Patients receive MOAB IV over 5 hours on days 7-10 during courses 2 and 4 and on days 3-6 during courses 1, 3, and 5; sargramostim (GM-CSF) IV over 2 hours or subcutaneously daily on days 0-13 during courses 1, 3, and 5; interleukin-2 IV continuously on days 0-3 and 7-10 during courses 2 and 4; and oral isotretinoin twice daily on days 14-27 during courses 2 and 4 and on days 10-23 during courses 3 and 5. Treatment repeats every 24-32 days for 5 courses in the absence of unacceptable toxicity.