Allogeneic haematopoietic stem cell transplant in patients with lower risk myelodysplastic syndrome: a retrospective analysis on behalf of the Chronic Malignancy Working Party of the EBMT

This corrects the article DOI: 10.1038/bmt.2016.266.

Risk factors for treatment failure after allogeneic transplantation of patients with CLL: a report from the European Society for Blood and Marrow Transplantation

For young patients with high-risk CLL, BTK-/PI3K-inhibitors or allogeneic stem cell transplantation (alloHCT) are considered. Patients with a low risk of non-relapse mortality (NRM) but a high risk of failure of targeted therapy may benefit most from alloHCT. We performed Cox regression analyses to identify risk factors for 2-year NRM and 5-year event-free survival (using EFS as a surrogate for long-term disease control) in a large, updated EBMT registry cohort (n= 694). For the whole cohort, 2-year NRM was 28% and 5-year EFS 37%. Higher age, lower performance status, unrelated donor type and unfavorable sex-mismatch had a significant adverse impact on 2-year NRM. Two-year NRM was calculated for good- and poor-risk reference patients. Predicted 2-year-NRM was 11 and 12% for male and female good-risk patients compared with 42 and 33% for male and female poor-risk patients. For 5-year EFS, age, performance status, prior autologous HCT, remission status and sex-mismatch had a significant impact, whereas del(17p) did not. The model-based prediction of 5-year EFS was 55% and 64%, respectively, for male and female good-risk patients. Good-risk transplant candidates with high-risk CLL and limited prognosis either on or after failure of targeted therapy should still be considered for alloHCT.

Prognostic pre-transplant factors in myelodysplastic syndromes primarily treated by high dose allogeneic hematopoietic stem cell transplantation: a retrospective study of the MDS subcommittee of the CMWP of the EBMT

Many pre-transplant factors are known to influence the outcome of allogeneic stem cell transplantation (SCT) treatment in myelodysplastic syndromes (MDS). However, patient cohorts are often heterogeneous by disease stage and treatment modalities, which complicates interpretation of the results. This study aimed to obtain a homogeneous patient cohort by including only de novo MDS patients who received upfront allogeneic SCT after standard high dose myelo-ablative conditioning. The effect of pre-transplant factors such as age, disease stage, transfusions, iron parameters and comorbidity on overall survival (OS), non-relapse mortality (NRM), and relapse incidence (RI) was evaluated in 201 patients. In this cohort, characterized by low comorbidity and a short interval between diagnosis and transplantation, NRM was the most determinant factor for survival after SCT (47 % after 2-year follow-up). WHO classification and transfusion burden were the only modalities with a significant impact on overall survival after SCT. Estimated hazard ratios (HR) showed a strongly increased risk of death, NRM and RI, in patients with a high transfusion-burden (HR 1.99; P = 0.006, HR of 1.89; P = 0.03 and HR 2.67; P = 0.03). The HR's for ferritin level and comorbidity were not significantly increased.

Quantitative monitoring of WT1 expression in peripheral blood before and after allogeneic stem cell transplantation for acute myeloid leukemia - a useful tool for early detection of minimal residual disease

Overexpressed Wilms tumor gene 1 (WT1) has been found in a majority of patients with acute myeloid leukemia (AML). The aim of this study was to confirm the applicability of WT1 expression measurement as a marker of minimal residual disease (MRD). The expression of WT1 gene was measured by real-time polymerase chain reaction in peripheral blood (PB) according to European Leukemia Net (ELN) recommendations. The WT1 expression was related to the expression of a reference gene Abelson (ABL) and the results were calculated as a number of WT1 copies related to 104 copies of ABL gene. The upper normal limit of WT1 expression was set at 50 copies of WT1 to 104 copies of ABL. Morphological, flow cytometry and chimerism examinations were evaluated according to standard protocols.A total of 51 AML patients with overexpressed WT1 gene were analyzed. The median follow-up after transplantation was 14 (2-72) months. WT1 expression levels exceeding the upper normal limit were considered as a sign of impending hematological relapse, in accord with morphological, flow cytometry and chimerism data, as well as with the expression of the specific fusion genes. Moreover, in 7 patients the rise of WT1 expression preceded all other standard methods. Patients with high WT1 expression before allogeneic hematopoietic stem cell transplantation (allo-HSCT) had significantly worse outcome than patients with low WT1 level. Examination of WT1 expression in PB of patients with AML is a useful tool for MRD monitoring. Moreover, the WT1 gene expression before stem cell transplantation seems to be of prognostic significance.

