RESUMO

A T-cell-independent (TI) pathway activated by microbiota results in the generation of low-affinity homeostatic IgA with a critical role in intestinal homeostasis. Moderate aerobic exercise (MAE) provides a beneficial impact on intestinal immunity, but the action of MAE on TI-IgA generation under senescence conditions is unknown. This study aimed to determine the effects of long-term MAE on TI-IgA production in young (3 month old) BALB/c mice exercised until adulthood (6 months) or aging (24 months). Lamina propria (LP) from the small intestine was obtained to determine B cell and plasma cell sub-populations by flow cytometry and molecular factors related to class switch recombination [Thymic Stromal Lymphopoietin (TSLP), A Proliferation-Inducing Ligand (APRIL), B Cell Activating Factor (BAFF), inducible nitric oxide synthase (iNOS), and retinal dehydrogenase (RDH)] and the synthesis of IgA [α-chain, interleukin (IL)-6, IL-21, and Growth Factor-ß (TGF-ß)]; and epithelial cells evaluated IgA transitosis [polymeric immunoglobulin receptor (pIgR), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-4] by the RT-qPCR technique. The results were compared with data obtained from sedentary age-matched mice. Statistical analysis was computed with ANOVA, and p < 0.05 was considered to be a statistically significant difference. Under senescence conditions, MAE promoted the B cell and IgA+ B cells and APRIL, which may improve the intestinal response and ameliorate the inflammatory environment associated presumably with the downmodulation of pro-inflammatory mediators involved in the upmodulation of pIgR expression. Data suggested that MAE improved IgA and downmodulate the cytokine pro-inflammatory expression favoring homeostatic conditions in aging.

Assuntos

Envelhecimento , Homeostase , Imunoglobulina A , Camundongos Endogâmicos BALB C , Condicionamento Físico Animal , Animais , Imunoglobulina A/metabolismo , Imunoglobulina A/imunologia , Camundongos , Envelhecimento/imunologia , Citocinas/metabolismo , Linfócitos B/imunologia , Linfócitos B/metabolismo , Fator Ativador de Células B/metabolismo , Fator Ativador de Células B/genética , Mucosa Intestinal/metabolismo , Mucosa Intestinal/imunologia , Intestino Delgado/imunologia , Intestino Delgado/metabolismo , Masculino , Plasmócitos/imunologia , Plasmócitos/metabolismo , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/metabolismo , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genética

RESUMO

Introduction: Kimura's disease (KD) is a rare chronic inflammatory disorder characterized by subcutaneous lymphoid hyperplasia with peripheral eosinophilia. Kidney involvement is reported in 15%-18% of adult patients with KD, in many cases as nephrotic syndrome. We present a case of overlapping membranous nephropathy and IgA nephropathy associated with KD. Case report: A 27-year-old man was admitted with a history of bilateral leg edema for the last 2 months and concomitant progressive increase of cervical mass and fever. Laboratory findings were as follows: peripheral leukocyte count, 10,080/mm³; eosinophils, 3,200/mm³ (31.7%); serum creatinine, 0.83 mg/dL; and eGFR: 140 mL/min per 1.73 m2. Urinalysis revealed the presence of hematuria and proteinuria and the following results: 24-h proteinuria, 12.9 g; serum albumin, 1.3 g/dL; and elevated IgE level, 750 kU/L. Serologies for hepatitis B, hepatitis C, HIV, and VDRL were all negative. Complement C3 and C4 levels were normal. No monoclonal protein was detected in blood and urine. Parasite infestation was discarded. A biopsy of the cervical lymph node revealed eosinophilic lymphoid hyperplasia, suggesting KD. A kidney biopsy revealed findings consistent with the overlapping of membranous nephropathy with IgA nephropathy. The patient was treated for KD with prednisone 1 mg/kg/d with progressive dose tapering and posterior association of methotrexate 15 mg/week. A renin-angiotensin system inhibitor was prescribed for nephrotic syndrome. The cervical mass regressed, and proteinuria achieved partial remission, with an increase in serum albumin level and normalization of eosinophils and IgE levels. Conclusion: Although uncommon, kidney involvement must be considered in patients with KD. Glomerular diseases are the most frequent form of kidney injury.

