Quantification by Ultrafiltration and Immunofixation Electrophoresis Testing (QUIET) for monoclonal serum free light chains


The current state of the art:

Plasma cell myelomas is a plasma cell disorder that is associated with the presence of monoclonal immunoglobulin or fragments secreted by a B-cell clone. It can be detected and monitored by the presence of free monoclonal light chains. Currently, the serum free-light-chain (sFLC) assay is the most analytically sensitive assay on the market. It measures the ratio of free kappa (κ) and lambda (λ) light chain. The abnormal ratio (<0.26 or >1.65) indicates the presence of monoclonal proteins.


The problems with the current art:

However, sFLC measures free light chains of all varieties and is not specific for monoclonal light chains. Therefore, analytical and clinical factors that result in abnormal immunoglobulin presence would impact the sensitivity of sFLC. For example, patients treated with stem cell transplants have abnormal free light chains, a confounding factor to monitor monoclonal light chains.

The immunoenrichment coupled with MALDI-TOF can be an effective method to measure the monoclonal light chains. But it requires special reagents, equipment, and technical expertise that are not available in most clinical laboratories.


The advantages of our invention:

The scientists at AU developed a novel method, involving ultrafiltration and immunofixation electrophoresis to quantitate the concentration of monoclonal free light chains. Monoclonal light chains are differentiated from polyclonal light chains through densitometric scanning . In ten patients with light chain myelomas, the current method enables the detection of monoclonal light chains, including the patient samples that were negative by conventional immunofixation  electrophoresis. The current method can detect as low as 1.0-2.0 mg/dL of monoclonal free light chains.

Compared to immunoenrichment coupled with MALDI-TOF-MS method , the current method uses a protocol accessible to most clinical chemistry laboratories and provides a more direct test to monitor the course of free-light-chain gammopathy.


AURI # 2020-021

IP: Provisional US 62/949,901


Patent Information:
For Information, Contact:
Augusta University
Gurmukh Singh
Roni Bollag
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