Immunomodulatory effects of vitamin D: implications for GVHD

Age and vitamin D affect the magnitude of the antibody response to the first dose of the SARS-CoV-2 BNT162b2 vaccine

Background

Most approved vaccines utilise a two-dose strategy. To enable larger groups of patients to receive the first dose, the UK government increased the gap between the two doses from three to twelve weeks. Here we report on the immunogenicity of the first dose, including effect of age and vitamin D status on these levels over an 8 week-period.

Methods

Blood samples were collected from healthcare workers (HCW) receiving their first BNT162b2 vaccine dose between January and February 2021. Antibody (Ab) production was measured, prior to and weekly for 4 weeks post immunization, and a final measurement was performed at 8 weeks. Serum vitamin D concentrations were also measured at baseline.

Findings

Immunization of 97 HCW induced an Ab response that peaked 3•2 weeks post immunization to decrease thereafter. Ab levels remained positive at 8 weeks. IgG peak concentration was negatively associated with age (β=-0•440, p<0.001). Response to immunization was also significantly affected by vitamin D status (p=0•022), on average 29•3% greater peak value in individuals with 25(OH)D>50nmol/L. No other variable showed significant effect.

Interpretation

The first dose of BNT162b2 produced Ab levels that remained positive after 8 weeks. Peak was greater in younger subjects and 25(OH)D>50nmol/L was beneficial. Booster campaigns should take into consideration vitamin D status which is at its highest following a period of sunshine exposure or following oral supplementation (400-1000IU daily).

Funding

Abbott Diagnostics Ltd supplied the kits used to quantify the anti-SARS -CoV-2 Spike IgG and technical support as well as provided financial support for sample collections.

Vitamin D deficiency after allogeneic hematopoietic cell transplantation promotes T-cell activation and is inversely associated with an EZH2-ID3 signature

Vitamin D promotes a shift from a proinflammatory to a more tolerogenic immune state in allogeneic hematopoietic cell transplant (HCT) recipients. The dominant mechanism responsible for this shift has not been elucidated. We took a multifaceted approach to evaluating the clinical and immunologic impact of low vitamin D levels in 53 HCT recipients. We used 28-plex flow cytometry for immunophenotyping, serum cytokine levels, T-cell cytokine production, and T-cell whole genome transcription. The median day-30 vitamin D level was 20 ng/mL, and deficiency was common in younger patients undergoing myeloablative transplantation. Low vitamin D levels were associated with a high CD8/Treg ratio, increased serum levels and T-cell production of proinflammatory cytokines, and a gene expression signature of unrestrained T-cell proliferation and epigenetic modulation through the PRC2/EZH2 complex. Immunophenotyping confirmed a strong association between high levels of vitamin D and an activated EZH2 signature, characterized by overexpression of ID3, which has a role in effector T-cell differentiation. Our findings demonstrate the critical role of vitamin D in modulating T-cell function in human GVHD and identify a previously undescribed interaction with EZH2 and ID3, which may impact effector differentiation and has implications to cell therapies and other forms of cancer immunotherapy. © 20XX American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Impact of vitamin D level at diagnosis and transplantation on the prognosis of hematological malignancy: a meta-analysis

Vitamin D deficiency impairs prognosis in many types of cancer; however, its significance in each subtype of hematological malignancies is unclear. In addition, data on the association between pretransplant vitamin D levels and outcomes of hematopoietic stem cell transplantation (HSCT) are inconsistent. This systematic review and meta-analysis aimed to elucidate the impact of vitamin D levels at diagnosis or pre-HSCT on the prognosis of hematological malignancies. Thirty articles and abstracts were extracted from PubMed, Embase, and Cochrane Library databases and conference proceedings. Fixed and random effect models were used to analyze primary outcomes: overall survival (OS) and progression-free survival (PFS). Lower vitamin D level was significantly associated with poorer OS and PFS in myeloid malignancies (hazard ratio [HR], 1.39; 95% confidence interval [CI], 1.06-1.82 and HR, 2.03; 95% CI, 1.23-3.32, respectively) and lymphoid malignancies (HR, 2.07; 95% CI, 1.79-2.40 and HR, 1.91; 95% CI, 1.61-2.25, respectively), as well as outcomes for several lymphoma subtypes individually. Furthermore, a lower pretransplant vitamin D level was associated with poorer OS in autologous and allogeneic HSCT (HR, 1.65; 95% CI, 1.04-2.61 and HR, 1.50; 95% CI, 1.03-2.18, respectively). Despite the relatively small number of studies evaluated, these data suggest the importance of vitamin D status in outcomes of hematological malignancies (PROSPERO registration number: CRD42020205821).

