Strong humoral response after Covid-19 vaccination correlates with the common HLA allele A*03:01 and protection from breakthrough infection.

Few data exist on the role of genetic factors involving the HLA system on response to Covid-19 vaccines. Moving from suggestions of a previous study investigating the association of some HLA alleles with humoral response to BNT162b2, we here compared the HLA allele frequencies among weak (n = 111) and strong (n = 123) responders, defined as those healthcare workers with the lowest and the highest anti-Spike antibody levels after vaccination. Individuals with clinical history of Covid-19 or positive anti-nucleocapside antibodies were excluded. We found the common HLA-A*03:01 allele as an independent predictor of strong humoral response (OR = 12.46, 95% CI: 4.41-35.21, p < 0.0001), together with younger age of vaccines (p = 0.004). Correlation between antibody levels and protection from breakthrough infection has been observed, with a 2-year cumulative incidence of 42% and 63% among strong and weak responders, respectively (p = 0.03). Due to the high frequency of HLA-A*03:01 and the need for seasonal vaccinations against SARS-CoV-2 mutants, our findings provide useful information about the inter-individual differences observed in humoral response after Covid-19 vaccine and might support further studies on the next seasonal vaccines.

Anti-CD38 monoclonal antibody impairs CD34+ mobilization and affects clonogenic potential in multiple myeloma patients.

BACKGROUND: Induction with daratumumab-based regimens followed by autologous stem cell transplantation is the current standard for newly diagnosed multiple myeloma (NDMM) patients eligible for intensive chemotherapy. However, concerns emerged regarding potential negative effects following daratumumab-based treatment on CD34+ mobilization. We here compared CD34+ mobilization and clonogenic potential between daratumumab and non-daratumumab based therapy without upfront plerixafor administration among patients affected by NDMM. MATERIALS AND METHODS: Clinical, mobilization and clonogenic data from 41 consecutively enrolled NDMM patients were analyzed. Patients underwent collection of autologous CD34+ by apheresis at the ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy, from January 2021 to March 2023. Clonogenicity analysis was performed on BFU-E and CFU-GM. RESULTS: Seventy-five percent of daratumumab-treated patients underwent >1 apheresis, compared to 24% of non-daratumumab patients (p=0.0017). Daratumumab-treated patients had significantly lower CD34+ count (mean 38 vs 79/µL, respectively; p=0.0011), with a median CD34+ harvest of 3.98×106/kg (range 1.68-9.18) vs 6.87×106/kg (range 1.63-16.85) in non-daratumumab-treated (p=0.0006). In multivariate analysis the likelihood of undergoing >1 apheresis was significantly higher in older patients (OR 1.2, 95% CI 1-1.4, Z=2.10, p=0.03) and daratumumab-treated patients (OR 15, 95% CI 2.8-129, p=0.004). Moreover, daratumumab-based induction therapy demonstrated an independent negative association with BFU-E colony formation (p=0.0148), even when accounting for patient age and CD34+ levels. DISCUSSION: Our findings underscore the impact of daratumumab-based treatment on CD34+ mobilization in a real-life, upfront plerixafor-free population of NDMM patients. Higher probability of requiring multiple apheresis occurred among daratumumab-treated patients. Interestingly, the observation that daratumumab might negatively impact BFU-E colony formation, independent of CD34+ cell count, offers novel biological perspectives. Appropriate strategies should be adopted by the Apheresis teams to mitigate these potential negative effects.

[Unrelated donor selection for allogeneic hematopoietic stem cell transplantation: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]. / Choix d'un donneur non apparenté en vue d'une allogreffe de cellules souches hématopoïétiques : recommandations de la Société francophone de greffe de moelle et de thérapie cellulaire (SFGM-TC).

The selection of a donor is an essential element in allogeneic hematopoietic stem cell transplantation. In the absence of an HLA-matched related donor, the selection of an unrelated donor is considered, and is currently the most common type of allogenic donor used in practice. Many criteria are considered for the selection when multiple donors are available, particularly in case of partial match. The aim of this workshop is to assist in the selection of an unrelated donor, in keeping with recent data from the literature.

