What Is Bence-Jones Protein?
Bence-Jones protein (BJP) is a type of protein found in the urine of some people with certain types of blood cancers, particularly multiple myeloma. It is named after the physician Henry Bence Jones, who first described it in 1847. Bence-Jones protein is a type of light chain protein that can be found in certain antibodies produced by the immune system. Antibodies are specialized molecules that target specific infections. However, in some cases, such as certain types of cancer or rare diseases, the immune system stops producing diverse antibodies and instead produces monoclonal antibodies, which are all the same type and cannot protect against a variety of infections. Bence-Jones proteins are part of one of these monoclonal antibodies. Bence-Jones proteins are typically very small and cannot be detected in urine. However, when present in large quantities in the bloodstream, they can pass through the kidneys and end up in the urine. This can lead to kidney damage, inflammation, and blockage of kidney cells.
What Is the Expected or Usual Amount of Bence-Jones Proteins Found in Urine?
The typical or expected range of Bence-Jones proteins in urine is zero or none at all. The presence of this protein in the urine usually suggests a specific medical condition, such as cancer. The level of Bence-Jones protein detected in a test can differ based on factors such as age, gender, medical history, and the specific detection method utilized by the healthcare provider. In general, a negative or normal test result indicates that there are no Bence-Jones proteins found in the urine, while a positive result suggests that these proteins are present.
What Is the Cause of an Abnormal Bence-Jones Protein Level?
An underlying medical condition that can cause unusual Bence-Jones protein levels in urine is multiple myeloma, which is a type of cancer that affects the blood cells and results in the formation of tumors within the bones. As cancer advances, it can interfere with the production of antibodies and lead to elevated levels of free Bence-Jones protein. Bence-Jones proteins are detected in the urine of around 50 percent to 80 percent of individuals with multiple myeloma.
Less common reasons for increased Bence-Jones protein levels in urine may include:
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Amyloidosis, which is characterized by the accumulation of abnormal proteins in the tissues.
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Lymphomas, a type of cancer that affects the lymphatic system, which is a vital component of the immune system.
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Waldenstrom macroglobulinemia, a rare type of cancer that falls under the category of non-Hodgkin lymphoma.
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Monoclonal gammopathy of undetermined significance (MGUS), where the plasma cells generate a higher quantity of one type of antibody than they should. This does not result in tumors and usually does not necessitate treatment when it is the only medical condition present.
What Is the Procedure to Perform a Bence-Jones Protein Test?
To perform a Bence-Jones protein test, the initial stage involves obtaining a urine sample. The specific type of sample required would depend on the testing technique chosen by the healthcare team. One approach to conducting the Bence-Jones protein test is through the 24-hour collection method, which can be performed at home. In this test, a patient begins by completely emptying the bladder in the morning without collecting a sample. Then, they collect all the urine they pass in a container provided for the next 24 hours. Alternatively, a single urine sample may be sufficient, which is usually collected at the doctor's office.
For both methods, it is important to collect clean-catch urine samples, which means that a patient needs to avoid introducing any germs from the genitals into the urine sample. The physician may provide a kit to ensure that the urine sample is uncontaminated, which includes sterile wipes and specific instructions for sample collection.
The levels of Bence-Jones protein in the urine can be analyzed using different methods by the medical team. These include:
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Strips: These can change color in the presence of Bence-Jones protein, but this is the least accurate method.
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Urine Immunofixation Electrophoresis: This method involves spreading all the proteins in the urine out in a gel and testing them for the presence and quantity of Bence-Jones protein. It is the most commonly used method.
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Free Light Chain Assay: This is the newest method for analyzing Bence-Jones protein. It compares the amount of Bence-Jones protein to the total amount of all light chain proteins in the urine.
What Additional Tests May Be Performed in Conjunction With This Test?
To diagnose multiple myeloma, doctors often perform a series of tests that may include:
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Complete blood count (CBC) to check red blood cells, white blood cells, and platelets levels in the blood.
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Chemistry profile to check levels of albumin, blood urea nitrogen, calcium, creatinine, and lactate dehydrogenase. These levels can provide information about kidney function and the extent of multiple myeloma.
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Beta-2 microglobulin and C-reactive protein tests to determine how multiple myeloma has spread.
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Quantitative immunoglobulin testing to check the levels of different types of antibodies.
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Serum protein electrophoresis (SPEP) to measure protein levels in the blood, including M protein, which is a large number of abnormal monoclonal antibodies.
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Immunofixation electrophoresis (IFE) to detect proteins from abnormal antibodies.
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Electrophoresis and immunoelectrophoresis of concentrated urine, which are other methods of detecting monoclonal protein in the urine.
What Is the Reason for Conducting This Test?
This test may be necessary if someone is experiencing any of the following symptoms:
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Bone pain or fractures, particularly in the back, hips, or skull.
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High levels of calcium in the blood.
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Reduced levels of red or white blood cells or platelets.
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Nervous system issues like pain, numbness, or weakness.
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Stroke-like symptoms such as confusion and dizziness.
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Swelling and weakness in the legs.
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Frequent infections.
What Should a Patient Do to Prepare for This Test?
There is no specific preparation needed for this test, but it is important to inform the healthcare provider about any medications, herbs, vitamins, or supplements, including those that do not require a prescription and any illicit drugs.
Conclusion
In conclusion, Bence-Jones protein is a type of protein found in the urine of some people with certain types of blood cancers, particularly multiple myeloma. The usual range of Bence-Jones protein in urine is zero, and its presence usually indicates an underlying medical condition. The Bence-Jones protein test involves collecting a urine sample and analyzing it using different methods to detect the presence and quantity of Bence-Jones protein. This test may be necessary if a person is experiencing symptoms of multiple myeloma or other conditions that can cause abnormal Bence-Jones protein levels.
