Examinations
Examinations
General Information:
Lambda light chains are components of immunoglobulins (antibodies), which are proteins with antigen-binding activity. Immunoglobulins are produced by plasma cells, which are derived from precursor B-lymphocytes in the bone marrow. They differ structurally and functionally and are divided into five classes: IgG, IgA, IgM, IgD, and IgE, with several subclasses. Polyclonal increases in immunoglobulins are a normal response to infections.
Monoclonal gammopathies occur when an abnormal amount of immunoglobulin is produced by plasma cells or B-lymphocytes originating from a single clone. These conditions can indicate benign or malignant diseases. Monoclonal gammopathy is detected by the presence of an abnormal band during electrophoresis of serum or urine proteins.
Immunoglobulin molecules consist of two identical heavy chains and two identical light chains (either kappa or lambda). The type of heavy chain determines the immunoglobulin class. Light chains are characterized by constant and variable regions, with the variable region determining antigen specificity.
Monoclonal immunoglobulins produced by clonal cells have identical heavy and light chains. In electrophoresis, a high level of monoclonal immunoglobulin appears as a sharp, dense band (M-peak or paraprotein) in the gamma-globulin region. Monoclonal immunoglobulins may exist as polymers, monomers, or fragments (light or heavy chains).
Free light chains pass through the renal filter and can be detected in urine using electrophoresis.
Detection of monoclonal paraproteins is based on protein electrophoresis. Sometimes fibrinogen or CRP may be mistaken for paraproteins in the beta- or gamma-fractions. Confirmation involves immunofixation using specific polyvalent antisera targeting immunoglobulins. Quantitative analysis of paraproteins is performed via densitometry. Full identification (typing) requires electrophoresis and immunofixation with an extended panel of antisera against IgG, IgA, IgM, kappa, and lambda chains.
In diagnosis and prognosis, the paraprotein class, concentration at diagnosis, and its progression over time are critical. The presence of paraproteins is a hallmark of various hematological malignancies.
- Avoid alcohol for 24 hours before the test.
- Children under 1 year should not eat for 30–40 minutes before the test.
- Do not eat for 4 hours before the test; drinking non-carbonated water is allowed.
- Avoid physical and emotional stress for 30 minutes before the test.
- Do not smoke for 30 minutes before the test.
- Initial evaluation alongside serum protein electrophoresis and immunofixation in suspected monoclonal gammopathy (this test may replace urine electrophoresis for certain diagnostic purposes, except for AL amyloidosis).
- Prognosis, risk assessment, and monitoring in patients with:
- Multiple myeloma.
- Solitary plasmacytoma.
- Non-secretory myeloma.
- Monoclonal gammopathy of undetermined significance (MGUS).
- AL amyloidosis.
- Screening nephrotoxic levels of free kappa light chains for early detection of myeloma kidney.
Detection of Paraproteins:
Benign Conditions:
- Transient paraproteinemia.
- Monoclonal gammopathy of undetermined significance (MGUS).
Malignant Conditions:
- Multiple myeloma.
- Waldenström’s macroglobulinemia.
- Lymphoma or chronic lymphocytic leukemia (CLL).
- Heavy chain disease.
- Paraproteinemic polyneuropathy.
- Cryoglobulinemia.
- Cold hemolytic anemia.
- AL amyloidosis or chain collapse disease.
- POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, Skin changes).