Viral infection of megakaryocytes in varicella with purpura

Immune Thrombocytopenia (ITP) in a Pediatric Patient Positive for SARS-CoV-2

Immune thrombocytopenia (ITP) is a potential presentation of COVID-19. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral testing should be considered in these patients to allow for appropriate hospital triaging and isolation to limit community spread and health care worker infection during epidemics or pandemics. ITP is characterized by isolated thrombocytopenia. Approximately two-thirds of children with primary ITP have a history of a viral infection during the previous month.^1,2 Viruses commonly identified as triggers include cytomegalovirus, hepatitis C, herpes, varicella zoster, Epstein-Barr, influenza, and HIV.^3-7 In this case report, we describe the first documented case of a pediatric patient with ITP who tested positive for SARS-CoV-2. This case raises awareness of ITP as a possible pediatric presentation of coronavirus disease.

Correlation between cytokines and coagulation-related parameters in patients with coronavirus disease 2019 admitted to ICU

BACKGROUND

The novel SARS-CoV-2 caused a large number of infections and deaths worldwide. Thus, new ideas for an appropriated assessment of patients' condition and clinical treatment are of utmost importance. Therefore, in this study, the laboratory parameters of patients with coronavirus disease 2019 (COVID-19) were evaluated to identify the correlation between cytokine expression and other laboratory parameters.

METHODS

A retrospective and single-center study was performed in Wuhan, involving 83 severe or critical COVID-19 patients admitted to the intensive care unit (ICU). Laboratory parameters in ICU patients with laboratory-confirmed infection of SARS-CoV2 were collected. The association between parameters was assessed by Spearman's rank correlation.

RESULTS

Patients' median age was 66 years (IQR, 57-73), and 55 (66%) were men. Among the 83 patients, 61 (73%) had 1 or more coexisting medical condition. The median concentration of IL-2R, IL-6, IL8, IL10, and TNFα were above the normal range, without IL-1β. A significant negative correlation between IL-6 and platelet count was discovered (r² = -0.448, P < 0.001) as well as a significant correlation between IL-6 and other platelet parameters. Finally, a correlation between multiple cytokines and coagulation indicators was found, pro-inflammatory factors were found to be more associated to coagulation parameters, with the highest correlation between IL-6 and the International normalized ratio (INR) (r² = 0.444, P < 0.001).

CONCLUSIONS

Our results suggested that cytokines play an important role in the pathogenesis of COVID-19. In addition, IL-6 seems more relevant in the evaluation of the condition of COVID-19 patients.

Severe Immune Thrombocytopenia Complicated by Intracerebral Haemorrhage Associated with Coronavirus Infection: A Case Report and Literature Review

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder that causes isolated thrombocytopenia. Many viruses have been identified as triggering the autoimmune process, including HIV, MCV, EBV, parvovirus, rubella and measles. However, ITP in association with coronavirus infection has not previously been reported. We describe the case of a healthy man who presented with severe ITP complicated by intracranial haemorrhage following upper respiratory tract infection. An infection screen revealed coronavirus infection.

Correlation Between Abnormal Platelet Count and Respiratory Viral Infection in Patients From Cheonan, Korea

BACKGROUND

In this study, the effects of viral infections on platelet (PLT) count have been reported. This study examined the correlation between PLT count and respiratory virus (RV) infections.

METHODS

Patients who visited Dankook University Hospital between December 2006 and February 2014 with symptoms of suspected RV infection were recruited. Multiplex reverse transcriptase polymerase chain reactions identified the causative virus(es). PLT counts were analyzed with respect to virus, age and sex of the patient, and length of hospital stay.

RESULTS

Of the 8,147 patients, 62.8% were RV-positive, and 18.6% of RV-positive patients had abnormal PLT counts. There were no differences in the rates of abnormal PLT counts between single-infection and virus co-infection cases. In RV infection patients, the incidence of abnormal PLT count increased with age and varied depending on the RV infection type. Patients with abnormal PLT count stayed in hospital longer than those with normal PLT count.

CONCLUSIONS

The incidence of thrombocytopenia was higher among the elderly; in younger patients, thrombocytosis was more prevalent than thrombocytopenia. Respiratory tract infections caused by different viruses resulted in varied PLT count changes. Further systematic research of PLT count changes related to viral infections is required.

Virus-associated idiopathic thrombocytopenic purpura

Two-thirds of children with acute idiopathic thrombocytopenic purpura (ITP) have a history of an infectious illness a few days to a few weeks before the onset of thrombocytopenia. In a subset of affected children, identification of a specific virus can be made, such as varicella zoster virus, rubella, Epstein-Barr virus, influenza, or human immunodeficiency type 1 virus, indicating an etiological role for preceding viral infection in these children with ITP. While inhibition of thrombopoiesis has been established to play a role in thrombocytopenia associated with infection with some viruses, it does not appear to play a major role in the etiology of most typical ITP cases. Rather, enhanced clearance of platelets by the reticuloendothelial system is considered to be, at least in part, responsible for the thrombocytopenia which occurs during the viremic phase of acute virus infection or which develops days to weeks following the virus illness. Molecular mimicry between viral antigens and host proteins has been implicated in a number of autoimmune phenomena, and may be involved in the enhanced platelet clearance in virus-associated ITP.

