Mechanical strain induces ex vivo expansion of periosteum.

Segmental bone defects present complex clinical challenges. Nonunion, malunion, and infection are common sequalae of autogenous bone grafts, allografts, and synthetic bone implants due to poor incorporation with the patient's bone. The current project explores the osteogenic properties of periosteum to facilitate graft incorporation. As tissue area is a natural limitation of autografting, mechanical strain was implemented to expand the periosteum. Freshly harvested, porcine periosteum was strained at 5 and 10% per day for 10 days with non-strained and free-floating samples serving as controls. Total tissue size, viability and histologic examination revealed that strain increased area to a maximum of 1.6-fold in the 10% daily strain. No change in tissue anatomy or viability via MTT or Ki67 staining and quantification was observed among groups. The osteogenic potential of the mechanical expanded periosteum was then examined in vivo. Human cancellous allografts were wrapped with 10% per day strained, fresh, free-floating, or no porcine periosteum and implanted subcutaneously into female, athymic mice. Tissue was collected at 8- and 16-weeks. Gene expression analysis revealed a significant increase in alkaline phosphatase and osteocalcin in the fresh periosteum group at 8-weeks post implantation compared to all other groups. Values among all groups were similar at week 16. Additionally, histological assessment with H&E and Masson-Goldner Trichrome staining showed that all periosteal groups outperformed the non-periosteal allograft, with fresh periosteum demonstrating the highest levels of new tissue mineralization at the periosteum-bone interface. Overall, mechanical expansion of the periosteum can provide increased area for segmental healing via autograft strategies, though further studies are needed to explore culture methodology to optimize osteogenic potential.

Prolonged SARS-CoV-2 infection during autologous hematopoietic stem cell transplantation from Hodgkin's lymphoma: a case report.

Autologous hematopoietic stem cell transplantation (HSCT) for relapsed Hodgkin's lymphoma increases the risk of infection by using intensive chemotherapy. This risk is obviously ongoing given the increased virulence of severe COVID-19. We report a case of a young man with Hodgkin's lymphoma who received conditioning chemotherapy followed by autologous HSCT and tested positive for SARS-CoV-2 by polymerase chain reaction (PCR) during the early phase of aplasia with persistence of COVID-19 beyond 30 days with favorable follow-up and clinical improvement on treatment. For this type of patient with hematologic malignancy, viral infection can be fatal and strict medical precautions with isolation rules must be maintained, especially for SARS-CoV-2.

SARS-CoV-2-reactive antibody waning, booster effect and breakthrough SARS-CoV-2 infection in hematopoietic stem cell transplant and cell therapy recipients at one year after vaccination.

The kinetics of SARS-CoV-2 reactive IgG antibodies after full vaccination and booster in allogeneic and autologous stem cell transplantation (allo-HSCT, ASCT) and chimeric antigen receptor T-cell therapy (CAR-T) are of utmost importance for estimating risk of infection. A prospective multicenter registry-based cohort study, conducted from December 2020 to July 2022 was used to analyze antibody waning over time, booster effect and the relationship of antibody response and breakthrough infection in 572 recipients (429 allo-HSCT, 121 ASCT and 22 CAR-T cell therapy). A significant decline in antibody titers was observed at 3 and 6 months after full vaccination in recipients without pre-vaccine SARS-CoV-2 infection, whereas recipients infected prior to vaccination showed higher and stable antibody titers over time. In poor responders, a booster dose was able to increase antibody titers in 83% of allo-HSCT and 58% of ASCT recipients but not in CART-T cell recipients [0%] (p < 0.01). One-year cumulative incidence of breakthrough infection was 15%, similar among cell therapy procedures. Immunosuppressive drugs at the time of vaccination [hazard ratio (HR) 1.81, p = 0.0028] and reduced intensity conditioning (HR 0.49, p = 0.011) were identified as the only conditions associated with different risk of breakthrough infection in allo-HSCT recipients. Antibody titers were associated with breakthrough infection and disease severity. No death was observed among the 72 breakthrough infections. Antibody level decay after the first two vaccine doses was common except in recipients with pre-vaccination SARS-CoV-2 infection. Poorly responding allo-HSCT recipients showed a response advantage with the booster as compared to ASCT and, especially, the null response found in CAR-T cell recipients. Antibody titers were positively correlated with the risk of breakthrough SARS-CoV-2 infection which was mainly driven by the immunosuppression status.

