Detection and Characterization of Paraproteinemia in Canine Chronic B-cell Lymphocytic Leukemia Using Routine and...

Area of Science:

• Veterinary Hematology
• Canine Oncology
• Immunoglobulin Analysis

Background:

• Hyperglobulinemia occurs in 26% of canine chronic B-cell lymphocytic leukemia (B-CLL) cases.
• Monoclonal protein (M-protein) incidence in B-CLL is poorly understood using protein electrophoresis and immunofixation (IF).

Purpose of the Study:

• Determine the proportion of canine B-CLL cases with M-protein using plasma protein electrophoresis (PPE) and routine/free light chain (fLC) IF.
• Assess MUM1/IRF4 expression in productive B-CLL cases via cell tube block (CTB).

Main Methods:

• Analyzed 48 canine B-CLL plasma samples using PPE and routine/fLC IF.
• Diagnosed B-CLL via peripheral blood flow cytometry.
• Performed CTB on 15 additional patients.

Main Results:

• M-protein detected in 67% (32/48) of B-CLL cases; hyperproteinemia present in 35% (17/48).
• IgM was the most common isotype; a subset had detectable fLCs.
• PAX5 was consistently expressed, MUM1/IRF4 was not; CD21+ cell counts higher with detectable M-protein.

Conclusions:

• The majority of canine B-CLL cases exhibit an M-protein, frequently IgM, irrespective of hyperproteinemia.
• A significant subset of cases presented with detectable free light chains (fLCs).
• Prognostic implications of heavy and fLC presence warrant further investigation.