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Hematopoietic stem cell transplantation is a potent curative treatment option for patients suffering from high-risk AML and MDS. However, not in all of our patients a suitable HLA-matched donor could be identified in time. To evaluate the feasibility and outcome of T-cell-replete (TCR) HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) utilizing post-transplantation high-dose cyclophosphamide (PTCY) in the context of sequential therapy in patients with high-risk, relapsed/refractory and progressive AML and MDS, we retrospectively analyzed the course of 64 patients (AML n=61, MDS n=3; median age: 50 years; male n=30) transplanted between 2009 and 2015 at our center. Disease was advanced in 55 patients including 24 patients with relapse after a first allogeneic transplantation. 54 patients presented with active disease at time of haplo-HSCT. Donors (median age: 38 years; male n=30) were fully HLA-haplotype mismatched (5/10 HLA-loci) in 48 cases (77%). All patients received sequential therapy prior to haplo-HSCT combining cytoreductive chemotherapy (clofarabine n=34; FLAMSA n=25; FLAG-Ida n=2; others n=3) and reduced-intensity conditioning (RIC) which was started after three days of rest thereafter. Conditioning was drug-based in 42 patients receiving fludarabine, cyclophosphamide (CY) and melphalan (110 mg/m2) while it was TBI-based in the others (n=22) consisting of fludarabine and CY plus either 4 (n=20) or 2 Gy TBI (n=2). Post-grafting immunosuppression was high-dose CY given on day + 3 and +4, tacrolimus and mycophenolate mofetil (both started on day +5) in all patients. Unstimulated bone marrow was the graft source in 37 patients. One graft rejection was observed after conditioning with 2 Gy TBI. Neutrophil/platelet engraftment was achieved in 49/58 evaluable patients at a median of 16 (range: 14-27) and 20 (range: 13-74) days, respectively. Acute GvHD grade II-IV occurred in 19 patients (30 %) while it was severe (grade III-IV) in only 3 (5 %). Chronic GvHD was most frequently mild (n=9) to moderate (n=8); one severe chronic GvHD occurred. Severe (grade III-IV) mucositis, hemorrhagic cystitis and hand-foot syndrome/rash were observed in 10, 5 and 2 patients, respectively; no patient developed VOD. Kidney failure requiring hemodialysis occurred in 7 patients. CMV reactivation was observed in 28 of 47 patients at risk (59 %) and EBV in 3, while only one patient developed CMV disease (pneumonia) and no patient developed PTLD. Probable or proven (n=2) invasive aspergillosis was diagnosed in 10 patients. One-year non-relapse mortality was 27.5 % (95% CI 17-41). After a median follow up of 21 months (range: 3-64), estimated one-year overall survival (OS) was 55 % (95 % CI 41-66), and one-year disease-free survival (DFS) was 43 % (95 % CI 26-51). At two-years after sequential haplo-HSCT OS and DFS were both 39 % (95 % CI 26-51). In summary, sequential therapy in the setting of RIC-TCR haplo-HSCT using PTCY is well tolerated with low rates of GvHD and acceptable NRM in patients with high-risk AML and MDS, while providing an effective anti-leukemic activity in advanced disease. Results are comparable to data of a historical cohort of patients with high-risk AML and MDS undergoing sequential therapy using the FLAMSA-RIC protocol in a HLA-matched setting, as reported by our group previously. Thus, we suggest that donor availability can be expanded in patients with high-risk and advanced AML/MDS who lack a conventional donor or need promptly access to a donor due to aggressive disease. Disclosures Hausmann: Sanofi-Aventis: Other: advisory board. Tischer:Sanofi-Aventis: Other: advisory board. Off Label Use: clofarabine in adults; efficacy is shown in myeloid blasts;.

