IgG Deposits Research Articles

Mechanism Study on the Regulation of Th1/Th2 in the Treatment of Idiopathic Membranous Nephropathy by Shengyang Yiwei Decoction.

Shengyang Yiwei Decoction showed efficacy in idiopathic membranous nephropathy treatment, and this study aimed to assess the underlying molecular mechanisms. Rats with passive Heymann nephritis were divided into the model group, the Shengyang Yiwei Decoction group, the JAK2 inhibitor group, and the STAT3 inhibitor group. Healthy rats served as the normal control. 24-hour urinary protein excretion, IgG deposition, renal histopathology, the expression levels of synaptopodin, nephrin, podocalyxin, interferon-γ, interleukin- 4, T-box expressed in T cells, GATA binding protein-3, and relevant pathway proteins were measured. Within the model group, a notable elevation in the 24-h urinary protein level was observed, accompanied by evident IgG deposition, increased glomerular volume, eosinophilic deposits, diminished expression of podocyte marker proteins, and a discernible imbalance in Th1/Th2 cellular immunity. Conversely, in Shengyang Yiwei Decoction and both inhibitor groups, enhancements were observed across the aforementioned indexes. Shengyang Yiwei Decoction may reduce glomerular podocyte injury through the suppression of the JAK2/STAT3 signaling pathway and modulation of the Th1/Th2 immune balance.

Effectiveness of a Novel PLA2R1 Knock-In Rat Model in Repairing Renal Function Damage.

Phospholipase A2 receptor 1 (PLA2R1) exists in many animals and plays an important role in membranous nephropathy. In this study, we aimed to evaluate a PLA2R1 knock-in rat model with repaired kidney function to study the molecular mechanisms of membranous nephropathy. We constructed the PLA2R1 knockout [PLA2R1(-)] model and PLA2R1 knock in [PLA2R1(+)] model in rats. Consistent complement C3 and IgA expression was confirmed through colocalization studies. Urinary biochemical indicators were performed using Automatic Biochemistry Analyzer. The complement C3, IgG, and Nephrin were detected by immunofluorescence assay. The expression levels of complement C3, IgA, and PLA2R1 were detected by western blot. The differential expression proteins (DEPs) between control and PLA2R1(+) models were detected by liquid chromatography with tandem mass spectrometry. The PLA2R1(-) model showed proteinuria, complement C3 aggregation, and IgA and IgG deposition in the glomerulus. Comparing with the PLA2R1(-) model, the PLA2R1(+) model, the deposition of complement C3 and IgA in the glomerulus did not completely disappear, and IgG expression weakened. Moreover, the absolute value of urinary protein was much lower in the PLA2R1(+) model than in the PLA2R1(-) model, and some of the humanized PLA2R1 gene fragments repaired some of the kidney functions. Humanized PLA2R1-insertion in rats can repair part of the renal function and reduce proteinuria, which will help in studying the molecular mechanisms of membranous nephropathy, as well as the entire membranous nephropathy-related system and complement activation signaling pathway.

Pemphigoide of Pregnancy: Case Report and Review of the Literature

Pemphigoid of pregnancy (PG) is a rare autoimmune bullous dermatosis, affecting 1 in 20000 to 50000 pregnant women. PG is linked to anti-BP180 autoantibodies whose synthesis follows a breakdown in mother-fetal immunological tolerance. Bullae formation results from a complex mechanism involving TH2 lymphocytes, cytokines and polynuclear cells. PG manifests itself as a pruritic erythematopapular rash of varying extent, progressing to the inconstant but suggestive appearance of vesicles and bullae. The disease progresses to gradual recovery after delivery, sometimes after a post-partum flare-up. Recurrence during subsequent pregnancies is frequent. Relapses can also be triggered by estrogen-progestogen contraception. Diagnosis is confirmed by direct immunofluorescence, which shows C3 +/- IgG deposits along the basement membrane. The BP180-NC16A ELISA technique is highly sensitive for the detection of circulating antibodies. Fetal prognosis is good, but early onset in the 1st or 2nd trimester of pregnancy of pregnancy and the presence of bullae are risk factors for prematurity or hypotrophy. Very rarely, the newborn may present transient bullae. Several publications show that very strong dermocorticoids are effective and can be used as first-line treatment for moderate PG. We report the case of a patient admitted to a maternity hospital emergency department, with a pregnancy of 37 weeks' gestation and a non-reassuring fetal condition presenting as pemphigoid of pregnancy (PG).

