Drug-induced hypersensitivity syndrome due to cyanamide associated with multiple reactivation of human herpesviruses

Update on human herpesvirus 7 pathogenesis and clinical aspects as a roadmap for future research

Human herpesvirus 7 (HHV-7) is a common virus that is associated with various human diseases including febrile syndromes, dermatological lesions, neurological defects, and transplant complications. Still, HHV-7 remains one of the least studied members of all human betaherpesviruses. In addition, HHV-7-related research is mostly confined to case reports, while in vitro or in vivo studies unraveling basic virology, transmission mechanisms, and viral pathogenesis are sparse. Here, we discuss HHV-7-related literature linking clinical syndromes to the viral life cycle, epidemiology, and viral immunopathogenesis. Based on our review, we propose a hypothetical model of HHV-7 pathogenesis inside its host. Furthermore, we identify important knowledge gaps and recommendations for future research to better understand HHV-7 diseases and improve therapeutic interventions.

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms. Part I. Epidemiology, pathogenesis, clinicopathological features, and prognosis

Drug-induced hypersensitivity syndrome (DiHS), also known as drug reaction with eosinophilia and systemic symptoms (DRESS), is a severe cutaneous adverse reaction (SCAR) characterized by an exanthem, fever, and hematologic and visceral organ involvement. Anticonvulsants, antibiotics, and allopurinol are the most common triggers. The pathogenesis involves a complex interplay between drugs, viruses, and the immune system primarily mediated by T-cells. DiHS/DRESS typically presents with a morbilliform eruption 2-6 weeks after drug exposure, and is associated with significant morbidity, mortality, and risk of relapse. Long-term sequelae primarily relate to organ dysfunction and autoimmune diseases. Part I of this continuing medical education activity on DiHS/DRESS provides an update on epidemiology, novel insights into pathogenesis, and a description of clinicopathological features and prognosis.

Renal Manifestations of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome: A Systematic Review of 71 Cases

Unlike other adverse drug reactions, visceral organ involvement is a prominent feature of drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome and correlates with mortality. The aim of this study was to systematically review cases published in PubMed-indexed, peer-reviewed journals in which patients had renal injury during the episode of DRESS syndrome (DS). We found 71 cases, of which 67 were adults and 56% were males. Female sex was associated with higher mortality. Chronic kidney disease (CKD) was present in 14% of patients who developed acute kidney injury (AKI) during DS. In 21% of cases, the kidneys were the only visceral organ involved, while 54% of patients had both liver and kidney involvement. Eosinophilia was absent in 24% of patients. The most common classes of medication associated with renal injury in DS were antibiotics in 34%, xanthine oxidase inhibitors in 15%, and anticonvulsants in 11%. Among antibiotics, vancomycin was the most common culprit in 68% of patients. AKI was the most common renal manifestation reported in 96% of cases, while isolated proteinuria or hematuria was present in only 4% of cases. In cases with AKI, 88% had isolated increase in creatinine and decrease in glomerular filtration (GFR), 27% had AKI concomitantly with proteinuria, 18% had oliguria, and 13% had concomitant AKI with hematuria. Anuria was the rarest manifestation, occurring in only 4% of patients with DS. Temporary renal replacement therapy was needed in 30% of cases, and all but one patient fully recovered renal function. Mortality of DS in this cohort was 13%, which is higher than previously reported. Medication class, latency period, or pre-existing CKD were not found to be associated with higher mortality. More research, particularly prospective studies, is needed to better recognize the risks associated with renal injury in patients with DS. The development of disease-specific biomarkers would also be useful so DS with renal involvement can be easier distinguished from other eosinophilic diseases that might affect the kidney.

Hypoxia inducible factor-1α (HIF-1α) as an early predictor of acute hydrogen cyanamide (Dormex) poisoning

Hydrogen cyanamide (Dormex) is a plant growth regulator that is classified as a highly toxic poison. There are no definite investigations to help in its diagnosis and follow-up. This study aimed to investigate the role of hypoxia-inducible factor-1α (HIF-1α) in the diagnosis, prediction, and follow-up of Dormex-intoxicated patients. Sixty subjects were equally divided into two groups: group A, the control group, and group B, the Dormex group. Clinical and laboratory evaluations, including arterial blood gases (ABG), prothrombin concentration (PC), the international normalized ratio (INR), a complete blood count (CBC), and HIF-1α, were done on admission. CBC and HIF-1α were repeated for group B 24 and 48 h after admission to track abnormalities. Group B also had brain computed tomography (CT). Patients with abnormal CT scans were referred for brain magnetic resonance imaging (MRI). Significant differences in levels of HB, WBCs, and platelets were also detected in group B up to 48 h after admission, as white blood cells (WBCs) rose with time and hemoglobin (HB) and platelets diminished. The results described a highly significant difference in HIF-1α between the groups, and it depended on the clinical condition; therefore, it can be used in the prediction and follow-up of patients up to 24 h after admission.

