Incidence, severity, and temporal development of oral complications in pediatric allogeneic hematopoietic stem cell transplant patients - a multicenter study.

PURPOSE: Oral mucositis is a common complication for patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT) and causes pain and difficulties in functions like eating and swallowing, resulting in lower quality of life and greater need of treatment with opioids and parenteral nutrition. This prospective multicenter study focused on pediatric recipients of HSCT in the neutropenic phase concerning oral complications, timing, severity, and patient experience. METHODS: The cohort comprised 68 patients, median age 11.1 years (IQR 6.3) receiving allogeneic HSCT at three clinical sites. Medical records were retrieved for therapy regimens, concomitant medications, oral and dental history, and subjective oral complaints. Calibrated dentists conducted an oral and dental investigation before HSCT. After HSCT graft infusion, study personnel made bedside assessments and patients filled out a questionnaire once or twice a week until neutrophil engraftment. RESULTS: We followed 63 patients through the neutropenic phase until engraftment. 50% developed oral mucositis of grades 2-4. Peak severity occurred at 8-11 days after stem cell infusion. Altogether, 87% had subjective oral complaints. The temporal distribution of adverse events is similar to the development of oral mucositis. The most bothersome symptoms were blisters and oral ulcerations, including mucositis; 40% reported severe pain and major impact on activities of daily living despite continuous use of opioids. CONCLUSION: This study highlights the burden of oral complications and their negative effect on the health and quality of life of HSCT recipients.

Oral mucositis after tacrolimus/sirolimus or cyclosporine/methotrexate as graft-versus-host disease prophylaxis.

OBJECTIVES: To determine whether treatment with tacrolimus plus sirolimus (Tac/Sir) as a prophylaxis for graft-versus-host disease worsens severe oral mucositis and delays healing compared to cyclosporine plus methotrexate (CsA/Mtx) following haematopoietic stem cell transplantation. SUBJECTS AND METHODS: The study comprised 141 patients: 73 randomized to receive Tac/Sir and 68 to receive CsA/Mtx. The oral mucositis assessment scale and toxicity grading according to WHO were used to assess the severity, peak and duration of oral mucositis from the day -3 to day 24 post-transplant. RESULTS: Eighty-seven patients developed oral mucositis in the first 24 days post-transplant. No significant difference in oral mucositis severity between the Tac/Sir and CsA/Mtx groups was observed. The peak oral mucositis score occurred on day 10 in both groups. Although oral mucositis scores had returned to baseline in the CsA/Mtx group on day 24 post-transplant, no significant difference compared with the Tac/Sir group was found. CONCLUSIONS: The introduction of tacrolimus/sirolimus as a graft-versus-host disease prophylaxis in haematopoietic stem cell transplantation increased neither the incidence nor severity of oral mucositis compared with cyclosporine/methotrexate. Furthermore, oral mucositis healing was not prolonged and followed the same time pattern as cyclosporine/methotrexate.

Effect of Graft-versus-Host Disease Prophylaxis Regimens on T and B Cell Reconstitution after Allogeneic Hematopoietic Stem Cell Transplantation.

Lymphocyte reconstitution is pivotal for successful long-term outcome after allogeneic hematopoietic stem cell transplantation (HSCT), and conditioning regimen and post-transplantation immunosuppression are risk factors for prolonged immunodeficiency. Nevertheless, the effects of different immunosuppressive protocols on lymphocyte output and replicative capacity have not been investigated. Here we assessed T cell receptor excision circles (TREC), kappa-deleting recombination excision circles (KREC), and T cell telomere length (TL) as proxy markers for immune reconstitution in patients in a prospective randomized trial comparing graft-versus-host disease (GVHD) prophylaxis after transplantation (cyclosporine/methotrexate versus tacrolimus/sirolimus; n = 200). Results showed that medians of TREC, KREC, and TL were not significantly different between the prophylaxis groups at any assessment time point during follow-up (24 months), but the kinetics of TREC, KREC, and TL were significantly influenced by other transplantation-related factors. Older recipient age, the use of antithymocyte globulin before graft infusion, and use of peripheral blood stem cell grafts were associated with lower TREC levels, whereas acute GVHD transiently affected KREC levels. Patients with lymphocyte excision circle levels above the median at ≤6 months post-transplantation had reduced transplantation-related mortality and superior 5-year overall survival (P < .05). We noticed significant T cell telomere shortening in the patient population as a whole during follow-up. Our results suggest that lymphocyte reconstitution after transplantation is not altered by different immunosuppressive protocols. This study has been registered at ClinicalTrials.gov (identifier: NCT00993343).

