Monogenic Immune Diseases Provide Insights Into the Mechanisms and Treatment of Chronic Graft-Versus-Host Disease

A likely case of chronic graft-versus-host disease polymyositis affecting respiratory and truncal muscles - a comprehensive diagnostic approach

Background

Muscle involvement, termed polymyositis, is an uncommon manifestation of graft-versus-host disease (GvHD) in which the upper and lower limbs are commonly affected. However, respiratory failure due to diaphragmatic weakness has rarely been reported. Diagnosis is usually based on a combination of elevated muscle enzyme levels in the blood, neurophysiological studies, and muscle biopsies.

Case report

A 23-year-old man who presented with Philadelphia chromosome (Ph)-positive chronic myeloid leukemia in myeloid blast crisis, underwent HLA-matched sibling (sister) hematopoietic stem cell transplantation. Six months post-transplant, he experienced bilateral arm pain and weakness, with an inability to raise his limbs against gravity. He was also unable to sit erect, and was dyspneic and hypoxic, thus requiring oxygen supplementation. Serum muscle enzyme levels were found to be markedly elevated. Magnetic resonance imaging showed a patchy hyperintense T2-weighted signal and enhancement in the muscle groups of the limbs, as well as in the psoas and erector spinae muscles. The electromyogram results were consistent with those of inflammatory myopathy. Muscle biopsy revealed extensive necrotizing myositis with extensive lymphocyte infiltration throughout the muscle fascicle. Additionally, fluorescence in situ hybridization (FISH) analysis demonstrated that 30% of the nuclei scored were in the muscle fibers of recipient XY origin, and 70% were in T-lymphocytes of donor XX origin. GvHD polymyositis was diagnosed, and the patient responded well to corticosteroids and extracorporeal photopheresis.

Conclusion

GvHD polymyositis can affect various muscle groups and results in various clinical presentations. In our case, truncal involvement resulting in an inability to sit erect was a unique presentation. Prompt diagnosis is important, and we have highlighted a comprehensive multimodal approach, including the potential use of FISH analysis, to aid in diagnosis.

Chronic graft-versus-host disease detected by tissue-specific cell-free DNA methylation biomarkers

BACKGROUND

Accurate detection of graft-versus-host disease (GVHD) is a major challenge in the management of patients undergoing hematopoietic stem cell transplantation (HCT). Here, we demonstrated the use of circulating cell-free DNA (cfDNA) for detection of tissue turnover and chronic GVHD (cGVHD) in specific organs.

METHODS

We established a cocktail of tissue-specific DNA methylation markers and used it to determine the concentration of cfDNA molecules derived from the liver, skin, lungs, colon, and specific immune cells in 101 patients undergoing HCT.

RESULTS

Patients with active cGVHD showed elevated concentrations of cfDNA, as well as tissue-specific methylation markers that agreed with clinical scores. Strikingly, transplanted patients with no clinical symptoms had abnormally high levels of tissue-specific markers, suggesting hidden tissue turnover even in the absence of evident clinical pathology. An integrative model taking into account total cfDNA concentration, monocyte/macrophage cfDNA levels and alanine transaminase was able to correctly identify GVHD with a specificity of 86% and precision of 89% (AUC of 0.8).

CONCLUSION

cfDNA markers can be used for the detection of cGVHD, opening a window into underlying tissue dynamics in patients that receive allogeneic stem cell transplants.

FUNDING

This work was supported by grants from the Ernest and Bonnie Beutler Research Program of Excellence in Genomic Medicine, The Israel Science Foundation, the Waldholtz/Pakula family, the Robert M. and Marilyn Sternberg Family Charitable Foundation and the Helmsley Charitable Trust (to YD).

