Circulating progenitor cells in patients with familial hypercholesterolemia.

OBJECTIVE: Familial hypercholesterolemia (FH) is a genetic disease with very high levels of circulating low density lipoprotein cholesterol (LDL-C) levels that leads to accelerated atherosclerosis. Lipoprotein apheresis is an effective treatment option for patients with FH and results in reduced cardiovascular morbidity and mortality. Circulating progenitor cells (CPCs) are markers of overall vascular health and diminished levels have been associated with decreased reparative potential and worse outcomes. We assessed the short-term change in CPC levels following a single lipoprotein apheresis session in FH patients who are already on stable lipoprotein apheresis therapy. We hypothesized that in addition to a reduction in atherogenic lipids, the cardiovascular benefit from lipoprotein apheresis therapy is mediated by enhanced vascular reparative capacity through mobilization of CPCs. METHODS: Eight FH patients (1 homozygous and 7 heterozygous) on stable lipoprotein apheresis therapy for at least three months had CPCs measured at baseline (prior to apheresis) and two hours after apheresis. Results were compared with data from age-matched hyperlipidemic (HLP) patients on statin therapy and healthy volunteers. RESULTS: FH patients had higher baseline circulating levels of CD34+/CD133+ and CD34+/CD133+/CXCR4+ cells compared to HLP and healthy subjects. There was no significant change in CPCs after apheresis in FH patients. CONCLUSIONS: FH patients had higher CPC counts at baseline compared to age-matched HLP and healthy controls, suggesting activation of reparative mechanism in this high risk population. Larger studies are needed to better characterize differences in CPC counts between FH subjects and HLP patients over time.

Impact of early CMV reactivation in cord blood stem cell recipients in the current era.

Several studies have reported an association between CMV reactivation and a decreased incidence of relapse for AML after adult donor allogeneic hematopoietic cell transplantation (HCT). Limited data, however, are available on the impact of CMV reactivation on relapse after cord blood (CB) stem cell transplantation. The unique combination of higher incidence of CMV reactivation in the seropositive recipient and lower incidence of graft versus host disease (GvHD) in CB HCT permits a valuable design to analyze the impact of CMV reactivation. Data from 1684 patients transplanted with CB between 2003 and 2010 for AML and ALL were analyzed. The median time to CMV reactivation was 34 days (range: 2-287). CMV reactivation and positive CMV serology were associated with increased non-relapse mortality (NRM) among both AML and ALL CB recipients (reactivation, AML: relative risk (RR) 1.41 (1.07-1.85); ALL: 1.60 (1.14-2.23); Serology, AML: RR 1.39 (1.05-1.85), ALL: RR 1.61 (1.18-2.19)). For patients with ALL, but not those with AML, this yielded inferior overall survival (P<0.005). Risk of relapse was not influenced by CMV reactivation or positive CMV serostatus for either disease.

Plasmacytoid dendritic cells in allogeneic hematopoietic cell transplantation: benefit or burden?

Plasmacytoid dendritic cells (pDCs) bridge innate and adaptive immune responses and have important roles in hematopoietic engraftment, GvHD and graft-versus-leukemia responses following allogeneic hematopoietic cell transplantation (HCT). In addition, pDCs mediate antiviral immunity, particularly as they are the body's primary cellular source of type I interferon. Given their pleiotropic roles, pDCs have emerged as cells that critically impact transplant outcomes, including overall survival. In this article, we will review the pre-clinical and clinical literature, supporting the crucial roles that pDCs assume as key immune effector cells during HCT.

Low blood lymphocyte count at 30 days post transplant predicts worse acute GVHD and survival but not relapse in a large retrospective cohort.

Multiple reports have shown that low absolute lymphocyte count at day 30 (ALC30) after allogeneic hematopoietic SCT (AHSCT) is associated with higher risk of disease relapse and worse OS. However, these reports included heterogeneous populations with different grafts and GVHD prophylaxis. Therefore, we retrospectively evaluated the association of ALC30 with transplant outcomes in a cohort of 381 consecutive patients who underwent AHSCT between 2005 and 2010 and received T-replete PBSC grafts and Tacrolimus/Mycophenolate combination as GVHD prophylaxis. Median follow-up was 57 months. Lower ALC30 (⩽400 × 10(6)/L) was associated with lower OS and increased nonrelapse mortality (NRM) for the whole cohort as well as for recipients of SD and UD grafts separately. Lower ALC30 was associated with more severe acute GVHD (aGVHD; III-IV) for the entire cohort as well as for the SD and UD groups. No association was found between lower ALC30 and relapse. Pretransplant factors associated with lower ALC30 were: unrelated donors; HLA mismatch; older donors; lower recipient age; and lower CD34+ cell dose. In this large retrospective study, ALC30⩽400 × 10(6)/L was associated with worse OS, increased NRM and severe aGVHD.

