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The following is a summary of “Immunoglobulin heavy/light chain assay in the diagnosis, monitoring and follow-up of renal AL amyloidosis patients at different disease stages,” published in the April 2025 issue of Annals of Hematology by Wang et al. 

Immunoglobulin light chain (AL) amyloidosis is a rare plasma cell disorder with high rates of misdiagnosis and mortality. Standard assays such as serum immunofixation electrophoresis (IFE) and serum free light chain (FLC) often fail to detect low M protein levels, especially with renal decline. 

Researchers conducted a retrospective study to assess the underexplored role of the heavy/light chain (HLC) assay in AL amyloidosis, where standard tests often miss low M protein levels. 

They evaluated the value of HLC assay in patients with AL amyloidosis at different disease stages and compared it to IFE and FLC assay performance. 

The results showed 34/40 (85%) untreated patients were IFE and free light chain ratio (FLCr) positive, and 31 (78%) had abnormal heavy light chain ratio (HLCr). Among 67 samples from 44 treated patients, 57 (85%) were IFE positive, 9 (13%) had abnormal FLCr, and 45 (67%) had abnormal HLCr. Abnormal HLCr was seen in 1/7 (14%) CR, 17/25 (68%) very good partial response (VGPR), 9/11 (82%) partial response (PR), and 6/8 (75%) patients in no response (NR). 

Investigators identified the potential value of the HLC assay in detecting M proteins and monitoring response and serologic residual disease. 

Source: link.springer.com/article/10.1007/s00277-025-06345-7