Excellent Engraftment and Reduced Acute and Chronic Graft Versus Host Disease (GVHD) in ATG-Refractory Severe Aplastic Anemia (SAA) Following Transplantation of a PBSC Allograft Containing CD34+ Selected Cells Combined with Non-Mobilized Donor T-Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3882-3882
Author(s):  
Enkhtsetseg Purev ◽  
Xin Tian ◽  
Jeremy M Pantin ◽  
Robert N Reger ◽  
Lisa Cook ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Bone Marrow Failure ◽  
Chronic Gvhd ◽  
Historical Cohort ◽  
Post Transplant ◽  
Bone Marrow Failure Syndromes ◽  
Cell Engraftment ◽  
Gvhd Prophylaxis

Abstract Introduction: The risk of graft-rejection after allogeneic hematopoietic cell transplantation using bone marrow and conventional cyclophosphamide-based conditioning is increased in HLA allo-immunized and heavily transfused patients with bone marrow failure syndromes. Recently, we showed that fludarabine-based peripheral blood stem cells transplantation (PBSCT) overcomes the risk of graft-failure in patients with SAA who have failed immunosuppressive therapy (IST). However, this approach was complicated by a high incidence of acute and chronic GVHD. Multivariate analysis showed rapid donor T-cell engraftment (defined as >= 95% donor T-cell chimerism by post-transplant day 30) significantly increased the risk of cGVHD. Based on these data, we developed a novel transplant approach in which a G-CSF mobilized PBSC allograft that was T-cell depleted and CD34+ selected was co-infused with a bone marrow transplant (BMT)-equivalent dose of non-mobilized donor T-cells to facilitate donor engraftment and reduce GVHD by delaying the speed of donor T-cell engraftment. Method: Patients with transfusion-dependent SAA, refractory to conventional IST, underwent allogeneic PBSCT following cyclophosphamide (60 mg/kg/d IV x 2 days), equine antithymocyte globulin (hATG; 40 mg/kg/d IV x 4 days), and fludarabine (25 mg/m2/d IV x 5 days) conditioning. On day 0, patients received a G-CSF mobilized PBSC allograft from an HLA identical sibling, containing CD34+ selected cells (MiltenyiCliniMACS system: target CD34+ cell dose 8 x 106 cells/kg and target T-cell dose < 3 x 105 cells/kg) combined with 2 x 107CD3+ T-cells/kg that had been collected by apheresis and cryopreserved from the same donor prior to G-CSF mobilization. CSA and mini-dose MTX (5 mg/m2 IV on days 1, 3, 6) were used as GVHD prophylaxis. Transplant outcomes were compared to our historical cohort of patients (n=56) with SAA and other bone marrow failure syndromes who received a T-cell replete PBSC from an HLA matched donor following the identical conditioning and GVHD prophylaxis regimens. Results: 11 patients with SAA were transplanted. Patients were heavily transfused and highly allo-immunized; the pre-transplant serum ferritin level was markedly elevated at a median 3003 µg/L (range 286 to 13928 µg/L) and 7 patients (64%) were HLA allo-immunized with a median 21% (HLA class I) and 31% (HLA class II) panel-reactive antibodies. All 11 patients (100%) engrafted. The median time to neutrophil and platelet recovery was 14 (range 12 to 23) and 18 (range 14 to 321) days respectively. All patients achieved full and sustained donor T-cell chimerism and myeloid chimerism, which occurred at a median 45 and 15 days post-transplant, respectively. Among those at risk, 6/7 (86%) developed CMV reactivation. EBV reactivation occurred in all cases, including 5 who received preemptive treatment with rituximab. At a median follow-up of 2 years, only 1 patient (9%) has developed acute and another (9%) developed cGVHD (limited, skin). Neither corticosteroid-refractory aGVHD nor extensive cGVHD occurred. Long-term survival was excellent; 10 of 11 patients (91%) survived to day 200; at a median follow-up of 2.7 years, 9/11 (80%) survive. One patient died on day 46 from Klebsiella Pneumoniae carbapenemase bacteremia, which predated the transplant, and another died 18 months post-transplant from bacterial pneumonia. Compared to our historical cohort of marrow failure patients who received a T-cell replete PBSC allograft, patients receiving CD34+ selected cells combined with non-mobilized T-cells (partially T cell depleted PBSC) had similar survival (80% vs 87%;p=0.5), a delay in the time to achieving full donor T-cell chimerism (45 days vs 30 days; p=0.046) and dramatic reductions in both acute grade II-IV GVHD (9% vs 52%; p=0.017) and cGVHD (1 year incidence 9% vs 63%; p=0.002). Conclusion: In SAA, transplantation of a PBSC allograft containing high numbers of CD34+ selected cells co-infused with a BMT-equivalent dose of non-mobilized T-cells results in excellent engraftment and reduces acute and chronic GVHD by delaying the speed of donor T-cell engraftment. Figure: Figure:. Disclosures Townsley: GSK: Research Funding.