Patch testing in Drug reaction with eosinophilia and systemic symptoms (DRESS): a literature review

The literature on positive patch test results in drug reaction with eosinophilia and systemic symptoms (DRESS) is reviewed. 105 drugs were identified that have together caused 536 positive patch tests in 437 patients suffering from DRESS. By far most reactions (n=145) were caused by carbamazepine, followed by amoxicillin, isoniazid, phenytoin, ethambutol, fluindione, phenobarbital, rifampicin, and ceftriaxone; 43 drugs each caused a single case only. The drug classes causing the highest number of reactions are anticonvulsants (39%), beta-lactam antibiotics (20%), antituberculosis agents (11%), non-beta-lactam antibiotics (6%) and iodinated contrast media (5%). The sensitivity of patch testing (percentage of positive reactions) is high for anticonvulsants (notably carbamazepine), beta-lactam antibiotics (notably amoxicillin) and possibly iodinated contrast media. Allopurinol and sulfasalazine frequently cause DRESS, but never give positive patch tests. Patch testing in DRESS appears to be safe, although mild recurrence of DRESS symptoms, mostly skin reactions, may not be rare. Multiple drug hypersensitivity was found to occur in 16% of all patients, but it is argued that the true frequency is (far) higher. Clinical aspects of DRESS, including diagnosing the disease and identifying culprit drugs (patch tests, intradermal tests, in vitro tests, challenge tests) are also provided, emphasizing the role of patch testing. This article is protected by copyright. All rights reserved.

Characterizing DRESS syndrome recurrence: a systematic review

Recurrence of DRESS syndrome is poorly characterized, and dermatologists must be prepared to predict, identify, and manage patients after treatment of the initial presentation. In this study, a primary literature search was conducted using PubMed, capturing all articles recording cases of DRESS syndrome recurrence. Forty-two articles were included for review comprising a total of 60 patients. The average age of patients was 46.3 years and time to recurrence was 123 days. Recurrent episodes presented more frequently with a higher fever and eosinophil absolute peak. Relapse was most often attributed to the introduction of a new medication (n = 18). Of the 17 cases in which outcome data were available, the survival rate of those experiencing recurrence was 71%. Viral reactivation with HHV-6 and organ involvement of the liver were frequently recorded complications. In essence, viral reactivation, severe internal organ involvement, and hematological abnormalities all portended a poorer prognosis in those experiencing DRESS syndrome recurrence. An adequate course of treatment should be maintained until clinical and laboratory parameters normalize, with a slow taper to minimize the likelihood of relapse in those most at risk.

Evaluation of Multiple Organ Dysfunction Score (MODS) and the Sequential Organ Failure Assessment (SOFA) score as in-hospital outcome predictors among cases of hydrogen cyanamide exposure: a cross-sectional study

Dormex is widely used as a plant growth regulator in developing countries such as Egypt as well as worldwide. Despite the widespread use of Dormex, little is known about the exact mechanism of action and toxic profile. The current study aims to outline the factors that predict in-hospital outcome and the need for intensive care unit (ICU) admission among the patients who presented with acute hydrogen cyanamide exposure as well as to evaluate the roles of the Multiple Organ Dysfunction Score (MODS) and the Sequential Organ Failure Assessment (SOFA) score as unfavorable outcome predictors. This is a retrospective cross-sectional study including all cases diagnosed with acute hydrogen cyanamide exposure who presented to the Tanta Poison Control Center during the past 6 years (January 1, 2015-January 1, 2020). Patient data were collected in a case report form, including the history of exposure, clinical data, laboratory investigations, and radiologic studies. Four scoring systems were carried out upon presentation: the Glasgow Coma Scale, poison severity score, MODS, and SOFA score. Thirty-five patients were enrolled in the current study. Most of the presented cases were males exposed unintentionally in an occupational setting. The mean participant age was 34.1 ± 15.51 years. The most common presenting complaints were throat irritation in all cases, vomiting and hallucinations presented equally in 68.6%, and headache occurred in 51.4%, whereas skin and mucous membrane burn was present in 40% of cases. Patients showing one or more of the following criteria were expected to have an urgent need for ICU admission: MODS >3.5, SOFA >4.5, length of hospital stay >30 hours, prothrombin time >14.75 seconds, serum glutamic pyruvic transaminase >67.5 U/L, and serum glutamic oxaloacetic transaminase >58.5 U/L. When the length of hospital stay was combined with the four scoring systems, only MODS yielded a significant prediction. Study results indicate that MODS and SOFA scores are considered excellent outcome predictors; MODS is more accurate, specific, and treatment independent, whereas the use of the SOFA score is more feasible with simple cardiovascular function assessment.

