Pilot study to evaluate the safety and effectiveness of etidronate treatment for arterial calcification due to deficiency of CD73 (ACDC).

BACKGROUND: Arterial calcification due to deficiency of CD73 (ACDC; OMIM 211800) is a rare genetic disease resulting in calcium deposits in arteries and small joints causing claudication, resting pain, severe joint pain, and deformities. Currently, there are no standard treatments for ACDC. Our previous work identified etidronate as a potential targeted ACDC treatment, using in vitro and in vivo disease models with patient-derived cells. In this study, we test the safety and effectiveness of etidronate in attenuating the progression of lower-extremity arterial calcification and vascular blood flow based on the computed tomography (CT) calcium score and ankle-brachial index (ABI). METHODS: Seven adult patients with a confirmed genetic diagnosis of ACDC were enrolled in an open-label, nonrandomized, single-arm pilot study for etidronate treatment. They took etidronate daily for 14 days every 3 months and were examined at the NIH Clinical Center bi-annually for 3 years. They received a baseline evaluation as well as yearly follow up after treatment. Study visits included imaging studies, exercise tolerance tests with ABIs, clinical blood and urine testing, and full dental exams. RESULTS: Etidronate treatment appeared to have slowed the progression of further vascular calcification in lower extremities as measured by CT but did not have an effect in reversing vascular and/or periarticular joint calcifications in our small ACDC cohort. CONCLUSIONS: Etidronate was found to be safe and well tolerated by our patients and, despite the small sample size, appeared to show an effect in slowing the progression of calcification in our ACDC patient cohort.(ClinicalTrials.gov Identifier NCT01585402).

TNF inhibition in vasculitis management in adenosine deaminase 2 deficiency (DADA2).

BACKGROUND: Deficiency of adenosine deaminase 2 (DADA2) is a recessively inherited autoinflammatory disorder caused by a loss of functional ADA2 protein. TNF inhibition (TNFi) has proven to be highly effective in treating inflammatory manifestations. OBJECTIVE: We sought to explore the pathophysiology and the underlying mechanisms of TNF-inhibitor response in these patients. METHODS: We performed Sanger sequencing of the ADA2 gene. We used flow cytometry, intracellular cytokine staining, transcriptome analysis, immunohistochemistry, and cell differentiation experiments to define an inflammatory signature in patients with DADA2 and studied their response to TNF-inhibitor treatment. RESULTS: We demonstrated increased inflammatory signals and overproduction of cytokines mediated by IFN and nuclear factor kappa B pathways in patients' primary cells. Treatment with TNFi led to reduction in inflammation, rescued the skewed differentiation toward the proinflammatory M1 macrophage subset, and restored integrity of endothelial cells in blood vessels. We also report 8 novel disease-associated variants in 7 patients with DADA2. CONCLUSIONS: Our data explore the cellular mechanism underlying effective treatment with TNFi therapies in DADA2. DADA2 vasculitis is strongly related to the presence of activated myeloid cells, and the endothelial cell damage is rescued with anti-TNF treatment.

RGC-32' dual role in smooth muscle cells and atherogenesis.

Proliferation of endothelial cells (EC) and smooth muscle cells (SMC) is a critical process in atherosclerosis. Here, we investigated the involvement of sublytic C5b-9 effector Response Gene to Complement 32 (RGC-32) in cell cycle activation, phenotypic switch, and production of extracellular matrix (ECM) in SMC. Overexpression of RGC-32 augmented C5b-9-induced cell cycle activation and proliferation of SMC in an ERK1-dependent manner and silencing of RGC-32 inhibited C5b-9-induced cell cycle activation. C5b-9-induced cell cycle activation also required phosphorylation of RGC-32 at threonine 91. We found that ECM components fibronectin and collagens I-V were expressed by SMC in human aortic atherosclerotic tissue. Silencing of RGC-32 in cultured SMC was followed by a significant reduction in TGF-ß-induced expression of SMC differentiation markers myocardin, SM22 and α-SMA, and that of collagens I, IV and V. These data suggest that RGC-32 participates in both sublytic C5b-9-induced cell cycle activation and TGF-ß-induced ECM production.

