Mitf regulates gene expression networks implicated in B cell homeostasis, germinal center responses, and tolerance.

Introduction: The microphthalmia transcription factor Mitf has been shown to regulate B cell activation and tolerance. However, the underlying B cell-specific mechanisms responsible, and those that distinguish Mitf from closely related Mitf/TFE (MiT) transcription factors Tfe3, Tfeb, and Tfec, remain obscure. Methods: Two complementary mouse models of Mitf and MiT deficiency were used: the Mitfmi-vga9/mi-vga9 systemic loss-of-function mutation, and B-cell specific MiT family inactivation via transgenic expression of a trans-dominant negative (TDN) protein (TDN-B). These models were employed to identify MiT family candidate target genes and pathways. Results: Both models displayed spontaneous splenomegaly coincident with elevated plasma cell numbers, autoantibody titers, and proteinuria. These abnormalities appeared dependent on T helper cells, but independent of other non-B cell intrinsic effects of systemic Mitf inactivation. MiT inactivation in B cells augmented aspects of lupus-like autoimmune disease on the C57BL/6-Faslpr/lpr background. In both models, RNAseq of ex vivo resting B cells showed transcriptional upregulation of genes that control cell cycle, germinal center responses, and plasma cell differentiation. Among the genes strongly upregulated in both models were Socs6, Isp53 (Baiap1), S1pR2, and IgG2b/c. Mitf null B cells, but not TDN-B cells, showed evidence of type I interferon dysregulation. Discussion: These studies clarify Mitf's role as 1) a key regulator of a B cell intrinsic germinal center program that influences self-tolerance through novel target genes, and 2) a regulator of systemic inflammatory processes that can impact the B cell microenvironment. This distinction of Mitf's function from that of related MiT transcription factors advances our understanding of B cell regulation and autoimmunity.

The gut microbiome in systemic lupus erythematosus: lessons from rheumatic fever.

For more than a century, certain bacterial infections that can breach the skin and mucosal barriers have been implicated as common triggers of autoimmune syndromes, especially post-infection autoimmune diseases that include rheumatic fever and post-streptococcal glomerulonephritis. However, only in the past few years has the importance of imbalances within our own commensal microbiota communities, and within the gut, in the absence of infection, in promoting autoimmune pathogenesis become fully appreciated. A diversity of species and mechanisms have been implicated, including disruption of the gut barrier. Emerging data suggest that expansions (or blooms) of pathobiont species are involved in autoimmune pathogenesis and stimulate clonal expansion of T cells and B cells that recognize microbial antigens. This Review discusses the relationship between the gut microbiome and the immune system, and the potential consequence of disrupting the community balance in terms of autoimmune development, focusing on systemic lupus erythematosus. Notably, inter-relationships between expansions of certain members within gut microbiota communities and concurrent autoimmune responses bear features reminiscent of classical post-infection autoimmune disease. From such insights, new therapeutic opportunities are being considered to restore the balance within microbiota communities or re-establishing the gut-barrier integrity to reinforce immune homeostasis in the host.

Understanding the roles of the microbiome in autoimmune rheumatic diseases.

The gut microbiome represents a potential promising therapeutic target for autoimmune diseases. This review summarizes the current knowledge on the links between the gut microbiome and several autoimmune rheumatic diseases including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) spondyloarthropathies (SpA), Sjogren's syndrome (SS), and systemic sclerosis (SSc). Evidence from studies of RA and SLE patients suggests that alterations in the gut microbiome composition and function contribute to disease development and progression through increased gut permeability, with microbes and microbial metabolites driving an excessive systemic activation of the immune system. Also, there is growing evidence that gut dysbiosis and subsequent immune cell activation may contribute to disease pathogenesis in SpA and SS. For SSc, there are fewer, but these are still informative, reports on alterations in the gut microbiome. In general, the complex interplay between the microbiome and the immune system is still not fully understood. Here we discuss the current knowledge of the link between the gut microbiome and autoimmune rheumatic diseases, highlighting potentially fertile areas for future research and make considerations on the potential benefits of strategies that restore gut microbiome homeostasis.

Challenges of caring for transgender and gender diverse patients with rheumatic disease: presentation of seven patients and review of the literature.

