SARS-CoV-2 Infection-Associated Hemophagocytic Lymphohistiocytosis

Low Percentage of Perforin-Expressing NK Cells during Severe SARS-CoV-2 Infection: Consumption Rather than Primary Deficiency

Genetic defects in the ability to deliver effective perforin have been reported in patients with hemophagocytic lymphohistiocytosis. We tested the hypothesis that a primary perforin deficiency might also be causal in severe SARS-CoV-2 infection. We recruited 54 volunteers confirmed as being SARS-CoV-2-infected by RT-PCR and admitted to intensive care units or non-intensive care units and age- and sex-matched healthy controls. Compared with healthy controls, the percentage of perforin-expressing CD3-CD56+ NK cells quantified by flow cytometry was low in COVID-19 patients (69.9 ± 17.7 versus 78.6 ± 14.6%, p = 0.026). There was no correlation between the proportions of perforin-positive NK cells and T8 lymphocytes. Moreover, the frequency of NK cells producing perforin was neither linked to disease severity nor predictive of death. Although IL-6 is known to downregulate perforin production in NK cells, we did not find any link between perforin expression and IL-6 plasma level. However, we unveiled a negative correlation between the degranulation marker CD107a and perforin expression in NK cells (r = -0.488, p = 10-4). PRF1 gene expression and the frequency of NK cells harboring perforin were normal in patients 1 y after acute SARS-CoV-2 infection. A primary perforin defect does not seem to be a driver of COVID-19 because NK perforin expression is 1) linked neither to T8 perforin expression nor to disease severity, 2) inversely correlated with NK degranulation, and 3) normalized at distance from acute infection. Thus, the cause of low frequency of perforin-positive NK cells appears, rather, to be consumption.

Unveiling the intricacies of COVID-19: Autoimmunity, multi-organ manifestations and the role of autoantibodies

COVID-19 is a severe infectious disease caused by a SARS-CoV-2 infection. It has caused a global pandemic and can lead to acute respiratory distress syndrome (ARDS). Beyond the respiratory system, the disease manifests in multiple organs, producing a spectrum of clinical symptoms. A pivotal factor in the disease's progression is autoimmunity, which intensifies its severity and contributes to multi-organ injuries. The intricate interaction between the virus' spike protein and human proteins may engender the generation of autoreactive antibodies through molecular mimicry. This can further convolute the immune response, with the potential to escalate into overt autoimmunity. There is also emerging evidence to suggest that COVID-19 vaccinations might elicit analogous autoimmune responses. Advanced technologies have pinpointed self-reactive antibodies that target diverse organs or immune-modulatory proteins. The interplay between autoantibody levels and multi-organ manifestations underscores the importance of regular monitoring of serum antibodies and proinflammatory markers. A combination of immunosuppressive treatments and antiviral therapy is crucial for managing COVID-19-associated autoimmune diseases. The review will focus on the generation of autoantibodies in the context of COVID-19 and their impact on organ health.

Kinetics of IL-6, C-reactive Protein and Fibrinogen Levels in COVID-19 Outpatients Who Evolved to Hypoxemia

Introduction

Despite the efficacy of the COVID-19, the search for improvements in the management of severe/critical cases continues to be important. The aim is to demonstrate the kinetics of 4 serological markers in patients with COVID-19 who evolved in hypoxemia.

Methods

From June to December 2020, the Health Secretariat of Rondônia State, Brazil, established a home medical care service team (HMCS) that provided clinical follow-up for health professionals and military personnel with COVID-19. The clinical and laboratory monitoring was individualized at home by a nursing and medical team. In addition to laboratory parameters, C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, and D-dimer levels were periodically taken to monitor the evolution of treatment.

Results

Of 218 patients telemonitored, 48 patients needed special care by the HMCS team due to shortness of breath. Chest tomography showed multiple ground-glass shadows and lung parenchymal condensations that was compatible with secondary bacterial infection associated with leukocytosis, for which antibiotics were prescribed. The symptoms were accompanied by increases of CRP and IL-6 levels followed by fibrinogen after a few days, for which an anticoagulant therapy was included. Thirty-three patients evolved to improvements in clinical signs and laboratory results. Between the sixth and eighth day of illness, 15 patients presented signs of hypoxemia with low O2 saturation accompanied with an increase in the respiratory rate, with some of them requiring oxygen therapy. As they did not present signs of clinical severity, but their laboratory markers showed an abrupt IL-6 peak that was higher than the increase in CRP and a new alteration in fibrinogen levels, they received a supplemental dose of anticoagulant and a high dose of corticosteroids, which resulted in clinical improvement.

Conclusion

Our study demonstrates that monitoring of IL-6 and CRP may identify precocious hypoxemia in COVID-19 patients and prevented the progressive deterioration of the lung injury.

Clinical characteristics of hemophagocytic lymphohistiocytosis

BACKGROUND

There is no specificity in the clinical presentation of hemophagocytic lymphohistiocytosis (HLH).

OBJECTIVE

To study some clinical, etiological, and prognostic features of HLH to improve the clinical understanding of the disease.

METHODS

Retrospective analysis of the clinical data of 125 patients with HLH admitted to our hospital from June 2015 to August 2021, including clinical characteristics, laboratory indicators, and survival period. Statistical analysis was performed from the overall group of study indicators, which included population, children, and adults.

RESULTS

In the whole population, sex, age, blood myoglobin, and NK cell ratio of M-HLH and non-M-HLH patients (P< 0.05), serum albumin, and direct bilirubin were independent correlates of M-HLH. In the pediatric group, age and the proportion of NK cells were significantly different between M-HLH and non-M-HLH patients (P< 0.05). Multivariate Logistic regression analysis showed that all factors were not significantly associated with M-HLH. The associated regression analysis showed that all factors were not significantly associated with M-HLH. ROC curve analysis showed that the best predictive value of NK cell percentage for M-HLH diagnosis in the overall population was 4.96% in the pediatric group and 4.96% in the adult group. The best predictive value for M-HLH diagnosis was 2.08%. The univariate analysis showed that platelet count, alanine aminotransferase, aspartate aminotransferase, serum albumin, direct bilirubin and indirect bilirubin affected prognosis; COX regression showed that none of these factors had a significant relationship. The overall median survival time was 20.7 months in the adult group, 44.3 months in non-M-HLH patients, and 7.73 months in M-HLH patients (p= 0.011); univariate analysis showed that platelet count and serum albumin level affected prognosis; COX regression results in serum albumin level was an independent risk factor for prognosis.

CONCLUSION

The survival rate of non-M-HLH was significantly better than that of M-HLH; the proportion of NK cells had predictive value for the diagnosis of M-HLH; in the general population, non-M-HLH was more likely to have abnormal liver function than M-HLH: lower platelet count and serum albumin level were associated with poor prognosis, and the lower the platelet count and serum albumin level, the worse the prognosis: in addition, adults with lower serum albumin levels are also associated with poor prognosis.

Bone marrow haematopoiesis in patients with COVID-19

AIMS

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection broadly affects organ homeostasis, including the haematopoietic system. Autopsy studies are a crucial tool for investigation of organ-specific pathologies. Here we perform an in-depth analysis of the impact of severe coronavirus disease 2019 (COVID-19) on bone marrow haematopoiesis in correlation with clinical and laboratory parameters.

METHODS AND RESULTS

Twenty-eight autopsy cases and five controls from two academic centres were included in the study. We performed a comprehensive analysis of bone marrow pathology and microenvironment features with clinical and laboratory parameters and assessed SARS-CoV-2 infection of the bone marrow by quantitative polymerase chain reaction (qPCR) analysis. In COVID-19 patients, bone marrow specimens showed a left-shifted myelopoiesis (19 of 28, 64%), increased myeloid-erythroid ratio (eight of 28, 28%), increased megakaryopoiesis (six of 28, 21%) and lymphocytosis (four of 28, 14%). Strikingly, a high proportion of COVID-19 specimens showed erythrophagocytosis (15 of 28, 54%) and the presence of siderophages (11 of 15, 73%) compared to control cases (none of five, 0%). Clinically, erythrophagocytosis correlated with lower haemoglobin levels and was more frequently observed in patients from the second wave. Analysis of the immune environment showed a strong increase in CD68+ macrophages (16 of 28, 57%) and a borderline lymphocytosis (five of 28, 18%). The stromal microenvironment showed oedema (two of 28, 7%) and severe capillary congestion (one of 28, 4%) in isolated cases. No stromal fibrosis or microvascular thrombosis was found. While all cases had confirmed positive testing of SARS-CoV-2 in the respiratory system, SARS-CoV-2 was not detected in the bone marrow by high-sensitivity PCR, suggesting that SARS-CoV-2 does not commonly replicate in the haematopoietic microenvironment.

