Auto-immune Disease can be broadly defined as disease caused by a defect in immune surveillance. The mechanisms of this defect development are complex and not completely understood. Under normal circumstances, the immune system is constantly protecting itself from foreign invaders (e.g., bacteria, viruses, fungi) that may lead to disease. It also is targeting abnormal cells that are not necessarily foreign such as cancer cells. It does so through a process known as immune surveillance. Each individual has markers on every cell in its body. These markers will uniquely identify the cell as “self”. When the immune system identifies an object such as a virus that does not have the proper markers, the body recognizes it as “non-self” and mounts an immune response against it. This response is aimed at destroying it and removing it from the body. Under ideal circumstances, this system is highly efficient and will eradicate the invader(s) from the body. If dealing with a virus or bacteria this is optimal.
The immune response is mediated through target specific antibodies, blood cells that directly and indirectly engage the target cell and “RE” organs. Antibodies are molecularly specific proteins created in response to the marker codes on the invader. The body makes many different series of antibodies for any given invader. Once produced, antibodies will be released into the bloodstream where they will circulate awaiting contact with its exactly matched marker. Once it encounters its marker, it will “stick” to it. Once an antibody “sticks” to a marker on a target cell, this reaction triggers an intensification of the reaction against the target.
Infectious agents such as viruses can attach to a blood cell or membrane and allow the reaction to develop. Regrettably, the body does not selectively target only the virus adherent to the blood cell or membrane, but the virus and entire blood cell or membrane. Drugs and viruses may also initiate an immune response by damaging the surface of the cells or membranes. This exposes underlying or hidden components that are not normally seen by the immune system. This exposes the immune system to a new or “foreign” protein which may act to initiate a reaction against them. Inflammatory reactions within the body may release proteins that cross react with the proteins on the surface of a cell thereby initiating the response. Cancers may function in the same manner as an inflammatory reaction creating crossover proteins or they may create antibodies themselves. Cancer may also act to modulate the immune system as a whole.
Targets for this immune dysfunction include circulating blood cells such as red blood cells, platelets and occasionally white blood cells. Other tissues such as synovial membranes in joints, components of the skin and kidney can be targets leading to severe disease states. Many other conditions are believed to be mediated by the immune system and may be treated similarly. Granulomatous meningoencephalitis and chronic active hepatitis are two severe diseases thought to be mediated by this immunologic mechanisms.
Immune diseases can be very difficult to treat. In many cases treatment is prolonged for the disease is very tenacious and persistent. Often owners think we are going to have it cured in one visit. This is never the case. In some cases, people and pets may have flare ups lifelong.