Varicella-associated thrombocytopenia: autoantibodies against platelet surface glycoprotein V

Varicella zoster infection in children can be complicated by acute idiopathic thrombocytopenic purpura (ITP). To determine the etiologic mechanism of this thrombocytopenia, we studied three children with clinically diagnosed varicella infection. Immunoblot analysis of these patients' anti-platelet antibodies identified a unique band at 85 kD. Characterization of this protein revealed that it was platelet surface glycoprotein V (GPV) because it was not affected by a disulfide bond reduction but was cleaved by thrombin. Bernard-Soulier syndrome (BSS) platelets deficient in GPIb-IX and GPV did not react with the sera from our varicella-infected study patients. There was no apparent cross-reactivity between anti-varicella antibody and patients' anti-GPV Ig. We report here the first cases of GPV as the target antigen in autoimmune thrombocytopenia.

Herpes zoster-associated idiopathic thrombocytopenic purpura in a liver transplant recipient: a case report and overview

Idiopathic (autoimmune) thrombocytopenic purpura has been previously reported as a rare complication in children and in a few adults following chickenpox. We report a case of varicella zoster virus-associated idiopathic thrombocytopenic purpura in an adult liver transplant recipient following dermatomal zoster. Idiopathic thrombocytopenic purpura developed 3 days after the onset of herpes zoster in our patient, with a nadir platelet count of 3000/mm3. The patient was treated with intravenous gamma globulin with recovery of thrombocytopenia after 3 weeks. Transplant clinicians need to be aware that this serious and potentially life-threatening complication may occur with herpes zoster in transplant recipients.

Varicella zoster gastritis in a bone marrow transplant recipient

A case is reported of a patient who had previously undergone autologous bone marrow transplantation for recurrent Hodgkin's disease. The patient developed a generalised vesicular skin eruption. The clinical diagnosis was of disseminated shingles. Herpes viral particles were identified within the vesicular fluid by electron microscopy and using a specific monoclonal antibody to varicella zoster virus (VZV), positive immunofluorescence was detected in scrapings from the base of a vesicle. Gastroscopy and biopsy were performed because of severe abdominal pain and vomiting. The histological features were of non-specific active inflammation. Despite the histological absence of viral inclusions electron microscopy of the gastric biopsy revealed the presence of intranuclear herpes viral particles with a diameter of 90-100 nm. VZV specific DNA was detected by the polymerase chain reaction in the gastric biopsy extract. The patient was treated with acyclovir and made a full recovery.

Platelet antigens in varicella associated thrombocytopenia

Serum IgG or, predominantly, IgM antibody binding to electrophoretically separated normal platelet membrane protein antigens were detected by immunoblotting in five children with thrombocytopenia associated with varicella. Glycoproteins GPIb, GPIIb, GPIIIa, and other 25-260 kilodalton (kDa) proteins were identified as target antigens, suggesting a transient autoimmune mechanism causing the thrombocytopenia.

Megakaryocyte function and dysfunction

More than a hundred years have passed since platelets were recognized as cells and their haemostatic functions discovered. However, the process of platelet production is still not understood. The location, the mechanism and the regulation of thrombopoiesis remain elusive. Megakaryocytes are known to be the source of platelets. Investigations of megakaryocytes have revealed their normal functions and some of the abnormalities present in various diseases which affect platelets. In recent years, new techniques of cell isolation and tissue culture have been developed and have made possible advances in characterizing megakaryocyte precursors and differentiation. The primary function of megakaryocytes is to synthesize and assemble platelet components and organelles. Although debated for a long time, new data seems to indicate that the lung may be a central locus of platelet production. The new techniques for megakaryocyte investigations have barely begun to be of use in the study of abnormal platelet production in disease.

Association of herpes simplex virus with platelets of experimentally infected mice

In mice infected with herpes simplex virus (HSV) type 1 by the intracerebral route or with HSV type 2 by the vaginal route, virus was shown to be present in greater quantities in purified platelets than in leucocytes or other blood components. Results of the studies described suggest that platelets may play a major role in the hematogenous dissemination of HSV infection.

Mechanisms of thrombocytopenia in varicella

51Cr-labeled platelet and 125I-labeled fibrinogen kinetic studies in four thrombocytopenic children with varicella infection revealed marked platelet destruction (platelet survival times 0.1, 0.4, 1.0, and 2.4 days) and relatively normal fibrinogen disappearance. The platelet count was directly related to the platelet survival time. Marrow megakaryocyte mass was increased twofold to fourfold. IgG or IgM antiplatelet antibody was present on autologous platelets in the three patients tested. These data suggest that thrombocytopenia in some patients with varicella is the consequence of immune mediated platelet destruction.

Acute idiopathic thrombocytopenic purpura in children

Acute idiopathic thrombocytopenic purpura (ITP) characteristically follows a viral illness in preschool children. The exact role of viruses in the pathogenesis of this disorder remains uncertain, but the finding of markedly elevated levels of platelet-associated IgG serves to distinguish it from the chronic form of the disease and permits speculation on the mechanisms of platelet destruction. Although the spleen is important in both antibody production and platelet destruction, bone marrow synthesis of IgG has also been shown to be increased. The clinical course may be alarming, but mortality is low and prognosis excellent. Controversy has surrounded the role of steroids in the management of acute childhood ITP in retrospective studies. Controlled studies, however, indicate that thrombocytopenia is reversed sooner in treated patients. New assays for platelet-associated IgG offer new insights into this disorder and will allow delineation of acute and chronic disease at the time of diagnosis.