A reappraisal of immunoglobulin variable gene primers and its impact on assessing clonal relationships between PB B cells and BM plasma cells in AL amyloidosis.

Monoclonal tumor plasma cells as well as non-terminally differentiated B cells having a clonal relationship to the tumor cells have been detected in the peripheral blood (PB) of some multiple myeloma (MM) patients but rarely in light chain (primary systemic) amyloidosis (AL) patients. Previously, our group found these peripheral clonotypic B cells in three AL patients. Here, we report detailed analysis of a larger cohort of AL patients to validate the prior findings and to investigate the effect of this cell population on clinical outcome. Fourteen AL patients were selected from a clinical prospective trial, and the relationship between immunoglobulin light chain variable gene (V(L)) representation in PB B cells and the clonal population in the bone marrow (BM) was investigated. A clonal relationship was not detected, and the present study provides important insights into the disparity with the earlier data, including clinical history of the patients and methodological analysis.