C3 deficiency promotes pulmonary inflammation in AT1R-induced mouse model for systemic sclerosis.

Autoantibody-mediated complement activation plays an essential role in a variety of autoimmune disorders. However, the role of complement in systemic sclerosis (SSc) remains largely unknown. In this study, we aimed to determine the role of complement C3 in the development of a recently described SSc mouse model based on autoimmunity to angiotensin II receptor type 1 (AT1R). Mice were immunized with cell membrane extract isolated from Chinese hamster ovary (CHO) cells overexpressing AT1R or non-transfected CHO cells as a control. Peripheral blood, dorsal skin and the lung were then collected to evlauate disease characteristics. Apoptotic cells in the lung of mice were detected using the DeadEnd™ Fluorometric TUNEL System. Our results showed that experimental SSc in this model was featured by the deposition of IgG, but not of complement C3, in the lung. After immunization with AT1R, C3-deficient mice developed more severe pulmonary inflammations than wild type controls, whereas skin inflammation and fibrosis were not different as well as the anti-AT1R ab levels. Further, C3-deficient mice showed an increased rate of pulmonary cell apoptosis as compared to controls. The apoptosis rate correlated with the corresponding degree of lung inflammation. Taken together, our findings suggest an anti-apoptotic and anti-inflammatory role of complement C3 in pulmonary autoimmune inflammation.

Clinical Characteristics, Comorbidities, and Treatment in Patients with Pemphigus-A Single-Center Retrospective Study.

Pemphigus comprises a diverse group of disorders within the autoimmune bullous dermatoses (AIBDs) spectrum. Among these, pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are the most commonly encountered variants. Despite its rarity, this condition can pose a life-threatening risk. We aimed to assess clinical characteristics, comorbidities, medication, as well as the treatment of various types of pemphigus in pemphigus patients. We gathered data from 69 patients treated in the Department of Dermatology in the years 2016-2023. The investigation included sex, age at diagnosis, type of pemphigus, comorbidities and medications, presence of neoplasms and treatment of pemphigus, as well as enzyme-linked immunosorbent assay (ELISA) and direct immunofluorescence (DIF) results. The data were statistically analyzed with the p-value set at 0.05. The study group comprised 69 patients, including 41 women and 28 men. The mean age at diagnosis was 56.89 years +/- 15.42 years. A total of 79.31% of the patients were diagnosed with PV and the following 26.09% with PF. The most common comorbidities were arterial hypertension, hypercholesterolemia, and diabetes mellitus. The dominant treatment regimen was the systemic use of glucocorticosteroids (GCSs; 90% and 94% of PV and PF patients, respectively). More than half of the patients received at least one GCS-sparing treatment, including dapsone and rituximab. We observed a significantly frequent presence of IgG deposits in DIF in patients with PF (p = 0.0217) and a subsequent correlation between the concurrent presence of IgG deposits in DIF and anti-DSG1 antibodies in ELISA testing (p = 0.0469). The combination of IgG, IgG1, IgG4, and C3 deposits was more often existent in PF patients (p = 0.0054) and the combination of IgG4 and C3 deposits in PV patients (p = 0.0339). We also found a positive correlation between the level of anti-DSG1 antibodies and the age at diagnosis (p = 0.0298). Patients with pemphigus are very often diagnosed with significant comorbidities and take diverse medication, which shows that the treatment of pemphigus should follow a multidisciplinary approach. Accurate analysis of the clinical condition of the patients, as well as the results of the ELISA panel or DIF, is crucial for a successful diagnostic and therapeutic process.