CONCLUSIONS

SARS-CoV-2 infection indirectly impacts the haematological compartment and the bone marrow immune environment. Erythrophagocytosis is frequent and associated with lower haemoglobin levels in patients with severe COVID-19.

SFTSV infection is associated with transient overproliferation of monoclonal lambda-type plasma cells

The impairment of antibody-mediated immunity is a major factor associated with fatal cases of severe fever with thrombocytopenia syndrome (SFTS). By collating the clinical diagnosis reports of 30 SFTS cases, we discovered the overproliferation of monoclonal plasma cells (MCP cells, CD38⁺cLambda⁺cKappa^-) in bone marrow, which has only been reported previously in multiple myeloma. The ratio of CD38⁺cLambda⁺ versus CD38⁺cKappa⁺ in SFTS cases with MCP cells was significantly higher than that in normal cases. MCP cells presented transient expression in the bone marrow, which was distinctly different from multiple myeloma. Moreover, the SFTS patients with MCP cells had higher clinical severity. Further, the overproliferation of MCP cells was also observed in SFTS virus (SFTSV)-infected mice with lethal infectious doses. Together, SFTSV infection induces transient overproliferation of monoclonal lambda-type plasma cells, which have important implications for the study of SFTSV pathogenesis, prognosis, and the rational development of therapeutics.

A prospective, single-center, randomized phase 2 trial of etoposide in severe COVID-19

The systemic inflammatory response seen in patients with severe COVID-19 shares many similarities with the changes observed in hemophagocytic lymphohistiocytosis (HLH); a disease characterized by excessive immune activation. Many patients with severe COVID qualify for a diagnosis of HLH. Etoposide, an inhibitor of topoisomerase II is used to control inflammation in HLH. This randomized, open-label, single center phase II trial attempted to determine whether etoposide can be used to blunt the inflammatory response in severe COVID. This trial was closed early after eight patients were randomized. This underpowered trial did not meet its primary endpoint of improvement in pulmonary status by two categories on an 8 point ordinal scale of respiratory function. There were not significant differences in secondary outcomes including overall survival at 30 days, cumulative incidence of grade 2 through 4 adverse events during hospitalization, duration of hospitalization, duration of ventilation and improvement in oxygenation or paO2/FIO2 ratio or improvement in inflammatory markers associated with cytokine storm. A high rate of grade 3 myelosuppression was noted in this critically ill population despite dose reduction, a toxicity which will limit future attempts to explore the utility of etoposide for virally-driven cytokine storm or HLH.

Coronavirus Does It Again: Post-COVID-19 Hemophagocytic Lymphohistiocytosis (HLH)

Hemophagocytic lymphohistiocytosis (HLH) is a hematological disorder that results from an uncontrolled activation of the immune system, which can then lead to multisystem organ failure. Given the nonspecific nature of this illness, it can go undetected for too long, thereby causing permanent damage to organ systems. In adults, HLH has been associated with a number of infectious etiologies, particularly viral infections. Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to a global pandemic and has been associated with acute respiratory distress syndrome (ARDS). Among its other manifestations, COVID-19 has also been linked to HLH. In this report, we describe a case of a male patient who presented with multisystem organ failure and was found to have HLH. Since no clear etiology for his HLH could be elicited, it was determined to be a result of his recent COVID-19 infection.

"A Dangerous Black Box:" Idiopathic Hemophagocytic Lymphohistiocytosis in Adult Patients-A Case Report and Review of the Literature

Hemophagocytic lymphohistiocytosis (HLH) is a rare potentially life-threatening condition characterized by aberrant inflammation that can be related to genetic or sporadic forms. In both forms, triggering factors may be involved. Early detection of the underlying cause is crucial for therapeutic decision, while early intervention might be associated with better outcomes. The largest descriptions in the literature on HLH refer to pediatric cases. Adolescents and adults may also be affected, but there is scarce evidence regarding their diagnosis and management. We describe here the case of a 68-year-old Swiss woman with HLH, in whom an extensive search for underlying causes was performed, but neither trigger nor pathogenic variant was found. An early intervention first with dexamethasone and later with cyclosporine was performed. The patient showed a favorable response and did not require further hospitalization; however, one year after diagnosis, it was not possible to suspend cyclosporine due to recurrence of laboratory inflammation signs by drug tapering. The occurrence of HLH idiopathic forms represents a challenge; failure to identify the underlying triggering cause generates uncertainty, endless diagnostic investigations, and consequently additional delays in the treatment. This manuscript addresses the difficulties on this issue.

Fatal Hemophagocytic Lymphohistiocytosis in a Patient with Miliary Tuberculosis: a Case Report

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome induced by cytotoxic T-cells. Mostly, HLH is secondary to infections, malignancies, or autoimmune disorders. HLH triggered by miliary tuberculosis is rare and mortality rates are high. We report a case of a 58-year-old, Caucasian patient admitted to the ICU with respiratory failure. After extensive tests, the diagnosis of HLH was made. Despite aggressive treatment with antibiotics, etoposide, anakinra, and tocilizumab, our patient succumbed to the illness after 18 days in the ICU. Postmortem, a diagnosis of miliary tuberculosis was made, despite negative PCR and culture of mycobacteria during clinical course. Our case demonstrates the challenges of early diagnosis of HLH and the importance of considering miliary tuberculosis as a possible underlying trigger.

Common bone marrow signature in COVID-19-associated multisystem inflammatory syndrome in children: A first-wave small case series experience

The hyper-inflammatory response, also known as multisystem inflammatory syndrome in children (MIS-C), represents a major concern in children with SARS-CoV-2 infection. We report bone marrow features of three patients with MIS-C who were diagnosed during the first wave of the SARS-CoV-2 pandemic. A bone marrow evaluation was performed at onset of the inflammatory condition in order to exclude secondary hemophagocytic lymphohistiocytosis (sHLH). The bone marrows of the patients presented common features: the erythroid and megakaryocytic lineages were prominently affected and hemophagocytosis was moderately increased, differently than observed in sHLH. Megakaryocytopoiesis was increased, representing a peculiar feature of MIS-C differing from sHLH. SARS-CoV-2 RT-PCR and viral panel were studied in bone marrow aspiration samples. MIS-C is a rare complication of SARS-CoV-2 infections in children. An immuno-dysregulation considering both innate and adaptive immunity together with vascular inflammation and endothelial dysfunction play a major role. Our observations, although limited due to the small sample size, suggest that there are unique features in the bone marrow of patients with MIS-C that are likely secondary to immuno-dysregulation, and there are notable differences in bone marrow features compared to those reported in sHLH.

Potential histopathological and immunological effects of SARS-CoV-2 on the liver

The coronavirus disease outbreak of 2019 (COVID-19) poses a serious threat to public health worldwide. Lung injury is the most common complication of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. However, other organs, including the liver, can also be affected. Currently, there is limited evidence that liver impairment is associated with severe SARS-CoV-2 infection. Clinicians will need to determine whether liver injury is caused by an underlying liver condition, COVID-19 therapy, the virus directly, or immune-mediated inflammation or represents a complicated disease course in the context of COVID-19. To address the scarcity of data on histopathological changes and immunological effects on the liver with COVID-19 positivity, we analyze and summarize recent findings. We searched PubMed, Medline, Google Scholar, Science Direct, Scopus, and Web of Science databases up to December 1, 2021, identifying published studies with the search terms "Histopathology in COVID-19," "COVID-19," "Pathological changes in liver in COVID-19," "Liver pathology in COVID-19," "immunological effects in liver in COVID-19," and "SARS-CoV-2." This concise review will aid clinicians and researchers in better understanding the tissue histopathology and immunological consequences of SARS-CoV-2 on the liver, enabling improved care planning and avoiding future dangers.

