Unveiling the intricacies of COVID-19: Autoimmunity, multi-organ manifestations and the role of autoantibodies.

COVID-19 is a severe infectious disease caused by a SARS-CoV-2 infection. It has caused a global pandemic and can lead to acute respiratory distress syndrome (ARDS). Beyond the respiratory system, the disease manifests in multiple organs, producing a spectrum of clinical symptoms. A pivotal factor in the disease's progression is autoimmunity, which intensifies its severity and contributes to multi-organ injuries. The intricate interaction between the virus' spike protein and human proteins may engender the generation of autoreactive antibodies through molecular mimicry. This can further convolute the immune response, with the potential to escalate into overt autoimmunity. There is also emerging evidence to suggest that COVID-19 vaccinations might elicit analogous autoimmune responses. Advanced technologies have pinpointed self-reactive antibodies that target diverse organs or immune-modulatory proteins. The interplay between autoantibody levels and multi-organ manifestations underscores the importance of regular monitoring of serum antibodies and proinflammatory markers. A combination of immunosuppressive treatments and antiviral therapy is crucial for managing COVID-19-associated autoimmune diseases. The review will focus on the generation of autoantibodies in the context of COVID-19 and their impact on organ health.

Clinical characteristics and prognostic value of autoantibody profile in children with monogenic lupus.

Objective: To report the frequency of selected autoantibodies and their associations with clinical features in Arab children with monogenic lupus. Methods: This study was retrospective single-center study of genetically confirmed monogenic lupus cases at childhood lupus clinic at King Faisal Specialist Hospital and Research Center, from June 1997 to July 2022. We excluded familial lupus without genetic testing and patients with insufficient data. Collected data comprised clinical and laboratory findings, including the autoantibody profile, which included the anti-double-stranded DNA (anti-dsDNA), anti-Smith, anti-Sjögren's-syndrome-related antigen A (anti-SSA), anti-Sjögren's-syndrome-related antigen B (anti-SSB), and antiphospholipid (APL) antibodies. Also, disease activity and accrual disease damage were collected at the last follow-up visit. Results: This study enrolled 27 Arab patients (14 males) with a median age of 11 years (interquartile range 8.0~16 years), with 63% having early-onset disease. The consanguinity rate and family history of lupus were high (74.1% and 55.6%, respectively). The most frequent clinical features were hematological (96.3%), fever (81.5%), mucocutaneous lesions (85.2%), and renal (66.7%). The frequency of the APL antibodies was 59.3%, anti-dsDNA was 55.6%, and anti-Smith and anti-SSA were 48.2% and 44.4%, respectively. Moreover, dsDNA antibodies were significantly associated with musculoskeletal complaints (p<0.05). Likewise, both anti-Smith and anti-SSA antibodies were linked to failure to thrive and recurrent infections in the univariate analysis (p<0.05). Conclusion: Our study reveals autoantibody frequencies and their association with clinical and prognostic in a substantial monogenic lupus cohort. Distinct clinical manifestations and prognosis association with certain autoantibodies support the idea that monogenic lupus is a distinctive form of lupus. Larger studies needed to validate these findings.

An integrative exploration of environmental stressors on the microbiome-gut-brain axis and immune mechanisms promoting neurological disorders.

The microbiome-gut-brain axis is altered by environmental stressors such as heat, diet, and pollutants as well as microbes in the air, water, and soil. These stressors might alter the host's microbiome and symbiotic relationship by modifying the microbial composition or location. Compartmentalized mutualistic microbes promote the beneficial interactions in the host leading to circulating metabolites and hormones such as insulin and leptin that affect inter-organ functions. Inflammation and oxidative stress induced by environmental stressors may alter the composition, distribution, and activities of the microbes in the microbiomes such that the resultant metabolite and hormone changes are no longer beneficial. The microbiome-gut-brain axis and immune adverse changes that may accompany environmental stressors are reviewed for effects on innate and adaptive immune cells, which may make host immunity less responsive to pathogens and more reactive to self-antigens. Cardiovascular and fluid exchanges to organs might adversely alter organ functionality. Organs, especially the brain, need a consistent supply of nutrients and clearance of debris; disruption of these exchanges by stressors, and involvement of gut microbiome are discussed regarding neural dysfunctions with Alzheimer's disease, autistic spectrum disorders, viral infections, and autoimmune diseases. The focus of this review includes the manner in which environmental stressors may disrupt gut microbiota leading to adverse immune and hormonal influences on development of neuropathology related to hyperhomocysteinemia, inflammation, and oxidative stress, and how certain therapeutics may be beneficial. Strategies are explored to lessen detrimental effects of environmental stressors on central and peripheral health navigated toward (1) understanding neurological disorders and (2) promoting environmental and public health and well-being.