scholarly journals Outcome of alloanergized haploidentical bone marrow transplantation after ex vivo costimulatory blockade: results of 2 phase 1 studies

Blood ◽  
2008 ◽  
Vol 112 (6) ◽  
pp. 2232-2241 ◽  
Author(s):  
Jeff K. Davies ◽  
John G. Gribben ◽  
Lisa L. Brennan ◽  
Dongin Yuk ◽  
Lee M. Nadler ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Bone Marrow Transplantation ◽  
T Cell ◽  
Marrow Transplantation ◽  
Viral Infections ◽  
Ex Vivo ◽  
Chronic Gvhd ◽  
Costimulatory Blockade ◽  
Donor T Cells

AbstractWe report the outcomes of 24 patients with high-risk hematologic malignancies or bone marrow failure (BMF) who received haploidentical bone marrow transplantation (BMT) after ex vivo induction of alloantigen-specific anergy in donor T cells by allostimulation in the presence of costimulatory blockade. Ninety-five percent of evaluable patients engrafted and achieved full donor chimerism. Despite receiving a median T-cell dose of 29 ×106/kg, only 5 of 21 evaluable patients developed grade C (n = 4) or D (n = 1) acute graft-versus-host disease (GVHD), with only one attributable death. Twelve patients died from treatment-related mortality (TRM). Patients reconstituted T-cell subsets and immunoglobulin levels rapidly with evidence of in vivo expansion of pathogen-specific T cells in the early posttransplantation period. Five patients reactivated cytomegalovirus (CMV), only one of whom required extended antiviral treatment. No deaths were attributable to CMV or other viral infections. Only 1 of 12 evaluable patients developed chronic GVHD. Eight patients survive disease-free with normal performance scores (median follow-up, 7 years). Thus, despite significant early TRM, ex vivo alloanergization can support administration of large numbers of haploidentical donor T cells, resulting in rapid immune reconstitution with very few viral infections. Surviving patients have excellent performance status and a low rate of chronic GVHD.

scholarly journals STAT3 mutations indicate the presence of subclinical T-cell clones in a subset of aplastic anemia and myelodysplastic syndrome patients

Blood ◽  
2013 ◽  
Vol 122 (14) ◽  
pp. 2453-2459 ◽  
Author(s):  
Andres Jerez ◽  
Michael J. Clemente ◽  
Hideki Makishima ◽  
Hanna Rajala ◽  
Ines Gómez-Seguí ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Myelodysplastic Syndrome ◽  
Aplastic Anemia ◽  
Somatic Mutation ◽  
Bone Marrow Failure ◽  
Cell Clones ◽  
Key Points ◽  
Stat3 Mutations

Key PointsSTAT3+ T cells are found not only in detected concomitant LGL-BMFs, but in cases in which an LGL expansion was not suspected. Transformation via acquisition of a somatic mutation in T cells may be a mechanism of immune, mainly hypoplastic, bone marrow failure.

