Immunogenicity and Tolerance of BNT162b2 mRNA Vaccine in Allogeneic Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (ASCT) induces acquired immunodeficiency, potentially altering vaccine response. Herein, we aimed to explore the clinical tolerance and the humoral and cellular immune responses following anti-SARS-CoV-2 vaccination in ASCT recipients. METHODS: A prospective, non-randomized, controlled study that involved 43 ASCT subjects and 31 healthy controls. Humoral response was investigated using the Elecsys® test anti-SARS-CoV-2. Cellular response was assessed using the QFN® SARS-CoV-2 test. The lymphocyte cytokine profile was tested using the LEGENDplex™ HU Th Cytokine Panel Kit (12-plex). RESULTS: Adverse effects (AE) were observed in 69% of patients, encompassing pain at the injection site, fever, asthenia, or headaches. Controls presented more side effects like pain in the injection site and asthenia with no difference in the overall AE frequency. Both groups exhibited robust humoral and cellular responses. Only the vaccine transplant delay impacted the humoral response alongside a previous SARS-CoV-2 infection. Noteworthily, controls displayed a Th1 cytokine profile, while patients showed a mixed Th1/Th2 profile. CONCLUSIONS: Pfizer-BioNTech® anti-SARS-CoV-2 vaccination is well tolerated in ASCT patients, inducing robust humoral and cellular responses. Further exploration is warranted to understand the impact of a mixed cytokine profile in ASCT patients.

Coagulase negative Staphylococcus bacteremia in hematopoietic stem cell transplant recipients: Clinical features and molecular characterization.

The purpose of our study was to investigate the epidemiology of coagulase negative staphylococci (CoNS) responsible for bacteremia in hematopoietic stem cell transplant (HSCT) recipients and to determine the prevalence and the genetic background of methicillin resistance. The prevalence of CoNS bacteremia was 7.4% (54/728), higher in allograft (10.7%) than in autograft (4.7%) recipients. A sepsis or a septic shock were observed in 9% of cases. No deaths were attributable to CoNS bacteremia. The methicillin resistance rate was 81%. All MR-CoNS, harbored mecA gene and 90% were typeable with SCCmec typing using PCR amplification. The SCCmec type IV was the most frequent (44%). Clonal dissemination of MR- Staphylococcus epidermidis strains was limited. Our study showed a low prevalence and favorable outcome of CoNS bacteremia in HSCT recipients with limited clonal diffusion. However, they were associated with a significant rate of severe infections and a high rate of methicillin resistance, mediated by SCCmec IV element in most cases.

RORC overexpression as a sign of Th17 lymphocytes accumulation in multiple myeloma bone marrow.

The role of the bone marrow microenvironment in supporting the proliferation and survival of the abnormal plasma cells in multiple myeloma (MM) is well established. Such microenvironment is rich of cytokines like IL-6, TGF-ß, IL-1 and IL-23 which are known to promote the differentiation of Th17 lymphocytes, a T helper subpopulation. Th17 cells secrete IL-17, a cytokine involved in the pathophysiology of several auto-immune diseases. Yet, its involvement in cancers remains unclear. Herein, we aimed to try to understand the role of Th17 lymphocytes in multiple myeloma. Bone marrow samples were prospectively collected from 29 MM patients and 23 healthy bone marrow donors for allograft. Mononuclear bone marrow cells were isolated by Ficoll-Hypaque gradient and CD138+ plasma cells were depleted using magnetic beads. The quantification of Th17 cells was performed by flow cytometry in the CD138 negative cells. The mRNA expression of IL17 and RORc was quantified using real time PCR in the same subset. The mRNA expression of IL17R was analyzed in plasma cells (CD138+ cells). Data obtained from patients and healthy donors were compared by both non-parametric Mann-Whitney U test and Spearman test. A significant increase of IL17 and RORC mRNA expression was found in the bone marrow microenvironment of MM patients compared to healthy donors. Th17 cells were also increased in the bone marrow of MM patients compared to healthy donors. Interestingly, the mRNA expression of IL17R was significantly decreased in MM patients. Yet, no correlation was found between the gene expression IL17, RORC and IL17R and the bone marrow infiltration or the stage of the disease. Collectively, our results suggest the involvement of Th17 cells in the pathophysiology of MM. Such data further support the use of anti-IL-17 antibodies as a therapeutic approach in MM.

