes. Induction therapy (type and dose) and the time between transplantation and allograft nephrectomy did not influence the incidence of DSAs. No independent predictive factor for the development of DSAs was identified. CONCLUSION: Even after a short transplantation period, DSAs and non-DSA anti-HLA antibodies may develop in more than 50% of patients whose immunosuppression has been stopped after an allograft nephrectomy.

Donor-specific antibodies after ceasing immunosuppressive therapy, with or without an allograft nephrectomy.

BACKGROUND AND OBJECTIVES: Within the last few years, anti-human leukocyte antigen detection assays have significantly improved. This study asked, using the Luminex single-antigen assay, whether an allograft nephrectomy allowed donor-specific alloantibodies to appear that were not previously detected in the serum when the failed kidney was still in place. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: After losing the kidney allograft and stopping immunosuppressive therapy, the proportions of donor-specific alloantibodies and nondonor-specific alloantibodies were compared in patients who had (n=48; group I) and had not (n=21; group II) undergone an allograft nephrectomy. Allograft nephrectomies were performed at 150 days after kidney allograft loss, and the time between allograft nephrectomy and last follow-up was 538 ± 347 days. RESULTS: At kidney allograft loss, donor-specific alloantibodies were detected in three group II patients (14.2%) and six group I patients (12.5%). At last follow-up, donor-specific alloantibodies were detected in 11 patients (52.4%) without and 39 patients (81%) with an allograft nephrectomy (P=0.02). Anti-human leukocyte antigen class I donor-specific alloantibodies were positive in 23.8% of group II and 77% of group I patients (P<0.001); anti-human leukocyte antigen class II donor-specific alloantibodies were positive in 42.8% of group II and 62.5% of group I patients. Independent predictive factors for developing donor-specific alloantibodies after losing kidney allograft and stopping immunosuppressants were number of anti-human leukocyte antigen A/B mismatches at transplantation (zero versus one or more) and allograft nephrectomy. CONCLUSIONS: The development of donor-specific alloantibodies was significantly greater in patients with a failed kidney who had undergone an allograft nephrectomy compared with those patients who had not undergone allograft nephrectomy.

Impact of rituximab therapy on response to tetanus toxoid vaccination in kidney-transplant patients.

OBJECTIVES: Rituximab is used after kidney transplant to prevention or treat kidney-allograft rejection. However, the impact of rituximab on the ability of patients to respond to tetanus toxoid vaccination has not yet been studied. MATERIALS AND METHODS: The response to tetanus toxoid vaccination was analyzed in 39 kidney transplant recipients immunosuppressed by corticoids, antiproliferative agents, and/or calcineurin inhibitors. Thirteen patients had previously received rituximab (group 1), 26 patients had not (group 2). Response to control bacterial antigens and immunologic parameters (lymphocyte count, B-cell subsets, serum immunoglobulin level) were analyzed before and at 1 month after vaccination. Thirty healthy blood donors were used as controls for the before-vaccination immunologic parameters. RESULTS: Before vaccination, neither patient group differed from controls in serum levels of immunoglobulins and antibodies against bacterial antigens, but they did display lower levels of CD4 T cells and B cells compared with controls. Responders to the tetanus toxoid vaccination were slightly fewer in group 1 (4/13) than in group 2 (16/26), but the intensity of the anti-tetanus toxoid response was not significantly different between these 2 groups. None of the parameters studied at the time of vaccination (anti-tetanus toxoid level, peripheral B or CD4 T-cell count, memory B-cell subsets, treatment with rituximab, time since transplant) were associated with an ability to respond to vaccination. The ability to respond to vaccination and graft outcomes were not correlated in each patient group. CONCLUSIONS: Rituximab impaired the secondary immune response after tetanus toxoid vaccination, but did not abolish it in all patients.