Background: Allogeneic stem cell transplantation (SCT) can provide long-term disease control in selected patients with relapsed refractory NHL. Restricted availability of a matched sibling donor limits its use especially for patients with rapidly progressing disease in whom unrelated donor search cannot be awaited and in patients from ethnic minorities. Donor sources such as haplo-identical relatives or cord blood represent reasonable alternatives but data of alternative donor transplants in lymphoma is sparse. We therefore intended to compare outcome after transplants performed with sibling or fully matched unrelated donors with alternative sources such as cord blood and haplo-identical donors. Methods: Information of patients with mantle cell lymphoma (MCL), DLBCL, T-cell lymphoma (TCL) and follicular lymphoma (FL) who received an SCT from a sibling donor (SIB), 10/10 matched unrelated donor (MUD), haplo-identical donor (HAPLO) or cord blood (CORD) between 2007 and 2012 was downloaded from the EBMT database. Comparisons of outcome after transplants from different donors were performed with regard to overall survival (OS), non relapse mortality (NRM), relapse (REL) and acute GVHD incidence. For comparisons between donors SIB has been chosen as the reference group. Results: 2798 patients with NHL were identified in the EBMT database meeting the inclusion criteria. 2065 received a transplant from a SIB, 447 from a MUD, 167 from CORD (18 MCL, 36 DLBCL, 43 FL, 70 TCL) and 119 from a HAPLO donor (16 MCL, 30 DLBCL, 22 FL, 51 TCL). 66% were male and 34% female patients. Median age at transplant was 49 years (range: 18-72). 24% (n=684) had DLBCL, 27% (n=755) FL, 17% (n=464) MCL and 32% (n=895) TCL. 56% received their transplant in CR, 17% in PR and 27% had active disease at SCT. Active disease was more common in the HAPLO group (p Median follow-up after SCT was 27 month (CI 25 to 29). OS of patients who received an alloSCT from a SIB or MUD was not significantly different, whereas OS of HAPLO and CORD transplants was significantly worse than SIB transplants (HR 1.9 CI 1.5 -2.5, HR 1.8 CI 1.4 -2.2, p < 0.0001, Figure 1). Worse OS after alternative donor transplant (reference SIB) was observed across all studied disease entities. Relapse incidence after conventional transplants (SIB, MUD) and alternative donor transplants (HAPLO, CORD) was not significantly different within the whole group (HAPLO: HR 1.2 95% CI 0.9-1.8 p= 0.23; CORD: HR 1.1 95% CI 0.7-1.4, p=0.74; Figure 1) and across all studied disease entities. In contrast, whereas NRM incidence was not significantly different between SIB and MUD, it was, but significantly higher with alternative donor transplants (HAPLO: HR 1.8 95% CI 1.3-1.8, p80%) and conditioning intensity (RIC vs. MAC) confirmed worse OS for HAPLO (HR 1.5 CI 1.2-2.0, p=0.003) and CORD (HR 1.6 CI 1.3-2.0, p Conclusions: Alternative donor transplants are a valuable option if no suitable SIB or MUD donor is available. With the limited number of patients studied here, relapse incidence after alternative donor transplants was not significantly different from conventional transplants. Higher NRM incidence in alternative donor transplants might be improved with increasing refinement of the procedure, such as post-transplant cyclophosphamide approaches. Figure 1) Outcome (OS, Rel, NRM) after alloSCT with different donors Figure 1). Outcome (OS, Rel, NRM) after alloSCT with different donors Disclosures No relevant conflicts of interest to declare.