Risk associations between HLA-DPB1 T-cell epitope matching and outcome of unrelated hematopoietic cell transplantation are independent of HLA-DPA1.

HLA-DP antigens are beta-alpha heterodimers encoded by polymorphic HLA-DPB1 and -DPA1 alleles, respectively, in strong linkage disequilibrium (LD) with each other. Non-permissive unrelated donor (UD)-recipient HLA-DPB1 mismatches across three different T-cell epitope (TCE) groups are associated with increased mortality after hematopoietic SCT (HCT), but the role of HLA-DPA1 is unclear. We studied 1281 onco-hematologic patients after 10/10 HLA-matched UD-HCT facilitated by the National Marrow Donor Program. Non-permissive mismatches defined solely by HLA-DPB1 TCE groups were associated with significantly higher risks of TRM compared to permissive mismatches (hazard ratio (HR) 1.30, confidence interval (CI) 1.06-1.53; P=0.009) or allele matches. Moreover, non-permissive HLA-DPB1 TCE group mismatches in the graft versus host (GvH) direction significantly decreased the risk of relapse compared to permissive mismatches (HR 0.55, CI 0.37-0.80; P=0.002) or allele matches. Splitting each group into HLA-DPA1*02:01 positive or negative, in frequent LD with HLA-DPB1 alleles from two of the three TCE groups, or into HLA-DPA1 matched or mismatched, did not significantly alter the observed risk associations. Our findings suggest that the effects of clinically non-permissive HLA-DPB1 TCE group mismatches are independent of HLA-DPA1, and that selection of donors with non-permissive DPB1 TCE mismatches in GvH direction might provide some protection from disease recurrence.

Ph+ ALL patients in first complete remission have similar survival after reduced intensity and myeloablative allogeneic transplantation: impact of tyrosine kinase inhibitor and minimal residual disease.

The efficacy of reduced intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (HCT) for Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) is uncertain. We analyzed 197 adults with Ph+ ALL in first complete remission; 67 patients receiving RIC were matched with 130 receiving myeloablative conditioning (MAC) for age, donor type and HCT year. Over 75% received pre-HCT tyrosine kinase inhibitors (TKIs), mostly imatinib; 39% (RIC) and 49% (MAC) were minimal residual disease (MRD)(neg) pre-HCT. At a median 4.5 years follow-up, 1-year transplant-related mortality (TRM) was lower in RIC (13%) than MAC (36%; P=0.001) while the 3-year relapse rate was 49% in RIC and 28% in MAC (P=0.058). Overall survival (OS) was similar (RIC 39% (95% confidence interval (CI) 27-52) vs 35% (95% CI 27-44); P=0.62). Patients MRD(pos) pre-HCT had higher risk of relapse with RIC vs MAC (hazard ratio (HR) 1.97; P=0.026). However, patients receiving pre-HCT TKI in combination with MRD negativity pre-RIC HCT had superior OS (55%) compared with a similar MRD population after MAC (33%; P=0.0042). In multivariate analysis, RIC lowered TRM (HR 0.6; P=0.057), but absence of pre-HCT TKI (HR 1.88; P=0.018), RIC (HR 1.891; P=0.054) and pre-HCT MRD(pos) (HR 1.6; P=0.070) increased relapse risk. RIC is a valid alternative strategy for Ph+ ALL patients ineligible for MAC and MRD(neg) status is preferred pre-HCT.

Favorable impact of pre-transplant ATG on outcomes of reduced-intensity hematopoietic cell transplants from partially mismatched unrelated donors.

Reduced-intensity conditioning (RIC) permits allogeneic hematopoietic progenitor cell transplantation in patients who would not be considered candidates for transplantation using a myeloablative preparative regimen because of age, comorbidities or prior therapy. In the setting of myeloablative transplantation, use of antithymocyte globulin (ATG) can reduce the risk of GVHD without negatively affecting transplant outcomes; however, limited data exist on the impact of ATG in the setting of RIC, particularly when there is HLA-mismatch. We performed a retrospective analysis of 85 patients who received unrelated donor transplants at our institution for hematologic malignancies following conditioning with fludarabine and melphalan (FluMel), with or without rabbit ATG (6 mg/kg). ATG was targeted to patients receiving HLA-mismatched grafts. With a median follow-up of 36 months, those receiving ATG and a mismatched graft had similar rates of acute and chronic GVHD, relapse, and similar OS compared with those receiving HLA-matched grafts without ATG. In a multivariate analysis, HLA-mismatched donor was not associated with a decrement in OS. We conclude that this intermediate dose of ATG is effective in preventing severe GVHD in the setting of HLA-mismatch, without undue compromise of the graft versus tumor effects on which RIC transplants depend.

Palifermin for the reduction of acute GVHD: a randomized, double-blind, placebo-controlled trial.

