Individuals appear to be predisposed to antiglomerular basement membrane (anti-GBM) disease by carrying a predisposing human leucocyte antigen type, DRB1*1501 being identified as the highest risk factor, and there are likely to be other predisposing genes or influences on top of which a relatively rare ‘second hit’ leads to the development of autoimmunity. In anti-GBM disease this appears to have a self-perpetuating, accelerating component, that may be to do with antibodies and altered antigen presentation. Lymphocyte depletion may also predispose to the disease.
A number of second hits have been identified and they seem to share a theme of damage to the glomerulus. There may be a prolonged (months to years) and usually subclinical phase in anti-GBM disease in which usually relatively low level antibody titres are associated with variable haematuria, sometimes minor pulmonary haemorrhage, but often no symptoms.
Damage to the lung seems to determine whether there is a pulmonary component to the disease. Without pulmonary damage caused typically by smoking, inhalation of other fumes, and potentially infection or oxygen toxicity, the disease remains an isolated kidney disease.
Antibodies appear to be an important component of the disease, but cell-mediated immunity is also critical to the clinical picture. In animal models, cell-mediated immunity triggered by the GBM antigen can cause severe renal damage in the absence of pathogenic antibody. The development of specific antibody also requires T-cell sensitization and help, and suppressing the response is likely to require suppressing both antibody and cell-mediated immunity.
Antibodies recognize one major and some other epitopes, which are now well described. T-cell epitopes are becoming better understood. Evidence from animal models also suggests that the damage in anti-GBM disease is dependent on complement, macrophages, and neutrophils.
Lgl1 Is Suppressed in Oxygen Toxicity Animal Models of Bronchopulmonary Dysplasia and Normalizes During Recovery in Air
