Type I hypersensitivities require which of the following initial priming events to occur?

sensitization

secondary immune response

cellular trauma

degranulation

Sensitization.

Explanation:

Hypersensitive reaction may be defined as the exaggerated or hyper response of the immune system. Hypersensitive reactions can occur due to auto immunity and allergies.

Type I hypersensitive reaction is mainly mediated by IgE antibodies. The sensitization towards particular stimuli like pollen grains may exaggerate the Type I hypersensitive reaction.

Thus, the correct answer is option (1).