SAP (SH2D1A), the Immunomodulator Deficient in X-Linked Lymphoproliferative Syndrome (XLP), Is Profoundly Decreased in Aplastic Anemia: An Immunologic Link between Constitutional and Acquired Bone Marrow Failure.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1141-1141
Author(s):  
Elena E. Solomou ◽  
Valeria Visconte ◽  
Federica Gibellini ◽  
Neal S. Young
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Aplastic Anemia ◽  
T Cell Activation ◽  
Cell Activation ◽  
Bone Marrow Failure ◽  
Protein Levels ◽  
Ifn Γ ◽  
Th1 Polarization

Abstract Ligation of the signaling lymphocyte activation molecule (SLAM), a member of the immunoglobulin superfamily expressed in T and B cells, results in T cell activation and Th1 cytokine production. SAP is a small cytoplasmic protein expressed in T- and NK cells that controls the activation signals mediated by SLAM. On T cell activation, SAP binds to Fyn kinase; Fyn is activated and phosphorylates tyrosine residues on SLAM; phosphorylation results in the formation of a complex that selectively down-regulates co-stimulatory signals in activated T cells, resulting in inhibition of IFN-γ production. Thus SAP acts as a natural suppressor of SLAM-mediated T cell activation, and, in the absence of SAP, T cells are constitutively activated and overproduce IFN-γ. Mutations in the SAP gene lead to abnormal T cell activation and enhanced Th1 cytokine production in mouse models and in humans: about half of patients with X-linked lympoproliferative disease (XLP) have functionally disabling SAP mutations. Acquired aplastic anemia (AA) is a bone marrow failure syndrome in which hematopoietic cell destruction is effected by cytotoxic T cells and type 1 cytokines. We have recently shown that T cells from patients with AA have increased protein levels of T-bet, resulting in IFN-γ overproduction (Solomou EE et al, Blood2006; 107:3983). IFN-γ inhibits hematopoietic stem cell proliferation and induces Fas-mediated apoptosis; stem cell depletion results in marrow hypoplasia and peripheral blood pancytopenia. We examined SAP expression as an explanation for aberrant T cell activation and extreme Th1 polarization. SAP protein expression on immunoblot was very low to absent in unstimulated T cells from 16 of 20 AA patients examined, as compared to normal levels of expression in equivalent numbers of healthy donors (p&lt;0.001). No significant differences were detected in Fyn and SLAM protein levels between AA and controls. SAP mRNA levels were also significantly decreased in T cells from those AA patients with low SAP protein levels, as determined by RT-PCR. Peripheral blood DNA samples from 18 patients with AA were analyzed for SAP mutations: three novel intronic mutations, not present in controls, were identified among 7 unrelated patients: one mutation was in the promoter region of SAP (position 106, C to T; 3 patients), and two mutations in the intron-exon junction between exons 1 and 2 (position 38975, C toT; 3 patients) and 3 and 4 (position 62771, C to A; 1 patient). IFN-γ, as measured by ELISA, in three patients with undetectable SAP protein levels was significantly increased compared to healthy controls (n=5, p&lt;0.001). Increased IFN-γ levels and Th1 polarization in AA can in part be explained by functional SAP deficiency. SAP-deficient T cells in AA would be unable to block co-stimulatory signals, leading to an activated T cell phenotype and ultimately hematopoietic cell destruction and bone marrow failure. The SAP-deficient phenotype in T cells from patients with aplastic anemia may be secondary to subtle genetic alteration in the gene’s regulation (abnormal promoter binding sites or epigenetic modulation due to mutations in introns) or as yet unidentified aberrant upstream pathways (Ets-1 and Ets-2, the transcription factors that regulate SAP expression).

Pentostatin Facilitates Fully MHC-Disparate Murine Mini-Transplantation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3539-3539
Author(s):  
Jacopo Mariotti ◽  
Kaitlyn Ryan ◽  
Paul Massey ◽  
Nicole Buxhoeveden ◽  
Jason Foley ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Suppression ◽  
Graft Rejection ◽  
Mixed Chimerism ◽  
Post Transplant