By reducing treatment intensity allogeneic hematopoietic stem cell transplantation (allo-HSCT) has become feasible for elderly patients. Different reduced-intensity conditioning (RIC) regimens are available, but there is little consensus about the optimal preparative regimen to use, in particular with regard to the outcomes counterbalancing the aim of feasibility and tolerability with higher rates of relapse. Here, we retrospectively evaluate the outcome of sequential therapy employing RIC with fludarabine 30 mg/m2, cytarabine 2g/m2 and amsacrine 100 mg/m2 for 4 days (FLAMSA; Schmid C et al. JCO 2005) followed by busulfan 10 x 0.8 mg/kg (FLAMSA-Bu) compared to RIC utilizing fludarabine 5 x 30 mg/m2, carmustine (BCNU) 2 x 150 mg/m2 and melphalan 110 mg/m2 (FBM; Marks R et al. Blood 2008) in elderly patients treated consecutively at our institution between July 2005 and October 2012. We analyzed the course of 114 patients (pts) with acute myeloid leukemia (AML; n=99) or myelodysplasia (MDS; n=15) aged ≥ 59 years with 59 pts aged ≥ 66 years who were treated with either FLAMSA-Bu (n=66; n=24 ≥ 66 years) or FBM (n=48; n=35 ≥ 66 years). All patients received sero-therapy with anti-thymocyteglobuline (ATG). Median patient age was 66 years for the entire cohort (68 years FBM; 64 years FLAMSA-Bu). 36 patients (75%) of the FBM and 42 patients (63 %) of the FLAMSA-Bu group suffered from high risk disease defined as relapsed or refractory AML or refractory anemia with excess of blasts in transformation (RAEB-T). The hematopoietic cell transplantation comorbidity index (HCT-CI) was higher for the patients of the FBM group than for the FLAMSA-Bu group with 26 (54 %) versus (vs) 24 patients (36 %) scoring ≥ 2 (p 0.085). Graft source after conditioning with FBM/FLAMSA-Bu was bone marrow (1/2), G-CSF mobilized peripheral blood stem cells (40/62) and double-umbilical cord-blood (7/1). In 23 pts (20 %) HLA-matched related and in 91 pts (80 %) HLA-matched unrelated donor transplantation was performed. Engraftment failure was observed in 1 patient after FLAMSA-Bu, while engraftment was achieved in all evaluable patients of the FBM group in a median of 23 days vs 18 days after FLAMSA-Bu (p 0.003), while 7 pts with double-umbilical cord-blood transplantation where included in the FBM group vs 1 pt in the FLAMSA-Bu group. Non-hematological treatment-related acute toxicity ≥ CTC III (gastrointestinal, hepatic, cardiovascular, renal, centralnervous system) occurred in 12/48 pts (25 %) after FBM and in 18/66 pts (27 %) after FLAMSA-Bu. Incidence of severe acute (III-IV) and chronic GvHD was 22.9 %/16.6 % for FBM vs 18.2 %/19.7 % for FLAMSA-Bu, respectively. After conditioning with FBM 2/48 pts vs 9/66 pts after FLAMSA-Bu were diagnosed with a secondary malignancy (p 0.08). Non-relapse mortality (NRM) after 12 months was 26.8 % for FBM versus 25.2 % for the FLAMSA-Bu group. Incidence of relapse after FBM vs FLAMSA-Bu conditioning was 22.9 % vs 15.2 % after 1 year and 31.3 % vs 16.7 % after 2 years. Occurrence of relapse was significantly related to an incomplete or mixed chimerism (donor cells ≤ 95 % in peripheral blood and/or bone marrow) at day +30 (p 0.001). After a median follow up of 31.4 months (range 4.4-97.5) estimated overall survival (OS) and relapse-free survival (RFS) after 2 years was 55.4 % and 51.4 % for the FBM vs 58 % and 56.7 % for the FLAMSA-Bu group, respectively. Analyzing different subgroups, FBM conditioning might be favorable for pts aged ≥ 66 years when suffering from high risk AML (n=26): Within this group 1-year OS after FBM vs FLAMSA-Bu was 71.4 % vs 66.7 % (p 0.58) and 1-year RFS was 71.4 % vs 58.3 % (p 0.59), respectively. Notably, for pts at highest risk (aged ≥ 66 years and suffering from secondary or therapy-related AML; n=24) the benefit of FBM conditioning becomes more pronounced: 1-year OS after FBM vs FLAMSA-Bu was 62.5 % vs 37.5 % (p 0.26) and 1-year RFS 54.2 % vs 37.5 % (p 0.17). Both conditioning regimens are feasible, and provide similar rates of acute toxicity, NRM and GvHD. There might be evidence for a benefit of conditioning with FBM for the subgroup of “the oldest patients at highest risk”. Taking into account that there is an increasing group of ‘medically fit’ elderly patients in the field of allogeneic transplantation, prospective clinical trials are needed to investigate different conditioning regimens considering their special requirements. Disclosures No relevant conflicts of interest to declare.