Assuntos

Glomerulonefrite por IGA , Glomerulonefrite Membranosa , Doença de Kimura , Humanos , Adulto , Glomerulonefrite por IGA/diagnóstico , Glomerulonefrite por IGA/complicações , Glomerulonefrite por IGA/tratamento farmacológico , Masculino , Glomerulonefrite Membranosa/tratamento farmacológico , Glomerulonefrite Membranosa/diagnóstico , Glomerulonefrite Membranosa/imunologia , Doença de Kimura/diagnóstico , Doença de Kimura/complicações , Doença de Kimura/tratamento farmacológico , Biópsia , Rim/patologia

RESUMO

Introduction: Lrba is a cytoplasmic protein involved in vesicular trafficking. Lrba-deficient (Lrba-/-) mice exhibit substantially higher levels of IgA in both serum and feces than wild-type (WT) mice. Transforming growth factor ß1 (TGFß1) and its receptors (TGFßR I and II) is essential for differentiating IgA+ B cells. Furthermore, increased IgA production suggests a potential connection between Lrba and the TGFßR signaling pathway in IgA production. However, the specific function of Lrba in B cell biology remains unknown. Aim: Given the increased IgA levels in Lrba-/- mice, the goal in this work was to explore the lymph organs where the switch to IgA occurs, and if TGFßR function is affected. Methods: Non-immunized Lrba-/- mice were compared with Lrba+/+ mice. IgA levels in the serum and feces, as well as during peripheral B cell development, were determined. IgA+ B cells and plasma cells were assessed in the small intestine and secondary lymphoid organs, such as the spleen, mesenteric lymph nodes, and Peyer's patches. The TGFßR signaling pathway was evaluated by determining the expression of TGFßR on B cells. Additionally, SMAD2 phosphorylation was measured under basal conditions and in response to recombinant TGFß. Finally, confocal microscopy was performed to investigate a possible interaction between Lrba and TGFßR in B cells. Results: Lrba-/- mice exhibited significantly higher levels of circulating IgA, IgA+ B, and plasma cells than in peripheral lymphoid organs those in WT mice. TGFßR expression on the membrane of B cells was similar in both Lrba-/- and Lrba+/+ mice. However, intracellular TGFßR expression was reduced in Lrba-/- mice. SMAD2 phosphorylation showed increased levels under basal conditions; stimulation with recombinant TGFß elicited a poorer response than in that in Lrba+/+ B cells. Finally, we found that Lrba colocalizes with TGFßR in B cells. Conclusion: Lrba is essential in controlling TGFßR signaling, subsequently regulating SMAD2 phosphorylation on B cells. This mechanism may explain the increased differentiation of IgA+ B cells and production of IgA-producing plasma cells.

Assuntos

Linfócitos B , Diferenciação Celular , Imunoglobulina A , Transdução de Sinais , Animais , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Diferenciação Celular/imunologia , Imunoglobulina A/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Proteína Smad2/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo

RESUMO

INTRODUCTION: IgA nephropathy is the most common glomerulopathy in the world, it has a wide clinical expression, from asymptomatic to rapidly progressive glomerulonephritis. The definitive diagnosis is renal biopsy, within which the IgA pattern can be identified, including thrombotic microangiopathy. CLINICAL CASE: 28-year-old female patient, with a history of preeclampsia in the last pregnancy, presents high blood pressure, hematuria and proteinuria. Study begins with initially negative results. Renal biopsy confirms IgA nephropathy with thrombotic microangiopathy. DISCUSSION: Vascular damage is underestimated in IgA nephropathy. Thrombotic microangiopathy can be associated with various clinical manifestations, however when it is associated with IgA Nephropathy it is usually associated with proteinuria, arterial hypertension and elevation of creatinine. In the presence of microangiopathy, secondary causes must be ruled out. In general, there is no pathognomonic serological marker. Eventually patients could benefit from the use of eculizumab. CONCLUSION: IgA nephropathy is the most common glomerulopathy worldwide; there is a wide range of clinical presentations, among which thrombotic microangiopathy can be found. This presentation is associated with a higher risk of progression to end-stage renal disease.