Once-a-day fractionated total-body irradiation: A regimen tailored to local logistics in allogeneic stem cell transplantation for acute lymphoblastic leukemia.

AIM: The objective of the study was to estimate the cumulative incidence (CI) of relapse, relapse-free survival (RFS) and overall survival (OS) in ALL patients after a once-a-day fractionated TBI (F-TBI) regimen with 9.9 Gy. The secondary objectives were evaluation of short and long-term toxicity and non-relapse mortality (NRM). BACKGROUND: Total body irradiation (TBI), as a part of the conditioning regimen before allogeneic stem cell transplantation (ASCT) for acute lymphoblastic leukemia (ALL), allows disease control by eradicating residual blast cells in the transplant recipient. MATERIALS AND METHODS: Retrospective study conducted in patients with ALL who received between March 2003 and December 2013 a conditioning regimen with F-TBI and chemotherapy. Irradiation was delivered with 3.3 Gy once-a-day for three consecutive days. RESULTS: Eighty-seven patients were included. The median age was 19 years (range: 5-49 years). The 3-year CI of relapse was 30%. The estimated 3-year RFS and OS were 54% and 58%, respectively. Cumulative incidence of acute graft-versus-host disease (aGVHD) grade II-IV and chronic GVHD (cGVHD) was 31% and 40%, respectively. Interstitial pneumonitis was observed in 2 patients. The 3-year CI of NRM was 16%. In multivariate analysis, cGVHD was associated with a lower CI of relapse (RR = 0.26, 95% CI: 0.07-0.95, p = 0.04). High-risk cytogenetics was associated with a lower RFS (RR = 2, 95 CI: 1.04-3.84, p = 0.03). Grade II-IV aGVHD was an independent predictor of higher CI of NRM (RR = 6.7, 95% CI: 1.4-31.7, p = 0.02). CONCLUSIONS: Once-a-day F-TBI regimen is effective, safe and practical in patients who underwent ASCT for ALL.

Filgrastim following HLA-Identical Allogeneic Bone Marrow Transplantation: Long-Term Outcomes of a Randomized Trial.

Human recombinant granulocyte colony stimulating factor reduces the duration of neutropenia following HLA-identical allogeneic bone marrow transplantation. However, its use remains controversial due to the risk of increasing the incidence of acute graft-versus-host disease (GVHD) and slower platelet recovery. To clarify these risks, we conducted a prospective randomized placebo-controlled trial of filgrastim 5 µg/kg/day i.v. from day 7 post-transplant until neutrophil recovery in 145 consecutive adults undergoing HLA-identical allogeneic bone marrow transplantation, with cyclosporine and methotrexate as GVHD prophylaxis. The primary endpoint was the incidence of acute GVHD; hematological recovery, nonrelapse mortality, and post-transplant complications were secondary endpoints. Filgrastim had no significant effect on the incidence of acute GVHD, platelet recovery, platelet transfusion requirements, chronic GVHD, or survival. Filgrastim accelerated granulocyte recovery significantly (with absolute neutrophil counts >.5 × 109/L achieved after a median of 16 days versus 23 days for placebo; P < .0001), and reduced both early nonrelapse mortality (2.9% versus 10.5%; P = .042) and the duration of i.v. antibiotic therapy (18 days versus 26 days; P = .001) and hospitalization (27 versus 34 days; P = .017). In conclusion, in this setting, filgrastim reduced significantly the duration of neutropenia, i.v. antibiotic therapy, hospitalization, and early nonrelapse mortality, without increasing the risk of acute and chronic GVHD or relapse, or delaying platelet recovery.

Extended spectrum beta-lactamase-producing Enterobacteriaceae infections in hematopoietic stem cell transplant recipients: Epidemiology and molecular characterization.

