Association between the DRB1*08032 histocompatibility antigen and methimazole-induced agranulocytosis in Japanese patients with Graves disease

Dose-dependent incidence of agranulocytosis in patients treated with methimazole and propylthiouracil

Agranulocytosis is a serious adverse effect of methimazole (MMI) and propylthiouracil (PTU), and although there have been reports suggesting a dose-dependent incidence in relation to both drugs, the evidence has not been conclusive. The objective of our study was to determine whether the incidences of agranulocytosis induced by MMI and PTU exhibit dose-dependency. The subjects were 27,784 patients with untreated Graves' disease, 22,993 of whom were on an antithyroid drug treatment regimen for more than 90 days. Within this subset, 18,259 patients had been treated with MMI, and 4,734 had been treated with PTU. The incidence of agranulocytosis according to dose in the MMI group was 0.13% at 10 mg/day, 0.20% at 15 mg/day, 0.32% at 20 mg/day, and 0.47% at 30 mg/day, revealing a significant dose-dependent increase. In the PTU group, there were 0 cases of agranulocytosis at doses of 125 mg/day and below, 0.33% at 150 mg/day, 0.31% at 200 mg/day, and 0.81% at 300 mg/day, also revealing a significant dose-dependent increase. The incidence of agranulocytosis at MMI 15 mg and PTU 300 mg, i.e., at the same potency in terms of hormone synthesis inhibition, was 0.20% and 0.81%, respectively, and significantly higher in the PTU group. Our findings confirm a dose-dependent increase in the incidence of agranulocytosis with both drugs, but that at comparable thyroid hormone synthesis inhibitory doses PTU has a considerably higher propensity to induce agranulocytosis than MMI does.

Antithyroid drug-induced leukopenia and G-CSF administration: a long-term cohort study

Although antithyroid drug (ATD)-induced agranulocytosis is a significant concern, its risks associated with long-term use and re-administration are not fully elucidated. Therefore, we performed this study to determine the incidence of ATD-induced leukopenia and G-CSF administration using administrative claims database. Retrospective cohort study. This study was performed using the DeSC Japanese administrative claims database. A total of 12,491 patients with newly diagnosed Graves' disease (GD) who received methimazole or propylthiouracil between April 2014, and February 2021 among 3.44 million patients in the database were included in the study. We measured the six-year incidence of leukopenia and granulocyte colony-stimulating factor (G-CSF) administration. The incidence of leukopenia and G-CSF administration was 1.34% (168 patients) and 0.30% (38 patients), respectively. Leukopenia had a dose-dependent and biphasic incidence. The incidence of leukopenia and G-CSF administration was 37.2 (0.7%) and 8.0 (0.2%) per 1000 person-years during the first 72 days of ATD initiation, whereas it was 3.1 and 0.7 per 1000 person-years during the subsequent 6 years, respectively. The incidence of both outcomes was comparable between first administration and re-administration of ATD. The incidence of ATD-induced leukopenia and G-CSF administration was high in the first 72 days, with a reduced risk for at least 6 years thereafter. The incidence was similar between first administration and re-administration. ATD, a standard therapy, is often administered for a long period; therefore, our findings can guide the treatment of GD.

Safety of Antithyroid Drugs in Avoiding Hyperglycemia or Hypoglycemia in Patients With Graves' Disease and Type 2 Diabetes Mellitus: A Literature Review

Graves' disease (GD) may increase the difficulty of glucose control in patients with type 2 diabetes mellitus (T2DM). Therefore, selecting a drug with limited blood glucose side effects is an important issue in patients with T2DM and GD. Antithyroid drugs (ATDs) including propylthiouracil (PTU), methimazole, and carbimazole are commonly prescribed for the treatment of GD. Here, we review and summarize the literature from the last 10 years and discuss the effects of current ATDs used for GD for blood glucose control in patients with T2DM. A search of the literature published between January 1, 2012 and December 1, 2022 was conducted using three major medical databases: Google Scholar, Ovid Medline, and Scopus. An initial search was conducted on PubMed using the MeSH terms "propylthiouracil," "methimazole," "carbimazole," and "hyperglycemia" or "hypoglycemia" in academic databases. All articles included "Graves' disease" and "type 2 diabetes mellitus" in the title. Based on the results of previous studies, the hyperglycemic and hypoglycemic side effects of ATDs can be explained by several possible mechanisms. The most widely accepted hypothesis is that sulfhydryl group drugs (e.g., methimazole and carbimazole) cleave the disulfide bond of insulin and enhance its immunogenicity, resulting in hypoglycemia. Moreover, some reports have indicated that methimazole is associated with hypoglycemia; therefore, if the patient has a history of autoimmune diseases, it is necessary to consider whether to change drugs or actively track the production of autoimmune antibodies. In non-diabetic and diabetic patients with GD, the hyperglycemic and hypoglycemic side effects of PTU (on glycemic variation) were less than that of thiamazole. However, as relatively few reports have investigated the side effects of blood sugar changes, further research is necessary to confirm these effects. In addition to autoimmune diseases, drug side effects may need to be considered. These findings provide considerations for clinicians to select more appropriate ATDs for patients with GD and T2DM, and implement improved care guidelines.