Genetic variability of cytomegalovirus glycoprotein O in hematopoietic stem cell transplant recipients

Genetic variation of cytomegalovirus (CMV) strains can correlate with their pathogenicity for immunocompromised patients. Glycoprotein O (gO), together with glycoprotein L and glycoprotein H, mediate the fusion of the viral envelope with the cell membrane and promotes virus penetration, envelopment, and release. The variability of gO might play a role in CMV cell tropism. The goal was a retrospective analysis of gO variability in a cohort of hematopoietic stem cell transplant (HSCT) recipients to determine the distribution of gO genotypes and to investigate their impact on clinical outcome and manifestation of CMV infection.

METHODS

In archived blood samples from 51 adult allogeneic HSCT recipients with active CMV infection, gO was analyzed by sequencing the N-terminal domain of the UL74 gene using the dye deoxy termination method.

RESULTS

The gO1 and gO2 clades were most common (39% and 20%, respectively, and gO3 was associated with higher risk of symptomatic infection (P = 0.026 in multivariant analysis). Despite being associated with higher antigenemia levels (P = 0.02), gO4 had the best survival and lower rate of CMV recurrence. No significant differences were found in clinical manifestation and outcome of CMV disease between patients with various gO clades. Because CMV strains sharing an identical gO sequence differed in glycoprotein B genotypes, sequencing the N-terminal part of the gO gene does not seem to be optimal for the identification of strains.

CONCLUSIONS

gO genotyping may contribute to the biological characterization of CMV strains in HSCT recipients.

The impact of HLA matching on long-term transplant outcome after allogeneic hematopoietic stem cell transplantation for CLL: a retrospective study from the EBMT registry

We analyzed 368 chronic lymphocytic leukemia patients who underwent allogeneic hematopoietic stem cell transplantation reported to the EBMT registry between 1995 and 2007. There were 198 human leukocyte antigen (HLA)-identical siblings; among unrelated transplants, 31 were well matched in high resolution ('well matched' unrelated donor, WMUD), and 139 were mismatched (MM), including 30 matched in low resolution; 266 patients (72%) received reduced-intensity conditioning and 102 (28%) received standard. According to the EBMT risk score, 11% were in scores 1-3, 23% in score 4, 40% in score 5, 22% in score 6 and 4% in score 7. There was no difference in overall survival (OS) at 5 years between HLA-identical siblings (55% (48-64)) and WMUD (59% (41-84)), P=0.82. In contrast, OS was significantly worse for MM (37% (29-48) P=0.005) due to a significant excess of transplant-related mortality. Also OS worsened significantly when EBMT risk score increased. HLA matching had no significant impact on relapse (siblings: 24% (21-27); WMUD: 35% (26-44), P=0.11 and MM: 21% (18-24), P=0.81); alemtuzumab T-cell depletion and stem cell source (peripheral blood) were associated with an increased risk. Our findings support the use of WMUD as equivalent alternative to HLA-matched sibling donors for allogeneic HSCT in CLL, and justify the application of EBMT risk score in this disease.

[Genotyping of viral glycoprotein B (gB) in hematopoietic stem cell transplant recipients with active cytomegalovirus infection: analysis of the impact of gB genotypes on the patients' outcome]

AIM OF THE STUDY

Genetic variation of CMV strains may correlate with their pathogenicity for immunocompromised patients. On the basis of sequence variation in the UL55 gene encoding the most abundant viral envelope glycoprotein gB, CMV can be classified into four major gB genotypes. The aim of the study was the analysis of the distribution of gB genotypes in a cohort of haematopoietic stem cell transplant (HSCT) recipients and of the correlation of genetic polymorphisms with clinical outcomes and manifestation of CMV infection.

MATERIAL AND METHODS

Archived DNA isolates from consecutive blood samples of 53 adult allogeneic HSCT recipients with active CMV infection, transplanted in 2004-2005, were used for the genetic analysis. HCMV gB genotyping was performed by restriction fragment length polymorphism (RFLP) analysis and sequencing of the central variable region of UL55. The association of gB genotypes with selected clinical parameters was assessed by multivariate analysis after adjustment for graft donor type, HLA-matching and anti-thymocyte immunoglobulin (ATG) therapy.