Case Report: Secondary Hemophagocytic Lymphohistiocytosis (sHLH) and Candida auris Fungemia in Post-acute COVID-19 Syndrome: A Clinical Challenge

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes a disease (COVID-19) with multisystem involvement. The world is now entering a phase of post-COVID-19 manifestations in this pandemic. Secondary hemophagocytic lymphohistiocytosis (sHLH) is a life-threatening hyperinflammatory event triggered by viral infections, including SARS-CoV-2. Both Multisystem Inflammatory Syndrome-Adults (MIS-A) and Cytokine Storm Syndrome (CSS) are considered close differentials of sHLH and add to the spectrum of Post-acute COVID-19 syndrome (PACS). In this report, we presented the case of a middle-aged Asian man who was initially discharged upon recovery from severe COVID-19 infection after 17 days of hospitalization to a private institute and later came to our hospital 13 days post-discharge. Here, he was diagnosed with sHLH, occurring as an extension of CSS, with delayed presentation falling within the spectrum of PACS. The diagnosis of sHLH was made holistically with the HLH-2004 criteria. Our patient initially responded to intravenous immunoglobulin (IVIG) and dexamethasone, later complicated by disseminated Candida auris infection and had a fatal outcome. Though many cases of HLH during active COVID-19 and a few cases post COVID-19 recovery have been reported, based on H-score, which has limitations as a diagnostic tool. We report the first case report of post-COVID-19 sHLH using the HLH-2004 criteria, complicated by disseminated Candidemia, emphasizing that the care of patients with COVID-19 does not conclude at the time of hospital discharge. We highlight the importance of surveillance in the post-COVID phase for early detection of sHLH which may predispose to fatal opportunistic infections (OIs).

Hemophagocytic lymphohistiocytosis diagnosed by bone marrow trephine biopsy in living post-COVID-19 patients: case report and mini-review

Hemophagocytic lymphohistiocytosis (HLH) constitutes a life-threatening inflammatory syndrome. Postmortem histological findings of bone marrow (BM) from COVID-19 patients showed histiocytosis and hemophagocytosis and supported the hypothesis that secondary HLH (sHLH) may be triggered by SARS-CoV-2 infection. However, there are a limited number of sHLH cases in which trephine has been performed in living post-COVID-19 patients. Here we present a recent case and a mini-review of sHLH diagnosed by trephine biopsy in living patients after COVID-19. An 81-year-old man with a past medical history of hypertension, diabetes, ischemic stroke, was referred to the hospital to evaluate leukocytosis, pyuria, and elevation of inflammatory markers four weeks after recovering from COVID-19. Computed tomography of the abdomen did not reveal focal signs of infection or hepatosplenomegaly. The patient received intravenous meropenem and two packed red blood cell units. Leukocytes and C-reactive protein were gradually decreased. A BM biopsy was performed and the patient was discharged on cefixime. BM smear revealed severe anemia, lymphopenia, and dysplastic morphologic findings of erythroblasts, neutrophils, and megakaryocytes. Trephine biopsy revealed hypercellular marrow dyserythropoiesis, plasmacytosis, lymphocytosis, histiocytosis, hemophagocytosis, and the absence of granulomas or carcinoma. Immunohistochemistry documented a mixed population of T lymphocytes (CD3+) and B lymphocytes (CD20+). Strong positivity for CD68 confirmed histiocytosis. CD138 κ, λ staining proved polyclonal plasmacytosis. Perl’s staining showed excess hemosiderin deposits. Based on our findings, we document sHLH in trephine BM biopsy of a living post-COVID-19 patient and persistent leukocytosis, underscoring the diagnostic value of trephine biopsy in preventing life-threatening conditions such as COVID-19.

Histopathological Findings in COVID-19 Cases: A Systematic Review

The ongoing coronavirus disease 2019 (COVID-19) pandemic has turned into one of the most serious public health crises of the last few decades. Although the disease can result in diverse and multiorgan pathologies, very few studies have addressed the postmortem pathological findings of COVID-19 cases. Active autopsy findings amid this pandemic could be an essential tool for diagnosis, surveillance, and research. We aimed to provide a comprehensive picture of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) histopathological features of different body organs through a systematic review of the published literature. A systematic search of electronic databases (PubMed, ScienceDirect, Google Scholar, medRxiv, and bioRxiv) for journal articles of different study designs reporting postmortem pathological findings in COVID-19 cases was performed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for conducting the review. A total of 50 articles reporting 430 cases were included in our analysis. Postmortem pathological findings were reported for different body organs: pulmonary system (42 articles), cardiovascular system (23 articles), hepatobiliary system (22 articles), kidney (16 articles), spleen and lymph nodes (12 articles), and central nervous system (seven articles). In lung samples, diffuse alveolar damage (DAD) was the most commonly reported finding in 239 cases (84.4%). Myocardial hypertrophy (87 cases, 51.2%), arteriosclerosis (121 cases, 62%), and steatosis (118 cases, 59.3%) were the most commonly reported pathological findings in the heart, kidney, and the hepatobiliary system respectively. Autopsy examination as an investigation tool could lead to a better understanding of SARS-CoV-2 pathophysiology, diagnosis, and management, subsequently improving patient care.

Secondary haemophagocytic lymphohistiocytosis in COVID-19: correlation of the autopsy findings of bone marrow haemophagocytosis with HScore

BACKGROUND

Secondary haemophagocytic lymphohistiocytosis (sHLH) is characterised by a hyper activation of immune system that leads to multiorgan failure. It is suggested that excessive immune response in patients with COVID-19 could mimic this syndrome. Some COVID-19 autopsy studies have revealed the presence of haemophagocytosis images in bone marrow, raising the possibility, along with HScore parameters, of sHLH.

AIM

Our objective is to ascertain the existence of sHLH in some patients with severe COVID-19.

METHODS

We report the autopsy histological findings of 16 patients with COVID-19, focusing on the presence of haemophagocytosis in bone marrow, obtained from rib squeeze and integrating these findings with HScore parameters. CD68 immunohistochemical stains were used to highlight histiocytes and haemophagocytic cells. Clinical evolution and laboratory parameters of patients were collected from electronic clinical records.

RESULTS

Eleven patients (68.7%) displayed moderate histiocytic hyperplasia with haemophagocytosis (HHH) in bone marrow, three patients (18.7%) displayed severe HHH and the remainder were mild. All HScore parameters were collected in 10 patients (62.5%). Among the patients in which all parameters were evaluable, eight patients (80%) had an HScore >169. sHLH was not clinically suspected in any case.

CONCLUSIONS

Our results support the recommendation of some authors to use the HScore in patients with severe COVID-19 in order to identify those who could benefit from immunosuppressive therapies. The presence of haemophagocytosis in bone marrow tissue, despite not being a specific finding, has proved to be a very useful tool in our study to identify these patients.

A rare case of COVID-19 pneumonia with severe hyperlipoproteinemia

A 55-year-old woman was admitted to our hospital for coronavirus disease 2019 (COVID-19) pneumonia. Her symptoms improved upon treatment with steroids, remdesivir and heparin. After discharge, she consumed excessive alcohol because of taste disorder due to COVID-19; she also had chylomicronemia with a triglyceride (TG) level of 8750 mg/dl. Chylomicrons and very-low-density lipoprotein were detected by electrophoresis, and she was diagnosed with severe hyperlipoproteinemia, suspected to be Type V hyperlipoproteinemia. She did not have any symptoms of pancreatitis, and her TG levels decreased with fat intake restriction and sobriety. This is a rare case of COVID-19 with hyperlipoproteinemia, and the causes of hyperlipoproteinemia might be associated with COVID-19 complications, steroids and/or lifestyle changes during the pandemic; therefore, changes in TGs should be observed carefully after the resolution of COVID-19.

