The Role of IgA and IgG Immune Complexes in IgA Nephropathy

IgA nephropathy (IgAN), the most common primary glomerular disease worldwide, is characterized by glomerular deposition of IgA1-containing immune complexes. The IgA1 hinge region (HR) has up to six clustered O-glycans consisting of Ser/Thr-linked N-acetylgalactosamine usually with β1,3-linked galactose and variable sialylation. Circulating levels of IgA1 with abnormally O-glycosylated HR, termed galactose-deficient IgA1 (Gd-IgA1), are increased in patients with IgAN. Current evidence suggests that IgAN is induced by multiple sequential pathogenic steps, and production of aberrantly glycosylated IgA1 is considered the initial step. Thus, the mechanisms of biosynthesis of aberrantly glycosylated IgA1 and the involvement of aberrant glycoforms of IgA1 in disease development have been studied. Furthermore, Gd-IgA1 represents an attractive biomarker for IgAN, and its clinical significance is still being evaluated. To elucidate the pathogenesis of IgAN, it is important to deconvolute the biosynthetic origins of Gd-IgA1 and characterize the pathogenic IgA1 HR O-glycoform(s), including the glycan structures and their sites of attachment. These efforts will likely lead to development of new biomarkers. Here, we review the IgA1 HR O-glycosylation in general and the role of aberrantly glycosylated IgA1 in the pathogenesis of IgAN in particular.

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Experimental evidence of pathogenic role of IgG autoantibodies in IgA nephropathy

Journal of Autoimmunity ◽

10.1016/j.jaut.2021.102593 ◽

2021 ◽

Vol 118 ◽

pp. 102593

Author(s):

Zina Moldoveanu ◽

Hitoshi Suzuki ◽

Colin Reily ◽

Kenji Satake ◽

Lea Novak ◽

...

Keyword(s):

Experimental Evidence ◽

Iga Nephropathy ◽

Pathogenic Role

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Role of Circulating Immune Complexes in the Pathogenesis of Canine Leishmaniasis: New Players in Vaccine Development

Microorganisms ◽

10.3390/microorganisms9040712 ◽

2021 ◽

Vol 9 (4) ◽

pp. 712

Author(s):

Cristina Cacheiro-Llaguno ◽

Nuria Parody ◽

Marta R. Escutia ◽

Jerónimo Carnés

Keyword(s):

Immune Complexes ◽

Vaccine Development ◽

Correct Diagnosis ◽

Circulating Immune Complexes ◽

Response To Treatment ◽

Canine Leishmaniasis ◽

Leishmania Infection ◽

Serum Samples ◽

Humoral Immune

During canine visceral leishmaniasis (CanL), due to Leishmania infantum (L. infantum), uncontrolled infection leads to a strong humoral immune response. As a consequence of the production of high antibody levels and the prolonged presence of parasite antigens, circulating immune complexes (CIC) are formed, which can be deposited in certain organs and tissues, inducing vasculitis, uveitis, dermatitis and especially glomerulonephritis and renal failure. A method to detect CIC and quantify their levels in serum samples from dogs infected with L. infantum has been recently described. It allowed demonstration of a correlation between CIC levels and disease severity. Thus, CIC measurement may be useful for diagnosis, assessment of disease progression and monitoring response to treatment. This is an interesting finding, considering that there remains an urgent need for identification of novel biomarkers to achieve a correct diagnosis and for optimal disease staging of dogs suffering from Leishmania infection. The objective of the present review is to shed light on the role of CIC in CanL, as well as to highlight their potential use not only as diagnostic and prognostic biomarkers but also as a valuable tool in vaccine development and new immunotherapy strategies to prevent or control disease outcome.

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Evaluation of Serum Immunoglobulins (IgG, IgA, IgM) and Circulating Immune Complexes in Oral Precancer and Cancer Patients

Global Medical Genetics ◽

10.1055/s-0041-1725157 ◽

2021 ◽

Author(s):

Pooja Madki ◽

Mandya Lakshman Avinash Tejasvi ◽

Geetha Paramkusam ◽

Ruheena Khan ◽

Shilpa J.

Keyword(s):

Oral Cancer ◽

Immune Complexes ◽

Serum Levels ◽

Circulating Immune Complexes ◽

Oral Cancers ◽

Cancer Group ◽

Oral Precancer ◽

Serum Iga ◽

The Mean

Abstract Objectives The aim of the present study is to evaluate the role of immunoglobulins (IgA, IgG, and IgM) and circulating immune complexes (CIC) as tumor marker in oral cancer and precancer patients. Materials and Methods The present study was performed on 45 individuals subdivided into three groups, that is, oral precancer, oral cancer and healthy individuals, and levels of immunoglobulins, and CIC was estimated by turbidometry and ELISA method. Results In the present study, the mean serum IgA levels in oral precancer were 161.00 ( ± 118.02) mg/dL, oral cancers were 270.67 ( ± 171.44) mg/dL, and controls were 133.73 ( ± 101.31) mg/dL. Mean serum levels of IgG in oral precancer were 1,430.87 ( ± 316) mg/dL, oral cancers were 1,234.27 ( ± 365.42) mg/dL, and controls were 593.87 ( ± 323.06) mg/dL. Conclusion We found that the levels of serum IgG and IgA were elevated consistently in precancer and cancer group, and Serum IgM levels were increased only in precancer. Also, significant increase in serum CIC levels were seen in oral precancer and cancer group on comparison with control.

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