Successful Autologous Bone Marrow Transplantation in Active COVID-19 Patients: Case Report.

BACKGROUND: Patients with hematologic malignancies are considered at high risk for COVID-19 infection either from the disease or the treatment. Hematopoietic stem cell transplantation, one of the approved therapies for hematologic malignancies, was performed worldwide during the COVID-19 era with some regulations, such as COVID-19 testing, before proceeding with transplantation or cellular therapy. To the authors' knowledge, none have reported the result of autologous hematopoietic stem cell transplantation in an active COVID-19 patient. CASE PRESENTATION: We describe a successful clinical course of autologous bone marrow transplantation for 2 lymphoma patients who tested positive for COVID-19. A thorough discussion was conducted between multidisciplinary hemato-oncology, intensive care, and infectious diseases teams. The decision was to proceed toward bone marrow transplantation with some modifications in the transplantation protocol and close patient monitoring. CONCLUSION: Our cases lend credence that successful autologous bone marrow transplantation is possible among active COVID-19 patients. The obstacles we faced could be overcome with collaboration between a highly qualified multidisciplinary team. Despite the potential complications, the benefits of bone marrow transplantation among patients with a high risk of relapse and who are still COVID-19-positive outweigh the risks. However, further studies are still recommended to support our inference.

Delayed diagnosis resulting in increased disease burden in multiple myeloma: the legacy of the COVID-19 pandemic.

The COVID-19 pandemic has had global healthcare impacts, including high mortality from SARS-CoV-2 infection in cancer patients; individuals with multiple myeloma (MM) are especially susceptible to poor outcomes. However, even for MM patients who avoided severe infection, the ramifications of the pandemic have been considerable. The consequences of necessary socio-geographical behavior adaptation, including prolonged shielding and interruptions in delivery of non-pandemic medical services are yet to be fully understood. Using a real-world dataset of 323 consecutive newly diagnosed MM patients in England, we investigated the impact of the COVID-19 pandemic on routes to myeloma diagnosis, disease stage at presentation and relevant clinical outcomes. We demonstrate increasing MM presentations via emergency services and increased rates of bony and extra-medullary disease. Differences were seen in choice of induction therapy and the proportion of eligible patients undertaking autologous stem cell transplantation. Whilst survival was statistically inferior for emergency presentations, significant survival differences have yet to be demonstrated for the entire cohort diagnosed during the pandemic, making extended follow-up critical in this group. This dataset highlights wide-ranging issues facing MM patients consequent of the COVID-19 pandemic, with full impacts for clinicians and policy-makers yet to be elucidated.

Complications Associated with Peripherally Inserted Central Catheters (PICC) in People Undergoing Autologous Hematopoietic Stem Cell Transplantation (HSCT) in Home Hospitalization.

INTRODUCTION: The SARS-CoV-2 pandemic generated the need to keep immunosuppressed patients away from hospital institutions for as long as possible. This in turn stimulated the implementation of a home hospitalization model for autologous hematopoietic stem-cell transplantation (HSCT). PURPOSE: To analyze whether there are significant differences in post-transplantation complications related to catheters observed in patients treated in the home-transplant care modality compared to patients treated in the hospital. METHODOLOGY: Observational, analytical, longitudinal, and retrospective study of cases and controls. A convenience sample was chosen, in which the cases comprised 20 patients included in the home HSCT care model. For each patient, it was considered suitable to propose two controls among those who received autologous transplantation in the last five years with a baseline demographic and pathological profile similar to the case for whom they were control. RESULTS: The home patients achieved an average of 22.4 ± 2.6 days of evolution with an average of 16.4 ± 2.08 days post-transplant, compared to the hospital process with an average of 21.21 ± 4.18 days of evolution and 15.51 ± 3.96 days post-transplant (evolution days p = 0.022; post-transplant days p = 0.002). A higher percentage of use of parenteral nutrition (p = 0.036) and transfusions (p = 0.003) was observed during the post-transplant phase in the hospital. The rest of the therapeutic measures did not show significant differences. When analyzing the frequency of adverse effects in the post-transplant phase, a significant increase in neutropenic fever (OR = 8.55) and positive blood cultures (OR = 6.65) was observed in hospital patients. Any other significant differences in other variables related to PICC were found (presence and days of neutropenic fever, catheter infection, complications, pathogens, admission to the ICU, or death). Concerning local complications (pain, DVT, Medical adhesive-related Skin Injury, and erythema), there was more erythema in the hospital (p = 0.056). CONCLUSIONS: The results obtained indicate that regarding the appearance of complications associated with PICCs in home hospitalization HSCT patients, there are no significant differences compared to hospitalization, so that home care can be a safe context for people with these lines.