Racial variability in immune responses only partially explains differential systemic sclerosis disease severity.

OBJECTIVE: To understand if autoantibodies account for racial variation in disease severity, we compared autoantibody distribution and associated phenotype between self-identified black and white systemic sclerosis (SSc) patients. METHODS: 803 black and 2178 white SSc patients had systematic testing for autoantibodies using Euroimmun (centromere (ACA), RNA-polymerase III (POLR3), Scl70, PM/Scl, NOR90, Th/To, Ku, U3RNP and Ro52) and commercial ELISA (U1RNP). In this observational study, logistic regression was performed to assess the association between self-identified race and outcomes, adjusting for autoantibodies. To estimate whether the effect of race was mediated by autoantibody status, race coefficients from multivariate models including and excluding autoantibodies were compared. RESULTS: Anti-Scl70, anti-U1RNP, anti-U3RNP, anti-Th/To, anti-Ku and anti-NOR90 were more common in the black cohort than in the white cohort, which was enriched for ACA, anti-POLR3 and anti-PM/Scl. Black individuals had a higher prevalence of severe Raynaud's, skin, lung, gastrointestinal and renal disease whereas white individuals had a higher prevalence of severe heart and muscle disease. Adjusting for autoantibodies decreased the effect of race on outcome for telangiectasias, forced vital capacity <70%, pulmonary hypertension and severe lung, heart, muscle and gastrointestinal disease by 11%-44% and increased the association between race and renal crisis and severe kidney disease by 37%-52%. CONCLUSIONS: This study is the largest systematic analysis of autoantibody responses in a geographically diverse population of black SSc patients. Black and white individuals with SSc have distinct autoantibody profiles. Autoantibodies explain only a fraction of the effect of race on clinical outcomes, suggesting other factors contribute to disparate outcomes between these groups.

Autoantibodies Neutralizing GM-CSF in HIV-Negative Colombian Patients Infected with Cryptococcus gattii and C. neoformans.

BACKGROUND: Cryptococcosis is a life-threatening disease caused by Cryptococcus neoformans or C. gattii. Neutralizing autoantibodies (auto-Abs) against granulocyte-macrophage colony-stimulating factor (GM-CSF) in otherwise healthy adults with cryptococcal meningitis have been described since 2013. We searched for neutralizing auto-Abs in sera collected from Colombian patients with non-HIV-associated cryptococcosis in a retrospective national cohort from 1997 to 2016. METHODS: We reviewed clinical and laboratory records and assessed the presence of neutralizing auto-Abs against GM-CSF in 30 HIV negative adults with cryptococcosis (13 caused by C. gattii and 17 caused by C. neoformans). RESULTS: We detected neutralizing auto-Abs against GM-CSF in the sera of 10 out of 13 (77%) patients infected with C. gattii and one out of 17 (6%) patients infected with C. neoformans. CONCLUSIONS: We report eleven Colombian patients diagnosed with cryptococcosis who had auto-Abs that neutralize GM-CSF. Among these patients, ten were infected with C. gattii and only one with C. neoformans.

Anti-factor H autoantibodies in patients with lupus nephritis.