Ultra-High Dose Vitamin D in Pediatric Hematopoietic Stem Cell Transplantation: A Nonrandomized Controlled Trial

Vitamin D is essential for bone health and has immunomodulatory properties. Most pediatric patients are vitamin D insufficient (<30 ng/mL) before hematopoietic stem cell transplantation (HSCT). Standard supplementation strategies fail to achieve vitamin D sufficiency in the acute post-transplantation period, and there are scarce data to support optimal vitamin D supplementation in this patient population. This study aimed to evaluate whether a single, oral, weight-based ultra-high dose of vitamin D (Stoss dosing) was more effective than standard supplementation to achieve pre-HSCT vitamin D sufficiency and reduce the incidence of HSCT-related complications (acute graft-versus-host disease, veno-occlusive disease, and/or transplant-associated thrombotic microangiopathy) that are associated with immune-mediated endothelial damage. Secondary endpoints examined the immunomodulatory properties of vitamin D. We conducted a nonrandomized controlled clinical trial of Stoss-dosed vitamin D in pediatric patients receiving HSCT. The study prospectively enrolled 33 patients, 29 of whom successfully received Stoss-dosed vitamin D and were compared to 136 patients in a historical control. Patient characteristics were compared using Fisher's exact test or t-test. The one-sided Fisher's exact test was used for cohort comparison of the primary endpoints. Logistic regression was used to examine the association between patient-specific factors and total 25-hydroxy vitamin D (25-OHD) levels and the compiled HSCT complications. In the Stoss cohort, 97% (n = 28/29) of patients achieved pre-HSCT vitamin D sufficiency compared to 67% (n = 10/15) of patients in the historical control who were on standard supplementation at the time the total 25-OHD level was assessed (P = .013). The mean total 25-OHD level in the Stoss cohort was significantly higher than patients in the historical control who received standard supplementation (72.2 ng/mL versus 35.8 ng/mL, P < .001). Nine patients in the Stoss cohort maintained vitamin D sufficiency throughout the first 100 days after HSCT, and the remaining 19 patients maintained sufficiency for a median of 63 days (range 6-105 days) from the Stoss dose. Patients receiving Stoss-dosed vitamin D developed a lower combined incidence of HSCT-related complications than the historical control (25% [n = 7/28] versus 42% [n = 57/136], P = .055). After Stoss dosing, immunophenotyping studies found a significant decrease in subsets of CD8+ T cells and mononuclear cells (P = .040 and.013, respectively), and, in a subset of cells, larger decreases in phosphoprotein expression were seen with greater increases in total 25-OHD levels. Inflammatory cytokines did not change significantly after Stoss dosing. Stoss dosing is therefore a safe and effective approach to maintain vitamin D sufficiency in the immediate post-HSCT period and may be associated with decreased HSCT-related complications. Randomized studies are warranted to further investigate the efficacy of Stoss-dosed vitamin D to improve bone health and reduce complications in pediatric patients receiving HSCT.

Stoss therapy is safe for treatment of vitamin D deficiency in pediatric patients undergoing HSCT

Vitamin D deficiency remains common among pediatric patients undergoing hematopoietic stem cell transplant (HSCT) despite both aggressive and standard of care strategies. This study examined the safety and efficacy of single high-dose oral vitamin D therapy (Stoss therapy) for treatment of vitamin D deficiency in HSCT recipients. Patients ages 1-21 years presenting for HSCT were randomized to receive either Stoss regimen plus weekly/daily supplementation or standard of care, per US Endocrine Society guidelines. Among the total 48 subjects, 22 (46%) were randomized to Stoss and 26 (54%) to control arms. Baseline 25-hydroxyvitamin D (25-OHD) levels were insufficient/deficient in total of 34 (71%) patients, without difference between treatment groups. The Stoss regimen was well tolerated and no toxicity was observed. At Day +30, mean 25-OHD levels were significantly higher (P = 0.04) with Stoss (42.3 ± 12 μg/l) compared to controls (35.6 ± 14.3 μg/l), and a higher proportion of Stoss patients had adequate vitamin D levels than controls (85% vs 65%). Stoss therapy is a safe and efficacious treatment option for vitamin D deficiency in children undergoing HSCT and may achieve sufficient levels more rapidly than standard of care. This trial was registered at www.clinicaltrials.gov as NCT03176849.

Cytomegalovirus Infection Downregulates Vitamin D Receptor in Patients Undergoing Hematopoietic Stem Cell Transplantation

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative option for patients with hematologic diseases but is associated with high mortality and morbidity. Cytomegalovirus (CMV) infection is common in HSCT patients and modulates vitamin D metabolism in vitro. We aimed at validating CMV-associated vitamin D metabolism in vivo in HSCT.

METHODS

Patients treated for significant CMV viremia after HSCT were evaluated for CMV load before, during, and after antiviral treatment. RNA was isolated from whole-blood samples to test for regulation of key components of the vitamin D receptor (VDR) pathway during different phases of CMV viremia.