JAK inhibitors and COVID-19

During SARS-CoV-2 infection, the innate immune response can be inhibited or delayed, and the subsequent persistent viral replication can induce emergency signals that may culminate in a cytokine storm contributing to the severe evolution of COVID-19. Cytokines are key regulators of the immune response and virus clearance, and, as such, are linked to the—possibly altered—response to the SARS-CoV-2. They act via a family of more than 40 transmembrane receptors that are coupled to one or several of the 4 Janus kinases (JAKs) coded by the human genome, namely JAK1, JAK2, JAK3, and TYK2. Once activated, JAKs act on pathways for either survival, proliferation, differentiation, immune regulation or, in the case of type I interferons, antiviral and antiproliferative effects. Studies of graft-versus-host and systemic rheumatic diseases indicated that JAK inhibitors (JAKi) exert immunosuppressive effects that are non-redundant with those of corticotherapy. Therefore, they hold the potential to cut-off pathological reactions in COVID-19. Significant clinical experience already exists with several JAKi in COVID-19, such as baricitinib, ruxolitinib, tofacitinib, and nezulcitinib, which were suggested by a meta-analysis (Patoulias et al.) to exert a benefit in terms of risk reduction concerning major outcomes when added to standard of care in patients with COVID-19. Yet, only baricitinib is recommended in first line for severe COVID-19 treatment by the WHO, as it is the only JAKi that has proven efficient to reduce mortality in individual randomized clinical trials (RCT), especially the Adaptive COVID-19 Treatment Trial (ACTT-2) and COV-BARRIER phase 3 trials. As for secondary effects of JAKi treatment, the main caution with baricitinib consists in the induced immunosuppression as long-term side effects should not be an issue in patients treated for COVID-19.

We discuss whether a class effect of JAKi may be emerging in COVID-19 treatment, although at the moment the convincing data are for baricitinib only. Given the key role of JAK1 in both type I IFN action and signaling by cytokines involved in pathogenic effects, establishing the precise timing of treatment will be very important in future trials, along with the control of viral replication by associating antiviral molecules.

Organ manifestations of COVID-19: what have we learned so far (not only) from autopsies?

The use of autopsies in medicine has been declining. The COVID-19 pandemic has documented and rejuvenated the importance of autopsies as a tool of modern medicine. In this review, we discuss the various autopsy techniques, the applicability of modern analytical methods to understand the pathophysiology of COVID-19, the major pathological organ findings, limitations or current studies, and open questions. This article summarizes published literature and the consented experience of the nationwide network of clinical, neuro-, and forensic pathologists from 27 German autopsy centers with more than 1200 COVID-19 autopsies. The autopsy tissues revealed that SARS-CoV-2 can be found in virtually all human organs and tissues, and the majority of cells. Autopsies have revealed the organ and tissue tropism of SARS-CoV-2, and the morphological features of COVID-19. This is characterized by diffuse alveolar damage, combined with angiocentric disease, which in turn is characterized by endothelial dysfunction, vascular inflammation, (micro-) thrombosis, vasoconstriction, and intussusceptive angiogenesis. These findings explained the increased pulmonary resistance in COVID-19 and supported the recommendations for antithrombotic treatment in COVID-19. In contrast, in extra-respiratory organs, pathological changes are often nonspecific and unclear to which extent these changes are due to direct infection vs. indirect/secondary mechanisms of organ injury, or a combination thereof. Ongoing research using autopsies aims at answering questions on disease mechanisms, e.g., focusing on variants of concern, and future challenges, such as post-COVID conditions. Autopsies are an invaluable tool in medicine and national and international interdisciplinary collaborative autopsy-based research initiatives are essential.

Hemophagocytic Lymphohistiocytosis Gene Variants in Multisystem Inflammatory Syndrome in Children

Simple Summary

Children with a COVID-19 infection are at risk of developing a novel syndrome called multisystem inflammatory syndrome in children (MIS-C). This disease state is characterized by a high level of inflammation. It is unclear why only some children infected with SARS-CoV-2 later develop MIS-C. There may be genetic risk factors for MIS-C development, but none have previously been reported. We report genetic findings in a group of children with MIS-C.

Abstract

Multisystem inflammatory syndrome in children (MIS-C) affects few children previously infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In 2020, 45 children admitted to our hospital for MIS-C underwent genetic screening with a commercial 109-immune-gene panel. Thirty-nine children were diagnosed with MIS-C, and 25.4% of the 39 MIS-C patients harbored rare heterozygous missense mutations either in primary hemophagocytic lymphohistiocytosis (pHLH) genes (LYST, STXBP2, PRF1, UNC13D, AP3B1) or the HLH-associated gene DOCK8 (four variants). We demonstrate that foamy virus introduction of cDNA for the four DOCK8 variants into human NK-92 natural killer (NK) cells led to decreased CD107a expression (degranulation) and decreased NK cell lytic function in vitro for each variant. Heterozygous carriers of missense mutations in pHLH genes and DOCK8 may serve as risk factors for development of MIS-C among children previously infected with SARS-CoV-2.

Secondary Hemophagocytic Lymphohistiocytosis in a Post-COVID-19 Patient

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening condition caused by excessive immune system activation. HLH can be primary or secondary. Primary HLH is commonly seen in children with underlying genetic mutations, while secondary HLH can be seen at any age. It is usually triggered by inciting factors such as viral infections, patients with underlying rheumatological disease, or malignancies. It has very poor prognosis if left untreated, with survival of only a few months. While there have been around 100 cases of HLH reported during the acute phase of COVID-19 infection, very few post-COVID-19 HLH cases have been reported, only around 35 cases. Here we report a case of a 20-year-old Caucasian male who presented eight weeks after COVID-19 infection with extreme fatigue, fever, lab work concerning for HLH, and a high H score indicating a high probability of HLH. Early identification of HLH following COVID-19 recovery would allow for timely management of the condition.

Is COVID-19-associated cytokine storm distinct from non-COVID-19 secondary hemophagocytic lymphohistiocytosis?

Cytokine storm is an umbrella term that describes an inflammatory syndrome characterized by elevated levels of circulating cytokines and hyperactivation of innate and/or adaptive immune cells. One type of cytokine storm is hemophagocytic lymphohistiocytosis (HLH), which can be either primary or secondary. Severe COVID-19-associated pneumonia and acute respiratory distress syndrome (ARDS) can also lead to cytokine storm/cytokine release syndrome (CS/CRS) and, more rarely, meet criteria for the diagnosis of secondary HLH. Here, we review the immunobiology of primary and secondary HLH and examine whether COVID-19-associated CS/CRS can be discriminated from non-COVID-19 secondary HLH. Finally, we review differences in immunobiology between these different entities, which may inform both clinical diagnosis and treatment of patients.

Hemophagocytic Lymphohistiocytosis and Infection: A Literature Review

Hemophagocytic lymphocytosis (HLH) is a life-threatening, underdiagnosed syndrome caused by the excessive release of inflammatory mediators. Primary lymphocytosis is usually seen in young children and is associated with genetic defects, while secondary lymphocytosis is presented in adults due to malignancy, rheumatic disease, or infection. The aim of this study is to describe the infectious agents that trigger HLH in the adult population and provide diagnostic and treatment guidelines for this life-threatening syndrome. We conducted a literature review using PubMed as our basic database. We collected papers from the past six years that studied infectious agents that triggered HLH and described the most recommended treatment options for this serious condition. A total of 32 studies were included for this literature review.HLH is considered a syndrome with variable symptoms, and clinicians should be familiar with its complexity and the pathologies that could contribute to its presentation. Collaboration between physicians and awareness are basic steps for the management of patients with HLH.

SARS-CoV-2 (COVID-19) pneumonia patient treated with two doses of infliximab within 2 weeks for acute severe ulcerative colitis: A case report

RATIONALE

The ongoing coronavirus pandemic has caused severe acute respiratory syndrome, posing a significant challenge for patients receiving immunotherapy for immune-mediated inflammatory diseases. As of January 2022, immunosuppressants such as tumor necrosis factor inhibitors (anti-TNFα) and azathioprine are inadvisable for an infectious disease caused by the SARS-CoV-2 virus (COVID-19). We continued infliximab as a second induction dose nine days after the onset of COVID-19 symptoms in a patient with acute severe ulcerative colitis.

PATIENT CONCERNS

We report the case of a 34-year-old male with 6 to 8 times bloody diarrhea, fever, and cramping abdominal pain. Ulcerative colitis was diagnosed 6 months earlier and treated with mesalamine 80 mg/kg/day and azathioprine 2.5 mg/kg/day. The patient had never undergone surgery before. Sigmoidoscopy revealed multiple ulcerations and spontaneous bleeding, and the colon samples tested negative for cytomegalovirus and Clostridium difficile. However, intravenous corticosteroids did not induce remission. A nasopharyngeal swab tested positive for SARS-CoV-2.

DIAGNOSIS

Acute severe ulcerative colitis and SARS-CoV-2 (COVID-19) pneumonia.