Abstract Abstract 3539 Poster Board III-476 Pentostatin has been utilized clinically in combination with irradiation for host conditioning prior to reduced-intensity allogeneic hematopoietic stem cell transplantation (allo-HSCT); however, murine models utilizing pentostatin to facilitate engraftment across fully MHC-disparate barriers have not been developed. To address this deficit in murine modeling, we first compared the immunosuppressive and immunodepleting effects of pentostatin (P) plus cyclophosphamide (C) to a regimen of fludarabine (F) plus (C) that we previously described. Cohorts of mice (n=5-10) received a three-day regimen consisting of P alone (1 mg/kg/d), F alone (100 mg/kg/d), C alone (50 mg/kg/d), or combination PC or FC. Combination PC or FC were each more effective at depleting and suppressing splenic T cells than either agent alone (depletion was quantified by flow cytometry; suppression was quantified by cytokine secretion after co-stimulation). The PC and FC regimens were similar in terms of yielding only modest myeloid suppression. However, the PC regimen was more potent in terms of depleting host CD4+ T cells (p<0.01) and CD8+ T cells (p<0.01), and suppressing their function (cytokine values are pg/ml/0.5×106 cells/ml; all comparisons p<0.05) with respect to capacity to secrete IFN-g (13±5 vs. 48±12), IL-2 (59±44 vs. 258±32), IL-4 (34±10 vs. 104±12), and IL-10 (15±3 vs. 34±5). Next, we evaluated whether T cells harvested from PC-treated and FC-treated hosts were also differentially immune suppressed in terms of capacity to mediate an alloreactive host-versus-graft rejection response (HVGR) in vivo when transferred to a secondary host. BALB/c hosts were lethally irradiated (1050 cGy; day -2), reconstituted with host-type T cells from PC- or FC-treated recipients (day -1; 0.1 × 106 T cells transferred), and challenged with fully allogeneic transplant (B6 donor bone marrow, 10 × 106 cells; day 0). In vivo HVGR was quantified on day 7 post-BMT by cytokine capture flow cytometry: absolute number of host CD4+ T cells secreting IFN-g in an allospecific manner was ([x 106/spleen]) 0.02 ± 0.008 in recipients of PC-treated T cells and 1.55 ± 0.39 in recipients of FC-treated cells (p<0.001). Similar results were obtained for allospecific host CD8+ T cells (p<0.001). Our second objective was to characterize the host immune barrier for engraftment after PC treatment. BALB/c mice were treated for 3 days with PC and transplanted with TCD B6 bone marrow. Surprisingly, such PC-treated recipients developed alloreactive T cells in vivo and ultimately rejected the graft. Because the PC-treated hosts were heavily immune depleted at the time of transplantation, we reasoned that failure to engraft might be due to host immune T cell reconstitution after PC therapy. In an experiment performed to characterize the duration of PC-induced immune depletion and suppression, we found that although immune depletion was prolonged, immune suppression was relatively transient. To develop a more immune suppressive regimen, we extended the C therapy to 14 days (50 mg/Kg) and provided a longer interval of pentostatin therapy (administered on days 1, 4, 8, and 12). This 14-day PC regimen yielded CD4+ and CD8+ T cell depletion similar to recipients of a lethal dose of TBI, more durable immune depletion, but again failed to achieve durable immune suppression, therefore resulting in HVGR and ultimate graft rejection. Finally, through intensification of C therapy (to 100 mg/Kg for 14 days), we were identified a PC regimen that was both highly immune depleting and achieved prolonged immune suppression, as defined by host inability to recover T cell IFN-g secretion for a full 14-day period after completion of PC therapy. Finally, our third objective was to determine with this optimized PC regimen might permit the engraftment of MHC disparate, TCD murine allografts. Indeed, using a BALB/c-into-B6 model, we found that mixed chimerism was achieved by day 30 and remained relatively stable through day 90 post-transplant (percent donor chimerism at days 30, 60, and 90 post-transplant were 28 ± 8, 23 ± 9, and 21 ± 7 percent, respectively). At day 90, mixed chimerism in myeloid, T, and B cell subsets was observed in the blood, spleen, and bone marrow compartments. Pentostatin therefore synergizes with cyclophosphamide to deplete, suppress, and limit immune reconstitution of host T cells, thereby allowing engraftment of T cell-depleted allografts across MHC barriers. Disclosures: No relevant conflicts of interest to declare.

