Antithymocyte Globulin for Graft-Versus-Host Disease Prophylaxis After Allogeneic Hematopoietic Stem-Cell Transplantation

Impact of anti-thymocyte globulin dose for graft-versus-host disease prophylaxis in allogeneic hematopoietic cell transplantation from matched unrelated donors: a multicenter experience

Despite the widespread use of rabbit anti-thymocyte globulin (ATG) to prevent acute and chronic graft-versus-host disease (aGVHD, cGVHD) after allogeneic hematopoietic cell transplantation (allo-HCT), convincing evidence about an optimal dose is lacking. We retrospectively evaluated the clinical impact of two different ATG doses (5 vs 6-7.5 mg/kg) in 395 adult patients undergoing HSCT from matched unrelated donors (MUD) at 3 Italian centers. Cumulative incidence of aGVHD and moderate-severe cGVHD did not differ in the 2 groups. We observed a trend toward prolonged overall survival (OS) and disease-free survival (DFS) with lower ATG dose (5-year OS and DFS 56.6% vs. 46.3%, p=0.052, and 46.8% vs. 38.6%, p=0.051, respectively) and no differences in relapse incidence and non-relapse mortality. However, a significantly increased infection-related mortality (IRM) was observed in patients who received a higher ATG dose (16.7% vs. 8.8% in the lower ATG group, p=0.019). Besides, graft and relapse-free survival (GRFS) was superior in the lower ATG group (5-year GRFS 43.1% vs. 32.4%, p=0.014). The negative impact of higher ATG dose on IRM and GRFS was confirmed by multivariate analysis. Our results suggest that ATG doses higher than 5 mg/kg are not required for MUD allo-HCT and seem associated with worse outcomes.

Incidence and Risk Factors for Fatal Graft-versus-host Disease After Liver Transplantation

BACKGROUND

Graft-versus-host disease (GVHD) after liver transplantation (LT) is a rare but serious complication. The aim of this study is to identify risk factors, including immunosuppressive regimens, for mortality due to GVHD (fatal GVHD).

METHODS

Using data from the OPTN/UNOS registry, 77,416 adult patients who underwent LT between 2003 and 2018 were assessed. Risk factors for fatal GVHD were analyzed by focusing on induction and maintenance immunosuppression regimens.

RESULTS

The incidence of fatal GVHD was 0.2% (121/77,416), of whom 105 (87%) died within 180 days and 13 (11%) died between 181 days and 1 year. Median survival after LT was 68.0 (49.5-125.5) days. Recipient age minus donor age greater than 20 years (HR 2.57, P<0.001) and basiliximab induction (HR 1.69, P=0.018) were independent risk factors for fatal GVHD. Maintenance therapy with mycophenolate mofetil (MMF) was associated with a decrease in fatal GVHD (HR 0.51, P=0.001). In an increased risk cohort of patients with recipient-donor age discrepancy greater than 20 years, MMF use was associated with a 50% decline in fatal GVHD (HR 0.50, P<0.001).

CONCLUSIONS

Recipient age minus donor age greater than 20 years remains a significant risk factor for fatal GVHD. The risk of fatal GVHD significantly increases in association with basiliximab induction and decreases with MMF maintenance. These associations were pronounced in patients with recipient minus donor age greater than 20 years. These results emphasize the importance of donor age and individualized immunosuppression regimens on the risk of fatal GVHD.

Outcomes of chronic graft-versus-host disease following matched sibling donor versus umbilical cord blood transplant

We compared chronic graft-versus-host disease (cGvHD) following umbilical cord blood (UCBT) and matched sibling donor peripheral blood transplant (MSD). 145 patients (2010-2017) with cGvHD after MSD (n = 104) and UCBT (n = 41) were included. Prior acute GvHD was less frequent in MSD (55% vs. 85%; p = 0.01). Severe cGvHD (32% vs. 15%, p = 0.01) and de-novo onset (45% vs. 15%, p < 0.01) were more frequent following MSD. Liver was more frequently involved in MSD recipients (38% vs. 6%); and GI in UCBT (33% vs. 63%), both p < 0.01. Overall response (CR + PR) was similar between both cohorts. 2-year CR was higher in UCBT (14% vs 33%, p = 0.02). Karnofsky score (KPS) ≥ 90 at cGvHD diagnosis was associated with higher odds of response (95%CI: 1.42-10, p < 0.01). The cumulative incidence of durable discontinuation of immune-suppressive therapy, failure-free survival (FFS) and NRM at 2-years were similar between cohorts. KPS < 90 (95%CI: 3.1-24.9, p < 0.01) and platelets <100 × 10e9/L (95%CI: 1.25-10, p = 0.01) were associated with higher risk of NRM. UCBT patients were more likely to have a prior acute GvHD, less severe cGvHD and more likely to attain CR. Despite differences, both cohorts had similar NRM and FFS. High-risk groups, including those with platelets <100 × 10e9/L and KPS < 90, need careful monitoring and intensified therapy.

Anti-thymocyte globulin in haematology: Recent developments

Anti-thymocyte globulin (ATG) is a polyclonal antiserum introduced into clinical medicine more than 30 years ago. It induces a broad non-specific immunosuppression. In haematology, standard indications are severe aplastic anaemia and prophylaxis and treatment of graft-versus-host disease (GVHD) (after allogeneic transplantation). For aplastic anaemia, ATG from horses has been found to be superior to ATG from rabbits. In the situation of allogeneic transplantation, ATG lessens the risk of chronic GVHD but may not improve survival. There is current controversy regarding which patients benefit most from ATG and what the ideal dosage is. It is likely that in the coming years a more specific immunosuppressive will be developed that will minimize GVHD while maintaining the graft-versus-malignancy effect.