INTERVENTIONS

The second loading dose of infliximab was administered nine days after the diagnosis of COVID-19.

OUTCOME

The patient completed infliximab induction at a dose of 5 mg/kg at weeks 0, 2, and 6, with no complications.

LESSONS

It is unclear whether anti-TNF-α treatment improves or deteriorates COVID-19 patient outcomes, and this case demonstrates that infliximab can be used safely. Current guidelines make a weak recommendation to avoid using anti-TNFα agents in the presence of acute COVID-19 infection. There is an urgent need for research on biologics therapy.

Innate immunological pathways in COVID-19 pathogenesis

[Figure: see text].

Findings and inferences from full autopsies, minimally invasive autopsies and biopsy studies in patients who died as a result of COVID19 - A systematic review

Many articles on COVID19 deaths have been published since the pandemic has occurred. On reviewing the articles published until June 2021, the findings were very heterogeneous. Adding to the existing knowledge, there were also some unique observations made in the pathogenesis of COVID19. This review was done to determine the findings obtained and inferences drawn from various studies published globally among patients who died due to COVID19. PRISMA guidelines were used to conduct this systematic review. A search of databases like PubMed, ScienceDirect and Epistemonikos was done. The articles focusing on postmortem sample studies involving full autopsies, minimally invasive autopsies and tissue biopsy studies were screened and searched. The studies included were all the case reports, case series, narrative reviews and systematic reviews obtained in full text and in the English language containing study information, and samples obtained postmortem. The information obtained was tabulated using Microsoft excel sheets. The duplicates were removed at the beginning of the tabulation. Zotero referencing software was used for article sorting and citation and bibliography. Two authors independently reviewed the articles throughout the process to prevent bias. Adding to the heterogeneity of COVID19, the concept of lethality in preexisting disease conditions, the occurrence of secondary bacterial and fungal infections, and other pathogenetic mechanisms uniquely encountered are to be considered in treating the patients. Also, the presence of SARS-CoV-2 postmortem is established and should be considered a hazard.

Minimally Invasive Tissue Sampling as an Alternative to Complete Diagnostic Autopsies in the Context of Epidemic Outbreaks and Pandemics: The Example of Coronavirus Disease 2019 (COVID-19)

Background

Infectious diseases’ outbreak investigation requires, by definition, conducting a thorough epidemiological assessment while simultaneously obtaining biological samples for an adequate screening of potential responsible pathogens. Complete autopsies remain the gold-standard approach for cause-of-death evaluation and characterization of emerging diseases. However, for highly transmissible infections with a significant associated lethality, such as COVID-19, complete autopsies are seldom performed due to biosafety challenges, especially in low-resource settings. Minimally invasive tissue sampling (MITS) is a validated new approach based on obtaining postmortem samples from key organs and body fluids, a procedure that does not require advanced biosafety measures or a special autopsy room.

Methods

We aimed to review the use of MITS or similar procedures for outbreak investigation up to 27 March 2021 and their performance for evaluating COVID-19 deaths.

Results

After a literature review, we analyzed in detail the results of 20 studies conducted at international sites, whereby 216 COVID-19–related deaths were investigated. MITS provided a general and more granular understanding of the pathophysiological changes secondary to the infection and high-quality samples where the extent and degree of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–related damage could be evaluated.

Conclusions

MITS is a useful addition in the investigation and surveillance of infections occurring in outbreaks or epidemics. Its less invasive nature makes the tool more acceptable and feasible and reduces the risk of procedure-associated contagion, using basic biosafety measures. Standardized approaches protocolizing which samples should be collected—and under which exact biosafety measures—are necessary to facilitate and expand its use globally.

Hemphagocytic Lymphohistiocytosis Secondary to COVID-19: A Case Report

Hemophagocytic lymphohistiocytosis (HLH) is categorized into primary HLH and secondary HLH. Primary or familial HLH is an autosomal recessive disorder due to mutation in immune regulatory genes. Secondary HLH is an uncommon hyperinflammatory disease triggered by a critical illness (malignancies or viral infection) that induces an uncontrollable excessive immune response, which results in multiorgan failure. Due to the rarity of the syndrome, HLH is associated with worse outcomes. Severe coronavirus disease-19 (COVID-19) is identified as a trigger of HLH, and published literature suggests that patients with severe COVID-19 are at high risk of developing HLH. COVID-19-associated HLH is rarely reported in the literature. Herein we present a case of secondary HLH due to COVID-19 presented in the emergency department with prolonged non-resolving fever.

Vascular Damage, Thromboinflammation, Plasmablast Activation, T-Cell Dysregulation and Pathological Histiocytic Response in Pulmonary Draining Lymph Nodes of COVID-19

Although initial immunophenotypical studies on peripheral blood and bronchoalveolar lavage samples have provided a glimpse into the immunopathology of COVID-19, analyses of pulmonary draining lymph nodes are currently scarce. 22 lethal COVID-19 cases and 28 controls were enrolled in this study. Pulmonary draining lymph nodes (mediastinal, tracheal, peribronchial) were collected at autopsy. Control lymph nodes were selected from a range of histomorphological sequelae [unremarkable histology, infectious mononucleosis, follicular hyperplasia, non-SARS related HLH, extrafollicular plasmablast activation, non-SARS related diffuse alveolar damage (DAD), pneumonia]. Samples were mounted on a tissue microarray and underwent immunohistochemical staining for a selection of immunological markers and in-situ hybridization for Epstein Barr Virus (EBV) and SARS-CoV-2. Gene expression profiling was performed using the HTG EdgeSeq Immune Response Panel. Characteristic patterns of a dysregulated immune response were detected in COVID-19: 1. An accumulation of extrafollicular plasmablasts with a relative paucity or depletion of germinal centers. 2. Evidence of T-cell dysregulation demonstrated by immunohistochemical paucity of FOXP3+, Tbet+ and LEF1+ positive T-cells and a downregulation of key genes responsible for T-cell crosstalk, maturation and migration as well as a reactivation of herpes viruses in 6 COVID-19 lymph nodes (EBV, HSV). 3. Macrophage activation by a M2-polarized, CD163+ phenotype and increased incidence of hemophagocytic activity. 4. Microvascular dysfunction, evidenced by an upregulation of hemostatic (CD36, PROCR, VWF) and proangiogenic (FLT1, TEK) genes and an increase of fibrin microthrombi and CD105+ microvessels. Taken together, these findings imply widespread dysregulation of both innate and adoptive pathways with concordant microvascular dysfunction in severe COVID-19.

Neutropenic Fever in a Patient With SARS-CoV-2-Induced Hemophagocytic Lymphohistiocytosis (HLH)

Hemophagocytic lymphohistiocytosis (HLH) is a severe systemic inflammatory syndrome that is often fatal. In the adult population, it is believed to develop secondary to immune dysregulation due to rheumatologic, infectious, malignant, and recently, immunomodulatory drugs. It has been well documented that infectious etiologies can lead to HLH however to date there is a paucity of case reports of HLH stemming from the 2019 novel coronavirus (SARS-CoV-2). Furthermore, it is well established that overlap exists between the extensive hyper-inflammatory syndromes produced from both HLH and severe COVID-19 infection. Here, we present a case of COVID-19-associated HLH with recurrent neutropenic fever in a patient with controlled follicular non-Hodgkin lymphoma who received treatment with etoposide after continued hospital admissions with refractory medical treatment.