A Retrospective Study of Alemtuzumab Level, T Cell Chimerism and Graft Versus Host Disease Using Intermediate Dose Alemtuzumab for Matched Related and Matched Unrelated Reduced Intensity Transplantation.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3333-3333
Author(s):  
Andrew Charlton ◽  
Laura Spence ◽  
Venetia Bigley ◽  
Natasha Groves ◽  
Geoff Hale ◽  
...  
Keyword(s):  
T Cell ◽  
Linear Regression ◽  
Surface Area ◽  
Chronic Gvhd ◽  
Unrelated Donor ◽  
Full Dose ◽  
Cell Engraftment ◽  
Gvhd Prophylaxis ◽  
Reduced Intensity

Abstract Abstract 3333 Poster Board III-221 Alemtuzumab (CAMPATH 1H) is a well established agent for effecting in vivo T cell depletion and prevention of GVHD in reduced intensity transplants. Many studies indicate that full dose alemtuzumab (100mg in 5 daily doses of 20mg) induces profound immunodeficiency, almost completely ablating GVHD in Fludarabine and Melphalan (FM) matched related donor (MRD) and matched unrelated donor (MUD) transplants. In contrast, FM conditioning alone exposes patients to a high burden of acute and chronic GVHD. Accordingly, many transplant centres have adopted policies of intermediate alemtuzumab dosing of 50mg or less. While the pharmacokinetics, rate of T cell engraftment and incidence of GVHD are well described using full dose alemtuzumab, much less is known about the in vivo action of alemtuzumab at intermediate doses. Methods We report our experience of alemtuzumab at 30mg (day -2) for MRD and 60mg (30mg day -4 and day -2) for MUD transplants, which was adopted as standard GVHD prophylaxis for FM transplantation at our centre in 2006. We avoided giving alemtuzumab on day -1, since there is a steep drop in alemtuzumab level in the first 24 hours after infusion and the timing of stem cell infusion may vary considerably, especially with unrelated donor grafts. From May 2006 to May 2009, 24 patients received MRD and 27 patients received MUD transplants. Post transplant serum samples were available from 19 MRD transplants and 15 MUD transplants at day +1. In addition, day +3 samples were identified from 10 patients previously transplanted with 100mg alemtuzumab, 10 MUD receiving 60mg and 10 MRD transplants receiving 30mg. All patients gave consent for clinical follow up and post transplant serum sampling for research purposes, according to protocols approved by the local research ethics committee of Northumberland and North Tyneside. Alemtuzumab concentration was measured by a validated flow cytometry assay, as previously described. Results The mean (SEM) alemtuzumab concentration (micrograms/ml) on day +1 was 2.9 (0.3) after 30mg and 4.6 (0.6) after 60mg (t test p<0.01). On day +3 the levels were 2.4 (0.2); 4.0 (0.6); 8.4 (1.9) after 30mg, 60mg and historical controls of 100mg, respectively (p<0.05 between each dosing level). There were significant inverse correlations between patient surface area and alemtuzumab concentration by linear regression for both 30mg (r2 0.51 p<0.01) and 60mg dosing (r2 0.18 p<0.05). A trend for lower alemtuzumab with increasing cell dose was also observed, although this may be related indirectly to patient weight. All patients achieved >95% myeloid engraftment by day 100. Median (range) T cell engraftment was variable and significantly higher after MUD transplants: 70% (9-99%) than MRD transplants: 21% (5-85%; Mann Witney p <0.05). T cell chimerism was inversely correlated with alemtuzumab level in MRD transplants by linear regression (r2 0.37; p <0.05) but this trend was not apparent in MUD transplants. The incidence of acute GVHD was also greater after MUD transplantation at 47% (grade I or II) compared with 11% (grade I only) for MRD recipients. There was no significant relationship between GVHD grade and alemtuzumab level in either group. There were 2/24 non-relapse deaths after MRD and 3/27 following MUD transplantation; none were due to GVHD. The incidence of chronic GVHD is currently being evaluated. Conclusion This analysis demonstrates predictable dose and surface-area relationships with alemtuzumab level in patients receiving FM conditioning. It also reveals that significantly less than 100mg alemtuzumab confers reliable GVHD prophylaxis in both MRD and MUD recipients, although at least twice the level of alemtuzumab is required to achieve comparable GVHD control in MUD transplants. Finally, it is notable that T cell chimerism at day 100 is directly related to alemtuzumab level at day +1 in MRD transplants. We conclude that optimisation of immune reconstitution and GVHD control using alemtuzumab in vivo depends upon due consideration of both recipient and donor factors, notably the size of the recipient and the origin of the graft. Disclosures Groves: BioAnaLab: Employment. Hale:BioAnaLab: Employment, Equity Ownership.