Optimizing anti-T-lymphocyte globulin dosing to improve long-term outcome after unrelated hematopoietic cell transplantation for hematologic malignancies

Prophylaxis of graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HCT) remains challenging. Because prospective randomized trials of in-vivo T cell depletion using anti-T-lymphocyte globulin (ATLG) in addition to a calcineurin inhibitor and methotrexate (MTX) led to conflicting outcome results, we evaluated the impact of ATLG on clinical outcome, lymphocyte- and immune reconstitution survival models. In total, 1500 consecutive patients with hematologic malignancies received matched unrelated donor (MUD) HCT with cyclosporin and MTX (N = 723, 48%) or with additional ATLG (N = 777, 52%). In the ATLG cohort, grades III-IV acute (12% vs 23%) and extensive chronic GVHD (18% vs 34%) incidences were significantly reduced (P < .0001). Nonrelapse mortality (27% vs 45%) and relapse (30% vs 22%) differed also significantly. Event-free and overall survival estimates at 10 years were 44% and 51% with ATLG and 33% and 35% without ATLG (P < .002 and <.0001). A dose-dependent ATLG effect on lymphocyte- and neutrophil reconstitution was observed. At ATLG exposure, lymphocyte counts and survival associated through a logarithmically increasing function. In this survival model, the lymphocyte count optimum range at exposure was between 0.4 and 1.45/nL (P = .001). This study supports additional ATLG immune prophylaxis and is the first study to associate optimal lymphocyte counts with survival after MUD-HCT.

Ex vivo and in vivo T cell-depleted allogeneic stem cell transplantation in patients with acute myeloid leukemia in first complete remission resulted in similar overall survival: on behalf of the ALWP of the EBMT and the MSKCC

Background

Graft-versus-host disease (GVHD) is one of the leading causes of non-relapse mortality and morbidity after allogeneic hematopoietic stem cell transplantation (allo-HCT).

Methods

We evaluated the outcomes of two well-established strategies used for GVHD prevention: in vivo T cell depletion using antithymocyte globulin (ATG) and ex vivo T cell depletion using a CD34-selected (CD34+) graft. A total of 525 adult patients (363 ATG, 162 CD34+) with intermediate or high-risk cytogenetics acute myeloid leukemia (AML) in first complete remission (CR1) were included. Patients underwent myeloablative allo-HCT using matched related or unrelated donors.

Results

Two-year overall survival estimate was 69.9% (95% CI, 58.5–69.4) in the ATG group and 67.6% (95% CI, 60.3–74.9) in the CD34+ group (p = 0.31). The cumulative incidence of grade II–IV acute GVHD and chronic GVHD was higher in the ATG cohort [HR 2.0 (95% CI 1.1–3.7), p = 0.02; HR 15.1 (95% CI 5.3–42.2), p < 0.0001]. Parameters associated with a lower GVHD-free relapse-free survival (GRFS) were ATG [HR 1.6 (95% CI 1.1–2.2), p = 0.006], adverse cytogenetic [HR 1.7 (95% CI 1.3–2.2), p = 0.0004], and the use of an unrelated donor [HR 1.4 (95% CI 1.0–1.9), p = 0.02]. There were no statistical differences between ATG and CD34+ in terms of relapse [HR 1.52 (95% CI 0.96–2.42), p = 0.07], non-relapse mortality [HR 0.96 (95% CI 0.54–1.74), p = 0.90], overall survival [HR 1.43 (95% CI 0.97–2.11), p = 0.07], and leukemia-free survival [HR 1.25 (95% CI 0.88–1.78), p = 0.21]. Significantly, more deaths related to infection occurred in the CD34+ group (16/52 vs. 19/112, p = 0.04).

Conclusions

These data suggest that both ex vivo CD34-selected and in vivo ATG T cell depletion are associated with a rather high OS and should be compared in a prospective randomized trial.

Electronic supplementary material

The online version of this article (10.1186/s13045-018-0668-3) contains supplementary material, which is available to authorized users.

A pilot study of single nucleotide polymorphisms in the interleukin-6 receptor and their effects on pre- and post-transplant serum mediator level and outcome after allogeneic stem cell transplantation

Interleukin (IL)-6 is an important regulator of immunity and inflammation in many diseases. Single nucleotide polymorphisms (SNPs) in the IL-6 gene influence outcome after allogeneic stem cell transplantation (ASCT), but the possible importance of SNPs in the IL-6 receptor has not been examined. We therefore investigated whether SNPs in the IL-6R gene influenced biochemical characteristics and clinical outcomes after ASCT. We examined the IL-6 promoter variant rs1800975 and the IL-6R SNPs rs4453032, rs2228145, rs4129267, rs4845374, rs4329505, rs4845617, rs12083537, rs4845618, rs6698040 and rs4379670 in a 101 population-based cohort of allotransplant recipients and their family donors. Patients being homozygous for the major alleles of the IL-6R SNPs rs2228145 and rs4845618 showed high pretransplant CRP serum levels together with decreased sIL-6R levels; the decreased IL-6R levels persisted 6 months post-transplant. In contrast, patients being homozygous for the minor allele of the IL-6R SNP rs4379670 showed decreased pretransplant CRP levels. Furthermore, the IL-6R rs4845618 donor genotype showed an association with severe acute graft-versus-host disease (GVHD), whereas the donor genotype of the IL-6 SNP rs1800795 was associated with decreased survival 100 days post-transplant. Finally, the recipient genotype of the IL-6R SNP rs4329505 showed a strong association with 2-years non-relapse mortality, and this effect was also highly significant in multivariate analysis. IL-6 and IL-6R SNPs influence the clinical outcome after allogeneic stem cell transplantation.