Availability of HLA-allele-matched unrelated donors and registry size: Estimation from haplotype frequency in the Italian population.

In Italy, an HLA-matched unrelated donor is currently the primary donor when a HLA matched sibling is not found for allogeneic haematopoietic stem cell transplantation (HSCT). Better outcomes for transplantation require optimal matching between donor and recipient at least at the HLA-A, -B, -C, and -DRB1 loci; therefore, the availability of HLA-matched unrelated donors is important. The enormous HLA polymorphism has always necessitated registries with a large number of individuals in order to be able to provide well-matched donors to a substantial percentage of patients. In order to increase the efficiency of the Italian Bone Marrow Donor Registry (IBMDR) in providing Italian patients with a suitable donor, the probability of finding an HLA-A, -B, -C, and -DRB1 allele-matched (8/8) or a single mismatch unrelated donor (7/8) was estimated in this study according to IBMDR size. Using a biostatistical approach based on HLA haplotype frequencies of more than 100,000 Italian donors enrolled in the IBMDR and HLA-typed at high-resolution level, the probability of finding an 8/8 HLA-matched donor was 23.8%; 33.4%; and 41.4% in simulated registry sizes of 200,000; 500,000; and 1,000,000 donors; respectively. More than 2 million recruited donors are needed to increase the likelihood of identifying an HLA 8/8 matched donor for 50% of Italian patients. If one single mismatch at HLA I class loci was accepted, the probability of finding a 7/8 HLA-matched donor was 62.8%; 73.7%; and 80.3% in 200,000 donors; 500,000; and 1,000,000 donors; respectively. Using the regional haplotype frequencies of IBMDR donors, the probability of recruiting a donor with a new HLA phenotype, in the different Italian regions, was also calculated. Our findings are highly relevant in estimating the optimal size of the national registry, in planning a cost-effective strategy for donor recruitment in Italy, and determining the regional priority setting of recruitment activity in order to increase the phenotypic variability of IBMDR as well as its efficiency.

Chronic GVHD is associated with lower relapse risk irrespective of stem cell source among patients receiving transplantation from unrelated donors.

Chronic GVHD (cGVHD) has been associated with reduced risk of relapse after allo-SCT for onco-hematological disease due to a graft-vs-malignancy effect. Here we retrospectively analyzed a series of 802 adult patients transplanted from unrelated donors and found that cGVHD was associated with significantly lower relapse and that the limited form was associated with a survival advantage: hazard ratio for OS=0.63 (0.46-0.87); P=0.004; this was due to combination of relapse reduction and similar non-relapse mortality with respect to patients without cGVHD. Importantly, the graft-vs-malignancy effect observed here did not differ when PBSC or BM were used as stem cell source, thus suggesting that the protective effect of limited cGVHD is similar after PBSC- or BM-based transplantation. These findings could have practical implications and suggest no qualitative difference between cGVHD occurring after transplantation performed with different stem cell sources.

Outcome of patients activating an unrelated donor search: the impact of transplant with reduced intensity conditioning in a large cohort of consecutive high-risk patients.

An unrelated donor (UD) search was submitted to the Italian Bone Marrow Donor Registry between February 2002 and December 2004, for 326 consecutive patients with hematological malignancies, eligible for a reduced intensity conditioning (RIC) UD transplant. Only two regimens were allowed: melphalan, alemtuzumab, fludarabine and total body irradiation of 200 cGy (regimen A) and thiotepa, cyclophosphamide, anti-thymocyte globulin (regimen B). The outcome of patients receiving an UD transplant (n=121) was compared with patients who did not find a donor (n=205), in a time dependent analysis, correcting for time to transplant. The median follow up from activation of donor search was 6.1 years. UD transplant was associated with a significantly better survival in patients with acute leukemia and non-Hodgkin's lymphoma (NHL) whereas only a favorable trend was documented for Hodgkin's disease. No survival benefit was registered for chronic leukemias. The outcome of the two different conditioning regimens was comparable, in terms of survival, transplant-related mortality and graft versus host disease. In conclusion, finding an UD and undergoing a RIC transplant significantly improves survival of patients with acute leukemia and NHL. The advantage is less clear for HD and chronic leukemias. The role of different conditioning regimens remains to be elucidated by prospective clinical trials.

