Monoclonal Immunoglobulin (Ig)

Sample Monoclonal Immunoglobulin (Ig)

1. IFE (Immunofixation electrophoresis) can be done on the patient’s serum.
2. Other fluids are CSF, urine, and biological fluids.
3. 24 hours of urine is collected according to the instructions.
4. Can store the sample at 2 to 8 °C for 5 days.

Precautions for Monoclonal Immunoglobulin (Ig)

1. The fresh serum is the choice of sample.
2. The fasting sample is preferred.
3. Avoid anticoagulant use.
4. Centrifuge the sample immediately for 15 minutes.

Purpose of the test for Monoclonal Immunoglobulin (Ig)

1. To identify the monoclonal gammopathy.
2. To monitor the treatment with monoclonal gammopathy.
3. To find the light chains / heavy chains of immunoglobulin in the urine.
4. Monoclonal gammopathy of undetermined significance (MGUS)
5. Waldenstrom’s macroglobulinemia.
6. Multiple Myeloma (used more than 100 years).
7. Amyloidosis.

Definition of monoclonal immunoglobulin(Ig):

1. It is a so-called monoclonal gammopathy spike like M-protein and paraprotein.
2. It is located in the γ-region and less frequently in the β-area. Rarely seen in the α-region.
3. The majority of people with monoclonal spikes are myeloma patients.
4. Other minorities with monoclonal gammopathy are:
   1. Walden’s storm macroglobulinemia.
   2. Secondary monoclonal gammopathy.
   3. Idiopathic monoclonal gammopathy.

Definition of monoclonal gammopathy:

1. These monoclonal gammopathies are a clonal disorder of B-lymphocyte proliferation.
2. These atypical B-lymphocytes are single clones of the proliferating cells that will produce single immunoglobulin (Ig) or its fragments.
3. This abnormal monoclonal immunoglobulin (Ig) is present in the serum, CSF, and urine.

Pathophysiology of Monoclonal Immunoglobulin (Ig)

1. Immunofixation electrophoresis studies will differentiate protein antigens and their split products and the evaluation of myeloma.
   1. This was described in 1964.
   2. Immunofixation electrophoresis is replacing electrophoresis because of its rapidity and ease of interpretation.
   3. The principle is the same in both processes.
2. Monoclonal immunoglobulin (Ig) consists of heavy and light chains.
   1. These are purified antibodies cloned from a single cell.
   2. These antibodies will bind to surface antigens.
   3. The production of the monoclonal antibodies in the animals takes 3 to 6 months.
3. Only heavy chains are produced in heavy chain diseases, while in light chain diseases, only light chains are produced.
4. IFE identifies the monoclonal Ig and also identifies light chains or heavy chains.
5. By electrophoresis, there is a spike of monoclonal Ig (Antibody).

6. Waldenstrom’s macroglobulinemia also shows a monoclonal spike.
   1. Above both diseases give light chains excretion in the urine.
   2. IFE can also find that the spike is due to a light chain or heavy chain.
7. Chronic diseases give rise to polyclonal bands of these immunoglobulins.
8. Non-malignant monoclonal immunoglobulin seen in:
   1. 5% of people over the age of 75 years of age.
   2. These are lower in concentration than the malignant bands.

Procedure and Principle of Immunofixation electrophoresis (IFE)

1. This IFE is a two-stage procedure:
   1. Agarose gel protein electrophoresis (IEF)
   2. Immunoprecipitation.
2. The patient’s sample is placed in six separate wells on the agarose gel, and their major protein group is separated by electrophoresis.
3. 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.
4. The other five tracks are treated with heavy and light chains antisera which react with individual immunoglobulins in the specimen, causing them to Immuno-
5. fix in the agarose.
6. All unreacted proteins are washed from those five tracks out of the gel.
7. 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:

1. Multiple myelomas show in 99 % of the patients in serum and urine.
2. Waldenstrom macroglobulinemia always shows a serum IgM-type monoclonal band.
3. Monoclonal light chains also called κ or Bence Jones protein, are seen in the urine of Multiple myeloma cases in 75 % of the patients.
4. Waldenstrom macroglobulinemia also shows light chains in the urine in 75 % of the patients.
5. Amyloidosis can see in the light chain or heavy chain in the urine.

Multiple Myeloma signs and symptoms are:

1. Weakness and fatigue.
2. Weakness in the legs.
3. Nausea and vomiting.
4. Recurrent infections.
5. Bone pain in the back or ribs.
6. H/O fracture

Polyclonal bands of Ig are seen in:

1. Chronic infections.
2. Autoimmune diseases.
3. Chronic liver diseases.
4. Amyloidosis.

Monoclonal Ig is seen in urine:

1. Multiple myelomas.
2. Waldenstrom macroglobulinemia.

Diagnostic criteria for monoclonal gammopathy:

1. Bone marrow plasma cells are >10% of the total cells.
2. Monoclonal protein in the serum or urine.
3. Evidence of end organs diseases like:
   1. Anemia.
   2. Bone lesions.
   3. Hypercalcemia.
   4. Renal diseases.

---