TAFRO syndrome is associated with anti-SSA/Ro60 antibodies, in contrast to idiopathic castleman disease.

TAFRO syndrome is an acute systemic inflammatory disease characterized by thrombocytopenia, anasarca, fever, reticulin fibrosis/renal dysfunction, and organomegaly. There have been increasing reports that TAFRO is a disease distinct from idiopathic multicentric Castleman disease and that TAFRO patients may be positive for anti-SSA antibodies. To assess anti-SSA antibody positivity and the clinical characteristics of the two diseases, we retrospectively compared 7 TAFRO and 10 iMCD patients in our hospital. The mean age of onset of TAFRO and iMCD was 48.0 (interquartile range [IQR], 41-53) and 45.0 (IQR, 35-53) years, respectively. The TAFRO and iMCD groups had 6 (86%) and 4 (40%) male patients, respectively, and the following pretreatment laboratory values: platelet count, 3.8 (IQR, 2.2-6.4) and 35.5 (IQR, 22.2-42.8) × 104/µL, respectively; C-reactive protein, 10.2 (IQR, 6.8-21.4) and 9.5 (IQR, 6.2-13.6) mg/dL, respectively; IgG, 1431 (IQR, 1112-1815) and 4725 (IQR, 3755-5121) mg/dL, respectively. RNA immunoprecipitation (5 cases for anti-SSA) or protein array (5 cases for anti-SSA/Ro60) detected anti-SSA antibodies in six (86%) TAFRO patients but not in iMCD patients; it did not detect anti-SSB antibodies in any of the patients. None of the patients were diagnosed with Sjögren syndrome. All iMCD patients treated with tocilizumab (TCZ) responded well. Meanwhile, two of six TAFRO patients treated with TCZ showed inadequate responses; thus, both patients were switched to rituximab, following which they achieved remission. TAFRO and iMCD have different clinical features. TAFRO may be categorized as a severe phenotype of the anti-SSA antibody syndrome.

Pathogenicity of IgG-Fc desialylation and its association with Th17 cells in an animal model of systemic lupus erythematosus.

OBJECTIVES: Decreased sialylation of IgG-Fc glycans has been reported in autoimmune diseases, but its role in systemic lupus erythematosus (SLE) is not fully understood. In this study, we examined the pathogenicity of IgG desialylation and its association with Th17 in SLE using an animal model. METHODS: B6SKG mice, which develop lupus-like systemic autoimmunity due to the ZAP70 mutation, were used to investigate the pathogenicity of IgG desialylation. The proportion of sialylated IgG was compared between B6SKG and wild-type mice with or without ß-glucan treatment-induced Th17 expansion. Anti-interleukin (IL)-23 and anti-IL-17 antibodies were used to examine the role of Th17 cells in IgG glycosylation. Activation-induced cytidine deaminase-specific St6gal1 conditionally knockout (cKO) mice were generated to examine the direct effect of IgG desialylation. RESULTS: The proportions of sialylated IgG were similar between B6SKG and wild-type mice in the steady state. However, IgG desialylation was observed after ß-glucan-induced Th17 expansion, and nephropathy also worsened in B6SKG mice. Anti-IL-23/17 treatment suppressed IgG desialylation and nephropathy. Glomerular atrophy was observed in the cKO mice, suggesting that IgG desialylation is directly involved in disease exacerbation. CONCLUSIONS: IgG desialylation contributes to the progression of nephropathy, which is ameliorated by blocking IL-17A or IL-23 in an SLE mouse model.

Enteric Toll-like receptor 7 stimulation causes acute exacerbation in lupus-susceptible mice.

