This patient has Goodpasture syndrome, which is a rare, severe autoimmune disease in which antibodies directed against the basement membrane in pulmonary alveoli and renal glomeruli predispose for hemoptysis and progressive renal disease. These patients can die because of exsanguination, asphyxiation by blood, or renal failure. Aggressive immunosuppression coupled with management of complications may be lifesaving. Goodpasture disease is often cited as an example of a Type II hypersensitivity reaction, and a very similar pathologic mechanism produces the blistering disease bullous pemphigoid, in which antibodies are directed against the basement membrane region of the skin. The immunologic basis of Graves disease is stimulation of TSH receptors by anti-receptor antibodies. The immunologic basis of hereditary angioedema is inadequate C1 esterase inhibitor activity. The immunologic basis of rheumatoid ahritis is the presence of immune complexes within joints.