Neoself Antigens Presented on MHC Class II Molecules in Autoimmune Diseases

Major histocompatibility complex (MHC) class II molecules play a crucial role in immunity by presenting peptide antigens to helper T cells. Immune cells are generally tolerant to self-antigens. However, when self-tolerance is broken, immune cells attack normal tissues or cells, leading to the development of autoimmune diseases. Genome-wide association studies have shown that MHC class II is the gene most strongly associated with the risk of most autoimmune diseases. When misfolded self-antigens, called neoself antigens, are associated with MHC class II molecules in the endoplasmic reticulum, they are transported by the MHC class II molecules to the cell surface without being processed into peptides. Moreover, neoself antigens that are complexed with MHC class II molecules of autoimmune disease risk alleles exhibit distinct antigenicities compared to normal self-antigens, making them the primary targets of autoantibodies in various autoimmune diseases. Elucidation of the immunological functions of neoself antigens presented on MHC class II molecules is crucial for understanding the mechanism of autoimmune diseases.

Antibody-mediated pathogenesis of chronic GVHD through DBY/HLA class II complexes and induction of a GVL effect

Chronic graft-versus-host disease (cGVHD) is a multiorgan syndrome with clinical features resembling those of autoimmune diseases. Thus, understanding commonalities in the pathophysiology of cGVHD and autoimmune diseases, such as the presence of disease-risk HLA alleles, is imperative for developing novel therapies against cGVHD. Alloantibodies against H-Y antigens encoded on the Y-chromosome are well-described risk factors for cGVHD in female-to-male transplantation. However, because H-Y antigens generally localize intracellularly in the male reproductive organs, how they emerge at affected organ levels remains elusive. Here, by analyzing nationwide registry data stratified per donor-recipient sex, we identified specific HLA class II alleles that contributed to susceptibility to male cGVHD after transplantation from HLA-identical female siblings (HLA-DRB1∗15:02: hazard ratio, 1.28; 95% confidence interval, 1.03-1.58; P = .025). Coexpression of HLA-DRB1∗15:02 efficiently transported full-length H-Y antigens, especially DBY, to the surface. The presence of alloantibodies against DBY/HLA class II complexes significantly predicted the occurrence of cGVHD (68.8% vs 31.7% at 1 year; P = .002). Notably, the ability of HLA class II molecules to transport and present DBY to alloantibodies was closely associated with the susceptibility of HLA class II alleles to cGVHD. DBY specifically colocalized with HLA class II molecules on the dermal vascular endothelium in cGVHD and provoked complement-dependent cytotoxicity. Moreover, these complexes were observed in some male leukemic cells. Altogether, these findings suggest that vascular endothelial cells facilitate alloantibody-mediated cGVHD and highlight that alloantibodies against DBY/HLA class II complexes could be common targets for cGVHD and a graft-versus-leukemia effect.

Elevated ADA2 Enzyme Activity at the Onset of Chronic Graft-versus-Host Disease in Children

Adenosinergic signaling has potent, context-specific effects on immune cells, particularly on the dysregulation of lymphocytes. This in turn may have a role in immune activation and loss of tolerance in such diseases as chronic graft-versus-host disease (chronic GVHD). We assessed whether changes in the enzymatic activity of adenosine deaminase 2 (ADA2), an enzyme that depletes adenosine in the extracellular space via conversion to inosine, may be associated with the onset of chronic GVHD. ADA2-specific enzyme activity was measured in plasma samples from 230 pediatric hematopoietic stem cell transplantation (HSCT) recipients enrolled on the Applied Biomarkers of Late Effects of Childhood Cancer (ABLE)/Pediatric Blood and Marrow Transplant Consortium (PBMTC) 1202 study and compared between patients developing chronic GVHD and those not developing chronic GVHD within 12 months of transplantation. ADA2 and its relationships with 219 previously measured plasma-soluble proteins, metabolites, and immune cell populations were evaluated as well. Plasma ADA2 enzyme activity was significantly elevated in pediatric HSCT recipients at the onset of chronic GVHD compared to patients without chronic GVHD and was not associated with prior history of acute GVHD or generalized inflammation as measured by C-reactive protein concentration. ADA2-specific enzyme activity met our criteria as a potential diagnostic biomarker of chronic GVHD (effect ratio ≥1.30 or ≤.75; area under the receiver operating characteristic curve ≥.60; P < .05) and was positively associated with markers of immune activation previously identified in pediatric chronic GVHD patients. These results support the potential of ADA2 enzyme activity, in combination with other biomarkers and subject to future validation, to aid the diagnosis of chronic GVHD in children post-HSCT.

