Monoclonal Immunoglobulin (Ig), Monoclonal antibody, Immunofixation Electrophoresis (IFE)
- IFE (Immunofixation electrophoresis) can be done on the serum of the patient.
- 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.
- 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
- To identify the monoclonal gammopathy.
- To monitor the treatment with monoclonal gammopathy.
- To find the light chains / heavy chain of immunoglobulin in the urine.
- Monoclonal gammopathy of undetermined significance (MGUS)
- Waldenstrom’s macroglobulinemia.
- Multiple Myeloma (used more than 100 years).
- Immunofixation electrophoresis is the study of protein antigens, and their split products and evaluation of myeloma.
- This was described in 1964.
- Immunofixation electrophoresis is replacing the 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 binds to surface antigen.
- The production of the monoclonal antibodies in the animals takes 3 to 6 months.
- IFE identify the monoclonal Ig and also identify light chain 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% in people over the age of 75 years of age.
- These are lower in the 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 sample of the patient is placed in six separate wells on the agarose gel and their major protein group is separated by electrophoresis.
- One of this track 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 visualized the fixed proteins bands.
- 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, 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 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.