Delayed Drug Hypersensitivity Reactions: Molecular Recognition, Genetic Susceptibility, and Immune Mediators

Drug hypersensitivity reactions are classified into immediate and delayed types, according to the onset time. In contrast to the immediate type, delayed drug hypersensitivity mainly involves T lymphocyte recognition of the drug antigens and cell activation. The clinical presentations of such hypersensitivity are various and range from mild reactions (e.g., maculopapular exanthema (MPE) and fixed drug eruption (FDE)), to drug-induced liver injury (DILI) and severe cutaneous adverse reactions (SCARs) (e.g., Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP)). The common culprits of delayed drug hypersensitivity include anti-epileptics, antibiotics, anti-gout agents, anti-viral drugs, etc. Delayed drug hypersensitivity is proposed to be initiated by different models of molecular recognition, composed of drug/metabolite antigen and endogenous peptide, HLA presentation, and T cell receptor (TCR) interaction. Increasing the genetic variants of HLA loci and drug metabolic enzymes has been identified to be responsible for delayed drug hypersensitivity. Furthermore, preferential TCR clonotypes, and the activation of cytotoxic proteins/cytokines/chemokines, are also involved in the pathogenesis of delayed drug hypersensitivity. This review provides a summary of the current understanding of the molecular recognition, genetic susceptibility, and immune mediators of delayed drug hypersensitivity.

A single-tube multiplex real-time PCR for HLA-B*38:02 genotype by detecting highly specific SNPs

Purpose: HLA-B*38:02 is closely related to carbimazole/methimazole-induced agranulocytosis. This study aimed to develop and validate a rapid and economical method for HLA-B*38:02 genotyping. Methods: A single-tube multiplex real-time PCR detection system comprising amplification refractory mutation system primers and TaqMan probes was established for HLA-B*38:02 genotyping. Sequence-based typing was applied to validate the accuracy of the assay. Results: The accuracy of the assay was 100% for HLA-B*38:02 genotyping. The detection limit of the new method was 0.05 ng DNA. The positive rate of HLA-B*38:02 in the Han (8%, n = 100), Bouyei (17.8%, n = 90) and Tibetan (12.7%, n = 110) populations was significantly higher than that in the Uighur population (1%, n = 100) (p < 0.05). Conclusion: The proposed method is rapid and reliable for HLA-B*38:02 screening in a clinical setting.

Concomitant methimazole-induced agranulocytosis and cholestatic jaundice in a young woman

A woman in her 30s presented to the emergency department with new-onset sore throat and fever. She had recently been diagnosed with Graves' disease 3 months prior. As a result, she was initiated on atenolol and methimazole for management. Her methimazole dosing had been stable at 15 mg daily for the month prior to presentation. Investigation revealed severe neutropenia and jaundice. She was found to have concomitant agranulocytosis and cholestatic jaundice secondary to methimazole.Methimazole was discontinued on admission and the patient received granulocyte colony-stimulating factor for an absolute neutrophil count (ANC) of zero. She was placed on broad-spectrum antibiotics and intravenous steroids for epiglottic and supraglottic oedema noted on bedside laryngoscopy. ANC and bilirubin improved over a 2-week hospital course. She was discharged on a temporary regimen of propranolol, dexamethasone and potassium iodide until she was able to undergo successful thyroidectomy for definitive management of Graves' disease outpatient.

A case of methimazole-induced acute pancreatitis with an HLA allele causing antithyroid drug-induced agranulocytosis

Among the side effects of methimazole (MMI) for the treatment of Graves’ disease, MMI-induced acute pancreatitis (MIP) is a rare adverse reaction, with only 7 cases being reported to date. However, 2 large-scale population-based studies recently revealed that the risk of MIP was significantly higher, ranging from 0.02% to 0.56%. Although MIP is common in middle-aged and elderly Asian women, its pathogenesis remains largely unknown. We herein present a case of a 72-year-old Japanese woman with Graves’ disease who developed MIP 12 days after the initiation of MMI. The MMI was discontinued, the patient was switched to propylthiouracil (PTU) therapy, and pancreatitis gradually resolved. Serological human leukocyte antigen (HLA) typing identified HLA-DRB1*08:03:02. This HLA allele was previously detected in a patient with MIP and is one of the major risk factors for agranulocytosis induced by antithyroid drugs, including PTU as well as MMI. In cases of MIP, PTU is being considered as an alternative to MMI; however, its safety needs further investigation and patients require close monitoring after the switch to PTU. Further studies are warranted, particularly on the relationship between MIP and the presence of HLA alleles causing antithyroid drug-induced agranulocytosis.

Evolving Role of Pharmacogenetic Biomarkers to Predict Drug-Induced Hematological Disorders

ABSTRACT

Drug-induced hematological disorders constitute up to 30% of all blood dyscrasias seen in the clinic. Hematologic toxicity from drugs may range from life-threatening marrow aplasia, agranulocytosis, hemolysis, thrombosis to mild leukopenia, and thrombocytopenia. Pathophysiologic mechanisms underlying these disorders vary from an extension of the pharmacological effect of the drug to idiosyncratic and immune-mediated reactions. Predicting these reactions is often difficult, and this makes clinical decision-making challenging. Evidence supporting the role of pharmacogenomics in the management of these disorders in clinical practice is rapidly evolving. Despite the Clinical Pharmacology Implementation Consortium and Pharmacogenomics Knowledge Base recommendations, few tests have been incorporated into routine practice. This review aims to provide a comprehensive summary of the various drugs which are implicated for the hematological adverse events, their underlying mechanisms, and the current evidence and practical recommendations to incorporate pharmacogenomic testing in clinical care for predicting these disorders.