Impact of Pretransplantation Indices in Hematopoietic Stem Cell Transplantation: Knowledge of Center-Specific Outcome Data Is Pivotal before Making Index-Based Decisions.

Outcome after allogeneic hematopoietic stem cell transplantation is influenced by patient comorbidity, disease type, and status before treatment. We performed a retrospective study involving 521 consecutive adult hematopoietic stem cell transplantation patients who underwent transplantation for hematological malignancy at our center from 2000 to 2012 to compare the predictive value of the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) and the disease risk index (DRI) for overall survival and transplantation-related mortality. Patients in the highest HCT-CI risk group (HCT-CI score ≥3) had a lower 5-year overall survival rate (50%) than the low-risk group (63%; P < .01). Subset analysis of donor origin showed greater 5-year overall survival in siblings than in matched unrelated donors, regardless of HCT-CI score (eg, 67% 5-year overall survival in siblings despite an HCT-CI score of >6 [n = 9]). Five-year overall survival in the highest DRI risk group was significantly poorer (44%) than in the low-risk group (63%; P < .01). Both indices failed to predict differences in transplantation-related mortality (HCT-CI, P = .54; DRI, P = .17). We conclude that HCT-CI and DRI were predictive of overall survival in our patient population. Even so, our data show that different patient groups may have different outcomes despite sharing the same index risk group and that indices should, therefore, be evaluated according to local data before clinical implementation at the single-center level.

Risk Factors for Invasive Mold Infections and Implications for Choice of Prophylaxis after Allogeneic Stem Cell Transplantation.

Invasive mold infections (IMIs) are major complications after allogeneic hematopoietic stem cell transplantation (HSCT) with high mortality. We retrospectively investigated incidence and risk factors for IMI after 797 HSCTs in a center with high autopsy frequency, trying to identify patient groups that would potentially benefit from mold-active prophylaxis. The cumulative 1-year incidence of IMI was 2.1% in patients aged 21 to 40, 7.1% in patients aged 41 to 60, and 16.4% in patients > 60 years of age (P < .01 for patients aged 21 to 40 versus 41 to 60, P < .001 for patients aged 21 to 40 versus patients > 60). Risk factors for a new IMI in multivariate analysis were older age, grades II to IV acute graft-versus-host disease (GVHD) (risk hazard, 4.1; 95% CI, 1.9 to 8.8; P < .001), treatment with mesenchymal stromal cells (risk hazard, 4.0; 95% CI, 2.1 to 7.8; P < .001), transplantation with female donor to male recipient (risk hazard, 2.2; 95% CI, 1.1 to 4.3; P = .02), and hematopoietic stem cell transplantation-specific comorbidity index over 5 (risk hazard, 2.8; 95% CI, 1.1 to 6.8; P = .03). In patients with grade II acute GVHD, no IMI was seen after onset of acute GVHD in 109 HSCTs performed in patients < 40 years of age, as compared with 14 IMIs in 97 HSCTs (14%) performed in patients > 40 years of age (P < .001). To conclude, older age is an important risk factor for developing IMIs, and patients < 40 years of age with grade II acute GVHD do not appear to need mold-active prophylaxis unless receiving prolonged treatment with corticosteroids.

A prospective randomized trial comparing cyclosporine/methotrexate and tacrolimus/sirolimus as graft-versus-host disease prophylaxis after allogeneic hematopoietic stem cell transplantation.