BACKGROUND: Extended spectrum ß-lactamase-producing Enterobacteriaceae (ESBL-E) create a therapeutic challenge and have high potential for dissemination. The purpose of our study was to investigate the epidemiology of these infections in hematopoietic stem cell transplant (HSCT) recipients and to determine the genes encoding ESBL. MATERIAL/METHODS: This retrospective study comprised adult patients hospitalized at the National Bone Marrow Transplant Center (NBMTC) and infected with ESBL-E post-HSCT between January 2006 and December 2016. The search for the ESBL and carbapenemase genes was performed by polymerase chain reaction (PCR) amplification. Molecular typing was performed by pulsed field gel electrophoresis (PFGE) after digestion with XbaI. RESULTS: Forty ESBL-E were responsible for infections in 34 HSCT recipients (3.3% of total HSCT recipients). Prior hospital stay, prior antibiotic therapy and prior colonization with ESBL-E were reported in 62.5%, 70% and 50% of the infectious episodes, respectively. The initial antibiotic treatment was appropriate in 67.7% of cases. Imipenem was the most prescribed antibiotic (64.5%). The mortality rate due to ESBL-E infection was 8.8%. The ESBL-E, isolated mainly from blood cultures (40%), belonged mostly to K. pneumoniae (n=19) and E. coli (n=17). Associated antibiotic resistance rates were 17.5% for ertapenem, 85% for ciprofloxacin and 30% for amikacin. The predominant gene encoding ESBL was blaCTX-M (55%). Among the seven carbapenem-resistant strains, four had the blaOXA-48 gene and two the blaKPC gene. There was no clonal relationship between the strains. CONCLUSION: There was low prevalence of ESBL-E infections in HSCT recipients in our center, with no epidemic distribution but non-negligible mortality rate.

Plasmodium falciparum infection transmitted by transfusion: A cause of hemophagocytic syndrome after bone marrow tranplantation in a non-endemic country.

A 27-year-old man with severe aplastic anemia underwent bone marrow transplantation from his HLA identical brother in July 2016. Conditioning included ATGAM 30 mg/kg for 3 days and Cyclophosphamide 50 mg/kg for 4 days. The patient received several platelet and red blood cell transfusions before and after the conditioning. The patient received broad spectrum antibiotics and caspofungin because persistant febrile neutropenia without bacteriological or mycological documentation. Hemophagocytic syndrome was diagnosed on day +12. Steroids at 1 mg/kg were started on day +12. Fever resolved the same day but resumed 3 days later associated to intravascular hemolysis with no schizocytes on blood smears and negative DAT. Thick blood film smears performed on day +26 revealed Plasmodium falciparum parasites (parasitemia = 20%). Except the level of parasitemia, there were no signs of gravity. Quinine was started on day 26 at a loading dose of 15 mg/kg followed by 8 mg/kg three times a day for 20 doses. Fever vanished after 2 days. Parasitemia cleared in 3 days and remained negative thereafter. Investigations revealed that the patient was transfused by a red cell unit harvested in a voluntary donor native of a malaria endemic country. PCR for P. falciparum performed in this donor in the frame of investigations was positive. The patient is alive with a normal blood count 1 year after BMT.

Abnormal repression of SHP-1, SHP-2 and SOCS-1 transcription sustains the activation of the JAK/STAT3 pathway and the progression of the disease in multiple myeloma.

Sustained activation of JAK/STAT3 signaling pathway is classically described in Multiple Myeloma (MM). One explanation could be the silencing of the JAK/STAT suppressor genes, through the hypermethylation of SHP-1 and SOCS-1, previously demonstrated in MM cell lines or in whole bone marrow aspirates. The link between such suppressor gene silencing and the degree of bone marrow invasion or the treatment response has not been evaluated in depth. Using real-time RT-PCR, we studied the expression profile of three JAK/STAT suppressor genes: SHP-1, SHP-2 and SOCS-1 in plasma cells freshly isolated from the bone marrows of MM patients and healthy controls. Our data demonstrated an abnormal repression of such genes in malignant plasma cells and revealed a significant correlation between such defects and the sustained activation of the JAK/STAT3 pathway during MM. The repressed expression of SHP-1 and SHP-2 correlated significantly with a high initial degree of bone marrow infiltration but was, unexpectedly, associated with a better response to the induction therapy. Collectively, our data provide new evidences that substantiate the contribution of JAK/STAT suppressor genes in the pathogenesis of MM. They also highlight the possibility that the decreased gene expression of SHP-1 and SHP-2 could be of interest as a new predictive factor of a favorable treatment response, and suggest new potential mechanisms of action of the therapeutic molecules. Whether such defect helps the progression of the disease from monoclonal gammopathy of unknown significance to MM remains, however, to be determined.