Autoimmune diseases are often accompanied by acute exacerbation. However, the mechanism underlying systemic lupus erythematosus (SLE) flares remains unclear. We investigated whether short-term enteric Toll-like receptor 7 (TLR7) stimulation can exacerbate SLE using B6SKG mice, which spontaneously develop SLE due to a mutation in the zeta‒chain‒associated protein kinase 70 (Zap70) gene. Imiquimod (IMQ) or phosphate-buffered saline (PBS) were orally administered on B6WT and B6SKG mice every other day for 2 weeks. SLE exacerbation was assessed via fluorescent immunohistochemical staining of glomeruli for IgG and C3, hematoxylin and eosin staining of kidneys, and enzyme-linked immunosorbent assay for antinuclear antibody (ANA). Flow cytometry was used to evaluate germinal center B cells (GCBs), plasma cells, follicular helper T cells (Tfhs), regulatory T cells (Tregs), effector T cells (Th1s and Th17s), plasmacytoid dendritic cells (pDCs), conventional dendritic cells (cDCs), and macrophages (Mφs) in spleens. Oral administration of IMQ every other day for 2 weeks resulted in exacerbation of splenomegaly, increased IgG and C3 deposition in glomeruli, and increased ANA production in the B6SKG IMQ (SKG-IMQ) group compared to the B6SKG PBS (SKG-PBS) group; the percentages of GCBs, plasma cells, Tfhs, Th1s, pDCs, and Mφs were also increased in the SKG-IMQ group. Splenomegaly, IgG, and C3 deposition in glomeruli, and the percentages of GCBs, plasma cells, Tfhs, and Th1s were enhanced in SKG-IMQ mice compared with B6SKG mice topically treated with IMQ (SKG-ear-IMQ). Oral TLR7 stimulation in a Zap70 genetic mutation background can cause acute exacerbations of SLE. Key Points • The mechanism of SLE flares is not well understood. • We have created a model that causes short-term SLE exacerbations in mice with a genetic background. • IMQ administered orally causes more SLE in mice than transdermally.

Oral dextran sulfate sodium administration induces peripheral spondyloarthritis features in SKG mice accompanied by intestinal bacterial translocation and systemic Th1 and Th17 cell activation.

BACKGROUND: Spondyloarthritis (SpA) is an autoimmune and autoinflammatory musculoskeletal disease characterised by systemic enthesitis. Recent research has focused on subclinical inflammatory bowel disease (IBD) in SpA pathogenesis. SKG mice, harbouring the Zap70 W163C mutation, increase autoreactive Th17 cells intrinsically, and in a conventional environment, they exhibit spontaneous arthritis with fungal factors. Under SPF conditions, they show SpA features, including enteritis, after peritoneal injection of ß-1,3-glucan. This study aimed to clarify whether oral dextran sulfate sodium (DSS) administration, utilised in IBD model mice, can provoke SpA features in SKG mice under SPF conditions, focusing on the relationship between gut microorganisms and SpA pathogenesis. METHODS: BALB/c and SKG mice were administered oral DSS, and their body weights, arthritis, and enthesitis scores were recorded. In another cohort, antibiotics (meropenem and vancomycin) or an anti-fungal agent (amphotericin B) was administered orally before DSS administration. The splenic Th1 and Th17 cell populations were examined before and after DSS administration using flow cytometry. Furthermore, the amount of circulating bacterial DNA in whole blood was measured by absolute quantitative polymerase chain reaction (qPCR), and the number and characteristics of bacterial species corresponding to these circulating DNA were analysed by next-generation sequencing (NGS). RESULTS: Ankle enthesitis as a peripheral SpA feature was elicited in half of DSS-administered SKG mice, and none of the BALB/c mice. Pre-administration of antibiotics suppressed enthesitis, whilst an anti-fungal agent could not. Th1 and Th17 cell levels in the spleen increased after DSS administration, and this was suppressed by pre-administration of antibiotics. SKG mice have a larger amount of bacterial DNA in whole blood than BALB/c mice before and 1 day after the initiation of DSS administration. The number of bacterial species in whole blood increased after DSS administration in BALB/c and SKG mice. Some genera and species significantly specific to the DSS-treated SKG mouse group were also detected. CONCLUSION: Oral DSS administration alone elicited peripheral enthesitis in SKG mice with bacterial translocation accompanied by increased splenic Th1 and Th17 cell levels. Pre-administration of antibiotics ameliorated these DSS-induced SpA features. These findings suggest that intestinal bacterial leakage plays a pivotal role in SpA pathogenesis.

Feasibility of patient-oriented ultrasound joint selection: Cross-sectional observational study on rheumatoid arthritis.