Improvement of graft-versus-host disease prophylaxis remains an important goal in allogeneic hematopoietic stem cell transplantation. Based on reports of possibly preferential properties of sirolimus, we compared the standard regimen of cyclosporine and methotrexate (n=106) with a combination of tacrolimus and sirolimus (n=103) as graft-versus-host disease prophylaxis after allogeneic hematopoietic stem cell transplantation in a prospective, open, randomized trial. The hypothesis was that the tacrolimus/sirolimus regimen would lead to less acute graft-versus-host disease and reduced transplant-related mortality. There was no significant difference in the cumulative incidence of acute graft-versus-host disease of grades II-IV (41% vs. 51%; P=0.19) or grades III-IV (13% vs. 7%; P=0.09) between the groups. Time to neutrophil engraftment (18 days vs. 17 days; P=0.24) was similar, but time to platelet engraftment was longer in cyclosporine/methotrexate patients (14 vs. 12 days; P<0.01). No significant differences in incidence of oropharyngeal mucositis, time to full donor chimerism, or number of cytomegalovirus infections were seen between the two treatment arms, and transplant-related toxicities were equally distributed. Triglyceride (P=0.005) and cholesterol (P=0.009) levels were higher in tacrolimus/sirolimus patients. Transplant-related mortality (18% vs. 12%; P=0.40) and 5-year overall survival (72% vs. 71%; P=0.71) were similar. Five-year relapse-free survival in patients with malignant diagnoses was 65% in the cyclosporine/methotrexate group and 63% in the tacrolimus/sirolimus group (P=0.73). We conclude that tacrolimus/sirolimus remains a valid and safe alternative to cyclosporine/methotrexate as graft-versus-host disease prophylaxis after allogeneic hematopoietic stem cell transplantation, with comparable transplant-related outcomes. The trial was registered at clinicaltrials.gov identifier: 00993343.

Effect of Total Nucleated and CD34(+) Cell Dose on Outcome after Allogeneic Hematopoietic Stem Cell Transplantation.

During more recent years only few studies have analyzed the effect of total nucleated cell (TNC) and CD34(+) cell dose in allogeneic hematopoietic stem cell transplantation (HSCT). A single-center analysis included 544 patients, 227 with a sibling donor and 317 with an unrelated donor. Most patients (n = 292) were treated with myeloablative conditioning, whereas the remaining patients (n = 252) received reduced-intensity conditioning. Bone marrow (BM) (n = 121) and peripheral blood stem cell (PBSC) grafts (n = 423) were analyzed separately. Median TNC and CD34(+) cell dose was 3.2 × 10(8)/kg versus 11.6 × 10(8)/kg in BM and 3.9 × 10(6)/kg versus 8.1 × 10(6)/kg in PBSC. In the BM group we found a higher TNC and CD34(+) cell dose was associated with a faster neutrophil engraftment (P < .001 and P = .02). In the PBSC group we found patients given a very high (≥11 × 10(6)/kg) CD34(+) cell dose had decreased rates of survival (P = .001) and increased relapse (P = .02). A high CD34(+) cell dose correlated with faster platelet engraftment (P < .01). In HSCT using PBSCs, the CD34(+) cell doses should be kept below 11 × 10(6)/kg but over 2.5 × 10(6)/kg.

Low CD34 dose is associated with poor survival after reduced-intensity conditioning allogeneic transplantation for acute myeloid leukemia and myelodysplastic syndrome.

Reduced-intensity conditioning/nonmyeloablative conditioning regimens are increasingly used in allogeneic hematopoietic cell transplantation (HCT). Reports have shown CD34(+) dose to be important for transplantation outcome using myeloablative conditioning. The role of CD34(+) dose of peripheral blood progenitor cells (PBPC) has not been previously analyzed in a large population undergoing reduced-intensity conditioning/nonmyeloablative HCT. We studied 1054 patients, ages 45 to 75 years, with acute myeloid leukemia or myelodysplastic syndrome who underwent transplantation between 2002 and 2011. Results of multivariate analysis showed that PBPC from HLA-matched siblings containing <4 × 10(6) CD34(+)/kg was associated with higher nonrelapse mortality (hazard ratio [HR], 2.03; P = .001), overall mortality (HR, 1.48; P = .008), and lower neutrophil (odds ratio [OR], .76; P = .03) and platelet (OR, .76; P = .03) recovery. PBPC from unrelated donors with CD34(+) dose < 6 × 10(6) CD34(+)/kg was also associated with higher nonrelapse (HR, 1.38; P = .02) and overall mortality (HR, 1.20; P = .05). In contrast to reports after myeloablative HCT, CD34(+) dose did not affect relapse or graft-versus-host disease with either donor type. An upper cell dose limit was not associated with adverse outcomes. These data suggest that PBPC CD34(+) doses >4 × 10(6) CD34(+)/kg and >6 × 10(6) CD34(+)/kg are optimal for HLA-matched sibling and unrelated donor HCT, respectively.