Characterization of autoantibodies, immunophenotype and autoimmune disease in a prospective cohort of patients with idiopathic CD4 lymphocytopenia.

OBJECTIVE: Characterize autoantibodies and autoimmune diseases in a prospective cohort of patients with Idiopathic CD4 Lymphocytopenia (ICL) a rare immunodeficiency characterized by an absolute CD4+ T count of <300 cells/µl in the absence of HIV or HTLV infection. METHODS: Single-Center prospective study of 67 patients conducted over an 11-year period. Rheumatologic evaluation and measurement of autoantibodies were systematically conducted, and flow cytometry of immune cell subsets was performed in a subset of patients. RESULTS: 54% of referred patients had clinical evidence of autoimmunity, with 34% having at least one autoimmune disease, most commonly autoimmune thyroid disease. 19%, had autoantibodies or incomplete features of autoimmune disease. Patients with autoimmune disease had more elevated serum immunoglobulins, and more effector memory T cells than those without autoimmunity. CONCLUSIONS: Evidence of autoimmunity, including autoimmune diseases, is more prevalent in ICL than the general population, and should be considered part of this syndrome.

Multifocal calcific periarthritis with distinctive clinical and radiological features in patients with CD73 deficiency.

OBJECTIVES: Arterial calcification due to deficiency of CD73 (ACDC) is a hereditary autosomal recessive ectopic mineralization syndrome caused by loss-of-function mutations in the ecto-5'-nucleotidase gene. Periarticular calcification has been reported but the clinical characterization of arthritis as well as the microstructure and chemical composition of periarticular calcifications and SF crystals has not been systematically investigated. METHODS: Eight ACDC patients underwent extensive rheumatological and radiological evaluation over a period of 11 years. Periarticular and synovial biopsies were obtained from four patients. Characterization of crystal composition was evaluated by compensated polarized light microscopy, Alizarin Red staining for synovial fluid along with X-ray diffraction and X-ray micro tomosynthesis scanner for periarticular calcification. RESULTS: Arthritis in ACDC patients has a clinical presentation of mixed erosive-degenerative joint changes with a median onset of articular symptoms at 17 years of age and progresses over time to the development of fixed deformities and functional limitations of small peripheral joints with, eventually, larger joint and distinct axial involvement later in life. We have identified calcium pyrophosphate and calcium hydroxyapatite (CHA) crystals in SF specimens and determined that CHA crystals are the principal component of periarticular calcifications. CONCLUSION: This is the largest study in ACDC patients to describe erosive peripheral arthropathy and axial enthesopathic calcifications over a period of 11 years and the first to identify the composition of periarticular calcifications and SF crystals. ACDC should be considered among the genetic causes of early-onset OA, as musculoskeletal disease signs may often precede vascular symptoms.

Revisiting TNF Receptor-Associated Periodic Syndrome (TRAPS): Current Perspectives.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) is an autosomal dominant autoinflammatory syndrome characterized by prolonged and recurrent episodes of fever, abdominal and/or chest pain, arthralgia, myalgia, and erythematous rash. TRAPS is associated with heterozygous variants in the TNFRSF1A gene, which encodes the TNFR1 (tumor necrosis factor receptor 1) receptor. Disease-causing variants are found exclusively in the extracellular domain of TNFR1 and affect receptor structure and binding to the TNF ligand. The precise mechanism of the disease is still unclear, but it is thought that intracellular accumulation of misfolded mutant protein leads to endoplasmic reticulum stress and enhanced inflammatory responses through constitutive activation of various immune pathways. Other possible mechanisms contributing to the disease pathogenesis include defective receptor shedding, TNF-induced cell death, production of reactive oxygen species, and autophagy impairment. Patients' leucocytes are hyperresponsive to stimulation and produce elevated levels of proinflammatory cytokines. Systemic autoimmune (AA) amyloidosis is an important cause of morbidity and mortality in TRAPS. Over the last two decades, new therapies have changed the progression and outcome of the disease. In this review, we summarize clinical data from 209 patients with validated pathogenic variants reported in the literature and discuss TRAPS diagnosis, pathogenesis, and treatment options.

