Antibody, cell-mediated response and infection susceptibility in allogeneic hematopoietic stem cell recipients after COVID-19 mRNA vaccination.

BACKGROUND: Patients undergoing allogeneic stem-cell transplantation (allo-SCT) have reduced responses to vaccines due to immunosuppressive status linked to GvHD prophylaxis and treatment. In our study, we compared humoral responses to anti-SARS-CoV-2 mRNA vaccine, and infection onset, according to patients and transplant features; we also evaluated cellular response in patients without seroconversion. METHODS: We tested antibodies titer after second and third vaccine doses. Antibodies were detected through an immune-enzymatic assay. In a patients' subgroup without seroconversion, we tested cell-mediated responses evaluating interferon-gamma release by T-lymphocytes exposed to virus spike protein. RESULTS: Seroconversion rate increased from 66% at 30 days to 81% at 90 days after the second dose; it was 97% at 150 days after the third dose. We found a significant association between seroconversion after the second dose and two variables: shorter interval between allo-SCT and vaccination; ongoing immunosuppression. Twelve of 19 patients (63%) without antibodies after the second dose did not show cellular responses. Nineteen percent of patients developed SARS-CoV-2 infection after the third dose, with favorable outcome in all cases. Patients within 12 months after allo-SCT showed a significantly higher infection risk. CONCLUSIONS: Our study suggests that an interval shorter than 12 months between allo-SCT and first vaccine dose and/or ongoing immunosuppression were associated with humoral and cellular response deficiency after two doses. Third dose induced an increased and sustained humoral response in the majority of patients. However, patients within 1 year after allo-SCT remained at higher infection risk and may be candidate for prophylaxis with anti-SARS-CoV-2 monoclonal antibodies.

Risk Factors and Outcomes of Infections by Multidrug-Resistant Gram-Negative Bacteria in Patients Undergoing Hematopoietic Stem Cell Transplantation.

The objective of this study was to determine risk factors and outcomes of infections by multidrug-resistant gram-negative (MDR GN) bacteria in 241 recipients of hematopoietic stem cell transplantation (HSCT). The cumulative incidence of infections was 10.5% (95% CI, 12.0% to 25.8%), with 57% of infections occurring during the period of severe neutropenia (neutrophil count < .1 × 106/L). In multivariate analysis, allogeneic transplant and colonization with MDR GN bacteria at admission to the transplant unit were significantly associated with an increased risk of infection. Although we observed neither transplant-related mortality (TRM) nor deaths due to infections by MDR GN bacteria after autologous transplant, in the allogeneic setting a significant difference was reported in terms of overall survival (OS) and TRM between patients who developed infections and those who did not (1-year OS, 39% versus 68%; 1-year TRM, 42% versus 19%). In multivariate analysis, refractory disease and development of grades III to IV graft-versus-host disease (GVHD) were factors that affected both TRM and OS, whereas occurrence of infections by MDR GN pathogens significantly reduced OS. We conclude that eligibility to allogeneic HSCT in MDR GN bacteria carriers should be carefully evaluated together with all other factors that independently influence outcome (disease status, donor, and GVHD risk).

ABCG2, Cytogenetics, and Age Predict Relapse after Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia in Complete Remission.

