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Aberrant expression of T-cell markers in acute myeloid leukemia
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Experimental and Molecular Pathology 83 (2007) 462 – 463 www.elsevier.com/locate/yexmp
Aberrant expression of T-cell markers in acute myeloid leukemia Robert E. Lewis, Julius M. Cruse, Catherine M. Sanders ⁎, Rachel N. Webb, Jeanann L. Suggs Department of Pathology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA Received 15 August 2007 Available online 7 September 2007
Abstract According to WHO, several T-cell immunophenotypic markers may be aberrantly expressed in acute myeloid leukemia (AML). TdT may be expressed in greater than one-third of cases, and CD2 and CD7 may be expressed frequently at low intensity; however, the T-cell lineage specific antigen CD3 is usually absent. In this investigation, 30 cases of AML were evaluated for CD2, CD3, CD5, CD7, CD8 and TdT expression, and mean fluorescence intensities (MFI). Of the 3 (10%) cases positive for CD3 and CD8, 1 was bright (MFI N 501), and 2 cases were moderate. TdT was moderately expressed in 4 (13.3%) cases with MFI values between 301 and 500. CD2 and CD5 were positive in 5 (16.7%) cases. While CD2 was moderate in all 5 cases, CD5 was bright in 3, moderate in 1 and dim in 1. Of the 15 (50%) cases positive for CD7, 9 were bright, 5 were moderate, and 1 was dim with a MFI value between 201 and 300. These data indicate that CD2 and CD7 may be frequently expressed at greater intensities than WHO specified. These results point to the need for a more extensive study to evaluate the potential prognostic significance of aberrant T-cell marker expression in AML. © 2007 Elsevier Inc. All rights reserved.
Introduction Acute myeloid leukemia (AML) is a disease involving the presence of a clonal expansion of neoplastic myeloid cells in the blood, bone marrow, and various tissues. Normal bone marrow is replaced by myeloid blast cells which have limited ability to mature (Bain et al., 2001). According to the World Health Organization (WHO), several T-cell immunophenotypic markers may be aberrantly expressed in AML while others are typically absent. TdT may be positively expressed in greater than one-third of cases, and CD2 and CD7 may be expressed frequently at a low intensity; however, the T-cell lineage specific antigen CD3 is usually absent (Jaffe et al., 2001). Fluorescence intensity as related to a single cell is a function of the quantity of antigen on that single cell. The fluorescence intensity of a subpopulation which is normalized against the cell number defines the mean fluorescence intensity (MFI). A MFI value greater than 501 is considered bright expression, while MFI values between 301 and 500 are moderate. MFI values between
⁎ Corresponding author. Fax: +1 601 984 1835. E-mail address: [email protected] (C.M. Sanders). 0014-4800/$ - see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.yexmp.2007.08.010
201 and 300 are considered dim, and MFI values below 200 are negative. Materials and methods Thirty cases of AML were diagnosed based on immunophenotype, clinical assessment, and morphology over the course of four years in the Department of Pathology at the University of Mississippi Medical Center in Jackson. Immunophenotyping was performed by analysis of peripheral blood samples collected in EDTA, bone marrow aspirates, and lymph node cell preparations by flow cytometry (FC500, Beckman Coulter, Miami, FL) using standard techniques.