Genomic Risk Factors Driving Immune-Mediated Delayed Drug Hypersensitivity Reactions

Adverse drug reactions (ADRs) remain associated with significant mortality. Delayed hypersensitivity reactions (DHRs) that occur greater than 6 h following drug administration are T-cell mediated with many severe DHRs now associated with human leukocyte antigen (HLA) risk alleles, opening pathways for clinical prediction and prevention. However, incomplete negative predictive value (NPV), low positive predictive value (PPV), and a large number needed to test (NNT) to prevent one case have practically prevented large-scale and cost-effective screening implementation. Additional factors outside of HLA contributing to risk of severe T-cell-mediated DHRs include variation in drug metabolism, T-cell receptor (TCR) specificity, and, most recently, HLA-presented immunopeptidome-processing efficiencies via endoplasmic reticulum aminopeptidase (ERAP). Active research continues toward identification of other highly polymorphic factors likely to impose risk. These include those previously associated with T-cell-mediated HLA-associated infectious or auto-immune disease such as Killer cell immunoglobulin-like receptors (KIR), epistatically linked with HLA class I to regulate NK- and T-cell-mediated cytotoxic degranulation, and co-inhibitory signaling pathways for which therapeutic blockade in cancer immunotherapy is now associated with an increased incidence of DHRs. As such, the field now recognizes that susceptibility is not simply a static product of genetics but that individuals may experience dynamic risk, skewed toward immune activation through therapeutic interventions and epigenetic modifications driven by ecological exposures. This review provides an updated overview of current and proposed genetic factors thought to predispose risk for severe T-cell-mediated DHRs.

Development of a human herpesvirus 6 species-specific immunoblotting assay

In order to assess the full spectrum of human herpesvirus 6A (HHV-6A)- and HHV-6B-associated diseases, we sought to develop an HHV-6 species-specific serological assay based on immunoblot analysis. The immunodominant proteins encoded by open reading frame U11, p100 for HHV-6A (strain U1102) and 101K for HHV-6B (strain Z29), were selected to generate virus species-specific antigens. Recombinant p100 and 101K were produced in a prokaryotic expression system. The expression of these proteins was confirmed by using anti-His tag and 101K-specific monoclonal antibodies. HHV-6 species-specific antibodies were detected by immunoblotting in patient sera. Eighty-seven serum samples obtained from various subjects were utilized to determine the reliability of the method for clinical use. Ten of twelve exanthem subitum convalescent-phase sera reacted exclusively with 101K, whereas none of twelve acute-phase sera reacted with either protein. Two of three sera collected from HHV-6A-infected patients reacted with p100 and 101K. Although all five acute and convalescent-phase sera obtained from transplant recipients reacted exclusively with 101K, two of six convalescent-phase sera obtained from patients with drug-induced hypersensitivity syndrome reacted with both p100 and 101K. Of 38 sera obtained from healthy adults, 31 were positive for 101K antibody, while 4 reacted with both proteins. However, PCR analysis of peripheral blood mononuclear cells and saliva from these subjects did not detect HHV-6A DNA. In conclusion, this novel serological assay based on immunoblot analysis using recombinant HHV-6A p100 and HHV-6B 101K allowed us to discriminate between HHV-6A- and HHV-6B-specific antibodies.