PURPOSE OF REVIEW: As perspectives on sex and gender identity have evolved, there has been an increase in the practice of transgender medicine. Within rheumatology, however, there is a dearth of information about rheumatic disease in transgender and gender diverse (TGGD) individuals. This is important, as sex hormones affect the etiopathogenesis and expression of autoimmune diseases. We therefore sought to identify TGGD patients with rheumatic disease, review their clinical courses, and appraise existing literature about this population. RECENT FINDINGS: Of 1053 patients seen at the Los Angeles County and University of Southern California Medical Center from 2019 through 2021, five transgender men and two transgender women with rheumatic disease were identified. Most patients' disease courses were not overtly impacted by gender affirming hormone therapy (GAHT). Six of seven patients had psychosocial barriers to care. Our systematic review found 11 studies with 11 transgender women and two transgender men. In 12 of 13 patients, GAHT possibly modulated the patients' rheumatic disease. SUMMARY: Our observations suggest GAHT need not be a strict contraindication in TGGD patients with rheumatic disease. TGGD patients often face significant psychosocial barriers. Additional information about this population and empathy toward their health disparities are needed.

Predictors of overlapping autoimmune disease in Neuromyelitis Optica Spectrum disorder (NMOSD): A retrospective analysis in two inner-city hospitals.

BACKGROUND: The coexistence of Neuromyelitis Optica spectrum disorder (NMOSD) with other autoimmune diseases (AD-NMOSD) presents worse clinical outcomes and healthcare costs than NMOSD alone (NMOSD-only). NMOSD and other autoimmune diseases also have a higher prevalence and morbidity in Black. We aim to compare clinical features and treatment responses in NMOSD patients with and without overlapping autoimmunity in a predominantly Black cohort. We further identify predictors associated with each clinical subtype. METHODS: AD-NMOSD (n = 14) and NMOSD-only (n = 27) patients were identified retrospectively. Demographic, clinical, laboratory, imaging, and response to treatment data were examined. RESULTS: Our cohort was predominately Black (82.9%). The prevalence of grouped-comorbidities, history of infections, sensory symptoms, Expanded Disability Status Scale (EDSS) before treatment, double-stranded DNA, antinuclear, ribonucleoprotein, and antiphospholipid antibodies, spinal-cord edema, white matter occipital lesions, and the levels of C-reactive protein, urine protein/creatinine, white blood cell count in cerebrospinal fluid (CSF), were higher in AD-NMOSD patients (p < 0.05 and/or Cramer's V > 30, Cohen's d > 50), whereas the age of males, visual symptoms, serum albumin, platelet count, and optic nerve enhancement were lower. EDSS after treatment improved in both groups being more evident in NMOSD-only patients (p = 0.003, SE = 0.58 vs p = 0.075, SE = 0.51). Other variables had a close to moderate SE, and others did not differ between NMOSD subtypes. A higher frequency of grouped-comorbidities, lower serum albumin, and platelet count were independently associated with a higher risk for AD-NMOSD. CONCLUSIONS: Some clinical features between AD-NMOSD and NMOSD-only patients were similar, while others differed. Comorbidities, serum albumin, and platelet count may be independent predictors of AD-NMOSD.

Reflecting on the immunopathology of arthritis associated with inflammatory bowel disease: what do we know and what should we know?

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is clinically closely associated with arthritis. Three major arthritis clinical subtypes have been described, peripheral arthritis type 1 (PeA1), peripheral arthritis type 2 (PeA2), and axial spondyloarthritis (axSpA). While genetic overlaps between IBD and arthritis have been defined, detailed pathophysiology for these three major subtypes of arthritis in patients with IBD has only recently begun to be established. The genetic and molecular mechanisms distinguishing axial and peripheral arthropathies in patients with UC and CD need to be better described. Understanding the pathophysiology for PeA1, PeA2, and axSpA in the settings of both UC and CD is necessary to provide the fundamental biology underlying the clinical phenotypes in IBD arthritis. This has been attempted for CD-associated spondyloarthritis, differentiating this from both CD and axSpA, while observing unique peripheral blood mononuclear cells linking gut inflammation to joint disease. We should know more about the processes by which immune cells are perturbed in these disorders, how they translocate to joints, how they are activated, what other molecules and mediators are involved, and how gut microbes and microbial products damage joints. Information from such studies are needed to elucidate whether distinctions between IBD-related peripheral and axSpA are clinically meaningful. IBD-related peripheral and axSpA studies are needed to elucidate whether distinctions between peripheral and axSpA are clinically meaningful, to better understand immunopathogenesis, and to develop novel targeted therapies.

Challenges of caring for homeless patients with inflammatory arthritis: 12-month follow-up observations and identification of certain barriers to care.