Recent studies have shown that ABGG2 protein overexpression in acute myeloid leukemia (AML) may be associated with poor response to therapy and increased relapse risk. Few data are available in patients with AML undergoing allogeneic stem cell transplantation (SCT), particularly when in complete remission (CR). We analyzed 105 patients with AML who underwent allogeneic SCT in CR evaluating the role of ABCG2 and other pretransplantation features on subsequent transplantation outcomes. Factors negatively associated with leukemia-free survival (LFS) were unfavorable cytogenetics (3-year LFS 48% versus 80%, P = .0035) and ABCG2 positivity (65% versus 80%, P = .045). Three-year cumulative incidence of relapse (CIR) in the whole population was 20%; a higher incidence of relapse was associated with adverse cytogenetics (41% versus 16%, P = .018), ABCG2 overexpression (29% versus 15%, P = .04), and, marginally, age > 50 years (30% versus 14%, P = .06). We grouped patients according to the combination of these 3 risk factors: no patient relapsed within 3 years from SCT in the group without risk factors, whereas the 3-year CIR was 12% (95% confidence interval [CI], 2% to 25%) in the group with 1 risk factor and 47% (95% CI, 31% to 70%) in patients with 2 or 3 risk factors (P = .00005). In conclusion, allogeneic SCT does not seem to abrogate the negative prognosis associated with ABCG2 overexpression at diagnosis, specifically in terms of a higher relapse risk. ABCG2, age, and cytogenetics can predict AML relapse after SCT in patients who undergo transplantation while in CR.

Donor compatibility and performance status affect outcome of allogeneic haematopoietic stem cell transplant in patients with relapsed or refractory acute myeloid leukaemia.

We retrospectively analysed 78 patients with relapsed (n = 38), primary refractory (n = 34) or untreated (n = 6) acute myeloid leukaemia (AML) who underwent allogeneic HSCT at our Institution between 2002 and 2011, to verify outcome and to identify factors that can affect long-term outcome. Myeloablative conditioning regimens were used in 48 patients (24 siblings, 24 matched unrelated donor (MUD)), while 30 patients (18 siblings, 12 MUD) received reduced-intensity conditioning. Acute graft versus host disease (GVHD) developed in 37 (47 %) patients, while chronic GVHD occurred in 19 of the 65 evaluable patients (29 %). With a median follow-up time of 5 years, 13 of 78 patients (17 %) are alive and in complete remission (CR), while 64 have died. Cause of death was disease recurrence in 37 patients (58 %), infection in ten patients (16 %) and GVHD in six (9 %). One-year non-relapse mortality was 35 %. In multivariate analysis, performance status ≥80 % WHO and a full-matched donor were associated with a better outcome: these two variables allowed for risk stratification, identifying three groups with significantly different survival after transplant (P = 0.0001). Considering post-transplant variables, only CR at recovery and development of cGVHD were correlated with a longer survival. Our data confirm the capacity of allogeneic transplant to prolong survival in a significant proportion of extremely high-risk AML patients.

Impact of Cryopreservation of Peripheral Blood Stem Cells (PBSC) in Transplantation from Matched Unrelated Donor (MUD).

Background: Cryopreservation of PBSC for allogenic hematopoietic stem cell transplantation (allo-HSCT) was implemented due to the current Coronavirus 2019 pandemic. The impact of match unrelated donor (MUD) graft freezing on the outcome of allo-HSCT in terms of hematological recovery, graft versus host disease (GVHD), and survival are still controversial. Methods: In this study, we compared graft composition, clinical characteristics, and outcome of 31 allo-HSCT from MUD cryopreserved PBSC (Cryo Group) with 23 matched-pair allo-HSCT from fresh MUD PBSC (Fresh Group) performed in our center between January 2020 and July 2021. Results: No significant differences were recognized in clinical characteristics of patients, donors, and transplants between the Cryo and Fresh groups except for a better prognostic comorbidity index (HCT-CI) of the Cryo group. In the Cryo Group, the median time from apheresis to cryopreservation was 46.0 h (range 23.8−53.5), while the median time from cells collection and reinfusion was 13.9 days (range 5.8−28.1). In the Fresh Group, median time from apheresis to reinfusion was 35.6 h (range 21.4−51.2). The number of viable (7-AAD negative) CD34+ cells per kg patient infused was significantly lower in the Cryo Group (5.2 ± 1.9 × 106/kg vs. 7.0 ± 1.3 × 106/kg; p < 0.001). Indeed, there was a 36% (11−70) median loss of viable CD34+/kg cells after freezing. All patients engrafted: median time to neutrophil engraftment (>0.5 × 109/L) was 13.5 days (range 12−15) for Cryo Group and 14 days (range 13−16) days for Fresh Group (p = 0.522), while the median time to platelet engraftment (>20 × 109/L) was, respectively, 14 (range 12−18) and 15 (range 12−17) days (p = 0.904). The incidence of grade ≥ 2 acute GVHD was similar in the two groups (56.5% Cryo Group vs. 60.0% Fresh Group; p = 0.832) and no differences in terms of OS (p = 0.090), PFS (p = 0.200) and TRM (p = 0.970) were observed between the Cryo and Fresh groups. Conclusions: In our series, no differences between the Cryo and Fresh groups were found in engraftment, grade ≥ 2 acute GVHD incidence, OS, PFS, and TRM despite a lower CD34+ infused dose in the Cryo Group. Frozen PBSCs could be considered a safe option also for allo-HSCT from MUD but a higher amount of PBSC should be collected to warrant an adequate viable CD34+ post-thawing.

