[1520] Microenvironment in Nodular Lymphocyte Predominant Hodgkin Lymphoma, Classical Hodgkin Lymphoma and T-Cell/Histiocyte Rich Large B-Cell Lymphoma: An Immunohistochemical Comparison

Sonam Prakash, Yen-Chun Liu, Daniel M Knowles, Attilio Orazi, Wayne Tam. Weill Cornell Medical College, New York

Background: A characteristic feature of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is the presence of CD4+/CD57+ rosettes around the LP cells, a finding of uncertain biological significance. A previous study demonstrated that the CD4+/CD57+ cells in NLPHL have a Tr1 regulatory T-cell (T-regs) cytokine profile. Tr1 cells are a subset of T-regs that are CD4+, CD25+ and express IL10. The goal of this study was to evaluate if the T-cell rosettes around LP cells represent Tr1 cells and to see if the T-cells surrounding the neoplastic cells in NLPHL or classical Hodgkin lymphoma (CHL) or T-cell/histiocyte rich large B-cell lymphoma (THRLBCL) have a characteristic immunophenotype that can be utilized in their differential diagnosis.
Design: We studied 7 cases of NLPHL, 9 cases of CHL (4 lymphocyte rich and 5 mixed cellularity) and 4 cases of THRLBCL. Immunohistochemical stains for CD20, CD3, IL10, CD25, FOXP3, CD4, CD57, and MUM1 were performed on formalin-fixed paraffin-embedded tissue from these cases. The immunohistochemical profile of the neoplastic cells as well as that of the T-cells rosetting them was studied.
Results: In all cases of NLPHL, the T-cells rosetting the LP cells were positive for CD4, at least partially positive for CD57 and MUM1 but negative for IL10 and FOXP3. Only 1 case showed CD25 positive rosettes around the LP cells. The cells rosetting the Reed-Sternberg (R-S) cells in CHL were partially positive for MUM1 and negative for IL10 and FOXP3 in all cases and positive for CD25 in 2 of 9 cases. The cells rosetting the neoplastic cells in THRLBCL were partially positive for MUM1 and negative for IL10, FOXP3 and CD25 in all cases. The LP cells in NLPHL were positive for MUM1 in 2/7 cases, CD25 in 5/7 cases and IL10 in 2/7 cases. The R-S cells in CHL were positive for MUM1 in 9/9 cases, CD25 in 8/9 cases and IL10 in 6/9 cases. The neoplastic cells in THRLBCL were positive for MUM1 in 3/4 cases, CD25 in 3/4 cases and IL10 in 2/4 cases.
Conclusions: The T-cell rosettes around the LP cells in NLPHL lack expression of IL10 and CD25 and therefore, do not appear to be Tr1 cells. The T-cell rosettes around the neoplastic cells in NLPHL, CHL and THRLBCL do not show significant differences in the expression of IL10, CD25, FOXP3 and MUM1. The expression of IL10 by the neoplastic cells in NLPHL, CHL and THRLBCL raises the possibility of an autocrine regulatory loop. Although the expression of MUM1 is constant in R-S cells in CHL, it can also be seen in the neoplastic cells of NLPHL and THRLBCL.
Category: Hematopathology

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 206, Wednesday Morning


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