Role of LIPIN 1 in regulating metabolic homeostasis in the retinal pigment epithelium.

Dysregulated lipid metabolism, characterized by the accumulation of lipid deposits on Bruch's membrane and in drusen, is considered a key pathogenic event in age-related macular degeneration (AMD). The imbalance of lipid production, usage, and transport in local tissues, particularly in the retinal pigment epithelium (RPE), is increasingly recognized as crucial in AMD development. However, the molecular mechanisms governing lipid metabolism in the RPE remain elusive. LIPIN1, a multifunctional protein acting as both a modulator of transcription factors and a phosphatidate phosphatase (PAP1), is known to play important regulatory roles in lipid metabolism and related biological functions, such as inflammatory responses. While deficits in LIPIN1 have been linked to multiple diseases, its specific roles in the retina and RPE remain unclear. In this study, we investigated LIPIN1 in RPE integrity and function using a tissue-specific knockout animal model. The clinical and histological examinations revealed age-dependent degeneration in the RPE and the retina, along with impaired lipid metabolism. Bulk RNA sequencing indicated a disturbance in lipid metabolic pathways. Moreover, these animals exhibited inflammatory markers reminiscent of human AMD features, including deposition of IgG and C3d on Bruch's membrane. Collectively, our findings indicate that LIPIN1 is a critical component of the complex regulatory network of lipid homeostasis in the RPE. Disruption of LIPIN1-mediated regulation impaired lipid balance and contributed to AMD-related pathogenic changes.

GS-4997 halts the progression of tubulointerstitial injury inlupus nephritis.

Tubulointerstitial injury has been increasingly recognized as an important component in lupus nephritis (LN) pathology over the last decades. However, current clinical treatment options for this process remain limited. In this study, we aimed to investigate the potential benefits of GS-4997, a selective inhibitor of ASK1, in tubulointerstitial injury of LN. Female MRL/lpr mice were used as a classical lupus-prone murine model. Development of nephritis was assessed by monitoring of proteinuria, renal function, and histologic analysis. GS-4997 (50 mg/kg) or vehicle were treated orally. Invitro study, human kidney-2 (HK-2) cells were stimulated with 1 μg/mL lipopolysaccharide (LPS) to mimic the response of renal tubular epithelial cells undergoing inflammatory responses during LN. GS-4997 could inhibit the activation of the ASK1 in renal tubulointerstitium in MRL/lpr mice and LPS-induced HK-2 cells. GS-4997 treatment improved renal function, proteinuria, and attenuated tubular injury, renal interstitial fibrosis, and inflammation both invivo and invitro. Additionally, we found that in MRL/lpr mice, GS-4997 reduced deposition of IgG and C3 in the kidneys, antibody levels in the serum, splenic enlargement, and inflammatory cell infiltration in the spleen. Mechanistically, GS-4997 inhibited the activation of downstream signaling molecules, p38 and JNK, in the ASK1 signaling pathway. Pharmacological inhibition of ASK1 may prevent the progression of tubulointerstitial injury via inhibiting the ASK1/MAPK pathway in LN. Therefore, our findings demonstrate the potential use of GS-4997 for LN treatment.

Effectiveness of a Novel PLA2R1 Knock-in Middle Age Rat Model in Repairing Renal Function Damage.

Phospholipase A2 receptor 1 (PLA2R1) exists important role in membranous nephropathy. In this study, we evaluate a PLA2R1 in a middle-aged rat model of renal function repair to further investigate the molecular mechanisms of membranous nephropathy. We analyzed the PLA2R1 knockout (KO) model and PLA2R1 knock in (KI) model in rats, extending the time to 85 weeks of age. Urinary biochemical indicators were detected using a fully automated biochemical analyzer. The complement C3, IgG, and Nephrin were detected using the immunofluorescence method. Western blot was used to detect the expression levels of complement C3, IgA and PLA2R1 in middle-aged models. The KO model continues to display glomerular proteinuria, complement C3 aggregation, and IgA and IgG deposition. Comparing with the KO model, the deposition of complement C3 and IgA in the glomerulus of the KI chimeric model still exists and IgG expression weakened. Inserting humanized PLA2R1 into rats can continuously repair partial renal function and reduce proteinuria, which will help investigate the pathogenesis of membranous nephropathy and complement activation signaling pathways.

