Clonotypic Light Chain Peptides Identified for Monitoring Minimal Residual Disease in XXXX Without @entity236 .

@entity1 @entity10805 @entity41 @entity1582 @entity236 @entity15 @entity214
BACKGROUND: Analytically sensitive techniques for measuring @entity41 ( @entity41 ) in @entity1582 ( @entity1582 ) currently require invasive and costly bone @entity236 . These methods include immunohistochemistry (IHC), flow cytometry, quantitative PCR, and next-generation sequencing. An ideal @entity1582 @entity41 test would be a serum-based test sensitive enough to detect low concentrations of Ig secreted from multifocal lesions. METHODS: Patient serum with abundant @entity10805 before treatment was separated on a 1-dimensional @entity214 -PAGE gel, and the Ig light-chain (LC) band was excised, trypsin digested, and analyzed on a Q Exactive mass spectrometer by LC- @entity15 / @entity15 . We used the peptide's abundance and sequence to identify tryptic peptides that mapped to complementary determining regions of Ig LCs. The clonotypic target tryptic peptides were used to monitor @entity41 in subsequent serum samples with prior affinity enrichment. RESULTS: Sixty-two @entity1 were tested, 20 with no detectable disease by IHC and 42 with no detectable disease by 6-color flow cytometry. A target peptide that could be monitored was identified in 57 @entity1 (91%). Of these 57, detectable disease by LC- @entity15 / @entity15 was found in 52 (91%). CONCLUSIONS: The ability to use LC- @entity15 / @entity15 to measure disease in @entity1 who are negative by bone marrow-based methodologies indicates that a serum-based approach has more analytical sensitivity and may be useful for measuring deeper responses to @entity1582 treatment. The method requires no bone @entity236 .