Rare case of pancrelipase therapy-induced neutropaenia

A 61-year-old man was transferred to our facility from an outside hospital due to refractory neutropaenia of unknown aetiology. The patient presented to the referring hospital with a 5-day history of worsening diarrhoea and abdominal pain. Initial lab results at presentation showed severe neutropaenia with an absolute neutrophil count of 0. Investigations included a bone marrow biopsy which showed slightly hypocellular marrow with near absence of granulocytic precursors. A CT without contrast showed evidence of chronic pancreatitis and acute colitis. The patient's neutropaenia persisted despite granulocyte colony-stimulating factor therapy. The patient was, thus, transferred to our facility for a higher level of care. At our facility, the patient had rapid correction of neutropaenia after discontinuation of pancrelipase therapy. The patient's abdominal pain and diarrhoea also improved while off pancrelipase. Neutropaenia has completely resolved 6 weeks after discharge without any further therapy.

HLA-B*39:01:01 is a novel risk factor for antithyroid drug-induced agranulocytosis in Japanese population

Antithyroid drug (ATD) is a mainstay of Graves' disease (GD). About 0.1-0.5% of patients with GD treated with ATD exhibit ATD-induced agranulocytosis, which is characterized by severe reduction of circulating neutrophils. Immune-mediated responses have been proposed as a possible mechanism for the pathogenesis of ATD-induced agranulocytosis. Although it has been reported that the HLA class II allele (HLA-DRB1*08:03) was associated with ATD-induced agranulocytosis in multiple populations, the entire HLA region have not been explored in Japanese. Therefore, we performed HLA sequencing for 10 class I and 11 class II genes in 87 patients with ATD-induced agranulocytosis and 384 patients with GD who did not show ATD-induced agranulocytosis. By conducting case-control association studies at the HLA allele and haplotype levels, we replicated the association between HLA-DRB1*08:03:02 and ATD-induced agranulocytosis (P = 5.2 × 10^-7, odds ratio = 2.80), and identified HLA-B*39:01:01 as an independent risk factor (P = 1.4 × 10^-3, odds ratio = 3.35). To verify reproducibility of the novel association of HLA-B*39:01:01, we reanalyzed allele frequency data for HLA-B*39:01:01 from previous case-control association studies. The association of HLA-B*39:01:01 was significantly replicated in Chinese (P = 9.0 × 10^-3), Taiwanese (P = 1.1 × 10^-3), and European populations (P = 5.2 × 10^-4). A meta-analysis combining results from the previous and current studies reinforced evidence of the association between HLA-B*39:01:01 and ATD-induced agranulocytosis (P_meta = 1.2 × 10^-9, pooled OR = 3.66, 95% CI; 2.41-5.57). The results of this study will provide a better understanding of the pathogenesis of ATD-induced agranulocytosis in the context of HLA-mediated hypersensitivity reactions.

Idiosyncratic Drug-Induced Neutropenia and Agranulocytosis in Elderly Patients

Agranulocytosis is a rare, but serious and life-threatening hematologic disorder in elderly patients. Idiosyncratic drug-induced agranulocytosis (IDIA) has been classically defined by a neutrophil count below 0.5 × 10⁹/L. The annual incidence of IDIA in Europe is about 1.6–9.2 cases per million inhabitants. Increasing age and female sex have been considered as risk factors for the development of this condition. Besides, it is well known that older people take on average more drugs than younger people. This condition is most often associated with the intake of antibacterial agents, antiplatelets, antithyroids, antipsychotics, antiepileptics and nonsteroidal anti-inflammatory drugs (NSAIDs). Initially, agranulocytosis may present without symptoms, but may quickly progress to a severe infection and sepsis. The causative drug should be immediately stopped. In febrile patients, blood cultures and where indicated, site-specific cultures should be obtained and early treatment with empirical broad-spectrum antibiotics started. Even with adequate treatment, the mortality rate is higher in elderly patients reaching up to 20%. Hematopoietic growth factors have proven to be useful as they shorten the duration of neutropenia. However, data on neutropenia and agranulocytosis in the elderly meeting the criteria of evidence-based medicine are still poor in the literature. This review analyzes the results of our experience as well as other published studies of the universal literature.

Associations of HLA genotypes with antithyroid drug-induced agranulocytosis: A systematic review and meta-analysis of pharmacogenomics studies

AIMS

Antithyroid drug (ATD)-induced agranulocytosis is a life-threatening adverse drug reaction. Previous studies suggested that HLA genotypes may play an important role in ATD-induced agranulocytosis. To examine the associations between HLA genotypes and ATD-induced agranulocytosis, we conducted a systematic review and meta-analysis of pharmacogenomics studies.

METHODS

We searched the MEDLINE, Embase and CENTRAL databases on 16 June 2018 for case-control studies on the associations between HLA genotypes with ATD-induced agranulocytosis. The Newcastle-Ottawa scale was used to evaluate the risk of bias of included studies. We conducted random-effects model meta-analysis to obtain pooled odds ratios (ORs) with 95% confidence intervals (CIs) to determine the associations between HLA genotypes and ATD-induced agranulocytosis.