The conundrum of HLA-DRB1*14:01/*14:54 and HLA-DRB3*02:01/*02:02 mismatches in unrelated hematopoietic SCT.

Uncertainty still exists on the role of polymorphisms outside the HLA-DRB1 binding site or inside the HLA-DRB3 binding groove in unrelated hematopoietic SCT (HSCT). The ideal model to solve the conundrum consists of the transplants mismatched for HLA-DRB1*14:01/*14:54 and/or for HLA-DRB3*02:01/*02:02. A task force was set up in Italy to recruit transplanted pairs defined as HLA-DRB1*14:01 before 2006, the year crucial for the proper definition of the HLA-DRB1*14:54 allele in molecular biology. Out of 2723 unrelated pairs, 189 transplanted in Italy from 1995 to 2006 were HLA-DRB1*14:01 positive; 103/189 pairs with good historical DNA were retyped for HLA-DRB1*14 and HLA-DRB3 at-high resolution level; 31/103 pairs had HLA-DRB1*14 and/or HLA-DRB3 mismatched; 99/103, having complete clinical data, underwent statistical analysis for OS, TRM, disease-free survival and acute and chronic GvHD. No significant involvement of HLA-DRB1*14:01/*14:54 or HLA-DRB3*02:01/*02:02 mismatches was found, either alone or combined. Our findings suggest that disparities at exon 3 of the HLA-DRB1 gene seem unlikely to influence the outcome after HSCT. The same may be envisaged for HLA-DRB3(*)02:01 and (*)02:02 alleles which, although differing in the Ag binding site, seem unable to modulate an appreciable immune response in an HSCT setting.

Standards, regulations and accreditation for registries involved in the worldwide exchange of hematopoietic stem cell donors and products.

The World Marrow Donor Association (WMDA) is working closely with other international organizations working in cellular therapy such as the Worldwide Network for Blood and Marrow Transplantation (WBMT) to develop and maintain global recommendations and requirements for a standardized practice. WMDA launched its registry accreditation program in September 2003. Since then, 17 of the 71 hematopoietic stem cell donor registries worldwide have been accredited. These accredited registries list over 80% of the hematopoietic stem cell donors and umbilical cord blood units listed in the database of BM Donors Worldwide. The goal of the WMDA Standards and Accreditation process is to protect donors while serving the needs of patients who are urgently seeking histocompatible donors in worldwide searches. These activities address the increasing governmental regulations regarding the quality and safety of stem cells collected internationally for national patients.

Pre-emptive treatment of acute GVHD: a randomized multicenter trial of rabbit anti-thymocyte globulin, given on day+7 after alternative donor transplants.

We have previously shown that hemopoietic stem cell transplant (HSCT) recipients can be stratified on day+7 as having low, intermediate or a high risk of transplant-related mortality (TRM). With the aim of reducing TRM and GVHD, intermediate and high-risk patients (n=170) were randomized to receive anti-thymocyte globulin (ATG, thymoglobuline) on day+7 (n=84) or no treatment (n=86) (controls). There was a reduction of TRM from 35% in controls to 29% in ATG patients (P=0.3), of acute GVHD III-IV from 15 to 5% (P=0.02) and of chronic GVHD from 26 to 11% (P=0.03); survival was comparable. The predictive value of the day+7 score on TRM was confirmed for controls (19 vs 42% for intermediate vs high risk, respectively, P=0.03), whereas ATG abrogated this predictive effect (29 vs 29%). ATG reduced GVHD (P=0.006) in high-risk patients, but not in patients with an intermediate risk. In conclusion, we confirm that TRM can be predicted on the basis of day+7 laboratory values, after alternative donor HSCT; in high-, but not intermediate-risk patients, the administration of ATG on day+7 reduces GVHD. These results may represent a platform for risk-adapted post transplant immune modulation.