Hematopoietic stem cell transplantation in the Eastern Mediterranean Region (EMRO) 2011-2012: A comprehensive report on behalf of the Eastern Mediterranean Blood and Marrow Transplantation group (EMBMT).

OBJECTIVE/BACKGROUND: The Eastern Mediterranean Blood and Marrow Transplantation (EMBMT) group has accumulated over 31 years of data and experience in hematopoietic stem cell transplantation (HSCT), particularly in hemoglobinopathies, severe aplastic anemia, inherited metabolic and immune disorders, in addition to a wide array of hematologic malignancies unique to this region. A regional update in current HSCT trends is highly warranted. We studied the trends of HSCT activities in World Health Organization-Eastern Mediterranean (EMRO) region, surveyed by the EMBMT, between 2011 and 2012. METHODS: Retrospective analysis of the survey data mainly of cumulative number of transplants, types of transplants (autologous vs. allogeneic), types of conditioning such as myeloablative versus reduced intensity was conducted. Also, trends in leukemias, hemoglobinopathies, severe aplastic anemia, inherited bone marrow failure syndromes, amongst others were analyzed. RESULTS: Twenty-one teams from nine EMRO countries reported their data (100% return rate) to the EMBMT for the years 2011-2012, with a total of 3,546 first HSCT (1,670 in 2011; 1,876 in 2012). Allogeneic HSCT (allo-HSCT) represented the majority (62%) in both years. The main indications for allo-HSCT were acute leukemias (988; 46%), bone marrow failure syndromes (421, 20%), hemoglobinopathies (242; 11%), and immune deficiencies (157; 7%). There was a progressive increase in the proportions of chronic myeloid leukemia cases transplanted beyond first chronic phase (37 [7%] of all chronic myeloid leukemia cases in 2011 vs. 39 [29%] in 2012). The main indications for autologous transplants were multiple myeloma/plasma cell disorders (510; 39%), Hodgkin lymphoma (311; 24%), non-Hodgkin lymphoma (259; 20%), and solid tumors (163; 12%). Reduced intensity conditioning continued to show a progressive decrease over years (9.5% in 2011 vs. 7.9% in 2012), yet remained relatively low compared with contemporary practices in Europe published by EBMT. The vast majority (91%) of allo-HSCT source was from sibling donors with continued dominance of peripheral blood (64%) followed by bone marrow (33%).While umbilical cord blood transplants increased to 4% of allo-HSCT, matched unrelated donor remained underutilized and there was no haplo-identical transplant reported. Large centers with >50 HSCT/year, showed a continued increase in the total number of allo-HSCT over the past 2years that may be related to capacity building issues and require further studies. CONCLUSION: There is a discernable increase of HSCT rate in the EMRO region with a significant expansion in utilization of cord blood transplants and allogeneic peripheral blood-HSCT as a valuable source. However, further research of outcome data and the development of regional donor banks (cord blood and matched unrelated donors) may help to facilitate future planning to satisfy the escalating regional needs and augment collaboration within the EMBMT and globally.

[Does multiple myeloma response to induction therapy depend on plasma cell IL6 receptor gene expression?]. / L'expression de l'IL6-r par les plasmocytes influe-t-elle la réponse au traitement d'induction au cours du myélome multiple ?

BACKGROUND: Interleukine 6 (IL-6) is the most important cytokine involved in malignant plasma cells growth and survival. AIM: To analyse bone marrow plasma cells IL6 receptor gene expression in both multiple myeloma patients at diagnosis and healthy bone marrow donors. METHODS: Clinical and biological patients' features and responses to Dexamethasone-Thalidomide induction therapy were gathered. 47 patients and 16 case controls were analyzed: Bone marrow plasma cells were isolated; and IL6 receptor gene expression was quantified using Taqman quantitative PCr technology and 2-ΔCT formula. RESULTS: Quantitative and qualitative IL6 receptor gene expression were negatively correlated with the degree of response to therapy (p= 0.02). In this study, plasma cells IL6 receptor gene expression seems to be decisive in predicting the response to treatment. CONCLUSION: Understanding the mechanisms involved in plasma cells IL6 receptor gene expression may offer a better appreciation of the physiopathologic and anti-oncogenic ways of drug resistance in multiple myeloma and consequently the discovery of new specific drugs.

