Gammopathies in Dogs
The body sometimes produces too many antibodies (immunoglobulins). Gammopathies are conditions in which there is a dramatic rise in the production of the antibodies. There are 2 general types. In polyclonal gammopathies, levels of all the major immunoglobulins are increased. In monoclonal gammopathies, the levels of only a single type of immunoglobulin are increased.
Polyclonal gammopathies may occur when a dog has longterm skin disease or longterm viral, bacterial, or fungal infections. Some longterm parasitic infections, rickettsial diseases, and immunologic diseases (for example, rheumatoid arthritis) may also cause polyclonal gammopathies.
Monoclonal gammopathies may be either benign and associated with no known cause or potentially associated with immunoglobulin-secreting cancers. Doberman Pinschers are predisposed to monoclonal gammopathies. The signs of monoclonal gammopathies vary depending on the location and severity of the source tumor(s). For example, tumors frequently develop in the cavities of flat bones in the skull, ribs, and pelvis and in the spinal cord. Fractures of diseased bones can lead to central nervous system problems, spinal disorders, pain, and lameness. Signs can also be caused by the presence of the monoclonal antibodies themselves. In about 20% of dogs with monoclonal gammopathies, blood changes occur that can cause blood clots, bleeding problems, depression, blindness, and other nervous system signs. In some conditions, the animals develop gangrene and lose portions of the ear tips, eyelids, toes, or tail tip.
The tumors that produce immunoglobulins can be treated with several medications. Remission may occur after treatment, but the overall outlook is poor and relapse is common after 6 to 12 months.