Some background on melatonin:
http://www.mayoclinic.com/health/melatonin/NS_patient-melatonin. You should probably ask Abbott about
this question. A contact for emailing questions to them can be found at the bottom of this page:
http://www.humira.com/I can't find much about
the combination, but there was a report of melatonin triggering Crohn's-like symptoms in one case. There are no details about
this report except an offer to sell the report for $50 to anyone interested. It appears to be a letter to the editor of some journal, so who knows whether it can be relied on. There are also positive reports citing benefits from taking melatonin for Crohn's.