Ak against glomerular basement membrane $$$

antibodies directed against type IV collagen of the glomerular basement membrane. Then there are AK that capture other epitopes, or AK against entactin, laminin and other intermediate filaments.

AK detection in serum: A positive ELISA test is the diagnostic criterion.

Immunohistological detection: Typical linear IgG deposits on the basement membrane. Target AG is the C-terminus of the alpha3(IV) chain of type IV collagen in the alveolar and glomerular basement membrane

Differential diagnosis of the autoantibody spectrum in pulmonary syndromes

• Anti-GBM-AK (Goodpasture's syndrome, anti-GBM glomerulonephritis)
• cANCA /IFT, ELISA (Wegener's granulomatosis, idiopathic RPGN
• pANCA/IFT,ELISA (microscopic polyarteritis, Churg-Strauss syndrome; idiopathic RPGN
• Anti-ds-DNA (Lupus erythematosus)
• Cryoglobulins (Cryoglobulinemia)
• Without Auto-AK (Purpura Schoenlein-Henoch, Postinfectious Glomerulonephritis

1. Böhm B (2018) Thyroid hormones. In: Neumeister B et al (Eds) Clinical guide to laboratory diagnostics. Elsevier GmbH S. 421-422