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Diseases of heavy chains: causes, symptoms, diagnosis, treatment
Last reviewed: 23.04.2024
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[Diseases of heavy chains are plasma-cell diseases, which, as a rule, have a malignant nature. In most plasma-cell diseases, M-protein is structurally similar to a molecule of a normal antibody. In contrast, heavy chain diseases produce incomplete monoclonal immunoglobulins (true paraprotein). They consist only of heavy chain components (q or 5) without light chains. Disease of the heavy chain e is not described. Most heavy chain proteins are fragments of their normal copies with a different length of deletion; these deletions are the result of structural mutations. The clinical picture is more like a lymphoma than a multiple myeloma. The presence of heavy chain disease is suspected in patients with clinical manifestations suggesting the presence of lymphoproliferative disease.
Illness of heavy chains IgA
Illness of heavy chains of IgA is the most common disease of heavy chains and is similar to Mediterranean lymphoma or immunoproliferative disease of the small intestine.
Illness of heavy chains of IgA usually manifests itself between the ages of 10 and 30 and is geographically concentrated in the region of the Middle East. The cause may be a disturbed immune response to an infection or infection. Usually there is atrophy of villi and plasma cell infiltration of the mucosa of the jejunum and sometimes an increase in mesenteric lymph nodes. Peripheral lymph nodes, bone marrow, liver and spleen are usually not affected. There are reports of rare cases of the respiratory form of this disease. Osteolytic damage is not found.
Almost all patients have signs of diffuse abdominal lymphoma and malabsorption. The electrophoresis of whey protein is normal in half the cases; often there is an increase in a 2- and b-fractions or a decrease in the f-fraction. For the diagnosis is necessary to determine the monoclonal chain in electrophoresis with immunofixation. This chain is sometimes detected in the urine concentrate. If blood and urine can not be detected, a biopsy should be performed. An abnormal protein can sometimes be found in the intestinal secret. Intestinal infiltration can be pleomorphic and have no clear signs of malignancy. Bence-Jones protein is absent.
The course of the disease can be different. Some patients die within 1-2 years, while others for many years live in a state of remission, especially after treatment with glucocorticoids, cytostatic drugs and broad-spectrum antibiotics.
Illness of heavy chains IgG
Illness of heavy chains IgG usually has a resemblance to aggressive malignant lymphoma, but sometimes it is asymptomatic and benign.
Illness of heavy chains IgG occurs mainly in elderly men, but can develop in children. Associated chronic diseases are rheumatoid arthritis, Sjogren's syndrome, systemic lupus erythematosus, tuberculosis, myasthenia gravis, hypereosinophilic syndrome, autoimmune hemolytic anemia and thyroiditis. There is a decrease in the level of normal immunoglobulins. Latic changes in bones are not characteristic. Sometimes amyloidosis develops. Common clinical manifestations are lymphadenopathy, hepatosplenomegaly, fever, recurrent infections. Edema of the palate is present in 1/4 of patients.
In the analysis of blood there is anemia, leukopenia, thrombocytopenia, eosinophilia, circulating atypical lymphocytes and plasma cells. To diagnose it is necessary to identify fragments of free monoclonal heavy chains of IgG in blood serum and urine using the immunofixation method. About 1/2 patients have a monoclonal serum component greater than 1 g / dL (often broad and heterogeneous) and 1/2 / of patients have proteinuria greater than 1 g / 24 hours. Although heavy chain proteins can include any subclass of IgG, the most common subclass of G3 is. In the absence of sufficient data for the diagnosis, a bone marrow or lymph node biopsy is performed, which reveals a variable histopathological picture.
The median survival rate for an aggressive disease is about 1 year. Lethal outcomes are usually the result of a bacterial infection or the progression of the disease. Alkylating drugs, vincristine, glucocorticoids and radiotherapy can lead to a temporary remission.
Illness of heavy chains IgM
Illness of heavy chains of IgM is rare and has a clinical picture similar to chronic lymphocytic leukemia or other lymphoproliferative diseases.
Illness of heavy chains of IgM more often affects people over the age of 50 years. Characteristic of lesions of visceral organs (spleen, liver, abdominal lymph nodes), but there is usually no marked peripheral lymphadenopathy. There are pathological fractures and amyloidosis. Whey protein electrophoresis is usually within normal limits or demonstrates hypogammaglobulinemia. Proteinuria Bence-Jones (type k) is present in 10-15% of patients. For the diagnosis, it is necessary to study the bone marrow, where one-third of patients have vacuolated plasma cells, which is a characteristic sign of the disease. Life expectancy ranges from several months to many years. The most common cause of death is uncontrolled proliferation of leukemia cells. Treatment consists of the use of alkylating agents and glucocorticoids, or it can be similar to treating a lymphoproliferative disease with which this pathology has the greatest similarity.