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INTRODUCCIÓN: La nefropatía por IgA es la glomerulopatía más frecuente en el mundo, tiene una amplia expresión clínica, desde asintomática hasta glomerulonefritis rápidamente progresivas. El diagnóstico definitivo es la biopsia renal, dentro de las cuales se puede identificar el patrón de la IgA, dentro de los cuales está la microangiopatía trombótica. CASO CLÍNICO: Paciente femenina 28 años, con antecedentes de preeclampsia en último embarazo, presenta hipertensión arterial, hematuria y proteinuria. Se inicia estudio con resultados inicialmente negativos. Biopsia renal confirma nefropatía por IgA con microangiopatía trombótica. DISCUSIÓN: En la nefropatía por IgA se subestima el daño vascular. La microangiopatía trombótica se puede asociar con varias manifestaciones clínicas, sin embargo, cuando está asociada a NIgA suele estar asociado con proteinuria, hipertensión arterial y elevación y creatinina. Ante la presencia de microangiopatía, se deben descartar causas secundarias de la misma. En general no existe un marcador serológico patognomónico. Eventualmente los pacientes se podrían beneficiar del uso de eculizumab. CONCLUSIÓN: La nefropatía por IgA es la glomerulopatía más frecuente a nivel mundial, existe una gran gama de presentaciones clínicas, dentro de las cuales se puede encontrar microangiopatía trombótica. Esta última presentación se asocia con mayor riesgo de progresión a enfermedad renal en etapa terminal.

Assuntos

Humanos , Feminino , Adulto , Vasos Sanguíneos/patologia , Microangiopatias Trombóticas/epidemiologia , Glomerulonefrite por IGA/epidemiologia , Rim/patologia , Imuno-Histoquímica , Prevalência , Microangiopatias Trombóticas/etiologia , Microangiopatias Trombóticas/patologia , Glomerulonefrite por IGA/complicações , Glomerulonefrite por IGA/patologia , Hipertensão/complicações

RESUMO

The worldwide spread of SARS-CoV-2 has led to a significant economic and social burden on a global scale. Even though the pandemic has concluded, apprehension remains regarding the emergence of highly transmissible variants capable of evading immunity induced by either vaccination or prior infection. The success of viral penetration is due to the specific amino acid residues of the receptor-binding motif (RBM) involved in viral attachment. This region interacts with the cellular receptor ACE2, triggering a neutralizing antibody (nAb) response. In this study, we evaluated serum immunogenicity from individuals who received either a single dose or a combination of different vaccines against the original SARS-CoV-2 strain and a mutated linear RBM. Despite a modest antibody response to wild-type SARS-CoV-2 RBM, the Omicron variants exhibit four mutations in the RBM (S477N, T478K, E484A, and F486V) that result in even lower antibody titers. The primary immune responses observed were directed toward IgA and IgG. While nAbs typically target the RBD, our investigation has unveiled reduced seroreactivity within the RBD's crucial subregion, the RBM. This deficiency may have implications for the generation of protective nAbs. An evaluation of S1WT and S2WT RBM peptides binding to nAbs using microscale thermophoresis revealed a higher affinity (35 nM) for the S2WT sequence (GSTPCNGVEGFNCYF), which includes the FNCY patch. Our findings suggest that the linear RBM of SARS-CoV-2 is not an immunodominant region in vaccinated individuals. Comprehending the intricate dynamics of the humoral response, its interplay with viral evolution, and host genetics is crucial for formulating effective vaccination strategies, targeting not only SARS-CoV-2 but also anticipating potential future coronaviruses.