Objective: Ultrasonography (US) is a useful tool for evaluating the activity of rheumatoid arthritis (RA) patients. As the systemic evaluation of many joints is time-consuming, a method to evaluate this activity with a smaller number of joints is needed. The aim of this study was to clarify whether the number of joints assessed may be reduced using patient-oriented joint selection.Methods: A total of 492 RA patients were recruited at Kyoto University Hospital. Bilateral metacarpophalangeal (MCP), (proximal) interphalangeal (PIP/IP), and wrist joints were evaluated by US. Gray scale and power Doppler imaging findings were scored by a 0-3 semi-quantitative method. Clinical assessments were performed by physicians who were blind to US results, and a questionnaire on subjective symptoms was collected from each patient.Results: The correlation between the US score of all 22 joints (US22) and patient-oriented painful joints (PtUS) or physician-oriented tender and/or swollen joints were moderate (Spearman's ρ = 0.435) and weak (ρ = 0.383), respectively. These correlations were weaker than that between the total US score of 5 preselected joints (unilateral 2MCP, 3MCP, 2PIP, 3PIP, and the wrist) and US22 (ρ = 0.813). However, when focusing on patients whose painful joints were 5 and more, the correlation between PtUS and US22 was markedly stronger (ρ = 0.757).Conclusion: Patient-oriented joint selection reflected actual joint inflammation to some extent. However, excessive reductions in the number of joints assessed need to be avoided even if patients do not have arthralgia because of the potential for underestimations.

Nutritional status is associated with the return home in a long-term care health facility.

Background: The purpose of this study was to determine the association between nutritional status and the return home of older people living in a long-term care health facility (LCHF). Methods: A nested case control study was performed in 116 people ≥65 years of age in a single LCHF. Nutritional status was assessed using the Mini Nutritional Assessment Short Form (MNA-SF) and activities of daily living by the Functional Independence Measure (FIM). The return home, duration of rehabilitation, and the family wanting the patient to return home were obtained from clinical records. Multivariate logistic regression analysis was used to assess whether malnutrition had independent effects on the return home. Results: The participants included 36 males and 80 females with a mean age of 82 years. Thirty-seven people returned home while 79 did not. The MNA-SF showed that 80 subjects were malnourished. Sixty-six of the participants received rehabilitation for longer than 1 hour per week, while 50 received rehabilitation for <1 hour. The proportion of subjects with malnutrition who returned home was significantly lower (P = .003) than in participants who did not return home. Multivariate logistic regression analysis showed that malnutrition (adjusted odds ratio [AOR], 0.23; 95% confidence interval [CI], 0.08-0.65; P = .006), total FIM score (AOR, 1.03; 95% CI, 1.01-1.06; P = .012), and the family wanting the patient to return home (AOR, 9.46; 95% CI, 3.19-28.12; P < .001) were independently associated with the return home. Conclusions: Nutritional status is associated with the return home in older people living in LCHF.

Characterizing the functions of Ty1 Gag and the Gag-derived restriction factor p22/p18.

The long terminal repeat (LTR) and non-LTR retrotransposons comprise approximately half of the human genome, and we are only beginning to understand their influence on genome function and evolution. The LTR retrotransposon Ty1 is the most abundant mobile genetic element in the S. cerevisiae reference genome. Ty1 replicates via an RNA intermediate and shares several important structural and functional characteristics with retroviruses. However, unlike retroviruses Ty1 retrotransposition is not infectious. Retrotransposons integrations can cause mutations and genome instability. Despite the fact that S. cerevisiae lacks eukaryotic defense mechanisms such as RNAi, they maintain a relatively low copy number of the Ty1 retrotransposon in their genomes. A novel restriction factor derived from the C-terminal half of Gag (p22/p18) and encoded by internally initiated transcript inhibits retrotransposition in a dose-dependent manner. Therefore, Ty1 evolved a specific GAG organization and expression strategy to produce products both essential and antagonistic for retrotransposon movement. In this commentary we discuss our recent research aimed at defining steps of Ty1 replication influenced by p22/p18 with particular emphasis on the nucleic acid chaperone functions carried out by Gag and the restriction factor.

A self-encoded capsid derivative restricts Ty1 retrotransposition in Saccharomyces.

Retrotransposons and retroviral insertions have molded the genomes of many eukaryotes. Since retroelements transpose via an RNA intermediate, the additive nature of the replication cycle can result in massive increases in copy number if left unchecked. Host organisms have countered with several defense systems, including domestication of retroelement genes that now act as restriction factors to minimize propagation. We discovered a novel truncated form of the Saccharomyces Ty1 retrotransposon capsid protein, dubbed p22 that inhibits virus-like particle (VLP) assembly and function. The p22 restriction factor expands the repertoire of defense proteins targeting the capsid and highlights a novel host-parasite strategy. Instead of inhibiting all transposition by domesticating the restriction gene as a distinct locus, Ty1 and budding yeast may have coevolved a relationship that allows high levels of transposition when Ty1 copy numbers are low and progressively less transposition as copy numbers rise. Here, we offer a perspective on p22 restriction, including its mode of expression, effect on VLP functions, interactions with its target, properties as a nucleic acid chaperone, similarities to other restriction factors, and future directions.