The Link between Hypersensitivity Syndrome Reaction Development and Human Herpes Virus-6 Reactivation

Background. There are challenges in the clinical diagnosis of drug-induced injury and in obtaining information on the reactivation of human herpes viruses (HHV) during idiosyncratic adverse drug reactions. Objectives. (i) To develop a unified list of drugs incriminated in drug-induced hepatotoxicity and severe cutaneous reactions, in which drug hypersensitivity leads to HHV-6 reactivation and further complication of therapy and recovery and (ii) to supplement the already available data on reporting frequencies of liver- or skin-induced cases with knowledge of individual case reports, including HHV-6 reactivation and briefly introducing chromosomally integrated HHV-6. Data Sources and Extraction. Drugs identified as causes of (i) idiosyncratic reactions, (ii) drug-induced hypersensitivity, drug-induced hepatotoxicity, acute liver failure, and Stevens-Johnson syndrome, and (iii) human herpes virus reactivation in PubMed since 1997 have been collected and discussed. Results. Data presented in this paper show that HHV-6 reactivation is associated with more severe organ involvement and a prolonged course of disease. Conclusion. This analysis of HHV-6 reactivation associated with drug-induced severe cutaneous reactions and hepatotoxicity will aid in causality assessment and clinical diagnosis of possible life-threatening events and will provide a basis for further patient characterization and therapy.

The DRESS syndrome: a literature review

The Drug Reaction with Eosinophilia and Systemic Symptom (DRESS) is a severe adverse drug-induced reaction. Diagnosing DRESS is challenging due to the diversity of cutaneous eruption and organs involved. We used the RegiSCAR scoring system that grades DRESS cases as "no," "possible," "probable," or "definite" to classify cases reported in the literature. We also analyzed the clinical course and treatments of the cases. A total of 44 drugs were associated with the 172 cases reported between January 1997 and May 2009 in PubMed and MEDLINE. The most frequently reported drug was carbamazepine, and the vast majority of cases were classified as "probable/definite" DRESS cases. Hypereosinophilia, liver involvement, fever, and lymphadenopathy were significantly associated with "probable/definite" DRESS cases, whereas skin rash was described in almost all of the cases, including "possible cases." Culprit drug withdrawal and corticosteroids constituted the mainstay of DRESS treatment. The outcome was death in 9 cases. However, no predictive factors for serious cases were found. This better knowledge of DRESS may contribute to improve the diagnosis and management of this syndrome in clinical practice.

Drug-induced hypersensitivity syndrome due to carbapenem antibiotics

Drug-induced hypersensitivity syndrome (DIHS) is characterized by a serious adverse systemic reaction that usually appears after a 3-6-week exposure to certain drugs, for example, anticonvulsants. Many different precipitating factors have been reported, but the pathophysiology of DIHS remains unknown. However, reactivation of members of the human herpesvirus (HHV) family, and of HHV-6 in particular, has been reported in patients with DIHS. We report the case of a 64-year-old man who developed a generalized erythematous rash, fever, hepatic failure, lymphadenopathy and an increased number of atypical lymphocytes. In addition, reactivation of HHV-6 and cytomegalovirus (CMV) was demonstrated by real-time quantitative amplification by polymerase chain reaction. The patient was given a diagnosis of DIHS due to carbapenem antibiotics based on his clinical course, laboratory data, and results of lymphocyte-stimulation tests with various drugs. This is the first report, to our knowledge, of DIHS induced by carbapenem antibiotics.

The variable clinical picture of drug-induced hypersensitivity syndrome/drug rash with eosinophilia and systemic symptoms in relation to the eliciting drug

Drug-induced hypersensitivity syndrome (DIHS)/drug rash with eosinophilia and systemic symptoms (DRESS) is a life-threatening adverse reaction characterized by skin rashes, fever, leukocytosis with eosinophilia or atypical lymphocytosis, lymph node enlargement, and liver or renal dysfunction. The syndrome develops 2 to 6 weeks after initiation of administration of a specific drug. It has been demonstrated that various herpesvirus reactivations, in addition to human herpesvirus 6, contribute to internal organ involvement and the relapse of symptoms observed long after discontinuation of the causative drugs. A better understanding of the interplay in the development of DIHS/DRESS has implications for safer and more efficient treatment of this syndrome.

Hypereosinophilia associated with increased serum levels of carcinoembryonic antigen

We report a case of hypereosinophilia associated with increased serum levels of carcinoembryonic antigen (CEA). The patient developed fever, diarrhea, erythroderma and eosinophilia. Disorders known to be associated with eosinophilia were not detected. The typical malignant diseases related to a rise in CEA levels were not identified. The CEA value reached a maximum of 81.4 ng/ml a few weeks late for the peak of the eosinophilic count. Corticosteroid therapy was effective in improving clinical symptoms and the CEA values decreased in association with the improvement of those manifestations, suggesting a pathophysiological link between the disease activity of hypereosinophilia and the changes in CEA level.