Results Thirty cases of AML were evaluated for CD2, CD3, CD5, CD7, CD8 and TdT expression, and mean fluorescence intensities (MFI) were quantified (Tables 1 and 2). The percentage of gated myeloid cells expressing a particular CD marker was used to determine whether expression was normal, decreased or negative. Expression of a CD marker by less than 20% of the gated population was considered negative, while expression by less than 50% was considered decreased. Expression greater than 50% of the gated cells was considered normal. A MFI value greater than 501 was considered bright expression, while MFI values between
R.E. Lewis et al. / Experimental and Molecular Pathology 83 (2007) 462–463 Table 1 Number of AML cases expressing aberrant T-cell markers
Positive Negative
Table 2 Expression levels of T-cell immunophenotypic markers in AML cases
CD2
CD3
CD5
CD7
CD8
TdT
5 25
3 27
5 25
15 15
3 27
4 26
301 and 500 were moderate (Fig. 1). MFI values between 201 and 300 were considered dim, and MFI values below 200 were negative (Table 2). Discussion CD2, an adhesion and signal transduction molecule, is expressed by T cells and NK cells (Cruse et al., 2004). In an investigation by Bradstock et al. (1994), CD2 was positive in 16% of AML cases. In the current study, CD2 was expressed moderately in 16.7% cases. The WHO states that CD2 may be frequently expressed at low intensity in AML patients (Jaffe et al., 2001). However, in this study, CD2 was moderately expressed in all positive cases. These data indicate that CD2 may be expressed frequently at a greater intensity than WHO suggests. CD3, a T cell marker, is involved in signal transduction and the assembly of the T cell receptor complex (Cruse et al., 2004). In a study by Bradstock et al. (1994), CD3 was positive in 7% of AML cases. Likewise, in this investigation, CD3 was positive in 10% of AML patients. According to WHO, CD3 is typically absent in AML cases (Jaffe et al., 2001). These data support the current WHO immunophenotype for AML. CD5 is a co-stimulatory molecule found on T cells and B cells and is a key regulator of immune tolerance (Cruse et al., 2004). In this investigation, CD5 was expressed in 16.7% of AML cases. These data indicate that CD5 may be aberrantly expressed often by myeloid cells in AML. CD7, an activation and adhesion molecule, is expressed by T cells, NK cells and stem cells (Cruse et al., 2004). The WHO states that CD7 may be frequently expressed in AML, but at low intensity (Jaffe et al., 2001). In an investigation by Bradstock et al. (1994), CD7 was positive in 28% of AML cases. However, in the current study, CD7 was expressed in 15 (50%) of AML cases of which 9 were bright and 5 were moderate. These data
Fig. 1. Moderate expression of CD7 in AML.
463
Negative (MFI b 200) Dim (201 b MFI b 300) Moderate (301 b MFI b 500) Bright (MFI N 501)
CD2
CD3
CD4
CD5
CD7
CD8
TdT
25 0 5 0
27 0 2 1
16 3 10 1
25 1 1 3
15 1 5 9
27 0 2 1
26 0 4 0
suggest that CD7 may be expressed at a higher intensity than indicated by WHO. In a study conducted by Kita et al. (1993), patients with CD7+ AML had a higher incidence of hepatomegaly and CNS involvement and responded poorly to chemotherapy, suggesting that CD7 may be used as a prognostic indicator for AML patients. CD8, expressed by T cells, is a co-receptor for MHC class I molecules (Cruse et al., 2004). In addition, CD8 is involved in thymocyte development (Abbas and Lichtman, 2005). In this investigation, CD8 was expressed in 10% of AML cases. These data suggest that CD8 may be aberrantly expressed in a few cases of AML. Terminal Deoxynucleotidyl Transferase (TdT) is an early lymphocyte marker involved in the rearrangement of T-cell receptor genes and immunoglobulin (Cruse et al., 2004). According to WHO, TdT may be positively expressed in greater than one-third of cases of AML (Jaffe et al., 2001). However, in this investigation, TdTwas only expressed in 13.3% of AML cases suggesting that TdT may be expressed less frequently than WHO indicates. These results point to the need for a more extensive study to evaluate the potential prognostic significance of aberrant T-cell marker expression in AML. Acknowledgments The authors express genuine appreciation to Mr. John Coker, B.S., MT (NCA), Mrs. Patsy Foley, B.S., MT (ASCP), CHT, CHS (ABHI), and Ms. Susan Touchstone, B.S., MT (ASCP), SBB (AABB), CHT, CHS (ABHI) for their skilled technical expertise in flow cytometric analysis. References Abbas, Abul K., Lichtman, Andrew H., 2005. Cellular and Molecular Immunology. Elsevier, Philadelphia. Bain, Barbara, Clark, D.M., Lampert, I.A., Wilkins, B.S., 2001. Bone Marrow Pathology. Blackwell Science, Oxford. Bradstock, Kenneth, Matthews, Jane, Benson, Elizabeth, Page, Fiona, Bishop, James, the Australian Leukaemia Study Group, 1994. Prognostic value of immunophenotyping in acute mueloid leukemia. Blood 84, 1220–1225. Cruse, Julius, Lewis, R.E., Wang, H., 2004. Immunology Guidebook. Elsevier, San Diego. Jaffe, E.S., Harris, N.L., Stein, H., Vardiman, J.W. (Eds.), 2001. World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Haematopoietic and Lymphoid Tissues. IARC Press, Lyon. Kita, Kenkichi, Miwa, Hiroshi, Nakase, Kazunori, Kawakami, Keiki, Kobayashi, Shirakawa, Shigeru, Tanaka, Isao, Ohta, Chizuko, Tsutani, Hiroshi, Oguma, Shigeru, Kyo, Taiichi, Dohy, Hiroo, Kamada, Nanao, Nasu, Kaori, Uchino, Haruto, 1993. Clinical importance of CD7 expression in acute myelocytic leukemia. Blood 81, 2399–2405.