The Equilibration of Peripheral Blood and Tissue CD3+ T Cell Engraftment Is Influenced by Graft Versus Host Disease Following Reduced Intensity Conditioning Stem Cell Transplantation

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2546-2546
Author(s):  
Victoria Harries ◽  
Rachel Dickinson ◽  
Venetia Bigley ◽  
Matthew Collin
Keyword(s):  
T Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Peripheral Blood ◽  
Graft Versus Host ◽  
Post Transplant ◽  
Cell Engraftment ◽  
Donor T Cells ◽  
Patients At Risk ◽  
Reduced Intensity

Abstract Abstract 2546 Alemtuzumab-containing reduced intensity transplantation regimens frequently induce a state of partial T cell chimerism in the blood of the recipient. It has been widely shown that partial T cell chimerism is associated with freedom from graft versus host disease (GVHD) and that the occurrence of GVHD is often associated with rapidly rising donor T cell engraftment. The mechanism by which this occurs remains unknown and recipient cells may be killed, out-competed for homeostatic niches or simply diluted out by expanding donor T cells. The skin, a target organ of GVHD, normally contains T cells which enter from the blood in the steady state. Studies in mice have highlighted the gate-keeping function of inflammation in allowing trafficking of host-reactive donor T cells into tissues during conversion from mixed to full donor chimerism in blood. This implies that the equilibration of donor engraftment in the blood and tissue may occur more rapidly in patients at risk for GVHD. To test this hypothesis, we set out to define the relationship between skin and blood donor T cell engraftment in patients with and without GVHD. Methods: We studied a group of 51 patients receiving fludarabine melphalan (FM) conditioning with alemtuzumab 30mg for matched related donors and 60mg for matched unrelated donors. Skin biopsies were obtained at 28 and 100 days post transplant, dermal T cells isolated by migration and chimerism assessed in sex-mismatched transplants by combined immunofluorescence/in situ hybidization for XY chromosomes. Peripheral blood myeloid (CD15+) and T cell (CD3+) chimerism was determined by short tandem repeat amplification at monthly intervals after transplantation. All patients gave consent for clinical follow up and post transplant blood and skin sampling for research purposes, according to protocols approved by the local research ethics committee of Northumberland and North Tyneside. Results: All patients achieved >95% myeloid engraftment by day 100. Median (range) T cell engraftment was variable and significantly higher after MUD transplants: 70% (9-99%) than MRD transplants: 21% (5-85%; Mann Witney p <0.05). The incidence of acute GVHD was also greater after MUD transplantation at 47% (grade I or II) compared with 11% (grade I only) for MRD recipients. Overall a positive correlation was observed between donor T cell engraftment in skin and blood at all time points (r = 0.5792; P 0.0187) and at 100 days (r = 0.6570; P 0.0281). Analysis of the data with respect to GVHD showed a further interesting finding. Patients who developed GVHD had the closest correlation between blood and skin donor engraftment, even when they were in a state of partial T cell chimerism prior to the onset of GVHD. Patients who did not develop GVHD but nonetheless eventually achieved full donor engraftment in the blood tended to show lower levels of donor T cell engraftment in the dermis at day 100. Individual examples of patients who did not develop GVHD are: blood 77%, dermis 37%; blood 77%, dermis 6%; blood 92%, dermis 25%, compared with patients who did develop GVHD: blood 55%, dermis 56%; blood 90%, dermis 75%; blood 100%, dermis 100%. Conclusion: This analysis supports the hypothesis that the equilibration of blood and tissue donor T cells is influenced by GVHD and may offer a means to predict patients at risk of GVHD after withdrawal of immunosuppression or donor lymphocyte infusion. Disclosures: No relevant conflicts of interest to declare.