HLA matching affects clinical outcome of adult patients undergoing haematopoietic SCT from unrelated donors: a study from the Gruppo Italiano Trapianto di Midollo Osseo and Italian Bone Marrow Donor Registry.

The importance of HLA donor-recipient matching in unrelated haematopoietic SCT (HSCT) is the subject of debate. In this retrospective study, we analyzed 805 adult patients from the Italian Registry receiving HSCT for a haematological malignancy from January 1999 to June 2006 and correlated the degree of HLA matching with transplant outcome. All patient-donor pairs had high-resolution typing at HLA-A, -B, -C, -DRB1 and -DQB1. There was a significantly higher risk of overall mortality, non-relapse mortality, graft failure and acute GVHD (aGVHD) for patients receiving HSCT from an unrelated donor with one or more low- or high-resolution mismatch/es (Mm/s). When only a single HLA Mm is present (9/10 matched pairs), mortality risk is higher than among 10/10 matched pairs in patients transplanted with acute leukaemia in the first CR ('early' patients) but not in the other patients (advanced patients): HR=1.69, 95% CI=0.94-3.02, P=0.08; HR=1.03, 95% CI=0.80-1.32, P=0.82, for early and advanced patients, respectively. These results confirm that the advantage of a 10/10 match has a greater effect in early patients, thus suggesting that a 9/10 matched donor can be chosen in patients with advanced disease lacking a rapidly available 10/10 matched one.

Strategies of the donor search for children with second CR ALL lacking a matched sibling donor.

During the last 10 years, the number of alternative Haematopoietic stem cell transplantations (HSCTs) performed on children in Europe has increased significantly and has reached 61% of the allografts. In this paper, we provide practical guidelines to help define an algorithm for the treatment of children relapsing during or after first-line chemotherapy for ALL and lacking a matched sibling donor. A simultaneous search for an unrelated donor and for a cord blood unit should be started. This study focuses mainly on the effects of some factors on survival in an effort to highlight the influence that these factors have on our choices. Matching the patient for HLA-A, -B, -C and -DRB1 alleles remains the top priority: a single HLA class I or II allele mismatch has no influence on survival, while multiple mismatching for more than one class I allele and simultaneous disparities in class I and II alleles increase mortality. The impact of additional mismatches for HLA-DQ and -DP loci on survival is still controversial. Young donor age is the most important factor that has a significant effect on better survival from among several other factors, including CMV sero-status, gender and ABO. An 18- to 30-year-old, 8/8 allele-matched donor (excluding allele matching at DQB1) or for many teams 10/10 allele-matched donor; or a 4 out of 6 (considering Ag HLA-A, -B and allelic typing of DRB1) CB unit containing more than 3.0 x 10(7) nuclear cells is considered by most institutions. The choice should be made on the basis of urgency. If a donor or a CB unit is not found within an appropriate time frame, generally less than 3 months after obtention of remission, haploidentical HSCT should be offered. Some institutions consider haploidentical HSCT the second therapeutic option when a matched donor is not available.

Haematopoietic stem cell donor registries: World Marrow Donor Association recommendations for evaluation of donor health.

The ability to identify unrelated haematopoietic stem cell donors in one country for recipients in another country requires cooperation and standardization in many areas. The donor assessment and testing are very important issues affecting quality and safety of donation. This special report details the World Marrow Donor Association's recommended procedures regarding the medical evaluation of donors, with the intent to protect the volunteer from the risk to damage his health and to offer the recipient the appropriate quality of stem cells. This document describes criteria for permanent or temporary deferral, guidelines for risk evaluation of infectious disease, examples of conditions requiring assessment and questionnaires designed to elicit relevant information about a donor's medical history and general health.

Genetic insights into the disease mechanisms of type II mixed cryoglobulinemia induced by hepatitis C virus.

