IgA nephropathy during treatment with TNF-alpha blockers: Could it be predicted?

Immunoglobulin A (IgA) nephropathy (IgAN) may sometimes be related to exposure to pharmacological agents, among which anti-Tumor Necrosis Factor (TNF)-alpha agents. The characteristic pathological feature is a deposition of IgA-containing immune complexes in vessel walls in the kidney mesangium. The link between TNF-alpha blockers and IgAN may be hypothesized examining diseases which share pathologic features. In this respect, idiopathic IgAN and Henoch Schonlein Purpura have been the object of studies revealing a pathogenetic role of aberrant glycosylation of IgA1 molecules. The Authors suggest that anti-drug antibodies against glycan structures of TNF-alpha inhibitors may cross react against serum aberrant IgA1 leading to large antigen-antibody complexes. These large polymeric IgA complexes are then able to deposit in the mesangium and activate the complement cascade. Such hypothesis may be tested by measuring serum levels of galactose-deficient IgA1 of patients developing IgAN following introduction of TNF-alpha blockers. Such a test would be useful also before administration of anti-TNF alpha agents. The presence of aberrant IgA1 may represent a contraindication for treatment with TNF blockers.