Allelic HLA Matching and Pair Origin Are Favorable Prognostic Factors for Unrelated Hematopoietic Stem Cell Transplantation in Neoplastic Hematologic Diseases: An Italian Analysis by the Gruppo Italiano Trapianto di Cellule Staminali e Terapie Cellulari, Italian Bone Marrow Donor Registry, and Associazione Italiana di Immunogenetica e Biologia dei Trapianti.

HLA molecules are important for immunoreactivity in allogeneic hematopoietic stem cell transplantation (HSCT). The Gruppo Italiano Trapianto di Cellule Staminali e Terapie Cellulari, Italian Bone Marrow Donor Registry, and Associazione Italiana di Immunogenetica e Biologia dei Trapianti promoted a retrospective observational study to evaluate HLA matching and the impact of allelic HLA mismatching and non-HLA factors on unrelated Italian HSCT outcomes. From 2012 to 2015, 1788 patients were enrolled in the study. The average donor age was 29 years and the average recipient age was 49 years. As a conditioning regimen, 71% of the patients received myeloablative conditioning. For GVHD prophylaxis, 76% received either antithymocyte or anti-T lymphocyte globulin, cyclosporine A, and methotrexate. Peripheral blood was the stem cell source in 80%. The median duration of follow-up was 53 months. Regarding HLA matching, 50% of donor-recipient pairs were 10/10 matched, 38% had 1 mismatch, and 12% had 2 or more mismatches. A total of 302 pairs shared Italian origin. Four-year overall survival (OS), progression-free survival, GVHD-free relapse-free survival, and relapse rates were 49%, 40%, 22%, and 34%, respectively. The 4-year NRM was 27%, and the 100-day cumulative incidence of grade ≥II acute GVHD (aGVHD) was 26%. In multivariate analysis, 9/10 and ≤8/10 HLA allele-matched pairs were associated with worse OS (P = .04 and .007, respectively), NRM (P = .007 and P < .0001, respectively), and grade III-IV aGVHD (P = .0001 and .01, respectively). Moreover, the incidences of grade II-IV aGVHD (P = .001) and chronic GVHD (P = .002) were significantly lower in Italian pairs. In conclusion, 10/10 HLA matching is a favorable prognostic factor for unrelated HSCT outcome in the Italian population. Moreover, the presence of 2 HLA-mismatched loci was associated with a higher NRM (P < .0001) and grade II-IV aGVHD (P = .006) and a poorer OS (P = .001) compared with 1 HLA-mismatched locus in early or intermediate disease phases. Finally, we found that Italian donor and recipient origin is a favorable prognostic factor for GVHD occurrence.

Risk Factors and Outcome of C. difficile Infection after Hematopoietic Stem Cell Transplantation.

