Pretransplantation vitamin A plasma levels and risk of acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation

From support to therapy: rethinking the role of nutrition in acute graft-versus-host disease

Allogeneic Hematopoietic stem cell transplantation (HSCT) offers a potential cure for patients with hematologic malignancies. Unfortunately, graft-versus-host disease (GVHD) remains a major obstacle to the greater success of this treatment. Despite intensive research efforts over the past several decades, GVHD is still a major cause of morbidity and mortality in patients receiving allogeneic HSCT. The genetic disparity between donor and recipient is the primary factor that dictates the extent of alloimmune response and the severity of acute GVHD (aGVHD). However, some nongenetic factors are also actively involved in GVHD pathogenesis. Thus, identifying host factors that can be readily modified to reduce GVHD risk is of important clinical significance. We are particularly interested in the potential role of nutrition, as a nongenetic factor, in the etiology and management of aGVHD. In this article, we summarize recent findings regarding how different routes of nutritional support and various dietary factors affect aGVHD. Since diet is one of the most important factors that shape gut microbiota, we also provide evidence for a potential link between certain nutrients and gut microbiota in recipients of allogeneic HSCT. We propose a shifting role of nutrition from support to therapy in GVHD by targeting gut microbiota.

Retinoic Acid Signaling Modulates Recipient Gut Barrier Integrity and Microbiota After Allogeneic Hematopoietic Stem Cell Transplantation in Mice

Graft-versus-host disease (GVHD) remains a major complication after allogeneic hematopoietic stem cell transplantation (HSCT). An impaired intestinal epithelial barrier is an important component of GVHD pathogenesis. However, contributing host factors that modulate mucosal barrier integrity during GVHD are poorly defined. We hypothesized that vitamin A and retinoic acid (RA) exert positive impacts on maintaining intestinal barrier function after HSCT, thus preventing or dampening GVHD severity. Unexpectedly, we found that exogenous RA increased intestinal permeability of recipient mice after allogeneic HSCT. Serum bacterial endotoxin levels were significantly higher in GVHD mice fed a vitamin A-high (VAH) diet compared to those fed a vitamin A-normal (VAN) diet, indicating a more compromised intestinal barrier function. Furthermore, VAH mice showed more severe lung GVHD with increased donor T cell infiltration in this tissue and died significantly faster than VAN recipients. 16S rRNA sequencing of fecal samples revealed significant differences in the diversity and composition of gut microbiota between VAN and VAH transplant recipients. Collectively, we show that retinoic acid signaling may negatively impact intestinal barrier function during GVHD. Mild vitamin A supplementation is associated with increased lung GVHD and more profound gut dysbiosis. Micronutrients such as vitamin A could modulate complications of allogeneic HSCT, which may be mediated by shaping gut microbiota.

Pre-transplantation plasma vitamin D levels and acute graft-versus-host disease after myeloablative hematopoietic cell transplantation in adults

BACKGROUND

The association between vitamin D and acute graft-versus-host disease (GvHD) remains controversial, especially for patients receiving myeloablative conditioning.

METHODS

We measured pre-transplantation plasma vitamin D (25-hydroxyvitamin D₃ + D₂) levels by competitive electrochemiluminescence in plasma samples from 116 adult patients who underwent a myeloablative allogeneic transplantation at Rigshospitalet, Copenhagen between July 2015 and August 2018.

RESULTS

The median (Q1, Q3) pre-transplantation plasma vitamin D level was 64 (47, 85) nmol/L (normal range: 50-160 nmol/L). Vitamin D insufficiency (<50 nmol/L) and moderate deficiency (<25 nmol/L) were observed in 29% and 8% of patients, respectively. No patients had a severe deficiency (<12 nmol/L). Pre-transplantation vitamin D levels were slightly higher in patients who later developed grade II-IV acute GvHD (mean difference: 8.1 nmol/L), but the 95% confidence interval [CI] encompassed clinically insignificant differences (CI: -2.2, 19.2 nmol/L). From multivariable logistic regression, we found that a patient with a pre-transplantation vitamin D level of 85 nmol/L (Q3) had 1.5 times higher odds of grade II-IV acute GvHD than a patient with a level of 47 nmol/L (Q1; CI of odds ratio: 0.84, 2.7; adjusted for patient age, donor type, use of anti-thymocyte globulin, and use of 12 Gy total-body irradiation). Patients with pre-transplantation vitamin D insufficiency (N = 34) had a cumulative incidence of grade II-IV acute GvHD similar to that of patients with vitamin D sufficiency (26% [CI: 11%, 42%] versus 35% [CI: 25%, 46%], respectively).

CONCLUSIONS

Our data did not support an association between pre-transplantation vitamin D levels or vitamin D insufficiency and acute GvHD in adult patients receiving myeloablative conditioning.

Vitamin E and acute graft-versus-host disease after myeloablative allogeneic hematopoietic cell transplantation

OBJECTIVES

Vitamin E has antioxidant and immunomodulatory effects that might influence the development of acute graft-versus-host disease (GvHD). We investigated the association between plasma vitamin E levels and acute GvHD.

METHODS

We studied 115 adults who underwent myeloablative allogeneic hematopoietic cell transplantation between July 2015 and August 2018. Vitamin E was measured by high-performance liquid chromatography in stored plasma samples obtained pre-transplantation at day -23 (±15 days) and post-transplantation at day +28 (±3 days).

RESULTS

Pre-transplantation vitamin E levels were inversely associated with grade II-IV acute GvHD (hazard ratio 0.68 per 10 µmol/L increase, 95% confidence interval [CI]: 0.47-0.98). The association remained after adjustment for known prognostic factors for acute GvHD. Patients with levels below the median had a cumulative incidence of grade II-IV acute GvHD of 46% (CI: 33-59%) versus 21% (CI: 10-32%) in patients with levels above the median. No clear association with non-relapse mortality, relapse, or chronic GvHD was found. Post-transplantation vitamin E levels (measured in 72 [63%] patients) were correlated with pre-transplantation levels (ρ = .31) but were not associated with subsequent grade II-IV acute GvHD.

CONCLUSIONS

High pre-transplantation vitamin E levels were associated with less acute GvHD.

Effect of vitamin A on intestinal mucosal injury in pediatric patients receiving hematopoietic stem cell transplantation and chemotherapy: a quasai-randomized trial

Objective

Vitamin A is involved in maintenance of gut mucosal integrity and normal immune function. However, it is unclear whether these functions of vitamin A have any beneficial effects in patients undergoing hematopoietic stem cell transplantation (HSCT). In this study, we aimed to examine the potential protective effect of vitamin A supplementation on gastrointestinal (GI) mucosal integrity in HSCT recipients using plasma citrulline as a surrogate marker of intestinal integrity.

Results

We performed a quasi-randomized trial in 30 pediatric patients undergoing HSCT. Half (n = 15) of the patients received a single high dose of vitamin A (200,000 IU) before the conditioning regimen was given, and half (n = 15) did not. Clinical data of patients who developed post-transplant complications were recorded for 60 days after HSCT. There were no significant differences in mean plasma citrulline levels on day 7 after HSCT between the treatment and control groups (5.8 vs. 5.9 µmol/L, respectively). The incidence of mucositis and other complications were not different between the two groups within 60 days of HSCT. Vitamin A supplementation prior to HSCT in pediatric patients had no clinical benefit in protecting GI mucosal integrity.