The ability of the immune system to distinguish between self and non-self is critical to the functioning of the immune response. A breakdown in these mechanisms can lead to the onset of autoimmune disease. Clinical and molecular data suggest that shared immunogenetic mechanisms lead to the autoimmune process. The most studied part of the autoimmune process is the human leukocyte antigen (HLA) region. Recently, progress has been made in narrowing down HLA cluster classifications based on structural and functional features of HLA alleles. Using this approach we have investigated 175 patients with hepatitis C virus (HCV)-induced type II cryoglobulinemia (MC), and compared them to a control group of 14,923 bone marrow donors. Additionally, we investigated the frequency of HLA homozygosity in the same groups of subjects. Our results provide evidence of a role for DR5 and DQ3 HLA class II clusters and a higher frequency of HLA homozygous leading to the clinical outcome of type II mixed cryoglobulinemic autoimmune disease. The DR5 cluster is characterized by a Glu in beta 9 and its polymorphism is connected with preferred anchors at beta 9 of the binding peptide, while the DQ3 cluster is characterized by Glu B86 and Leu B87, which allows the binding of large hydrophobic amino acids at p1 of the binding peptide. The mechanisms by which variations in HLA lead to autoimmunity remain unknown, although they are likely to be mediated by continuous presentation of HCV epitopes to T cells and a genetic background that limits the effective clearance of HCV. The results presented in this paper have increased our knowledge of the mechanism of autoimmune disease and B-cell lymphoproliferation during HCV infection. The work was performed in accordance with the principles of the 1983 Declaration of Helsinki. There is no conflict of interest.

Allogeneic hemopoietic stem cell transplants for patients with relapsed acute leukemia: long-term outcome.

We assessed the long-term outcome of patients with relapsed acute myeloid (n=86) or acute lymphoid leukemia (n=66), undergoing an allogeneic hemopoietic stem cell transplantation in our unit. The median blast count in the marrow was 30%. Conditioning regimen included total body irradiation (TBI) (10-12 Gy) in 115 patients. The donor was a matched donor (n=132) or a family mismatched donor (n=20). Twenty-two patients (15%) survive disease free, with a median follow-up of 14 years: 18 are off medications. The cumulative incidence of transplant related mortality is 40% and the cumulative incidence of relapse related death (RRD) is 45%. In multivariate analysis of survival, favorable predictors were chronic graft-versus-host disease (GvHD) (P=0.0003), donor other than family mismatched (P=0.02), donor age less than 34 years (P=0.02) and blast count less than 30% (P=0.07). Patients with all four favorable predictors had a 54% survival. In multivariate analysis of relapse, protective variables were the use of TBI (P=0.005) and cGvHD (P=0.01). This study confirms that a fraction of relapsed leukemias is cured with an allogeneic transplant: selection of patients with a blast count <30%, identification of young, human leukocyte antigen-matched donors and the use of total body radiation may significantly improve the outcome.

Progenitor cells trapped in marrow filters can reduce GvHD and transplant mortality.

A bone marrow harvest is filtered either in the operating room, in the laboratory or during infusion to the patient. Filters are usually discarded. Little is known of haemopoietic progenitor cells (HPCs) trapped in the filters. The aim of the study was to evaluate HPC content in the filters and to assess the outcome of transplants with filter-discarded or filter-recovered cells. Haemopoietic progenitors were grown from filters of 19 marrow transplants. We then compared the outcome of 39 filter-recovered transplants from HLA-identical siblings (years 2001-2004) with a matched cohort of 43 filter-discarded marrow grafts (years 1997-2000). Filters contained on average 21% long-term culture-initiating cells (LTC-IC) and 15% fibroblasts colony-forming units (CFU-F) of the total progenitor cell content. Filter-discarded transplants had significantly more grade II-IV graft-versus-host disease (GvHD) (42 vs 15%, P=0.008) as compared to filter-recovered transplants, and more transplant-related mortality (TRM) (20 vs 3%, P=0.04). The actuarial survival at 5 years is 69 vs 87%, respectively (P=0.15). This study suggests that a significant proportion of LTC-IC is lost in the filters together with CFU-F. Recovery and add back of progenitors trapped in the filters may reduce GvHD and TRM.