Effect of ruxolitinib on the oral mucosa of patients with steroid-refractory chronic Graft-versus-Host disease and oral involvement

BACKGROUND

Chronic Graft-versus-Host Disease (cGVHD) can impact quality of life, especially in patients with oral involvement. Half of the patients with cGVHD do not respond to first-line therapy with corticosteroids and calcineurin inhibitors. Ruxolitinib is effective in steroid-refractory (SR)-cGVHD cases, but the long-term effects of ruxolitinib on the oral mucosa are unknown.

OBJECTIVE(S)

This study aims to assess the effect of ruxolitinib on the oral mucosa of SR-cGVHD patients with oral involvement.

MATERIALS AND METHODS

An observational longitudinal patient study was conducted in 53 patients with SR-cGVHD and oral involvement who were treated with ruxolitinib. The baseline condition of the oral mucosa was compared to its condition at 4 and 12 weeks after starting ruxolitinib.

RESULTS

The overall response was 81% (43/53), with a complete response in 53% (28/53) and partial response in 28% (15/53) after 12 weeks (p < 0.001). Men and patients concurrently using immunosuppressive therapy responded better than women (p = 0.005) and patients with ruxolitinib monotherapy (p = 0.02), respectively. At a longer follow-up (median 20 months), oral symptoms were comparable to the 12-week symptoms (p = 0.78), regardless of ruxolitinib use (p = 0.83).

CONCLUSION

Ruxolitinib treatment of SR-cGVHD patients with oral involvement was associated with a significant response of the oral manifestations at 12 weeks.

CLINICAL RELEVANCE

The oral mucosa of SR-cGVHD patients is likely to improve after 4 and 12 weeks of ruxolitinib treatment. Symptom severity at baseline does not affect the response of the oral mucosa.

Management of Chronic Graft-vs.-Host Disease in Children and Adolescents With ALL: Present Status and Model for a Personalised Management Plan

Herein we review current practice regarding the management of chronic graft-vs.-host disease (cGvHD) in paediatric patients after allogeneic haematopoietic stem cell transplantation (HSCT) for acute lymphoblastic leukaemia (ALL). Topics covered include: (i) the epidemiology of cGvHD; (ii) an overview of advances in our understanding cGvHD pathogenesis; (iii) current knowledge regarding risk factors for cGvHD and prevention strategies complemented by biomarkers; (iii) the paediatric aspects of the 2014 National Institutes for Health-defined diagnosis and grading of cGvHD; and (iv) current options for cGvHD treatment. We cover topical therapy and newly approved tyrosine kinase inhibitors, emphasising the use of immunomodulatory approaches in the context of the delicate counterbalance between immunosuppression and immune reconstitution as well as risks of relapse and infectious complications. We examine real-world approaches of response assessment and tapering schedules of treatment. Furthermore, we report on the optimal timepoints for therapeutic interventions and changes in relation to immune reconstitution and risk of relapse/infection. Additionally, we review the different options for anti-infectious prophylaxis. Finally, we put forth a theory of a holistic view of paediatric cGvHD and its associated manifestations and propose a checklist for individualised risk evaluation with aggregated considerations including site-specific cGvHD evaluation with attention to each individual's GvHD history, previous medical history, comorbidities, and personal tolerance and psychosocial circumstances. To complement this checklist, we present a treatment algorithm using representative patients to inform the personalised management plans for patients with cGvHD after HSCT for ALL who are at high risk of relapse.