This prospective, randomized, double-blind, placebo-controlled study evaluated the efficacy of palifermin to reduce the incidence of severe (grade 3-4) acute GVHD after myeloablation and allo-SCT. Adults who received allo-SCT for hematologic malignancies received placebo or palifermin 60 µg/kg daily on three consecutive days before conditioning and a single dose of 180 µg/kg after conditioning, but often 1 or 2 days before allo-SCT. Subjects received MTX (plus CYA or tacrolimus) on days 1, 3, 6 and 11. Acute GVHD was evaluated once weekly and oral mucositis was evaluated daily. Subjects were randomly assigned to placebo (n=78) or palifermin (n=77). Conditioning included TBI in approximately half of the subjects (48% placebo, 51% palifermin). The primary efficacy end point, subject incidence of grade 3-4 acute GVHD, was similar between treatment groups (17% placebo, 16% palifermin). Grade 3-4 oral mucositis (73% placebo, 81% palifermin) and other secondary efficacy end points were similar between treatment groups. The most commonly reported treatment-related adverse events were skin/s.c. events such as rash, pruritus, and erythema. This exploratory study of acute GVHD after myeloablation and allo-SCT did not provide evidence of a treatment effect with this dosing regimen of palifermin.

Minor antigens on transfused RBCs crossprime CD8 T cells but do not induce full effector function.

HLA-matched bone marrow transplantation (BMT) is a cure for nonmalignant hematological disorders; however, rejection rates are high and correlate with the number of antecedent transfusions. Recently, using murine models, we reported that minor antigens (mHAs) in transfused leukoreduced red blood cell (RBC) or platelet units induce rejection of subsequent BMT. To study RBCs as an immunogen, we utilized transgenic donors that express a model mHA selectively on RBCs (HOD mouse). Transfusion of HOD blood did not induce BMT rejection of marrow that shared mHAs with the HOD RBCs. Similarly, no endogenous anti-HOD CD8(+) T-cell response was detected with antigen-specific tetramer reagents. Adoptively transferred OT-I T cells rapidly expanded after HOD blood transfusion; however, only a semi-effector phenotype was observed (tumor necrosis factor-α and interferon-γ secretion, but essentially no Granzyme B). After initial expansion, OT-I T cells contracted rapidly to very low levels. A similar trend was observed by in vivo CTL assay, with only transient lytic activity. Together, these data indicate that RBCs may not be the component of RBC units that induces BMT rejection, and suggest that contaminating platelets or leukocytes may be responsible.

A novel and simplified method of culture of human blood-derived early endothelial progenitor cells for the treatment of ischemic vascular disease.

Endothelial progenitor cells (EPCs) consist of two different subpopulations named early (eEPCs) and late EPCs (lEPCs) that are derived from CD14(+) and CD14(-) circulating cells, respectively. These cells are regularly cultured over fibronectin-coated surfaces in endothelial basal medium (EBM)-2 supplemented with insulin-like growth factor (IGF-1), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and fibroblast growth factor (FGF). We have developed a new and simplified method for culturing human EPCs obtained from peripheral blood and tested their ability to preserve cardiac function following infarction. We first demonstrated that eEPCs derived from human peripheral blood mononuclear cells (PBMCs) and cultured in EBM-2 medium supplemented with autologous serum (10%) over fibronectin-coated surfaces (10 µg/ml) in the presence of IGF-1 (50 ng/ml) only, have a secretome similar to eEPCs cultured under regular conditions with IGF-1, VEGF, EGF, and FGF. Our data also indicate that IGF-1 modulates PBMC secretome in a dose-dependent manner. In another series of experiments, we showed that PBMCs cultured in suspension in bags (S-PBMCs) in basal medium supplemented with fibronectin and IGF-1 secrete significant amounts of stem cell factor (SCF, 31.3 ± 3.1 pg/ml)), hepatocyte growth factor (HGF, 438.6 ± 41.4 pg/ml), soluble tumor necrosis factor receptor 1 (sTNFR1, 127.1 ± 9.9 pg/ml), VEGF (139.3 ± 9.6 pg/ml), and IGF-1 (147.2 ± 46.1 pg/ml) but very low levels of TNF-α (13.4 ± 2.5 pg/ml). S-PBMCs injected intravenously into NOD SCID mice migrated to the injured myocardium, reduced cardiac fibrosis, enhanced angiogenesis, and preserved cardiac function after myocardial infarction (MI) in a manner similar to eEPCs cultured under standard conditions. In conclusion, we show in this study a refined and optimized method for culturing eEPCs. Our data indicate that S-PBMCs are composed of several cell populations including eEPCs and that they secrete high amounts of antiapoptotic, anti-inflammatory, and proangiogenic factors capable of preserving cardiac function following MI.

Eosinophilic pulmonary syndrome as a manifestation of GVHD following hematopoietic stem cell transplantation in three patients.