Background: Relapse of acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is frequently treated with 2nd allo-HSCT. Donor change has not yielded a significantly different outcome over choosing the original HLA-identical donor (Christopeit et al., JCO 2013). Using a haploidentical donor at second allo-HSCT might represent a feasible option (Tischer et al., BMT 2014) Study design and population: To define the role for second haploidentical allo-HSCT for AL relapsing after 1st allo-HSCT, a retrospective analysis was conducted 63 consecutive patients (female n=30, male n=33; AML n=51, ALL n=12) from 9 German centers were included. Median age was 40 years (range, 16-65). Grafts at 1st allo-HSCT were from matched related (32%), matched unrelated (33%), mismatch unrelated (18%), haploidentical donors (6%), and other donors, including cord blood (8%). Median duration of complete remission (CR) after 1st allo-HSCT was 414 days (range, 18-1633). Relapse was initially treated by cytoreductive chemotherapy in all cases; stage at start of conditioning for haploidentical second allo-HSCT was CR in 27%, active disease in 66% and not evaluated in 8%. Conditioning for second HSCT was myeloablative/reduced in 14%/86% To overcome the HLA barrier, 23 patients (36%) received ex vivo T-cell depletion (TCD), following either CD3/CD19 negative or CD34 positive selection. 4 patients received in vivo TCD only, two received no TCD at all, and 35 patients (55%) received high-dose cyclophosphamide post-transplant according to the Baltimore protocol. Results: Neutrophil engraftment was achieved after a median of 12 days (range, 8-26). 50 patients (78%) achieved CR after 2nd haploidentical allo-HSCT, out of which 23 (46%) relapsed again. After a median follow-up of 425 days, 47 patents had died, 22 from leukemia, and 25 from treatment-related causes. Kaplan-Meier estimated overall survival at one and two years from haploidentical second HSCT was 41+/-6% and 19+/-6%. Conclusions: Haploidentical second allo-HSCT is a promising approach to the treatment of AL relapse after first allogeneic transplant. OS rates at least comparable to alternative treatments were observed. Different strategies to overcome the HLA barrier seem feasible. This retrospective study was registered as NCT01997918 at clinicaltrials.gov. Maximilian Christopeit and Johanna Tischer as well as Wolfgang Bethge and Christoph Schmid contributed equally to this work. Disclosures No relevant conflicts of interest to declare.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a valuable treatment option for patients with relapsed or refractory lymphoma including patients with relapse after a first autologous HSCT. However, outcome in non-remission patients is still poor. Here we report the feasibility and efficacy of a protocol using the concept of sequential therapy with clofarabine induction chemotherapy followed by a HLA-haploidentical HSCT in the treatment of patients with advanced non-remission lymphoma. 16 adults (11 male, median age: 53 years, median comorbidity index: 3) with MCL (n=7), CLL (n=1), AITL (n=2), secondary DLBCL (n=2), DLBCL (n=2), follicular lymphoma (n=1), B- lymphoblastic lymphoma (n=1) were treated between September 2010 and February 2013. After induction-chemotherapy with clofarabine (5x30 mg/m² IV), followed by 3 days of rest, a reduced intensity conditioning (RIC) consisting of fludarabine/cyclophosphamide plus melphalan 110 mg/m2 IV was performed prior to a T-cell replete HLA-haploidentical HSCT. High dose cyclophosphamide (Cy) was administered for post-grafting immuno-suppression followed by mycophenolate mofetil and tacrolimus. The median number of immuno-chemotherapy attempts prior to haploidentical HSCT was 4 including 8 autologous HSCT. None of the patients were in complete remission (CR) prior to haploidentical HSCT. After salvage therapy and prior to haploidentical HSCT, progressive disease (PD) was documented in 9 patients with one patient being primarily refractory, while in 7 patients a partial remission (PR) was observed. Neutrophil engraftment was achieved in 16 patients (100%) within a median of 21 days (range 14-36) and platelet engraftment in 14 patients (88%) within a median of 30 days (range 18-115). No primary graft rejection occured. By day +30 CR was achieved in 4 patients (25%) and PR in 11 patients (69%), whereas 1 patient (6%) showed PD. Full donor chimerism on day +30 was detected in all 16 patients. By day +100, 8 of the 14 evaluated 14 patients (57%) achieved CR, 4 (29%) PR, and only 2 (14%) had relapsed. Full donor chimerism was detected in 13 (93%) patients. The rate of acute GvHD grade II-IV was 31%, while chronic GvHD occurred in 3 of 14 (21%) evaluable patients (21%). Non hematologic regimen-related grade III-IV toxicity was observed in 9 patients (56%), and included most commonly transient elevation of liver enzymes (38%), mucositis (19%), and nausea and vomiting (19%). Creatinine elevation (6%), hand-foot syndrome (6%) and haemorrhagic cystitis (6%) were rare. After a median follow up of 14.5 months (range 5.7-35) 4 patients had relapsed, and 4 patients had died, while death was lymphoma-associated only in one patient. Causes of non-relapse mortality (NRM) were haemorrhagic cerebral bleeding in one patient (day +101), and toxicity/infection in 2 patients (day +141; day +156). Cumulative incidence of NRM was 0% on day +100 and increased up to 20% (7-50) on day +360. Estimated one-year overall survival and progression-free survival were 75% (95 CI 46-90) and 56% (95 CI 30-76), respectively. Sequential therapy combining cloforabine induction-chemotherapy and HLA-haploidentical HSCT using RIC, a T-cell replete graft and high dose Cy post-transplant is feasible, shows a favourable toxicity profile and furthermore achieves significant anti-lymphoid activity in patients with advanced non-remission lymphoma. These early results are promising, but longer follow up is needed. Disclosures: Off Label Use: Clofarabine off label use in adults. Hausmann:Sanofi: Travel support Other. Tischer:Sanofi: Travel support Other.

