Besides anti-citrullinated protein antibodies (ACPA), rheumatoid arthritis patients (RA) often display autoantibody reactivities against other post-translationally modified (PTM) proteins, more ...specifically carbamylated and acetylated proteins. Immunizing mice with one particular PTM results in an anti-modified protein antibody (AMPA) response recognizing different PTM-antigens. Furthermore, human AMPA, isolated based on their reactivity to one PTM, cross-react with other PTMs. However, it is unclear whether the AMPA-reactivity profile is "fixed" in time or whether consecutive exposure to different PTMs can shape the evolving AMPA response towards a particular PTM.
Longitudinally collected serum samples of 8 human individuals at risk of RA and 5 with early RA were tested with ELISA, and titers were analyzed to investigate the evolution of the AMPA responses over time. Mice (13 per immunization group in total) were immunized with acetylated (or carbamylated) protein (ovalbumin) twice or cross-immunized with an acetylated and then a carbamylated protein (or vice versa) and their serum was analyzed for AMPA responses.
Human data illustrated dynamic changes in AMPA-reactivity profiles in both individuals at risk of RA and in early RA patients. Mice immunized with either solely acetylated or carbamylated ovalbumin (AcOVA or CaOVA) developed reactivity against both acetylated and carbamylated antigens. Irrespective of the PTM-antigen used for the first immunization, a booster immunization with an antigen bearing the other PTM resulted in increased titers to the second/booster PTM. Furthermore, cross-immunization skewed the overall AMPA-response profile towards a relatively higher reactivity against the "booster" PTM.
The relationship between different reactivities within the AMPA response is dynamic. The initial exposure to a PTM-antigen induces cross-reactive responses that can be boosted by an antigen bearing this or other PTMs, indicating the formation of cross-reactive immunological memory. Upon subsequent exposure to an antigen bearing another type of PTM, the overall reactivity pattern can be skewed towards better recognition of the later encountered PTM. These data might explain temporal differences in the AMPA-response profile and point to the possibility that the PTM responsible for the initiation of the AMPA response may differ from the PTM predominantly recognized later in time.
Background
Polymyositis/dermatomyositis (PM/DM) is an autoimmune disease that is sometimes complicated with rapidly progressive interstitial lung disease (RPILD). However, serum and lung biomarkers ...that can predict RPILD development remain unclear.
Objectives
To determine potential serum and lung biomarkers that can predict RPILD development in patients with PM/DM‐ILD.
Methods
In total, 49 patients with PM/DM‐ILD were enrolled. We measured the serum levels of 41 cytokines/chemokines, ferritin and anti‐MDA5 antibody, compared them between the RPILD (n = 23) and non‐RPILD (n = 26) groups, and ranked them by their importance through random forest analysis. To distinguish the two groups, we determined biomarker combinations by logistic regression analysis. We also measured the bronchoalveolar lavage fluid (BALF) levels of 41 cytokines/chemokines. Using immunohistochemistry, we examined IL‐15 expression in lung tissues. The IL‐15 production was also investigated using A549 and BEAS‐2B cells.
Results
The RPILD group had significantly higher IL‐15, IL‐1RA, IL‐6, CXCL10, VCAM‐1, anti‐MDA5 antibody and ferritin serum levels than the non‐RPILD group, but it had a significantly low CCL22 level. Meanwhile, anti‐MDA5 antibody, IL‐15, CXCL8, CCL22, IL‐1RA and ferritin were the best combination to distinguish the two groups. IL‐15 and CCL22 were also predictive marker for RPILD development in anti‐MDA5 antibody‐positive patients. Additionally, the RPILD group had significantly high IL‐15 levels in BALF. The lung tissues expressed IL‐15, which increased after cytokine stimulation in the A549 cells.
Conclusion
This study identified a combination of biomarkers predicting PM/DM‐RPILD progression, and IL‐15 is an important cytokine for predicting RPILD development and reflecting ILD severity.