Common points of therapeutic intervention in COVID-19 and in allogeneic hematopoietic stem cell transplantation associated severe cytokine release syndrome

Allogeneic hematopoietic stem cell transplantation (HSCT) and coronavirus disease 2019 (COVID-19) infection can both lead to severe cytokine release syndrome (sCRS) resulting in critical illness and death. In this single institution, preliminary comparative case-series study we compared clinical and laboratory co-variates as well as response to tocilizumab (TCZ)-based therapy of 15 allogeneic-HSCT- and 17 COVID-19-associated sCRS patients. Reaction to a TCZ plus posttransplant cyclophosphamide (PTCY) consolidation therapy in the allogeneic-HSCT-associated sCRS group yielded significantly inferior long-term outcome as compared to TCZ-based therapy in the COVID-19-associated group (P = 0.003). We report that a TCZ followed by consolidation therapy with a Janus kinase/signal transducer and activator of transcription (JAK/STAT) inhibitor given to 4 out of 8 critically ill COVID-19 patients resulted in their complete recovery. Non-selective JAK/STAT inhibitors influencing the action of several cytokines exhibit a broader effect than TCZ alone in calming down sCRS. Serum levels of cytokines and chemokines show similar changes in allogeneic-HSCT- and COVID-19-associated sCRS with marked elevation of interleukin-6 (IL-6), regulated upon activation normal T-cell expressed and secreted (RANTES), monocyte chemoattractant protein-1 (MCP-1) and interferon γ-induced protein 10 kDa (IP-10) levels. In addition, levels of IL-5, IL-10, IL-15 were also elevated in allogeneic-HSCT-associated sCRS. Our multi-cytokine expression data indicate that the pathophysiology of allogeneic-HSCT and COVID-19-associated sCRS are similar therefore the same clinical grading system and TCZ-based treatment approaches can be applied. TCZ with JAK/STAT inhibitor consolidation therapy might be highly effective in COVID-19 sCRS patients.

Pathology updates and diagnostic approaches to hemophagocytic lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a complex, often under-recognized hyperinflammatory immune dysregulation syndrome arising in a diverse range of clinical scenarios and conditions. The accurate and timely diagnosis of HLH is crucial for patient survival, and usually requires a high level of clinical suspicion. The histologic corollary to clinical HLH - hemophagocytosis - is neither necessary nor sufficient for the diagnosis of HLH, as it may be seen in a variety of reactive conditions and may be absent in true HLH. Nevertheless, the finding of hemophagocytosis in specific clinical situations should prompt consideration of HLH and further testing to exclude the condition. While traditionally described in bone marrow, identification of hemophagocytosis in other tissues, including lymphoid, splenic, liver, or neural tissue, can be an important asset to the overall recognition of HLH. In this review we discuss the underlying pathophysiology and etiologies of HLH, morphologic aspects of hemophagocytosis and its associated histologic findings in different tissues, and give a brief overview of diagnostic criteria and clinical evaluation.

Assessment of the HScore as a predictor of disease outcome in patients with COVID-19

Severe coronavirus disease 2019 (COVID-19) accompanies hypercytokinemia, similar to secondary hemophagocytic lymphohistiocytosis (sHLH). We aimed to find if HScore could predict disease severity in COVID-19. HScore was calculated in hospitalized children and adult patients with a proven diagnosis of COVID-19. The need for intensive care unit (ICU), hospital length of stay (LOS), and in-hospital mortality were recorded. The median HScore was 43.0 (IQR 0.0–63.0), which was higher in those who needed ICU care (59.7, 95% CI 46.4–72.7) compared to those admitted to non-ICU medical wards (38.8, 95% CI 32.2–45.4; P = 0.003). It was also significantly higher in patients who died of COVID-19 (105.1, 95% CI 53.7–156.5) than individuals who survived (41.5, 95% CI 35.8–47.1; P = 0.005). Multivariable logistic regression analysis revealed that higher HScore was associated with a higher risk of ICU admission (adjusted OR = 4.93, 95% CI 1.5–16.17, P = 0.008). The risk of death increased by 20% for every ten units increase in HScore (adjusted OR 1.02, 95% CI 1.00–1.04, P = 0.009). Time to discharge was statistically longer in high HScore levels than low levels (HR = 0.41, 95% CI 0.24–0.69). HScore is much lower in patients with severe COVID-19 than sHLH. Higher HScore is associated with more ICU admission, more extended hospitalization, and a higher mortality rate. A modified HScore with a new cut-off seems more practical in predicting disease severity in patients with severe COVID-19.

Models for SARS-CoV-2 associated thrombocytopenia associated with hemophagocytic histiocytes

A subset of COVID-19 patients is experiencing secondary immune thrombocytopenia, also called immune thrombocytopenic purpura (ITP) or secondary hemophagocytic lymphohistiocytosis (HLH). The pathogenesis of SARS-CoV-2 associated thrombocytopenia is unknown. Very rare cases of vaccine induced prothrombotic immune thrombocytopenia (VIPIT) are occurring associated with COVID-19 vaccines. COVID-19 VIPIT is associated with autoantibodies targeting platelet factor 4 (PF4) for COVID-19 adenovirus vaccines. Herein, four models for hemophagocytic histocytes contributions to the etiology of thrombocytopenia associated with SARS-CoV-2 are proposed. One of the models proposes potential involvement of hemophagocytic histocytes targeting platelets bound by autoantibodies consistent with observed PF4 autoantibodies in COVID-19 VIPIT.

Case Report: Successful Treatment of Five Critically Ill Coronavirus Disease 2019 Patients Using Combination Therapy With Etoposide and Corticosteroids

Acute respiratory distress syndrome (ARDS) is the leading cause of mortality in hospitalized patients with coronavirus disease 2019 (COVID-19) because of limited effective therapies. During infection, the accumulation and activation of macrophages and monocytes in the lungs induce inflammatory mediators and contribute to tissue injury, leading to ARDS. However, therapeutic strategies that directly target activated macrophage and monocytes have not been reported. Combination treatment with etoposide (a cytotoxic agent) and a corticosteroid has been widely used for treating hemophagocytic lymphohistiocytosis characterized by the systemic activation of macrophages with overwhelming inflammation. Herein, we present five cases of COVID-19-associated ARDS treated with etoposide and corticosteroids. Three of the five patients were over 65 years of age and had various underlying diseases, including multiple myeloma. Four patients required invasive mechanical ventilation (MV), and one patient refused to be placed on MV due to underlying diseases. All patients were pre-treated with antiviral and/or other anti-inflammatory agents, but their condition deteriorated and hyperinflammation was noted. All five patients responded well to treatment and had an immediate response, as reflected by improvement in their respiratory condition and inflammatory marker levels and rapid resolution of fever after etoposide administration; however, some patients required a second dose of etoposide and longer course of steroids. All patients recovered, and there were no severe adverse events related to the drugs. Following successful treatment in these five patients, we plan to conduct a clinical trial to evaluate the efficacy and safety of combination therapy with etoposide and corticosteroid for treating COVID-19 patients in Japan.

Secondary Hemophagocytic Lymphohistiocytosis in Post-COVID-19 Patients: A Report of Two Cases

Hemophagocytic lymphohistiocytosis (HLH) is a disease that can affect both children and adults. HLH can be categorized as primary or secondary. Secondary HLH (sHLH) may be secondary to various viral infections. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus infection is a pandemic with multi-system involvement. HLH in COVID-19 positive patients is a recognized entity. However, in post-COVID-19 patients who have recovered and are negative by serological tests and reverse transcription-polymerase chain reaction test may present with sHLH due to dysregulation of the immune system. We highlight this unusual finding of post-COVID-19 sHLH in two cases, who were diagnosed by the new revised H-score.

Evaluation of Bone Marrow Findings of COVID-19 by Minimally Invasive Autopsies: A Single Tertiary Care Centre Experience from India

The 2019 novel coronavirus (2019-nCoV) originated in Wuhan City of China. In India, first confirmed case of coronavirus disease (COVID-19) was reported on January 30, 2020 and India is presently hit by second wave of COVID-19. The aim of the present study was to evaluate bone marrow findings of COVID-19 by minimally invasive autopsies to aid in understanding pathophysiology of the disease. This prospective study was conducted at tertiary care centre of Western Rajasthan. After obtaining approval from Institute’s ethics committee and consent from next of kins, minimally invasive autopsies were conducted in 37 COVID-19 deceased patients within an hour after the death. The tissue specimens were processed with standard biosafety measures. Electronic medical records were reviewed retrospectively and patients’ clinical details and results of laboratory investigations were noted. In this prospective study, bone marrow biopsies were collected from 37 COVID-19 minimally invasive autopsies. Mean age of these cases was 61.8 years and male: female ratio was 2.36. Comorbidities were observed in 25 (67.5%) of all cases. Histopathological analysis revealed hypercellular, normocellular and hypocellular marrow in 5, 25 and 5 cases respectively (two biopsies were inadequate). There was marked interstitial prominence of histiocytes in 24 (68.5%) cases. Out of these, evidence of haemophagocytosis was observed in 14 (40%) cases, marked increase of haemosiderin laden macrophages in 20 (57.1%) cases. There was prominence of plasma cells in 28 (80%) cases. The present study attempted to fill the gap of dearth of literature from our country in COVID-19 autopsy studies by highlighting bone marrow findings. The data support the evidence of development of secondary haemophagocytic lymphocytosis in COVID-19 cases.