A Case of Concurrent Anti-Glomerular Basement Membrane Antibody Disease and Immunoglobulin A Nephropathy

Anti-glomerular basement membrane (GBM) antibody disease is a rare autoimmune disorder characterized by autoantibodies directed against antigens within the GBM, primarily affecting the kidneys and lungs. This severe form of glomerulonephritis has an incidence of less than two cases per million individuals with crescentic glomerulonephritis. The coexistence of immunoglobulin A (IgA) nephropathy and anti-GBM disease is rare. Here, we present a case of concurrent anti-GBM antibody disease and IgA nephropathy. A 49-year-old male presented with fever, azotemia, proteinuria, and hematuria. Biopsy of the kidney revealed crescentic glomerulonephritis with linear IgG deposition along the GBM and IgA deposition in the mesangium. Elevated serum levels of anti-GBM antibody (311 U/mL) confirmed the diagnosis of concurrent anti-GBM antibody disease and IgA nephropathy. Despite treatment with methylprednisolone, cyclophosphamide, and plasma exchange, renal function deteriorated, necessitating hemodialysis.

ACK1 and BRK non-receptor tyrosine kinase deficiencies are associated with familial systemic lupus and involved in efferocytosis.

Systemic lupus erythematosus (SLE) is an autoimmune disease, the pathophysiology and genetic basis of which are incompletely understood. Using a forward genetic screen in multiplex families with SLE, we identified an association between SLE and compound heterozygous deleterious variants in the non-receptor tyrosine kinases (NRTKs) ACK1 and BRK. Experimental blockade of ACK1 or BRK increased circulating autoantibodies in vivo in mice and exacerbated glomerular IgG deposits in an SLE mouse model. Mechanistically, NRTKs regulate activation, migration, and proliferation of immune cells. We found that the patients' ACK1 and BRK variants impair efferocytosis, the MERTK-mediated anti-inflammatory response to apoptotic cells, in human induced pluripotent stem cell (hiPSC)-derived macrophages, which may contribute to SLE pathogenesis. Overall, our data suggest that ACK1 and BRK deficiencies are associated with human SLE and impair efferocytosis in macrophages.

A Comparative Study of Direct Immunofluorescence Patterns in Linear IgA Bullous Dermatosis Versus Dermatitis Herpetiformis.

Dermatitis herpetiformis (DH) is typically characterized by granular IgA deposition in the papillary dermis on direct immunofluorescence (DIF), and linear IgA bullous dermatosis (LABD) is characterized by linear deposition of IgA along the basement membrane. Other DIF findings in both conditions may include IgG, IgM, and C3 deposition in various patterns. In cases where immunofluorescence findings are unclear, such as continuous but somewhat granular IgA deposition along the dermal-epidermal junction, additional DIF patterns may be helpful in the diagnostic process. Forty-five cases of digitized images of LABD and 48 digitized images of DH cases were analyzed. The data regarding the positivity and patterns of immunoglobulins were documented and analyzed. None of the LABD cases had a picket fence pattern, while 47.9% (n = 23) of the DH cases had the pattern. Elevated levels of IgG and IgM were found in LABD compared with DH. In DH, higher IgM and kappa light chain levels were observed in the deposited particles compared with those in LABD. The "picket fence pattern" is highly specific for DH (Specificity 100%) but less sensitive (Sensitivity 47.9%). It may be helpful to differentiate between DH and LABD for a more accurate diagnosis.