INTRODUCTION: Lupus nephritis (LN) is a disease marked by autoantibodies against complement components. Autoantibodies against negative complement regulator factor H (anti-FH) are prevalent in aHUS, are associated with deletion of factor H-related protein 1 (FHR1) gene, and have overt functional consequences. They are also observed in C3 glomerulopathies. The frequency and relevance of anti-FH in LN are poorly studied. AIM: The aim of our investigation was to screen for the presence of anti-FH and FHR1 gene deletion in a cohort of LN patients and to evaluate their association with LN activity. METHOD: ELISA test and Western blot for detection of anti-FH and FHR1 deletion were used, respectively. Patients' clinical and laboratory parameters regarding anti-FH role were processed by statistical analysis. RESULTS: Anti-FH were found at low level in a small number of LN patients - 11.7% (7/60) and were not associated with deletion of FHR1. Anti-FH did not correlate with ANA titers, anti-dsDNA, C3/C4 hypocomplementemia, eGFR, proteinuria, or active urinary sediment in LN patients. A weak correlation was found between anti-FH and anti-C3 levels. Anti-FH were linked with endocapillary proliferation and histological activity index. Four anti-FH positive patients had severe to moderate LN as per the BILAG renal score. CONCLUSIONS: Anti-FH autoantibodies are an accessory finding in LN and are more likely to manifest during the active phase of the disease. Due to their low frequency and plasma levels, they do not seem suitable for routine laboratory investigation in patients with LN.

Outcome clusters and their stability over 1 year in patients with SLE: self-reported and performance-based cognitive function, disease activity, mood and health-related quality of life.

OBJECTIVE: To determine if self-reported fatigue, anxiety, depression, cognitive difficulties, health-related quality of life, disease activity scores and neuropsychological battery (NB) cluster into distinct groups in patients with SLE based on symptom intensity and if they change at 1-year follow-up. METHODS: This is a retrospective analysis of consecutive consenting patients, followed at a single centre. Patients completed a comprehensive NB, the Beck Anxiety Inventory, Beck Depression Inventory, Fatigue Severity Scale, Short-Form Health Survey Physical Component Summary and Mental Component Summary scores and the Perceived Deficits Questionnaire. Disease activity was assessed by Systemic Lupus Erythematosus Disease Activity Index 2000. Ward's method was used for clustering and principal component analysis was used to visualise the number of clusters. Stability at 1 year was assessed with kappa statistic. RESULTS: Among 142 patients, three clusters were found: cluster 1 had mild symptom intensity, cluster 2 had moderate symptom intensity and cluster 3 had severe symptom intensity. At 1-year follow-up, 49% of patients remained in their baseline cluster. The mild cluster had the highest stability (77% of patients stayed in the same cluster), followed by the severe cluster (51%), and moderate cluster had the lowest stability (3%). A minority of patients from mild cluster moved to severe cluster (19%). In severe cluster, a larger number moved to moderate cluster (40%) and fewer to mild cluster (9%). CONCLUSION: Three distinct clusters of symptom intensity were documented in patients with SLE in association with cognitive function. There was a lower tendency for patients in the mild and severe clusters to move but not moderate cluster over the course of a year. This may demonstrate an opportunity for intervention to have moderate cluster patients move to mild cluster instead of moving to severe cluster. Further studies are necessary to assess factors that affect movement into moderate cluster.

Severe West Nile virus and Sars-CoV-2 infections in a patient with thymoma and anti-type I IFN antibodies.

The current study aimed to investigate determinants of severity in a previously healthy patient who experienced two life-threatening infections, from West Nile Virus and SARS-CoV2. During COVID19 hospitalization he was diagnosed with a thymoma, retrospectively identified as already present at the time of WNV infection. Heterozygosity for p.Pro554Ser in the TLR3 gene, which increases susceptibility to severe COVID-19, and homozygosity for CCR5 c.554_585del, associated to severe WNV infection, were found. Neutralizing anti-IFN-α and anti-IFN-ω auto-antibodies were detected, likely induced by the underlying thymoma and increasing susceptibility to both severe COVID-19 pneumonia and West Nile encephalitis.

Correlation between neuropsychiatric systemic lupus erythematosus and immunological markers: a real-world retrospective study.

