Hematologic findings associated with thrombocytopenia during the acute phase of exanthem subitum confirmed by primary human herpesvirus-6 infection

Roseola Infantum: An Updated Review

BACKGROUND

Roseola infantum is a common viral disease that occurs during childhood worldwide.

OBJECTIVE

The purpose of this article is to familiarize pediatricians with the clinical manifestations, evaluation, diagnosis, and management of roseola infantum.

METHODS

A search was conducted in April, 2022, in PubMed Clinical Queries using the key terms "roseola infantum" OR "exanthem subitum" OR "sixth disease". The search strategy included all clinical trials, observational studies, and reviews published within the past 10 years. Only papers published in the English literature were included in this review. The information retrieved from the above search was used in the compilation of the present article.

RESULTS

Roseola infantum is a viral illness characterized by high fever that lasts 3 to 4 days, followed by the sudden appearance of rash at defervescence. The disease occurs most frequently in children between 6 months and 2 years of age. Human herpesvirus-6 (HHV-6) is the major cause of roseola infantum, followed by HHV-7. Transmission of the infection most likely results from the asymptomatic shedding of the virus in the saliva of the caregivers or other close contacts. Characteristically, the rash is discrete, rose-pink in color, circular or elliptical, macular or maculopapular, measuring 2 to 3 mm in diameter. The eruption is first seen on the trunk. It then spreads to the neck and proximal extremities. Typically, the rash blanches on pressure and subsides in 2 to 4 days without sequelae. Most children look well otherwise and appear to be happy, active, alert, and playful. The diagnosis is mainly clinical. Febrile seizures occur in 10 to 15 % of children with roseola infantum during the febrile period. In general, serious complications are rare and occur more often in individuals who are immunocompromised. There is no specific treatment. An antipyretic may be used to reduce fever and discomfort.

CONCLUSION

Roseola infantum is generally a benign and self-limited disease. Failure to recognize this condition may result in undue parental fear, unnecessary investigations, delay in treatment for conditions that mimic roseola infantum and complications from roseola infantum, unnecessary treatment of roseola infantum per se, and misuse of healthcare expenditure.

Roseola Infantum During the COVID-19 Pandemic

INTRODUCTION

Roseola infantum is always considered to be among the differential diagnosis of young patients with fever and leukopenia whom to be strictly isolated with the preliminary diagnosis of COVID-19 until otherwise proven during the pandemic.

RESULTS

Human herpes virus-6 (HHV-6) polymerase chain reaction (PCR) blood test was performed in 4 of 7 patients with a clinical diagnosis of roseola infantum and all found to be HHV-6 PCR positive. The most striking laboratory finding in all patients was leukopenia. HHV-6 PCR tests were found to be positive. Severe acute respiratory syndrome coronavirus-2 testing were found to be negative in all patients.

CONCLUSION

During the peak of the pandemic, children continued to present with fever because of viral infections other than COVID-19.

Post-marketing surveillance of adverse events following measles, mumps, rubella and varicella (MMRV) vaccine: retrospecive study in apulia region (ITALY), 2009-2017

Since 2006, some Italian Regions introduced the active offer of measles, mumps, rubella, and varicella (MMRV) vaccine for all newborns during the second years of life. In 2011, Italian Drug Authority (AIFA) recommended the discontinuation of the MMRV use for an increased risk of febrile seizures following vaccination; furthermore, some Regions (such as Apulia, that introduced MMRV offer in 2009) chose to continue the use of MMRV and Ministry of Health recommended to guarantee supplemental monitoring of safety of the vaccine. In Italy, the surveillance of Adverse Events following immunization (AEFIs) is currently carried out by AIFA and Regional Health Authorities; this paper aims to summarize the results of MMRV-vaccine surveillance of AEFIs program carried out in Apulia. From the AIFA database, we selected MMRV AEFIs that occurred in Apulia (about 4,000,000 inhabitants) from 2009 to 2017. For serious AEFIs, we applied the WHO causality assessment algorithm, using for cases hospitalized information from individual medical records. In the 8 years of observation, 155 MMRV-AEFIs (reporting rate: 37.9×100,000 doses) occurred of which 26 were classified as serious (6.3×100,000 doses) and 22 led to hospitalization. Performing causality assessment, for 10 the classification was "consistent causal association to immunization" (reporting rate: 2.4×100000 doses), for 2 indeterminate, for 13 "inconsistent causal association to immunization" and for 1 not-classifiable. No case of febrile seizure resulted consistent to vaccination. All consistent serious AEFIs were completely resolved at subsequent follow-up.

