 With the assent of the attending physician, informed consent will be obtained from the patient or next of kin as soon as possible after case identification. Physiologic measurements and specimen collection will begin at the time of entry into the study. Three days after the patient has met criteria for ALIARDS or at entry into the study whichever is later, heshe will be randomized to receive recombinant human GM-CSF 250 mcgM2 or placebo, administered by slow intravenous infusion once daily for 14 days. 