The Herpes simplex virus gene Pol expressed in herpes-associated erythema multiforme lesions upregulates/activates SP1 and inflammatory cytokines

BACKGROUND/AIMS

Herpes-simplex-virus-associated erythema multiforme (HAEM) is characterized by lesional skin expression of the viral protein Pol and localized inflammation. The objective of this study is to examine the mechanism whereby Pol induces localized inflammation.

METHODS

A431 cells transfected with Pol or an empty vector and lesional skin from HAEM or drug-induced erythema multiforme patients were examined for expression of the transcription factor SP1 and SP1-regulated genes by immunoblotting, immunohistochemistry and immunofluorescence.

RESULTS

SP1, TGF-beta, p21(waf1) and Hsp27 were upregulated in A431 cells transfected with Pol but not the empty vector. Expression was further increased by exposure to IFN-gamma. Pol+ HAEM lesional skin expressed SP1, Hsp27, TGF-beta and p21(waf1). Normal skin and drug-induced erythema multiforme lesional skin were negative.

CONCLUSION

The data indicate that Pol activates SP1, causing upregulation of SP1 target genes (notably TGF-beta) involved in localized inflammation. Upregulation is potentiated by IFN-gamma.

Drug-induced hypersensitivity syndrome associated with a marked increase in anti-paramyxovirus antibody titers in a scleroderma patient

BACKGROUND

Drug-induced hypersensitivity syndrome (DIHS) is characterized by a severe multiorgan hypersensitivity reaction that usually appears after prolonged exposure to certain drugs and may be related to reactivation of herpes viruses. There have been few reports regarding the clinical association of DIHS with pathogens other than herpes viruses.

CASE SUMMARY

We report a case of scleroderma with DIHS associated with paramyxovirus infection. A 61-year-old man with early diffuse cutaneous scleroderma with myositis and progressive interstitial pneumonia developed generalized erythema with high fever 3 weeks after taking sulfamethoxazole/trimethoprim. The diagnosis of DIHS was made based on the patient's history of using an offending drug, clinical manifestations and laboratory data showing peripheral eosinophilia with the presence of atypical lymphocytes. Virological tests showed significant increases of antibody titers against mumps virus and parainfluenza virus type 2, which strongly suggested that paramyxovirus infection occurred during the clinical course of DIHS.

DISCUSSION

These findings suggest that paramyxovirus infection had contributed to the development of DIHS in this patient and that there is a need to seek evidence of other viral infections in some cases of DIHS, especially those without herpes virus reactivation/infection.

Human herpesvirus 6 subtype A-associated myocarditis with 'apical ballooning'

A 67-year-old woman who presented with acute chest pain is reported. Three days before admission, she suffered from a flu-like infection. Coronary angiography showed no coronary stenosis. Ventriculography showed moderately reduced left ventricular function characterized by the so-called 'apical ballooning'. Endomyocardial biopsies and polymerase chain reaction analysis of the plasma revealed an acute infection with human herpesvirus 6 subtype A. Histological and immunohistochemical analyses revealed myocarditis with areas of interstitial macrophages and fibrosis. The present case report links, for the first time, myocarditis with a human herpesvirus 6 subtype A infection and the appearance of apical ballooning.

Drug-Induced Hypersensitivity Syndrome due to Mexiletine Hydrochloride Associated with Reactivation of Human Herpesvirus 7

It has been suggested that reactivation of human herpesvirus 6 (HHV-6) infection may be involved in the pathogenesis of drug-induced hypersensitivity syndrome. We report a 45-year-old Japanese man who developed a generalized papuloerythematous rash, fever, hepatitis, lymphadenopathy and lymphocytosis with an increased number of atypical lymphocytes. He was diagnosed with DIHS due to mexiletine hydrochloride based on laboratory data, results of a patch test and the clinical course of his complaint, and was treated with systemic steroids. In order to determine whether HHV-6 or -7 was associated with the patient's disease, serological assays and PCR were carried out. Significant increases in antibody titers against HHV-6 and -7 were observed from day 12 to 24. From PCR analysis, none of the peripheral blood mononuclear cells or skin tissue samples contained HHV-6 DNA. All samples, however, were found to contain HHV-7 DNA. Reactivation of HHV-7 could be responsible for drug-induced hypersensitivity syndrome.

