To investigate predictors of hypogammaglobulinemia (HGG) and severe infection event (SIE) in patients with autoimmune disease (AID) receiving rituximab (RTX) therapy. This was a retrospective study conducted in a tertiary medical center in China. Predictors of HGG or SIE were assessed using Cox analysis. Restricted cubic spline (RCS) analysis was applied to examine the correlation between glucocorticoid (GC) maintenance dose and SIE. A total of 219 patients were included in this study, with a cumulative follow-up time of 698.28 person-years. Within the study population, 117 patients were diagnosed with connective tissue disease, 75 patients presented with ANCA-associated vasculitis, and 27 patients exhibited IgG4-related disease. HGG was reported in 63.3

ObjectiveTo develop and conduct an initial validation of the Damage Index for IgG4-related disease (IgG4-RD DI).MethodsA draft of index items for assessing organ damages in patients with IgG4-RD was generated by experts from the Chinese IgG4-RD Consortium (CIC). The preliminary DI was refined using the Delphi method, and a final version was generated by consensus. 40 IgG4-RD cases representing four types of clinical scenarios were then selected, each with two time points of assessment for at least 3 years of follow-up. 48 rheumatologists from 35 hospitals nationwide were invited to evaluate organ damage using the CIC IgG4-RD DI. The intraclass correlation coefficient (ICC) and the Kendall-W coefficient of concordance (KW) were used to assess the inter-rater reliability. The criterion validity of IgG4-RD DI was tested by calculating the sensitivity and specificity of raters.ResultsIgG4-RD DI is a cumulative index consisting of 14 domains of organ systems, including a total of 39 items. The IgG4-RD DI was capable of distinguishing stable and increased damage across the active disease subgroup and stable disease subgroup. In terms of scores at baseline and later observations by all raters, overall consistency in scores at baseline and later observations by all raters was satisfactory. ICC at the two time points was 0.69 and 0.70, and the KW was 0.74 and 0.73, respectively. In subgroup analysis, ICC and KW in all subgroups were over 0.55 and 0.61, respectively. The analysis of criterion validity showed a good performance with a sensitivity of 0.86 (95% CI 0.82 to 0.88), a specificity of 0.79 (95% CI 0.76 to 0.82) and an area under the curve of 0.88 (95% CI 0.85 to 0.91).ConclusionThe IgG4-RD DI is a useful approach to analyse disease outcomes, and it has good operability and credibility. It is anticipated that the DI will become a useful tool for therapeutic trials and studies of prognosis in patients with IgG4-RD.

OBJECTIVES:To assess the expression of age-associated B cells (ABCs), and characterise the surface markers of ABCs in patients with IgG4-related disease (IgG4-RD).METHODS:Fifty-one newly diagnosed patients with IgG4-RD, 18 IgG4-RD patients with disease remission, 34 patients with other autoimmune diseases, and 61 age- and sex-matched healthy controls (HCs) were included. Circulating ABCs, as well as surface markers were detected by flow cytometry, and tissue infiltration of ABCs were assessed by immunofluorescence (IF). The expression of ABCs in the affected organs of LatY136F knock-in (LAT) mouse models (IgG4-RD mouse model) were explored by flow cytometry and IF.RESULTS:The percentages and absolute numbers of ABCs (gated as CD21-T-bet+CD11c+) in CD19+ B cells raised remarkably in untreated IgG4-RD patients than HC, and reduced significantly after treatment. The percentage of CD27+ABCs, DN2 B cells and activated naive B cells was higher in patients with IgG4-RD than in HCs and patients with multiple autoimmune diseases, whereas the percentage was comparable with that in patients with systemic lupus erythematosus. Phenotypical analysis revealed upregulated levels of CD86, TACI, CD38, and downregulated level of CXCR3 in peripheral CD19+CD21-CD11c+ B cells of IgG4-RD patients compared with that of HC. In IgG4-RD patients, CD19+CD21- CD11c+ cells expressed higher levels of CD80, CXCR3, TACI, CD95, and BAFF-R, while lower levels of CD86, CD27, CD38, and CXCR5 compared with CD19+ CD21- CD11c- B cells. ABCs (CD11c+T-bet+ gated in B220+ cells) were increased significantly in lungs of LAT mice than that of wild type (WT) mice.CONCLUSIONS:ABCs were expanded both in the peripheral blood and affected tissues of patients with IgG4-RD as well as in the lungs of LAT mice, indicating the potential roles of ABCs in IgG4-RD pathogenesis.

Objective: To externally validate the performance of the 2019 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for IgG4-related disease (IgG4-RD) within a cohort from China and to compare the criteria with the 2020 revised comprehensive diagnostic (RCD) criteria for IgG4-RD. Methods: This study included 875 IgG4-RD and 302 non-IgG4-RD cases (213 mimickers and 89 patients with other diseases). Using expert clinical judgment as the gold standard for diagnosis of IgG4-RD, the performance (sensitivity, specificity, area under the curve (AUC) of the 2019 ACR/EULAR criteria for IgG4-RD was evaluated. We also compared it with the 2020 RCD criteria. Results: The 2019 ACR/EULAR classification criteria had a sensitivity of 76.6% (95% CI: 73.8% to 79.4%) and a specificity of 98.0% (96.0%-99.4%), an AUC of 0.873 (0.857-0.889) in the overall cohort. Those false negative cases under the 2019 ACR/EULAR classification criteria had significantly lower levels of serum IgG4, and fewer had pathological information, with a higher frequency in the involvement of those uncommon organs compared with the true positive cases. The cases judged as negative by the 2019 ACR/EULAR classification criteria yet judged as "definite" by the 2020 RCD criteria had more involvement of uncommon organs. Conclusions: The 2019 ACR/EULAR classification criteria for IgG4-RD show outstanding specificity and good sensitivity in real-world clinical practice. The 2020 RCD criteria are helpful for the diagnosis of IgG4-RD in clinical scenarios where IgG4-RD presents as involving an isolated organ, especially the unusual sites.

