Journal of Pathology and Translational Medicine

Original Articles

Diagnostic Usefulness of Monoclonal Antibody for T Lymphoblastic Lymphoma/Acute Lymphoblastic Leukemia-Specific JL1 Antigen in Paraffin Embedded Tissue.: Chan Sik Park, Seong Hoe Park; Korean J Pathol. 1999;33(11):1033-1038.

Abstract PDF: JL1 is a novel human thymocyte differentiation antigen, which is exclusively expressed by double positive (CD4+ CD8+) cortical thymocytes. We previously reported that the JL1 antigen was selectively expressed on the surface of acute lymphoblastic leukemia cells. T-Lymphoblastic lymphoma/acute lymphoblastic leukemia (T-LBL/ALL), the 6th prevalent lymphoma in Korea, is composed of immature neoplastic lymphoid cells and shows a rapid response to appropriate treatment. Early and precise diagnosis of LBL/ALL is crucial. Light microscopic distinction of LBL/ALL from other non-Hodgkin's lymphomas can sometimes be difficult and is aided by immunophenotypic studies. This study is designed to investigate the diagnostic utility of anti-JL1 monoclonal antibody (YG5) for LBL/ALL in formalin fixed, paraffin embedded tissue. We collected 25 cases of LBL/ALL (18 T-cell, 5 B-cell and 2 undetermined lineage) from 1993 through 1998. We confirmed the diagnosis using morphologic and immunophenotypic data. Strong JL1 expression along cell membrane was observed in 16 out of 18 T-LBL/ALL cases (89%). In 28 cases of other types of lymphomas of including 7 cases of non-T LBL/ALL and 14 cases of small round cell tumors, no JL1 expression was identified. These results show that the immunostaining for JL1 using YG5 on paraffin embedded sections can be useful for the specific diagnosis of T-LBL/ALL in routine diagnostic service.

Expression Pattern of the Cortical Immature Thymocyte Specific Antigen JL1 in Thymomas; a New Adjunctive Diagnostic Marker.: Young Soo Park, Youngji Kim, Yun Hee Lee, Joo Ryung Huh, Chan Sik Park; Korean J Pathol. 2008;42(5):251-259.

Abstract PDF: BACKGROUND
JL1 is a novel antigen that has been reported to be expressed exclusively in immature CD4 CD8 double positive T-cells in the thymic cortex. Thymomas are often infiltrated with lymphocytes that are mostly immature T-cells. METHODS: We evaluated 67 cases of surgically resected thymomas and reviewed their histological, surgical, and clinical findings. Representative sections were immunostained using anti-JL1 monoclonal antibody and the immunostaining score was evaluated in each case. RESULTS: JL1 was strongly positive in immature T cells infiltrated in various subtypes of thymomas. The mean value of the immunostaining score was 0 for type A, 0.24 for the A areas of type AB, 2.71 for the B areas of type AB, 3 for type B1, 1.87 for type B2, 0.67 for type B3, and 0.13 for type C. The immunostaining score correlated with the histological subtypes according to the WHO classification, and stages according to the modified Masaoka system. CONCLUSION: JL1 was specifically detected in immature thymocytes in thymomas. Therefore, JL1 immunostaining can be useful for subtyping thymomas. JL1 can also serve as an adjunctive marker to diagnose thymomas in small biopsy specimens.

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