Abstract 3071 Background: Prognosis of relapse after first allogeneic hematopoietic stem cell transplantation (allo-HSCT) is poor, and no standard treatment is available. Second HSCT (HSCT2) is a valuable treatment option for selected patients. Change of donor for HSCT2 is a frequently used strategy to enhance the graft-versus leukemia-activity, although its role for improving the outcome is still unclear. However, identification and activation of a new donor for HSCT2 is time consuming and might delay or even prevent a second transplant. In contrast, haploidentical family donors are rapidly available in the vast majority of patients and might therefore be an alternative for HSCT2, once change to a new donor is planned. Based upon these considerations, HSCT2 from haploidentical family donors was used as preferred treatment for acute leukemia relapse after allo-HSCT in our transplant center since August 2009. According to the concept of sequential therapy (as introduced by the FLAMSA-RIC regimen), patients initially received cytoreductive chemotherapy, followed, after three days of rest, by reduced intensity conditioning (RIC). Based on the Baltimore protocol for haploidentical HSCT using RIC and post-transplant cyclophosphamide for depletion of allo-reactive T-cells, individual and disease-specific modification of this regimen were used for preparation before HSCT2. Patients and Methods: Fourteen adult patients (7 male, median age: 37 years) suffering from AML (n=11) or ALL (n=3) with an ECOG score of Results: Neutrophil and platelet engraftment was achieved in 12 (85,7%) and 10 (71,4%) patients, respectively. Median time to neutrophil engraftment was 32 days (range 24–90). No primary graft rejection was observed. Complete remission could be induced by day +30 in 11 patients (78,6%), whereas 1 patient died early and 2 patients had refractory disease. Full donor chimerism by day +30 was achieved in 10 patients (71,4%). After a median follow-up of 6 months (range 4 days–33 months) cumulative incidence of non-relapse mortality at day + 30, + 100 and +360 was 7%, 24% and 24 %, respectively. Rate of grade II-IV acute GvHD was 24,7%. Mild or moderate chronic GvHD was seen in 2 patients (14,3%). 8 patients died from relapse (n=4), infection (n=3) or infection and toxicity (n=1). Estimated overall survival and progression-free survival at one year from HSCT2 was 53 % (+/− 14 %) and 36 % (+/− 17 %), respectively. Infection was frequent detected in 13 (92,9%) patients with at least one episode of neutropenic fever in 8 patients, probably or proven invasive aspergillosis in 5 patients and a moderate rate of virus-reactivation/-infection (CMV 21,4%, HSV 14,2%, EBV 28,6%, HHV-6 28,6%, Polyomavirus 28,6%, Adenovirus 21,4%,). No patient developed a post-transplant lympho-proliferative disorder. Regimen related grade III-IV toxicity was observed in 9 (64,3%) patients with transient elevation of liver enzymes in 7 (50%), mucositis in 5 (35,7%), headache in 5 (35,7%), hand-foot syndrome in 3 (21,4%), hyper-bilirubinemia in 3 (21,4%) and severe deterioration of kidney function in 2 (14,3%) patients, respectively, as the most common observed toxicities. Conclusion: Haploidentical HSCT2 following initial cytoreduction with clofarabine, RIC and high-dose cyclophosphamide post-transplant is feasible in patients with acute leukemia relapsing after first allo-HSCT. Early results are promising, but long-term results are still pending. Disclosures: Off Label Use: Clofarabine is a novel purine nucleoside with immunosuppressive and anti-leukemic activity in hematologic malignancies, off-label use in adults.