Ty1 retrovirus-like element Gag contains overlapping restriction factor and nucleic acid chaperone functions.

Ty1 Gag comprises the capsid of virus-like particles and provides nucleic acid chaperone (NAC) functions during retrotransposition in budding yeast. A subgenomic Ty1 mRNA encodes a truncated Gag protein (p22) that is cleaved by Ty1 protease to form p18. p22/p18 strongly inhibits transposition and can be considered an element-encoded restriction factor. Here, we show that only p22 and its short derivatives restrict Ty1 mobility whereas other regions of GAG inhibit mobility weakly if at all. Mutational analyses suggest that p22/p18 is synthesized from either of two closely spaced AUG codons. Interestingly, AUG1p18 and AUG2p18 proteins display different properties, even though both contain a region crucial for RNA binding and NAC activity. AUG1p18 shows highly reduced NAC activity but specific binding to Ty1 RNA, whereas AUG2p18 shows the converse behavior. p22/p18 affects RNA encapsidation and a mutant derivative defective for RNA binding inhibits the RNA chaperone activity of the C-terminal region (CTR) of Gag-p45. Moreover, affinity pulldowns show that p18 and the CTR interact. These results support the idea that one aspect of Ty1 restriction involves inhibition of Gag-p45 NAC functions by p22/p18-Gag interactions.

A trans-dominant form of Gag restricts Ty1 retrotransposition and mediates copy number control.

UNLABELLED: Saccharomyces cerevisiae and Saccharomyces paradoxus lack the conserved RNA interference pathway and utilize a novel form of copy number control (CNC) to inhibit Ty1 retrotransposition. Although noncoding transcripts have been implicated in CNC, here we present evidence that a truncated form of the Gag capsid protein (p22) or its processed form (p18) is necessary and sufficient for CNC and likely encoded by Ty1 internal transcripts. Coexpression of p22/p18 and Ty1 decreases mobility more than 30,000-fold. p22/p18 cofractionates with Ty1 virus-like particles (VLPs) and affects VLP yield, protein composition, and morphology. Although p22/p18 and Gag colocalize in the cytoplasm, p22/p18 disrupts sites used for VLP assembly. Glutathione S-transferase (GST) affinity pulldowns also suggest that p18 and Gag interact. Therefore, this intrinsic Gag-like restriction factor confers CNC by interfering with VLP assembly and function and expands the strategies used to limit retroelement propagation. IMPORTANCE: Retrotransposons dominate the chromosomal landscape in many eukaryotes, can cause mutations by insertion or genome rearrangement, and are evolutionarily related to retroviruses such as HIV. Thus, understanding factors that limit transposition and retroviral replication is fundamentally important. The present work describes a retrotransposon-encoded restriction protein derived from the capsid gene of the yeast Ty1 element that disrupts virus-like particle assembly in a dose-dependent manner. This form of copy number control acts as a molecular rheostat, allowing high levels of retrotransposition when few Ty1 elements are present and inhibiting transposition as copy number increases. Thus, yeast and Ty1 have coevolved a form of copy number control that is beneficial to both "host and parasite." To our knowledge, this is the first Gag-like retrotransposon restriction factor described in the literature and expands the ways in which restriction proteins modulate retroelement replication.

Fragile DNA motifs trigger mutagenesis at distant chromosomal loci in saccharomyces cerevisiae.

