Mu chain disease, also known as heavy chain disease or Franklin's disease, is a rare immune disorder characterized by the excessive production of abnormal immunoglobulin mu heavy chains (IgM) by plasma cells. This condition primarily affects B cells, which are responsible for producing antibodies in the immune system.
In individuals with mu chain disease, there is a genetic or acquired defect in the production of immunoglobulin chains, leading to the formation of abnormal IgM molecules. These abnormal heavy chains prevent the normal assembly of complete immunoglobulin molecules and impair the immune system's ability to fight infections. As a result, affected individuals often experience recurrent bacterial infections, particularly in the respiratory and gastrointestinal tracts.
Mu chain disease may present with various symptoms, including weakness, fatigue, weight loss, fever, and enlarged lymph nodes. Additionally, individuals may develop anemia, low platelet count, and an enlarged spleen, known as splenomegaly. It is important to note that this condition can also be associated with other malignancies such as lymphoma.
Diagnosis of mu chain disease involves blood tests to assess the levels of immunoglobulins. An electrophoretic pattern in the blood, known as a "spike" or "spiked gap," is commonly observed. Further diagnostic investigations may include bone marrow biopsy and molecular genetic testing to confirm the presence of abnormal mu heavy chains.
Treatment options for mu chain disease primarily involve chemotherapy and immunosuppressive medications to control the abnormal plasma cells. Stem cell transplantation may be considered in more severe cases. Individuals with mu chain disease require close monitoring and regular follow-ups to manage infections and address any complications that may arise.
