Which of the following is NOT an example of a Type 4 hypersensitivity reaction?

Type 4 hypersensitivity, also known as delayed-type hypersensitivity, involves T-cell mediated immune responses rather than antibody-mediated responses. It is characterized by the reaction that occurs several hours to days after exposure to the antigen.

Phlyctenulosis, contact dermatitis, and the tuberculin skin test (TB skin test) are classic examples of Type 4 hypersensitivity.

Phlyctenulosis occurs when there is a hypersensitivity reaction to antigens from bacteria or other irritants, leading to the formation of a small elevated lesion on the conjunctiva or cornea. This is mediated by T cells recognizing the antigens and triggering an inflammatory response.

Contact dermatitis is an inflammatory skin condition that occurs after exposure to allergens like poison ivy or nickel, which elicits a delayed reaction mediated by sensitized T cells.

The tuberculin skin test is a diagnostic tool where a small amount of purified protein derivative (PPD) is injected subcutaneously, and a delayed reaction occurs if there has been prior sensitization to Mycobacterium tuberculosis, again driven by T cells.

Rheumatic fever, however, is primarily mediated by antibody responses rather than T-cell responses, which categorizes it as an example of a