RESULTS

CMV viremia developed a mean time of 102 (±34) d post-HSCT. Maximum levels of CMV-DNA reached a mean of 5668 (±7257) copies/mL. VDR expression was downregulated to a mean of 64.3% (±42.5%) relative to the VDR expression pre-CMV viremia (P = 0.035) and lagged in recovery following antiviral treatment. Toll-like receptor (TLR) 2 mRNA was upregulated to 225.4% during CMV viremia relative to the expression pre-CMV viremia (P = 0.012) but not TLR6/7/8 and the TLR-adaptor protein MyD88. Levels of 25-OH vitamin D were reduced in all viremic patients (48.0 ± 4.8 versus 25.1 ± 3.7 ng/mL) and were even lower after periods of CMV viremia compared with the control group (48.3 ± 3.5 versus 17.8 ± 1.8 ng/mL; P = 0.008).

CONCLUSIONS

CMV viremia is associated with significant dysregulation of vitamin D metabolism in HSCT patients.

Insights Into the Role of Vitamin D as a Biomarker in Stem Cell Transplantation

Vitamin D was discovered 100 years ago and since then multiple studies have consistently proved its effect on bone health and mineral metabolism. Further research has also explored its so-called "non-classical" biological effects, encompassing immune regulation and control of cell proliferation and differentiation. Vitamin D downregulates pro-inflammatory immune cells and subsequently their cytokine production, while enhancing the anti-inflammatory subsets, thus mediating inflammation and fostering a more tolerogenic environment. Its biological action is exerted through the vitamin D receptor, a nuclear receptor that mediates gene transcription and is expressed in most cells from the innate and adaptive immunity. Owing to its immune-modulatory properties, its role in cancer pathophysiology, hematology disorders and stem cell transplantation has also been investigated. Vitamin D deficiency causes immune imbalance and cytokine dysregulation, contributing to some autoimmune diseases. In the hematopoietic stem cell transplant setting this could lead to complications such as acute and chronic graft-versus-host disease, ultimately impacting transplant outcomes. Other factors have also been linked to this, including specific polymorphisms of the vitamin D receptor in both stem cell donors and recipients. Nevertheless, studies thus far have shown conflicting results and the use of vitamin D or its receptor as biomarkers has not been validated yet, therefore there are no evidence-based consensus guidelines to guide clinicians in their day-to-day practice. To gain more insight in this topic, we have reviewed the existent literature and gathered the current evidence. This is an overview of the role of serum vitamin D and its receptor as biomarkers for clinical outcomes in patients undergoing hematopoietic stem cell transplantation. Further prospective studies with larger cohorts are warranted to validate the viability of using serum vitamin D, and its receptor, as biomarkers in potential stem cell donors and patients, to identify those at risk of post-transplant complications and enable early therapeutic interventions.

To D or not to D: vitamin D in hematopoietic cell transplantation

Vitamin D plays an essential role in bone health, immune tolerance, and immune modulation. Autologous and allogeneic hematopoietic cell transplantation (HCT) recipients are at increased risk of vitamin D deficiency, which may increase risks of bone loss and fracture, graft-versus-host disease (GVHD), and relapse, and can delay hematologic and immune recovery following HCT. Growing evidence indicates that vitamin D may have a role as an immunomodulator, and supplementation during HCT may decrease the risk of GVHD, infection, relapse, and mortality. In this paper, we review the role of vitamin D and its association with HCT outcomes and discuss prevention and treatment of vitamin D deficiency after HCT in adult recipients. We review the role of monitoring of vitamin D levels pre- and post-HCT and its supplementation in appropriate patients. We also review the use of bone densitometry prior to HCT and in long-term follow-up and the treatment of osteoporosis in this high-risk population.

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Graft- versus -host disease

The Brazilian Consensus on Nutrition in Hematopoietic Stem Cell Transplantation: Graft- versus -host disease was approved by Sociedade Brasileira de Transplante de Medula Óssea , with the participation of 26 Brazilian hematopoietic stem cell transplantation centers. It describes the main nutritional protocols in cases of Graft- versus -host disease, the main complication of hematopoietic stem cell transplantation.

Oral calcitriol in hematopoietic recovery and survival after autologous stem cell transplantation: a randomized clinical trial

BACKGROUND

Calcitriol, the active metabolite of vitamin D, is an essential regulator in the hematopoiesis and immunity. However, knowledge revealing its influence on the immune and hematologic reconstitution after hematopoietic stem cell transplantation (HSCT) in clinical trials is very limited.

OBJECTIVES

The effects of calcitriol on short-term and long-term hematopoietic recovery, relapse-free survival (RFS) and overall survival (OS) in multiple myeloma, Hodgkin's and non-Hodgkin's lymphoma following autologous peripheral blood HSCT were assessed.