HHV-6-Associated Neurological Disease in Children: Epidemiologic, Clinical, Diagnostic, and Treatment Considerations

Human herpesviruses 6A and 6B, often referred to collectively as human herpesvirus 6, are a pair of beta-herpesviruses known to cause a variety of clinical syndromes in both immunocompetent and immunocompromised individuals. Most humans are infected with human herpesvirus 6B, and many with human herpesvirus 6A. Primary infection typically occurs in early childhood, although large-scale reviews on the topic are limited. Herein, the authors explore the clinical manifestations of human herpesvirus 6-associated disease in both immunocompetent and immunocompromised pediatric patients, the risk factors for development of human herpesvirus 6-associated neurological disease, the risk of autoimmunity associated with development of active or latent infection, the relevance of human herpesvirus 6-specific diagnostic tests, and the medications used to treat human herpesvirus 6. The goal of this review is to improve the current understanding of human herpesvirus 6 in pediatric populations and to examine the most effective diagnostic and therapeutic interventions in this disease state.

Leukocytoclastic Vasculitis Associated with HHV6-A/ciHHV6-A and HHV6-B Coinfection in an Immunocompetent Woman

Conclusion:

In light of the transcriptional activity documented in our case, further examination of a possible role for HHV-6 in the etiology of LCV is warranted.

Lymphoproliferative Syndromes Associated with Human Herpesvirus-6A and Human Herpesvirus-6B

Human herpesvirus 6A and 6B (HHV-6A and HHV-6B) have been noted since their discovery for their T-lymphotropism. Although it has proven difficult to determine the extent to which HHV-6A and HHV-6B are involved in the pathogenesis of many diseases, evidence suggests that primary infection and reactivation of both viruses may induce or contribute to the progression of several lymphoproliferative disorders, ranging from benign to malignant and including infectious mononucleosis-like illness, drug induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS), and nodular sclerosis Hodgkin's lymphoma. Herein, we discuss the conditions associated with the lymphoproliferative capacity of HHV-6, as well as the potential mechanisms behind them. Continued exploration on this topic may add to our understanding of the interactions between HHV-6 and the immune system and may open the doors to more accurate diagnosis and treatment of certain lymphoproliferative disorders.

Human Herpesvirus 6 Infection Presenting as an Acute Febrile Illness Associated with Thrombocytopenia and Leukopenia

We present an infant with acute fever, thrombocytopenia, and leukopenia, coming from an endemic region for tick-borne encephalitis, human granulocytic anaplasmosis, and hantavirus infection. The primary human herpesvirus 6 infection was diagnosed by seroconversion of specific IgM and IgG and by identification of viral DNA in the acute patient's serum. The patient did not show skin rash suggestive of exanthema subitum during the course of illness.

Pathogenesis of Severe Neutropenia in Patients With Primary Human Herpesvirus 6B Infection

BACKGROUND

Although myelosuppression caused by human herpesvirus 6B (HHV-6B) reactivation in transplant recipients has been extensively investigated, the pathophysiological mechanisms of severe neutropenia in primary HHV-6B infection remain unclear.

PROCEDURE

Fifty-four patients with primary HHV-6B infection were evaluated. Hematological examinations and blood sampling were conducted on days 1-4 (pre) and 5-10 (post) after the onset of illness. Severe neutropenia was defined as a neutrophil count less than 500 cells/μL. Patient characteristics, clinical data, and cytokines and chemokines levels were compared between the patients with (n = 16) and without (n = 38) severe neutropenia.

RESULTS

Severe neutropenia was detected in samples that were collected between days 5 and 10 after illness. Significantly lower platelet counts (pre, P = 0.048; post, P = 0.032) and regulated on activation, normal T cell expressed and secreted levels (post, P = 0.007) were detected in the patients with neutropenia. Aspartate aminotransferase levels (P = 0.008), and interferon γ-inducible protein-10 (P < 0.0001), monocyte chemoattractant protein-1 (P = 0.005), and monokine induced by interferon γ (P = 0.011) levels were significantly higher in post samples collected from the patients with neutropenia. No differences were observed in any patient characteristics and serum cytokines levels. No bacterial infections were detected during the observation period.

CONCLUSIONS

Chemokines may play an important role in the pathogenesis of severe neutropenia in patients with primary HHV-6B infection.

The epidemiology, clinical course and outcome of febrile cytopenia in children

AIM

Transient infectious neutropenia of mild-to-moderate severity is common and resolves spontaneously within weeks. This was the first prospective study of the whole spectrum of febrile cytopenia in noncancer patients followed-up for 2 years. It aimed to assess its aetiology, duration and outcome.

METHODS

We evaluated 116 children with febrile cytopenia aged 4 ± 3.8 years, admitted to a paediatric ward over 2 years, using inflammatory markers, cultures and serological tests.