Abstract 4540 Microangiopathy (MA) and graft-versus-host disease (GvHD) are serious complication after allogeneic hematopoietic cell transplantation (HCT). MA is comparable to a slight form of thrombotic thrombocytopenic purpura (TTP), characterized as de novo thrombocytopenia, hemolysis, evidence of fragmentocytes in the blood, hypertension, cerebral confusion and uremic syndrome. Conglomerates of platelets and uncleaved multimere of vWillebrand-Factor (vWf)) are the pathophysiological correlate and result in multiple occlusions of microvessels. Up to now the exact pathomechanism for chronic GvHD (cGvHD) is unknown but oftenly associated with decreasing platelets counts. In patients (pts) with cGvHD we previously described an increased number of vWf +and CD34+ microvessels and of CD8+ T-cells in the bone marrow (Hill,W Blood 112 abstract No 1166, 2008). The aim of this study is to screen bone marrow biopsies of pts after HCT for histological changes of vascular quality regarding to MA and correlate these findings with the development of cGvHD. Bone marrow biopsies of 36 pts (25 male, 11 female, 45 years median, range 18–64) after HCT (day 105 to 4623) were screened for overall number of vWf+ vessels, the number of sinus with a thick wall of vWf + deposit with a size > 15 × 8μ (plaquesinus) and the number of vWf+ deposit without evidence of sinus (plaques) as well as the number of megakaryocytes between Oct 2001 and Jul 2006. Morphological findings were correlated with GvHD or non-GvHD and with MA by the well known grading (aMA) at the time of acute GvHD (aGvHD) and with as a modificated grading (cMA) at the time of simultaneous cGvHD. Results: 26 of 36 pts had cGvHD (6 with limited and 20 with extensive disease). 22 had aGvHD before and 4 did not. 8 of the 36 pts had neither aGvHD nor cGvHD, 2 pts suffered from aGvHD. Regarding to aMA a moderate grade was found in 14 pts, a mild form was detected in 15 pts, and 7 pts did not have any signs of aMA. The levels of maximal elevation of lactatdehydrogenase (LDH) and maximal decrease of platelets (each p value < 0,02) were as followed: absent grade LDH mean 248 U/L and platelets decrease mean 36 %; mild grade LDH 299 U/L and platelets 52 % and moderate grade LDH 505 U/L and platelets 70%. Additional parameters (each p Conclusion: Low grade MA was more often observed than expected from the literature. MA can be demonstrated morphologically by vWf+ deposits in endothelial-cells in bone marrow and can be graded also at the time of cGvHD. The high frequency of moderate grade at the time after engraftment with or without aGvHD is remarkable for development of a cGvHD with prognostic, pathogenetic and therapeutic relevance. From clinical, laboratory and morphological point of view microangiopathy seems to be part of aGvH reaction, followed by deposits of vWf+ material in the bone marrow, consumption of platelets by fixation to uncleaved multimere of vWf with the consequence of thrombocytopenia. Disclosures: Hill: Novartis: Research Funding.

