Restricted kappa/lambda light chain ratio by flow cytometry in germinal center B cells in Hashimoto thyroiditis.
To determine the diagnostic significance of the kappa/lambda ratio in germinal center (GC) B cells in Hashimoto thyroiditis (HT), we used 4-color flow cytometry to immunophenotype 27 samples (21 patients) of well-characterized HT B-cell clonality was analyzed further by polymerase chain reaction (PCR) of the immunoglobulin heavy chain (IgH) and bcl-2/IgH fusion genes using DNA extracted from aspirate smears and/or paraffin-embedded tissues. By flow cytometric analysis, the CD10+ GC B cells had a higher mean +/- SD kappa/lambda ratio than the CD10- B cells (5.1 +/- 3.3 vs 2.0 +/- 0.8; P < .0001, Student t test). In 18 samples (67%), CD10+ GC B cells had a kappa/lambda ratio greater than 3.07 (the upper limit of kappa/lambda ratio reported in reactive nodes; range, 3.2-14.4 in the 18 cases). Cases tested by PCR showed no evidence of a clonal proliferation. None of 21 cases developed lymphoma during clinical follow-up of up to 3 years. The kappa/lambda ratio of CD10+ GC B cells in HT can be skewed markedly beyond that reported in reactive lymph nodes. This finding frequently is present in HT. Pathologists should be familiar with this phenomenon to prevent misdiagnosis of follicular lymphoma in patients with HT.
Chen
Henry I
HI
Department of Pathology, Baylor College of Medicine, Houston, TX, USA.
Akpolat
Ikser
I
Mody
Dina R
DR
Lopez-Terrada
Dolores
D
De Leon
Audrey Ponce
AP
Luo
Yamin
Y
Jorgensen
Jeffrey
J
Schwartz
Mary R
MR
Chang
Chung-Che
CC
D000328:Adult; D000368:Aged; D001402:B-Lymphocytes / Q000276:immunology*; D002999:Clone Cells / Q000276:immunology; D005260:Female; D005434:Flow Cytometry / Q000379:methods; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D018858:Germinal Center / Q000166:cytology; D050031:Hashimoto Disease / Q000276:immunology* / Q000473:pathology; D006801:Humans; D007145:Immunoglobulin kappa-Chains / Q000032:analysis*; D007146:Immunoglobulin lambda-Chains / Q000032:analysis*; D008875:Middle Aged; D015260:Neprilysin / Q000032:analysis; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000276:immunology / Q000473:pathology
D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains; D015260:Neprilysin