RESULTS

We included 5 studies with 142 ATD-induced agranulocytosis cases, 1529 matched ATD-tolerant controls and 5945 healthy controls. The risk of bias of included studies was generally low. ATD-induced agranulocytosis was associated with HLA-B*27:05 (OR 10.97; 95% CI 0.75-159.99), HLA-B*38:02 (OR 19.85; 95% CI 7.94-49.57) and HLA-DRB1*08:03 (OR 5.29; 95% CI 3.44-8.14). After excluding propylthiouracil, the associations of ATD-induced agranulocytosis with HLA-B*27:05 and HLA-B*38:02 were strengthened (OR being 20.61 (95% CI 5.21-81.58) and 40.59 (95% CI 13.24-124.47), respectively). The associations of ATD-induced agranulocytosis with HLA-B*27:05, HLA-B*38:02 and HLA-DRB1*08:03 remained significant when compared to population controls (OR being 7.37 (95% CI 3.86-14.07), 36.43 (95% CI 12.80-103.70) and 5.42 (95% CI 2.36-12.47), respectively). HLA-B*27:05, HLA-B*38:02, and HLA-DRB1*08:03 alleles were associated with ATD-induced agranulocytosis, especially in carbimazole/methimazole-induced agranulocytosis.

CONCLUSIONS

HLA-B*27:05, HLA-B*38:02 and HLA-DRB1*08:03 alleles were associated with ATD-induced agranulocytosis, especially in carbimazole/methimazole-induced agranulocytosis.

Increased Risk of Antithyroid Drug Agranulocytosis Associated with Amiodarone-Induced Thyrotoxicosis: A Population-Based Cohort Study

BACKGROUND

Agranulocytosis occurs in 0.2-0.5% of patients treated with the antithyroid drugs (ATDs) methimazole and propylthiouracil. The objectives of this study were to evaluate the risk of ATD-related agranulocytosis in patients with amiodarone-induced thyrotoxicosis (AIT), and to compare it with the agranulocytosis risk in patients with thyrotoxicosis due to other etiologies treated with ATDs.

METHODS

This was a retrospective cohort study. Participants were 14,781 adult patients with thyrotoxicosis, newly treated with an ATD between January 1, 2002, and December 31, 2015. Among them were 593 patients treated by ATDs due to AIT. The main outcome measures were incidence rates and crude and adjusted hazard ratios using univariate and multivariable Cox regression models for ATD-related agranulocytosis within one year of treatment initiation, in association with AIT.

RESULTS

Agranulocytosis occurred in 28 (0.19%) of patients newly treated with methimazole or propylthiouracil during the first year of follow-up. Of these 28 patients, 8/593 (1.35%) were AIT patients and 20/14,188 (0.14%) were thyrotoxic patients that was not AIT related (p < 0.001). Incidence rates were 22 (9.47-43.36) cases/1000 person-years of follow-up in AIT, and 1.79 (1.09-2.76)/1000 person-years of follow-up in non-AIT thyrotoxicosis (p < 0.0001). In univariate Cox regression analysis, risk for ATD agranulocytosis associated with AIT was 9.71 (4.28-22.05) compared to the risk in non-AIT thyrotoxicosis. In a multivariable model, adjusting for age, sex, body mass index, smoking history, year of cohort entry, diabetes mellitus, hypertension, renal failure, beta blockers, calcium channel blockers, anti-aggregants, and dose of ATDs, the risk associated with AIT was 5.70 (2.14-15.21). In a model adjusted for a propensity score to receive amiodarone, risk for ATD agranulocytosis associated with AIT was 6.32 (1.22-32.70).

CONCLUSIONS

ATD use is associated with a higher risk for agranulocytosis in patients with AIT.

Graves' disease: Introduction, epidemiology, endogenous and environmental pathogenic factors

Graves' disease is the most frequent cause of hyperthyroidism. Many questions remain about the choice of diagnostic evaluations and treatment strategy according to clinical context (age, gender, pregnancy, etc.) and about the best management of the main extrathyroidal complication that is Graves orbitopathy. The exact pathogenic mechanisms are not fully clear. They associate genetic factors, interactions between endogenous and environmental factors, and immune system dysregulation. Graves' orbitopathy is one of the consequences of this partial understanding. Iatrogenic Graves' disease induced by the new targeted therapies are described and could help to better understand the molecular pathways involved in the disease and to develop new therapeutic approaches.

Thyrotropin receptor antibodies and a genetic hint in antithyroid drug-induced adverse drug reactions

BACKGROUND

Antithyroid drugs (ATDs) are known to cause various adverse drug reactions (ADRs) that can lead to treatment complexity and unpredictable risks. With the aim of ensuring safer drug use, we assessed whether thyrotropin receptor antibody (TRAb) titers are associated with ATD-induced cutaneous reactions and/or hepatotoxicity, and examined potential genetic predisposition factors.

METHODS

We compared TRAb titers of 37 Graves' disease (GD) patients who had experienced carbimazole/methimazole-induced cutaneous reactions and/or hepatotoxicity with those of 40 normal individuals, or 78 GD patients without the aforementioned ATD-induced ADRs. We performed a genome-wide association study and/or human leukocyte antigen genotyping on GD patients [first stage (chart reviews): 24 cases with ADRs and 423 controls; second stage (actively recruited): 45 cases with ADRs and 137 controls].