Summary
Primary biliary cholangitis (PBC) is characterized by the presence of serum anti‐mitochondrial autoantibodies (AMAs). To date, four antigens among the 2‐oxo‐acid dehydrogenase complex family, ...which commonly have lipoyl domains as an epitope, have been identified as AMA‐corresponding antigens (AMA‐antigens). It has recently been reported that AMAs react more strongly with certain chemically modified mimics than with the native lipoyl domains in AMA‐antigens. Moreover, high concentrations of circulating immune complexes (ICs) in PBC patients have been reported. However, the existence of ICs formed by AMAs and their antigens has not been reported to date. We hypothesized that AMAs and their antigens formed ICs in PBC sera, and analyzed sera of PBC and four autoimmune diseases (Sjögren's syndrome, systemic lupus erythematosus, systemic scleroderma, and rheumatoid arthritis) using immune complexome analysis, in which ICs are separated from serum and are identified by nano‐liquid chromatography‐tandem mass spectrometry. To correctly assign MS/MS spectra to peptide sequences, we used a protein‐search algorithm that including lipoylation and certain xenobiotic modifications. We found three AMA‐antigens, the E2 subunit of the pyruvate dehydrogenase complex (PDC‐E2), the E2 subunit of the 2‐oxo‐glutarate dehydrogenase complex (OGDC‐E2) and dihydrolipoamide dehydrogenase binding protein (E3BP), by detecting peptides containing lipoylation and xenobiotic modifications from PBC sera. Although the lipoylated sites of these peptides were different from the well‐known sites, abnormal lipoylation and xenobiotic modification may lead to production of AMAs and the formation ICs. Further investigation of the lipoylated sites, xenobiotic modifications, and IC formation will lead to deepen our understanding of PBC pathogenesis.
Primary biliary cholangitis (PBC) is characterized by the presence of serum anti‐mitochondrial autoantibodies (AMAs) against the 2‐oxo‐acid dehydrogenase complex family; however, the immune complexes (ICs) formed by AMAs and the antigens has not been reported to date and their in vivo antigenicity is not fully clear. Immune complexome analysis identified three AMA‐antigens to be incorporated into ICs from PBC sera, the E2 subunit of the pyruvate dehydrogenase complex (PDC‐E2), the E2 subunit of the 2‐oxo‐glutarate dehydrogenase complex (OGDC‐E2), and dihydrolipoamide dehydrogenase binding protein (E3BP), by detecting peptides containing lipoylation or xenobiotic modifications. The lipoylated sites of these peptides were different from the well‐known sites; therefore, abnormal lipoylation and xenobiotic modification may lead to production of AMAs and the formation ICs
We previously designed a modified channelrhodopsin-1 (mVChR1) protein chimera with a broader action than that of Chlamydomonas channelrhodopsin-2 and reported that its transduction into retinal ...ganglion cells can restore visual function in genetically blind, dystrophic Royal College of Surgeons (RCS) rats, with photostimuli ranging from 486 to 640 nm. In the current study, we sought to investigate the safety and influence of mVChR1 transgene expression. Adeno-associated virus type 2 encoding mVChR1 was administered by intravitreous injection into dystrophic RCS rats. Reverse-transcription PCR was used to monitor virus and transgene dissemination and the results demonstrated that their expression was restricted specifically within the eye tissues, and not in non-target organs. Moreover, examination of the blood, plasma and serum revealed that no excess immunoreactivity was present, as determined using standard clinical hematological parameters. Serum antibodies targeting the recombinant adeno-associated virus (rAAV) capsid increased after the injection; however, no increase in mVChR1 antibody was detected during the observation period. In addition, retinal histological examination showed no signs of inflammation in rAAV-injected rats. In conclusion, our results demonstrate that mVChR1 can be exogenously expressed without harmful immunological reactions in vivo. These findings will aid in studies of AAV gene transfer to restore vision in late-stage retinitis pigmentosa.
This study investigated the effectiveness of treatment with Janus kinase (JAK) inhibitors in rheumatoid arthritis (RA) assessed by ultrasonography (US) activity, and the influence of patient ...characteristics and previous treatments.
This prospective study assessed 60 treatment initiations among 53 Japanese patients diagnosed with RA who underwent treatment with JAK inhibitors during June 2013 to February 2020. Of the 53 patients, seven patients were enrolled in duplicate because they were treated with two different JAK inhibitors at different periods. For each case, the improvement rate on the power Doppler (PD) score was assessed at 6 month follow-up. Median improvement rate of PD score was used to classify cases as either US responders or non-responders, and patient characteristics were compared between the two groups.