METHODS

Eighty patients (age: 18-68 years) in complete remission were allocated 1:1 to two groups by balanced block randomization. Calcitriol 0.25 μg or placebo capsule was administered three times daily from transplantation to day 30. Absolute neutrophil count (ANC), absolute lymphocyte count (ALC), and platelet count (PC) were determined daily from transplantation to day 30. White blood cell count (WBC), PC, and hemoglobin concentration (HC) of days 180 and 365 were extracted from clinic files. A thorough examination for oral mucositis (OM) was completed daily during hospital stay. Adverse drug reactions (ADRs) as well as two-year RFS and OS were evaluated.

RESULTS

Median time to ANC engraftment (≥0.5 × 103/μl: 10.0 vs. 11.0 days; P = 0.98) and PC engraftment (≥20.0 × 103/μl: both 14.0 days; P = 0.58) was similar between groups. However, the median time to ALC recovery was significantly shorter in the calcitriol group (≥0.5 × 103/μl: 13.0 vs. 20.0 days; P < 0.001). Moreover, ALC recovery rates on day 15 (≥0.5 × 103/μl: 82.1% vs. 42.5%; P < 0.001) and on day 30 (≥1.0 × 103/μl: 91.7% vs. 57.5%; P = 0.001) was significantly higher with calcitriol. WBC, PC, and HC on days 180 and 365 were not significantly different between groups. None of the OM indices were modulated by calcitriol. All the ADRs were non-serious and mild, possibly or unlikely related to the intervention. In a median of 29 months follow-up, RFS was significantly better in the calcitriol group (77.0%, SE = 7.0% vs. 59.0%, SE = 8.0%; P = 0.03), albeit the OS was not affected (87.0%, SE = 5.0% vs. 92.0%, SE = 4.0%; P = 0.72).

CONCLUSION

Calcitriol could improve ALC recovery and RFS as a safe option post-HSCT. Graphical abstract Oral calcitriol 0.25 µg three times daily from transplantation to day 30 improved lymphocytes recovery and two-year relapse-free survival as a safe option in 80 patients of autologous hematopoietic stem cell transplantation in comparison with placebo.

Regulation of the Immune Balance During Allogeneic Hematopoietic Stem Cell Transplantation by Vitamin D

One of the most promising therapeutic approaches for numerous hematological malignancies represents the allogeneic hematopoietic stem cell transplantation (allo-HSCT). One major complication is the development of the life-threatening graft-vs.-host disease (GvHD) which limits beneficial effects of graft-vs.-leukemia (GvL) responses during allo-HSCT. Strengthening GvL effects without induction of severe GvHD is essential to decrease the relapse rate after allo-HSCT. An interesting player in this context is vitamin D₃ since it has modulatory capacity in both preventing GvHD and boosting GvL responses. Current studies claim that vitamin D₃ induces an immunosuppressive environment by dendritic cell (DC)-dependent generation of regulatory T cells (Tregs). Since vitamin D₃ is known to support the antimicrobial defense by re-establishing the physical barrier as well as releasing defensins and antimicrobial peptides, it might also improve graft-vs.-infection (GvI) effects in patients. Beyond that, alloreactive T cells might be attenuated by vitamin D₃-mediated inhibition of proliferation and activation. Despite the inhibitory effects of vitamin D₃ on T cells, anti-tumor responses of GvL might be reinforced by vitamin D₃-triggered phagocytic activity and antibody-based immunotherapy. Therefore, vitamin D₃ treatment does not only lead to a shift from a pro-inflammatory toward a tolerogenic state but also promotes tumoricidal activity of immune cells. In this review we focus on vitamin D₃ and its immunomodulatory effects by enhancing anti-tumor activity while alleviating harmful allogeneic responses in order to restore the immune balance.

Impact of Vitamin D Supplementation on Influenza Vaccine Response and Immune Functions in Deficient Elderly Persons: A Randomized Placebo-Controlled Trial