CADASIL: new advances in basic science and clinical perspectives.

PURPOSE OF REVIEW: Recent advances in genetic evaluation improved the identification of several variants in the NOTCH3 gene causing Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL). Despite improved diagnosis, the disease mechanism remains an elusive target and an increasing number of scientific/clinical groups are investigating CADASIL to better understand it. The purpose of this review is to summarize the current knowledge in CADASIL. RECENT FINDINGS: CADASIL is a genotypically and phenotypically diverse condition involving multiple molecular systems affecting small blood vessels. Cerebral white matter changes observed by MRI are a key CADASIL characteristic in young adult patients often before severe symptoms and trigger NOTCH3 genetic testing. NOTCH3 mutation locations are highly variable, correlate to disease severity and consistently affect the cysteine balance within extracellular Notch3. Granular osmiophilic material deposits around blood vessels are also a unique CADASIL feature and appear to have a role in sequestering proteins that are essential for blood vessel homeostasis. As potential biomarkers and therapeutic targets are being actively investigated, neurofilament light chain can be detected in patient serum and may be a promising circulating biomarker. SUMMARY: CADASIL is a complex, devastating disease with unknown mechanism and no treatment options. As we increase our understanding of CADASIL, translational research bridging basic science and clinical findings needs to drive biomarker and therapeutic target discovery.

Intracerebral matrix metalloproteinase 9 in fatal diabetic ketoacidosis.

There is increasing awareness that in addition to the metabolic crisis of diabetic ketoacidosis (DKA) caused by severe insulin deficiency, the immune inflammatory response is likely an active multicomponent participant in both the acute and chronic insults of this medical crisis, with strong evidence of activation for both the cytokine and complement system. Recent studies report that the matrix metalloproteinase enzymes and their inhibitors are systemically activated in young Type 1 diabetes mellitus (T1D) patients during DKA and speculate on their involvement in blood-brain barrier (BBB) disruption. Based on our previous studies, we address the question if matrix metalloproteinase 9 (MMP9) is expressed in the brain in the fatal brain edema (BE) of DKA. Our data show significant expression of MMP9 on the cells present in brain intravascular areas. The presence of MMP9 in intravascular cells and that of MMP+ cells seen passing the BBB indicates a possible role in tight junction protein disruption of the BBB, possibly leading to neurological complications including BE. We have also shown that MMP9 is expressed on neurons in the hippocampal areas of both BE/DKA cases investigated, while expression of tissue inhibitor of metalloproteinases 1 (TIMP1) was reduced in the same areas. We can speculate that intraneuronal MMP9 can be a sign of neurodegeneration. Further studies are necessary to determine the role of MMP9 in the pathogenesis of the neurologic catastrophe of the brain edema of DKA. Inhibition of MMP9 expression might be helpful in preserving neuronal function and BBB integrity during DKA.

RGC-32 Promotes Th17 Cell Differentiation and Enhances Experimental Autoimmune Encephalomyelitis.

Th17 cells play a critical role in autoimmune diseases, including multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis. Response gene to complement (RGC)-32 is a cell cycle regulator and a downstream target of TGF-ß that mediates its profibrotic activity. In this study, we report that RGC-32 is preferentially upregulated during Th17 cell differentiation. RGC-32-/- mice have normal Th1, Th2, and regulatory T cell differentiation but show defective Th17 differentiation in vitro. The impaired Th17 differentiation is associated with defects in IFN regulatory factor 4, B cell-activating transcription factor, retinoic acid-related orphan receptor γt, and SMAD2 activation. In vivo, RGC-32-/- mice display an attenuated experimental autoimmune encephalomyelitis phenotype accompanied by decreased CNS inflammation and reduced frequency of IL-17- and GM-CSF-producing CD4+ T cells. Collectively, our results identify RGC-32 as a novel regulator of Th17 cell differentiation in vitro and in vivo and suggest that RGC-32 is a potential therapeutic target in multiple sclerosis and other Th17-mediated autoimmune diseases.

