Ahmed Muhammad G T, Limmer Andreas, Sucker Christoph, Fares Khaled Mohamed, Mohamed Sahar Abdel-Baky, Othman Ahmed H, Berger Marc Moritz, Brenner Thorsten, Hartmann Matthias
Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany.
Medizinisches Versorgungszentrum (MVZ), COAGUMED Gerinnungszentrum, 10789 Berlin, Germany.
J Clin Med. 2022 Jul 20;11(14):4219. doi: 10.3390/jcm11144219.
CD45 is a transmembrane glycoprotein and protein tyrosine phosphatase expressed on the surface of all nucleated hematopoietic cells. While there is increasing evidence demonstrating the involvement of CD45 in immune system regulation, no information on CD45 expression in inflammation and sepsis is currently available. Therefore, we determined the CD45 surface expression on granulocytes, lymphocytes, and monocytes in patients with COVID-19 and healthy volunteers in both absence and presence of lipopolysaccharide (LPS). Following approval by the local ethics committee, whole blood samples were obtained from patients with COVID-19 infection on day 1 of hospital admission and healthy volunteers. Samples were incubated in absence and presence of LPS and CD45 was measured in granulocytes, lymphocytes, and monocytes using flow cytometry. In comparison with healthy individuals, COVID-19 patients showed an increased CD45 expression on the surface of granulocytes (+35%, p < 0.02) and lymphocytes (+39%, p < 0.0001), but a reduced CD45 expression on monocytes (−35%, p < 0.0001). LPS incubation of whole blood from healthy individuals increased the CD45 expression on granulocytes (+430%, p < 0.0001), lymphocytes (+32%, p = 0.0012), and monocytes (+36%, p = 0.0005), respectively. LPS incubation of whole blood samples from COVID-19 patients increased the CD45 expression on granulocytes and monocytes, and decreased the CD45 expression on lymphocytes. In conclusion, CD45 expression on leucocytes is altered: (1) in COVID-19 patients, and (2) in in vitro endotoxemia in a complex cell-specific way, thus representing a new immunoregulatory mechanism.
CD45是一种跨膜糖蛋白和蛋白酪氨酸磷酸酶，表达于所有有核造血细胞表面。虽然越来越多的证据表明CD45参与免疫系统调节，但目前尚无关于其在炎症和脓毒症中表达的信息。因此，我们测定了新型冠状病毒肺炎（COVID-19）患者和健康志愿者在存在和不存在脂多糖（LPS）的情况下，粒细胞、淋巴细胞和单核细胞表面的CD45表达。经当地伦理委员会批准，在入院第1天从COVID-19感染患者和健康志愿者中采集全血样本。样本在不存在和存在LPS的情况下进行孵育，并使用流式细胞术测定粒细胞、淋巴细胞和单核细胞中的CD45。与健康个体相比，COVID-19患者的粒细胞表面CD45表达增加（+35%，p<0.02），淋巴细胞表面CD45表达增加（+39%，p<0.0001），但单核细胞表面CD45表达降低（-35%，p<0.0001）。健康个体全血经LPS孵育后，粒细胞（+430%，p<0.0001）、淋巴细胞（+32%，p=0.0012）和单核细胞（+36%，p=0.0005）的CD45表达分别增加。COVID-19患者全血样本经LPS孵育后，粒细胞和单核细胞的CD45表达增加，淋巴细胞的CD45表达降低。总之，白细胞上的CD45表达发生了改变：（1）在COVID-19患者中；（2）在体外内毒素血症中以复杂的细胞特异性方式改变，从而代表一种新的免疫调节机制。
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