Gammopathies in Dogs

Antibodies, also referred to as immunoglobulins, are produced to protect the body from threats. Increases in the amount of immunoglobulins in the blood are usually indicative of an underlying illness. Quite often these illnesses are chronic, particularly in the case of polyclonal gammopathies. The overabundance of antibodies in the system can cause additional problems, such as hyperviscosity syndrome, a syndrome in which the protein concentrations in the blood are too high, causing thickened blood and reduced blood flow.

Immunoglobulin production that has taken an abnormal turn may indicate the development of inflammatory conditions such as arthritis. In addition, health issues like lymphoma may result in increased levels of gammopathies the blood of your canine.

The symptoms associated with gammopathies in dogs can be as varied as the diseases and disorders that spur them. One of the more common causes of gammopathy in dogs is an uncommon cancer of the plasma cells called multiple myelomas. The symptoms of multiple myelomas can include: 

• Bleeding from nose or gums
• Bone pain
• Excessive thirst
• Excessive urination
• Eye dysfunction
• Lameness 
• Lethargy
• Seizures
• Weakness

Types

Immunoglobulins, also known as antibodies, are made by the immune system in response to a threat or perceived threat to the body. There are four main classes of immunoglobulins recognized in canines.

• IgA works primarily to protect the surfaces of the body from superficial invaders, it is found on the skin and mucous membranes 
• IgE antibodies are found on the skin and mucous membranes and in the lungs; they respond to foreign invaders like pollen, animal dander, and are the antibodies that are most responsible for allergic reactions 
• IgG is the smallest but most common antibody in the system and can be found in all bodily fluids; they are essential in fighting both bacterial and viral infections and are the only type of immunoglobulin small enough to cross the placental barrier
• IgM immunoglobulins can be found in the blood and in the lymph fluid; they are the largest of the antibodies in the system and are often the first produced when an infection strikes

Monoclonal gammopathies

Monoclonal gammopathies are characterized by an increase in a single immunoglobulin class. These increases may occur without any underlying cause, but they are more often related to a myeloma, a type of tumor that originates in the plasma cells and secretes antibodies. Other disorders which are known to increase specific immunoglobulin classes include leishmaniasis and ehrlichiosis.

Polyclonal gammopathies

With polyclonal gammopathies, immunoglobulin levels increase across all of the immunoglobulin classes at once. The overall increase of antibodies is usually instigated by chronic infections, abscesses, and infestations.

When you bring your pet into the veterinary clinic, a complete physical examination is likely to be completed to determine the overall health of the patient and to look for any trouble spots, such as enlarged organs, lumps, or excessive pain. A standard urinalysis will generally reveal that there is an abnormally high level of proteins and the chain fragments from the antibodies will appear in the urine. General blood tests such as a complete blood count and a biochemical profile will also be evaluated. The veterinary technician may see very different results depending on the underlying cause of the disorder, but in nearly all cases of gammopathy the total protein and globulin levels will show as elevated, and the CBC will often show scores of plasmas and white blood cells with a reduction in the volume of red blood cells. 

This can cause hyperviscosity, a condition in which the blood is unable to flow freely due to the thickening of the blood. When the increase in proteins, specifically the globulins, the veterinarian is likely to request additional testing to determine which class or classes of antibody is showing the increase. There are several types of tests available to detect the amount and type of immunoglobulin present including quantitative tests and serum tests for immunoglobulin, and protein electrophoresis.

Overall treatment of this disorder is the treatment of the underlying disease, which can be different from patient to patient. Animals that are in crisis for any reason will be given general supportive treatments such as IV fluids and electrolytes to prevent dehydration and will include oxygen as well if your pet is having difficulty breathing or is showing low oxygen levels in the blood. If hyperviscosity is present, and IV fluid therapy is not sufficient to improve the viscosity of the blood, plasmapheresis is the treatment of choice. 

Plasmapheresis is a medical procedure in which blood is removed from the system, treated, and then returned back to the body. Although this is generally a well-tolerated procedure, there are some minor risks involved with this therapy. When the blood is being treated by going through the plasmapheresis machine, it can clot, and small amounts of sodium citrate are added to the blood to help prevent this by binding to the calcium in the blood, which can lead to dangerously low calcium levels if intravenous calcium is not provided during the procedure. Other complications could include lowered blood pressure, transfusion reactions, suppression of the immune system, or bleeding from the large intravenous catheter.

A large percentage of dogs who develop gammopathies have an underlying condition known as multiple myelomas. Multiple myelomas are characterized by tumors that have been formed from plasma cells.This is a serious disorder and can lead to vision impairment, a detachment of the retina, systemic infections, and if left untreated, may lead to lymphosarcoma. Cancers such as multiple myelomas are generally treated with chemotherapy for canines. Complications from chemotherapy can occur, so regular checks of your dog’s liver and kidney enzyme levels will be required. Dogs are often sent home the day of the chemotherapy treatments.

Most of the drug is metabolized within just a few hours, however, some remnants of it may remain in the blood for a few days. It is important to use gloves when dealing with bodily fluids and maintain good hand washing hygiene. Children, pregnant and nursing women, and immunocompromised adults should avoid contact with the bodily fluids during that time.