[Vaccination before and after autologous hematopoietic cell transplantation for autoimmune diseases: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (MATHEC-SFGM-TC)]. / Vaccinations avant et après greffe de cellules hématopoïétiques autologues chez les patients atteints de maladies auto-immunes : propositions du groupe Maladies Auto-immunes et Thérapie Cellulaire de la SFGM-TC.

The Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) organized the 12th workshop on hematopoietic stem cell transplantation clinical practices harmonization procedures on September 2021 in Lille, France. In the absence of specific national or international recommendation, the French working group for autologous stem Cell transplantation in Auto-immune Diseases (MATHEC) proposed guidances for vaccinations of patients undergoing autologous hematopoietic stem cell transplantation for autoimmune disease, including in the context of SARS-Cov-2 pandemic.

Specific Antibody and the T-Cell Response Elicited by BNT162b2 Boosting After Two ChAdOx1 nCoV-19 in Common Variable Immunodeficiency.

Common variable immunodeficiency (CVID) patients have markedly decreased immune response to vaccinations. In this study we evaluated humoral and T cell-mediated responses against severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2) with additional flow cytometric changes in CVID patients receiving booster vaccination with BNT162b2 after two ChAdOx1 nCoV-19. The BNT162b2 vaccine raised the anti-spike protein S immunoglobulin G over the cut-off value from 70% to 83% in CVID, anti-neutralizing antibody had been raised over a cut-off value from 70% to 80% but levels after boosting were significantly less in both tests than in healthy controls (*p=0.02; **p=0.009 respectively). Anti-SARS-CoV-2 immunoglobulin A became less positive in CVID after boosting, but the difference was not significant. The cumulative interferon-γ positive T cell response by ELISpot was over the cut-off value in 53% of the tested individuals and raised to 83% after boosting. This and flow cytometric control of cumulative CD4+ and CD8+ virus-specific T cell absolute counts in CVID were also statistically not different from healthy individuals after boosting. Additional flow cytometric measures for CD45+ lymphocytes, CD3+, and CD19+ cells have not shown significant differences from controls except for lower CD4+T cell counts at both time points (**p=0.003; **p=0.002), in parallel CD4+ virus-specific T-cell ratio was significantly lower in CVID patients at the first time point (*p: 0.03). After boosting, in more than 33% of both CVID patients and also in their healthy controls we detected a decrease in absolute CD45+, CD3+, CD3+CD4+, and CD3+CD8+, CD19+, and CD16+56+ cell counts. CD16+CD56+ cell counts were significantly lower compared to controls before and after boosting (*p=0.02, *p=0.02). CVID patients receiving immunosuppressive therapy throughout the previous year or autologous stem cell transplantation two years before vaccination had worse responses in anti-spike, anti-neutralizing antibody, CD3+CD4+T, CD19+ B, and natural killer cell counts than the whole CVID group. Vaccinations had few side effects. Based on these data, CVID patients receiving booster vaccination with BNT162b2 after two ChadOx1 can effectively elevate the levels of protection against COVID-19 infection, but the duration of the immune response together with COVID-19 morbidity data needs further investigation among these patients.

[Multiple myeloma: response to treatment and survival of patients according to the interim analysis of the Russian observational, retrospective-prospective, multicenter cohort study (MULTISPECT)].