RESUMO

Background: Respiratory tract infections remain among the leading causes of mortality worldwide. The COVID-19 pandemic has highlighted the importance of mucosal immunity in defending against infectious agents. Vitamin A is known to influence the production of secretory immunoglobulin A (SIgA) predominantly in the gut, where it is a critical component of the first line of defense on mucosal surfaces. Methods: This cross-sectional study, conducted 14 days post-positive COVID-19 diagnosis, aimed to determine the relationship between the nutritional status of vitamin A and SIgA levels in COVID-19 outpatients. Serum and saliva samples were collected. Vitamin A nutritional status was determined based on the assessment of dietary intake and the analysis of retinol-binding protein 4 (RBP4). SIgA levels were analyzed from salivary samples. In addition, serum antibodies were analyzed. Results: Dietary vitamin A intake and RBP4 levels positively correlated with SIgA. Patients with higher vitamin A intake showed higher SIgA/IgG1 and SIgA/IgG3 ratios, while those with higher RBP4 levels showed higher SIgA/IgM, SIgA/IgG1, and SIgA/IgG2 ratios. Conclusions: These findings underscore a significant correlation between vitamin A nutritional status and SIgA levels in COVID-19 outpatients, which may suggest the potential importance of maintaining optimal vitamin A levels for the prevention of viral infections.

RESUMO

Augmentation of glycoprotein synthesis requirements induces endoplasmic reticulum (ER) stress, activating the unfolded protein response (UPR) and triggering unconventional XBP1 splicing. As a result, XBP1s orchestrates the expression of essential genes to reduce stress and restore homeostasis. When this mechanism fails, chronic stress may lead to apoptosis, which is thought to be associated with exceeding a threshold in XBP1s levels. Glycoprotein assembly is also affected by glutamine (Gln) availability, limiting nucleotide sugars (NS), and preventing compliance with the increased demands. In contrast, increased Gln intake synthesizes ammonia as a by-product, potentially reaching toxic levels. IgA2m(1)-producer mouse myeloma cells (SP2/0) were used as the cellular mammalian model. We explored how IgA2m(1)-specific productivity (qIgA2m(1)) is affected by (i) overexpression of human XBP1s (h-XBP1s) levels and (ii) Gln availability, evaluating the kinetic behavior in batch cultures. The study revealed a two and a five-fold increase in qIgA2m(1) when lower and higher levels of XBP1s were expressed, respectively. High h-XBP1s overexpression mitigated not only ammonia but also lactate accumulation. Moreover, XBP1s overexpressor showed resilience to hydrodynamic stress in serum-free environments. These findings suggest a potential application of h-XBP1s overexpression as a feasible and cost-effective strategy for bioprocess scalability.

RESUMO

OBJECTIVE: To evaluate the relationship between genetic haplotypes associated with celiac disease (Human Leucocyte Antigen [HLA] DQ2 and DQ8) with the diagnosis, clinical presentation, and location of endometriosis in Brazilian women. METHOD: A retrospective cross-sectional study, was conducted in a Tertiary hospital. PATIENTS: Women aged 18-50 years who underwent HLA-DQ2 and HLA-DQ8 haplotype analysis. INTERVENTION: The patients were divided into endometriosis and control groups and evaluated for symptoms; endometriosis location, American Society for Reproductive Medicine (ASRM) stage, and the presence of anti-tissue transglutaminase IgA (anti-TgA), HLA-DQ2, and HLA-DQ8 markers. RESULTS: A total of 434 consecutive patients with (n = 315) and without (n = 119) endometriosis were included. Pain and infertility were more frequent in the endometriosis group than in the control group. The presence of HLA-DQ2, HLA-DQ8, and anti-TgA was similar between both groups. The presence of HLA-DQ2 and HLA-DQ8 markers did not differ based on age, pain symptoms, ASRM stage, or endometriosis location. CONCLUSION: Although there are similarities in inflammatory markers and pathophysiology between celiac disease and endometriosis, this study found no significant associations in the presence of HLA-DQ2 or HLA-DQ8 haplotypes and endometriosis.