Homelessness is a public health crisis and there is a paucity of information about patients with rheumatic disease experiencing homelessness. We sought to develop approaches to improve care for this unique patient population. We previously reported observations on 17 homeless patients with inflammatory arthritis (15 rheumatoid arthritis (RA), 2 psoriatic arthritis (PsA)). We obtained follow-up information from our original 17 patients and compared this to data summarized and published about them from 12 months previously. We also created and administered a 100-question needs assessment survey. Follow-up 12-month clinical information was available from 13/17 homeless and 13/17 non-homeless controls. Homeless patients remained less well with more disease than non-homeless patients-poorer access to clinic appointments (80% vs 91%, p < 0.05), more emergency services use (20 vs 5 ED visits), less DMARDs use (43% vs 100%, p < 0.01), and more steroid use (29% vs 0%, p < 0.01). Homeless patients also had higher inflammatory markers than non-homeless patients (ESR 32 vs 26 mm/h and CRP 17 vs 5 mg/L), although these findings were not statistically significantly different. Seventy-eight percent of homeless patients were stable, 14% improved, and 7% worse; 21% had stable controlled and 57% stable active disease vs 62% and 0% of non-homeless (p < 0.01). Among the homeless, 6 (4 RA, 2 PsA) completed the survey, 2 declined, and 9 could not be reached. All 6 had found housing although all still had housing insecurity; 4 (67%) were homeless in the past. Three out of six (50%) obtained housing from social assistance during hospitalization following disease exacerbation while homeless. The average monthly income was $873. 5/6 (83.3%), were unable to work due to health, and were in considerable pain that adversely impacted their physical and mental health and ability to perform ADLs. Their perceived "greatest need" included dental care, physical therapy, knee surgery, employment, socialization secondary to isolation, and stable housing. Our understanding of the unique challenges of patients with rheumatic disease experiencing homelessness is improved, but not complete. Strengthened collaboration between street medicine providers and rheumatologists is necessary to improve care for homeless patients, especially given poorer outcomes compared with non-homeless counterparts. Key Points • We report 12-month follow-up information from our original 17 homeless patients with inflammatory arthritis (related in this journal in 2021) and their responses to an extensive needs assessment survey designed to identify barriers to care. • Homeless patients with inflammatory arthritis continued to have worse disease outcomes, use more corticosteroids and less DMARDs, and be seen less often in rheumatology clinics and more frequently in emergency departments than their non-homeless counterparts. • Survey data indicated that social assistance during hospitalization was a key area where healthcare providers could intervene to provide housing security for homeless patients and improve outcomes. Patients perceived "greatest needs" went beyond housing and rheumatological care and critically included access to social/specialty services. • Street medicine is the direct delivery of healthcare to people experiencing homelessness wherever they reside. Our observations, obtained in collaboration with street medicine colleagues, suggest important and salutary opportunities for this partnership to improve care for these particular patients.

Chronic Pain in Patients with Rheumatoid Arthritis.

PURPOSE OF REVIEW: Chronic pain is highly prevalent in patients with rheumatoid arthritis (RA) and can cause various physical and psychological impairments. Unfortunately, the appropriate diagnosis of chronic pain syndromes in this population can be challenging because pain may be primary to RA-specific inflammation and/or secondary to other conditions, typically osteoarthritis (OA) and fibromyalgia (FM). This disparity further poses a clinical challenge, given that chronic pain can often be discordant or undetected with standard RA-specific surveillance strategies, including serological markers and imaging studies. In this review, we provide a robust exploration of chronic pain in the RA population with emphasis on epidemiology, mechanisms, and management strategies. RECENT FINDINGS: Chronic pain associated with RA typically occurs in patients with anxiety, female sex, and elevated inflammatory status. Up to 50% of these patients are thought to have chronic pain despite appropriate inflammatory suppression, typically due to peripheral and central sensitization as well as secondary OA and FM. In addition to the standard-of-care management for OA and FM, patients with RA and chronic pain benefit from behavioral and psychological treatment options. Moreover, early and multimodal therapies, including non-pharmacological, pharmacological, interventional, and surgical strategies, exist, albeit with varying efficacy, to help suppress inflammation, provide necessary analgesia, and optimize functional outcomes. Overall, chronic pain in RA is a difficult entity for both patients and providers. Early diagnosis, improved understanding of its mechanisms, and initiation of early, targeted approaches to pain control may help to improve outcomes in this population.

A Panoply of Rheumatological Manifestations in Patients with GATA2 Deficiency.