High Prevalence of Pre-Existing Liver Abnormalities Identified Via Autopsies in COVID-19: Identification of a New Silent Risk Factor?

A high prevalence of hepatic pathology (in 17 of 19 cases) was reported in post-mortem (PM) examinations of COVID-19 patients, undertaken between March 2020 and February 2021 by a single autopsy pathologist in two English Coronial jurisdictions. The patients in our cohort demonstrated high levels of recognised COVID-19 risk factors, including hypertension (8/16, 50%), type 2 diabetes mellitus (8/16, 50%) and evidence of arteriopathy 6/16 (38%). Hepatic abnormalities included steatosis (12/19; 63%), moderate to severe venous congestion (5/19; 26%) and cirrhosis (4/19; 21%). A subsequent literature review indicated a significantly increased prevalence of steatosis (49%), venous congestion (34%) and cirrhosis (9.3%) in COVID-19 PM cases, compared with a pre-pandemic PM cohort (33%, 16%, and 2.6%, respectively), likely reflecting an increased mortality risk in SARS-CoV-2 infection for patients with pre-existing liver disease. To corroborate this observation, we retrospectively analysed the admission liver function test (LFT) results of 276 consecutive, anonymised COVID-19 hospital patients in our centre, for whom outcome data were available. Of these patients, 236 (85.5%) had significantly reduced albumin levels at the time of admission to hospital, which was likely indicative of pre-existing chronic liver or renal disease. There was a strong correlation between patient outcome (length of hospital admission or death) and abnormal albumin at the time of hospital admission (p = 0.000012). We discuss potential mechanisms by which our observations of hepatic dysfunction are linked to a risk of COVID-19 mortality, speculating on the importance of recently identified anti-interferon antibodies.

Association of HScore Parameters with Severe COVID-19: A Systematic Review and Meta-Analysis

BACKGROUND

Several reports have associated the severe Coronavirus disease-2019 (sCOVID-19) with secondary-hemophagocytic lymphohistiocytosis (sHLH) and proposed utilizing the hemophagocytic syndrome diagnostic score (HScore) for sCOVID-19 patients. We conducted a systematic review and meta-analysis to find the possible association of HScore parameters with severity in COVID-19 patients.

METHODS

A systematic search was performed in Medline via PubMed, EMBASE, and Cochrane databases using all HScore and COVID-19 keywords. The studies were all from 2020, and the study language was limited to English. The records were screened based on inclusion/exclusion criteria. Random/fixed-effect models were employed for meta-analysis, based on the I2 index of parameters. The pooled mean differences were estimated for continuous parameters. The pooled odds-ratio was estimated for fever. The level of significance was set at 0.05.

RESULTS

Eighteen studies (comprising 2459 patients) out of 26151 screened studies were included in this meta-analysis. The results showed that the level of leukocyte, neutrophil, aspartate transaminase (AST), ferritin, and fibrinogen were significantly higher in sCOVID-19 patients than in non-severe ones. Significant lower levels of lymphocyte, platelet, and hemoglobin were also found in sCOVID-19 patients than non-severe patients. Fever was nearly associated with two times increased odds of sCOVID-19 (P=0.051).

CONCLUSION

Lymphopenia, thrombocytopenia, hypohemoglobinemia, hyperferritinemia, high levels of AST, and fever are common features of both sCOVID-19 and HLH. However, the leukocytosis, neutrophilia, and hyperfibrinogenemia found in sCOVID-19 are in contrast with HScore. Conclusively, HScore parameters could be risk factors for sCOVID-19. However, some parameters' roles are contradictory, suggesting the need for further investigation and a new way of HScore interpretation in sCOVID-19 patients.A preprint of this study was published at https://www.researchsquare.com/article/rs-54490/v2.

Translational deep phenotyping of deaths related to the COVID-19 pandemic: protocol for a prospective observational autopsy study

INTRODUCTION

The COVID-19 pandemic is an international emergency with an extreme socioeconomic impact and a high mortality and disease burden. The COVID-19 outbreak is neither fully understood nor fully pictured. Autopsy studies can help understand the pathogenesis of COVID-19 and has already resulted in better treatment of patients. Structured and systematic autopsy of COVID-19-related deaths will enhance the mapping of pathophysiological pathways, not possible in the living. Furthermore, it provides an opportunity to envision factors translationally for the purpose of disease prevention in this and future pandemics. This is the protocol for an autopsy study that offers an umbrella for deep and diverse investigations of COVID-19-related deaths, including a systematic investigation of 'long' COVID-19 by means of extensive and systematic tissue sampling.

METHODS AND ANALYSIS

A COVID-19-specific autopsy algorithm has been created to cover all cases undergoing clinical or forensic autopsy in Denmark. The algorithm describes advanced tissue sampling and a translational analytical follow-up for deep phenotyping. The translational approach covers registry data, postmortem imaging, gross autopsy findings, microscopic organ changes, postmortem toxicology, postmortem biochemical investigation, microbiological profiling and immunological status at the time of death, and future research projects covering genetics and epigenetics on an organ level.

ETHICS AND DISSEMINATION

This study has been approved by the Regional Ethics Committee of the Region of Greater Copenhagen (No: H-20078436) and the Danish Data Protection Agency (No: 2002-54-1080). Next of kin gave informed consent to research. The study results will be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

This study is purely observational and, as such, does not meet the criteria of the International Committee of Medical Journal Editors for clinical trials; thus, there is no need for registration in a database of research trials, such as clinical trials. To facilitate cooperation in research, provide transparency on case recruitment for publications to come and to avoid unnecessary duplicate work, we nevertheless wish to publish our protocol.

Cytokine Storms in the Course of COVID-19 and Haemophagocytic Lymphohistiocytosis in Pregnant and Postpartum Women

The term 'cytokine storm' (CS) applies to a pathological autoimmune reaction when the interactions that lead to cytokine production are destabilised and may even lead to death. CS may be induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In this study, we present our analysis of certain pathological processes that induce a CS in pregnant and postpartum women. We draw our attention to the similarities between the severe course of Coronavirus Disease 2019 (COVID-19) and haemophagocytic lymphohistiocytosis (HLH). It is noteworthy that many of the criteria used to diagnose HLH are described as COVID-19 mortality predictors. Cytokine storms are considered to be an important cause of death in patients with the severe course of SARS-CoV-2 infection. Due to the fact that pregnant women are in an immunosuppressive state, viral pulmonary infections are more perilous for them-possible risks include miscarriage, intrauterine growth restriction or birth before the term; sometimes ventilation support is needed. HLH should be considered in pregnant and puerperal women suffering from moderately severe to severe COVID-19 and presenting with: fever unresponsive to antibiotic therapy, cytopenia, hepatitis and hyperferritinaemia. The HLH disorder is rare and difficult to diagnose; however, its early detection could reduce patient mortality.

Viral Load and Patterns of SARS-CoV-2 Dissemination to the Lungs, Mediastinal Lymph Nodes, and Spleen of Patients with COVID-19 Associated Lymphopenia

Lymphopenia is a frequent hematological manifestation, associated with a severe course of COVID-19, with an insufficiently understood pathogenesis. We present molecular genetic immunohistochemical, and electron microscopic data on SARS-CoV-2 dissemination and viral load (VL) in lungs, mediastinum lymph nodes, and the spleen of 36 patients who died from COVID-19. Lymphopenia <1 × 109/L was observed in 23 of 36 (63.8%) patients. In 12 of 36 cases (33%) SARS-CoV-2 was found in lung tissues only with a median VL of 239 copies (range 18-1952) SARS-CoV-2 cDNA per 100 copies of ABL1. Histomorphological changes corresponding to bronchopneumonia and the proliferative phase of DAD were observed in these cases. SARS-CoV-2 dissemination into the lungs, lymph nodes, and spleen was detected in 23 of 36 patients (58.4%) and was associated with the exudative phase of DAD in most of these cases. The median VL in the lungs was 12,116 copies (range 810-250281), lymph nodes-832 copies (range 96-11586), and spleen-71.5 copies (range 0-2899). SARS-CoV-2 in all cases belonged to the 19A strain. A immunohistochemical study revealed SARS-CoV-2 proteins in pneumocytes, alveolar macrophages, and bronchiolar epithelial cells in lung tissue, sinus histiocytes of lymph nodes, as well as cells of the Billroth pulp cords and spleen capsule. SARS-CoV-2 particles were detected by transmission electron microscopy in the cytoplasm of the endothelial cell, macrophages, and lymphocytes. The infection of lymphocytes with SARS-CoV-2 that we discovered for the first time may indicate a possible link between lymphopenia and SARS-CoV-2-mediated cytotoxic effect.