OBJECTIVES: This study aimed to investigate disparities in clinical profiles and autoantibody patterns between patients with and without neuropsychiatric systemic lupus erythematosus (NPSLE) in a cohort and to identify risk factors associated with NPSLE in the Chinese population. METHODS: SLE patients were retrospectively reviewed from two tertiary hospitals. The relationships between NPSLE and immunological biomarkers were explored. RESULTS: Among the 945 SLE patients, 75 (7.94%) were diagnosed with NPSLE. The most prevalent NP manifestations involved cognitive disorder (30.67%), headache (26.67%), seizure disorder (26.67%), and psychosis (26.67%).We observed significant associations between psychosis and anti-ß2GPI antibodies (F = 6.092, p = 0.015), polyneuropathy and anti-Scl70 antibodies (F = 20.161, p < 0.001), demyelinating syndrome and anti-cardiolipin antibodies (F = 6.637, p = 0.011), myasthenia gravis and anti-RNP (F = 5.864, p = 0.017), and anti-Smith antibodies (F = 5.096, p = 0.026). Multivariate logistics analysis showed that anti-prothrombin (aPT) IgM antibodies (OR = 10.985, CI 1.279-94.343, p = 0.029), age (OR = 1.169, CI 1.032-1.325, p = 0.014), and serum creatinine (SCr) (OR = 1.014, CI 1.003-1.025, p = 0.009) were independent risk factors of NPSLE, while anti-Sjogren syndrome antigen B (SSB) antibodies (OR 0.023, CI 0.002-0.622, p = 0.023) and high complement C3 (OR = 0.001, CI 0-0.045, p < 0.001) indicated reduced risk of NPSLE. CONCLUSION: Various neuropsychiatric manifestations in SLE were found to be correlated with specific autoantibodies. Independent risk factors for NPSLE included aPT IgM antibodies, age, and elevated serum creatinine, while the absence of anti-SSB antibodies and low complement C3 levels were associated with increased risk. KEY POINTS: •Significant associations were found between specific autoantibodies and neuropsychiatric symptoms, shedding light on potential biomarkers for predicting and understanding NPSLE. •The study identifies independent risk factors for NPSLE in the Chinese population, including the presence of anti-prothrombin IgM antibodies, older age, elevated serum creatinine, and lower complement C3 levels.

Human determinants of age-dependent patterns of death from infection.

Regardless of microbial virulence (i.e., the global infection-fatality ratio), age generally drives the prevalence of death from infection in unvaccinated humans. Four mortality patterns are recognized: the common U- and L-shaped curves of endemic infections and the unique W- and J-shaped curves of pandemic infections. We suggest that these patterns result from different sets of human genetic and immunological determinants. In this model, it is the interplay between (1) monogenic genotypes affecting immunity to primary infection that preferentially manifest early in life and related genotypes or their phenocopies, including auto-antibodies, which manifest later in life and (2) the occurrence and persistence of adaptive, acquired immunity to primary or cross-reactive infections, which shapes the age-dependent pattern of human deaths from infection.

Emerging treatment landscape for Guillain-Barré Syndrome (GBS): what's new?

INTRODUCTION: Guillain-Barré syndrome (GBS) is a monophasic immune neuropathic disorder characterized by acute paralysis. A significant portion of patients are left with residual deficits, which presents a considerable global healthcare challenge. The precise mechanisms underlying GBS pathogenesis are not fully elucidated. Recent studies have focused on postinfectious molecular mimicry and identified involvement of IgG autoantibodies and innate immune effectors in GBS. Intravenous immunoglobulins (IVIg) and plasma exchange (PE) are two established evidence-based immunomodulatory treatments for GBS, but a significant proportion of GBS patients fails to respond adequately to either therapy. This emphasizes an urgent need for novel and more potent treatments. AREAS COVERED: We discuss novel immunomodulatory therapies presently at different phases of preclinical and clinical investigation. Some drugs in development target pathophysiologic mechanisms such as IgG autoantibody catabolism and complement activation, which are relevant to GBS. EXPERT OPINION: There is an unmet need for more effective immune therapies for GBS. New immunomodulatory therapies under development may provide more potent options for GBS patients who do not respond to IVIg or PE. Future directions may include incorporating neuroprotective interventions based on evolving understanding of mechanisms underlying nerve injury and axonal degeneration.