Patients who undergo hematopoietic stem cell transplants (HSCT) are at major risk of C. difficile (CD) infection (CDI), the most common cause of nosocomial diarrhea. We conducted a retrospective study, which enrolled 481 patients who underwent autologous (220) or allogeneic HSCT (261) in a 5-year period, with the aim of identifying the incidence, risk factors and outcome of CDI between the start of conditioning and 100 days after HSCT. The overall cumulative incidence of CDI based upon clinical evidence was 5.4% (95% CI, 3.7% to 7.8%), without any significant difference between the two types of procedures. The median time between HSCT and CDI diagnosis was 12 days. Out of 26 patients, 19 (73%) with clinical and symptomatic evidence of CDI were positive also for enzymatic or molecular detection of toxigenic CD; in particular, in 5 out of 26 patients (19%) CD binary toxin was also detected. CDI diagnoses significantly increased in the period 2018-2019, since the introduction in the microbiology lab unit of the two-step diagnostic test based on GDH immunoenzymatic detection and toxin B/binary toxin/027 ribotype detection by real-time PCR. Via multivariate analysis, abdominal surgery within 10 years before HSCT (p = 0.002), antibiotic therapy within two months before HSCT (p = 0.000), HCV infection (p = 0.023) and occurrence of bacterial or fungal infections up to 100 days after HSCT (p = 0.003) were significantly associated with a higher risk of CDI development. The 26 patients were treated with first-line vancomycin (24) or fidaxomicine (2) and only 2 patients needed a second-line treatment, due to the persistence of stool positivity. No significant relationship was identified between CDI and the development of acute graft versus host disease (GVHD) after allogeneic HSCT. At a median follow-up of 25 months (range 1-65), the cumulative incidence of transplant related mortality (TRM) was 16.6% (95% CI 11.7% to 22.4%) and the 3-year overall survival (OS) was 67.0% (95% CI 61.9% to 71.6%). The development of CDI had no significant impact on TRM and OS, which were significantly impaired in the multivariate analysis by gastrointestinal and urogenital comorbidities, severe GVHD, previous infections or hospitalization within two months before HSCT, active disease at transplant and occurrence of infections after HSCT. We conclude that 20% of all episodes of diarrhea occurring up to 100 days after HSCT were related to toxigenic CD infection. Patients with a history of previous abdominal surgery or HCV infection, or those who had received broad spectrum parenteral antibacterial therapy were at major risk for CDI development. CDIs were successfully treated with vancomycin or fidaxomicin after auto-HSCT as well as after allo-HSCT.

The development of autoantibodies after allogeneic stem cell transplantation is related with chronic graft-vs-host disease and immune recovery.

OBJECTIVE: Chronic graft-vs-host disease (GVHD) has certain similarities with autoimmune diseases and is associated with the development of various autoantibodies in some patients. In this study, we analyzed the occurrence of autoantibodies in 63 patients surviving longer than 3 months after an allogeneic haematopoietic stem cell transplantation (HSCT), with the aim of detecting a possible association between occurrence of autoantibodies and development of chronic GVHD and immune recovery after HSCT. PATIENTS AND METHODS: The patients were screened every 3 months for the occurrence of the following autoantibodies: anti-nuclear (ANA), anti-mitochondrial (AMA), anti-smooth muscle (ASMA), anti-cardiolipin (ACLA), anti-liver-kidney microsomal (LKM), anti-DNA, anti-neutrophil cytoplasmatic (ANCA), and anti-thyroid antibodies. Peripheral blood immunophenotyping with anti-CD3, CD4, CD8, CD19, CD20, CD16, and CD56 antibodies was evaluated at the same intervals. RESULTS: Autoantibodies were not found in 18 patients (29%), at least in one screening in 29 patients (46%), and in all screenings in 16 patients (25%). ANA were found in 41 patients (65%), AMA in 4 (6%), ASMA in 4 (6%), ANCA in 7 (11%), ACLA in 1 (2%), anti-thyroid antibodies in 3 (5%), and anti-DNA in 2 (3%). More than one antibody occurred in 16/63 (25%) positive patients. ANA was significantly more frequent in patients with chronic GVHD and, among these, in those with the extensive form. The nucleolar pattern of immunofluorescence of ANA but not its titer was correlated with the extension of chronic GVHD. Patients who developed autoantibodies had higher CD20(+) cell blood counts than negative patients in the third month (p=0.006), ninth month (p=0.061), and twelfth month (p=0.043). CONCLUSION: We conclude that patients with chronic GVHD, particularly those with an extensive involvement, were likely to develop autoantibodies and have a faster B-cell recovery, suggesting a role of B cells in the pathogenesis of chronic GVHD.