Background: Immunosenescence contributes to reduced vaccine response in elderly persons, and is worsened by deficiencies in nutrients such as Vitamin (Vit-D). The immune system is a well-known target of Vit-D, which can both potentiate the innate immune response and inhibit the adaptive system, and so modulate vaccination response. Objective: This randomized placebo-controlled double-blind trial investigated whether Vit-D supplementation in deficient elderly persons could improve influenza seroprotection and immune response. Design: Deficient volunteers (Vit-D serum <30 ng/mL) were assigned (V1) to receive either 100,000 IU/15 days of cholecalciferol (D, n = 19), or a placebo (P, n = 19), over a 3 month period. Influenza vaccination was performed at the end of this period (V2), and the vaccine response was evaluated 28 days later (V3). At each visit, serum cathelicidin, immune response to vaccination, plasma cytokines, lymphocyte phenotyping, and phagocyte ROS production were assessed. Results: Levels of serum 25-(OH)D increased after supplementation (D group, V1 vs. V2: 20.7 ± 5.7 vs. 44.3 ± 8.6 ng/mL, p < 0.001). No difference was observed for serum cathelicidin levels, antibody titers, and ROS production in D vs. P groups at V3. Lower plasma levels of TNFα (p = 0.040) and IL-6 (p = 0.046), and higher ones for TFGβ (p = 0.0028) were observed at V3. The Th1/Th2 ratio was lower in the D group at V2 (D: 0.12 ± 0.05 vs. P: 0.18 ± 0.05, p = 0.039). Conclusions: Vit-D supplementation promotes a higher TGFβ plasma level in response to influenza vaccination without improving antibody production. This supplementation seems to direct the lymphocyte polarization toward a tolerogenic immune response. A deeper characterization of metabolic and molecular pathways of these observations will aid in the understanding of Vit-D's effects on cell-mediated immunity in aging. This clinical trial was registered at clinicaltrials.gov as NCT01893385.

The Role of Micronutrients in Graft-VS.-Host Disease: Immunomodulatory Effects of Vitamins A and D

Graft-vs.-host disease (GVHD) remains a major obstacle to the success of allogeneic hematopoietic stem cell transplantation (HSCT). GVHD occurs because donor T cells in the allograft recognize the genetically disparate host as foreign and attack the transplant recipient's tissues. While genetic incompatibility between donor and recipient is the primary determinant for the extent of alloimmune response, GVHD incidence and severity are also influenced by non-genetic factors. Recent advances in immunology establish that environmental factors, including dietary micronutrients, contribute significantly to modulating various immune responses and may influence the susceptibility to autoimmune and inflammatory diseases of experimental animals and humans. Emerging clinical and preclinical evidence indicates that certain micronutrients may participate in regulating GVHD risk after allogeneic HSCT. In this review, we summarize recent advances in our understanding with respect to the potential role of micronutrients in the pathogenesis of acute and chronic GVHD, focusing on vitamins A and D.

Vitamin D: is it important in haematopoietic stem cell transplantation? A review

Vitamin D has effects on several body systems, from well-established role in bone metabolism to emerging effects on the immune system. Increasing evidence supports an immunomodulatory effect including inhibition of the pro-inflammatory lymphocyte subsets while enhancing their anti-inflammatory counterpart, in favour of a more tolerogenic status. Vitamin D deficiency is increasingly recognised in association with autoimmune and inflammatory diseases, also with evidence from the field of asthma where vitamin D supplementation may overcome steroid resistance. In the HSCT setting, vitamin D deficiency has been variably associated with increased complications, including graft-versus-host disease (GvHD), with a potential impact on survival outcomes. In this review we provide an overview and critical appraisal of the current literature of the role of vitamin D (and its deficiency) in relation to immunity in both allogeneic and autologous HSCT settings. We conclude that the evidence base is mixed, but a greater understanding of the role of vitamin D in relation to immune reconstitution following HSCT is warranted. Given its potential benefits, its inexpensive cost and favourable side effect profile, consideration of vitamin D levels and its supplementation could be easily incorporated into prospective studies in GvHD, including clinical trials of novel therapeutics, supportive care and biomarkers.

Pretransplant Vitamin D Deficiency Is Associated With Higher Relapse Rates in Patients Allografted for Myeloid Malignancies

Purpose Vitamin D (VitD) deficiency is common in patients with hematologic malignancies undergoing allogeneic transplantation (alloSCT), but its prognostic relevance is unclear. Patients and Methods The impact of pretransplant VitD status on overall survival, relapse mortality, and nonrelapse mortality was investigated retrospectively in a cohort of 492 patients undergoing alloSCT at our center from 2002 to 2013. VitD deficiency was defined as a serum level of 25-hydroxyvitamin D3 < 20 ng/mL (equivalent to < 50 nM) before alloSCT and was assessed using accredited laboratory methods and a standard chemiluminescent immunoassay. Results were validated in an independent cohort of 398 patients diagnosed with myeloid malignancies. Results A total of 396 (80%) and 348 (87%) patients had VitD deficiency before alloSCT in the training and validation cohort, respectively. In the training cohort, VitD deficiency was significantly associated with inferior overall survival (hazard ratio [HR], 1.78; P = .007) in multivariable analysis. This was due to a higher risk of relapse (HR, 1.96; P = .006) rather than nonrelapse mortality. A significant association of pretransplant VitD deficiency with higher relapse rates was observed only in patients diagnosed with myeloid (HR, 2.55; P = .014) but not with lymphatic diseases (HR, 1.60; P = .147). A similar impact of pretransplant VitD deficiency on relapse risk in myeloid diseases was also observed in an independent patient cohort (HR, 2.60; P = .017). Validation of the effect of VitD deficiency on relapse in patients with myeloid malignancies was successful. Conclusion Pretransplant VitD deficiency was associated with a higher risk of relapse in patients allografted for myeloid malignancies. Prospective studies on VitD status and correction of VitD deficiency in the setting of alloSCT are highly warranted.

