A New Discovery Of Low Proliferative Activity Of B Lymphocytes In The Mantle Zone Of Lymph Nodes

Objective:Mantle cell lymphoma is a type of B-cell lymphoma with unique biological characteristics,which covers the characteristics of both indolent lymphoma and aggressive lymphoma.The prognosis is poor and its pathogenesis is not clear.In the previous study,we found for the first time that B cells in the mantle zone of lymph nodes are those with low proliferative activity,which we speculated may be correlated with the indolent characteristics of mantle cell lymphoma.On the basis of this,we further detected the proliferation activity of mantle cells by immunohistochemistry,special staining,TUNEL apoptosis detection and other methods to confirm its indolent lymphocyte characteristics.Methods:From January 2016 to December 2019,100 cases of normal lymph nodes(non-metastatic lymph nodes from tumor patients),40 cases of reactive hyperplastic lymph nodes(from lymph node biopsies of non-tumor case)were collected from the Department of Pathology of Shaanxi Provincial people’s Hospital.All cases were checked by senior medical doctors through rereading pathological sections,and lymphomas were excluded.We sorted out clinicopathological data,and performed Ki-67,PCNA immunohistochemical staining(MaxVision method),AgNOR staining,and TUNEL apoptosis detection on all tissues.Then we observed the expression and detection level of the above four indicators in the lymph node germinal center,mantle zone,interfollicular area and the medulla area.Results:1.The expression of Ki-67 was different in germinal center,mantle zone,interfollicular area and medulla area of normal lymph nodes and reactive hyperplastic lymph nodes,with the high expression and the highest proliferative index in germinal center(The germinal center index of normal lymph nodes was 91.00(3.00),and that of reactive hyperplastic lymph nodes was 90.00(4.75))and the lowest in mantle zone(The index of normal lymph node mantle zone was about 1.90(2.00);that of reactive hyperplasia was about 0.80(1.075)).The different expression of Ki-67 in mantle zone and interfollicular area,mantle zone and medulla area of lymph node was statistically significant(P < 0.05).2.The expression of PCNA was different in germinal center,mantle zone,interfollicular area and medulla area of normal lymph nodes and reactive hyperplasticlymph nodes,with the high expression the highest proliferative index in germinal center(The germinal center index of normal lymph nodes was 91.00(4.00),and that of reactive hyperplastic lymph nodes was 87.50(12.5))and the lowest in mantle zone(The index of normal lymph node mantle zone was about 1.00(1.40);that of reactive hyperplasia was about 0.65(0.15)).The different expression of PCNA in mantle zone and interfollicular area,mantle zone and medulla area of lymph node was statistically significant(P < 0.05).3.AgNOR could be detected in germinal center,mantle zone,interfollicular area and medulla area of normal lymph nodes and reactive hyperplastic lymph nodes,with the highest AgNOR count in germinal center(The AgNOR count of normal lymph node germinal center was about 6.29(1.95);the AgNOR count of reactive hyperplastic lymph node germinal center was about 5.28(1.7))and the lowest AgNOR count in mantle zone(The AgNOR count of normal lymph node mantle zone was 1.16(0.14),and that of reactive hyperplastic lymph node mantle zone was about 1.11(0.08)).The AgNOR counts of normal lymph nodes and reactive hyperplastic lymph nodes were statistically different in the mantle zone and interfollicular area,the mantle zone and medulla area(P < 0.05).4.The apoptotic index was different in germinal center,mantle zone,interfollicular area and medulla area of normal lymph nodes and reactive hyperplastic lymph nodes.The apoptotic index of TUNEL in germinal center was the highest(The apoptotic index of the germinal center of normal lymph node was about 4.00(4.075);the apoptotic index of the germinal center of reactive hyperplastic lymph node was about 2.85(4.075))and that in mantle zone was the lowest(The apoptosis index of normal lymph node mantle zone was0.20(0.20);that of reactive hyperplastic lymph node mantle zone was about 0.10(0.10)).The TUNEL apoptotic indexes of normal lymph nodes and reactive hyperplastic lymph nodes were statistically different in the mantle zone and interfollicular area,the mantle zone and medulla area(P < 0.05).Conclusion:1.Ki-67,PCNA proliferative index and AgNOR count exhibited significant differences in germinal center,mantle zone,interfollicular area and medulla area of lymph nodes,among which B cell proliferation activity in mantle zone of lymph nodes was the lowest,and apoptosis index of B cells in mantle zone of lymph nodes was the lowest by TUNEL apoptosis detection.2.B cells in the mantle zone of lymph nodes are extremely inactive and have the characteristics of indolent lymphocytes.It is speculated that the unique biological characteristics of mantle cell lymphoma may be related to the characteristics of indolent lymphocytes of B cells in the mantle zone of lymph nodes.