<prompt> Which one of the following is FalseTheobald - smith phenomenon is a type I hypersensitivity reactionSerum sickness is a type II hypersensitivity reactionAllograft rejection is a type IV hypersensitivity reactionTransfusion reaction is a type II hypersensitivity reaction  <response>: Option 2 1. Serum sickness is a systemic inflammatory reaction caused by deposition of immune complexes at many sites of the body. The condition manifests after a single injection of a high concentration of foreign serum. It appears a few days to 2 weeks after injection of foreign serum or ceain drugs, such as penicillin. However, serum sickness is considered as an immediate hypersensitivity reaction, because symptoms appear immediately after formation of immune complex. 2. Systemic Serum sickness is a type III hypersensitivity reaction not type II Option 1 Experiments to demonstrate type I hypersensitivity reaction: P-K reaction, Schultz Dale phenomenon and Theobald smith phenomenon Option 3 Noninfectious conditions of HSR IV: Diabetes mellitus type 1 Multiple sclerosis Chronic transplant rejection Graft-versus-host disease Option 4 Transfusion reactionABO incompatibility: type-II reactions by By complement dependent cytolysis due to MAC, inflammation by C5a, C3a, opsonization by C3b and C4b. 