METTL3 facilitates kidney injury through promoting IRF4-mediated plasma cell infiltration via an m6A-dependent manner in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown cause. N6-methyladenosine (m6A) is the most common mRNA modification and participates in various immune processes such as interferon production and immune cell regulation. However, the role of m6A in dysregulated immune response of SLE remains unknown. PBMCs from SLE patients were collected to compare the m6A modification profile by methylated RNA immunoprecipitation sequencing (MeRIP-seq). Interferon regulatory factor 4 (IRF4) was identified by combination with MeRIP-seq and RNA-Seq. IRF4 and methyltransferase 3 (METTL3) were detected using qRT-PCR and WB. Clinical significance of IRF4 in SLE patients was explored subsequently. IRF4 expression in B cell subsets of female MRL/lpr mice was detected by flow cytometry. Adeno-associated viruses (AAV) including AAV9-METTL3-OE and/or AAV9-IRF4-sh were treated with female MRL/lpr mice. Autoantibody levels and kidney injury were tested by ELISA, pathological staining, and immunofluorescence. m6A level of IRF4 was detected by MeRIP-qPCR. The downstream effectors of IRF4 contributing to renal pathology were explored by RNA-seq and verified by qRT-PCR. m6A methylation features were obviously aberrant in SLE patients, and IRF4 was the upregulated gene modified by m6A. METTL3 and IRF4 expressions were elevated in SLE patients and kidney of MRL/lpr mice. Clinical analysis indicated that SLE patients with high IRF4 level were more prone to kidney damage. IRF4 expression was especially increased in plasma cells of MRL/lpr mice. METTL3 induced renal IRF4 expression, plasma creatinine, ANA and urine ALB levels, IgG and C3 deposition, and renal damage and plasma cell infiltration were aggravated in MRL/lpr mice. However, IRF4 depletion could partially reduce METTL3-induced kidney damage. Meanwhile, m6A level of IRF4 elevated with METTL3 overexpression. Also, the expression of Cxcl1, Bcl3, and Fos mRNA were significantly reduced after knockdown of IRF4, which were mainly involved in TNF signaling pathway. Our study confirmed that upregulated METTL3 promoting IRF4 expression in an m6A-dependent manner, thus causing plasma cell infiltration-mediated kidney damage of SLE. This provides new evidence for the role of m6A in SLE kidney injury.

The role of vitamin D: a promising pathway to combat neuropsychiatric lupus disorders.

To evaluate neuropsychiatric manifestations in the pristane-induced lupus (PIL) model, as well as to evaluate immunoregulatory effects of vitamin D (vit-D) in the brain of mice with PIL. Eighty female BALB/c mice were divided into six groups with 90 (3 months) and 180 (6 months) days of experimentation: CO3, CO6 (controls), PIL3, PIL6 (pristane-induced lupus), VD3 and VD6 (PIL supplemented with 1,25-dihydroxyvitamin D). Forced-swim, elevated plus maze and Barnes maze were the behavioral tests performed. Expression of pVDR was assessed by immunofluorescence. Brain IgM and IgG deposits were evaluated by double staining fluorescence. Serum IL-6 and IFN-α1 were quantified by ELISA. AUC-ROC curve was also performed for immunoglobulins. PIL and VD showed depressive-like behavior in the forced-swim test and anxious-like behavior in the elevated plus maze test. PIL also presented cognitive and memory impairment in the Barnes maze test. Additionally, PIL and VD presented higher levels of serum IFN-α1, but not IL-6. Mice supplemented with vit-D had reduced IgM and IgG deposits and increased pVDR expression in the brain after 180 days. The AUC-ROC curve demonstrated high sensitivity and specificity for IgM and IgG in the brain. We observed neuropsychiatric manifestations in this model of systemic lupus erythematosus (SLE), strongly corroborating to PIL model being suitable as a neuropsychiatric lupus (NPSLE) model. Vit-D was able to reduce immunoglobulin deposits in the brain and influenced the levels of serum IL-6 in the animals assessed. Also, it improved memory, but it had no effect on depressive and anxious-like behavior.

