Paradoxical Reactions to Targeted Biological Treatments: A Way to Treat and Trigger?

New targeted therapies offer the possibility of blocking a specific biological activity underlying the primary pathological condition (1). However, the target may be involved in multiple complex immunological pathways, resulting in an unexpected response and/or onset of severe adverse events that may be at odds with the therapeutic goal (1).We describe here four patients who developed con-tradictory reactions during treatment with biologicals. Their reactions lead us to ask: is it possible to treat and trigger at the same time?CASe reporTS