RAR-mediated epigenetic control of the cytochrome P450 Cyp26a1 in embryocarcinoma cells.

Retinoic acid (RA) is a signaling molecule that plays a pivotal role in major cellular processes and vertebrate development. RA action is mediated by specialized transcription factors, the nuclear RA receptors (RARs), which regulate the transcription of genes containing a RA-responsive element (RARE). Here we demonstrate that the genes for the RA-receptor RARbeta2 and the cytochrome P450 RA-specific hydrolase Cyp26a1 involved in RA catabolism are coordinately regulated by RA. We found that both RARbeta2 and Cyp26a1 genes are epigenetically silenced in the absence of DNA methylation in RAC65, a P19 embryocarcinoma cell line derivative carrying a dominant-negative RARalpha mutant and resistant to the growth-inhibitory and differentiation effects of RA. In response to RA, RARbeta2 transcription is epigenetically regulated by RARalpha. Similarly, we found that Cyp26a1 transcription is epigenetically regulated by RARbeta2. Knocking down RARbeta2 transcription by RNA interference in wild-type P19 cells, with an intact RARalpha, induced Cyp26a1 transcriptional repression in the absence of DNA methylation. Concomitantly, cells developed RA resistance and did not undergo RA-induced neuron differentiation. Apparently, RARalpha, RARbeta2 and Cyp26a1 are components of a RA-regulated gene network. Factors affecting an upstream gene of the network can trigger repressive chromatin changes -- which are propagated in a domino fashion - at downstream genes of the network. This study also shows that chromatin inactivity, and consequent transcriptional silencing, can be achieved in the absence of DNA methylation.

Impact of marrow unrelated donor search duration on outcome of children with acute lymphoblastic leukemia in second remission.

We analyzed the outcome of 167 consecutive children with second CR acute lymphoblastic leukemia (ALL), for whom an unrelated donor (UD) search was activated between 1989 and 1998 at a median time of 2 months after relapse. A suitable donor was identified for 70 patients at 1 year and 6.5 months before and after 1995 from search activation, respectively; a further leukemia relapse occurred during the search in 94 children at a median of 4 months after search activation, 36 of whom underwent UD (14) or other types of transplant (22), beyond second CR, while 58 died of progressive disease. Of 73 patients not experiencing a second relapse, 64 underwent UD (46) or other types of transplant (18), while nine proceeded with chemotherapy, and only four of them survived. The 3-year disease-free survival (DFS) from second CR for the 167 patients is 15.1%, whereas 3-year DFS after transplant for the 60 UD and 40 alternative donor transplanted children is 31.6 and 25.4%, respectively. In conclusion, a further relapse is the main factor adversely affecting outcome of children with second CR ALL. Thus, for these patients, the search should be activated early after relapse and either a UD or an alternative transplant should be performed as early as possible.

Resveratrol structure and ceramide-associated growth inhibition in prostate cancer cells.

Resveratrol (3,4',5-trans-trihydroxystilbene) is a dietary polyphenol with chemopreventive properties present in grapes, red wine, peanuts and other edible products. The antiproliferative and proapoptotic effect of resveratrol in breast cancer cells can be traced to the accumulation of ceramide. In this study we demonstrate that resveratrol can also exert antiproliferative/proapoptotic effects in association with the accumulation of endogenous ceramide in the androgen receptor (AR)-negative prostate cancer cell line, PC3. Notably, resveratrol shares with other ceramide-inducing agents a phenolic moiety on its structure. For this reason we hypothesize that the phenolic moiety is critical for the ceramide-associated growth-inhibitory effects of resveratrol. We compared the ability to induce both ceramide increase and growth inhibition in PC3 cells of resveratrol and three resveratrol analogs: piceatannol (3,3',4',5-trans-tetrahydroxystilbene), with an additional hydroxyl group in the 3' position; trans-stilbene, the nonhydroxylated analog; and the semisynthetic 3,4',5-trimethoxy-trans-stilbene (TmS), with methoxyl groups in lieu of the hydroxyl groups. Of the three stilbenoids, only piceatannol (and not stilbene or TmS) produced ceramide-associated growth inhibition. These data point to the phenolic moiety of stilbenoids as a critical structural feature necessary to induce ceramide-associated growth inhibition.