RGC-32 is expressed in the human atherosclerotic arterial wall: Role in C5b-9-induced cell proliferation and migration.

The complement system is an important player in the development of atherosclerosis. Previously reported as a cell cycle regulator, RGC-32 is an essential effector of the terminal complement complex, C5b-9. In this study, our aims were to determine the expression of RGC-32 in the human atherosclerotic arterial wall and to delineate the mechanisms through which RGC-32 affects C5b-9-induced endothelial cell proliferation and migration. We now demonstrate that RGC-32 is expressed in human aortic atherosclerotic wall and that RGC-32 expression increases with the progression of atherosclerosis. Furthermore, silencing of RGC-32 expression abolished C5b-9-induced human aortic endothelial cell (HAEC) proliferation and migration. Of the 279 genes differentially expressed in HAECs after RGC-32 silencing, the genes involved in cell adhesion and cell cycle activation were significantly regulated by RGC-32. RGC-32 silencing caused a significant reduction in the expression of cyclin D1, cyclin D3, Akt, ROCK1, Rho GDP dissociation inhibitor alpha and profilin. These data suggest that RGC-32 mediates HAEC migration through the regulation of RhoA and ROCK1 expression and is involved in actin cytoskeletal organization. Thus, RGC-32 has promising therapeutic potential with regard to angiogenesis and atherosclerosis.

RGC-32 as a potential biomarker of relapse and response to treatment with glatiramer acetate in multiple sclerosis.

Currently there is critical need for the identification of reliable biomarkers to help guide clinical management of multiple sclerosis (MS) patients. We investigated the combined roles of Response Gene to Complement 32 (RGC-32), FasL, CDC2, AKT, and IL-21 as possible biomarkers of relapse and response to glatiramer acetate (GA) treatment in relapsing-remitting MS (RRMS) patients. Over the course of 2 years, a cohort of 15 GA-treated RRMS patients was clinically monitored and peripheral blood mononuclear cells (PBMCs) were collected at 0, 3, 6, and 12 months. Target gene mRNA expression was measured in patients' isolated PBMCs by real-time qRT-PCR. Compared to stable MS patients, those with acute relapses exhibited decreased expression of RGC-32 (p<0.0001) and FasL (p<0.0001), increased expression of IL-21 (p=0.04), but no change in CDC2 or AKT. Compared to non-responders, responders to GA treatment showed increased expression of RGC-32 (p<0.0001) and FasL (p<0.0001), and decreased expression of IL-21 (p=0.02). Receiver operating characteristic (ROC) analysis was used to assess the predictive accuracy of each putative biomarker. The probability of accurately detecting relapse was 90% for RGC-32, 88% for FasL, and 75% for IL-21. The probability of accurately detecting response to GA was 85% for RGC-32, 90% for FasL, and 85% for IL-21. Our data suggest that RGC-32, FasL, and IL-21 could serve as potential biomarkers for the detection of MS relapse and response to GA therapy.

RGC-32 is a novel regulator of the T-lymphocyte cell cycle.

