Treg/Tcon Immunotherapy and High Dose Marrow Irradiation Ensure Full Control of Leukemia Relapse in Haploidentical Transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is the most powerful therapy for patients with high risk of relapse. In spite of that, no matter the donor source or conditioning regimen used, leukemia relapse is still the leading cause of HSCT failure. In HLA-haploidentical HSCT, we recently applied a clinical protocol consisting of total body irradiation (TBI)-based conditioning regimen and a peripheral blood CD34+ cell graft combined with the adoptive transfer of naturally occurring regulatory T cells (Tregs) and conventional T cells (Tcons). No post-transplant pharmacologic GvHD prophylaxis was given. Such protocol was associated with low GvHD and relapse rate (Martelli et al., Blood 2014). To further reduce leukemia relapse in Treg/Tcon-based haploidentical HSCT (Treg/Tcon haplo-HSCT) we used high dose hyper-fractionated TBI (HF-TBI) in the conditioning regimen. We also extended Treg/Tcon haplo-HSCT to patients that are unfit (because of previous comorbidities) and/or too old to withstand high intensity regimens. In these patients the extra-hematologic toxicity of irradiation was reduced with the use of targeted total marrow and lymph node irradiation (TMLI). 40 patients with high risk acute leukemia (36 AML, 4 ALL) received Treg/Tcon haplo-HSCT. All but 3 patients were transplanted in complete remission. 12 younger patients (median age: 28, range: 20-43) received HF-TBI, while 28 older or unfit patients (59, 40-70) received TMLI in the conditioning regimen. HF-TBI (14.4 Gy) was administered in 12 fractions, 3 times a day for 4 days. TMLI was administered by means of Helical Tomotherapy HI-ART (9 fractions, 2 times a day for 4.5 days). Irradiation was followed by chemotherapy with Thiotepa, Fludarabine, and Cyclophosphamide. 2 × 106/kg freshly isolated CD4+CD25+FOXP3+ Tregs were transferred 4 days before the infusion of 1 × 106/kg Tcons and a mega-dose of CD34+ hematopoietic stem cells. No post-transplant pharmacologic GvHD prophylaxis was given. 38/40 patients engrafted. 12 (31%) developed aGvHD grade ³2 (10 are alive and off-therapy). 6 (16%) died because of transplant related complications (2 because of aGvHD, 2 infections, 1 veno-occlusive disease, 1 intracranial hemorrhage). Strikingly, despite the high risk diseases, no patient relapsed after a median follow up of 13 months (range 1-36, Fig. A). Further, only 1 patient developed cGvHD. Thus, cGvHD/Leukemia-free survival was 82% (Fig. B). Treg adoptive transfer allows for the safe infusion of an otherwise lethal dose of donor alloreactive Tcons in the absence of any other form of immune suppression. Our results demonstrate that the potent graft versus leukemia effect of Treg/Tcon adoptive transfer was boosted by high dose marrow irradiation. Thus, this study proves that the right combination of haploidentical Treg/Tcon immunotherapy plus a powerful conditioning regimen can fully eradicate leukemia

<it>Absidia Corymbifera </it>in an immune competent accident victim with multiple abdominal injuries: case report

Abstract Background We report a case of mucormycosis in a healthy 17-year-old accident victim with multiple abdominal injuries which was caused by infection with Absidia Corymbifera, a ubiquitous saphrophyte in the ground. Case presentation The patient was admitted to hospital with massive abdominal trauma. During an 8-hour emergency operation he received transfusions of compacted red blood cells, plasma, platelets and hemagel. He developed a crush syndrome with acute renal failure, resolved with extra-corporeal dialysis and had to undergo splenectomy because of spleen hematoma. As wound secretion and central venous catheter (CVC) blood cultures and drainage fluid were positive for Enterococcus Faecium, Providentia Rettgeri, Hafnia Alvei and Candida Albicans, tecoplanin, metronidazole, imipenem, and flucanozole were administered. Although the CVC was changed high fever persisted and discharge continued from the large abdominal wound. Repeated tampons in different sections and wound secretion smears were positive for A. corymbifera. Flucanozole was stopped and liposomal amphotericin (Ambisome; 5 mg/Kg i.v.) given for over 3 months. The patient improved; fever gradually disappeared. After 8 days, tampons and wound secretion smears were negative for A. corymbifera. No other fungal infections developed. Drainage fluid was later positive for tecoplanin-resistant E. faecium and Pseudomonas Aeroginosa responding only to meropenem and ciprofloxacin. Abdominal computerized tomography visualized fluid accumulation around the iliac-femoral bypass. Abcess was ruled out when scintigraphy showed no tracer uptake. The lesion was drained. Drainage fluid cultures were negative for bacteria and fungi. Fluid accumulation gradually disappeared with prolonged antibiotic and antifungal therapy. One year after the accident the patient is in good health, with normal quality of life. Conclusion Successful outcome was due to early, specific antifungal therapy, at sufficiently high dosage which was prolonged for an adequate period of time. Early diagnosis of mucormycosis is essential for efficacious anti-fungal treatment and prevention of irreversible spread of mucormycosis to vital organs. It presupposes awareness that A. corymbifera infection can develop in healthy individuals who are stressed and traumatized through skin-ground contact in accidents.</p