Home care during neutropenia after allogeneic hematopoietic stem cell transplantation in children and adolescents is safe and may be more advantageous than isolation in hospital.

After ASCT, children are isolated in hospital to prevent neutropenic infections. Patients living within two-h drive from the hospital were given the option of treatment at home after ASCT. Daily visits by an experienced nurse and phone calls from a physician from the unit were included in the protocol. We compared 29 children and adolescents treated at home with 58 matched hospital controls. The children spent a median time of 13 days at home (range 2-24 days) and 6 (0-35) days in hospital. The cumulative incidence of acute GVHD grades II-IV was 21% in the home-care children and 39% in the controls (p = 0.1). Chronic GVHD and probability of relapse were similar in the two groups. TRM at five yr was 11% in the home-care patients and 18% in the controls. Overall survival at three yr was 77% and 62%, respectively (p = 0.33). None of the patients died at home. Median costs were 38,748 euros in the home-care patients and 49,282 euros in those treated in the hospital (p = 0.2). We conclude that it is safe for children and adolescents to be treated at home during the pancytopenic phase after ASCT.

Effect of mTOR Inhibition with Sirolimus on Natural Killer Cell Reconstitution in Allogeneic Stem Cell Transplantation.

Sirolimus is an inhibitor of the mammalian target of rapamycin (mTOR) and is emerging as a promising component of graft-versus-host disease (GVHD) prophylaxis regimens in the context of allogeneic hematopoietic stem cell transplantation (HSCT). Multiple studies have explored the clinical benefits of adding sirolimus to GVHD prophylaxis; however, detailed immunologic studies have not yet been carried out in this context. Mechanistically, mTOR is at the center of metabolic regulation in T cells and natural killer (NK) cells and is critical for their differentiation to mature effector cells. Therefore, close evaluation of the inhibition of mTOR in the context of immune reconstitution post-HSCT is warranted. In this work, we studied the effect of sirolimus on immune reconstitution using a biobank of longitudinal samples from patients receiving either tacrolimus/sirolimus (TAC/SIR) or cyclosporin A/methotrexate (CSA/MTX) as conventional GVHD prophylaxis. Healthy donor controls, donor graft material, and samples from 28 patients (14 with TAC/SIR, 14 with CSA/MTX) at 3 to 4 weeks and 34 to 39 weeks post- HSCT were collected. Multicolor flow cytometry was used to perform broad immune cell mapping, with a focus on NK cells. NK cell proliferation was evaluated over a 6-day in vitro homeostatic proliferation protocol. Furthermore, in vitro NK cell responses to cytokine stimulation or tumor cells were evaluated. Systems-level assessment of the immune repertoire revealed a deep and prolonged suppression (weeks 34 to 39 post-HSCT) of the naïve CD4 T cell compartment with relative sparing of regulatory T cells and enrichment of CD69+Ki-67+HLA-DR+ CD8 T cells, independent of the type of GVHD prophylaxis. Early after transplantation (weeks 3 to 4), while patients were still on TAC/SIR or CSA/MTX, we found a relative increase in less-differentiated CD56bright NK cells and NKG2A+CD57-KIR- CD56dim NK cells and a distinct loss of CD16 and DNAM-1 expression. Both regimens led to suppressed proliferative responses ex vivo and functional impairment with preferential loss of cytokine responsiveness and IFN-γ production. Patients who received TAC/SIR as GVHD prophylaxis showed delayed NK cell reconstitution with lower overall NK cell counts and fewer CD56bright and NKG2A+ CD56dim NK cells. Treatment with sirolimus-containing regimens generated similar immune cell profiles as conventional prophylaxis; however, the NK cell compartment seemed to be composed of slightly more mature NK cells. These effects were also present after the completion of GVHD prophylaxis, suggesting that mTOR inhibition with sirolimus leaves a lasting imprint on homeostatic proliferation and NK cell reconstitution following HSCT.

T cell receptor excision circles are potential predictors of survival in adult allogeneic hematopoietic stem cell transplantation recipients with acute myeloid leukemia.