Autoimmune polyglandular syndrome type II after bone marrow transplant: real transfer or acceleration of a programmed disease?

We report a case of autoimmune polyglandular syndrome type II that developed in an 11-year-old boy with homozygous sickle cell disease after allogeneic bone marrow transplant; the donor was his father, who was human leukocyte antigen identical and had vitiligo. On day 24 after transplant, the patient developed grade 1 acute graft-versus-host disease, which was controlled over a period of 3 months with corticosteroid-induced immunosuppression. Full donor engraftment was documented on day 31 after transplant, and this was further confirmed on days 59, 231, 321, 472, 549, and 720. Three months after transplant, the recipient developed adrenal insufficiency, and at 13 months, he developed vitiligo. Seventeen months after transplant, autoimmune thyroid disease, positive for thyroid peroxidase and thyroglobulin autoantibodies, was diagnosed. At the same time, we identified adrenal insufficiency in the donor. We analyzed a serum sample from the recipient for autoantibody markers for type 1 autoimmune diabetes mellitus. The sample was positive for antiglutamic acid decarboxylase. Antibody against 21-hydroxylase enzyme was also found (261 U/mL; normal value, < 1 U/mL). We conclude that the recipient developed autoimmune polyglandular syndrome type II after bone marrow transplant from his father, who was probably affected by the same syndrome.

Do FY antigens act as minor histocompatibility antigens in the graft-versus-host disease paradigm after human leukocyte antigen-identical sibling hematopoietic stem cell transplantation?

FY antigens are candidate minor histocompatibility antigens relevant to renal allograft rejection, but no data have been reported about their role in graft-versus-host disease (GVHD) incidence after human leukocyte antigen (HLA)-identical siblings hematopoietic stem cell transplantation (HSCT). The aim of this study was to examine the effect of donor/recipient disparity at FY antigens on the incidence of GVHD in Tunisian patients receiving an HLA-identical HSCT. This work enrolled 105 Tunisian pairs of recipients and their HLA-identical sibling donors of HSCs. FY genotyping was performed with the polymerase chain reaction-sequence-specific primer method and donor/recipient disparity for these antigens was analyzed at two levels: incompatibility and nonidentity. The case-control analyses showed no significant correlation between FY disparity and the incidence of either acute or chronic GVHD. Sample size calculation showed that 572 cases and 1716 controls would be necessary to be able to detect a significant association with 80% power and two-sided type I error level of 5% (α=0.05). The lack of association in the studied cohort may be explained by the low immunogenicity of FY antigens in HSCT context, compared with other antigens such as HA-1 and CD31.

Hematopoietic stem cell transplantation in the Eastern Mediterranean Region (EMRO) 2008-2009: report on behalf of the Eastern Mediterranean Bone Marrow Transplantation (EMBMT) Group.

