Cytokine storm and histopathological findings in 60 cases of COVID-19-related death: from viral load research to immunohistochemical quantification of major players IL-1\u3b2, IL-6, IL-15 and TNF-\u3b1

This study involves the histological analysis of samples taken during autopsies in cases of COVID-19 related death to evaluate the inflammatory cytokine response and the tissue localization of the virus in various organs. In all the selected cases, SARS-CoV-2 RT-PCR on swabs collected from the upper (nasopharynx and oropharynx) and/or the lower respiratory (trachea and primary bronchi) tracts were positive. Tissue localization of SARS-CoV-2 was detected using antibodies against the nucleoprotein and the spike protein. Overall, we tested the hypothesis that the overexpression of proinflammatory cytokines plays an important role in the development of COVID-19-associated pneumonia by estimating the expression of multiple cytokines (IL-1\u3b2, IL-6, IL-10, IL-15, TNF-\u3b1, and MCP-1), inflammatory cells (CD4, CD8, CD20, and CD45), and fibrinogen. Immunohistochemical staining showed that endothelial cells expressed IL-1\u3b2 in lung samples obtained from the COVID-19 group (p\u2009<\u20090.001). Similarly, alveolar capillary endothelial cells showed strong and diffuse immunoreactivity for IL-6 and IL-15 in the COVID-19 group (p\u2009<\u20090.001). TNF-\u3b1 showed a higher immunoreactivity in the COVID-19 group than in the control group (p\u2009<\u20090.001). CD8\u2009+\u2009T cells where more numerous in the lung samples obtained from the COVID-19 group (p\u2009<\u20090.001). Current evidence suggests that a cytokine storm is the major cause of acute respiratory distress syndrome (ARDS) and multiple organ failure and is consistently linked with fatal outcomes

Tumors characterized by the presence of HMB45-positive perivascular epithelioid cell (PEC) - A novel entity in surgical pathology

Perivascular Epithelioid Cell (PEC) is a recently identified novel cell type expressing both markers of muscle nature and melanogenesis. PEC has been identified in numerous lesions, such as angiomyolipoma, lymphangioleiomyomatosis, lymphangioleiomyoma and clear cell 'sugar' tumor. We have proposed the unifying concept of a family of lesions characterised by the presence of PECs. Most of these lesions are strictly related to the genetic syndrome of tuberous sclerosis (TS). Some of these lesions can mimic other tumors, particularly clear cell carcinomas and clear cell sarcomas. The importance of a correct diagnosis is stressed by the fact that most PEC lesions have a benign clinical behaviour. Here we summarise our recent experience on this family of tumors

The impact of P53 and P21(waf1) expression on the survival of patients with the germinal center phenotype of diffuse large B-cell lymphoma

Immunohistochemically detected over-expression of P53-related protein (P53+++) and absence of P21(waf1) expression (P21-) correspond to loss of function of the P53-gene in diffuse large B-cell lymphoma (DLBCL) patients. Using immunohistochemistry we examined 80 patients with DLBCL and found that 23% had the P53+++/P21- phenotype while 51% had a germinal center (GC) pattern. Both the P53+++/P21- phenotype and the non-GC pattern were associated with inferior outcome. Notably, the prognostic power of the P53+++/P21- phenotype was restricted to patients with a GC pattern, without effect on outcome of patients with a non-GC phenotype. Our results show that immunohistochemistry can parallel gene expression profiling in addressing clinical variability of DLBCL patients

Abnormal expression of the p53-binding protein MDM2 in Hodgkin's disease

The possible involvement of p53 tumor suppressor gene in the pathogenesis of Hodgkin's disease (HD) is suggested by the frequent finding of abnormal accumulation of p53 protein in the nuclei of Reed-Sternberg cells and their variants (H-RS) in a large proportion of cases. This finding, besides being consistent with the presence of p53 gene mutations, might represent a consequence of the inactivating interaction between p53 and p53-binding proteins such as the product of the MDM2 cellular oncogene. We have examined an unselected series of 77 HD cases of different histologic patterns for the expression of p53 and MDM2 proteins, using specific monoclonal antibodies and sensitive immunohistochemical techniques in single- and double-marker combination. In the large majority of cases (66/77), a variable proportion of H-RS cells expressed MDM2 that was strictly confined to the nuclei. Coexpression of both MDM2 and p53 was common in the same cells. The abnormal nuclear expression of p53 and MDM2 did not seem to correlate with the presence of Epstein-Barr virus infection, as shown by the results of LMP-1 antigen expression and EBER in situ hybridization analysis. Our data suggest that the abnormal accumulation of MDM2 and p53 proteins in HD might reflect a derangement of molecular mechanisms that could play a pathogenetic role in this disease

Immunohistochemical Analysis of Sarcoid Granulomas: Evaluation of Ki67+ and Interleukin-1+ Cells

Proliferating cells have been immunophenotypically characterized in lymph node and bronchoalveolar lavage (BAL) samples obtained from patients with active and inactive sarcoidosis with the cell-cycle-related antigen Ki67. Ki67 monoclonal antibody was used by combined immunohistochemical methods together with antibodies recognizing macrophage- and T-cell-subset-related antigens using avidin-biotin peroxidase (ABC) and alkaline phosphatase-anti-alkaline phosphatase (APAAP) systems. Many proliferating Ki67+ cells were found in affected mediastinal lymph nodes. These cells were mainly located around granulomas and exhibited phenotypical markers of helper/inducer T cells (CD3+, CD4+). Ki67+ macrophages could not be detected in the same lesions with this technique. A different picture was found in BAL preparations where proportions of both T lymphocytes and macrophages were Ki67+. The presence of replicating lymphocytes could be correlated to disease activity, whereas the proportions of Ki67+ macrophages did not show significant differences between active and inactive disease. Interleukin-1 (IL-1) expression was investigated in the same samples with a specific antiserum. Epithelioid macrophages in granulomas and BAL macrophages in all cases exhibited cytoplasmic staining revealing an activated status. Interestingly, giant cells in granulomas were mainly devoid of IL-1 immunoreactivity. These studies support the concept that activated cells at different sites of ongoing inflammation play a central role in the mechanisms accounting for granuloma formation

Immunohistochemical Evidence of Active Thymocyte Proliferation in Thymoma: Its Possible Role in the Pathogenesis of Autoimmune Diseases

Eight cases of human thymoma have been analyzed on cryostat sections with the monoclonal antibody Ki67, which reacts with cells in the proliferative phases of the cell cycle. The aim was to assess the proportion of proliferating thymocytes among lymphoid cells in the thymoma samples. In all cases a large number of cells (mean, 58.75%; range, 35-80%), recognized as thymocytes by morphology and lack of cytokeratin expression in a combined immunohistochemical assay, exhibited nuclear Ki67 staining. These findings differ from the reactivity pattern observed in age-matched nonneoplastic thymuses where lower growth activity of cortical thymocytes was observed (15-20% Ki67+ cells). Intensive thymocyte proliferation in thymomas may represent one of the factors which lead to autoimmunity in myasthenia gravis and thymomas