RESULTS

For patients with Graves' hyperthyroidism, individuals with higher TRAb titers showed a predisposition to carbimazole/methimazole-induced cutaneous reactions and/or hepatotoxicity, with an estimated odds ratio of 5.19 (cut-off value: 64%). Potential associations with the rs144542704 and rs61893841 on chromosomes 17 and 11, respectively, warrant further genetic association analysis.

CONCLUSION

Our findings support the use of carbimazole/methimazole in patients with low TRAb titers to ensure safer drug use. The identified genetic associations warrant further research.

Recent updates and challenges on the regulation of precision medicine: The United States in perspective

The rapid progress in "omics", such as genomics, metabolomics, microbiomics, has paved the path for precision medicine and revolutionized the development of drugs and devices promising to meet unmet medical needs. The aim of the present study was to investigate the current regulatory framework established by the United States Food and Drug Administration (USFDA) and to identify challenges and concerns through study of related literatures in the PubMed database. We found that efforts were made to facilitate the implementation of precision medicine through organizational reform, publication of guidance documents, and continuous post-market surveillance. The challenges identified included the critical, fundamental structural requirements of databases, essential regulatory considerations for market approval, and the appropriate clinical use such as whole genomic sequencing tests especially for a newborn or even fetus. These issues are worth further research to devise an integral approach involving scientific, ethical, legal, and social considerations.

Biomarkers of adverse drug reactions

Adverse drug reactions can be caused by a wide range of therapeutics. Adverse drug reactions affect many bodily organ systems and vary widely in severity. Milder adverse drug reactions often resolve quickly following withdrawal of the casual drug or sometimes after dose reduction. Some adverse drug reactions are severe and lead to significant organ/tissue injury which can be fatal. Adverse drug reactions also represent a financial burden to both healthcare providers and the pharmaceutical industry. Thus, a number of stakeholders would benefit from development of new, robust biomarkers for the prediction, diagnosis, and prognostication of adverse drug reactions. There has been significant recent progress in identifying predictive genomic biomarkers with the potential to be used in clinical settings to reduce the burden of adverse drug reactions. These have included biomarkers that can be used to alter drug dose (for example, Thiopurine methyltransferase (TPMT) and azathioprine dose) and drug choice. The latter have in particular included human leukocyte antigen (HLA) biomarkers which identify susceptibility to immune-mediated injuries to major organs such as skin, liver, and bone marrow from a variety of drugs. This review covers both the current state of the art with regard to genomic adverse drug reaction biomarkers. We also review circulating biomarkers that have the potential to be used for both diagnosis and prognosis, and have the added advantage of providing mechanistic information. In the future, we will not be relying on single biomarkers (genomic/non-genomic), but on multiple biomarker panels, integrated through the application of different omics technologies, which will provide information on predisposition, early diagnosis, prognosis, and mechanisms. Impact statement • Genetic and circulating biomarkers present significant opportunities to personalize patient therapy to minimize the risk of adverse drug reactions. ADRs are a significant heath issue and represent a significant burden to patients, healthcare providers, and the pharmaceutical industry. • This review details the current state of the art in biomarkers of ADRs (both genetic and circulating). There is still significant variability in patient response which cannot be explained by current knowledge of genetic risk factors for ADRs; however, we discussed how specific advances in genomics have the potential to yield better and more predictive models. • Many current clinically utilized circulating biomarkers of tissue injury are valid biomarkers for a number of ADRs. However, they often give little insight into the specific cell or tissue subtype which may be affected. Emerging circulating biomarkers with potential to provide greater information on the etiology/pathophysiology of ADRs are described.

HLAs: Key regulators of T-cell-mediated drug hypersensitivity

Adverse drug reactions (ADR) can be broadly categorised as either on-target or off-target. On-target ADRs arise as a direct consequence of the pharmacological properties of the drug and are therefore predictable and dose-dependent. On-target ADRs comprise the majority (>80%) of ADRs, relate to the drug's interaction with its known pharmacological target and are a result of a complex interplay of genetic and ecologic factors. In contrast, off-target ADRs, including immune-mediated ADRs (IM-ADRs), are due to unintended pharmacological interactions such as inadvertent ligation of host cell receptors or non-pharmacological interactions mediated through an adaptive immune response. IM-ADRs can be classified according to the primary immune cell involved and include B-cell-mediated (Gell-Coombs type I-III reactions) and T-cell-mediated (Gell-Coombs type IV or delayed hypersensitivity) reactions. IM-ADRs mediated by T cells are associated with phenotypically distinct clinical diagnoses and can vary from a mild delayed rash to a life-threatening cutaneous, systemic or organ disease, such as Stephen Johnson syndrome/toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms and drug-induced liver disease. T-cell-mediated ADRs are strongly linked to the carriage of particular HLA risk alleles which are in the case of abacavir hypersensitivity and HLA-B*57:01 has led to translation into the clinic as a routine screening test. In this review, we will discuss the immunogenetics and pathogenesis of IM-ADRs and how HLA associations inform both pre-drug screening strategies and mechanistic understanding.

Association of HLA-B∗38:02 with Antithyroid Drug-Induced Agranulocytosis in Kinh Vietnamese Patients

BACKGROUND

HLA-B^∗38:02 has been shown to be associated with antithyroid drug-induced agranulocytosis in Asian patients.

