Reconstitution of the immune system after hematopoietic stem cell transplantation in humans

Hematopoietic stem cell transplantation is associated with a severe immune deficiency. As a result, the patient is at high risk of infections. Innate immunity, including epithelial barriers, monocytes, granulocytes, and NK cells recovers within weeks after transplantation. By contrast, adaptive immunity recovers much slower. B- and T-cell counts normalize during the first months after transplantation, but in particular, T-cell immunity may remain impaired for years. During the last decade, much of the underlying mechanisms have been identified. These insights may provide new therapies to accelerate recover

Allogeneic hematopoietic stem cell transplantation in Hodgkin lymphoma in Switzerland, 20 years of experience: 2001–2020

Despite the high cure rate with initial therapy, approximately 10% of Hodgkin lymphoma (HL) patients are refractory to initial treatment, and up to 30% of patients will relapse after achieving initial complete remission. Despite promising initial results of treatment by immune checkpoint inhibitors, most patients will eventually progress. We analyzed 62 adult patients with relapsed or refractory HL (rrHL) treated by allogeneic hematopoietic stem cell transplantation (allo-HSCT) in one of three University Hospitals of Switzerland (Zurich, Basel, and Geneva) between May 2001 and January 2020. The primary endpoint was overall survival (OS). Secondary endpoints were relapse-free survival (RFS), non-relapse mortality (NRM), and relapse incidence, which were assessed in univariate analysis. The median follow-up was 61 months (interquartile range 59–139). The 2- and 5-year OS was 54% (standard error (SE) ±12) and 50.2% (SE ±13.3), respectively, and the 2- and 5-year RFS was 40.7% (SE ±16.3) and 34.4% (SE ±19.0), respectively. NRM was 23.1% (SE ±2.2) and 27.4% (SE ±2.5) at 2 and 5 years, respectively. The cumulative incidence of relapse was 36.1% (SE ±5.6) at 2 years and 38.2% (SE ±6.6) at 5 years. Our analysis of allo-HSCT outcomes in the context of rrHL shows encouraging OS and RFS rates, with the mortality rate reaching plateau at 50% at 2 years after allo-HSCT. This confirms that allo-HSCT still remains as a potentially curative option for half of patients with rrHL

E119D Neuraminidase Mutation Conferring Pan-Resistance to Neuraminidase Inhibitors in an A(H1N1)pdm09 Isolate From a Stem-Cell Transplant Recipient

Background. An influenza A(H1N1)pdm09 infection was diagnosed in a hematopoietic stem cell transplant recipient during conditioning regimen. He was treated with oral oseltamivir, later combined with intravenous zanamivir. The H275Y neuraminidase (NA) mutation was first detected, and an E119D NA mutation was identified during zanamivir therapy. Methods. Recombinant wild-type (WT) E119D and E119D/H275Y A(H1N1)pdm09 NA variants were generated by reverse genetics. Susceptibility to NA inhibitors (NAIs) was evaluated with a fluorometric assay using the 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (MUNANA) substrate. Susceptibility to favipiravir (T-705) was assessed using plaque reduction assays. The NA affinity and velocity values were determined with NA enzymatic studies. Results. We identified an influenza A(H1N1)pdm09 E119D mutant that exhibited a marked increase in the 50% inhibitory concentrations against all tested NAIs (827-, 25-, 286-, and 702-fold for zanamivir, oseltamivir, peramivir, and laninamivir, respectively). The double E119D/H275Y mutation further increased oseltamivir and peramivir 50% inhibitory concentrations by 790- and >5000-fold, respectively, compared with the WT. The mutant viruses remained susceptible to favipiravir. The NA affinity and velocity values of the E119D variant decreased by 8.1-fold and 4.5-fold, respectively, compared with the WT. Conclusions. The actual emergence of a single NA mutation conferring pan-NAI resistance in the clinical setting reinforces the pressing need to develop new anti-influenza strategie

Allogeneic hematopoietic stem cell transplantation in non‐Hodgkin lymphoma in Switzerland, 30 years of experience: Sooner is better

Abstract Due to relatively high nonrelapse mortality (NRM), allogeneic hematopoietic stem cell transplantation (allo‐HSCT) in non‐Hodgkin's lymphoma (NHL) remains the ultimate line of treatment but the only curable approach in a setting of relapse/refractory disease. Here, we conducted a retrospective, multicenter, registry‐based analysis on patients who underwent allo‐HSCT for NHL in Switzerland, over 30‐year (1985–2020) period. The study included 301 allo‐HSCTs performed for NHL patients in three University Hospitals of Switzerland (Zurich, Basel and Geneva) 09/1985 to 05/2020. We assessed in univariate and multivariable analysis the impact on survivals (overall survival [OS], relapse free survival [RFS], relapse incidence [RI], and non‐treatment related mortality [NRM]). The maximum follow‐up was 25 years with median follow‐up for alive patients of 61 months. The median age at allo‐HSCT was 51 years. Three‐ and ‐year OS was ‐ 59.5% and 55.4%; 3‐ and 5‐year PFS was 50% and 44%; 3‐ and 5‐year NRM was 21.7% and 23.6%. RI at 3 and 5 years was 27.4% and 34.9%. In conclusion, our analysis of the entire Swiss experience of allo‐HSCT in patients with NHL shows promising 5‐ and possibly 10‐year OS and relatively acceptable NRM rates for such population, the majority being not in complete remission (CR) at the time of transplantation

Influence of cytogenetic abnormalities on outcome after allogeneic bone marrow transplantation for acute myeloid leukemia in first complete remission