PARANEOPLASTIC PEMPHIGUS ASSOCIATED WITH NON-HODGKIN'S LYMPHOMA: A CASE REPORT

<p><strong>Introduction</strong>: Paraneoplastic pemphigus is an autoimmune bullous and erosive mucocutaneous syndrome associated with malignancy. First of all, it is associated with lymphoproliferative disorders, but also with solid tumors.</p> <p><strong>Case report</strong>: We present a 73-year-old female patient who developed polymorphic lesions on the skin and mucous membranes after treatment of nonHodgkin's lymphoma. Disseminated pale erythematous macules, exudative papules and plaques, papulovesicles, pustules, targetoid lesions and bullae are present on the skin, mostly with a flaccid roof, some with a hypopyon. Oral mucosal changes included erosions and ulcerations covered by fibrin deposits. Histopathological examination of several biopsies revealed the presence of interface dermatitis, eosinophils, necrotic keratinocytes, as well as intraepidermal cracks with acantholytic cells, dominated by eosinophils. Direct immunofluorescence microscopy of the perilesional skin showed fluorescent intraepidermal reticular IgG deposits, as well as segmental linear IgG deposits along the basement membrane zone. Indirect immunofluorescence microscopy revealed circulating IgG autoantibodies binding to monkey esophagus and rat bladder at a titer of 1:320. Initially, he was treated with systemic corticosteroid therapy, then, in consultation with a hematologist, rituximab therapy was indicated (375 mg/m2, 4 doses once a week). The patient died after the 2nd dose of rituximab.</p> <p><strong>Conclusion</strong>: Considering the different clinical, histopathological and immunological features, paraneoplastic pemphigus presents a challenge for the clinician. Knowledge of different clinical presentations, as well as individualization of therapy with a multidisciplinary approach, are of crucial importance. </p>

POU2F2 activates the Akt/mTOR signalling pathway and enhances B lymphocyte function during diabetic kidney disease by promoting PIK3CD transcription.

Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD) is the predominant isoform of the catalytic subunit of PI3K in lymphocytes. Based on comprehensive bioinformatics, this study explores the functions of PIK3CD in diabetic kidney disease (DKD) progression in mice and B lymphocyte activity. Non-obese diabetic (NOD) mice that spontaneously develop DKD were applied as animal models. Lentiviral vector-mediated PIK3CD silencing was introduced in mice, followed by histological staining and biomarker assessments to evaluate DKD-associated symptoms. The activity of the Akt/mTOR signalling pathway was determined by western blot analysis. Following bioinformatics analyses, the interaction between POU class 2 homeobox 2 (POU2F2) and PIK3CD in B lymphocytes was determined by chromatin immunoprecipitation and luciferase reporter assays. Their functions in B cell function were identified by MTT, flow cytometry and IgG deposition assessment. PIK3CD was found to be highly expressed in the kidney of DKD mice. Knockdown of PIK3CD inactivated the Akt/mTOR signalling, thus ameliorating tissue injury and fibrosis, enhancing the expression of AQP1 and decreasing urinary NGAL contents, UACR, BUN and β-NAG/creatinine ratio. These effects were negated by the Akt-specific activator SC79. POU2F2 was found to promote PIK3CD transcription by binding to its promoter, thus activating the Akt/mTOR pathway. Knockdown of POU2F2 suppressed B cell proliferation in vitro and decreased B cell population and IgG deposition in the mouse kidney. However, these trends were reversed upon additional PIK3CD overexpression. This study demonstrates that POU2F2 mediates PIK3CD-dependent Akt/mTOR signalling activation, thus enhancing B lymphocyte function and promoting DKD progression.

Diagnostic utility of direct immunofluorescence test panels for cutaneous vasculitis: A scoping review.