METHODS

HLA-B^∗38:02 was analyzed by sequence-based typing in 21 patients who developed antithyroid drug-induced agranulocytosis and in 81 controls.

RESULTS

Frequency of HLA-B^∗38:02 was 52.4% in agranulocytosis patients compared to 3.7% in controls (OR = 28.6, 95% CI = 6.8-120.2).

CONCLUSIONS

HLA-B^∗38:02 is a significant risk factor for agranulocytosis in Kinh Vietnamese patients treated with antithyroid drug.

Non-chemotherapy drug-induced neutropenia: key points to manage the challenges

Non-chemotherapy idiosyncratic drug-induced neutropenia (IDIN) is a relatively rare but potentially fatal disorder that occurs in susceptible individuals, with an incidence of 2.4 to 15.4 cases per million population. Affected patients typically experience severe neutropenia within several weeks to several months after first exposure to a drug, and mortality is ∼5%. The drugs most frequently associated with IDIN include metamizole, clozapine, sulfasalazine, thiamazole, carbimazole, amoxicillin, cotrimoxazole, ticlopidine, and valganciclovir. The idiosyncratic nature of IDIN, the lack of mouse models and diagnostic testing, and its low overall incidence make rigorous studies to elucidate possible mechanisms exceptionally difficult. An immune mechanism for IDIN involving neutrophil destruction by hapten (drug)-specific antibodies and drug-induced autoantibodies is frequently suggested, but strong supporting evidence is lacking. Although laboratory testing for neutrophil drug-dependent antibodies is rarely performed because of the complexity and low sensitivity of tests currently in use, these assays could possibly be enhanced by using reactive drug metabolites in place of the parent drug. Patients typically experience acute, severe neutropenia, or agranulocytosis (<0.5 × 10⁹ neutrophils/L) and symptoms of fever, chills, sore throat, and muscle and joint pain. Diagnosis can be difficult, but timely recognition is critical because if left untreated, there is an increase in mortality. Expanded studies of the production and mechanistic role of reactive drug metabolites, genetic associations, and improved animal models of IDIN are essential to further our understanding of this important disorder.

Sulfasalazine-Induced Agranulocytosis Is Associated With the Human Leukocyte Antigen Locus

Agranulocytosis is a serious, although rare, adverse reaction to sulfasalazine, which is used to treat inflammatory joint and bowel disease. We performed a genome-wide association study comprising 9,380,034 polymorphisms and 180 HLA alleles in 36 cases of sulfasalazine-induced agranulocytosis and 5,170 population controls. Sulfasalazine-induced agranulocytosis was significantly associated with the HLA region on chromosome 6. The top hit (rs9266634) was located close to HLA-B, odds ratio (OR) 5.36 (95% confidence interval (CI) (2.97, 9.69) P = 2.55 × 10^-8 ). We HLA-sequenced a second cohort consisting of 40 cases and 142 treated controls, and confirmed significant associations with HLA-B*08:01, OR = 2.25 (95% CI (1.02, 4.97) P = 0.0439), in particular the HLA-B*08:01 haplotype HLA-DQB1*02:01-DRB1*03:01-B*08:01-C*07:01, OR = 3.79 (95% CI (1.63, 8.80) P = 0.0019), and with HLA-A*31:01, OR = 4.81 (95% CI (1.52, 15.26) P = 0.0077). The number needed to test for HLA-B*08:01 and HLA-A*31:01 to avoid one case was estimated to be 1,500. We suggest that intensified monitoring or alternative treatment should be considered for known carriers of HLA-B*08:01 or HLA-A*31:01.

Association of HLA-B and HLA-DRB1 polymorphisms with antithyroid drug-induced agranulocytosis in a Han population from northern China

Antithyroid drug (ATD)-induced agranulocytosis is associated with human leukocyte antigen (HLA) and nearby genes in Southeast Asian and European populations. The susceptibility of the Han population from northern China to ATD-induced agranulocytosis has not been reported. We evaluated the associations of genetic variants at the HLA-B and HLA-DRB1 loci and 32 candidate single nucleotide polymorphisms (SNPs) with agranulocytosis in 29 patients with ATD-induced agranulocytosis and in 140 patients with Graves’ disease (GD) as controls. All subjects were of Han descent from northern China. HLA-B*27:05 (P = 1.10 × 10⁻⁴), HLA-B*38:02 (P = 2.41 × 10⁻⁴) and HLA-DRB1*08:03 (P = 1.57 × 10⁻³) were susceptibility HLA variants for ATD-induced agranulocytosis. All subjects carrying the HLA-B*27:05 allele had agranulocytosis. The odds ratios (ORs) comparing allele carriers to non-carriers were 66.24 (95% confidence interval (CI): 3.54–1239.66) for HLA-B*27:05, 7.525 (95% CI: 2.294–24.68) for HLA-B*38:02 and 4.316 (95% CI: 1.56–11.93) for HLA-DRB1*08:03. Two SNPs, rs2596487 (OR = 4.196, 95% CI = 2.086–8.441, P = 2.08 × 10⁻⁵) and rs2228391 (OR = 3.621, 95% CI = 1.596–8.217, P = 1.2 × 10⁻³), were independently associated with ATD-induced agranulocytosis. Subjects carrying the ‘A’ allele of rs1811197 or HLA-B*38:02 showed lower minimum granulocyte counts than non-carriers (P = 4.74 × 10⁻⁴ and P = 7.39 × 10⁻⁴, respectively). Our findings support the association between genetic variations of HLA-B and HLA-DRB1 with ATD-induced agranulocytosis in a Han population from northern China.

