General Anesthetics and the Immune System

This section provides a discussion of the pharmacology of the varions agents that directly affect the immnne system. It emphasizes their mechanism of action with a brief description of their therapentic uses. More detailed information on then-pharmacology can be found in Goodman and Gilman s The Pharmacological Basis of Therapeutics (Brunton et al, 2006). Immunopharmacologics can be divided into two major areas, the immunostimnlants and the immunosuppressives. 

Interferons were first characterized as antiviral proteins produced by host cells. Later it was found that interferons had antiproliferative activity and also served as modnlating agents for macrophages and natural killer cells. 

IL-2 is a lymphokine produced by activated helper T-lympho-cytes. It induces the proliferation of T cells and promotes the differentiation of lymphocytes into cytotoxic cells. IL-2 also induces interferon gamma production (Lewko and Oldham, 2003). Activation of peripheral leukocytes with the drug produces lymphokine-activated killer cells (LAK) that lyse a variety of tumor cells in vitro. IL-2 has been cloned in bacteria through recombinant DNA technology, thus allowing the production of large amounts. IL-2 alone or with LAK cells can cause regression of several established metastatic tumors in animals (Lewko and Oldham, 2003 Dorr, 1993). 

IL-2 has been approved for the treatment of renal cell carcinoma and also has shown good activity in malignant melanoma. Both of these tumors are refractory to chemotherapy. IL-2 has also been used investigationally, both alone and in combination with LAK cells, with chemotherapy and with other biological response modifier s (BRM s) to treat a variety of different cancers (e.g., head and neck carcinoma, colorectal cancer, central nervous system cancer etc). In addition to cancer therapy, IL-2 has been used to treat patients infected with human immunodeficiency virus and it has been used ex vivo to generate antiviral T cells which were reinfused into patients (Lewko and Oldham, 2003 Dorr, 1993). 

Since many diseases are associated with cellular immunodeficiency there is an important need for immunostimulants. They have potential use as vaccine adjuvants and for the treatment of cancer, human immunodeficiency viral infections and in certain other infections. The immunostimulating agents are probably best known at this time for their use in the treatment of cancer. When used for this purpose these drugs often act through more than one mechanism. For example, in addition to their ability to augment the immune system, they may have direct cytotoxic effects as well as being able to induce differentiation of the cancer cells. 

Immune globulin (IG) is a purified preparadon of gamma globulin. It is derived from large pools of human plasma and is comprised of four subclasses of andbocUes, approximadng the cUsd ibudon of human serum (Ballow, 2005). 

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