Assuntos

Doença Celíaca , Endometriose , Antígenos HLA-DQ , Humanos , Feminino , Endometriose/genética , Estudos de Casos e Controles , Estudos Retrospectivos , Haplótipos , Doença Celíaca/genética , Estudos Transversais , Dor

RESUMO

BACKGROUND: IgA nephropathy (IgAN) is a common primary glomerular disease. The O-glycosylation status of IgA1 plays a crucial role in disease pathophysiology. The level of poorly-O-galactosylated IgA1, or galactose-deficient IgA1 (Gd-IgA1), has also been identified as a potential biomarker in IgAN. We sought to examine the value of serum Gd-IgA1 as a biomarker in IgAN, by investigating its association with clinical, laboratory, and histopathological features of IgAN. METHODS: The review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations and was registered in PROSPERO (CRD42021287423). The literature search was conducted in PubMed, Web of Science, Cochrane, and Scopus, and the selected articles were evaluated for eligibility based on predefined criteria. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale. Statistical analysis was performed to calculate effect sizes and assess heterogeneity among the studies. RESULTS: This review analyzed 29 out of 1,986 studies, conducted between 2005 and 2022, with participants from multiple countries. Gd-IgA1 levels were not associated with age and gender, while associations with hypertension, hematuria, and proteinuria were inconsistent. In the meta-analyses, a correlation between serum Gd-IgA1 and estimated glomerular filtration rate was identified, however, the relationships between Gd-IgA1 levels and chronic kidney disease (CKD) stage and progression to kidney failure were inconsistent. CONCLUSIONS: Serum Gd-IgA1 levels were not associated with validated prognostic risk factors, but were negatively correlated with kidney function. Further research in larger studies using standardized assays are needed to establish the value of Gd-IgA1 as a prognostic risk factor in IgAN.

RESUMO

Introduction: Kidney disease is a well-known extraintestinal manifestation (EIM) associated with inflammatory bowel disease (IBD), with a variety of underlying etiologies. However, little is known about the overall outcomes and predictors. Methods: This is a retrospective, observational cohort study. Patients with IBD in whom a native kidney biopsy was performed at Mayo Clinic (Rochester, MN) between 1994 and 2022, were included. Demographic, clinical, and histologic characteristics of prognostic interest were collected. The main outcomes were kidney failure, disease remission, kidney function changes at last follow-up, and death. Results: From a total cohort of 318 patients, we selected a study group of 111 patients followed-up with at our institution (45 ulcerative colitis [UC] and 66 Crohn's disease [CD]), with a mean age of 48 ± 17 years (40% females). IgA nephropathy (IgAN), chronic interstitial nephritis (CIN), and acute interstitial nephritis (AIN) were the most common diagnoses (22%, 19%, 13%, respectively). Median estimated glomerular filtration rate (eGFR) at presentation was 30 ml/min per 1.73 m2 (interquartile range [IQR]: 17-54) and urinary protein-to-creatinine ratio [UPCR] 0.8 g/g (0.3-3.4), without differences between IBD types. During a median follow-up of 59 months (12-109), 29 patients (26%) reached kidney failure. By multivariable analysis, the main predictors of kidney failure were age (hazard ratio [HR]: 1.04; P = 0.002), baseline eGFR (HR: 0.94; P = 0.003) and histologic chronicity score (HR: 4.01; P < 0.001). Therapeutic management varied according to underlying etiology. Global survival (kidney failure + death) was significantly better in patients who achieved complete or partial remission, or stabilization or improvement of kidney function. Conclusion: One-fourth of patients with IBD with kidney disease may reach kidney failure, and the main determinants of this outcome is age, baseline eGFR, and degree of chronicity in kidney biopsy.