AIM: The primary objective of the interim analysis of the MULTISPECT study was to evaluate the short-term efficacy of the treatment and long-term outcomes in cohorts of primary and pretreated patients with multiple myeloma (MM) receiving treatment in actual clinical practice in various regions of the Russian Federation. Secondary objectives were a description of the main characteristics of patients; analysis of the most commonly used therapy regimens of the 1st and later lines and the sequence of their changes; evaluation of the response to therapy. Additional objectives included evaluation of the effect of the new COVID-19 coronavirus infection on the course of MM in patients. MATERIALS AND METHODS: The study is an observational retrospective-prospective multicenter cohort study. For its implementation, a structured database of patients with MM was used, provided by hematologists of the centers affiliated for the study. RESULTS: The study included 1,294 patients (cohort 1 806, cohort 2 488). In both cohorts, patients aged 6069 years were in the majority. 3 lines of therapy (L1, L2, L3) were used for cohort 1; in cohort 2, the 4th line of therapy was also used in 2 patients. The therapy regimens were analyzed for 290 (22.41%) of all patients in the study. Responses to therapy were analyzed for 214 patients of cohort 1 and 109 patients of cohort 2. Autologous and allogeneic hematopoietic stem cell transplantations were carried out for a limited proportion of patients in both cohorts. At the end of the study and upon presentation of its results, the status of patients was the following: 96% of patients in cohort 1 and 89% in cohort 2 were alive. The therapy regimens in both cohorts were characterized by variability. The most commonly used regimens in each of the lines of therapy have been identified. The most used therapy regimen in patients with MM of both cohorts was the VCD-regime. Rd-regime in cohort 1 and RD-regime in cohort 2 were the second most frequent used regimens. In patients of both cohorts, the therapy regimens including Bortezomib were most often used. CONCLUSION: The variety of therapy regimens used to treat MM in actual clinical practice may be due to the factors of availability of new medicines and updated recommendations for the treatment of the disease. Further, in the context of this study, a more detailed analysis of the efficacy of certain therapy regimens in the 1st and later lines on progression free survival and overall survival of MM patients should be carried out.

Antibody response to COVID-19 vaccine in 130 recipients of hematopoietic stem cell transplantation.

We evaluated anti-spike protein antibody (anti-S) production in 130 hematopoietic stem cell transplant (HSCT) recipients who received the coronavirus disease-2019 vaccine. Sixty-five received allo-HSCT and 65 received auto-HSCT. Disease-specific treatments were being administered to 43.1% of allo-HSCT and 69.2% of auto-HSCT patients. Seropositivity was observed in 87.7% of allo-HSCT and 89.2% in auto-HSCT patients. Anti-S antibody production was significantly impaired in auto-HSCT patients compared with controls (178U/mL [0.4-4990.0] vs. 669 U/mL [40.3-4377.0], p < 0.001), but not in allo-HSCT patients (900 U/mL [0.4-12,893.0] vs. 860 U/mL [40.3-8988.0], P = 0.659). Clinically relevant anti-S antibody levels (> 264 U/mL) were achieved in 59.2% of patients (76.9% in allo-HSCT and 41.5% in auto-HSCT). The main factors influencing the protective level of the antibody response were the CD19 + cell count and serum immunoglobulin G levels, and these were significant in both allo-HSCT and auto-HSCT patients. Other factors included time since HSCT, complete remission status, use of immunosuppressive drugs, and levels of lymphocyte subsets including CD4, CD8 and CD56 positive cells, but these were only significant in allo-HSCT patients. Allo-HSCT patients had a relatively favorable antibody response, while auto-HSCT patients had poorer results.

The impact of COVID-19 on autologous stem cell transplantation in multiple myeloma: A single-centre, qualitative evaluation study.

Autologous stem cell transplantation (ASCT) is standard of care in biologically fit, newly diagnosed multiple myeloma (MM) patients, offering better therapeutic outcomes and improved quality of life (QoL). However, with the UK's 1st national lockdown on 23/03/2020, several guidelines recommended deferring ASCT due to risks of infection, with resource limitations forcing some units to suspend ASCT entirely. Such changes to patients' treatment plans inevitably altered their lived experience during these uncertain times with expected impact on QoL. We conducted a qualitative study using semi-structured interviews to gain insight into MM patients' understanding of their disease, initial therapy and ASCT, and their response to therapy changes. A clinical snapshot of how COVID-19 affected the MM ASCT service in a single UK institution is also provided, including changes to chemotherapy treatment plans, timing, and prioritisation of ASCT. Framework analysis identified 6 overarching themes: (1) beliefs about ASCT, (2) perceptions of information provided about MM and ASCT, (3) high levels of fear and anxiety due to COVID-19, (4) feelings about ASCT disruption or delay due to COVID-19, (5) perceptions of care, and (6) importance of social support. Example subthemes were beliefs that ASCT would provide a long-remission/best chance of normality including freedom from chemotherapy and associated side-effects, disappointment, and devastation at COVID-related treatment delays (despite high anxiety about infection) and exceptionally high levels of trust in the transplant team. Such insights will help us adjust our service and counselling approaches to be more in tune with patients' priorities and expectations.

Safety and efficacy of a dose-dense short-term therapy in patients with MYC-translocated aggressive lymphoma.

