DTH reactions may include, but are not limited to, contact dermatitis (eg, poison ivy rash), tuberculin skin test reactions, granulomatous inflammation (eg, sarcoidosis, Crohn disease), allograft rejection, graft versus host disease, and autoimmune hypersensitivity reactions.
tricks of the trade. 1  Clever ways of operating a business or performing a task or activity, especially slightly dishonest or unfair ones. For example, Alma knows all the tricks of the trade, cutting the fabric as close as possible, or The butcher weighs meat after it's wrapped; charging for the packaging is one of the tricks of the trade.
voluntary trade. A term used to describe the foundation of the present economic system. When products and goods are exchanged for other products or services, the result is a trade. Voluntary trade describes a market where buyers and sellers have the right to sell and buy by their own preference or refuse to if they so choose. Voluntary trade also describes a person's freedom to choose to work for compensation versus being forced into labor.