Background: Lymphocyte neogenesis from primary lymphoid organs is essential for a successful reconstitution of immunity after allogeneic hematopoietic stem cell transplantation (HSCT). This single-center retrospective study aimed to evaluate T cell receptor excision circles (TREC) and kappa-deleting recombination excision circles (KREC) as surrogate markers for T and B cell recovery, as predictors for transplantation-related outcomes in adult acute myeloid leukemia (AML) patients. Methods: Ninety adult patients diagnosed with AML and treated with HSCT between 2010 and 2015 were included in the study. TREC and KREC levels were measured by quantitative PCR at 1, 3, 6, and 12 months after transplantation. Results: Overall, excision circle levels increased between 3 and 6 months post-HSCT for TREC (p = 0.005) and 1 and 3 months for KREC (p = 0.0007). In a landmark survival analysis at 12 months post-HSCT, TREC levels were associated with superior overall survival (HR: 0.52, 95% CI: 0.34 - 0.81, p = 0.004). The incidence of viral infections within the first 100 days after transplantation was associated with lower TREC levels at 6 months (p = 0.0002). CMV reactivation was likewise associated with lower TREC levels at 6 months (p = 0.02) post-HSCT. KREC levels were not associated with clinical outcomes in statistical analyzes. Conclusions: Results from the present study indicate that TREC measurement could be considered as part of the post-HSCT monitoring to identify AML patients with inferior survival after transplantation. Further prospective studies are warranted to validate these findings.

Cytokine levels following allogeneic hematopoietic cell transplantation: a match-pair analysis of home care versus hospital care.

Following allogeneic hematopoietic cell transplantation (HCT), patients living near the hospital were treated at home instead of in isolation in the hospital. We analyzed cytokines using Luminex assays for the first 3 weeks after HCT and compared patients treated at home (n = 42) with matched patients isolated in the hospital (n = 37). In the multivariate analysis, patients treated at home had decreased GM-CSF, IFN-γ (p < 0.01), IL-13, IL-5 (p < 0.05), and IL-2 (p < 0.07). Bloodstream infections, anti-thymocyte globulin, G-CSF treatment, immunosuppression, reduced-intensity conditioning (RIC), related vs. unrelated donors, and graft source affected various cytokine levels. When patients with RIC were analyzed separately, home care patients had reduced G-CSF (p = 0.04) and increased vascular endothelial growth factor (VEGF, p = 0.001) at 3 weeks compared with hospital care patients. Patients with low GM-CSF (p < 0.036) and low IFNγ (p = 0.07) had improved survival. Acute GVHD grades III-IV was seen in 7% and 16% of home care and hospital care patients, respectively. One-year transplantation-related mortality was 7% and 16% and survival at 5 years was 69% and 57% in the two groups, respectively. To conclude, patients treated in the hospital showed varying increased levels of GM-CSF, IFN-γ, IL-13, G-CSF, IL-5, and IL-2 and decreased VEGF, which may contribute to acute GVHD.

Reduced Risk of Sinusoidal Obstruction Syndrome of the Liver after Busulfan-Cyclophosphamide Conditioning Prior to Allogeneic Hematopoietic Stem Cell Transplantation.

The aim of this study is to evaluate the incidence of sinusoidal obstruction syndrome (SOS) of the liver and the clinical outcome after hematopoietic stem cell transplantation (HSCT) based on several modifications in our protocols. We retrospectively investigated 372 patients undergoing myeloablative conditioning with oral busulfan (Bu) and cyclophosphamide before allogeneic HSCT during 1990-2015. Patients' supportive care was changed in order to reduce the regimen-related toxicities. Norethisterone use was terminated in 1998, therapeutic drug monitoring of Bu was initiated in 2000, and the use of liver supportive drugs, such as ursodeoxycholic acid and N-acetyl-L-cysteine, were started in 2002 and 2009, respectively. In total, 26 patients (7.0%) developed SOS at a median of 19 days after transplantation. Of these 26 patients, 20 died at a median of 119 days after HSCT and 102 days after the diagnosis of SOS. The incidence of SOS decreased over time in accordance with the improvements in supportive care. The highest incidence of SOS was during 1995-1999 (16.2%) compared with 2.3% during 2010-2015. Overall survival for patients with SOS was 62%, 46%, and 27% at 100 days, 1 year, and 5 years after HSCT, respectively, compared with 92%, 77%, and 66% for those who did not develop SOS (P < 0.001). In conclusion, the incidence of SOS and related deaths were significantly decreased over the last years. Our institution pursues massive preventative and personalized measures for SOS. This strategy may also be applicable in other conditioning protocols in order to reduce the incidence of SOS and, hence, improve the clinical outcome.

