Older recipient age is paradoxically associated with a lower incidence of chronic GVHD in thymoglobulin recipients: a retrospective study exploring risk factors for GVHD in allogeneic transplantation with thymoglobulin GVHD prophylaxis

Chronic liver disease after allogeneic hematopoietic cell transplantation

BACKGROUND AIMS

There are few descriptions of the epidemiology of chronic liver disease (CLD) after allogeneic hematopoietic stem cell transplantation (allo-HCT). Among those transplanted before 2000, viral hepatitis was the dominant cause of CLD. Recently, the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD, previously known as nonalcoholic fatty liver disease) is increasing in the general population. In addition, survivors of allo-HCT are known to be at increased risk of metabolic syndrome. We set out to describe the epidemiology of CLD in a modern cohort of allo-HCT recipients. We hypothesized that MASLD would be the most common cause of CLD in the cohort.

METHODS

We undertook a retrospective cohort and nested case-control study of 2-year survivors of allo-HCT in Alberta transplanted between 2008 and 2018.

RESULTS

Among 392 2-year survivors of allo-HCT between 2008 and 2018, the prevalence of CLD was 41.8% and MASLD was identified in 56% of those with CLD, followed by iron overload in 47% of those with CLD. The prevalence of MASLD among the entire cohort was 46%. Although most patients developed CLD before 2 years post-transplant, there was a 13% cumulative incidence of new CLD after 2 years posttransplant. Grade 2-4 acute graft-versus-host disease and/or moderate-to-severe chronic graft-versus-host disease and pretransplant CLD were strongly associated with CLD. In the case-control study examining the association between cardiovascular risk factors and CLD, type 2 diabetes was associated with CLD. Cirrhosis developed in 1.5% of survivors, and MASLD was an underlying etiology in one half of these cases. There was no difference in overall survival and non-relapse mortality between those who did and did not develop CLD.

CONCLUSIONS

MASLD is the main cause of CLD in recent long-term survivors of allo-HCT and may be associated with post-transplant corticosteroid exposure and type 2 diabetes. We note a shift in the underlying etiology of CLD post-HCT: previous studies describe viral hepatitis as the most common cause of CLD. The high prevalence of MASLD in allo-HCT recipients has important implications for survivorship care.

Characteristics and risk of chronic graft-versus-host disease of liver in allogeneic hematopoietic stem cell transplant recipients

Chronic graft-versus-host-disease (cGvHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Among various organ-specific cGvHD, the cGvHD of liver is less well-characterized. In this study, we applied the National Institutes of Health 2014 scoring criteria of cGvHD to analyze a retrospective cohort of 362 allo-HSCT recipients focusing on cGvHD of liver. The overall incidence of liver cGvHD with a score of 3 by 1.5 years post-transplant was 5.8% (21/362). Poor outcome, in terms of overall survival (OS), were observed in patients with scores of 3 liver cGvHD, comparing to those with scores less than 3 (hazard ratio [HR] 2.037, 95% confidence interval [CI] 1.123-3.696, P = 0.019). In multivariate analysis, male gender (HR 4.004, P = 0.042) and chronic hepatitis C virus (HCV) infection status (HR 19.087, P < 0.001) were statistically significant risk factors for scores of 3 liver cGvHD. Our results indicate that liver cGvHD with scores of 3 has a grave prognosis following allo-HSCT, and that HCV carrier status and male are risk factors. Early recognition of this devastating complication might help in prompt immunosuppressive therapy and reducing late poor outcome.

Donor-Recipient Matching for KIR Genotypes Reduces Chronic GVHD and Missing Inhibitory KIR Ligands Protect against Relapse after Myeloablative, HLA Matched Hematopoietic Cell Transplantation

BACKGROUND

Allogeneic hematopoietic cell transplantation (HCT) can be curative for many hematologic diseases. However, complications such as graft-versus-host disease (GVHD) and relapse of primary malignancy remain significant and are the leading causes of morbidity and mortality. Effects of killer Ig-like receptors (KIR)-influenced NK cells on HCT outcomes have been extensively pursued over the last decade. However, the relevance of the reported algorithms on HLA matched myeloablative HCT with rabbit antithymocyte globulin (ATG) is used for GVHD prophylaxis remains elusive. Here we examined the role of KIR and KIR-ligands of donor-recipient pairs in modifying the outcomes of ATG conditioned HLA matched sibling and unrelated donor HCT.

METHODS AND FINDINGS

The study cohort consisted of 281 HLA matched sibling and unrelated donor-recipient pairs of first allogeneic marrow or blood stem cell transplantation allocated into 'discovery' (135 pairs) and 'validation' (146 pairs) cohorts. High resolution HLA typing was obtained from the medical charts and KIR gene repertoires were obtained by a Luminex® based SSO method. All surviving patients were followed-up for a minimum of two years. KIR and HLA class I distributions of HCT pairs were stratified as per applicable definitions and were tested for their association with cause specific outcomes [acute GVHD grade II-IV (aGVHD), chronic GVHD needing systemic therapy (cGVHD) and relapse] using a multivariate competing risks regression model as well as with survival outcomes [relapse-free survival (RFS), cGVHD & relapse free survival (cGRFS) and overall survival (OS)] by multivariate Cox proportional hazards regression model. A significant association between KIR genotype mismatching (KIR-B/x donor into KIR-AA recipient or vice versa) and cGVHD was found in both discovery (p = 0.001; SHR = 2.78; 95%CI: 1.50-5.17) and validation cohorts (p = 0.005; SHR = 2.61; 95%CI: 1.33-5.11). High incidence of cGVHD associated with KIR genotype mismatching was applicable to both sibling and unrelated donors and was specific to recipients who had one or two C1 bearing HLA-C epitopes (HLA-C1/x, p = 0.001; SHR = 2.40; 95%CI: 1.42-4.06). When compared with KIR genotype mismatched transplants, HLA-C1/x patients receiving grafts from KIR genotype matched donors had a significantly improved cGRFS (p = 0.013; HR = 1.62; 95%CI: 1.11-2.39). Although there was no effect of KIR genotype matching on survival outcomes, a significantly reduced incidence of relapse (p = 0.001; SHR = 0.22; 95%CI: 0.10-0.54) and improved relapse-free survival (p = 0.038; HR = 0.40; 95%CI: 0.17-0.95) was observed with one or more missing ligands for donor inhibitory KIR among the recipients of unrelated donor transplants.

CONCLUSIONS

The present study for the first time presents the beneficial effects of KIR genotype matching in reducing cGVHD in myeloablative transplant setting using HLA matched (sibling and unrelated) donors. The findings offer a clinically applicable donor selection strategy that can help control cGVHD without affecting the risk of relapse and/or identify patients at a high risk of developing cGVHD as potential candidates for preemptive therapy. The findings also affirm the beneficial effect of one or more missing inhibitory KIR ligands in the recipient in reducing relapse and improving a relapse free survival in unrelated donor transplants.