PURPOSE: To characterize rheumatological manifestations of GATA2 deficiency. METHODS: Single-center, retrospective review of 157 patients with GATA2 deficiency. Disease course, laboratory results, and imaging findings were extracted. In-person rheumatological assessments were performed on selected, available patients. A literature search of four databases was conducted to identify additional cases. RESULTS: Rheumatological findings were identified in 28 patients, out of 157 cases reviewed (17.8%). Twenty-two of those patients (78.6%) reported symptom onset prior to or in conjunction with the molecular diagnosis of GATA2 deficiency. Notable rheumatological manifestations included: piezogenic pedal papules (PPP), joint hyperextensibility, early onset osteoarthritis, ankylosing spondylitis, and seronegative erosive rheumatoid arthritis. In peripheral blood of patients with rheumatological manifestations and GATA2 deficiency, CD4+ CD3+ helper T cells and naïve CD3+ CD4+ CD62L+ CD45RA+ helper T cell subpopulation fractions were significantly lower, while CD8+ cytotoxic T cell fractions were significantly higher, compared to those without rheumatological manifestations and with GATA2 deficiency. No changes in CD19, CD3, or NK populations were observed. CONCLUSION: GATA2 deficiency is associated with a broad spectrum of rheumatological disease manifestations. Low total helper T lymphocyte proportions and low naïve helper T cell proportions are associated with those most at risk of overt rheumatological manifestations. Further, PPP and joint hyperextensibility may explain some of the nonimmunologically-mediated joint problems encountered in patients with GATA2 deficiency. This catalogue suggests that rheumatological manifestations and immune dysregulation are relatively common in GATA2 deficiency.

Privacy Concerns About Personal Health Information and Fear of Unintended Use of Biospecimens Impact Donations by African American Patients.

Biospecimen donation is essential for studies of cancer prevention, early detection, and treatment. Donations from minority groups, for whom the cancer burden is high, are infrequent and inadequate for research purposes. The obstacles to donation of biospecimens by African Americans and other minority groups must be identified. Patients aged 18-85 years were surveyed based on the clinic visited (group A: GI/primary care and group B: oncology with confirmed cancer diagnosis) and analyzed as separate groups. The validated biobanking attitudes and knowledge survey (BANKS) as well as pancreatic cancer questions were used. In group A, 278/292 surveys were completed (5/6 patients participated). In group B, 54/59 surveys were completed (4/5 patients participated). There were low mean scores on the BANKS knowledge sections, specifically in regard to specimen ownership and the separation of research and medical records. Also, two major concerns limited donation: (1) fear that personal, medical, and family medical information may be stolen from the biobank; and (2) mistrust that biospecimens could be used for unintended purposes. Low knowledge about biospecimen acquisition, added to mistrust, warrant community-based, and patient education in an effort to improve attitudes, increase participation, and regain healthy therapeutic alliances.

Quantitative Proteomics Using Formalin-fixed, Paraffin-embedded Biopsy Tissues in Inflammatory Disease.

BACKGROUND: Investigations in human disease pathogenesis have been hampered due to paucity of access to fresh-frozen tissues (FFT) for use in global, data-driven methodologies. As an alternative, formalin-fixed, paraffin-embedded (FFPE) tissues are readily available in pathology banks. However, the use of formalin for fixation can lead to the loss of proteins that appear during inflammation, thus introducing an inherent sample bias. To address this, we compared FF and FFPE tissue proteomics to determine whether FFPE-tissue can be used effectively in inflammatory diseases. METHODS: Adjacent kidney slices from lupus nephritic mice were processed as FFPE or FFTs. Their tissue lysates were run together using proteomics workflow involving filter-aided sample preparation, in-solution dimethyl isotope labeling, StageTip fractionation, and nano-LC MS/MS through an Orbitrap XL MS. RESULTS: We report a >97% concordance in protein identification between adjacent FFPE and FFTs in murine lupus nephritic kidneys. Specifically, proteins representing pathways, namely, 'systemic lupus erythematosus', 'interferon-α', 'TGF-ß', and 'extracellular matrix', were reproducibly quantified between FFPE and FFTs. However, 12%-29% proteins were quantified differently in FFPE compared to FFTs, but the differences were consistent across experiments. In particular, certain proteins represented in pathways, including 'inflammatory response' and 'innate immune system' were quantified less in FFPE than in FFTs. In a pilot study of human FFPE tissues, we identified proteins relevant to pathogenesis in lupus nephritic kidney biopsies compared to control kidneys. CONCLUSION: This is the first report of lupus nephritis kidney proteomics using FFPE tissue. We concluded that archived FFPE tissues can be reliably used for proteomic analyses in inflammatory diseases, with a caveat that certain proteins related to immunity and inflammation may be quantified less in FFPE than in FFTs.

Identifying predictive features of Clostridium difficile infection recurrence before, during, and after primary antibiotic treatment.