Histocompatibility assessment in hematopoietic stem cell transplantation: recommendations from the Italian Association of Immunogenetics and Biology of Transplantation (Associazione Italiana di Immunogenetica e Biologia dei Trapianti - AIBT).

The outcome of allogeneic hematopoietic stem cell transplantation (HSCT) is significantly influenced by the degree of HLA histocompatibility between donor and recipient. To provide shared indications for required histocompatibility testing and interpretation before HSCT, the Italian Society for Immunogenetics and Transplantation Biology (Associazione Italiana di Immunogenetica e Biologia dei Trapianti [AIBT]) gathered members and created a working group to discuss and develop recommendations for histocompatibility assessment in HSCT.After a review of the literature and multiple panel discussions, AIBT developed up-to-date recommendations for the resolution levels of HLA typing, histocompatibility definitions of patients and donors, importance of anti-HLA antibodies, and significance of NK alloreactivity, which are reported in this document. These recommendations have been shared with the Italian Group for Bone Marrow Transplantation (Gruppo Italiano per il Trapianto di Midollo Osseo, cellule staminali emopoietiche e terapia cellulare [GITMO]) and the Italian National Center for Transplantation (Centro Nazionale Trapianti [CNT]). Notably, the increased use of HLA-mismatched transplantation (i.e., mismatched unrelated, haploidentical) in recent years has made these indications even more relevant for the standardization and improvement of quality of care.This document represents a useful instrument for health care workers involved in the field of HSCT, enhancing synergy with transplant physicians and enabling greater optimization of the available resources.

Managing leukapheresis in adult and pediatric patients eligible for chimeric antigen receptor T-cell therapy: suggestions from an Italian Expert Panel.

Chimeric antigen receptor (CAR) T-cell therapy relies on T cells engineered to target specific tumor antigens such as CD-19 in B-cell malignancies. In this setting, the commercially available products have offered a potential long-term cure for both pediatric and adult patients. Yet manufacturing CAR T cells is a cumbersome, multistep process, the success of which strictly depends on the characteristics of the starting material, i.e., lymphocyte collection yield and composition. These, in turn, might be affected by patient factors such as age, performance status, comorbidities, and previous therapies. Ideally, CAR T-cell therapies are a one-off treatment; therefore, optimization and the possible standardization of the leukapheresis procedure is critical, also in view of the novel CAR T cells currently under investigation for hematological malignancies and solid tumors. The most recent Best Practice recommendations for the management of children and adults undergoing CAR T-cell therapy provide a comprehensive guide to their use. However, their application in local practice is not straightforward and some grey areas remain. An Italian Expert Panel of apheresis specialists and hematologists from the centers authorized to administer CAR T-cell therapy took part in a detailed discussion on the following: 1) pre-apheresis patient evaluation; 2) management of the leukapheresis procedure, also in special situations represented by low lymphocyte count, peripheral blastosis, pediatric population <25 kg, and the COVID-19 outbreak; and 3) release and cryopreservation of the apheresis unit. This article presents some of the important challenges that must be faced to optimize the leukapheresis procedure and offers suggestions as to how to improve it, some of which are specific to the Italian setting.

Human Leucocyte Antigen System and Selection of Unrelated Hematopoietic Stem Cell Donors: Impact of Patient-Donor (Mis)matching and New Challenges with the Current Technologies.

The selection of hematopoietic stem cell donors for allogeneic transplantation (allo-HSCT) is mainly driven by human leucocyte antigen (HLA) matching between patient and donor, with HLA-identical matched siblings being the preferred choice in most situations. Although other clinical and demographical variables matter, especially, donor age, which is unequivocally associated with better transplant outcomes, the histocompatibility criteria have a central role in the search for the best donor, particularly in the setting of unrelated allo-HSCT where HLA disparities between patient and donor are frequent. The present review is focused on the role of HLA incompatibilities on patient outcome according to the most recent literature, in an attempt to guide transplant physicians and search coordinators during the process of adult unrelated-donor selection. The technological progresses in HLA typing, i.e., with next-generation sequencing (NGS), now allow disclosing a growing number of HLA incompatibilities associated with a heterogeneous and sometimes unknown spectrum of clinical severity. Their immunogenic characteristics, i.e., their position inside or outside the antigen recognition domain (ARD), their permissiveness, their intronic or exonic nature and even the expected expression of the HLA loci where those mismatches occur, will be presented and discussed here, integrating the advances in the immunobiology of transplantation with survival and toxicity outcomes reported in the most relevant studies, within the perspective of improving donor selection in the current practice.