AbstractCytogenetic abnormalities detected at diagnosis are recognized as important in predicting response to chemotherapy in acute myeloid leukemia (AML). However, there is controversy concerning the prognostic significance of karyotype for outcome after allogeneic bone marrow transplantation (allo-BMT) performed in first complete remission (CR1). This single-institution report describes allo-BMT for AML in CR1 and the effect of diagnostic cytogenetic findings on the results of that treatment. Between August 1981 and December 1999, 93 patients underwent related donor (n = 82) or unrelated donor (n = 11) BMT. Conditioning and GVHD prophylaxis were achieved predominantly with busulfan and cyclophosphamide and with cyclosporine and methotrexate, respectively. Seventy-nine (85%) of 93 patients had successful marrow karyotyping at diagnosis, and the patients were categorized into 3 prognostic groups based on the British Medical Research Council AML 10 trial classification: 15 patients(19%) were classified as having favorable risk [inv(16), t(8;2 1), t(15;17)]; 55 (70%) as having intermediate risk [no abnormality, +8, +21, +22, del(7q), del(9q), 11q23 rearrangement, and other numerical or structural abnormalities]; and 9 (11%) as having adverse risk [-5, del(5q), -7, 3q rearrangements, > or = 5 abnormalities, t(6;9), t(9;22)]. The median follow-up was 93 months (range, 16-241 months). The overall survival (OS) rate, event-free survival (EFS) rate, relapse rate, and treatment-related mortality (TRM) were not statistically different between the groups. The 5-year actuarial EFS rates for favorable, intermediate, and adverse risk groups were 58% (95% confidence interval [CI], 29%-79%), 58% (95% CI, 43%-70%), and 67% (95% CI 28%-88%), respectively. Reclassification of patients into cytogenetic prognostic subgroups according to Southwest Oncology Group criteria did not change these results. In univariate analysis, the only variable found to have a prognostic influence on OS (P = .04) and TRM (P = .03) was the type of donor (unrelated donor was linked to a worse prognosis), which was confirmed in multivariate analysis. Our study suggests that presentation karyotype has less prognostic significance for outcome following allo-BMT than for outcome following conventional chemotherapy. In particular, AML patients with poor prognostic cytogenetic changes in CR1 who are unlikely to be cured with chemotherapy alone may benefit from allo-BMT.Biol Blood Marrow Transplant 2002;8(8):435-43

GSTM1 and GSTT1 double null genotypes determining cell fate and proliferation as potential risk factors of relapse in children with hematological malignancies after hematopoietic stem cell transplantation.

PURPOSE This study aimed to retrospectively evaluate the genetic association of null variants of glutathione S-transferases GSTM1 and GSTT1 with relapse incidence in children with hematological malignancies (HMs) undergoing busulfan (BU)- containing allogeneic hematopoietic stem cell transplantation (HSCT) and to assess the impact of these variants on BU-induced cytotoxicity on the immortalized lymphoblastoid cell lines (LCLs) and tumor THP1 GST gene-edited cell models. METHODS GSTM1- and GSTT1-null alleles were genotyped using germline DNA from whole blood prior to a conditioning BU-based regimen. Association of GSTM1- and GSTT1-null variants with relapse incidence was analyzed using multivariable competing risk analysis. BU-induced cell death studies were conducted in GSTs- null and non-null LCLs and CRISPR-Cas9 gene-edited THP1 leukemia cell lines. RESULTS Carrying GSTM1/GSTT1 double null genotype was found to be an independent risk factor for post-HSCT relapse in 86 children (adjusted HR: 6.52 [95% Cl, 2.76-15.42; p = 1.9 × 10-5]). BU-induced cell death preferentially in THP1GSTM1(non-null) and LCLsGSTM1(non-null) as shown by decreased viability, increased necrosis and levels of the oxidized form of glutathione compared to null cells, while GSTT1 non-null cells showed increased baseline proliferation. CONCLUSION The clinical association suggests that GSTM1/GSTT1 double null genotype could serve as genetic stratification biomarker for the high risk of post-HSCT relapse. Functional studies have indicated that GSTM1 status modulates BU-induced cell death. On the other hand, GSTT1 is proposed to be involved in baseline cell proliferation

Outcomes and toxicity of allogeneic hematopoietic cell transplantation in chronic myeloid leukemia patients previously treated with second-generation tyrosine kinase inhibitors : a prospective non-interventional study from the Chronic Malignancy Working Party of the EBMT

Allogeneic hematopoietic cell transplantation (allo-HCT) remains a treatment option for patients with chronic myeloid leukemia (CML) who fail to respond to tyrosine kinase inhibitors (TKIs). While imatinib seems to have no adverse impact on outcomes after transplant, little is known on the effects of prior use of second-generation TKI (2GTKI). We present the results of a prospective non-interventional study performed by the EBMT on 383 consecutive CML patients previously treated with dasatinib or nilotinib undergoing allo-HCT from 2009 to 2013. The median age was 45 years (18-68). Disease status at transplant was CP1 in 139 patients (38%), AP or >CP1 in 163 (45%), and BC in 59 (16%). The choice of 2GTKI was: 40% dasatinib, 17% nilotinib, and 43% a sequential treatment of dasatinib and nilotinib with or without bosutinib/ponatinib. With a median follow-up of 37 months (1-77), 8% of patients developed either primary or secondary graft failure, 34% acute and 60% chronic GvHD. There were no differences in post-transplant complications between the three different 2GTKI subgroups. Non-relapse mortality was 18% and 24% at 12 months and at 5 years, respectively. Relapse incidence was 36%, overall survival 56% and relapse-free survival 40% at 5 years. No differences in post-transplant outcomes were found between the three different 2GTKI subgroups. This prospective study demonstrates the feasibility of allo-HCT in patients previously treated with 2GTKI with a post-transplant complications rate comparable to that of TKI-naive or imatinib-treated patients.Peer reviewe