Sialylation status in placentas from anti-Ro/SSA- and anti-La/SSB-positive pregnant women.

Women affected by different autoimmune diseases and displaying positivity for anti-Ro/SSA and anti-La/SSB autoantibodies are at high risk of adverse pregnancies in which placental dysfunction seems to play a determinant role. Sialylation is known to have important implications in the maintenance of the normal morpho-functional features of the placenta. Hence, the present study aimed to investigate possible changes in the distribution and content of sialic acids (Sias) with different glycosidic linkages (i.e., α2,3 and α2,6 Galactose- or N-acetyl-Galactosamine-linked Sias, and polysialic acid) in placentas from anti-Ro/SSA- and anti-La/SSB-positive pregnant women with autoimmune diseases by using lectin histochemistry and polysialic acid immunohistochemistry. Our findings revealed lower levels of α2,3-linked Sias in the trophoblast and basement membrane and/or basal plasma membrane of the pathological cases respect to control placentas. Some vessels of the pathological cases displayed α2,3-linked Sias. α2,6-linked Sias positivity was detected in the trophoblast and in some vessels of the pathological cases, while in control samples it was present only in the vessels. Lower levels of polysialic acid were observed in the trophoblast of pathological cases compared to controls. Collectively, our findings suggest that multiple changes in the sialylation status of placenta might affect placental morpho-functional features in anti-Ro/SSA- and anti-La/SSB-positive pregnancies.

Prevalence of antiphospholipid autoantibodies associated with biologics treatment for psoriasis.

Psoriasis is a chronic inflammatory disease that sometimes necessitates therapeutic intervention with biologics. Autoantibody production during treatment with tumor necrosis factor (TNF) inhibitors is a recognized phenomenon, however, the production of autoantibodies associated with antiphospholipid syndrome (APS) has not been comprehensively evaluated in patients with psoriasis. This study was conducted to assess the prevalence of APS-associated autoantibodies in patients with psoriasis treated with different biologics and to investigate the potential associations between autoantibody production and clinical or serological parameters. Patients with psoriasis undergoing biologics treatments were enrolled in this study, and were categorized based on the type of biologics administered, TNF, interleukin (IL)-17, or IL-23 inhibitors. Clinical and serological data were collected and analyzed in conjunction with data on APS autoantibodies. TNF inhibitors were associated with a higher frequency of APS autoantibodies compared to IL-17 and IL-23 inhibitors. Notably, the presence of APS autoantibodies correlated with concurrent arthritis and higher disease severity at treatment initiation in patients treated with TNF inhibitors. Elevated Psoriasis Area and Severity Index scores and anti-nuclear antibody titers higher than × 320 were predictors of APS autoantibody production. Despite the higher autoantibody rates, clinical symptoms of APS were absent in these patients. This study provides the first comprehensive evidence of an increased frequency of APS autoantibodies associated with TNF inhibitor treatment in patients with psoriasis. The observed association between APS autoantibody positivity and TNF inhibitor treatment or clinical parameters suggests a potential immunomodulatory interplay between autoimmunity and inflammation in the pathogenesis of psoriasis.

Association of autoantibodies with the IFN signature and NETosis in patients with systemic lupus erythematosus.

Objective: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a variety of disease symptoms and an unpredictable clinical course. To improve treatment outcome, stratification based on immunological manifestations commonly seen in patients with SLE such as autoantibodies, type I interferon (IFN) signature and neutrophil extracellular trap (NET) release may help. It is assumed that there is an association between these immunological phenomena, since NET release induces IFN production and IFN induces autoantibody formation via B-cell activation. Here we studied the association between autoantibodies, the IFN signature, NET release, and clinical manifestations in patients with SLE. Methods: We performed principal component analysis (PCA) and hierarchical clustering of 57 SLE-related autoantibodies in 25 patients with SLE. We correlated each autoantibody to the IFN signature and NET inducing capacity. Results: We observed two distinct clusters: one cluster contained mostly patients with a high IFN signature. Patients in this cluster often present with cutaneous lupus, and have higher anti-dsDNA concentrations. Another cluster contained a mix of patients with a high and low IFN signature. Patients with high and low NET inducing capacity were equally distributed between the clusters. Variance between the clusters is mainly driven by antibodies against histones, RibP2, RibP0, EphB2, RibP1, PCNA, dsDNA, and nucleosome. In addition, we found a trend towards increased concentrations of autoantibodies against EphB2, RibP1, and RNP70 in patients with an IFN signature. We found a negative correlation of NET inducing capacity with anti-FcER (r = -0.530; p = 0.007) and anti-PmScl100 (r = -0.445; p = 0.03). Conclusion: We identified a subgroup of patients with an IFN signature that express increased concentrations of antibodies against DNA and RNA-binding proteins, which can be useful for further patient stratification and a more targeted therapy. We did not find positive associations between autoantibodies and NET inducing capacity. Our study further strengthens the evidence of a correlation between RNA-binding autoantibodies and the IFN signature.

