Monoclonal Immunoglobulin (Ig), Monoclonal antibody, Immunofixation Electrophoresis (IFE)
Monoclonal Immunoglobulin (Ig)
Sample Monoclonal Immunoglobulin (Ig)
- IFE (Immunofixation electrophoresis) can be done on the patient’s serum.
- Other fluids are CSF, urine, and biological fluids.
- 24 hours of urine is collected according to the instructions.
- Can store the sample at 2 to 8 °C for 5 days.
Precautions for Monoclonal Immunoglobulin (Ig)
- The fresh serum is the choice of sample.
- The fasting sample is preferred.
- Avoid anticoagulant use.
- Centrifuge the sample immediately for 15 minutes.
Purpose of the test for Monoclonal Immunoglobulin (Ig)
- To identify the monoclonal gammopathy.
- To monitor the treatment with monoclonal gammopathy.
- To find the light chains / heavy chains of immunoglobulin in the urine.
- Monoclonal gammopathy of undetermined significance (MGUS)
- Waldenstrom’s macroglobulinemia.
- Multiple Myeloma (used more than 100 years).
Definition of monoclonal immunoglobulin(Ig):
- It is a so-called monoclonal gammopathy spike like M-protein and paraprotein.
- It is located in the γ-region and less frequently in the β-area. Rarely seen in the α-region.
- The majority of people with monoclonal spikes are myeloma patients.
- Other minorities with monoclonal gammopathy are:
- Walden’s storm macroglobulinemia.
- Secondary monoclonal gammopathy.
- Idiopathic monoclonal gammopathy.
Definition of monoclonal gammopathy:
- These monoclonal gammopathies are a clonal disorder of B-lymphocyte proliferation.
- These atypical B-lymphocytes are single clones of the proliferating cells that will produce single immunoglobulin (Ig) or its fragments.
- This abnormal monoclonal immunoglobulin (Ig) is present in the serum, CSF, and urine.
Pathophysiology of Monoclonal Immunoglobulin (Ig)
- Immunofixation electrophoresis studies will differentiate protein antigens and their split products and the evaluation of myeloma.
- This was described in 1964.
- Immunofixation electrophoresis is replacing electrophoresis because of its rapidity and ease of interpretation.
- The principle is the same in both processes.
- Monoclonal immunoglobulin (Ig) consists of heavy and light chains.
- These are purified antibodies cloned from a single cell.
- These antibodies will bind to surface antigens.
- The production of the monoclonal antibodies in the animals takes 3 to 6 months.
- Only heavy chains are produced in heavy chain diseases, while in light chain diseases, only light chains are produced.
- IFE identifies the monoclonal Ig and also identifies light chains or heavy chains.
- By electrophoresis, there is a spike of monoclonal Ig (Antibody).
- Waldenstrom’s macroglobulinemia also shows a monoclonal spike.
- Above both diseases give light chains excretion in the urine.
- IFE can also find that the spike is due to a light chain or heavy chain.
- Chronic diseases give rise to polyclonal bands of these immunoglobulins.
- Non-malignant monoclonal immunoglobulin seen in:
- 5% of people over the age of 75 years of age.
- These are lower in concentration than the malignant bands.
Procedure and Principle of Immunofixation electrophoresis (IFE)
- This IFE is a two-stage procedure:
- Agarose gel protein electrophoresis (IEF)
- The patient’s sample is placed in six separate wells on the agarose gel, and their major protein group is separated by electrophoresis.
- One of these tracks is treated with a chemical fixation solution to fix all the proteins in agarose and create an electrophoresis reference pattern for the specimen.
- The other five tracks are treated with heavy and light chains antisera which react with individual immunoglobulins in the specimen, causing them to Immuno-
- fix in the agarose.
- All unreacted proteins are washed from those five tracks out of the gel.
- Now all 6 tracks are stained to visualize the fixed protein bands.
Normal Monoclonal Immunoglobulin (Ig)
- No monoclonal band is identified.
The monoclonal band is seen in:
- Multiple myelomas show in 99 % of the patients in serum and urine.
- Waldenstrom macroglobulinemia always shows a serum IgM-type monoclonal band.
- Monoclonal light chains also called κ or Bence Jones protein, are seen in the urine of Multiple myeloma cases in 75 % of the patients.
- Waldenstrom macroglobulinemia also shows light chains in the urine in 75 % of the patients.
- Amyloidosis can see in the light chain or heavy chain in the urine.
Multiple Myeloma signs and symptoms are:
- Weakness and fatigue.
- Weakness in the legs.
- Nausea and vomiting.
- Recurrent infections.
- Bone pain in the back or ribs.
- H/O fracture
Polyclonal bands of Ig are seen in:
- Chronic infections.
- Autoimmune diseases.
- Chronic liver diseases.
Monoclonal Ig is seen in urine:
- Multiple myelomas.
- Waldenstrom macroglobulinemia.
Diagnostic criteria for monoclonal gammopathy:
- Bone marrow plasma cells are >10% of the total cells.
- Monoclonal protein in the serum or urine.
- Evidence of end organs diseases like:
- Bone lesions.
- Renal diseases.