RESULTS

gB1, gB2, gB3, and gB4 genotypes were detected in 30%, 17%, 26% and 4% of the patients, respectively. An atypical gB genotype was found in one patient. Co-infection with two or more gB genotypes was revealed in 17% of the patients. The distribution of gB genotypes did not vary in time, despite the fact that the patients transplanted in 2005 had more severe CMV infection with higher viral loads in the blood than those transplanted in 2004. gB1 was associated with a lower viral load (p = 0.046) and a milder course of symptomatic CMV infection, but with a higher rate of acute graft versus host disease (OR 3.4; p = 0.067). Pancytopenia was less frequent in the patients infected with gB3 (OR 0.09; p = 0.075). In contrast, gB2-infected patients had a worse outcome of CMV infection with a higher rate of organ involvement and were less responsive to antiviral therapy (OR 6.65 and 0.18; p = 0.15 and 0.12, respectively). The prognostic impact of co-infection with two or more gB genotypes was not shown.

CONCLUSIONS

gB genotype may have an impact on the course of CMV infection and its complications in HSCT recipients. Nevertheless, these results need to be tested on a larger group of patients in the context of genetic variability of other functionally important viral genes. The characterization of viral genetic factors determining CMV pathogenesis will be of relevance to the treatment of patients at high risk of CMV infection.

Reduced-intensity conditioning for allogeneic stem cell transplantation in patients with chronic myeloid leukemia is associated with better overall survival but inferior disease-free survival when compared with myeloablative conditioning - a retrospective study of the Czech National Hematopoietic Stem Cell Transplantation Registry

Allogeneic stem cell transplantation (AlloSCT) has been currently recommended in the treatment of patients with chronic myeloid leukemia (CML) as a second option after imatinib failure or in selected group of patients with high-risk CML and low risk for transplant-related mortality. The actual role of reduced-intensity conditioning (RIC) before AlloSCT in CML patients has not been yet conclusively established. The Czech National Hematopoietic Stem Cell Transplantation Registry has conducted a retrospective analysis of all patients (n=29) transplanted after RIC from the Registry database containing 295 patients with CML transplanted in the Czech Republic in years 1988-2005 and compared them with patients at comparable age (median age 48.3 and 50.6 years, respectively; p=0.587) transplanted during the same period of time using conventional myeloablative conditioning (n=26). Survival advantage of patients transplanted after RIC has been confirmed by log rank test (p=0.036) despite the fact that the relapse rate was significantly higher in RIC group (44.8% versus 0%). Both groups did not differ significantly in the use of voluntary unrelated donors, type of the grafts and in incidence of acute graft versus host disease (GVHD). However, there were trends for higher risk of CML and higher use of unrelated donors in the myeloablative group while peripheral stem cell grafts and chronic GVHD were observed more frequently in the RIC group. Transplant-related mortality was the leading cause of death in both groups of patients. Our results should be interpreted with caution because they may be influenced by small groups of subjects and also the impact of patients with high EBMT risk score on inferior survival in the myeloablative group cannot be fully eliminated. More retrospective and prospective studies are needed to elucidate the actual role of RIC before AlloSCT for CML.

Mycobacterial Infection: A Difficult and Late Diagnosis in Stem Cell Transplant Recipients

The Infectious Diseases Working Party of the European Blood and Marrow Transplant Group conducted a survey to obtain information about the frequency, presentation, and treatment of mycobacterial infection (MBI) in stem cell transplant (SCT) recipients. Among 29 centers, MBI was diagnosed in 0.79% of 1513 allogeneic and 0.23% of 3012 autologous SCT recipients during 1994-1998 a median of 160 days after transplantation. The mean interval between first symptoms and diagnosis was 29 days and was still longer for patients with atypical MBI or recipients of corticosteroid therapy. The prevalence of MBI was highest among those who received matched unrelated or mismatched STCs from related donors. Of 31 patients, 20 had tuberculosis, 8 had atypical MBI, and 3 had diagnoses based on histological findings only. Five patients (16%) died, all of whom had received an allogeneic SCT. Because of the increased numbers of unmatched donors and transplantation programs in countries with a high prevalence of tuberculosis, constant vigilance is required to early detect MBI in SCT recipients.