Selected memory T cells infused post-haploidentical hematopoietic stem cell transplantation persist and hyperexpand.

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with post-transplant cyclophosphamide is a curative treatment for many hematological malignancies, yet a majority of patients still suffers from recurrent infections. Post-transplant infusion of memory T-cells could potentially enhance immunological protection without increasing the risk of eliciting acute graft-versus-host disease, which is mainly induced by naïve T-cells. Here, we performed longitudinal analysis of the lymphocyte compartment in 19 patients who underwent haplo-HSCT previously enrolled in a phase II prospective clinical trial (www.clinicaltrials.gov as #NCT04687982), in which they received post-transplant CD45RA-depleted donor lymphocyte infusions (DLI). T-cell receptor sequencing analysis showed that, surprisingly, CD45RA-depleted DLI do not increase T-cell clonal diversity, but lead to prominent expansion of a selected number of infused memory T-cell clones, suggesting recruitment of these cells in the immune response. Pathogen-specific memory T-cells, including cytomegalovirus (CMV)-specific cells, were engrafted and were able to persist for at least 1 month. Deep immunophenotyping revealed strong polyfunctional effector CMV-specific T-cell responses in the majority of patients, with their expansion correlating with the frequency of CMV-specific cells in the donor. These findings provide a rationale behind the suggested improved protection against viral infections in patients receiving CD45RA-depleted DLI.

[Diagnosis, prophylaxis and therapeutic management of acute GVH: Guidelines from the SFGM-TC]. / Diagnostic, prophylaxie et prise en charge thérapeutique de la GVH aiguë : recommandations de la SFGM-TC.

Acute GVHD is a potentially severe complication of hematopoietic stem cell transplantation, responsible for morbidity and mortality that can affect the prognosis after transplantation. Within the framework of the 12th workshop of practice harmonization of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC), diagnostic modalities of acute GVHD are updated. The conventional prevention (depending on donor, conditioning, and stem cell source) and treatment schemes (depending on affected organ and intensity) of aGVHD are clarified, and new therapeutic options are discussed.

Polymorphism of the HLA system and weak antibody response to BNT162b2 mRNA vaccine.

The polymorphism of the HLA system has been extensively studied in COVID-19 infection, however there are no data about the role of HLA on vaccine response. We report here the HLA-A, -B, -C, and DRB1 allelic frequencies of n = 111 individuals after BNT162b2 mRNA vaccine, selected on the basis of lower antibody levels (<5% percentile) after the second dose among a total of n = 2569 vaccinees, and compare them with the frequencies of a reference population. We found that differences in the frequencies of the alleles HLA-A*03:01, A*33:03, B*58:01 and at least one haplotype (HLA-A*24:02~C*07:01~B*18:01~DRB1*11:04) are associated with a weaker antibody response after vaccination, together with the age of vaccinees. Our results might suggest a role played by some HLA alleles or haplotypes in antibody production after the BNT162b2 mRNA vaccine, giving insights into the tracking of potentially susceptible individuals across populations. Further studies are needed to better define our exploratory findings and dissect the role of HLA polymorphism on response to anti-COVID-19 vaccines.