BACKGROUND: Colonization by the pathogen Clostridium difficile often occurs in the background of a disrupted microbial community. Identifying specific organisms conferring resistance to invasion by C. difficile is desirable because diagnostic and therapeutic strategies based on the human microbiota have the potential to provide more precision to the management and treatment of Clostridium difficile infection (CDI) and its recurrence. METHODS: We conducted a longitudinal study of adult patients diagnosed with their first CDI. We investigated the dynamics of the gut microbiota during antibiotic treatment, and we used microbial or demographic features at the time of diagnosis, or after treatment, to predict CDI recurrence. To check the validity of the predictions, a meta-analysis using a previously published dataset was performed. RESULTS: We observed that patients' microbiota "before" antibiotic treatment was predictive of disease relapse, but surprisingly, post-antibiotic microbial community is indistinguishable between patients that recur or not. At the individual OTU level, we identified Veillonella dispar as a candidate organism for preventing CDI recurrence; however, we did not detect a corresponding signal in the conducted meta-analysis. CONCLUSION: Although in our patient population, a candidate organism was identified for negatively predicting CDI recurrence, results suggest the need for larger cohort studies that include patients with diverse demographic characteristics to generalize species that robustly confer colonization resistance against C. difficile and accurately predict disease relapse.

Evidence for oxidative stress in the developing cerebellum of the rat after chronic mild carbon monoxide exposure (0.0025% in air).

BACKGROUND: The present study was designed to test the hypothesis that chronic very mild prenatal carbon monoxide (CO) exposure (25 parts per million) subverts the normal development of the rat cerebellar cortex. Studies at this chronic low CO exposure over the earliest periods of mammalian development have not been performed to date. Pregnant rats were exposed chronically to CO from gestational day E5 to E20. In the postnatal period, rat pups were grouped as follows: Group A: prenatal exposure to CO only; group B: prenatal exposure to CO then exposed to CO from postnatal day 5 (P5) to P20; group C: postnatal exposure only, from P5 to P20, and group D, controls (air without CO). At P20, immunocytochemical analyses of oxidative stress markers, and structural and functional proteins were assessed in the cerebellar cortex of the four groups. Quantitative real time PCR assays were performed for inducible (iNOS), neuronal (nNOS), and endothelial (eNOS) nitric oxide synthases. RESULTS: Superoxide dismutase-1 (SOD1), SOD2, and hemeoxygenase-1 (HO-1) immunoreactivity increased in cells of the cerebellar cortex of CO-exposed pups. INOS and nitrotyrosine immunoreactivity also increased in blood vessels and Purkinje cells (PCs) of pups from group-A, B and C. By contrast, nNOS immunoreactivity decreased in PCs from group-B. Endothelial NOS immunoreactivity showed no changes in any CO-exposed group. The mRNA levels for iNOS were significantly up-regulated in the cerebellum of rats from group B; however, mRNA levels for nNOS and eNOS remained relatively unchanged in groups A, B and C. Ferritin-H immunoreactivity increased in group-B. Immunocytochemistry for neurofilaments (structural protein), synapsin-1 (functional protein), and glutamic acid decarboxylase (the enzyme responsible for the synthesis of the inhibitory neurotransmitter GABA), were decreased in groups A and B. Immunoreactivity for two calcium binding proteins, parvalbumin and calbindin, remained unchanged. The immunoreactivity of the astrocytic marker GFAP increased after prenatal exposure. CONCLUSION: We conclude that exogenously supplied CO during the prenatal period promotes oxidative stress as indicated by the up-regulation of SOD-1, SOD-2, HO-1, Ferritin-H, and iNOS with increased nitrotyrosine in the rat cerebella suggesting that deleterious and protective mechanisms were activated. These changes correlate with reductions of proteins important to cerebellar function: pre-synaptic terminals proteins (synapsin-1), proteins for the maintenance of neuronal size, shape and axonal quality (neurofilaments) and protein involved in GABAergic neurotransmission (GAD). Increased GFAP immunoreactivity after prenatal CO-exposure suggests a glial mediated response to the constant presence of CO. There were differential responses to prenatal vs. postnatal CO exposure: Prenatal exposure seems to be more damaging; a feature exemplified by the persistence of markers indicating oxidative stress in pups at P20, following prenatal only CO-exposure. The continuation of this cellular environment up to day 20 after CO exposure suggests the condition is chronic. Postnatal exposure without prenatal exposure shows the least impact, whereas prenatal followed by postnatal exposure exhibits the most pronounced outcome among the groups.