We have previously shown that RGC-32 is involved in cell cycle regulation in vitro. To define the in vivo role of RGC-32, we generated RGC-32 knockout mice. These mice developed normally and did not spontaneously develop overt tumors. To assess the effect of RGC-32 deficiency on cell cycle activation in T cells, we determined the proliferative rates of CD4(+) and CD8(+) T cells from the spleens of RGC-32(-/-) mice, as compared to wild-type (WT, RGC-32(+/+)) control mice. After stimulation with anti-CD3/anti-CD28, CD4(+) T cells from RGC-32(-/-) mice displayed a significant increase in [(3)H]-thymidine incorporation when compared to WT mice. In addition, both CD4(+) and CD8(+) T cells from RGC-32(-/-) mice displayed a significant increase in the proportion of proliferating Ki67(+) cells, indicating that in T cells, RGC-32 has an inhibitory effect on cell cycle activation induced by T-cell receptor/CD28 engagement. Furthermore, Akt and FOXO1 phosphorylation induced in stimulated CD4(+) T-cells from RGC-32(-/-) mice were significantly higher, indicating that RGC-32 inhibits cell cycle activation by suppressing FOXO1 activation. We also found that IL-2 mRNA and protein expression were significantly increased in RGC-32(-/-) CD4(+) T cells when compared to RGC-32(+/+) CD4(+) T cells. In addition, the effect of RGC-32 on the cell cycle and IL-2 expression was inhibited by pretreatment of the samples with LY294002, indicating a role for phosphatidylinositol 3-kinase (PI3K). Thus, RGC-32 is involved in controlling the cell cycle of T cells in vivo, and this effect is mediated by IL-2 in a PI3K-dependent fashion.

SIRT1 is decreased during relapses in patients with multiple sclerosis.

SIRT1 is a member of the histone deacetylase (HDAC) class III family of proteins and is an NAD-dependent histone and protein deacetylase. SIRT1 can induce chromatin silencing through the deacetylation of histones and can modulate cell survival by regulating the transcriptional activities. We investigated the expression of SIRT1 in multiple sclerosis (MS) brains and in peripheral blood mononuclear cells (PBMCs) obtained from patients with relapsing-remitting multiple sclerosis. We found that SIRT1 was expressed by a significant number of cells in both acute and chronic active lesions. We also found that CD4(+), CD68(+), oligodendrocytes (OLG), and glial fibrillar acidic protein (GFAP)(+) cells in MS plaques co-localized with SIRT1. Our results show a statistically significant decrease in SIRT1 mRNA and protein expression in PBMCs during relapses when compared to the levels in controls and stable MS patients. On the other hand, HDAC3 expression was not significantly changed during relapses in MS patients. SIRT1 expression correlated with that of histone H3 lysine 9 acetylation (H3K9ac) and methylation (H3K9me2). SIRT1 mRNA expression was significantly reduced after RGC-32 silencing, indicating a role for RGC-32 in the regulation of SIRT1 expression. Furthermore, we investigated the role of SIRT1 in the expression of FasL and found a significant increase in FasL expression and apoptosis after inhibition of SIRT1 expression. Our data suggest that SIRT1 may represent a biomarker of relapses and a potential new target for therapeutic intervention in MS.

A unified metric of human immune health.

Immunological health has been challenging to characterize but could be defined as the absence of immune pathology. While shared features of some immune diseases and the concept of immunologic resilience based on age-independent adaptation to antigenic stimulation have been developed, general metrics of immune health and its utility for assessing clinically healthy individuals remain ill defined. Here we integrated transcriptomics, serum protein, peripheral immune cell frequency and clinical data from 228 patients with 22 monogenic conditions impacting key immunological pathways together with 42 age- and sex-matched healthy controls. Despite the high penetrance of monogenic lesions, differences between individuals in diverse immune parameters tended to dominate over those attributable to disease conditions or medication use. Unsupervised or supervised machine learning independently identified a score that distinguished healthy participants from patients with monogenic diseases, thus suggesting a quantitative immune health metric (IHM). In ten independent datasets, the IHM discriminated healthy from polygenic autoimmune and inflammatory disease states, marked aging in clinically healthy individuals, tracked disease activities and treatment responses in both immunological and nonimmunological diseases, and predicted age-dependent antibody responses to immunizations with different vaccines. This discriminatory power goes beyond that of the classical inflammatory biomarkers C-reactive protein and interleukin-6. Thus, deviations from health in diverse conditions, including aging, have shared systemic immune consequences, and we provide a web platform for calculating the IHM for other datasets, which could empower precision medicine.

Dual role of Response gene to complement-32 in multiple sclerosis.