SARS-COV-2 screening in allogeneic hematopoietic stem cell donors: Implications for the evaluation process and eligibility

Abstract Introduction Soon after the onset of the SARS-CoV-2 pandemic, viral screening by nasopharyngeal swab became mandatory for allogeneic hematopoietic stem cell (HSC) donor eligibility. Methods We described our monocenter experience with allogeneic HSC donors from February 1 to the October 31, 2020 to verify whether the introduction of SARS-CoV-2 screening altered the donor eligibility and/or entailed a prolongation of the evaluation process. Results A total of 21 allogeneic HSC donors were screened during the above-mentioned period upon request by the local transplant physicians or by the Italian Bone Marrow Donor Registry; among the HSC donors (n = 17) who completed the eligibility process and further received the nasopharyngeal swab, all but one were negative for the presence of SARS-CoV-2. The positive donor remained asymptomatic for the whole duration of the infection, which lasted six weeks. However, he was temporarily excluded from donation. The median duration of the evaluation process was not significantly different, compared to the same period of 2019 (p-value = 0.11). Conclusion The mandatory SARS-CoV-2 screening in allogeneic HSC donors allowed for the detection of 6% positivity in this monocenter series over a 9-month period. Despite the inconvenience of this unexpected non-eligibility, the exclusion of a SARS-CoV-2 positive donor represented an important safety measure for the donor, with respect to a new and still partially unknown virus. The screening did not alter the length of the donor evaluation and thus, did not cause a delay in the eligibility process.

SARS-COV-2 screening in allogeneic hematopoietic stem cell donors: Implications for the evaluation process and eligibility.

INTRODUCTION: Soon after the onset of the SARS-CoV-2 pandemic, viral screening by nasopharyngeal swab became mandatory for allogeneic hematopoietic stem cell (HSC) donor eligibility. METHODS: We described our monocenter experience with allogeneic HSC donors from February 1 to the October 31, 2020 to verify whether the introduction of SARS-CoV-2 screening altered the donor eligibility and/or entailed a prolongation of the evaluation process. RESULTS: A total of 21 allogeneic HSC donors were screened during the above-mentioned period upon request by the local transplant physicians or by the Italian Bone Marrow Donor Registry; among the HSC donors (n = 17) who completed the eligibility process and further received the nasopharyngeal swab, all but one were negative for the presence of SARS-CoV-2. The positive donor remained asymptomatic for the whole duration of the infection, which lasted six weeks. However, he was temporarily excluded from donation. The median duration of the evaluation process was not significantly different, compared to the same period of 2019 (p-value = 0.11). CONCLUSION: The mandatory SARS-CoV-2 screening in allogeneic HSC donors allowed for the detection of 6% positivity in this monocenter series over a 9-month period. Despite the inconvenience of this unexpected non-eligibility, the exclusion of a SARS-CoV-2 positive donor represented an important safety measure for the donor, with respect to a new and still partially unknown virus. The screening did not alter the length of the donor evaluation and thus, did not cause a delay in the eligibility process.

Results of the RENAISSANCE Study: REsponse to BNT162b2 COVID-19 vacciNe-short- And long-term Immune reSponSe evAluatioN in health Care workErs.

OBJECTIVE: To evaluate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) anti-spike (S) IgG antibody production after vaccination with BNT162b2 and the protection from symptomatic breakthrough infections in health care workers. METHODS: This prospective observational study (RENAISSANCE) had as a primary end point the evaluation of serologic response to BNT162b2 14 days after a second dose. SARS-CoV-2 anti-S IgG antibodies were evaluated with LIAISON SARS-CoV-2 TrimericS IgG assay (DiaSorin S.p.A.), which is able to detect the presence of both binding and neutralizing antibodies for trimeric spike glycoprotein. Participants were recruited from February 1, 2021, to February 22, 2021. Occurrence of vaccine breakthrough infections was assessed by reverse transcription-polymerase chain reaction on symptomatic and contact cases up to June 6, 2021. RESULTS: Of 2569 staff evaluated, only 4 were nonresponders (0.16%; 95% CI, 0.04% to 0.41%). All 4 nonresponders were severely immunosuppressed and receiving treatment with mycophenolate mofetil or mycophenolic acid. At 14 days after the second dose, 67.5% (1733) of staff had anti-S IgG titers of 2000 BAU/mL or higher; 19.2% (494), between 1500 and 2000 BAU/mL; 9.8% (251), between 1000 and 1500 BAU/mL; and 3.4% (87), 1000 BAU/mL or lower. Women had a higher probability of having higher titers than men (64.5% [1044/1618] vs 58.3% [410/703]; P=.005). This was confirmed after adjustment for age group (odds ratio, 1.275; 95% CI, 1.062 to 1.531; P=.009). Four months after the end of the vaccination program, only 13 participants (0.26%) had experienced a breakthrough SARS-CoV-2 infection, including 1 nonresponder. This was the only participant requiring hospitalization for severe COVID-19. CONCLUSION: The vaccination campaign among health care workers at the ASST GOM Niguarda has resulted in a marked serologic response and reduction of incident COVID-19 cases. Yet, the lack of protection should not be overlooked in immunocompromised individuals.

