Drug-Induced Hypersensitivity Syndrome Followed by Subacute Thyroiditis

From Viral Infection to Autoimmune Reaction: Exploring the Link between Human Herpesvirus 6 and Autoimmune Diseases

The complexity of autoimmunity initiation has been the subject of many studies. Both genetic and environmental factors are essential in autoimmunity development. Among others, environmental factors include infectious agents. HHV-6 is a ubiquitous human pathogen with a high global prevalence. It has several properties suggestive of its contribution to autoimmunity development. HHV-6 has a broad cell tropism, the ability to establish latency with subsequent reactivation and persistence, and a range of immunomodulation capabilities. Studies have implicated HHV-6 in a plethora of autoimmune diseases-endocrine, neurological, connective tissue, and others-with some studies even proposing possible autoimmunity induction mechanisms. HHV-6 can be frequently found in autoimmunity-affected tissues and lesions; it has been found to infect autoimmune-pathology-relevant cells and influence immune responses and signaling. This review highlights some of the most well-known autoimmune conditions to which HHV-6 has been linked, like multiple sclerosis and autoimmune thyroiditis, and summarizes the data on HHV-6 involvement in autoimmunity development.

Immunopathogenic Insights on Preferential Human Herpesvirus-6 Reactivation in Drug Rash With Eosinophilia and Systemic Symptoms: A Scoping Review

INTRODUCTION

Human herpesvirus-6 (HHV-6) is a ubiquitous lymphotropic betaherpesvirus that can reactivate in drug rash with eosinophilia and systemic symptoms (DRESS). Despite recent publications advancing our understanding of HHV-6 in DRESS, the exact role of HHV-6 in disease pathogenesis remains unclear.

METHODS

A scoping review with the PubMed query "(HHV 6 AND (drug OR DRESS OR DIHS)) OR (HHV6 AND (drug OR DRESS OR DIHS))" was conducted in accordance with PRISMA guidelines. Articles containing original data on at least one DRESS patient with HHV-6 testing were included.

RESULTS

Our search returned a total of 373 publications, of which 89 met eligibility criteria. HHV-6 reactivation occurred in 63% of DRESS patients (n = 748), which was significantly more often than other herpesviruses. HHV-6 reactivation was associated with worse outcomes and greater severity in controlled studies. Case reports have demonstrated sometimes fatal HHV-6-related multi-organ involvement. Temporally, HHV-6 reactivation typically occurs 2 to 4 weeks after DRESS onset and has been linked to markers of immunologic signaling, such as OX40 (CD134), an HHV-6 entry receptor. Efficacy of antiviral or immunoglobulin treatment has only been demonstrated anecdotally, and steroid use may affect HHV-6 reactivation.

CONCLUSION

HHV-6 is implicated in DRESS more than in any other dermatologic condition. It is still unclear whether HHV-6 reactivation is cause or consequence of DRESS dysregulation. Similar pathogenic mechanisms precipitated by HHV-6 in other contexts may be relevant in DRESS. Future randomized controlled studies to assess effects of viral suppression on clinical outcomes is needed.

Late sequelae of drug reaction with eosinophilia and systemic symptoms (DRESS) cause thyroid dysfunction and thyroiditis: review of literature

Drug reaction with eosinophilia and systemic symptoms (DRESS) is one of the severe cutaneous adverse drug reactions (SCARs) with high mortality rate and variable long term sequelae, especially in thyroid dysfunction and thyroiditis. In this article, we review clinical course, culprit drugs, onset of diagnosis, and type of thyroid dysfunction in DRESS patients. There were a total of 51 cases including 12 children (aged less than 18 years old) and 39 adults from our review. The most common thyroid dysfunction was Hashimoto's thyroiditis (41/51=80.4%) including anti-thyroid antibody positive (29/51=56.9%), possible/compatible with Hashimoto's thyroiditis (12/51=23.5%) both in the children (n=12) and adult (n=39), Graves' disease/hyperthyroidism (7/51=13.7%) and non-specific hypothyroidism (3/51=5.9%), respectively. The most common culprit drugs and onset of thyroid dysfunction after DRESS diagnosis in children aged less than 18 years include antiepileptic drugs (phenytoin, phenobarbital, carbamazepine) (range 0-8 months, median 2 months) and sulfa groups (sulfasalazine, sulfamethoxazole, sulfonamide) (range 1-4 months, median 2 months). Data of prevalence, type, and clinical course of thyroid dysfunction from DRESS is important for clinicians to recognize for monitoring its sequelae and provide plans for treatment.

Co-Occurrence of Multiple Endocrine Abnormalities Induced by the DIHS/DRESS

BACKGROUND

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is a severe adverse reaction caused by specific drugs. However, little information is available about sequelae following DIHS/DRESS resolution from an endocrinologist's perspective. This study aimed to investigate the endocrine sequelae following DIHS/DRESS, from clinical feature to etiology.

METHODS

We retrospectively analyzed the patients diagnosed with DIHS/DRESS in Peking Union Medical College Hospital (PUMCH) during the period of 1 January 2012 to 31 December 2017, and those who developed endocrine disorders after DIHS/DRESS were further examined. We also reviewed the literature, from 1 January 2000 to 31 December 2017, on involvement of endocrine glands in DIHS/DRESS patients.

RESULTS

Three patients developed both autoimmune thyroid disease (AITD) and type 1 diabetes (T1DM)/fulminant type 1 diabetes (FT1DM) of the 45 patients. Seven cases involving more than two endocrine glands were reported in the literature. Our results indicated that DIHS/DRESS is a potential etiological factor of autoimmune polyendocrine syndrome (APS), especially APS III.

CONCLUSIONS

Patients require careful long-term follow-up after DIHS/DRESS. Involvement of endocrine glands, especially FT1DM, should always be monitored in patients with a history of DIHS/DRESS. This study indicated that DIHS/DRESS could lead to APS, especially APS III, providing novel insights into the etiological factors of APS.

Severe Delayed Drug Reactions: Role of Genetics and Viral Infections

Adverse drug reactions (ADRs) are a significant source of patient morbidity and mortality and represent a major burden to health care systems and drug development. Up to 50% of such reactions are preventable. Although many ADRs can be predicted based on the on-target pharmacologic activity, ADRs arising from drug interactions with off-target receptors are recognized. Off-target ADRs include the immune-mediated ADRs (IM-ADRs) and pharmacologic drug effects. In this review, we discuss what is known about the immunogenetics and pathogenesis of IM-ADRs and the hypothesized role of heterologous immunity in the development of IM-ADRs.