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IgA nephropathy: A vasculitis?
Author(s) -
KONG Norella CT
Publication year - 1997
Publication title -
nephrology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 61
eISSN - 1440-1797
pISSN - 1320-5358
DOI - 10.1111/j.1440-1797.1997.tb00183.x
Subject(s) - medicine , anti nuclear antibody , autoantibody , nephropathy , vasculitis , immunology , glomerulonephritis , immunoglobulin a , pathology , autoimmunity , fibrinoid necrosis , palpable purpura , antibody , kidney , disease , henoch schonlein purpura , immunoglobulin g , diabetes mellitus , endocrinology
Summary: Vasculitis is an inflammation of blood vessels which leads to necrosis and infarction of the endorgans involved. IgA nephropathy (IgAN) is the kidney‐limited expression of a single disease with Henoch‐Schonlei purpura as the systemic vasculitic form. Renal histology is indistinguishable except for the chronic progressive nature of IgAN, in 20–30% of patients. A common immunopathogenesis occurs in which a genetic abnormality enhances IgA immune response to exogeneous (and endogenous) antigens in mucosae with the excessive production of macromolecular IgA 1 . Renal damage is triggered by mesangial deposits of IgA 1 . Both are associated with chronic liver disease, gut neoplasms and lymphomas and IgAN, in particular with autoimmune diseases such as dermatitis herpetiformes, coeliac disease, ankylosing spondylitis and Reiter's disease. Immunodysregulation with reduced T suppressor cell function and enhanced T helper cell function with resultant autoantibodies is highly reminiscent of systemic lupus erythematosus (SLE). The many autoantibodies and characteristic vasculitic lesions of SLE are well documented. Autoantibodies have been demonstrated in IgAN and include cold‐reactive antinuclear antibodies (ANA), IgA‐rheumatoid factor, IgA‐antinuclear cytoplasmic antibody, anti‐endothelial cell antibody (AECA) and IgA‐fibrinonecrin. Their clinical significance remains controversial. Extrarenal involvement of the skin, eyes and joints occasionally occurs, although systemic capillaritis is rarely reported. It is tempting to speculate that the severe renal biopsy changes of necrosis, polymorph infiltrate and crescent formation occurring in a third of IgAN patients reflect true glomerular capillaritis. Nevertheless, on the balance of current evidence, IgAN cannot be classified as a vasculitis.