Due to the immune-mediated nature of non-infectious cutaneous vasculitis, skin biopsy specimens are often submitted for direct immunofluorescence (DIF) testing when vasculitis is considered clinically. However, evidence regarding the clinical value of DIF has not been rigorously appraised. In this scoping review, we aimed to systematically evaluate the peer-reviewed literature on the utility of DIF in vasculitis to assist with the development of appropriate use criteria by the American Society of Dermatopathology. Two electronic databases were searched for articles on DIF and vasculitis (January 1975-October 2023). Relevant case series involving more than or equal to three patients, published in English, and with full-text availability were included. Additional articles were identified manually via reference review. Due to study heterogeneity, findings were analyzed descriptively. Of 255 articles identified, 61 met the inclusion criteria. Cumulatively representing over 1000 DIF specimens, several studies estimated DIF sensitivity to be 75%. While vascular immunoglobulin A (IgA) deposits on DIF were associated with renal disease, other systemic associations were inconsistent. Vascular IgG deposition may be overrepresented in ANCA-associated vasculitis. Granular vascular and epidermal basement membrane zone Ig deposition differentiated hypocomplementemic from normocomplementemic urticarial vasculitis. Few studies have assessed the added value of DIF over routine microscopy alone in vasculitis. This scoping review discovered that DIF testing for vasculitis has been performed not only for diagnostic confirmation of vasculitis but also for disease subtype classification and prediction of systemic associations. Future studies on test sensitivity ofDIF compared to that of histopathology are needed.

Natural history of chronic idiopathic neutropenia of the adult

Chronic idiopathic neutropenia (CIN) is a rare benign condition caused by an immune attack against neutrophils, either primary or in the context of other autoimmune conditions, lymphoproliferative syndromes, and inborn errors of immunity. In this single-center prospective study, 131 adult CIN patients were enrolled (median age 55 years, range: 20–93). At baseline, 56% had anti-neutrophil autoantibodies and 31% had autoimmune comorbidities. Over a median 3-year follow-up, the rate of grade ≥ 2 infections was 42%, with 10% grade ≥ 3, irrespective of neutrophil counts, demographics, and anti-neutrophil antibodies positivity, and G-CSF was used in 6 patients only. No malignant evolution nor deaths were observed. Bone marrow evaluation showed a large granular lymphocyte (LGL) infiltrate in 52%, mostly polyclonal, and hypocellularity in 31% of cases. Immune-histochemistry highlighted deposits of IgG, IgM, and complement fractions C3 and C4d in most cases. Interestingly, 19% of tested patients displayed somatic mutations of myeloid genes with an association with age. In conclusion, adult CIN appears to be a benign condition without life-threatening infections, yet deserving an extensive hematologic evaluation including bone marrow assessment to inform the differential diagnosis.

Progranulin mediates the onset of pristane induced systemic lupus erythematosus

BackgroundsProgranulin (PGRN) is a growth factor-like molecule with diverse roles in homeostatic and pathogenic processes including the control of immune and inflammatory responses. Pathogenic inflammation is a hallmark of systemic lupus erythematosus (SLE) and elevated serum levels of PGRN has been evaluated as a biomarker of disease activity in SLE. However, the role of PGRN in SLE has not been fully investigated. This study is aimed to determine the potential involvements of PGRN in SLE.MethodsWild type (WT) and PGRN knockout (PGRN-/-) C57BL/6 mice received intraperitoneal injection of pristane for induction of a murine model of SLE. Sera were collected every biweekly and levels of anti-dsDNA antibody, IgG, and inflammatory factors were measured. Mice were sacrificed 5 months later and the renal lesions, as well as the proportions of T cell subtypes in the spleen were analyzed.ResultsFollowing exposure to pristane, PGRN-/- mice generated significantly lower levels of anti-dsDNA antibody and IgG relative to WT mice. PGRN-/- mouse kidneys had less IgG and collagen deposition compared with WT mice after pristane injection.ConclusionThe results indicate that PGRN participates in inflammatory response and renal damage in pristane induced SLE models, suggesting that PGRN mediates the onset of SLE.