BACKGROUND: The Eastern Mediterranean Bone Marrow Transplantation (EMBMT) Group has accumulated over 25 years of data and experience in hematopoietic stem cell transplantation (HSCT), most particularly in hemoglobinopathies, severe aplastic anemia (SAA), and inherited metabolic and immune disorders, in addition to hematologic malignancies peculiar to the region and where recent updates in trends in activities are warranted. OBJECTIVES: To study trends in HSCT activities in the World Health Organization-Eastern Mediterranean (EM) region surveyed by EMBMT between 2008 and 2009. STUDY DESIGN: Retrospective analysis of the survey data, mainly of the cumulative number of transplants, types of transplants (autologous vs. allogeneic), types of conditioning as myeloablative (MAC) vs. reduced intensity conditioning (RIC) and trends in leukemias, hemoglobinopathies, SAA, inherited bone marrow failure syndromes amongst others. RESULTS AND DISCUSSION: Fourteen teams from ten Eastern Mediterranean Region Organization (EMRO) countries reported their data (100% return rate) to the EMBMT for the years 2008-2009 with a total of 2608 first HSCT (1286 in 2008; 1322 in 2009). Allogeneic HSCT represented the majority (63%) in both years. The main indications for allogeneic HSCT were acute leukemias (732; 44%), bone marrow failure syndromes (331, 20%), hemoglobinopathies (255; 15%) and immune deficiencies (90; 5%). There was a progressive increase in the proportions of chronic myeloid leukemia (CML) cases transplanted beyond the first chronic phase (3; 7% of all CML cases in 2008 vs 13; 29% in 2009). The main indications for autologous transplants were plasma cell disorders (345; 36%) Hodgkin disease (256; 27%), non-Hodgkin lymphoma (207; 22%) and solid tumors (83; 9%). RIC continued to show a progressive increase over the years (7% in 2007, 11% in 2008 and 13% in 2009), yet remained relatively low compared to contemporary practices in Europe published by EBMT. The vast majority (95%) of allo-HSCT sources were from sibling donors with a continued dominance of peripheral blood (PB) (1076; 63%), while cord blood transplant (CBT) increased to 83 (5% of allo-HSCT), matched unrelated donor (MUD) remained underutilized (1; 0%) and there were no haploidentical transplants reported. Large centers with >50 HSCT/year showed a plateau of the total number of allo-HSCT over the last 5 years that may be related to capacity issues and needs further study. CONCLUSIONS AND RECOMMENDATIONS: There is an overall increased rate of HSCT in the EMRO region with a significant increase in utilization of CBT and allogeneic PB-HSCT as a valuable source. However, further research on outcome data and development of regional donor banks (CB and MUD) may help facilitate future planning to satisfy the regional needs and increase collaboration within the group and globally.

Evidence that erythrocyte DARC-positive phenotype can affect the GVHD occurrence after HLA-identical sibling HSCT.

Chemokine receptors are very important players in the pathogenesis of GVHD. The aim of this study is to test the hypothesis that the lack of expression of the DARC receptor on erythrocytes can affect the GVHD incidence. A total of 105 recipients and their 105 respective sibling donors of HSCs were enrolled in this study. All patients were evaluated for acute and chronic GVHD. The DARC genotyping assay was performed using the SSP-PCR method. The case-control analyses showed that the donor DARC 146G allele and T(-46)G(146) haplotype, coding for the FY2 version of DARC, are very significant in the GVHD paradigm because they are associated with the incidence of acute effects of this outcome in recipients (p=0.007, χ²=7.200). It seems that this version of DARC receptor is a powerful facilitator of chemokine transcytosis and subsequently leukocyte migration into GVHD target organs.

Investigation of the effect of donor platelet endothelial cell adhesion molecule 1 polymorphism on the graft-vs.-host disease occurrence in Tunisian recipients of hematopoietic stem cells.

OBJECTIVE: The aim of this study is to examine the effect of donor PECAM-1 alleles and haplotypes for the SNPs L98V, S536N, and R643G on the occurrence of GVHD in Tunisian recipients of HSCs. DESIGN AND METHODS: This study enrolled 102 patients and their 102 respective HLA-identical sibling donors of HSCs. The PECAM-1 SNPs genotyping assay was performed using sets of sequence specific primers (SSP-PCR). RESULTS: The single marker association analysis showed that the L98 allele, in a recessive genetic model, may be a potential risk factor only for acute GVHD (p=0.036, OR=2.580, 95% C.I. = 1.053-6.326). However, the haplotype analysis showed a lack of association between donor's PECAM-1 SNPs and GVHD incidence in recipient. CONCLUSION: The homozygosity state for donor PECAM-1L98 allele may be a significant risk factor for acute GVHD. This is probably due to its action on the function of donor leukocytes especially during the extravasation process.

Effect of donor CTLA-4 alleles and haplotypes on graft-versus-host disease occurrence in Tunisian patients receiving a human leukocyte antigen-identical sibling hematopoietic stem cell transplant.