Response gene to complement (RGC)-32 is a novel molecule that plays an important role in cell proliferation. We investigated the expression of RGC-32 in multiple sclerosis (MS) brain and in peripheral blood mononuclear cells (PBMCs) obtained from patients with relapsing-remitting multiple sclerosis. We found that CD3(+), CD68(+), and glial fibrillar acidic protein (GFAP)(+) cells in MS plaques co-localized with RGC-32. Our results show a statistically significant decrease in RGC-32 mRNA expression in PBMCs during relapses when compared to the levels in stable MS patients. This decrease might be useful in predicting disease activity in patients with relapsing-remitting MS. RGC-32 expression was also correlated with that of FasL mRNA during relapses. FasL mRNA expression was significantly reduced after RGC-32 silencing, indicating a role for RGC-32 in the regulation of FasL expression. In addition, the expression of Akt1, cyclin D1, and IL-21 mRNA was significantly increased during MS relapses when compared to levels in healthy controls. Furthermore, we investigated the role of RGC-32 in TGF-ß-induced extracellular matrix expression in astrocytes. Blockage of RGC-32 using small interfering RNA significantly inhibits TGF-ß induction of procollagen I, fibronectin and of the reactive astrocyte marker α-smooth muscle actin (α-SMA). Our data suggest that RGC-32 plays a dual role in MS, both as a regulator of T-cells mediated apoptosis and as a promoter of TGF-ß-mediated profibrotic effects in astrocytes.

Multiomics integration of 22 immune-mediated monogenic diseases reveals an emergent axis of human immune health.

Monogenic diseases are often studied in isolation due to their rarity. Here we utilize multiomics to assess 22 monogenic immune-mediated conditions with age- and sex-matched healthy controls. Despite clearly detectable disease-specific and "pan-disease" signatures, individuals possess stable personal immune states over time. Temporally stable differences among subjects tend to dominate over differences attributable to disease conditions or medication use. Unsupervised principal variation analysis of personal immune states and machine learning classification distinguishing between healthy controls and patients converge to a metric of immune health (IHM). The IHM discriminates healthy from multiple polygenic autoimmune and inflammatory disease states in independent cohorts, marks healthy aging, and is a pre-vaccination predictor of antibody responses to influenza vaccination in the elderly. We identified easy-to-measure circulating protein biomarker surrogates of the IHM that capture immune health variations beyond age. Our work provides a conceptual framework and biomarkers for defining and measuring human immune health.

C5b-9-activated, K(v)1.3 channels mediate oligodendrocyte cell cycle activation and dedifferentiation.

Voltage-gated potassium (K(v)) channels play an important role in the regulation of growth factor-induced cell proliferation. We have previously shown that cell cycle activation is induced in oligodendrocytes (OLGs) by complement C5b-9, but the role of K(v) channels in these cells had not been investigated. Differentiated OLGs were found to express K(v)1.4 channels, but little K(v)1.3. Exposure of OLGs to C5b-9 modulated K(v)1.3 functional channels and increased protein expression, whereas C5b6 had no effect. Pretreatment with the recombinant scorpion toxin rOsK-1, a highly selective K(v)1.3 inhibitor, blocked the expression of K(v)1.3 induced by C5b-9. rOsK-1 inhibited Akt phosphorylation and activation by C5b-9 but had no effect on ERK1 activation. These data strongly suggest a role for K(v)1.3 in controlling the Akt activation induced by C5b-9. Since Akt plays a major role in C5b-9-induced cell cycle activation, we also investigated the effect of inhibiting K(v)1.3 channels on DNA synthesis. rOsK-1 significantly inhibited the DNA synthesis induced by C5b-9 in OLG, indicating that K(v)1.3 plays an important role in the C5b-9-induced cell cycle. In addition, C5b-9-mediated myelin basic protein and proteolipid protein mRNA decay was completely abrogated by inhibition of K(v)1.3 expression. In the brains of multiple sclerosis patients, C5b-9 co-localized with NG2(+) OLG progenitor cells that expressed K(v)1.3 channels. Taken together, these data suggest that K(v)1.3 channels play an important role in controlling C5b-9-induced cell cycle activation and OLG dedifferentiation, both in vitro and in vivo.