Objective Autoimmune comorbidities may be associated with IgG4-related disease (IgG4-RD), here we aimed to determine the correlation of autoimmune diseases (AID) family history and IgG4-RD in a Chinese cohort. Methods This retrospective cohort study identified 628 cases of IgG4-RD in Peking Union Medical College Hospital. Patients were classified into two groups, with AID family history group (AID-positive) and without AID family history group (AID-negative). We viewed the potential value of AID family history on IgG4-RD by comparing the differences between the two groups. In addition, Cox regression analysis estimated CIs and HR for IgG4-RD risk. Results 93 (14.8%) IgG4-RD patients had AID family history. Compared with AID-negative group, baseline data analysis revealed that AID-positive group patients had an earlier age of IgG4-RD onset (50.4±14.8 vs 54.2±12.6, p=0.014*), a higher percentage of antinuclear antibody (ANA) positivity (38.9% vs 22.7%, p=0.0277*) and Riedel thyroiditis (10.9% vs 2.4%, p=0.001*), were prone to comorbid with other AID (16.1% vs 6.2%, p=0.0238*). Cox analysis found that younger age (HR 0.97 (95% CI 0.94 to 0.99), p=0.0384*) and higher proportions of baseline peripheral eosinophils (HR 1.1 (95% CI 1.02 to 1.2), p=0.0199*) increased the risk of unfavourable prognosis for AID-positive IgG4-RD patients. Conclusions 14.8% of IgG4-RD patients had AID family history, with younger age of disease onset age and higher frequency of ANA positivity in AID-positive group, indicating that IgG4-RD may share genetic background with other AID.

To investigate B-cell repopulation trajectory and the associated factors in patients with autoimmune diseases (AIDs) who underwent rituximab (RTX) treatment. This is a retrospective study in a large tertiary medical center. Kaplan-Meier analysis and Cox regression were used to investigate factors associated with B-cell repopulation. Latent class trajectory modeling (LCTM) was employed to identify distinct B-cell repopulation trajectory longitudinally. A total of 224 patients were included, with a cumulative follow-up time of 193.6 person-years. Patients with antineutrophil cytoplasm antibody-associated vasculitis (AAV), connective tissue disease, and IgG4-related disease exhibited significant differences in B-cell repopulation time (p = 0.0055 by log-rank test). Multivariate Cox regression identified that higher levels of IgA (HR 1.21, 95%CI 1.01-1.45, p = 0.040) and concurrent glucocorticoid use (HR = 0.37,95%CI 0.20-0.67, p = 0.001) were associated with B-cell repopulation. The cluster showing prolonged B-cell depletion, identified by LCTM, had lower proportions of male (27% vs. 48.5%, p = 0.033), smoke history (17.6% vs. 38.7%, p = 0.025), higher proportions of AAV (44.3% vs. 15.2%, p = 0.004), RTX dose (p = 0.042), history of cyclophosphamide use (70.4% vs. 48.5%, p = 0.003), meanwhile glucocorticoid use (94.8% vs. 72.7%, p = 0.001). The trajectory of B-cell repopulation after RTX infusion in AIDs was heterogeneous. Certain factors were associated with B-cell repopulation, and a specific cluster of patients demonstrated prolonged B-cell depletion after RTX treatment.

Abstract Objective To figure out the functions of thymic stromal lymphopoietin (TSLP) in IgG4-related disease (IgG4-RD). Methods Plasma TSLP levels were tested by Elisa, and its receptors were detected by flow cytometry. Expressions of TSLP and TSLPR in involved tissues were stained by immunohistochemistry and immunofluorescence. Proliferation, apoptosis, and B subsets of TSLP stimulated-B cells were analyzed by flow cytometry. TSLP-stimulated B cells were co-cultured with CD4+ Naïve T cells. Signaling pathway was identified by RNA-sequencing and western blot. Anti-TSLP therapy was adapted in LatY136F knock-in mice (Lat, IgG4-RD mouse model). Results Plasma TSLP level was increased in IgG4-RD patients and was positively correlated with serum IgG4 level and responder index (RI). TSLPR was co-localized with CD19+ B cells in the submandibular glands (SMGs) of IgG4-RD. TSLP promoted B cell proliferation, and TSLP-activated B cells polarized CD4+ naive T cells into follicular helper T (Tfh) cells through OX40L. RNA-sequencing identified JAK-STAT signaling pathway in TSLP-activated B cells and it was verified by western blot. Anti-TSLP therapy alleviated the inflammation of lung in Lat mice. Conclusion Elevated TSLP in IgG4-RD promoted B cells proliferation and polarized Tfh cells and might be served as a potential therapeutic target.