Experimental and Molecular Pathology 83 (2007) 462 – 463 www.elsevier.com/locate/yexmp
Aberrant expression of T-cell markers in acute myeloid leukemia Robert E. Lewis, Julius M. Cruse, Catherine M. Sanders ⁎, Rachel N. Webb, Jeanann L. Suggs Department of Pathology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA Received 15 August 2007 Available online 7 September 2007
Abstract According to WHO, several T-cell immunophenotypic markers may be aberrantly expressed in acute myeloid leukemia (AML). TdT may be expressed in greater than one-third of cases, and CD2 and CD7 may be expressed frequently at low intensity; however, the T-cell lineage specific antigen CD3 is usually absent. In this investigation, 30 cases of AML were evaluated for CD2, CD3, CD5, CD7, CD8 and TdT expression, and mean fluorescence intensities (MFI). Of the 3 (10%) cases positive for CD3 and CD8, 1 was bright (MFI N 501), and 2 cases were moderate. TdT was moderately expressed in 4 (13.3%) cases with MFI values between 301 and 500. CD2 and CD5 were positive in 5 (16.7%) cases. While CD2 was moderate in all 5 cases, CD5 was bright in 3, moderate in 1 and dim in 1. Of the 15 (50%) cases positive for CD7, 9 were bright, 5 were moderate, and 1 was dim with a MFI value between 201 and 300. These data indicate that CD2 and CD7 may be frequently expressed at greater intensities than WHO specified. These results point to the need for a more extensive study to evaluate the potential prognostic significance of aberrant T-cell marker expression in AML. © 2007 Elsevier Inc. All rights reserved.
Introduction Acute myeloid leukemia (AML) is a disease involving the presence of a clonal expansion of neoplastic myeloid cells in the blood, bone marrow, and various tissues. Normal bone marrow is replaced by myeloid blast cells which have limited ability to mature (Bain et al., 2001). According to the World Health Organization (WHO), several T-cell immunophenotypic markers may be aberrantly expressed in AML while others are typically absent. TdT may be positively expressed in greater than one-third of cases, and CD2 and CD7 may be expressed frequently at a low intensity; however, the T-cell lineage specific antigen CD3 is usually absent (Jaffe et al., 2001). Fluorescence intensity as related to a single cell is a function of the quantity of antigen on that single cell. The fluorescence intensity of a subpopulation which is normalized against the cell number defines the mean fluorescence intensity (MFI). A MFI value greater than 501 is considered bright expression, while MFI values between 301 and 500 are moderate. MFI values between
⁎ Corresponding author. Fax: +1 601 984 1835. E-mail address: [email protected] (C.M. Sanders). 0014-4800/$ - see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.yexmp.2007.08.010
201 and 300 are considered dim, and MFI values below 200 are negative. Materials and methods Thirty cases of AML were diagnosed based on immunophenotype, clinical assessment, and morphology over the course of four years in the Department of Pathology at the University of Mississippi Medical Center in Jackson. Immunophenotyping was performed by analysis of peripheral blood samples collected in EDTA, bone marrow aspirates, and lymph node cell preparations by flow cytometry (FC500, Beckman Coulter, Miami, FL) using standard techniques.
Results Thirty cases of AML were evaluated for CD2, CD3, CD5, CD7, CD8 and TdT expression, and mean fluorescence intensities (MFI) were quantified (Tables 1 and 2). The percentage of gated myeloid cells expressing a particular CD marker was used to determine whether expression was normal, decreased or negative. Expression of a CD marker by less than 20% of the gated population was considered negative, while expression by less than 50% was considered decreased. Expression greater than 50% of the gated cells was considered normal. A MFI value greater than 501 was considered bright expression, while MFI values between
R.E. Lewis et al. / Experimental and Molecular Pathology 83 (2007) 462–463 Table 1 Number of AML cases expressing aberrant T-cell markers
Positive Negative
Table 2 Expression levels of T-cell immunophenotypic markers in AML cases
CD2
CD3
CD5
CD7
CD8
TdT
5 25
3 27
5 25
15 15
3 27
4 26
301 and 500 were moderate (Fig. 1). MFI values between 201 and 300 were considered dim, and MFI values below 200 were negative (Table 2). Discussion CD2, an adhesion and signal transduction molecule, is expressed by T cells and NK cells (Cruse et al., 2004). In an investigation by Bradstock et al. (1994), CD2 was positive in 16% of AML cases. In the current study, CD2 was expressed moderately in 16.7% cases. The WHO states that CD2 may be frequently expressed at low intensity in AML patients (Jaffe et al., 2001). However, in this study, CD2 was moderately expressed in all positive cases. These data indicate that CD2 may be expressed frequently at a greater intensity than WHO suggests. CD3, a T cell marker, is involved in signal transduction and the assembly of the T cell receptor complex (Cruse et al., 2004). In a study by Bradstock et al. (1994), CD3 was positive in 7% of AML cases. Likewise, in this investigation, CD3 was positive in 10% of AML patients. According to WHO, CD3 is typically absent in AML cases (Jaffe et al., 2001). These data support the current WHO immunophenotype for AML. CD5 is a co-stimulatory molecule found on T cells and B cells and is a key regulator of immune tolerance (Cruse et al., 2004). In this investigation, CD5 was expressed in 16.7% of AML cases. These data indicate that CD5 may be aberrantly expressed often by myeloid cells in AML. CD7, an activation and adhesion molecule, is expressed by T cells, NK cells and stem cells (Cruse et al., 2004). The WHO states that CD7 may be frequently expressed in AML, but at low intensity (Jaffe et al., 2001). In an investigation by Bradstock et al. (1994), CD7 was positive in 28% of AML cases. However, in the current study, CD7 was expressed in 15 (50%) of AML cases of which 9 were bright and 5 were moderate. These data
Fig. 1. Moderate expression of CD7 in AML.