Patients with aggressive B-cell lymphoma and MYC rearrangement at fluorescence in situ hybridization exhibit poor outcome after R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone). In the last decade, 68 patients with Burkitt lymphoma ([BL] n = 46) or high-grade B-cell lymphoma ([HGBCL] single, double, or triple hit; n = 22) were treated with a dose-dense, short-term therapy termed "CARMEN regimen" at 5 Italian centers. Forty-six (68%) patients were HIV+. CARMEN included a 36-day induction with sequential, single weekly doses of cyclophosphamide, vincristine, rituximab, methotrexate, etoposide, and doxorubicin plus intrathecal chemotherapy, followed by high-dose-cytarabine-based consolidation. Patients who did not achieve complete remission (CR) after induction received BEAM (carmustina, etoposide, cytarabine, melfalan)-conditioned autologous stem cell transplantation (ASCT) after consolidation. Sixty-one (90%) patients completed induction, and 59 (87%) completed consolidation. Seventeen patients received ASCT. Grade 4 hematological toxicity was common but did not cause treatment discontinuation; grade 4 nonhematological toxicity was recorded in 11 (16%) patients, with grade 4 infections in 6 (9%). Six (9%) patients died of toxicity (sepsis in 4, COVID-19, acute respiratory distress syndrome). CR rate after the whole treatment was 73% (95% confidence interval [CI], 55% to 91%) for patients with HGBCL and 78% (95% CI, 66% to 90%) for patients with BL. At a median follow-up of 65 (interquartile range, 40-109) months, 48 patients remain event free, with a 5-year progression-free survival of 63% (95% CI, 58% to 68%) for HGBCL and 72% (95% CI, 71% to 73%) for BL, with a 5-year overall survival (OS) of 63% (95% CI, 58% to 68%) and 76% (95% CI, 75% to 77%), respectively. HIV seropositivity did not have a detrimental effect on outcome. This retrospective study shows that CARMEN is a safe and active regimen both in HIV-negative and -positive patients with MYC-rearranged lymphomas. Encouraging survival figures, attained with a single dose of doxorubicin and cyclophosphamide, deserve further investigation in HGBCL and other aggressive lymphomas.

Adaptation of the PERCEPT myeloma prehabilitation trial to virtual delivery: changes in response to the COVID-19 pandemic.

INTRODUCTION AND OBJECTIVE: Research activity was impacted by the novel COVID-19 pandemic, the PERCEPT myeloma trial was no exception. This pilot randomised trial delivered a face-to-face exercise intervention prior to and during autologous stem cell transplantation (ASCT) in myeloma patients, as a consequence of COVID-19 it required significant adaptions to continue. This brief communication describes how the previously published study protocol was adapted for virtual delivery. In addition, we highlight the challenge of continuing the study which was embedded within a clinical pathway also impacted by the pandemic. SUMMARY: The original trial protocol was amended and continued to recruit and deliver an exercise prehabilitation intervention virtually. Continued delivery of the intervention was deemed important to participants already enrolled within the trial and the adapted virtual version of the trial was acceptable to the research ethics committee as well as participants. Development of effective, remotely delivered rehabilitation and physical activity programmes are likely to benefit people living with myeloma. The COVID-19 pandemic provided an opportunity to explore the feasibility of a virtual programme for ASCT recipients, however, continued changes to the clinical pathway within which the study was embedded posed the greatest challenge and ultimately led to early termination of recruitment. TRIAL REGISTRATION NUMBER: ISRCTN15875290; pre-results.

Prolonged Lenalidomide Induction Does Not Significantly Impair Stem Cell Collection in Multiple Myeloma Patients Mobilized With Cyclophosphamide or Plerixafor: A Report From The Covid Era.