Hematopoiesis of the host is a primary target organ of the graft-versus-host reaction. However histological analyses of the bone marrow are rarely reported. Here we report histological changes in the bone marrow of patients (pts) with and without chronic graft-versus-host disease (cGvHD). Bone marrow biopsies were obtained between 101 days and 4623 days (median:419 days) after transplantation as part of a controlled prospective phase ll study of patients with osteopenia/osteoporosis after allogeneic hematopoietic stem cell transplantation (HCT). Previously we reported an increased density of microvessels using an antibody against v. Willebrand factor (vW) (Hill W. et al Blood110, abstract No 1963; 2007). Here we report additional immunohistological and immunocytological findings in marrow and blood. We analyzed the number of CD34+ and vW+ microvessels as well as CD8+ suppressor/cytotoxic T-cells/mm² (T-S) in sequential biopsies of pts with (n=9) or without (n=6) cGvHD after median 2 years apart. Biopsies of 3 pts without HCT and without lymphoma involvement served as controls. Simultaneously lymphocyte subpopulations were evaluated in peripheral blood samples of pts with (n=16) or without (n=8) cGvHD. The pts were divided in 5 groups: neither aGvHD nor cGvHD; no cGvHD but acute GvHD before entry; cGvHD limited; cGvHD extensive without immunosuppression; cGvHD extensive with immunosuppression. Results: In the first biopsies the content of CD34+, vW+ microvessels and T-S cells were significantly higher in pts with cGvHD (group 3–5) than in those without cGvHD (group 1–2) (21,3 vs 8,2 p=0,03; 22,0 vs 9,2 p=0,002 respectively 106,2 vs 32,1 p=0,04). In the second biopsies these parameters were also increased in cGvHD: CD34+ (18,3 vs 11,2 p=0,02), vW+ (17,3 vs 9,0 p=0,08) microvessels and T-S cells (63,2 vs 37,8 p=0,27). The increased density of CD34+ and vW+ microvessels correlated with the number of T-S cells (p=0,05). As compared to normal controls we observed a significantly higher content of vW+ microvessels in all groups of transplanted pts (16,9 vs 4,2 p=0,03). In pts with cGvHD (group 3–5) CD34+ and vW+ microvessels were further increased (p=0,02 respectively p=0,002). At the time of the first biopsy the absolute T-S cell content in peripheral blood was moderately increased in group 5 (1124/ul) and minimally increased in group 2 (993/ul) (normal 270 – 880), whereas the overall T cell (CD3) content was normal in all groups. The percentage of activated T-S (HLA-DR+) cells was increased in all groups of transplanted pts (61,8% vs normal =33%; p=0,05). After two years T-S cells content was reduced in pts under immunosuppressive therapy (group 5) (1415 vs 900/ul; p=0.000) but remained increased over the norm. In group 4 T-S cell content was increased over the norm (800 vs 920/ul; p=0,043). In conclusion, sequential immunohistology and immunocytology analyses on bone marrow biopsies and peripheral blood provide evidence for the existence of a chronic graft-versus-host reaction of the bone marrow in pts with cGvHD. This is characterized by an increased content of CD34+ and vW+ microvessels and an increased content of T-S cells at least initially. However this reaction does not lead to a generalized hematopoietic insufficiency.

Allogeneic stem cell transplantation produces a strong graft-versus-leukemia effect which may be enhanced by HLA-mismatches and immune recognition as a result of pregnancy. Therefore we compared the results of HLA-haploidentical transplantation (N=113) to those of HLA-identical sibling (N=195) transplantation performed in the same time. Cases were matched by disease category (acute myeloid leukemia-myelodysplastic syndromes, AML/MDS, acute lymphoid leukemia ALL and lymphoma-chronic lymphocytic leukemia NHL/CLL) and stage of the disease (early, intermediate and advanced). HLA-haploidentical transplants were performed with unmodified bone marrow followed by CD6-depleted mobilized blood stem cells on day 6.; patients with leukemia were in more advanced disease in leukemia, they were younger and more often male. In multivariate analysis survival was influenced by HLA-mismatch, stage of the disease and age of the patient, but conditioning treatment and CMV-seropositivity had no significant effect. Transplant related mortality was influenced by the age of the patient and HLA-match, to a lesser extent by the disease category and the stage, whereas CMV-seropositivity and conditioning had no influence. Remission duration was dependent on the stage of the disease, the donor recipient gender combination and the conditioning treatment in univariate analysis; in multivariate analysis only CMV-seropositivity had a poor prognostic impact. In comparable disease stages the relapse rate was not different in HLA-haploidentical from HLA-identical transplantation as was the rate of acute GVHD. In contrast the rate of chronic GVHD was lower in HLA-haploidentical transplantation. In ALL, relapse rate and remission duration was inferior with non-myeloablative conditioning as compared to myeloablative total body irradiation. In HLA-haploidentical transplantation the response rate of leukemia was better in patients homozygous for the cross reactive HLA-C group given a transplant from a heterozygous donor suggestive of NK activity. This GVL activity was not associated with GVH activity. Similarly maternal donors were superior to paternal donors and female donors in male recipients better than other gender combinations for the control of leukemia without increased GVHD. Non-inherited maternal antigen (NIMA) and inherited paternal antigen (IPA) in the graft-vs-host direction had a weak influence on the relapse rate, but no influence on GVHD. On an observational basis several sons and daughters transplanted with stem cells from the mother had a strong GVL effect without any signs of GVHD. However two have been lost due to untreatable pulmonary complications. Donors with cytotoxic antibodies have been excluded from donation, but cellular reactivity will have to be assessed in more detail. Recent progress in controlling EBV-associated disease by selection of donor T cells without expansion will improve HLA-haploidentical transplantation and show the way to selecting donor with the appropriate immune repertoire including reactivity to leukemia.