Reactivation of human herpesvirus (HHV) family members other than HHV-6 in drug-induced hypersensitivity syndrome

BACKGROUND

Drug-induced hypersensitivity syndrome (DIHS) is characterized by a severe multiorgan hypersensitivity reaction that usually appears after a 3-6-week exposure to certain drugs, including anticonvulsants. There are some reports showing that serum IgG levels often decrease at the early stage of DIHS. Reactivation of human herpesvirus (HHV)-6 has been reported in patients with DIHS, and some other DIHS patients showed reactivation of cytomegalovirus (CMV) or Epstein-Barr virus (EBV).

OBJECTIVES

To determine whether reactivation of HHV-6, HHV-7, CMV and/or EBV occurs in patients with DIHS.

METHODS

Titres of IgG and IgM antibodies to HHV-6 and HHV-7 were determined using an indirect immunofluorescence antibody assay on admission and at various times after admission. Anti-CMV IgG and IgM antibody titres and anti-EBV capsid antigen IgG, IgA, IgM, and EBV nuclear antigen and EBV early antigen IgG titres were determined by enzyme immunoassay. Polymerase chain reaction (PCR) procedures for HHV-6, HHV-7, CMV and EBV DNAs were performed using serum samples. IgG antibody titres to HHV-6, HHV-7, CMV and EBV were increased after the onset in seven, six, seven and two of seven patients, respectively. IgG antibody titres to HHV-6 and HHV-7 were elevated simultaneously 21-38 days after the onset.

RESULTS

IgG antibody titres to CMV and EBV were elevated 10-21 days after the elevation of HHV-6 and HHV-7 antibody titres. PCR showed that HHV-6, HHV-7, CMV and EBV DNAs became positive in six, five, seven and two of seven patients, respectively. HHV-6 and HHV-7 DNAs were detected 21-35 days after the onset, and CMV DNA was detected 10-21 days after detection of HHV-6 and HHV-7 DNAs.

CONCLUSION

The present study suggests that in addition to HHV-6 reactivation, reactivation of HHV-7, CMV and/or EBV may also occur following drug eruption in some patients with DIHS.

Carbamazepine-Induced Hypersensitivity Syndrome Occurring in a Photodistributed Pattern

A 76- year- old man was commenced on carbamazepine for partial seizures. This was followed by the development of a rash in an apparently photodistributed pattern, fever, lymphadenopathy, eosinophilia, abnormal liver function tests and atypical lymphocytosis fulfilling the criteria for drug-induced hypersensitivity syndrome. Discontinuation of carbamazepine and application of topical steroid resulted in clearance of the rash, normalization of liver function tests and improvement in eosinophilia. The photodistributed pattern in this case of carbamazepine-induced hypersensitivity syndrome is of interest.

Association of anticonvulsant hypersensitivity syndrome with Herpesvirus 6, 7

BACKGROUND

Anticonvulsant hypersensitivity syndrome (AHS) is one of the most severe forms of drug eruption with potentially lethal, and multiorgan involvement. Recently, it has been suggested that Human Herpesvirus (HHV) infection has been involved in this syndrome, although the pathogenesis of this syndrome remains still unclear.

METHODS

The objective of this study was to determine the clinical characteristics of AHS and the possible role of viral infection as a co-factor. We prospectively analyzed clinical, laboratory and virological findings for 23 cases of AHS. A viral study including viral serology and a polymerase chain reaction (PCR) was performed.

RESULTS

The most common anticonvulsant was carbamazepine (12) followed by phenytoin (6), phenobarbital (4) and gabapentin (1). All patients met fulfill the clinical criteria of AHS. Even though internal organ involvement such as liver (52%), kidney (34%), and lung (13%) has been observed, involvement of heart, lung, thyroid, muscle, pancreas, spleen, and brain was less frequent. We also noted two patients who died due to multiorgan failure. No association with viral infection including HSV, VZV, HHV-8, CMV, EBV, measles, rubella and parvovirus B19 was detected in the current series. Increased serum anti-HHV-6 IgG and HHV-7 titers and presence of HHV-6 and -7 DNA in serum, revealed by PCR analysis, suggested reactivation of HHV-6. In contrast to the control groups, DNA for HHV-6 was detected in serum in 5 out of the 23 patients while HHV-7 was seen in two patients. We found an evidence to link reactivation of HHV-6 or HHV-7 in the development of only carbamazepine-induced AHS.