INTRODUCTION: Induction therapy for multiple myeloma is traditionally capped at 6 cycles of lenalidomide due to concerns that longer treatment compromises the ability to collect sufficient stem cells for autologous stem cell transplantation (ASCT). However, during the COVID-19 pandemic, many of our patients received prolonged lenalidomide induction due to concerns about proceeding to ASCT. We investigated whether prolonged induction with lenalidomide affects the efficacy of stem cell collection among patients mobilized with cyclophosphamide and/or plerixafor. PATIENTS AND METHODS: This single center, retrospective study included patients who were treated with lenalidomide induction regimens, received mobilization with cyclophosphamide or plerixafor, and underwent apheresis in preparation for ASCT. 94 patients were included, 40 of whom received prolonged induction with >6 cycles of lenalidomide containing regimen. RESULTS: Patients who received prolonged induction were more likely to require >1 day of apheresis (38% vs. 15%; OR 3.45; P = .0154), and there was a significant correlation between the duration of lenalidomide treatment and the apheresis time required to collect sufficient cells for transplant (R2 = 0.06423, P = .0148). However, there was no significant difference between patients who received prolonged induction and those who did not with respect to CD34+ stem cell yields at completion of apheresis (9.99 vs. 10.46 cells/Kg, P = .5513) or on the first day of collection (8.29 vs. 9.59 cells/Kg, P = .1788). CONCLUSION: Among patients treated with >6 cycles of lenalidomide, mobilization augmented with cyclophosphamide and/or plerixafor will likely facilitate sufficient stem cell harvest to permit ASCT.

Autologous Islet Transplantation After Total Pancreatectomy in a Patient Recovered from SARS-CoV-2: A Case Report.

BACKGROUND SARS-CoV-2 infection or COVID-19 disease has been linked to the onset of diabetes and metabolic dysregulation because it has been suggested that viral entry proteins, specifically ACE2 and TMPRSS2, are expressed in the exocrine cells and ductal epithelium of the pancreas. Because of the unknown effect this can have on islet function, there can be doubt that patients with previous SARS-CoV-2 infections are good candidates for autologous islet transplantation after total pancreatectomy (TPAIT). CASE REPORT A patient with a history of chronic pancreatitis and previous non-surgical interventions was presented as a viable candidate for TPAIT at our institution. Approximately 1 month later, the patient contracted a SARS-CoV-2 infection, resulting in a mild case of COVID-19. The infection resolved without the need for hospitalization. At the time of this occurrence, COVID-19 was primarily considered a respiratory ailment, and little was known of the potential association between metabolic dysfunction and SARS-CoV-2. Islet isolation and surgery proceeded in a textbook manner with no surgical complications. The patient was weaned off exogenous insulin within 3 months after transplantation. CONCLUSIONS Favorable outcomes after surgery included pain reduction, islet function, and improved quality of life for the patient in the first 6 months after the procedure. These successful results demonstrate that SARS-CoV-2 infection did not prevent the patient from achieving good glucose regulation after auto-islet transplantation. This outcome suggests that, at least in this instance of mild infection, there were no long-lasting negative COVID-19-associated effects on the transplanted islets that might impact islet function.

Impact of COVID-19 in hematopoietic stem cell transplant recipients: A systematic review and meta-analysis.

BACKGROUND: Hematopoietic stem cell transplant (HSCT) recipients are at increased risk of mortality and morbidity with coronavirus disease 2019 (COVID-19) due to severe immune dysfunction. METHODS: A literature search was performed on PubMed, Cochrane, and Clinical trials.gov from the date of inception to 12/08/2021. We identified 19 original studies reporting data on COVID-19 in HSCT recipients after screening 292 articles. Data were extracted following preferred reporting items for systematic reviews and meta-analysis guidelines. Quality evaluation was done using the National Institutes of Health (NIH) quality assessment tool. Inter-study variance was calculated using Der Simonian-Laird Estimator. Pooled analysis was conducted using MetaXL. A random-effects model was used to estimate the proportions with 95% confidence intervals (CI). RESULTS: Of 6711 patients in 19 studies, 2031 HSCT patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were analyzed. The median age of patients was 56.9 (range 1-81.6) years, and 63% patients were men according to 14 studies. The median time from transplant to SARS-CoV-2 infection for autologous (auto) and allogeneic (allo) HSCT patients was 23.2 (0.33-350.5) months and 16.4 (0.2-292.7) months, respectively. The median follow-up time after COVID-19 diagnosis was 28 (0-262) days. The COVID-19 mortality rate was 19% (95% CI 0.15-0.24, I2  = 76%, n = 373/2031). The pooled mortality rate was 17% (95% CI 0.12-0.24, I2  = 78%, n = 147/904) in auto-HSCT patients and 21% (95% CI 0.16-0.25, I2  = 60%, n = 231/1103) in allo-HSCT patients. CONCLUSIONS: HSCT recipients have a high risk of mortality and clinical complications due to COVID-19. There is a need for ongoing vigilance, masks, and social distancing, vaccination, and aggressive management of SARS-CoV-2 infection in HSCT recipients.