Increased incidence of chronic GvHD and CMV disease in patients with vitamin D deficiency before allogeneic stem cell transplantation

Vitamin D has emerged as a central player in the immune system, with its deficiency being implicated in the pathogenesis of several autoimmune diseases, including chronic GvHD. This is a retrospective cohort analysis of 166 patients, who underwent allogeneic hematopoietic stem cell transplantation (HSCT) at the Karolinska University Hospital, evaluating GvHD, graft failure, infectious complications and survival after HSCT in relation to pre-transplantation vitamin D levels. Most of the patients were deficient in vitamin D before HSCT (median 42 nmol/L). In multivariate analysis, vitamin D level before HSCT was identified as a significant independent risk factor for development of cGvHD. The increased incidence of cGvHD was not coupled to better disease-free survival; instead there was a trend towards lower overall survival in the vitamin D-deficient patients. In addition, we found a significant correlation between vitamin D deficiency and incidence of CMV disease, with no case of CMV disease occurring in patients with sufficient levels of vitamin D before HSCT. Our results support a role of vitamin D in immune tolerance following HSCT. These findings could be highly relevant for the care of HSCT patients, and prospective, randomized studies on the effect of vitamin D supplementation are therefore needed.

Vitamin d levels affect outcome in pediatric hematopoietic stem cell transplantation

The importance of vitamin D in immunologic processes has recently emerged, but whether it has any impact on the course of allogeneic hematopoietic stem cell transplantation (HSCT) has not been determined. Reports indicate that HSCT recipients, particularly children, often suffer from vitamin D deficiency. This study investigated the role of vitamin D in 123 children undergoing HSCT from 2004 to 2011. Vitamin D (ie, serum calcidiol) was analyzed in collected cryostored samples. Patients were grouped according to pre-HSCT calcidiol level: insufficient (<50 nm/L, n = 38) and sufficient (≥50 nm/L, n = 85). Older children who underwent transplants from January through June and children of Middle Eastern or African origin were more commonly found in the insufficient group. Acute grades II to IV graft-versus-host disease occurred more frequently in the vitamin D sufficient group (47% versus 30%, P = .05), whereas no difference was demonstrated for chronic graft-versus-host disease. The neutrophil granulocytes rose significantly faster in the vitamin D sufficient group. No difference in lymphocyte counts, immunoglobulin levels, or infectious disease burden during the first year post-HSCT were observed. Among children with malignancies, overall survival was significantly better in the sufficient group (87% versus 50%, P = .01). In addition, rejection (0% versus 11%, P = .06) and relapse (4% versus 33%, P = .03) rates were lower in patients with sufficient vitamin D levels. To conclude, vitamin D may have an important impact on the outcome of pediatric HSCT, particularly in patients with malignant disease. Further studies investigating whether vitamin D acts as an immunomodulator or is merely a surrogate marker of patient health or nutritional status are warranted.

Vitamin D deficiency in children and adolescents submitted to hematopoietic stem cell transplantation

BACKGROUND

Sub-optimal levels of vitamin D have been found to be highly prevalent in all age groups, with epidemiologic studies demonstrating a link between vitamin D deficiency and disease susceptibility, such as infection and cancer, and mortality rates. In adult transplant patients, it has been suggested that the immunomodulatory properties of vitamin D may have an important role in the prevention and treatment of graft-versus-host disease.

OBJECTIVE

The objective of this study was to assess serum 25-hydroxyvitamin D levels of children and adolescents submitted to allogeneic hematopoietic stem cell transplantation.

METHODS

Serum 25-hydroxyvitamin D levels of 66 patients, aged 4-20 years, were assessed at three stages: before hospitalization for hematopoietic stem cell transplantation and at 30 and 180 days after hematopoietic stem cell transplantation. The control group consisted of 25 healthy children.

RESULTS

At the pre-hematopoietic stem cell transplantation stage, patients had lower levels of 25-hydroxyvitamin D compared to controls (25.7 ± 12.3 ng/mL vs. 31.9 ± 9.9 ng/mL; p-value = 0.01), and a higher prevalence of 25-hydroxyvitamin D deficiency (32% vs. 8%; p-value = 0.01). Prevalence increased significantly after hematopoietic stem cell transplantation (p-value = 0.01) with half of the patients having vitamin D deficiency at 180 days after transplantation. At this stage, mean serum 25-hydroxyvitamin D levels were 20.9 ± 10.9 ng/mL, a significant decline in relation to baseline (p-value = 0.01). No correlation was found between 25-hydroxyvitamin D levels and vitamin D intake, graft-versus-host disease, corticoid use or survival rates.