HUMAN T-HELPER CLONES INDUCE IGG PRODUCTION IN A SUBCLASS-SPECIFIC FASHION

The mechanisms governing the induction of IgG subclasses by T-helper cells in humans were investigated. As preliminary bulk-culture experiments had indicated that a direct B cell contact with viable T cells was an essential requirement for optimal IgG subclass production, 256 CD4+ human T cell clones were preactivated with PHA and cultured in direct contact with autologous B cells. These clones induced IgG production in a strikingly subclass-specific fashion. Moreover, the distribution of subclass-specific helper clones was very similar to the IgG subclass profile observed in serum and peripheral lymphoid tissue plasma cells (IgG1 approximately 60%, IgG2 approximately 30%, IgG3 approximately 5-10%, IgG4 less than or equal to 5%) and unlike that observed in resting B cells (which is IgG1 approximately 40% and IgG2 approximately 50%). It would, therefore, seem that a predominance of T cells capable of delivering IgG1-specific, as opposed to IgG2-specific, help is an essential factor for the preferential induction of IgG1 antibodies during B cell proliferation and differentiation. There was no relationship between IL2, IL4, IL6, and IFN-gamma secreted by the T-helper clones and their IgG subclass induction patterns. In addition, only a few supernatants were able to reproduce the helper effects of the clones themselves. Therefore, direct contact of B cells with helper clones is crucial for IgG-subclass production in humans

''Designed'' grafts for HLA-haploidentical stem cell transplantation

Today human leukocyte antigen-haploidentical transplantation is a feasible option for patients with high-risk acute leukemia who do not have matched donors. Whether it is T-cell replete or T-cell depleted, it is still, however, associated with issues of transplant-related mortality and posttrans-plant leukemia relapse. After reports that adoptive immunotherapy with T-regulatory cells controls the alloreactivityof conventional T lymphocytes in animal models, tomorrow’s world of haploidentical transplantation will focus on new “designed” grafts. They will contain an appropriate ratio of conventional T lymphocytes and T-regulatory cells, natural killer cells, gd T cells, and other accessory cells. Preliminary results of ongoing clinical trials show the approach is feasible. It is associated with better immune reconstitution and a quite powerful graft-versus-leukemia effect with a low incidence of graft-versus-host disease and no need for posttransplant pharmacological prophylaxis. Future strategies will focus on enhancing the clinical benefit of T-regulatory cells by increasing their number and strengthening their function

Quality of life and physicians' perception in myelodysplastic syndromes

: To detect factors associated with quality of life (QOL) of patients with myelodysplastic syndrome (MDS) and to compare the MDS patients' self-assessed QOL with that perceived by their physicians. In an observational, non-interventional, prospective, multicentre study, QOL was evaluated in 148 patients with newly diagnosed low- and intermediate-risk IPSS MDS. QOL measures (QOL-E v.2, LASA and EQ-5D) and patient-related candidate determinants of QOL were assessed for up to 18 months. Patients' QOL scores were compared with those obtained by appointed hematologists' assessment and with ECOG performance status (PS). Fatigue was not prevalent at diagnosis, though physical QOL and energy levels were low. Transfusion-dependent patients had worse QOL scores. In multivariate analysis, Hb levels and comorbidities were a major determinant of QOL. Physicians' perception of patients' well-being correlated with patients' QOL. Physicians underestimated the impact of disturbances on patients' QOL, mainly in the MDS-specific components. ECOG PS did not discriminate patients according to QOL status. In conclusion, the association of anemia with QOL is confirmed, while co-morbidities emerge as an independent predictor of QOL in MDS. Fatigue is not a major concern. ECOG PS is not a valuable surrogate of patient's QOL, thus highlighting that physician's judgment of patient's well-being must not substitute patient-reported outcomes. Appropriate questionnaires should be used to assess MDS patients' QOL in order to improve communication and therapeutic choice