Overview

IgA nephropathy is the most common primary glomerulonephritis in adults.

• Peak incidence: second to third decades of life

• Sex: ♂ > ♀ (2:1)

• Ethnicity: more common in the Asian population (worldwide)

• The cause is still not entirely understood.

• Most likely mechanism: an increased number of defective, circulating IgA antibodies are synthesized (often triggered by mucosal infections, i.e., upper respiratory tract and gastrointestinal infections) → IgA antibodies form immune complexes that deposit in the kidney → glomerulonephritis (type III hypersensitivity reaction)

The course of the disease is highly variable and can manifest in the following forms:

• Asymptomatic

• Recurring episodes of:

  • Gross or microscopic hematuria

  • Flank pain

  • Low-grade fever

  • And/or nephritic syndrome (including hypertension)

  • Usually during or immediately following a respiratory or gastrointestinal infection [6]

• Can progress to RPGN and/or nephrotic syndrome (< 10% of patients)

• Up to 50% of patients progress to end-stage renal disease within 20–25 years.

IgA nephropathy and IgA vasculitis are both IgA-mediated vasculitides triggered by a mucosal infection. IgA vasculitis most commonly occurs in children < 10 years of age and affects multiple organ systems (palpable purpura, abdominal pain, arthralgia). IgA nephropathy is limited to the kidneys and typically affects adults.