CONCLUSION

Low levels of 25-hydroxyvitamin D were detected even before hematopoietic stem cell transplantation and were significantly lower at 180 days after hematopoietic stem cell transplantation, thus recommending vitamin D supplementation for children and adolescents submitted to hematopoietic stem cell transplantation.

Influence of vitamin D status and vitamin D3 supplementation on genome wide expression of white blood cells: a randomized double-blind clinical trial

Background

Although there have been numerous observations of vitamin D deficiency and its links to chronic diseases, no studies have reported on how vitamin D status and vitamin D₃ supplementation affects broad gene expression in humans. The objective of this study was to determine the effect of vitamin D status and subsequent vitamin D supplementation on broad gene expression in healthy adults. (Trial registration: ClinicalTrials.gov NCT01696409).

Methods and Findings

A randomized, double-blind, single center pilot trial was conducted for comparing vitamin D supplementation with either 400 IUs (n = 3) or 2000 IUs (n = 5) vitamin D₃ daily for 2 months on broad gene expression in the white blood cells collected from 8 healthy adults in the winter. Microarrays of the 16 buffy coats from eight subjects passed the quality control filters and normalized with the RMA method. Vitamin D₃ supplementation that improved serum 25-hydroxyvitamin D concentrations was associated with at least a 1.5 fold alteration in the expression of 291 genes. There was a significant difference in the expression of 66 genes between subjects at baseline with vitamin D deficiency (25(OH)D<20 ng/ml) and subjects with a 25(OH)D>20 ng/ml. After vitamin D₃ supplementation gene expression of these 66 genes was similar for both groups. Seventeen vitamin D-regulated genes with new candidate vitamin D response elements including TRIM27, CD83, COPB2, YRNA and CETN3 which have been shown to be important for transcriptional regulation, immune function, response to stress and DNA repair were identified.

Conclusion/Significance

Our data suggest that any improvement in vitamin D status will significantly affect expression of genes that have a wide variety of biologic functions of more than 160 pathways linked to cancer, autoimmune disorders and cardiovascular disease with have been associated with vitamin D deficiency. This study reveals for the first time molecular finger prints that help explain the nonskeletal health benefits of vitamin D.

Trial Registration

ClinicalTrials.gov NCT01696409

Advances in predicting acute GVHD

Acute graft-versus-host disease (GVHD) is a leading cause of non-relapse mortality following allogeneic haematopoietic cell transplantation. Attempts to improve treatment response in clinically-established GVHD have not improved overall survival, often due to the increased risk of infectious complications. Alternative approaches to decrease GVHD-related morbidity and mortality have focused on the ability to predict GVHD prior to clinical manifestation in an effort to provide an opportunity to abort GVHD development, and to gain new insights into GVHD pathophysiology. This review outlines the research efforts to date that have identified clinical and laboratory-based factors that are predictive of acute GVHD and describes future directions in developing algorithms that will improve the ability to predict the development of clinically relevant GVHD.

Vitamin D receptor upregulation in alloreactive human T cells

Vitamin D deficiency is adversely associated with diseases characterized by inflammation. The combination of the high incidence of vitamin D deficiency in patients undergoing allogeneic stem cell transplants (SCT) and the potential role of vitamin D deficiency in influencing graft-versus-host disease led us to further characterize the expression of VDR on alloreactive T cells. We hypothesized that vitamin D receptor expression may directly regulate alloreactive T cell responses. To overcome existing limitations in measuring VDR in bulk cellular populations, we developed a flow cytometric assay to measure cytoplasmic VDR in human T cells. Upon stimulation, VDR was expressed extremely early and exhibited sustained upregulation with chronic stimulation. VDR expression was also coupled to cytokine production, proliferation, and ERK1/2 phosphorylation. In addition, VDR exhibited a maturation stage-specific pattern of expression, with greatest expression on cells known to mediate GVHD, naïve and early memory T cells. Alloreactive T cells upregulated VDR, whereas the nonreactive T cells did not. Finally, repletion of vitamin D in vitro was sufficient to significantly reduce alloreactive T cell responses. These data suggest that vitamin D effects on T cells may be important in reducing graft versus host disease (GVHD) in the allogeneic stem cell transplant setting.

Effects of 1,25(OH)2 vitamin D3 on cytokine production by endometrial cells of women with recurrent spontaneous abortion

OBJECTIVE

To investigate immunomodulatory effect of 1,25(OH)2 vitamin D3 (1,25(OH)2D3) on cytokine production by endometrial cells of women with unexplained recurrent spontaneous abortion (URSA).

