Clinical Significance of Haplo-Fever and Cytokine Profiling After Graft Infusion in Allogeneic Stem Cell Transplantation From Haplo-Identical Donors

The degree of HLA matching determines the incidence of cytokine release syndrome and associated nonrelapse mortality in matched related and unrelated allogeneic stem cell transplantation with post-transplant cyclophosphamide

Cytokine release syndrome (CRS) occurs frequently after haplo-identical allogeneic stem cell transplantation (alloSCT) with post-transplant cyclophosphamide (PTCy), increasing nonrelapse mortality (NRM) and decreasing survival. Data on CRS in HLA-matched alloSCT are limited and effects of specific HLA-mismatches on CRS development unknown. We hypothesized that in HLA-matched alloSCT increasing degrees of HLA-mismatching influence CRS incidence, NRM and survival. Retrospective analysis of 126 HLA-matched PTCy-alloSCT patients showed that higher degrees of HLA-mismatching significantly increased CRS incidence (26%, 75% and 90% CRS with 12/12, 10/10 and 9/10 matched donors, respectively). Maximum temperature during CRS increased with higher HLA-mismatch. Specific associations between HLA-mismatches and CRS could be determined. Grade 2 CRS and CRS-induced grade 3 fever were associated with significantly increased NRM (p < 0.001 and p = 0.003, respectively) and inferior survival (p < 0.001 and p = 0.005, respectively). NRM was mainly caused by disease conditions that may be considered CRS-induced inflammatory responses (encephalopathy, cryptogenic organizing pneumonia and multi-organ failure).

Post-transplant cyclophosphamide at 80 mg/kg with low dose post-engraftment anti-thymocyte globulin in haploidentical transplantation with myeloablative conditioning

While post-transplant cyclophosphamide (PTCy) is commonly used as graft-versus-host disease (GvHD) prophylaxis in haploidentical stem cell transplantation (haplo-HSCT), its dose remains a matter of debate due to side effect concerns. Standard dose of 100 mg/kg associated with tacrolimus and post-engraftment anti-thymocyte globulin (ATG) was used as the reference GvHD prophylaxis in our center and had demonstrated encouraging results. Though PTCy 80 mg/kg was shown to be feasible in patients in reduced-intensity conditioning, whether it exerts equivalent GvHD prophylactic efficacy in myeloablative conditioning (MAC) setting has not been confirmed. Here, we retrospectively analyzed the efficacy and safety of PTCy 80 mg/kg combined with tacrolimus and post-engraftment ATG as GvHD prophylaxis in patients aged more than 55 years or with cardiac antecedents or HCT-CI score >2 undergoing haplo-HSCT with MAC. The cumulative incidence of grade III-IV aGvHD at day 100 and moderate-to-severe cGvHD at 1 year was 4.8% ± 3.4% and 19.9% ± 7.0%, respectively. When compared with patients receiving the reference regimen, patients from the PTCy 80 mg/kg group had similar incidence of GvHDs and survival as their younger counterparts. Thus, PTCy 80 mg/kg seems to be feasible for patients treated with MAC conditioning regimens in haplo-HSCT, inviting further investigation notably in frail patients.

A uniform conditioning regimen of busulfan, fludarabine, and antithymocyte globulin for allogeneic haematopoietic cell transplantation from haploidentical family, matched sibling, or unrelated donors-A single-centre, prospective, explorative study

In a prospective, explorative study, the donor-source difference of haploidentical family (HF), matched sibling (MS), and unrelated donors (UD) was evaluated for the outcome of haematopoietic cell transplantations (HCT) in 101 patients with acute myeloid leukaemia (AML) in complete remission (CR). To eliminate compounding effects, a uniform conditioning regimen containing antithymocyte globulin (ATG) was used. After transplantation, there was a significantly higher cumulative incidence of acute graft-versus-host disease (GVHD) in HF-HCT patients (49%, 7%, and 16% for HF-, MS- and UD-HCT respectively; p < 0.001). A quarter of acute GVHD cases observed in HF-HCT patients occurred within three days of engraftment and were characterized by diffuse skin rash, fever, weight gain, and hypoalbuminaemia. This peri-engraftment acute GVHD was not observed in MS-HCT or UD-HCT patients. Additionally, a significantly higher proportion of HF-HCT patients achieved complete donor chimaerism in the peripheral mononuclear cells at one month (88%, 46%, and 69% for HF-, MS- and UD-HCT respectively; p = 0.001). There was no significant difference in engraftment, chronic GVHD, leukaemia recurrence, non-relapse mortality, and patient survival. In patients with AML in CR who received HCT using ATG-containing conditioning, stronger donor-patient alloreactivity was observed in HF-HCT, in terms of increased acute GVHD and higher likelihood of complete donor chimaerism.