Use of DPB1 T-cell epitope algorithm among italian transplant centers: A survey on behalf of Associazione Italiana di Immunogenetica e Biologia dei Trapianti.

The HLA-DPB1 locus has been demonstrated to have a significant role on patients' outcome after allogeneic HSCT, and the so-called T-cell epitope (TCE) algorithm has been incorporated in international guidelines for the selection of unrelated donors. The purpose of the present study is to measure, through a national survey conducted on behalf of the Associazione Italiana di Immunogenetica e Biologia dei Trapianti (AIBT), the extent of awareness and use of HLA-DPB1 TCE-based algorithms during the donor search. 89% of the HLA laboratories answered to a short questionnaire and the results showed a progressive increase of the laboratories typing DPB1 in patients and their potential donors during the search (from 44% to 79% during the 2010-2019 period) as well as the application of a TCE-based algorithm for the donor choice whenever possible (from 24% to 65% during the same period). The DP-permissiveness status is detailed in the official HLA typing report by 12%, 32% and 50% of laboratories in 2010, 2015 and 2019, respectively. The present data indicate an encouraging raise in the awareness of the HLA-DPB1 role in unrelated donor selection; noteworthy, mentioning the TCE-based permissiveness status in the HLA typing report of each potential unrelated donor represents a notable mean to raise awareness among transplant physicians and to support them in their task of choosing the best donor. Nonetheless, despite the compelling evidence of the predictive ability of TCE-based algorithms, further efforts are still needed to extend its application to all transplant centers in Italy.

[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.

Feasibility and Efficacy of CD45RA+ Depleted Donor Lymphocytes Infusion After Haploidentical Transplantation With Post-Transplantation Cyclophosphamide in Patients With Hematological Malignancies.

Allogeneic stem cell transplantation from haploidentical donor using post-transplantation cyclophosphamide has been used to cure hematological diseases. Because of slow immunological reconstitution, there is an increased incidence of viral infection. The aim of our study was to prospectively evaluate the efficacy and the feasibility of a CD45RA+ depleted donor lymphocytes infusion (DLI) in terms of reduction of viral infection early after haploidentical transplantation. This a prospective single-center study. We enrolled 23 patients, of whom 19 were evaluable. Graft-versus-host disease (GVHD) prophylaxis was the same for all patients. The primary endpoint was 100-day cumulative incidence of viral infections. The primary endpoint was met, because the 100-day cumulative incidence of viral infection was 32%. The median time from transplantation to first CD45RA+ depleted DLI was 55 days (range, 46-63). 28% of patients had cytomegalovirus reactivation, no patients reactivated human herpesvirus-6; 1 patient developed BK virus related hemorrhagic cystitis. Most of the patients received the planned 3 infusions. Only 1 patient had development of grade 2 acute GVHD, and 2 patients had moderate chronic GVHD. All evaluable patients were off immunosuppressive therapy at last follow-up. The median follow-up was 12 months (range, 3-23), the 1-year overall survival and progression-free survival were 79% and 75%, respectively; the 100-day and 1-year non-relapse mortality were 5% and 12%, respectively. CD45RA+ depleted DLI are feasible in patients treated with haploidentical transplantation. The toxic profile is good with a low risk for development of both acute and chronic GVHD.