Current concepts on the relationship between immunodeficiency and allergy.

The relationship between immunodeficiency and atopy represent one of the most significant yet at the same time one of the least understood phenomena in medicine today. This paper will therefore attempt to review the present state of knowledge. Current data focusing on the role of histamine as a negative feed-back regulator of the immune system will also be summarized. It has recently become evident that although several lines of evidence have documented abnormal suppressor T cell functions or numbers in the atopic state, the exact mechanism, however, is not clear yet. It would be important to assess whether the disturbed T cell activity is primary or secondary to the other findings in the atopic diathesis.