43
OCTOBER 16-18, 2011 • PORTLAND, OR
P7
Hematogone light chain bias in lymphoma staging
bone marrows can mimic involvement by non-
Hodgkin lymphoma
Pramoda Challagundla, Sa A Wang, Cynthia J Swett,
Linda C Powers, Jeffrey L Jorgensen
UT MD Anderson Cancer Center, Houston, TX, USA
Background:
Various studies have described light
chain restriction in germinal center B cells in reactive
lymphoid hyperplasia, autoimmune diseases, and
HIV. We have observed occasional cases with light
chain bias in CD10+ B-cells, in bone marrow (BM)
submitted for staging of non-Hodgkin lymphoma
(NHL), suggestive of involvement by lymphoma.
However, detailed characterization using multiple
additional markers showed a phenotype consistent
with benign B cell precursors (hematogones, HGs).
Methods:
Study group includes 11 BMs with a history
of various B-cell neoplasms and was categorized
into two types: with and without concurrent residual
lymphoma, as shown in table 1. The staining panel
included monoclonal antibodies against CD5, CD10,
CD19, CD20, CD22, CD38, CD43, CD45, CD200,
Kappa and Lambda (BD Biosciences, San Jose, CA).
Data were acquired on FACS Canto II cytometers (BD
Biosciences), and analyzed using FlowJo (Treestar,
Ashland, OR). Kappa/Lambda (K/L) ratios were
determined for HGs (CD19+/CD10+), and mature B
cells (CD19+/CD10-). The remaining markers were
used to characterize HGs, and mature benign and
neoplastic B-cells.
Results:
HGs in all cases showed
a characteristic phenotype: CD5 negative, positive for
CD10, CD19, and CD20 variable, CD22 dim, CD38
bright, CD43, CD45 dim, and CD200. All NHL but one
were CD5+CD10- or CD5-CD10- (Table 1). Four of
11 cases showed the opposite light chain expression
in NHL vs. hematogones.
Conclusions:
In rare
cases, HGs can show a marked bias in light chain
expression. Familiarity with the characteristic pattern
of antigen expression on HGs can help to avoid false
positive diagnoses of NHL.
POSTER ABSTRACTS