Rare NOX3 Variants Confer Susceptibility to Agranulocytosis During Thyrostatic Treatment of Graves' Disease

Agranulocytosis is a rare and serious adverse effect of antithyroid drugs, with unknown etiology. The present study aimed to uncover genetic susceptibility and underlying mechanisms of antithyroid drug-induced agranulocytosis (ATDAC). We studied two independent families with familial Graves' disease, of which several members developed ATDAC. In addition, six sporadic ATDAC patients with Graves' disease were investigated. Whole exome sequencing analysis of affected and unaffected family members was performed to identify genetic susceptibility variants for ATDAC, followed by functional characterization of primary granulocytes from patients and unrelated healthy controls. Whole exome sequencing, cosegregation analysis, and stringent selection criteria of candidate gene variants identified NOX3 as a genetic factor related to ATDAC. Functional studies revealed increased apoptosis of methimazole-treated granulocytes from patients carrying NOX3 variants. In conclusion, genetic variants in NOX3 may confer susceptibility to antithyroid drug-induced apoptosis of granulocytes. These findings contribute to the understanding of the mechanisms underlying ATDAC.

Pharmacogenetics and Predictive Testing of Drug Hypersensitivity Reactions

Adverse drug reactions adverse drug reaction (ADR) occur in approximately 17% of patients. Avoiding ADR is thus mandatory from both an ethical and an economic point of view. Whereas, pharmacogenetics changes of the pharmacokinetics may contribute to the explanation of some type A reactions, strong relationships of genetic markers has also been shown for drug hypersensitivity belonging to type B reactions. We present the classifications of ADR, discuss genetic influences and focus on delayed-onset hypersensitivity reactions, i.e., drug-induced liver injury, drug-induced agranulocytosis, and severe cutaneous ADR. A guidance how to read and interpret the contingency table is provided as well as an algorithm whether and how a test for a pharmacogenetic biomarker should be conducted.

Genetic variants associated with antithyroid drug-induced agranulocytosis: a genome-wide association study in a European population

BACKGROUND

Drug-induced agranulocytosis is a potentially life-threatening adverse reaction. Genome-wide association studies (GWASs) in ethnic Chinese people in Taiwan and Hong Kong have shown an association between agranulocytosis induced by antithyroid drugs and the HLA alleles HLA-B*38:02 and HLA-DRB1*08:03. We aimed to identify genetic variants associated with antithyroid drug-induced agranulocytosis in a white European population.

METHODS

We did a GWAS in 234 European adults with any non-chemotherapy drug-induced agranulocytosis (absolute neutrophil count ≤0·5 × 10(9)/L [≤500/μL]) and 5170 population controls. 39 of the 234 patients had agranulocytosis that was induced by antithyroid drugs (thiamazole [methimazole], carbimazole, or propylthiouracil). After imputation and HLA allele prediction, 9 380 034 single nucleotide polymorphisms (SNPs) and 180 HLA alleles were tested for association. The genome-wide significance threshold was p<5 × 10(-8).

FINDINGS

Agranulocytosis induced by non-chemotherapy drugs in general was significantly associated with the HLA region on chromosome 6, with odds ratios (ORs) of 3·24 (95% CI 2·31-4·55, p=1·20 × 10(-11)) for HLA-B*27:05 and 3·57 (2·61-4·90, p=2·32 × 10(-15)) for the top SNP (rs114291795). Drug-specific analysis showed that the association with HLA-B*27:05 was largely driven by cases induced by antithyroid drugs. In a multiple logistic regression model, the OR for HLA-B*27:05 was 7·30 (3·81-13·96) when antithyroid drug-induced agranulocytosis was compared with population controls (p=1·91 × 10(-9)) and 16·91 (3·44-83·17) when compared with a small group of hyperthyroid controls (p=5·04 × 10(-4)). Three SNPs were strongly associated with antithyroid drug-induced agranulocytosis: rs652888 (OR 4·73, 95% CI 3·00-7·44, p=1·92 × 10(-11)) and rs199564443 (17·42, 7·38-41·12, p=7·04 × 10(-11)), which were independent of HLA-B*27:05, and rs1071816 (5·27, 3·06-9·10, p=2·35 × 10(-9)) which was in moderate linkage disequilibrium with HLA-B*27:05. In heterozygous carriers of all three SNPs, the predicted probability of antithyroid drug-induced agranulocytosis was about 30% (OR 753, 95% CI 105-6812). To avoid one case of agranulocytosis, based on the possible risk reduction if all three SNPs are genotyped and carriers are treated or monitored differently from non-carriers, roughly 238 patients would need to be genotyped.

INTERPRETATION

In white European people, antithyroid drug-induced agranulocytosis was associated with HLA-B*27:05 and with other SNPs on chromosome 6. In the future, carriers of these variants could be placed under intensified monitoring or offered alternative treatment for hyperthyroidism.

FUNDING

Swedish Research Council, Swedish Heart and Lung Foundation, Clinical Research Support at Uppsala University, German Federal Institute for Drugs and Medical Devices, Carlos III Spanish Health Institute, European Regional Development Fund, UK National Institute for Health Research, The Selander's Foundation, Thuréus Foundation, European Commission, and Science for Life Laboratory.