Autoantibodies in COVID-19 survivors with post-COVID symptoms: a systematic review.

Objective: The long-lasting persistence of autoantibodies stands as one of the hypotheses explaining the multisystemic manifestations seen in individuals with post-COVID-19 condition. The current review offers restricted insights into the persistence of autoantibodies in plasma/serum in people with post-COVID symptoms. Methods: PubMed/MEDLINE, CINAHL, EMBASE, and Web of Science databases, as well as on medRxiv and bioRxiv preprint servers were searched up to January 5th, 2024. Papers investigating the presence of autoantibodies in plasma/serum samples in people with post-COVID symptoms were included. The Newcastle-Ottawa Scale (NOS) was used to assess methodological quality. Results: From 162 identified records, five articles met all inclusion criteria; four studies included infected controls with no post-COVID symptoms whereas all five studies included non-infected controls (410 COVID-19 survivors with post-COVID symptoms, 223 COVID-19 survivors with no post-COVID symptoms as controls and 266 non-infected healthy controls). Four studies concluded that the presence of autoantibodies had a potential (but small) role in post-COVID-19 condition whereas one study concluded that autoantibodies were not associated. Quality assessment showed all studies had high methodological quality. Conclusion: Although evidence suggests that persistent autoantibodies can be associated with post-COVID symptoms, the clinical relevance of their presence seems modest at this stage. Current results highlight further research to clarify the role of autoantibodies in the development of post-COVID symptoms, guiding the development of tailored diagnostic and treatment approaches to enhance patient outcomes. Systematic review registration: https://osf.io/vqz28.

Alteration of reactive oxygen species master transcription factor Nrf2 in keratinocytes exposed to monoclonal pathogenic antibody AK23 against desmoglein-3 in pemphigus vulgaris.

Keratinocytes in mucosal and skin tissues maintain tissue integrity via desmosomes and desmoglein-3 (Dsg3). Pemphigus Vulgaris (PV) is a life-threatening autoimmune blistering disease characterized by autoantibodies against Dsg3, disrupting desmosomes. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates oxidative stress responses crucial for skin tissue protection. Although the pathogenesis of PV is known, the detailed molecular events remain unclear. This study investigates changes in Nrf2 expression in keratinocytes following pathogenic anti-Dsg3 antibody AK23 exposure, using dose- and time-dependent studies employing immunofluorescence analysis. N/TERT keratinocytes were cultured in keratinocytes serum-free medium and treated with AK23 at varying doses (5 µg/mL,40µg/mL,75µg/mL) and durations (2, 6, 24 h). Immunofluorescence staining was performed to assess the expression of Nrf2 and Dsg3. All fluorescent images were analyzed using ImageJ software. A dose-dependent increase in Dsg3 was noted following AK23 treatment, while Nrf2 expression and subcellular localization varied. Time-course analyses showed decreased Nrf2 at 24 h and increased Dsg3 levels. Early time-point (2 and 6 h) variations were evident in Nrf2 levels. This study highlights the impact of AK23 on Nrf2 expression, potentially disrupting Nrf2-mediated cytoprotection and implicating oxidative stress (ROS generation) in PV pathogenesis. Further investigation is necessary to validate the findings.

Anti-CRMP2 antibody induces anxiety-like behavior and increases pyramidal neuron excitability in mice.