Improvement over time in outcome for children with acute lymphoblastic leukemia in second remission given hematopoietic stem cell transplantation from unrelated donors.

Aims of this study were to verify whether reduction in transplant-related mortality (TRM) of children with acute lymphoblastic leukemia (ALL) in second complete remission (CR) given allogeneic hematopoietic stem cell transplantation (HSCT) from unrelated volunteers has occurred over time and to investigate the role of other variables on the probabilities of relapse, TRM and event-free survival (EFS). We compared results obtained in 26 children given HSCT before January 1998 with those of 37 patients transplanted beyond that date. In all donor-recipient pairs, histocompatibility was determined by serology for HLA-A and -B antigens and by high-resolution DNA typing for DRB1 antigen. High-resolution molecular typing of HLA class I antigens was employed in 20 of the 37 children transplanted more recently. Probability of both acute and chronic GVHD was comparable in the two groups of patients. In multivariate analysis, children transplanted before January 1998, those with T-lineage ALL and those experiencing grade II-IV acute GVHD had a higher relative risk of TRM at 6 months after transplantation. Relapse rate was unfavorably affected by a time interval between diagnosis and relapse <30 months. The 2-year probability of EFS for children transplanted before and after 1 January 1998 was 27% (10-44) and 58% (42-75), respectively (P = 0.02), this difference remaining significant in multivariate analysis. EFS of unrelated donor HSCT in children with ALL in second CR has improved in the last few years, mainly due to a decreased TRM. This information is of value for counseling of patients with relapsed ALL.

Antithymocyte globulin for graft-versus-host disease prophylaxis in transplants from unrelated donors: 2 randomized studies from Gruppo Italiano Trapianti Midollo Osseo (GITMO).

One hundred nine patients with hematologic malignancies, undergoing bone marrow transplants (BMT) from unrelated donors, were randomized in 2 consecutive trials to receive or not to receive antithymocyte globulin (ATG) in the conditioning regimen, as follows: (A) 54 patients (median age, 28 years; 39% with advanced disease) were randomized to no ATG (n = 25) versus 7.5 mg/kg rabbit ATG (Thymoglobulin; Sangstat, Lyon, France) (n = 29); (B) 55 patients (median age, 31 years, 71% with advanced disease) were randomized to no ATG (n = 28) versus 15 mg/kg rabbit ATG (n = 27). Grade III-IV graft-versus-host disease (GVHD) was diagnosed in 36% versus 41% (P =.8) in the first and in 50% versus 11% (P =.001) in the second trial. Transplant-related mortality (TRM), relapse, and actuarial 3-year survival rates were comparable in both trials. In fact, despite the reduction of GVHD in the second trial, a higher risk for lethal infections (30% vs 7%; P =.02) was seen in the arm given 15 mg/kg ATG. Extensive chronic GVHD developed overall more frequently in patients given no ATG (62% vs 39%; P =.04), as confirmed by multivariate analysis (P =.03). Time to 50 x 10(9)/L platelets was comparable in the first trial (21 vs 24 days; P =.3) and delayed in the ATG arm in the second trial (23 vs 38 days; P =.02). These trials suggest that (1) 15 mg/kg ATG before BMT significantly reduces the risk for grade III-IV acute GVHD, (2) this does not translate to a reduction in TRM because of the increased risk for infections, and (3) though survival is unchanged, extensive chronic GVHD is significantly reduced in patients receiving ATG.