All patients complete diary cards for the first month of the study in order to determine compliance in providing a daily record of symptoms and medication taken. All compliant patients receive subcutaneously injected heparin twice daily, inhaled heparin daily, or matched saline placebo in a random order. Each of the three drug administration periods lasts 2 months, for a total of 6 months of treatment. Patients who have a flare in disease activity that requires hospitalization are terminated from that drug administration period of the study.