463
Negative (MFI b 200) Dim (201 b MFI b 300) Moderate (301 b MFI b 500) Bright (MFI N 501)
CD2
CD3
CD4
CD5
CD7
CD8
TdT
25 0 5 0
27 0 2 1
16 3 10 1
25 1 1 3
15 1 5 9
27 0 2 1
26 0 4 0
suggest that CD7 may be expressed at a higher intensity than indicated by WHO. In a study conducted by Kita et al. (1993), patients with CD7+ AML had a higher incidence of hepatomegaly and CNS involvement and responded poorly to chemotherapy, suggesting that CD7 may be used as a prognostic indicator for AML patients. CD8, expressed by T cells, is a co-receptor for MHC class I molecules (Cruse et al., 2004). In addition, CD8 is involved in thymocyte development (Abbas and Lichtman, 2005). In this investigation, CD8 was expressed in 10% of AML cases. These data suggest that CD8 may be aberrantly expressed in a few cases of AML. Terminal Deoxynucleotidyl Transferase (TdT) is an early lymphocyte marker involved in the rearrangement of T-cell receptor genes and immunoglobulin (Cruse et al., 2004). According to WHO, TdT may be positively expressed in greater than one-third of cases of AML (Jaffe et al., 2001). However, in this investigation, TdTwas only expressed in 13.3% of AML cases suggesting that TdT may be expressed less frequently than WHO indicates. These results point to the need for a more extensive study to evaluate the potential prognostic significance of aberrant T-cell marker expression in AML. Acknowledgments The authors express genuine appreciation to Mr. John Coker, B.S., MT (NCA), Mrs. Patsy Foley, B.S., MT (ASCP), CHT, CHS (ABHI), and Ms. Susan Touchstone, B.S., MT (ASCP), SBB (AABB), CHT, CHS (ABHI) for their skilled technical expertise in flow cytometric analysis. References Abbas, Abul K., Lichtman, Andrew H., 2005. Cellular and Molecular Immunology. Elsevier, Philadelphia. Bain, Barbara, Clark, D.M., Lampert, I.A., Wilkins, B.S., 2001. Bone Marrow Pathology. Blackwell Science, Oxford. Bradstock, Kenneth, Matthews, Jane, Benson, Elizabeth, Page, Fiona, Bishop, James, the Australian Leukaemia Study Group, 1994. Prognostic value of immunophenotyping in acute mueloid leukemia. Blood 84, 1220–1225. Cruse, Julius, Lewis, R.E., Wang, H., 2004. Immunology Guidebook. Elsevier, San Diego. Jaffe, E.S., Harris, N.L., Stein, H., Vardiman, J.W. (Eds.), 2001. World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Haematopoietic and Lymphoid Tissues. IARC Press, Lyon. Kita, Kenkichi, Miwa, Hiroshi, Nakase, Kazunori, Kawakami, Keiki, Kobayashi, Shirakawa, Shigeru, Tanaka, Isao, Ohta, Chizuko, Tsutani, Hiroshi, Oguma, Shigeru, Kyo, Taiichi, Dohy, Hiroo, Kamada, Nanao, Nasu, Kaori, Uchino, Haruto, 1993. Clinical importance of CD7 expression in acute myelocytic leukemia. Blood 81, 2399–2405.