All indicators of clinical disease activity and US activity showed a significant improvement at 3 months compared with baseline. Although the JAK inhibitor-cycler group and the interleukin-6 (IL-6) inhibitor inadequate response (IR) group tended to show a later improvement for US activity, all indicators of clinical disease activity and US activity showed a significant improvement at 6 months compared with baseline for both groups. Multivariate analysis showed that concomitant methotrexate use and an IR to the previous biologic or targeted-synthetic disease-modifying anti-rheumatic drug (b/tsDMARD) treatment were independently and significantly associated with US responders.
Use of a JAK inhibitor in combination with methotrexate and an absence of IR to any previous b/tsDMARDs demonstrated superior effectiveness for patients with RA.
Objectives: Using multicentre ultrasound (US) cohort data among patients with rheumatoid arthritis (RA), we aimed to identify baseline factors that permit differentiation between two patient cohorts ...achieving US remission and clinical remission, and to determine the factors contributing to the discrepancy.
Method: We reviewed 248 Japanese patients diagnosed with RA who underwent treatment with biological disease-modifying anti-rheumatic drugs at 13 centres. We performed US assessments of the synovia of 22 joints. We assessed the percentages of patients with clinical remission and US remission, defined as total power Doppler scores of 0 at 12 months.
Results: The 87 patients who achieved US remission were divided into a group that achieved both clinical and US remission (n = 53) and a group that achieved US remission only (n = 34). Baseline factors that were significantly and independently associated with clinical remission at 12 months among patients who also achieved US remission included short disease duration, the presence of concomitant methotrexate use, and low patient global assessment score (p < 0.05, p < 0.05, and p < 0.005, respectively).
Conclusions: RA patients with baseline high patient global assessment scores and long disease duration at baseline were unlikely to achieve clinical remission even after achieving US remission. Objective joint assessments using US provide additional information of potential importance for the management of RA.
: We investigated whether the positivity of anti-citrullinated peptide antibody (ACPA) is associated with cigarette-smoking status and human T-cell leukaemia virus type 1 (HTLV-1) infection in a ...general population in Nagasaki, Japan, which is an ageing and HTLV-1-endemic area.
: Baseline data from community-dwelling people in the Nagasaki Islands Study (NaIS) were included in this cross-sectional analysis. ACPA and HTLV-1 were measured in 3887 subjects without a history of treatment for rheumatoid arthritis. A logistic regression analysis was performed to assess the relationship between ACPA positivity and candidates of correlation with ACPA, i.e. the cigarette-smoking status quantified by Brinkman's index (BI) and HTLV-1 positivity.
: Fifty-one subjects (1.3%) showed ACPA positivity, and 650 subjects (16.6%) were HTLV-1 carriers. In an age- and gender-adjusted logistic regression analysis, the BI odds ratio (OR) 1.09, 95% confidence interval (CI)1.02-1.14, p = 0.0031 and a BI value > 500 (OR 3.92, 95% CI 1.72-9.22, p = 0.0014) were each significantly associated with ACPA positivity. HTLV-1 positivity did not show any association with ACPA positivity.
: A significant effect of cigarette-smoking status on ACPA production was revealed, whereas HTLV-1 positivity was not associated with ACPA production in this general population.
Objectives: This study compared indocyanine green (ICG)-enhanced fluorescence optical imaging (FOI) and musculoskeletal ultrasound (MSUS), and explored the significance of the FOI findings based on ...the association between the FOI and MSUS findings and serum biomarkers in patients with rheumatoid arthritis (RA). The study also explored the association between the FOI findings and patients' joint destruction at the joint-area level.
Method: We enrolled 50 consecutive patients with active RA from among the patients hospitalized from May 2014 to March 2016 at Nagasaki University Hospital, Japan. FOI images were acquired with the Xiralite
®
fluorescence imaging system and compared with the patients' clinical examination results and MSUS findings. On the same day, the patients' clinical disease activity and levels of serum biomarkers (including vascular endothelial growth factor) were obtained.
Results: Although the FOI detected synovitis with high sensitivity, the frequency of positive findings and the diagnostic performance with MSUS as the reference standard for FOI differed considerably among the phases of FOI as well as among the affected joint regions. The FOI scores were positively correlated with clinical disease activity, MSUS scores, and serum biomarkers. The severity of FOI-proven synovitis was associated with the presence of MSUS-proven bone erosion.
Conclusion: FOI is effective for detecting joint inflammation in RA patients, with high accuracy. The severity of the FOI score was closely associated with the joint destruction at the joint-area level. However, the significance of positive FOI findings differed depending on not only the phase of FOI but also the affected joint regions.
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