Absence of Graft Failure and Excellent Long Term Survival Following Fludarabine-Based Reduced Intensity Hematopoietic Stem Cell Transplantation In Heavily Transfused Patients with ATG-Refractory Severe Aplastic Anemia and Other Bone Marrow Failure Syndromes

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 517-517
Author(s):  
Jeremy Pantin ◽  
Xin Tian ◽  
Nancy Geller ◽  
Catalina Ramos ◽  
Lisa Cook ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Aplastic Anemia ◽  
Graft Rejection ◽  
Graft Failure ◽  
Acute Gvhd ◽  
Bone Marrow Failure ◽  
Chronic Gvhd ◽  
Abo Incompatibility ◽  
Bone Marrow Failure Syndromes

Abstract Abstract 517 Heavily transfused and alloimmunized patients with bone marrow failure syndromes including aplastic anemia have an increased risk of graft rejection following conventional allogeneic bone marrow transplantation. Results from pilot trials suggest the addition of fludarabine to the conditioning regimen reduces the risk of graft rejection in patients at high risk for this complication. Here we report the results of a fludarabine-based transplant approach in 56 patients with severe aplastic anemia (SAA) or other bone marrow failure syndromes (SAA n=31, MDS-RA n=6, PNH n=16, PRCA n=2, DBA n=1) who were transplanted from May 1999 to November 2008 at the NHLBI. Forty one percent of patients were found to be alloimmunized (median 82% PRA) prior to transplantation as a consequence of prior transfusions. Seventy three percent of patients had received antibody-based immunesuppressive therapy at a median of 303 days (range 21 to 2588) prior to transplantation (horse-ATG n=34, rabbit-ATG n=5, alemtuzumab n=1 and daclizumab n=1). Conditioning with fludarabine (25 mg/m2 × 5 days), ATG (40mg/kg × 4 days) and cyclophosphamide (60mg/kg × 2 days) was followed by infusion of an un-manipulated G-CSF mobilized allograft from an HLA matched (n=52) or single antigen mismatched (n=4) relative. GVHD prophylaxis consisted of cyclosporine (CSA) either alone (n=2) or combined with mycophenolate mofetil (n=10) or mini-dose methotrexate (n=44). The median CD34+ cell dose was 6.6 × 106 cells/kg (range 1.7 to 21.1 × 106 cells/kg) and the median CD3+ cell dose was 2.6 × 108 cells/kg (range 0.5 to 6.9 x108 cells/kg). Nearly half (46 %) of patients received an ABO incompatible allograft (major mismatch n=15; minor mismatch n=11). Despite a high prevalence of pre-transplant alloimmunization, graft rejection and/or graft failure did not occur, with all patients achieving sustained donor engraftment in both myeloid and T-cell lineages. The median time to achievement of full donor (>= 95%) myeloid and T-cell chimerism was 15 and 30 days respectively. Neutrophil and platelet recovery occurred at a median 15 (range 6 to 24) and 12 (range 5 to 168) days respectively. Major ABO incompatibility was associated with delayed donor erythropoiesis; reticulocyte recovery (> 60 K/μ L on two occasions) occurred at a median 17 days in those without major ABO incompatibility and 42 days in the recipients of a major ABO mismatched graft, where clearance anti-donor isohemagglutinins was delayed a median 171 days following transplantation. CMV reactivation occurred in 31/50 (62%) patients at risk although no patients died from CMV related mortality. With a median follow-up of 4.5 years (range 1.8–11 years) in surviving patients, overall survival was 87.1%. There were 5 treatment related deaths with two attributable to steroid refractory acute GVHD and one attributable to extensive chronic GVHD. The cumulative incidence of Grade II-IV, III-IV and steroid refractory acute GVHD was 51.8%, 30.4% and 21.4% respectively. The cumulative incidence of chronic GVHD was 72% (23.2% limited and 48.9% extensive), with 42.5% who developed cGVHD having resolution of symptoms allowing discontinuation of systemic immunosuppressive therapy. Conclusion: Fludarabine-based allogeneic peripheral blood stem cell transplantation achieves excellent donor engraftment and long-term disease free survival in heavily transfused and alloimmunized patients with ATG refractory SAA and other nonmalignant hematological disorders associated with bone marrow failure. Efforts to reduce the high incidence of GVHD associated with this approach without increasing the risk of graft failure by manipulating the cellular content of the allograft are currently being explored. Disclosures: No relevant conflicts of interest to declare.

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