CONCLUSIONS

We propose that some cases of AHS are accompanied by reactivation of not only HHV-6 but also HHV-7. HHV infection may contribute to the severity, prolongation, or relapse of AHS and may possibly have fatal consequences in some susceptible individuals receiving the anticonvulsants.

Several herpesviruses can reactivate in a severe drug-induced multiorgan reaction in the same sequential order as in graft-versus-host disease

BACKGROUND

Drug-induced hypersensitivity syndrome (DIHS) is a severe multiorgan systemic reaction. Numerous studies have linked reactivation of human herpesvirus (HHV)-6 with the development of DIHS. Recent articles have suggested that reactivation of other herpesviruses besides HHV-6 might also be involved in the development of DIHS. On the other hand, recent studies have provided evidence for a role of reactivation of various herpesviruses in the development of graft-versus-host disease (GVHD).

OBJECTIVES

We attempted to determine whether sequential herpesvirus reactivation could be detected in four patients with severe DIHS, as observed in patients with GVHD, and be coincident with various clinical manifestations that developed after discontinuation of the causative drugs.

METHODS

Detection and quantification of viral DNA [cytomegalovirus (CMV), Epstein-Barr virus (EBV), HHV-6 and HHV-7] in sequential blood samples were performed using real-time polymerase chain reaction assays, based on TaqMan technology.

RESULTS

In these patients, the cascade of virus reactivation initiated by HHV-6 or EBV extended to EBV or HHV-7, and eventually to CMV. Clinical manifestations of this syndrome followed by failure of various organs occurring despite discontinuation of the drug were coincident with these herpesvirus reactivations.

CONCLUSIONS

These results suggest that various herpesviruses can reactivate in the setting of severe drug reactions in a similar sequential order to that described in GVHD. The sequential reactivation of these herpesviruses is responsible for the development of multiorgan failure occurring after discontinuation of the causative drug.

Usefulness of a comprehensive PCR-based assay for human herpes viral DNA in blood mononuclear cell samples

Human herpes virus (HHV) is well known to reactivate in immunocompromised situations and plays an immunomodulatory role leading to indirect effects through viral replication to the host. The aim of this study was to determine the laboratory and clinical relevance of a comprehensive PCR-based assay for detecting eight HHVs, which are lymphotropic and cause disease in humans. Using 176 samples collected from 146 specimens of peripheral blood, 12 skin nodules, 11 lymph nodes and 7 others of patients who were suspected to have adult T cell leukemia (ATL), the PCR-based assay was validated to simultaneously detect one or more herpes viral DNA with two consensus primer sets. Although most samples were seropositive for either of the HHVs, only 50% of them were positive for either herpes viral DNA with EBV in 76%, HHV-6 in 14% and VZV in 9%. Furthermore, such a herpes viral DNA positive status was not always associated with clinical symptoms relating to the virus, implying active replication in the blood cells, but being asymptomatic. HHV-8 viral DNA, although Kaposi's sarcoma has been reported to be complicated with ATL, was not demonstrable. HHV-6B was detected only in HTLV-1 healthy carriers and ATL patients, and may imply a co-factor role with HTLV-1. This PCR-based assay provides a herpes viral infectious status compensatory for virus-serology and is a clinically relevant laboratory test, serving as a screening marker for active infection.

Down-Regulation of Basophil Function by Human CD200 and Human Herpesvirus-8 CD200

Human and rodent CD200 are recognized by the inhibitory CD200R, and these molecules play an important role in the regulation of the immune system. Several viruses, such as human herpesvirus-6 (HHV-6), HHV-7, and HHV-8, possess a CD200 homologue, suggesting that these viruses regulate the immune response via CD200R. In this study, we analyzed the effect of human CD200 and the viral CD200 homologues on human CD200R-expressing cells. We found that human CD200R is predominantly expressed on basophils in amounts higher than on other human peripheral blood leukocytes. Furthermore, the viral CD200 homologues as well as human CD200 were recognized by human CD200R, and the activation of basophils was down-regulated by these CD200 proteins. These results suggested that CD200R is an important regulatory molecule of basophil activation. In addition, the presence of CD200 homologues on several viruses suggests a potentially unique relationship between basophil function and viral infection.