[1408] Flow Cytometric Evaluation of Programmed Death-1 (PD1) in Benign and Neoplastic Lymphoid Proliferations

Kelly J Garner, Stephen P TenEyck, Steven H Swerdlow, Raymond E Felgar. University of Pittsburgh, Pittsburgh, PA

Background: PD-1, a member of the CD28 family, has been promoted as a marker of T follicular helper (TFH) cells, and a way to help identify angioimmunoblastic type T-cell lymphoma, a neoplasm of TFH, and other T-cell lymphomas of TFH type. PD-1 is also expressed in a smaller proportion of other T-cell and B-cell neoplasms. Expanded populations of PD-1+ T-cells in reactive settings may also cause confusion with a T-cell neoplasm.
Design: 8 color flow cytometric studies were performed on blood, bone marrow, and tissue samples using antibodies to PD-1 (CD279) (Clone J01, PE-labeled, E-Bioscience, San Diego, CA), CD3-PE-Cy7, CD4-V500, CD8-APC-H7, CD10-APC, CD57-FITC, CD5-V450 and CD19-PerCP-Cy5.5 (all from Becton Dickinson, San Jose, CA). Data were acquired with a FACSCanto-II and analyzed with FACS-Diva Software.
Results: Samples included 22 non-malignant/reactive bloods, bone marrows, lymph nodes, and spleens. In addition, 16 chronic lymphocytic leukemia / small lymphocytic lymphomas (CLL/SLL), 3 follicular lymphomas (FL), 3 diffuse large B-cell lymphomas (DLBCL), and 2 MALT lymphomas were investigated. 11/16 CLL/SLL and 4/7 evaluable B-NHLs showed dim PD-1 expression in ≥20% of neoplastic B-cells at a weaker intenstiy than admixed T-cells. PD-1 staining results are summarized in Table 1.

Table 1: PD-1+ Lymphocyte Subsets (Mean ± Std Dev)
  PD1+ Subsets (% of PD1+ Mononuclear Cells)PD1+ T-cell subsets (Percent of CD3+PD1+ Lymphocytes)
DiagnosisTotal PD1+ Mononuclear CellsCD3+PD1+ T-cellsCD19+PD1+ B-cellsCD4+ T-cellsCD8+ T-cellsCD10+ T-cellsCD57+ T-cells
CLL/SLL (16)37.5 ± 17.816.4 ± 17.478.7 ± 20.251.6 ± 15.631.7 ± 18.50.81 ± 0.7131.9 ± 15.3
FL (3)25.3 ± 7.374.1 ± 17.619.9 ± 17.472.7 ± 7.419.3 ± 5.87.6 ± 5.524.4 ± 7.1
DLBCL (3)36.3 ± 19.856.3 ± 31.521.1 ± 21.626.2 ± 20.831.6 ± 30.43.3 ± 4.046.3 ± 18.9
MALT (Orbit, 2)25.342.356.080.014.21.329.2
 68.168.130.181.614.86.115.8
Blood, NM (4)15.2 ± 6.084.6 ± 9.16.9 ± 7.650.7 ± 10.140.2 ± 9.31.1 ± 1.123.7 ± 6.9
Bone Marrow, NM (5)29.7 ± 12.451.1 ± 21.62.06 ± 1.8341.5 ± 13.148.9 ± 12.30.24 ± 0.2315.3 ± 10.8
Lymph Node, NM (12)23.7 ± 7.884.6 ± 9.612.9 ± 9.780.3 ± 6.912.2 ± 6.71.94 ± 2.1511.7 ± 7.9
Spleen, NM (1)17.566.325.725.929.93.710.1
NM = Non-Malignant (Reactive)


Conclusions: PD1 is expressed in a subset of lymphocytes in blood, bone marrow, lymph nodes, and spleen. Most PD1+ lymphocytes in non-neoplastic samples are CD3+ T-cells, with both CD4+ and significant CD8+ subsets of PD1+ T-cells, including non-TFH T-cells. PD1 is also seen on CLL/SLL and subset(s) of neoplastic B-cells in other B-NHLs.
Category: Hematopathology

Wednesday, March 21, 2012 9:30 AM

Poster Session V # 199, Wednesday Morning

 

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