BACKGROUND: We have previously identified auto-antibody (Ab) to collapsin response mediator protein 2 (CRMP2) in patients with encephalitis. The present study aims to evaluate the pathogenic effects of anti-CRMP2 Ab. METHODS: Recombinant CRMP2 protein was injected subcutaneously into mice to establish an active immune mouse model with anti-CRMP2 Ab. Behavioral assessments, histopathological staining, and electrophysiological testing were performed to identify any pathogenic changes. RESULTS: The mice exhibited signs of impaired motor coordination four weeks post-immunization of CRMP2 protein. Moreover, CRMP2 immunized mice for eight weeks showed anxiety-like behaviors indicating by tests of open field and the elevated plus maze. After incubating the CA1 region of hippocampal brain section with the sera from CRMP2 immunized mice, the whole-cell path-clamp recordings showed increased excitability of pyramidal neurons. However, no obvious inflammation and infiltration of immune cells were observed by histopathological analysis. Western blot showed that the phosphorylation levels of CRMP2-Thr514 and -Ser522 were not affected. CONCLUSION: In an active immunization model with CRMP2 protein, impaired coordination and anxiety-like behaviors were observed. Also, anti-CRMP2 Abs containing sera heightened the excitability of hippocampal pyramidal neurons in vitro, which imply the pathogenic effects of anti-CRMP2 Ab.

[Application value of anti-carbamylated protein antibody in the diagnosis of rheumatoid arthritis].

OBJECTIVE: To investigate the expression level and application value of anti-carbamylated protein (CarP) antibody in rheumatoid arthritis (RA). METHODS: Demographic data and laboratory test results of RA patients, non-RA patients and healthy controls in the physical examination center were reviewed from December 2018 to June 2019 in the Rheumatology and Immunology Department of the People' s Hospital of Xinjiang Uygur Autonomous Region. The serum concentrations of anti-CarP antibodies in all the subjects were measured by ELISA and statistically analyzed. RESULTS: A total of 259 subjects were included in this study, including 158 in the RA group (45 serum-negative RA patients), 59 in the non-RA group and 42 in the healthy control group. The concentration of anti-CarP antibody in RA group [8.31 (5.22, 15.26) U/mL] was higher than that in non-RA group [4.50 (3.35, 5.89) U/mL] and healthy control group [3.46 (2.76, 4.92) U/mL]. The concentration of anti-CarP antibody in non-RA group was not significantly different from that in healthy control group (P=0.10). Receiver operating characteristic (ROC) curve analysis showed that the sensitivity of anti-CarP antibody in the diagnosis of RA was 58.2%, and the specificity was 93.1%. The sensitivity of the combined detection of anti-CarP antibody, anti-cyclic peptide containing citrulline (CCP) antibody and rheumatoid factor (RF) was 82.3%, and the specificity was 96.5%. The positive rate of anti-CarP antibody in serum-negative RA patients was 44.4% (20/45). Univariate Logisitic regression analysis showed that age, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), RF, glucose-6-phosphate isomerase (GPI), anti-CCP antibody and anti-CarP antibody were risk factors for RA. Multivariate Logisitic regression analysis showed that anti-CCP antibody and anti-CarP antibody were independent risk factors for RA. Spearman correlation analysis showed that there was no significant correlation between anti-CarP antibody and swollen joint count (SJC), tenderness joints count (TJC), ESR, disease activity score for 28 joints (DAS28), clinical disease activity index (CDAI), simplified disease activity index (SDAI). The concentration of anti-CarP antibody in RA with bone erosion (n=88) was higher than that in RA without bone erosion (n=70), and there was significant difference between the two groups (P < 0.05). CONCLUSIONS: Anti-CarP antibody is an effective serological marker for the diagnosis of RA. The combined detection of RF, anti-CCP antibody and anti-CarP antibody can improve its diagnostic value, and anti-CarP antibody may be an effective assistant diagnostic tool for serum negative RA. The high serum concentration of anti-CarP antibody in patients with RA may indicate an increased risk of bone erosion and should be treated early, but further cohort studies are needed for follow-up observation.