Response to imatinib in patients who relapse after allogeneic stem cell transplantation for chronic myeloid leukemia

We studied 128 patients with chronic myeloid leukemia (CML) relapsing after allogeneic stem cell transplantation (SCT). Disease at the time of treatment with Imatinib was in chronic phase (CP) in 51 patients, accelerated phase (AP) in 31 and blastic crisis (BC) in 46. Of the 51 patients in CP, 14 were in cytogenetic and two in molecular relapses. The median interval between relapse and Imatinib therapy was 5 months (0-65). A total of 50 patients had failed treatment with donor lymphocyte infusions prior to Imatinib. The overall hemato-logical response rate was 84% (98% for patients relapsing in CP). The complete cytogenetic response (CCR) was 58% for patients in CP, 48% for AP and 22% for patients in BC. Complete molecular responses were obtained in 25 patients (26%), of whom 21 were in CP or AP. With a median follow-up of 9 months, the estimated 2-year survival for CP, AP and BC patients was 100, 86 and 12%, respectively. Out of 79 evaluable patients, 45 (57%) achieved full donor and 11 (14%) mixed chimerism after Imatinib. We conclude that Imatinib has significant activity against CML in relapse after allogeneic SCT. Durable cytogenetic and molecular remissions are obtainable in patients in CP.

Are human platelet alloantigens (HPA) minor transplantation antigens in clinical bone marrow transplantation?

The role of human platelet alloantigens (HPA) in clinical bone marrow allotransplantation was investigated. The leading hypothesis was that HPA alloepitopes act as minor histocompatibility antigens and aggravate graft-versus-host disease (GVHD). To exclude the effect of MHC disparity, only HLA identical donor-recipient pairs were entered into the study. The influence of HPA compatibility on overall survival, occurrence of relapses and haematopoietic recovery was also investigated. A total of 223 patients who received a graft from an HLA-identical sibling, genotyped for HPA -1, -2, -3, -4 and -5, were observed over a post-transplant period of 24 months following the protocol recommended by EBMT. The data from patients having received grafts from HPA compatible donors were compared to data from patients having received grafts that were mismatched in HPA allotypes in the GVH direction. Analysis of the incidence of acute and chronic (GVHD), overall survival, relapse incidence, haematopoietic recovery and some other clinical parameters did not reveal any significant difference between the HPA-matched and -mismatched groups of patients, regardless of their age. Our results give no evidence that HPA-1, -2, -3 and -5 alloantigens should be considered minor transplantation antigens in clinical bone marrow transplantation.

[Interactions of cytokines with their receptors in the regulation of hematopoiesis, clinical and diagnostic applications]

A short review on the interaction of hematopoietic growth factors with their receptors in the regulation of hematopoiesis. The introductory notes on the nature of cytokines and cytokine receptors, their biological and physicochemical properties as well as clinical and diagnostic consequences are mentioned.

The buccalin-related neuropeptides: isolation and characterization of an Aplysia cDNA clone encoding a family of peptide cotransmitters

The buccalin-related peptides, buccalin A and buccalin B, are members of a family of cotransmitters that modulate neuromuscular transmission in Aplysia. In this study, a third buccalin-related peptide, buccalin C, was purified from neuronal elements in the accessory radula closer, a muscle involved in the animal's feeding behavior. Oligonucleotide probes based upon the amino acid sequence of buccalin C were used to isolate cDNA clones that encode a buccalin precursor polypeptide. The buccalin precursor contains 19 distinct buccalin-related peptides, several of which are present in multiple copies. The buccalin gene appears to be present in a single copy, with one allele containing a small insert. Expression of this gene occurs in a tissue-specific manner and mRNA transcripts are abundant within neurons in the Aplysia CNS. This large family of neuropeptides may exert extraordinarily complex modulatory actions at synapses where they serve as cotransmitters.

The myomodulin-related neuropeptides: characterization of a gene encoding a family of peptide cotransmitters in Aplysia

The myomodulin-related peptides comprise a family of cotransmitters that modulate neuromuscular signaling in the feeding system of Aplysia. In this study, cDNA clones encoding a myomodulin precursor polypeptide were isolated and characterized. This precursor contains seven different myomodulin-related peptides, one of which, myomodulin A, is present in 10 contiguous copies. The sequence of a myomodulin genomic clone indicates that all of these myomodulin-related peptides are encoded on a single exon. The myomodulin gene is expressed in a tissue-specific manner and myomodulin mRNA is localized to specific neurons in the Aplysia CNS. The presence of multiple related neuropeptides can greatly increase the range and precision of signaling at synapses where they act as modulator cotransmitters.