Abstract P146: Sex-Dependent Regulation of the Endothelin System in Multi-End Organ Inflammation in Lupus-Associated Cardiovascular Disease

Lupus is a chronic autoimmune disease characterized by IgG deposition, Toll-like receptor 7 (TLR7) overactivation, and autoantibody production resulting in end organ inflammation. SLE disproportionally affects women, SLE disproportionally affects women to men (9:1 ratio), with a high prevalence in African American women. Highly vascularized organs are severely impacted by lupus, specifically the kidneys and brain. Recent literature has shown that cardiovascular disease (CVD) has significant detrimental impacts on organ crosstalk. Endothelin-1 (ET-1), a potent vasoconstricting peptide, has been shown elevated in patients with CVD and in patients with lupus independent of disease severity. However, the extent to which ET-1 promotes lupus-associated CVD and end organ cross talk remains to be elucidated. Therefore, we hypothesized that TLR7 overactivation in a murine model of SLE-associated CVD would lead to a sex-dependent regulation of the renal and cerebral ET systems. Female and male lupus-prone B6.Nba2 mice were subjected to bi-weekly treatment with the Resiquimod (R848; TLR7/8 agonist; 100ug/30ul) or vehicle control (Acetone) for one month and subsequently studied for 12 weeks. At 16 weeks, the kidneys and brains were collected for histology and ET system (ET-1, ET A, and ET B ) analysis. Exploration of specific end organ damage demonstrates a profound increase in renal and cerebral IgG complex deposition as well as renal macrophages and T cells in both females and males receiving R848. Renal ET-1 levels displayed no time nor treatment-dependent effects in females, while males exhibited a significant time-dependent increase in expression at the 4 and 16-week timepoints. Interestingly, at the receptor level, neither sex demonstrated differences in ET A nor ET B levels in the kidney. While renal ET-1 level did not change, females demonstrated a significant increase in cerebral ET-1 at the 16-week timepoint, while males trended for increased cerebral ET-1. At the receptor level, females had a trend for increased cerebral ET A expression, while there was no change in males, and neither sex displayed a change in ET B receptor expression. These findings suggest a potential shift towards a pro-inflammatory state via the cerebral ET-1/ET A signaling axis in the R848-treated females. These findings warrant further exploration into the end-organ specific pathophysiological role ET-1/ET A signaling in multiorgan crosstalk in lupus-associated CVD.

IgG4 glycosylation contributes to the pathogenesis of IgG4 Hashimoto's thyroiditis via the complement pathway.

To explore whether IgG4 is involved in the pathogenesis of IgG4 HT. Serum TgAb IgG4 and TPOAb IgG4 were measured in IgG4 HT and non-IgG4 HT. C1q, mannose-binding lectin (MBL), Bb, C3d, C4d, and membrane attack complex (MAC) in thyroid tissues from IgG4 HT, non-IgG4 HT, and controls were examined by immunohistochemistry. We assessed IgG4 and MAC deposition in mouse thyroid by immunohistochemistry after injecting purified IgG4 into mice. The glycosylation patterns of TgAb IgG4 from IgG4 HT were identified by MALDI-TOF-MS. The ability of IgG4 to bind to MBL before and after deglycosylation was assessed by ELISA. MBL and MAC fluorescence were detected in thyrocytes after the addition of IgG4 or deglycosylated IgG4. Serum TgAb IgG4 and TPOAb IgG4 levels were significantly higher in the IgG4 HT group. MBL, Bb, C3d, C4d, and MAC levels were significantly higher in the thyroid tissues of IgG4 HT than in non-IgG4 HT (all P < 0.001). IgG4 colocalized with MBL by immunofluorescence. In mice, follicular cell structure disruption was observed after the injection of IgG4 from IgG4 HT, as well as the colocalization of IgG4 with MAC. High levels of TgAb IgG4 glycosylation patterns, including monogalactose glycan (G1F), galactose-deficient glycan (G0F), and high-mannose glycan (M5), were detected in IgG4 HT. After deglycosylation, IgG4 reduced its ability to bind to MBL, and there was low MBL and MAC activation in thyrocytes. High levels of IgG4 glycosylation patterns, including G1F, G0F, and M5, may activate the complement lectin pathway, thereby participating in the pathogenesis of IgG4 HT.