Monoclonal and polyclonal serum free light chains and clinical outcome in CLL

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BlankMonoclonal and polyclonal serum free light chains and clinical outcome in

chronic lymphocytic leukemia.

MJ Maurer, JR Cerhan, JA Katzmann, BK Link, C Allmer, CS Zent, TG Call, KG Rabe,

CA Hanson, NE Kay, SL Slager, TE Witzig, and TD Shanafelt

Blood, July 15, 2011; .

Division of Biomedical Statistics and Informatics, Department of Health Sciences

Research, Mayo Clinic, Rochester, MN, United States;

Free light chains (FLC) are the most commonly detected paraproteins in chronic

lymphocytic leukemia (CLL). We examined the types of FLC abnormalities and

prognostic utility of the FLC assay compared to standard prognostic biomarkers

in a prospective cohort of 339 newly diagnosed CLL patients. Three types of FLC

abnormalities were identified: monoclonal elevated FLC (elevated ? and/or ? with

abnormal FLC ratio), polyclonal elevated FLC (elevated ? and/or ? with normal

FLC ratio), and ratio-only FLC abnormality (normal range ? and ? with abnormal

FLC ratio). One hundred sixty-five (49%) patients had a FLC abnormality with

approximately equal distribution between monoclonal elevation, polyclonal

elevation, and ratio-only abnormality. All FLC abnormalities were associated

with poor time to first treatment: monoclonal FLC (HR=4.99,95% CI:(2.94-8.48)),

polyclonal FLC (HR=2.40, 95%CI (1.24-4.64)), ratio-only FLC (HR=2.57,95%

CI:(1.40-4.69)). Monoclonal FLC and polyclonal FLC were associated with poor

overall survival compared to patients with normal FLC. Results remained

significant after adjusting for Rai stage. The prognostic ability of FLC

compared favorably to established CLL prognostic parameters (e.g. IGHV, ZAP70,

FISH). The FLC assay is a simple, widely available clinical test with similar

prognostic utility as routinely used prognostic biomarkers for CLL. Among

individuals with FLC abnormalities, the type of abnormality impacts prognostic

significance.

PMID: 21765023