Predictive value of pretransplantation molecular minimal residual disease assessment by WT1 gene expression in FLT3-positive acute myeloid leukemia.

The FMS-like tyrosine kinase 3 (FLT3) mutation in acute myeloid leukemia (AML) is a negative prognostic factor and, in these cases, allogeneic stem cell transplantation (allo-SCT) can represent an important therapeutic option, especially if performed in complete remission (CR). However, it is increasingly clear that not all cytological CRs (cCRs) are the same and that minimal residual disease (MRD) before allo-SCT could have an impact on AML outcome. Unfortunately, FLT3, due its instability of expression, is still not considered a good molecular MRD marker. We analyzed the outcome of allo-SCT in a population of FLT3-positive AML patients according to molecular MRD at the pretransplantation workup, assessed by the quantitative expression evaluation of the panleukemic marker Wilms' tumor (WT1) gene. Sixty-two consecutive AML FLT3-positive patients received allo-SCT between 2005 and 2016 in our center. The median age at transplantation was 55 years. The quantitative analysis of the WT1 gene expression (bone marrow samples) was available in 54 out of 62 (87%) cases, both at diagnosis (100% overexpressing WT1 with a mean of 9747 ± 8064 copies) and before allo-SCT (33 WT1-negative and 21 WT1-positive cases at the pretransplantation workup). Of these cases, 33/54 (61%) were both in cCR and molecular remission (WT1-negative) at the time of transplantation, 13/54 (24%) were in cCR but not in molecular remission (WT1-positive), and 8/54 (15%) showed a cytological evidence of disease (relapsed or refractory). Both post-allo-SCT overall survival (OS) and disease-free survival (DFS) were significantly better in patients who were WT1-negative (WT1 <250 copies) at the time of transplantation compared with those who were WT1-positive (WT1 >250 copies), with a median OS and DFS not reached in the WT1-negative group and 10.2 and 5.5 months, respectively, in the WT1-positive group (OS log-rank p = 0.0005; hazard ratio [HR] = 3.7, 95% confidence interval [95% CI] = 1.5-9; DFS log-rank p = 0.0001; HR = 4.38, 95% CI = 1.9-10). Patients with cCR who were WT1-positive had the same negative outcome as those with a cytological evidence of disease. The relapse rate after allo-SCT was 9% (3/33) in pre-allo-SCT WT1-negative cases and 54% (7/13) in WT1-positive cases (p = 0.002). At multivariate analysis, WT1 negativity before allo-SCT and grade <2 acute graft versus host disease were the only independent prognostic factors for improved OS and DFS. These data show that pre-allo-SCT molecular MRD evaluation through WT1 expression is a powerful predictor of posttransplantation outcomes (OS, DFS, relapse rate). Patients with both cCR and a WT1-negative marker before allo-SCT have a very good outcome with very low relapse rate; conversely, patients with positive molecular MRD and refractory/relapsed patients have a negative outcome. The WT1 MRD stratification in FLT3-positive AML is a valuable tool with which to identify patients who are at high risk of relapse and that could be considered from post-allo-SCT prophylaxis with FLT3 inhibitors or other strategies (donor lymphocyte infusion, tapering of immunosuppression, azacitidine).

Sclerodermatous chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation: incidence, predictors and outcome.