Individualization of Hematopoietic Stem Cell Transplantation Using Alpha/Beta T-Cell Depletion.

Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with several potentially lethal complications. Higher levels of CD3+ T-cells in the graft have been associated with increased risk of graft-versus-host disease (GVHD), but also beneficial graft-versus-leukemia effect and reduced infections. To tackle post-transplant complications, donor lymphocyte infusions have been used but with an increased risk of GVHD. To reduce this risk, we performed depletion of αß T-cells and treated 12 patients post-HSCT suffering from infections and/or poor immune reconstitution. The αß T-cell depleted cell products were characterized by flow cytometry. The median log depletion of αß T-cells was -4.3 and the median yield of γδ T-cells was 73.5%. The median CD34+ cell dose was 4.4 × 106/kg. All 12 patients were alive 3 months after infusion and after 1 year, two patients had died. No infusion-related side effects were reported and no severe acute GVHD (grade III-IV) developed in any patient post-infusion. Overall, 3 months after infusion 11 out of 12 patients had increased levels of platelets and/or granulocytes. In conclusion, we describe the use of αß T-cell depleted products as stem cell boosters with encouraging results.

Toxicological effects of fludarabine and treosulfan conditioning before allogeneic stem-cell transplantation.

We studied early potential treosulfan-related toxicity in 118 patients treated with treosulfan-based conditioning before allogeneic hematopoietic stem-cell transplantation. Most patients (n = 93) had a hematological malignancy. In 80 cases, a HLA-A, -B and -DR matched unrelated donor was used, while 33 patients had a HLA-identical sibling donor, and five received an HLA-A, -B or -DR allele mismatched, unrelated donor. Levels of AST, ALT, and bilirubin were significantly increased 1 week after HSCT compared to before HSCT. However, only a few patients had transaminase levels >2 to 3 × the upper normal level. All patients became neutropenic; 61% were already so at the time of graft infusion. Nearly all patients engrafted, except for three who died very early. Non-relapse mortality was 7.5% at 100 days and 11.9% at 1 year after HSCT. Veno-occlusive disease of the liver occurred in one patient and hemorrhagic cystitis in two patients. This study shows that early regimen-related toxicity after HSCT was low despite similar marrow toxicities compared to myeloablative regimens.

Combining Flow and Mass Cytometry in the Search for Biomarkers in Chronic Graft-versus-Host Disease.

Chronic graft-versus-host disease (cGVHD) is a debilitating complication arising in around half of all patients treated with an allogeneic hematopoietic stem cell transplantation. Even though treatment of severe cGVHD has improved during recent years, it remains one of the main causes of morbidity and mortality in affected patients. Biomarkers in blood that could aid in the diagnosis and classification of cGVHD severity are needed for the development of novel treatment strategies that can alleviate symptoms and reduce the need for painful and sometimes complicated tissue biopsies. Methods that comprehensively profile complex biological systems such as the immune system can reveal unanticipated markers when used with the appropriate methods of data analysis. Here, we used mass cytometry, flow cytometry, enzyme-linked immunosorbent assay, and multiplex assays to systematically profile immune cell populations in 68 patients with varying grades of cGVHD. We identified multiple subpopulations across T, B, and NK-cell lineages that distinguished patients with cGVHD from those without cGVHD and which were associated in varying ways with severity of cGVHD. Specifically, initial flow cytometry demonstrated that patients with more severe cGVHD had lower mucosal-associated T cell frequencies, with a concomitant higher level of CD38 expression on T cells. Mass cytometry could identify unique subpopulations specific for cGVHD severity albeit with some seemingly conflicting results. For instance, patients with severe cGVHD had an increased frequency of activated B cells compared to patients with moderate cGVHD while activated B cells were found at a reduced frequency in patients with mild cGVHD compared to patients without cGVHD. Moreover, results indicate it may be possible to validate mass cytometry results with clinically viable, smaller flow cytometry panels. Finally, no differences in levels of blood soluble markers could be identified, with the exception for the semi-soluble combined marker B-cell activating factor/B cell ratio, which was increased in patients with mild cGVHD compared to patients without cGVHD. These findings suggest that interdependencies between such perturbed subpopulations of cells play a role in cGVHD pathogenesis and can serve as future diagnostic and therapeutic targets.