Problems of Pathogenesis and Pathogenetic Therapy of COVID-19 from the Perspective of the General Theory of Pathological Systems (General Pathological Processes)

The COVID-19 pandemic examines not only the state of actual health care but also the state of fundamental medicine in various countries. Pro-inflammatory processes extend far beyond the classical concepts of inflammation. They manifest themselves in a variety of ways, beginning with extreme physiology, then allostasis at low-grade inflammation, and finally the shockogenic phenomenon of "inflammatory systemic microcirculation". The pathogenetic core of critical situations, including COVID-19, is this phenomenon. Microcirculatory abnormalities, on the other hand, lie at the heart of a specific type of general pathological process known as systemic inflammation (SI). Systemic inflammatory response, cytokine release, cytokine storm, and thrombo-inflammatory syndrome are all terms that refer to different aspects of SI. As a result, the metabolic syndrome model does not adequately reflect the pathophysiology of persistent low-grade systemic inflammation (ChSLGI). Diseases associated with ChSLGI, on the other hand, are risk factors for a severe COVID-19 course. The review examines the role of hypoxia, metabolic dysfunction, scavenger receptors, and pattern-recognition receptors, as well as the processes of the hemophagocytic syndrome, in the systemic alteration and development of SI in COVID-19.

Distinctive pseudopalisaded histiocytic hyperplasia characterizes the transition of exudative to proliferative phase of diffuse alveolar damage in patients dying of COVID-19

Severe COVID-19 results in a glucocorticoid responsive form of acute respiratory distress (ARDS)/diffuse alveolar damage (DAD). Herein we compare the immunopathology of lung tissue procured at autopsy in patients dying of SARS-CoV-2 with those dying of DAD prior to the COVID-19 pandemic. Autopsy gross and microscopic features stratified by duration of illness in twelve patients who tested positive for SARS-CoV-2 viral RNA, as well as seven patients dying of DAD prior to the COVID-19 pandemic were evaluated with multiplex (5-plex: CD4, CD8, CD68, CD20, AE1/AE3) and SARS-CoV immunohistochemistry to characterize the immunopathologic stages of DAD. We observed a distinctive pseudopalisaded histiocytic hyperplasia interposed between the exudative and proliferative phase of COVID-19 associated DAD, which was most pronounced at the fourth week from symptom onset. Pulmonary macrothrombi were seen predominantly in cases with pseudopalisaded histiocytic hyperplasia and/or proliferative phase DAD. Neither pseudopalisaded histiocytic hyperplasia nor pulmonary macrothrombi was seen in non-COVID-19 DAD cases, whereas microthrombi were common in DAD regardless of etiology. The inflammatory pattern of pseudopalisaded histiocytic hyperplasia may represent the distinctive immunopathology associated with the dexamethasone responsive form of DAD seen in severe COVID-19.

Myeloid phenotypes in severe COVID-19 predict secondary infection and mortality: a pilot study

BACKGROUND

De-regulated host response to severe coronavirus disease 2019 (COVID-19), directly referring to the concept of sepsis-associated immunological dysregulation, seems to be a strong signature of severe COVID-19. Myeloid cells phenotyping is well recognized to diagnose critical illness-induced immunodepression in sepsis and has not been well characterized in COVID-19. The aim of this study is to review phenotypic characteristics of myeloid cells and evaluate their relations with the occurrence of secondary infection and mortality in patients with COVID-19 admitted in an intensive care unit.

METHODS

Retrospective analysis of the circulating myeloid cells phenotypes of adult COVID-19 critically ill patients. Phenotyping circulating immune cells was performed by flow cytometry daily for routine analysis and twice weekly for lymphocytes and monocytes subpopulations analysis, as well as monocyte human leukocyte antigen (mHLA)-DR expression.

RESULTS

Out of the 29 critically ill adult patients with severe COVID-19 analyzed, 12 (41.4%) developed secondary infection and six patients died during their stay. Monocyte HLA-DR kinetics was significantly different between patients developing secondary infection and those without, respectively, at day 5-7 and 8-10 following admission. The monocytes myeloid-derived suppressor cells to total monocytes ratio was associated with 28- and 60-day mortality. Those myeloid characteristics suggest three phenotypes: hyperactivated monocyte/macrophage is significantly associated with mortality, whereas persistent immunodepression is associated with secondary infection occurrence compared to transient immunodepression.

CONCLUSIONS

Myeloid phenotypes of critically ill COVID-19 patients may be associated with development of secondary infection, 28- and 60-day mortality.

Invasive mould disease in fatal COVID-19: a systematic review of autopsies

Invasive mould disease (IMD) might affect up to a third of critically ill patients with COVID-19. COVID-19-associated pulmonary aspergillosis (CAPA) is typically diagnosed on the basis of a combination of non-specific clinical, radiographical, and mycological findings, but whether most cases represent invasive disease is unresolved. We systematically reviewed autopsy series of three or more decedents with COVID-19 for evidence of IMD. We searched PubMed, Web of Science, OVID (Embase), and medRxiv for studies in English or French published from Jan 1, 2019, to Sept 26, 2020. We identified 1070 references, of which 50 studies met the criteria. These studies described autopsies from 677 decedents, with individual-level data for 443 decedents. The median age was 70·0 years (IQR 57·0–79·0). Of decedents with individual-level data, 133 (30%) had diabetes, 97 (22%) had pre-existing lung disease, and 27 (6%) had immunocompromising conditions. Of 548 decedents with such data, 320 (58%) received invasive mechanical ventilation; among 140 decedents for whom this was known, ventilation was for a median of 9·0 days (IQR 5·0–20·0). Treatment included immunomodulation in 60 decedents and antifungals in 50 decedents. Autopsy-proven IMD occurred in 11 (2%) of 677 decedents, including eight CAPA, two unspecified IMD, and one disseminated mucormycosis. Among 320 decedents who received mechanical ventilation, six (2%) had IMD. We conclude that IMD, including CAPA, is an uncommon autopsy finding in COVID-19.

Plasma Von Willebrand Factor Levels Predict Survival in COVID-19 Patients Across the Entire Spectrum of Disease Severity

Background: Characterization of reticulo-endothelial activation in COVID-19 may guide treatment. Objectives: To assess reticulo-endothelial activation and its correlation with disease severity and death in patients across the entire spectrum of COVID-19 severity. Methods: Consecutive hospitalized COVID-19 patients were studied, with similar number of patients in each disease severity category. Baseline serum ferritin, sCD163 (macrophage activation markers) and plasma von Willebrand factor (VWF) antigen (endothelial activation marker) levels were studied. Clinical parameters and plasma D-dimer levels were also studied. The study parameters were correlated with COVID-19 severity and survival. Results: The 143 patients (104 males [80%], age 54 [42 – 65] years, median [inter-quartile range]) presented 4 (3—7) days after symptom onset. Thirty-four patients had mild disease, 36 had moderate disease, 36 had severe disease and 37 had critical disease at baseline. With increasing COVID-19 severity, ferritin, sCD163, VWF and D-dimer levels significantly increased at baseline, however, 139 patients had normal sCD163 levels. Of the reticulo-endothelial markers, VWF level independently correlated with COVID-19 severity and with survival. VWF level > 332.6 units/dl correlated with COVID-19 severity (odds ratio [OR]: 2.77 [95% confidence interval (C.I): 1.1 – 6.99], p value: 0.031) and in-hospital death (OR [95% CI]: 29.28 [5.2 – 165], p value < 0.001). Conclusions: Reticulo-endothelial activation markers increased incrementally with worsening COVID-19 severity. Baseline endothelial activation marker (VWF), and not macrophage activation markers, independently correlated with COVID-19 severity and death.