Characterization of two genes encoding human steroid 11 beta-hydroxylase (P-450(11) beta)

Steroid 11 beta-hydroxylase (P-450(11) beta) is a mitochondrial cytochrome P-450 enzyme necessary for cortisol biosynthesis. Deficiency of 11 beta-hydroxylase causes a hypertensive form of congenital adrenal hyperplasia. A partial cDNA clone encoding this enzyme has been previously isolated and the corresponding gene, CYP11B1, mapped to human chromosome 8q. This gene has now been isolated along with a second linked homologous gene, CYP11B2. Each gene contains nine exons. The eight introns are identical in location to the introns of the CYP11A gene encoding another mitochondrial P-450 enzyme, cholesterol desmolase, confirming that 11 beta-hydroxylase and cholesterol desmolase are in the same gene family within the P-450 superfamily. The nucleotide sequences of CYP11B1 and B2 are 95% identical in coding regions and about 90% identical in introns. The putative proteins encoded by CYP11B1 and B2 each contain 503 amino acids including a 24-residue signal peptide and have sequences that are 93% identical to each other and 75% identical to the predicted sequence of bovine P-450(11) beta. There are no obviously deleterious mutations in coding sequences of CYP11B2. However, the 5'-flanking regions of CYP11B1 and B2 have diverged considerably, and B2 transcripts were not detected in human adrenal mRNA or among cDNA clones.

Characterization of frequent deletions causing steroid 21-hydroxylase deficiency

Steroid 21-hydroxylase deficiency is caused by mutations in the CYP21B gene. This gene and a highly homologous pseudogene, CYP21A, alternate with the C4A and C4B genes encoding the fourth component of complement. Classical deficiency alleles are frequently caused by deletions of CYP21B or by gene conversions that transfer deleterious mutations from the CYP21A pseudogene to CYP21B. Gene conversions involving restriction enzyme sites that distinguish CYP21A [e.g., 3.2-kilobase (kb) Taq I fragment] and CYP21B (3.7-kb Taq I fragment) might be confused with actual deletions of CYP21B. To determine the incidence of this type of gene conversion, 15 chromosomes (in 13 families) with absent 3.7-kb Taq I fragments were studied. When hybridized with a 21-hydroxylase probe, all of these chromosomes were associated with absent 2.9-kb Kpn I fragments, 14 of 15 were associated with absent 2.4-kb Bgl II/EcoRI fragments, and 13 of 15 were associated with absent 10-kb Bgl II/EcoRI and 12-kb EcoRI fragments. Thirteen of 15 chromsomes had absent 6.0- or 5.4-kb Taq I fragments when hybridized with a C4 probe. Thus, 2 of 15 chromosomes do not carry deletions and may represent gene conversions; 13 of 15 chromosomes studied have a deletion of approximately equal to 30 kb, leaving behind the C4A gene and a single CYP21A-like gene. Hybridization with specific oligonucleotide probes showed that in all 13 cases this remaining CYP21 gene carried an 8-base-pair deletion, typical of CYP21A, that prevents synthesis of a functional protein. Thus, gene conversions are rarely confused with deletions as a cause of 21-hydroxylase deficiency.

Cloning of cDNA encoding steroid 11 beta-hydroxylase (P450c11)

We have isolated bovine and human adrenal cDNA clones encoding the adrenal cytochrome P-450 specific for 11 beta-hydroxylation (P450c11). A bovine adrenal cDNA library constructed in the bacteriophage lambda vector gt10 was probed with a previously isolated cDNA clone corresponding to part of the 3' untranslated region of the 4.2-kilobase (kb) mRNA encoding P450c11. Several clones with 3.2-kb cDNA inserts were isolated. Sequence analysis showed that they overlapped the original probe by 300 base pairs (bp). Combined cDNA and RNA sequence data demonstrated a continuous open reading frame of 1509 bases. P450c11 is predicted to contain 479 amino acid residues in the mature protein in addition to a 24-residue amino-terminal mitochondrial signal sequence. A bovine clone was used to isolate a homologous clone with a 3.5-kb insert from a human adrenal cDNA library. A region of 1100 bp was 81% homologous to 769 bp of the coding sequence of the bovine cDNA except for a 400-bp segment presumed to be an unprocessed intron. Hybridization of the human cDNA to DNA from a panel of human-rodent somatic cell hybrid lines and in situ hybridization to metaphase spreads of human chromosomes localized the gene to the middle of the long arm of chromosome 8. These data should be useful in developing reagents for heterozygote detection and prenatal diagnosis of 11 beta-hydroxylase deficiency, the second most frequent cause of congenital adrenal hyperplasia.