Objective: To study the pathological changes of the spleen in patients with COVID-19 and to analyze the relationship between the weakened immune system and splenic lesions. Methods: Postmortem needle autopsies from the spleen were carried out on 10 patients who died from COVID-19 in Wuhan. Routine hematoxylin and eosin (HE) staining was used to observe the pathological changes. The changes of lymphocytes were studied further with immunohistochemistry.RT-PCR was used to detect 2019-nCoV RNA in the spleen. In addition,the Epstein-Barr virus (EBV) was detected by in situ hybridization, and coronavirus particles were detected by transmission electron microscopy in 2 cases. Results: There were 7 males and 3 females, with an average age of 68.3 years.Of the 10 cases, 4 had cancer history and another 4 had other underlying diseases respectively.Cough, fever, malaise and dyspnea were the main clinical symptoms.The time from onset to death was 15-45 days.Ten cases patients had normal or slight increase in peripheral blood leukocyte count in the early stage of the disease, 6 cases had significant increase before death. Five patients' peripheral blood lymphocyte count decreased in the early stage of the disease, and 10 patients' peripheral blood lymphocyte count decreased significantly before the disease progressed or died. Seven cases were treated with corticosteroid (methylprednisolone ≤40 mg/d, not more than 5 days). Histopathological examination showed that the cell composition of the spleen decreased, white pulp atrophied at different levels, meanwhile lymphoid follicles decreased or absent;in addition, the ratio of red pulp to white pulp increased with varying degrees. In 7 cases, more neutrophil infiltration was found, and in 5 cases, scattered plasma cell infiltration was found. Macrophage proliferation and hemophagocytic phenomena in a few cells were found in a case. Meanwhile, necrosis and lymphocyte apoptosis were detected in 2 cases, small artery thrombosis and spleen infarction in 1 case, and fungal infection in 1 case. The results of immunohistochemistry showed that the T and B lymphocyte components of the spleen in all cases decreased in varying degrees. CD20(+) B cells were found to accumulate in the lymphoid sheath around the splenic artery in 8 cases. However, CD20 and CD21 immunostaining in 2 cases showed that the number of white pulp was almost normal, and splenic nodules were atrophic. CD3(+), CD4(+) and CD8(+)T cells were decreased. In 9 cases,CD68(+) macrophages were no significant changes in the distribution and quantity. While more CD68(+) cells were found in the medullary sinuses of 1 case (related to fungal infection). Few CD56(+) cells were found. EBV was negative by in situ hybridization. RT-PCR was used to detect the nucleic acid of 2019-nCoV. One of 10 cases was positive, 39 years old,who was the youngest patient in this group, and the other 9 cases were negative. Coronavirus particles were found in the cytoplasm of macrophage under electron microscope in 2 cases. Conclusions: The death of COVID-19 occurs mainly in the elderly, and some cases have no underlying diseases. Spleen may be one of the organs directly attacked by the virus in some patients who died from COVID-19. T and B lymphocyte in the spleen decrease in varying degrees, lymphoid follicles are atrophied, decreased or absent, and the number of NK cells do not change significantly. And the pathological changes of the spleen are not related to the use of low dose corticosteroid, which may be related to the direct attack of virus and the attack of immune system on its own tissues.
目的： 观察新型冠状病毒感染疾病（COVID-19）患者的脾脏病理改变，探讨患者免疫系统功能低下与脾脏病变之间的关系。 方法： 对武汉地区10例因COVID-19死亡患者进行穿刺尸检，获取脾脏组织。采用常规HE染色观察脾脏的形态学改变，免疫组织化学染色分析脾脏的免疫结构变化，逆转录-聚合酶链反应（RT-PCR）方法检测脾脏中新型冠状病毒（2019-nCoV）核酸，原位杂交检测EB病毒，2例行透射电镜查找冠状病毒颗粒，并结合患者的临床资料进行分析。 结果： 男性7例，女性3例；年龄39~87岁，平均年龄68.3岁。10例中4例有癌症病史，4例有基础性疾病。咳嗽、发热、全身乏力及呼吸困难是主要的临床症状。患者从症状出现到死亡的时间15~45 d。10例患者外周血白细胞计数在疾病早期正常或轻度增高，6例患者死亡前明显增高，5例患者外周血淋巴细胞计数在疾病早期便出现减少，10例患者在疾病进展或死亡前均明显减少。7例患者使用激素治疗（甲泼尼龙≤40 mg/d，连用不超过5 d）。组织病理学改变见脾脏细胞成分减少，白髓呈不同程度萎缩，淋巴滤泡减少或缺如；红髓与白髓比例不同程度升高；70%病例见较多中性粒细胞浸润，50%病例见散在浆细胞浸润；1例见巨噬细胞增生，少数细胞内见嗜血现象；2例检出坏死及淋巴细胞凋亡；1例检出小动脉血栓及脾脏梗死；1例出现真菌感染及髓窦内见泡沫状组织细胞增生。免疫组织化学检测显示所有病例脾脏T、B淋巴细胞成分均呈不同程度的减少。8例COVID-19患者的脾脏见CD20(+)B细胞聚集于脾动脉周围淋巴鞘，2例CD20及CD21显示白髓数量大致正常，淋巴滤泡萎缩。CD3(+)、CD4(+)及CD8(+)T细胞均减少。CD68显示9例巨噬细胞分布及数量无明显变化，1例髓窦内见较多CD68阳性细胞（与合并真菌感染有关）。查见个别CD56阳性细胞。原位杂交检测EB病毒均为阴性。RT-PCR方法检测2019-nCoV核酸，10例中有1例阳性，为本组病例中最年轻的39岁患者，其余9例均为阴性。2例电镜下在巨噬细胞胞质内查见冠状病毒颗粒。 结论： COVID-19死亡患者以老年为主，部分病例无基础疾病。脾脏可能是部分COVID-19患者被病毒直接攻击的靶器官之一，脾脏T、B淋巴细胞成分均呈不同程度减少，脾小结萎缩、减少或缺如，自然杀伤细胞数量无明显变化。脾脏病理改变与低剂量激素使用无关，可能与病毒直接攻击及机体免疫系统对自身组织的攻击有关系。.
Keywords: COVID-19; Pathologic processes; Punctures; Spleen.