An immunomodulator, also known as an immunotherapy

Immunotherapy

Immunotherapy is a medical term defined as the "treatment of disease by inducing, enhancing, or suppressing an immune response". Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies. While immunotherapies that reduce or suppress are...

 is a substance (e. g. a drug

Medication

A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...

) which has an effect on the immune system

Immune system

An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

.

Immunosuppressants

Inhibits immune response in organ transplantation and autoimmune diseases.

Immunostimulants

Increase the immune response, useful in infections, immunodeficiency (for example, AIDS) and cancers.

Immunosuppressant drugs

These drugs have major role in organ transplantation and auto immune diseases. The drugs are:

1. Calcineurin inhibitors (Specific T-cell inhibitors). Cyclosporine (Ciclosporin), Tacrolimus

Tacrolimus

Tacrolimus is an immunosuppressive drug that is mainly used after allogeneic organ transplant to reduce the activity of the patient's immune system and so lower the risk of organ rejection...

2. Antiproliferative drugs (Cytotoxic drugs). Azathioprine

Azathioprine

Azathioprine is a purine analogue immunosuppressive drug. It is used to prevent organ rejection following organ transplantation and to treat a vast array of autoimmune diseases, including rheumatoid arthritis, pemphigus, inflammatory bowel disease , multiple sclerosis, autoimmune hepatitis, atopic...

, Cyclophosphamide

Cyclophosphamide

Cyclophosphamide , also known as cytophosphane, is a nitrogen mustard alkylating agent, from the oxazophorines group....

, Methotrexate

Methotrexate

Methotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Methotrexate...

, Chlorambucil

Chlorambucil

Chlorambucil is a chemotherapy drug that has been mainly used in the treatment of chronic lymphocytic leukemia...

, Mycophenolate mofetil

Mycophenolate mofetil

Mycophenolate mofetil is an immunosuppressant and prodrug of mycophenolic acid, used extensively in transplant medicine. It is a reversible inhibitor of inosine monophosphate dehydrogenase in purine biosynthesis, which is necessary for the growth of T cells and B cells...

 (MMF)

3. Glucocorticoids. Prednisolone

Prednisolone

Prednisolone is the active metabolite of prednisone, which is also used as a drug.-Uses:Prednisolone is a corticosteroid drug with predominant glucocorticoid and low mineralocorticoid activity, making it useful for the treatment of a wide range of inflammatory and auto-immune conditions such as...

 and others

4. Antibodies. Muromonab CD3, Antithymocyte globin (ATG), Rho (D) immuneglobin, Efalizumab

Efalizumab

Efalizumab is a formerly available medication designed to treat autoimmune diseases, origianally marketed to treat psoriasis. As implied by the suffix -zumab, it is a recombinant humanized monoclonal antibody administered once weekly by subcutaneous injection...

Immunostimulant drugs

They stimulate the immune system to fight against immunodeficiencies (like AIDS), infections and cancers.

1. Levamisole

Levamisole

Levamisole is an anthelminthic and immunomodulator belonging to a class of synthetic imidazothiazole derivatives. It was discovered at Janssen Pharmaceutica in 1966...

. An antihelmintic drug that also restores functions of B lymphocytes, T lymphocytes, monocytes and macrophages. Hence it has been used in colon cancer along with 5-FU.

2. Thalidomide

Thalidomide

Thalidomide was introduced as a sedative drug in the late 1950s that was typically used to cure morning sickness. In 1961, it was withdrawn due to teratogenicity and neuropathy. There is now a growing clinical interest in thalidomide, and it is introduced as an immunomodulatory agent used...

. Different effects of this old drug have been utilized in conditions such as:

• Erythema nodosum leprosum: Anti-inflammatory effect
• Multiple myleoma: Anti-angiogenesis
• Rheumatoid arthritis: Anti TNF effect.

3. BCG

BCG

BCG can stand for:Medicine*Bacillus Calmette-Guérin, a vaccine for tuberculosis*Ballistocardiography, a vital sign caused by the mechanical movement of the heart which can be recorded from the surface of the bodyBusiness...

. Used in carcinoma bladder.

4. Recombinant cytokines.

• Interferons: In tumors and chronic hepatitis B and C
• Interleukin 2 (aldeslukin): has been used in renal cell carcinoma and melanoma

Tolerogens

Induces tolerance and makes the tissue non-responsive to antigen. Tolerance is the state of non-responsiveness to antigen. The agents used as tolerogens are:

1. Costimulatory blockade. For activation, T lymphocytes need agonist specific signal from interaction of molecules such as CD28 on T lymphocytes and CD80 and CD86 on agonist presenting cell. Inhibition of this costimulatory signal can induce tolerance. Recombinant fusion protein molecules, anti CD50 MAB and anti CD56 MAB are acting by this mechanism.

2. Doner cell chimerism. Chimerism means the coexistence of two genetic lineages in a single individual. Immune functions of an individual are suppressed then a new source of immune functions like bone marrow is transfused. When it start functions, it does not recognize the antigen.

3. Soluble HLA. Human leukocyte antigen, induces tolerance through blood.
Most drugs however do not have effects on only one receptor, so an immunomodulator may be at the same time an immunosuppressant and an immunostimulant, on different targets within the immune system.

Products that are not single chemical entities, such as herbal extracts and impure products, may have even greater plurality of effect. Many species of plants, depending on the specific extraction conditions used, have immunomodulatory effects.