DNA sequences capable of adopting non-canonical secondary structures have been associated with gross-chromosomal rearrangements in humans and model organisms. Previously, we have shown that long inverted repeats that form hairpin and cruciform structures and triplex-forming GAA/TTC repeats induce the formation of double-strand breaks which trigger genome instability in yeast. In this study, we demonstrate that breakage at both inverted repeats and GAA/TTC repeats is augmented by defects in DNA replication. Increased fragility is associated with increased mutation levels in the reporter genes located as far as 8 kb from both sides of the repeats. The increase in mutations was dependent on the presence of inverted or GAA/TTC repeats and activity of the translesion polymerase Polζ. Mutagenesis induced by inverted repeats also required Sae2 which opens hairpin-capped breaks and initiates end resection. The amount of breakage at the repeats is an important determinant of mutations as a perfect palindromic sequence with inherently increased fragility was also found to elevate mutation rates even in replication-proficient strains. We hypothesize that the underlying mechanism for mutagenesis induced by fragile motifs involves the formation of long single-stranded regions in the broken chromosome, invasion of the undamaged sister chromatid for repair, and faulty DNA synthesis employing Polζ. These data demonstrate that repeat-mediated breaks pose a dual threat to eukaryotic genome integrity by inducing chromosomal aberrations as well as mutations in flanking genes.

Genome-wide screen identifies pathways that govern GAA/TTC repeat fragility and expansions in dividing and nondividing yeast cells.

Triplex structure-forming GAA/TTC repeats pose a dual threat to the eukaryotic genome integrity. Their potential to expand can lead to gene inactivation, the cause of Friedreich's ataxia disease in humans. In model systems, long GAA/TTC tracts also act as chromosomal fragile sites that can trigger gross chromosomal rearrangements. The mechanisms that regulate the metabolism of GAA/TTC repeats are poorly understood. We have developed an experimental system in the yeast Saccharomyces cerevisiae that allows us to systematically identify genes crucial for maintaining the repeat stability. Two major groups of mutants defective in DNA replication or transcription initiation are found to be prone to fragility and large-scale expansions. We demonstrate that problems imposed by the repeats during DNA replication in actively dividing cells and during transcription initiation in nondividing cells can culminate in genome instability. We propose that similar mechanisms can mediate detrimental metabolism of GAA/TTC tracts in human cells.

An experimental system for the study of mutations in the HMR locus of Saccharomyces cerevisiae: the insertion of Ty into HMRa vs. the conversion of HMRa to HMRalpha.

A cross between a sir4-11 strain (sir4-11 HMLalpha MATalpha HMRa, non-mating type) and an a-mating strain (SIR(+) HMLalpha MATa HMRa) of Saccharomyces cerevisiae forms diploid clones at a frequency of 5 x 10(-6), but the obtained diploid clones often (>70%) have altered forms of the HMRa-containing restriction fragment, designated @ HMRa'. We previously found that some HMRa's are associated with the conversion of HMRa to HMRalpha. In this report, we present evidence that another @ HMRa' associates with the insertion of Ty into Ya of HMR. We also found that the sir4-11 strain increased mating frequency by UV irradiation to a level of 9 x 10(-4), and that generation of HMRa' was completely prevented by disruption of RAD52 of the sir4-11 strain. Hence, we conclude that the mutations that cause generation of HMRa' occur in the sir4-11 strain prior to mating. Due to these mutations, the sir4-11 strain converts to alpha-mating type and readily mates with the a-mating strain. We discuss the usefulness of the sir4-11 strain for the study of mutations in the HMR locus of S. cerevisiae.

Mating-induced mating-type cassette conversion in Saccharomyces cerevisiae.

We have previously reported that the HMRa-bearing restriction fragment of a rho degrees sir4-11 strain (HMLalpha-MATalpha-HMRa), which acts as an alpha-mater because of being rho degrees , changes its electrophoretic mobility when the strain mates with a certain group of a-mating strains (HMLalpha-MATa-HMRa). In this study, we found that the sir4-11 strain being rho degrees was not essential for this phenomenon and also that the altered form of the fragment contained HMRalpha in place of HMRa. Furthermore, we observed conversion of HMLa to HMLalpha in the cross in which a sir4-11 HMLa-MATalpha-HMRalpha strain was mated with a representative of the above-mentioned a-mating strain. In addition, when this a-mating strain was mated with a SIR(+) HMLalpha-MATa-HMRalpha strain, the resultant diploid was found to be HMLalpha/HMLalpha MATa/MATalphaHMRa/HMRalpha, indicating that conversion of MATa to MATalpha had taken place in the course of mating. From all these observations, we conclude that there is a group of S. cerevisiae strains that carries factor(s) that induces conversion of a mating-type cassette of the mating partner to alpha mating-type cassette and that this mating type cassette conversion takes place in all three mating type loci, HML, MAT and HMR, if the loci are in the non-silenced condition.