The CTLA-4 genetic variation, such as single nucleotide polymorphisms (SNPs) may be critical and can affect the functional activity of cells that initiate the graft-versus-host disease (GVHD) effects. The aim of this study is to examine the effect of donor CTLA-4 alleles and haplotypes for the -318C>T and the 49A>G polymorphisms on the occurrence of GVHD in Tunisians recipients of HSCs. A total of 112 patients and their 112 respective sibling donors of HSCs were enrolled in this study. All patients had either grades 0-I or grades II-IV acute GVHD, or chronic GVHD. The SNPs genotyping assay was performed using sets of sequence specific primers (SSP-PCR). The single marker association analysis showed that the 49G allele, in a genetic recessive model, may be a potential risk factor only for the chronic GVHD (p = 0.032, odds ratio [OR] = 2.58, 95% confidence interval = 1.05-6.32). The haplotypes analyses showed that the CTLA-4 -318C49G nucleotide combination is significantly associated with the incidence of chronic GVHD (p = 0.043, χ² = 3.27). Donor CTLA-4 -318C49G haplotype may be a significant risk factor for developing chronic GVHD after allo-stem cell transplantation. We suppose that donor T cells expressing this haplotype in a homozygous state have higher proliferation than those expressing other haplotypes, especially after recognition of the recipient's minor histocompatibility antigens.

Acute graft-vs.-host disease correlates with the disparity for the PECAM-1 S536N polymorphism only in the HLA-B44-like positive Tunisian recipients of HSCs.

GVHD is the major cause of mortality after HLA-identical HSCT. Such complication has been widely linked to donor/recipient disparity for minor histocompatibility antigens (MiHAgs). PECAM-1 is one of potential human MiHAgs but its effect on the GVHD occurrence remains not clear. In order to examine such association in the Tunisian cohort of HSCs recipients, we performed a retrospective study on patients who undergone HLA-identical HSCT between 2000 and 2009. Genotyping of the three selected PECAM-1 polymorphisms (rs668, rs12953 and rs1131012) was performed with SSP-PCR method. Univariate analyses showed that grades II-IV acute GVHD were considerably linked to the non-identity for rs12953 only in HLA-B44-like positive patients (p=0.010, OR=10.000). Multivariate analysis for chronic GVHD showed that this outcome may be affected only by the adulthood and the conditioning regimen. Our findings support the previously reported data suggesting a significant association between the PECAM-1 disparity and the risk of acute GVHD.

Switch from beta-thalassemia major to beta-thalassemia intermedia after secondary graft failure.

In this article, we report a switch of beta-thalassemia major to intermedia beta-thalassemia after allogeneic bone marrow transplant of a 6-year-old girl from her HLA-matched brother. After stable mixed chimerism, the patient had a secondary graft rejection and returned to total recipient chimerism as assessed by real-time polymerase chain reaction assay. Nonetheless, with a medium hemoglobin rate of 89 g/L, she did not need further transfusions for 60 months after rejection. We conclude that complete loss of donor cells after bone marrow transplant for beta-thalassemia major is compatible with a stable clinical state, probably due to a gamma-globin gene demethylation that enhances gamma-globin chain production and further allows constitution of a fetal hemoglobin rate compatible with free transfusion survival.

Mismatch for the minor histocompatibility antigen HA-2 and GVHD occurrence in HLA-A*0201-positive Tunisian recipients of HSCs.

Graft-versus-Host disease (GVHD) has been widely linked to immunogenetic causes such as disparity between the recipient and its HLA geno-identical donor for some Non-HLA antigens called minor histocompatibility antigens (MiHAgs). HA-2 is one of potential human MiHAgs but its effect on the GVHD occurrence remains not clear. In order to examine such association in the Tunisian cohort of HSCs recipients, we performed a retrospective study on patients who received an HLA-identical HSCT between 2000 and 2009. The study was performed on 60 HLA-A2-positive patients who had received a haematopoietic stem cell transplant from an HLA-identical sibling. All patients received cyclosporine A and/or methotrexate for GVHD prophylaxis. HA-2 genotyping assay was performed with SSP-PCR method and HLA-A*0201 positive samples were identified mainly with Luminex HLA-Typing method. Luminex HLA-Typing assay showed that only 53 cases were positives for the HLA-A*0201 allele. Among these cases, only 3 pairs were mismatched for the MiHAg HA-2. Acute GVHD occurred in 01 HA-2-mismatched pair while chronic GVHD was detected in 02 disparate couples. Univariate and multivariate analyses showed that MiHAg HA-2 disparity does not have any significant effect on the occurrence of either acute or chronic GVHD. This last one appeared to be correlated only with the age of patient (adulthood) (p: 0.011, OR: 22.092). Our findings support the previously reported data denying the influence of the HA-2 disparity on the GVHD occurrence after HSCT.