DESIGN

In vitro study.

SETTING

Academic research center.

PATIENT(S)

Patients with URSA and healthy controls.

INTERVENTION(S)

Treatment with 1,25(OH)2D3.

MAIN OUTCOME MEASURE(S)

Production of interferon γ (IFN-γ), interleukin-10 (IL-10), transforming growth factor β (TGF-β), IL-17, IL-6, and IL-8 by whole endometrial cells (WECs) and endometrial stromal cells in the presence and absence of 1,25(OH)2D3 and 1α-hydroxylase activity of these cell populations were measured in patients with URSA and healthy controls.

RESULT(S)

1,25(OH)2D3 interfered with production of cytokines by WECs of the control and URSA groups, except IL-8 which was increased in URSA group. In endometrial stromal cells, 1,25(OH)2D3 down-regulated cytokine production as well with stimulatory effect on the production of TGF-β in patients with URSA. Cytokine profile of WECs from patients with URSA skewed toward TH2 phenotype after treatment with 1,25(OH)2D3. Endometrial cells of both groups had comparable capacity to produce 1,25(OH)2D3.

CONCLUSION(S)

Considering the complex network of immunoregulation at the fetomaternal interface, potential beneficial effects of vitamin D3 in patients with URSA need to be investigated in clinical practice. Comparable levels of 1,25(OH)2D3 production and similar trend of cytokine expression by WECs of URSA and control groups after vitamin D3 treatment reflect the same local metabolic machinery of this hormone.

Vitamin D status among long-term survivors of hematopoietic cell transplantation

Little is known about serum vitamin D levels following hematopoietic cell transplantation (HCT). Patients are instructed to avoid sun exposure due to an increased risk of skin cancers. Altered gastrointestinal absorptive capacity as a result of GVHD, bile acid or pancreatic enzyme insufficiency, or bacterial overgrowth may lead to difficulty absorbing the fat soluble vitamin D. This study was undertaken to determine the prevalence of serum 25-hydroxyvitamin D (25(OH)D) deficiency, and factors associated with 25(OH)D deficiency, among children and adults who were at least one year following HCT. A total of 95 participants (54 males, 41 females) completed a questionnaire on usual diet and lifestyle, and provided a blood sample for 25(OH)D determinations between November 2008 and July 2009. The majority of participants had serum 25(OH)D levels ≥75 nmol/L (n=62, 65%), 23 had insufficient levels (50–75 nmol/L), and 10 participants were deficient (<50 nmol/L). The majority of participants reported regular vitamin D supplement use (n=58, 61%). Prednisone use was significantly inversely associated with serum 25(OH)D concentrations. Total vitamin D intake was the strongest single predictor of 25(OH)D concentrations. These findings suggest that 400–600 IU vitamin D/day appear to be required to achieve optimal serum 25(OH)D concentrations following HCT.

Vitamin D in solid organ transplantation with special emphasis on kidney transplantation

Within the past decades, vitamin D was identified as having additional physiological functions far beyond calcium homeostasis and bone metabolism. Stimulated by the discovery of the vitamin D receptor in a broad range of tissues as well as the expression of 1α-hydroxylase, the enzyme responsible for the activation of vitamin D, it became evident that the actions of vitamin D are not restricted to cells involved in mineral and bone metabolism. In fact, it affects proliferation, differentiation, and function of a large number of different cell types including cells of the immune system. Vitamin D receptor agonists were found to exert immunosuppressive effects on the adaptive immune system, thus being able to mediate immunologic tolerance. However, they promote the innate immune system and thereby improve the ability of the host to combat invading pathogens. This review summarizes our current understanding of vitamin D as an immunomodulatory agent with special emphasis on its clinical implications in the transplant setting.

1α,25-dihydroxyvitamin D3 (vitamin D3) catalyzes suppressive activity on human natural regulatory T cells, uniquely modulates cell cycle progression, and augments FOXP3

Human natural regulatory T cells (nTregs) show great promise for therapeutically modulating immune-mediated disease, but remain poorly understood. One explanation under intense scrutiny is how to induce suppressive function in non-nTregs and increase the size of the regulatory population. A second possibility would be to make existing nTregs more effective, like a catalyst raises the specific activity of an enzyme. The latter has been difficult to investigate due to the lack of a robust short-term suppression assay. Using a microassay described herein we demonstrate that nTregs in distinct phases of cell cycle progression exhibit graded degrees of potency. Moreover, we show that physiological concentrations of 1α,25-dihydroxyvitamin D3 (vitamin D3) boosts nTregs function. The enhanced suppressive capacity is likely due to vitamin D3's ability to uniquely modulate cell cycle progression and elevate FOXP3 expression. These data suggest a role for vitamin D3 as a mechanism for catalyzing potency of nTregs.