[1404] Evaluation of Lymphocyte Subsets of Nodular Lymhocyte Predominant Hodgkin Lymphoma, Classical Hodgkin Lymphoma, and T Cell/Histiocyte-Rich Large B-Cell Lymphoma by Flow Cytometry

Jonathan R Fromm, David Wu. University of Washington, Seattle, WA

Background: Classical Hodgkin lymphoma (CHL), nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), and T-cell/histiocyte rich large B-cell lymphoma (T/HCRLBCL) are unique types of B-cell lymphoma in which the neoplastic cells are outnumbered by the reactive infiltrate. While some studies have examined the reactive infiltrate in CHL and NLPHL, a comprehensive evaluation of the reactive infiltrate in T/HCRLBCL is lacking. The utility of evaluating the reactive infiltrate in these neoplasms was also examined.
Design: Lymphocyte subset profiles by flow cytometry were obtained retrospectively for 27 NLPHL, 14 T/HCRLBCL, 34 CHL, and 49 reactive lymph nodes. For the 4 groups, the presence of CD4+ T cells with bright expression of CD45 and CD7 (CD3+/CD4+/CD7bright/CD45bright), the percentage of T cells co-expressing CD4 and CD8, CD4 to CD8 ratio, and percentage of T cells, B cells, NK cells, NK-T cells, CD4+ T cells, CD8+ T cells and plasma cells were measured. Fischer's exact test was used to compare between diagnoses the proportion of cases having the CD3+/CD4+/CD7bright/CD45bright subset. For each reactive cell type, the one-sided ANOVA and Tukey's tests were used to evaluate for differences between groups.
Results: The CD3+/CD4+/CD7bright/CD45bright subset was present in the reactive infiltrate of CHL (76.5%) and T/HCRLBCL (83.3%) but not in NLPHL (8%) or reactive cases (4.1%); 6 of 8 of the negative CHL cases were from HIV+ patients. CD4+/CD8+ T cells were in highest proportion in NLPHL (11.7%) which differed significantly from T/HCRLBCL (2.83%), CHL (2.45%), and reactive cases (2.88%). T/HCRLBCL showed significantly increased CD4/CD8 ratios compared to CHL and reactive cases but not NLPHL. All 3 neoplasms demonstrated increased T cells and decreased B cells compared to reactive cases and the proportion of T cells and B cells is increased and decreased, respectively, in T/HCRLBCL relative to the other neoplasms. Significant differences in the means were identified for the proportion of CD4+ T cells, plasma cells, and NK cells but not NK/T cells or CD8+ T cells.
Conclusions: Significant differences in the reactive infiltrate are identified in these B cell neoplasms and the differences appear to be diagnostically useful (presence of CD3+/CD4+/CD7bright/CD45bright subset suggesting CHL or T/HCRLBCL with rare B cells supporting T/HCRLBCL). In contrast to prior reports, in this study most T/HCRLBCL show a very high CD4/CD8 ratio. Further studies are required to determine the etiology of these findings.
Category: Hematopathology

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 207, Wednesday Morning

 

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