Scleroderma may be one of the most severe forms of chronic graft-versus-host disease (GVHD). We retrospectively evaluated its incidence, predictor variables and outcome in 133 patients who survived at least 4 months after allogeneic hematopoietic stem cell transplantation. The 5-year cumulative incidence was 15.5% in patients with chronic GVHD. The generalized form had a progressive course despite immunosuppressive therapy. Eosinophilia, autoimmune markers, and previous skin involvement by chronic GVHD with disorders of pigmentation were significantly associated with an increased probability of developing scleroderma.

Effect on survival of the development of late-onset non-infectious pulmonary complications after stem cell transplantation.

We evaluated the incidence, risk factors, and clinical outcome of late-onset non-infectious pulmonary complications (LONIPC) in 599 patients who underwent hematopoietic allogeneic stem cell transplantation (HSCT). The 2-year cumulative incidence of LONIPC was 10% among the 438 patients surviving more than 3 months after HSCT. Transplants from an unrelated donor and occurrence of extensive chronic graft-versus-host disease were the variables significantly associated with the development of LONIPC. The 5-year overall survival was significantly worse among patients with LONIPC than among those without (34% vs 65%, p=0.009). Causes of death were respiratory failure and infections. The relapse rate was similar in the two groups.

The use of G-CSF during first line chemotherapy adversely affects the yield of PBSC mobilization in non-Hodgkin's lymphoma patients.

Regardless the mobilization procedure used there is a great variability from patient to patient in the yield of CD34 collections for autologous transplantation. We analyzed retrospectively our non-Hodgkin's lymphoma survey of 60 patients harvested with G-CSF alone after a unique first line chemotherapy; 67% of patients harvested a sufficient number of CD34+ cells during the first attempt of mobilization. The charachteristics of leukaphereses procedures were the same for all the patients. Sex, age, months from the end of chemo- or radio-therapy did not have a significance in influencing mobilization capability, while requirement of G-CSF during chemotherapy was statistically different from failures to successes: 16/20 (80%) of patients failing to reach the target of 2x10(6)/kg CD34+ cells had required G-CSF support during previous chemotherapy versus 18/40 (45%) in the successful group (p 0,005). Our observation supports the hypotesis that individual biological charachteristics of each patient are the most important factors in affecting mobilization capability, deserving further investigation: mobilization schedules tailored on a given patient would minimize the rate of failures, avoiding a second attempt of collection that implies additional economic expenses and negative consequences on the maintenance of dose intensity.

Autologous stem cell transplantation for Hodgkin's lymphoma: results and prognostic factors in 51 high-risk patients.

Autologous stem cell transplantation (ASCT) is largely employed in primary resistant or recurrent Hodgkin's Lymphoma (HL), while its role early in the course of the disease is still controversial. Our purpose was to analyse the results of 51 high-risk HL patients autografted at our Institution and the role of possible prognostic risk factors for the outcome. Twelve (23.5%) patients were in complete remission at transplant and were transplanted as having an high risk disease; 20 (39.5%) patients were in partial response and 19 (37.0%) were transplanted as primary induction failure. At a median time of 38 (6-111) months from ASCT, 36 (70.5%) patients are alive in complete remission, 8 (15.5%) patients are alive with disease and 7 (14.0%) died for progression. Thirty out of 32 (94.0%) patients transplanted with responsive disease (either complete or partial response) are alive without disease. Six out of 19 (32.0%) patients transplanted with resistant disease are alive in complete remission. The overall survival of the entire population is 77.0% at 60 (14-151) months from diagnosis. Disease free survival of the 22 patients that achieved a complete remission after ASCT (16 in partial response and 6 with resistant disease) is 100%. In our experience, more than 90% of patients transplanted with responsive but high risk disease, seem achieving and maintaining a durable complete remission, and more than 30.0% of patients submitted to ASCT with refractory disease can be potentially rescued by transplant.