No. 36: Nov-Dec 1984
"Most of the effort directed at understanding the problems of allergy has focused on the interacting components of the immune system. The possibility that histamine may be released as a learned response has now been tested. In a classical conditioning procedure in which an immunologic challenge was paired with the presentation of an odor, guinea pigs showed a plasma histamine increase when presented with the odor alone. This suggests that the immune response can been hanced through activity of the central nervous system."
The article begins by noting that many anecdotal reports suggest that allergic reactions can be induced by suggestion; viz., an allergy to roses induced by an artificial rose. (Russell, Michael, et al; "Learned Histamine Release," Science, 225:733, 1984.)