RESULTS

An infectious agent was identified in 74 (63.8%) cases: 44.8% viral, 11.2% bacterial and 7.8% parasitic. One cell line was affected in 26.7% of patients and ≥2 cell lines in 73.3%. Cytopenia was transient in 82.75% of cases and chronic in 17.24%. The transient cytopenia subgroups - exhibited differences in severity (mild in bacterial cases and moderate in viral and parasitic cases, p = 0.018) and the number of affected cell lines, (predominantly two in viral and bacterial cases and pancytopenia in parasitic cases, p = 0.001). Chronic patients had severe cytopenia (p = 0.004) with ≥2 cell lines affected, while transient patients had mild-to-moderate cytopenia, with 1-3 cell lines affected.

CONCLUSION

Childhood febrile cytopenia is usually transient, of mild-to-moderate severity, and resolves spontaneously, but patients with severe cytopenia affecting ≥2 cell lines need further evaluation and follow-up.

Epstein-Barr virus: dermatologic associations and implications: part I. Mucocutaneous manifestations of Epstein-Barr virus and nonmalignant disorders

Epstein-Barr virus (EBV) is a ubiquitous virus that has been implicated in a wide range of human diseases, many of which have mucocutaneous manifestations. As a member of the herpesviridae family, EBV causes lifelong infection by establishing latency in B lymphocytes. An intact immune response is critical in preventing progression of EBV disease, and the clinical manifestations of infection are dependent on the intricate relationship between virus and host immune system. This review provides a comprehensive overview of the epidemiology, pathophysiology, and diagnostic testing in EBV infection. In part I of this continuing medical education article, the mucocutaneous manifestations of EBV infection are reviewed with an emphasis on pathophysiology and management.

Roseola infantum and its causal human herpesviruses

Roseola infantum, also known as exanthem subitum or sixth disease, is a generally benign febrile exanthem of infancy. It has a characteristic clinical course of high fever followed by the appearance of an exanthem upon defervescence. Febrile seizures are a frequent complication. Roseola is caused by infection with human herpesviruses 6 or 7 (HHV-6/7), which are acquired at a young age. Diagnosis is made by serology or by virus detection in body fluids and tissues. Treatment of roseola is supportive; recovery is usually complete with no significant sequelae. However, HHV-6/7 can reactivate in immunocompetent as well as immunocompromised individuals with severe systemic consequence.

Human herpesvirus 6 infection and transient acquired myelodysplasia in children

BACKGROUND

To demonstrate that primary human herpesvirus 6 (HHV-6) infection in childhood can cause hematopoietic dysplasia that mimics a myelodysplastic syndrome (MDS) in severe cases.

PROCEDURE

Seven immunocompetent children, who presented at admission with concomitant cytopenias in blood and morphologic features of dysplasia in bone marrow, were evaluated. Diagnosis of acute HHV-6 infection was secondary made by detection of HHV-6 DNA in plasma, bone marrow, or cerebrospinal fluid and measurement of plasma antibody titers. Peripheral blood and bone marrow aspirate smears were examined at diagnosis and during follow-up. Morphologic recognition of myelodysplasia was made according to the recommendations of the Third MIC Cooperative Group.

RESULTS

Anemia was the most frequent cytopenia (five of seven cases). Bi- or tri-lineage dysplasia was observed in the marrow samples. Granulocytic and erythroid cells were always affected with dysgranulopoiesis and dyserythropoiesis scores equal to or higher than 3. Myelodysplasia was not due to a clonal disorder and disappeared gradually within 1 or 2 months.

CONCLUSIONS

Our results indicate that severe HHV-6 infection may induce reversible myelodysplastic changes. These findings contribute to elucidate the pathogenicity of HHV-6 and furthermore suggest that HHV-6 infection must also be considered as a cause of dysplasia in the differential diagnosis of MDS.

Update on human herpesvirus 6 biology, clinical features, and therapy

Human herpesvirus 6 (HHV-6) is a betaherpesvirus that is closely related to human cytomegalovirus. It was discovered in 1986, and HHV-6 literature has expanded considerably in the past 10 years. We here present an up-to-date and complete overview of the recent developments concerning HHV-6 biological features, clinical associations, and therapeutic approaches. HHV-6 gene expression regulation and gene products have been systematically characterized, and the multiple interactions between HHV-6 and the host immune system have been explored. Moreover, the discovery of the cellular receptor for HHV-6, CD46, has shed a new light on HHV-6 cell tropism. Furthermore, the in vitro interactions between HHV-6 and other viruses, particularly human immunodeficiency virus, and their relevance for the in vivo situation are discussed, as well as the transactivating capacities of several HHV-6 proteins. The insight into the clinical spectrum of HHV-6 is still evolving and, apart from being recognized as a major pathogen in transplant recipients (as exemplified by the rising number of prospective clinical studies), its role in central nervous system disease has become increasingly apparent. Finally, we present an overview of therapeutic options for HHV-6 therapy (including modes of action and resistance mechanisms).