Chronic GvHD (cGvHD) is associated with endothelial injury mediated by cytotoxic T lymphocytes and loss of microvessels in skin biopsies as well as increase of von Willebrand factor in plasma (BC Biedermann, Lancet 2002). Moreover an increased quantity of CD45RO positive lymphocytes has been observed in bone marrow biopsies (bmb) in CML pts with acute GvHD (aGvHD) grade III and lV, who were transplanted from unrelated donors (J Thiele, Bone marrow transplantation 2001). We analysed factors of T-cell activation and microvessels in bmb of pts with cGvHD to evaluate the function of the bone marrow in cGvHD. Methods: In an associated protocol of a prospective phase II study in 35 pts for the therapy of bone loss following HSCT with a bisphosphonate one bmb was taken prior of entry into the study and embedded in paraffin after decalcification. The interval between HSCT and time of biopsy was median 477 +/−998 days. For conventional semiquantitative evaluation of marrow and spongiosa a Giemsa staining was used. For immunological quantitative evaluation the following monoclonal antibodies were used with the APAAP method: CD34 and von Willebrand factor (VWF) for endothels of microvessels and CD45RO and CD8 for T-lymphocytes subsets. The pts were divided in 5 groups: 1. neither aGvHD nor cGvHD; 2. no cGvHD but aGvHD before entry; 3. cGvHD limited; 4. cGvHD extensive inactive; 5. cGvHD extensive active, needing immunosuppression. Results: Conventionally analysed no pt had evidence of vasculitis. 1 pt of group 4 had one small immunoreactive aggregate of lymphocytes another pt of group 5 had a diffuse infiltration with lymphocytes. 32 pts had no or very small reduction of spongiosa and 3 had severe reduction of spongiosa < 15%. The significant immunological results were: | Number/mm2 | 1. no GVHD (n=6) | 2. aGvHD before (n=4) | 3. cGvHD limited (n=5) | 4. cGvHD ext. inactive (n=8) | 5. cGvHD ext. active (n=12) | p (group No) | |:------------- | ---------------- | --------------------- | ---------------------- | ---------------------------- | --------------------------- | ---------------------- | | CD34+ vessels | 12,6 | 10,4 | 8,5 | 20,7 | 27,9 | < 0,001 (1,2,3 vs 4,5) | | V. Willebrand | 6,5 | 13,2 | 18,6 | 17,6 | 18,9 | 0,005 (1,2 vs 3,4,5) | | CD8+ | 5,8 | 4,0 | 6,8 | 10,2 | 25,3 | 0,034 (1,2,3 vs 4,5) | The number of CD34 as well as the number of vWF positive microvessels increased with the grade of involvement and activity of cGvHD (11,1 vs 25,3 respectively 8,7 vs 18,1). Additionally the content of CD8 positive lymphocytes increased with the grade and activity of disease. In contrast to reported skin biopsies, bone marrow capillaries were not destroyed by cytotoxic lymphocytes with increased activity. The bone marrow seems to show a different immunological reaction in contrast to pts with cGvHD of whom the target organs are skin, liver or gut. This was not observed on conventional biopsies. Further studies will be directed to the pattern of microvessels with regard to hematopoietic function and relapse.

Decreased bone mineral density (BMD) has been found to be a relatively common complication following haematopoietic cell transplantation (HCT). Only some studies exist about therapy with antiresorptive substances such as bisphosphonates. These studies analyse either short time therapy or only the use for female patients (pts). The aim of this study was to test the effect and tolerance of zoledronic acid in long time survival pts after HCT. Methods: 40 pts with osteoporosis (WHO T-score Table 1: baseline ° 1 yr°* 2 yrs°* % 1 yr* % 2 yr* °g/cm² mean values (+/−SD) *p=0.000 vs baseline LS 0.97+/−0.15 1.04+/−0.18 1.10+/−0.18 7.4+/−4,8 11.6+/−6.0 FH 0.82+/−0.10 0.87+/−0.11 0.91+/−0.10 5.6+/−5.3 7.5+/−7.0