Eosinophilic pulmonary syndrome is an uncommon problem in SCT recipients that can mimic an infectious process. We report the occurrence of eosinophilic pulmonary syndrome in three patients following allogeneic hematopoietic stem cell transplantation (HSCT), and postulate that this entity is part of the clinicopathologic spectrum of pulmonary GVHD. In all three cases, active chronic GVHD of the skin preceded or coincided with the development of pulmonary involvement. Other common features included peripheral blood eosinophilia, diffuse bilateral pulmonary infiltrates and lung biopsies showing pronounced infiltrates of eosinophils involving the small bronchioles. All patients responded promptly to systemic steroid therapy, with improvement of their pulmonary symptoms and the resolution of peripheral blood eosinophilia. Clinicians should be aware that eosinophilic pulmonary syndrome can occur following HSCT, may be associated with other manifestations of chronic GVHD, and generally responds well to corticosteroid therapy.

Long-term progression-free survival after early autologous transplantation for mantle-cell lymphoma.

Autologous hematopoietic progenitor SCT (HPCT) has been studied both as a consolidative and salvage maneuver in mantle-cell lymphoma (MCL), and may improve failure-free survival rates as well as overall survival. We describe 21 patients with MCL who received autologous HPCT at Emory University Hospital as part of the primary treatment strategy. Sixteen patients were in CR1 and five in PR1 at the time of HPCT. The most commonly used induction chemotherapy was the hyper-CVAD (cyclophosphamide, vincristine, doxorubicin and dexamethasone) regimen with or without rituximab. At the last follow-up, 17 patients were in continuous CR, and there were four relapses. There were no transplant-related deaths. With a median follow-up of 54 months from HPCT, 5-year progression-free survival and overall survival are 73% and 76%, respectively. Our retrospective analysis provides the longest follow-up to date for patients with MCL who received an autologous HPCT as part of primary treatment. This lengthy follow-up helps define the natural course of MCL after autologous transplantation.

Lipid formulations of amphotericin B preserve and stabilize renal function in HSCT recipients.

The current study assessed renal function based on medical records in adult hematopoietic stem cell transplant (HSCT) recipients with proven or probable invasive fungal infection (IFI) transplanted between 1995 and 2000. We confirm that amphotericin B deoxycholate (AmB-d) is nephrotoxic in a large percentage of HSCT recipients. Due to nephrotoxicity, defined as serum creatinine (SCr) >2.5 mg/dl or a 100% increase in SCr from baseline, 88% of patients treated with AmB-d were switched to a lipid formulation of amphotericin B (LFAB). In total, 53% of patients initiated on AmB-d were switched within the first week of therapy. Significantly more patients (70.6%) treated with AmB-d experienced a 100% increase in SCr from baseline compared to patients treated with either AmBisome (44.4%) or Abelcet (41.2%). A Cox Proportional Hazards Model revealed that, compared to patients initiated on AmBisome or Abelcet, the risk of nephrotoxicity (RR=1.5 vs AmBisome; RR=1.7 vs Abelcet), dialysis (RR=2.4 vs AmBisome; RR=1.4 vs Abelcet), and death (RR=2.0 vs AmBisome; RR=1.1 vs Abelcet) were all increased for patients initiated on AmB-d. Study results suggest that renal function improves and mortality declines when an LFAB is given to HSCT patients as initial therapy rather than as second-line therapy, the current practice.

Generation of alloreactive anti-leukemic cytotoxic T lymphocytes with attenuated GVHD properties from haploidentical parents in childhood acute lymphoblastic leukemia.

We sought to generate alloreactive leukemia-reactive cytotoxic T lymphocytes from haploidentical parents by culture of peripheral blood mononuclear cells in vitro with irradiated leukemic blasts and IL-2 from children with ALL. After 21 days in culture the mean cytotoxicity of haploidentical lymphocytes against ALL blasts was 38% (n = 11). Cultured parental CTL were not leukemia specific but alloreactive as evidenced by equivalent cytotoxicity against stimulating ALL blasts and ConA-stimulated blasts from the other parent. The cultures yielded primarily CD8(+) T cells (59%). Irradiation of CTL limited proliferation by 96% but had no short-term effects on leukemia reactive cytotoxicity, suggesting a means to limit GVHD potential in vivo. One patient was treated for relapse of ALL post-haploidentical transplant with CTL generated from the original donor. A total of nine infusions were given: the first three were irradiated, while the last six were not due to disease progression. The patient experienced clearance of peripheral blasts, and despite concomitant infusion of IL-2 with the last three CTL infusions, did not experience immediate GVHD reactions. We conclude that ALL blasts are sufficiently immunostimulatory to generate in vitro CTL with provision of exogenous IL-2, and that these CTL could exert an anti-leukemia effect in vivo.