RGC-32 Acts as a Hub to Regulate the Transcriptomic Changes Associated With Astrocyte Development and Reactive Astrocytosis.

Response Gene to Complement 32 (RGC-32) is an important mediator of the TGF-ß signaling pathway, and an increasing amount of evidence implicates this protein in regulating astrocyte biology. We showed recently that spinal cord astrocytes in mice lacking RGC-32 display an immature phenotype reminiscent of progenitors and radial glia, with an overall elongated morphology, increased proliferative capacity, and increased expression of progenitor markers when compared to their wild-type (WT) counterparts that make them incapable of undergoing reactive changes during the acute phase of experimental autoimmune encephalomyelitis (EAE). Here, in order to decipher the molecular networks underlying RGC-32's ability to regulate astrocytic maturation and reactivity, we performed next-generation sequencing of RNA from WT and RGC-32 knockout (KO) neonatal mouse brain astrocytes, either unstimulated or stimulated with the pleiotropic cytokine TGF-ß. Pathway enrichment analysis showed that RGC-32 is critical for the TGF-ß-induced up-regulation of transcripts encoding proteins involved in brain development and tissue remodeling, such as axonal guidance molecules, transcription factors, extracellular matrix (ECM)-related proteins, and proteoglycans. Our next-generation sequencing of RNA analysis also demonstrated that a lack of RGC-32 results in a significant induction of WD repeat and FYVE domain-containing protein 1 (Wdfy1) and stanniocalcin-1 (Stc1). Immunohistochemical analysis of spinal cords isolated from normal adult mice and mice with EAE at the peak of disease showed that RGC-32 is necessary for the in vivo expression of ephrin receptor type A7 in reactive astrocytes, and that the lack of RGC-32 results in a higher number of homeodomain-only protein homeobox (HOPX)+ and CD133+ radial glia cells. Collectively, these findings suggest that RGC-32 plays a major role in modulating the transcriptomic changes in astrocytes that ultimately lead to molecular programs involved in astrocytic differentiation and reactive changes during neuroinflammation.

The Spectrum of the Deficiency of Adenosine Deaminase 2: An Observational Analysis of a 60 Patient Cohort.

The deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessively inherited disease that has undergone extensive phenotypic expansion since being first described in patients with fevers, recurrent strokes, livedo racemosa, and polyarteritis nodosa in 2014. It is now recognized that patients may develop multisystem disease that spans multiple medical subspecialties. Here, we describe the findings from a large single center longitudinal cohort of 60 patients, the broad phenotypic presentation, as well as highlight the cohort's experience with hematopoietic cell transplantation and COVID-19. Disease manifestations could be separated into three major phenotypes: inflammatory/vascular, immune dysregulatory, and hematologic, however, most patients presented with significant overlap between these three phenotype groups. The cardinal features of the inflammatory/vascular group included cutaneous manifestations and stroke. Evidence of immune dysregulation was commonly observed, including hypogammaglobulinemia, absent to low class-switched memory B cells, and inadequate response to vaccination. Despite these findings, infectious complications were exceedingly rare in this cohort. Hematologic findings including pure red cell aplasia (PRCA), immune-mediated neutropenia, and pancytopenia were observed in half of patients. We significantly extended our experience using anti-TNF agents, with no strokes observed in 2026 patient months on TNF inhibitors. Meanwhile, hematologic and immune features had a more varied response to anti-TNF therapy. Six patients received a total of 10 allogeneic hematopoietic cell transplant (HCT) procedures, with secondary graft failure necessitating repeat HCTs in three patients, as well as unplanned donor cell infusions to avoid graft rejection. All transplanted patients had been on anti-TNF agents prior to HCT and received varying degrees of reduced-intensity or non-myeloablative conditioning. All transplanted patients are still alive and have discontinued anti-TNF therapy. The long-term follow up afforded by this large single-center study underscores the clinical heterogeneity of DADA2 and the potential for phenotypes to evolve in any individual patient.