Anti-Glomerular Basement Membrane

Goodpasture’s syndrome is an autoimmune condition characterised by rapidly progressing glomerulonephritis (RPGN) commonly accompanied by pulmonary haemorrhage. The disease is often fatal if not diagnosed and treated. The presence of anti-glomerular basement membrane antibodies (also known as Goodpasture’s antibodies) and in particular antibodies against the C-terminal end of the alpha-3 chain of type IV collagen is diagnostic of Goodpasture’s syndrome. A negative test for GBM rules out active Goodpasture’s, however, a positive test indicates a requirement for urgent treatment, a high risk of lung haemorrhage and poor prognosis of the patient.

In patients presenting with RPGN a wider serological evaluation is necessary as only about 15% of patients will express anti-GBM. The majority of patients will have ANCA and a minority will have other disorders. The incidence of disease is low with reports of around 0.5-1.0 per million in the general population. Male or female patients are roughly equal, however, male patients are twice as likely to suffer from lung haemorrhage. More recently a subset of RPGN has been identified who have both anti-GBM and ANCA. These patients tend to have lower levels of anti-GBM and better prognosis.

Antibodies to GBM are generally of the IgG class with IgG1 predominant. IgA antibodies have also been demonstrated but the significance of this class of antibodies is unclear.