[Antithyroid agents related agranulocytosis: Literature review]

The antithyroid agents (carbimazole, methimazole, thiamazole, propylthiouracil and benzylthiouracile) are the drug class that is associated with a high risk of agranulocytosis. Acute and profound (<0.5×10(9)/L) isolated neutropenia occurring in a subject treated with antithyroid agents should be considered as a drug-induced agranulocytosis, until proven otherwise. The clinical spectrum ranges from discovery of acute severe but asymptomatic neutropenia, to isolated fever, localized infections (especially ear, nose and throat, or pulmonary) or septicemia. With an optimal management (discontinuation of antithyroid agents, antibiotics in the presence of fever or a documented infection, or use of hematopoietic growth factor) the current mortality is close to 2%.

Genetic determinants of antithyroid drug-induced agranulocytosis by human leukocyte antigen genotyping and genome-wide association study

Graves' disease is the leading cause of hyperthyroidism affecting 1.0–1.6% of the population. Antithyroid drugs are the treatment cornerstone, but may cause life-threatening agranulocytosis. Here we conduct a two-stage association study on two separate subject sets (in total 42 agranulocytosis cases and 1,208 Graves' disease controls), using direct human leukocyte antigen genotyping and SNP-based genome-wide association study. We demonstrate HLA-B*38:02 (Armitage trend P_combined=6.75 × 10⁻³²) and HLA-DRB1*08:03 (P_combined=1.83 × 10⁻⁹) as independent susceptibility loci. The genome-wide association study identifies the same signals. Estimated odds ratios for these two loci comparing effective allele carriers to non-carriers are 21.48 (95% confidence interval=11.13–41.48) and 6.13 (95% confidence interval=3.28–11.46), respectively. Carrying both HLA-B*38:02 and HLA-DRB1*08:03 increases odds ratio to 48.41 (P_combined=3.32 × 10⁻²¹, 95% confidence interval=21.66–108.22). Our results could be useful for antithyroid-induced agranulocytosis and potentially for agranulocytosis caused by other chemicals.

Graves' disease is the leading cause of hyperthyroidism but treatment options can cause life-threatening complications. Chen et al. conduct two-stage direct HLA genotyping and genome-wide association studies to identify HLA-B*38:02 and HLA-DRB1*08:03 as major pharmacogenetic determinants.

Genetics of Interstitial Lung Disease: Vol de Nuit (Night Flight)

Interstitial lung disease (ILD) is a chronic, progressive fibrotic lung disease with a dismal prognosis. ILD of unknown etiology is referred to as idiopathic interstitial pneumonia (IIP), which is sporadic in the majority of cases. ILD is frequently accompanied by rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), and other autoimmune diseases, and is referred to as collagen vascular disease-associated ILD (CVD-ILD). Susceptibility to ILD is influenced by genetic and environmental factors. Recent advances in radiographic imaging techniques such as high-resolution computed tomography (CT) scanning as well as high-throughput genomic analyses have provided insights into the genetics of ILD. These studies have repeatedly revealed an association between IIP (sporadic and familial) and a single nucleotide polymorphism (SNP) in the promoter region of the mucin 5B (MUC5B). HLA-DRB1*11 alleles have been reported to correlate with ILD in European patients with SSc, whereas in Japanese patients with RA, the HLA-DR2 serological group was identified. The aim of this review is to describe the genetic background of sporadic IIP, CVD-ILD, drug-induced-ILD (DI-ILD), pneumoconiosis, and hypersensitivity pneumonitis. The genetics of ILD is still in progress. However, this information will enhance the understanding of the pathogenesis of ILD and aid the identification of novel therapeutic targets for personalized medicine in future.

Human leukocyte antigen polymorphisms and personalized medicine for rheumatoid arthritis

Human leukocyte antigen (HLA) polymorphisms are the most important genetic risk factors for rheumatoid arthritis (RA), a chronic systemic inflammatory disease of unknown etiology. Certain HLA-DRB1 alleles, known as shared epitope (SE) alleles because they have the same amino-acid sequence at positions 70-74, are associated with susceptibility to RA. A gene dosage effect is present for RA-predisposing SE alleles, and protective alleles show epistasis. An important role of amino-acid polymorphisms at positions 11 and 13 of the HLA-DRβ chain was also reported recently. Rheumatoid factor and anticitrullinated peptide antibodies are present in many RA patients. Similar to extra-articular manifestations, the presence of these autoantibodies is also associated with certain DRB1 alleles. Different frequencies of RA risk alleles in different ethnicities explain the varying prevalence of RA in different populations and suggest genetic heterogeneity of RA with regard to phenotype and population subsets. Some drug-induced hypersensitivity reactions due to disease-modifying antirheumatic drugs are also associated with HLA alleles. Understanding the role of HLA as the most important genetic factor relevant to RA susceptibility may help in determining its pathogenesis and pave the way to personalized medicine.

Selective myelosuppression following yellow phosphorus ingestion

Toxicity from accidental and intentional ingestion of yellow phosphorus, ubiquitously present in fireworks and rodenticides, has recently become more frequent. Gastrointestinal, renal, neurologic, and cardiovascular manifestations are common, with mortality of 23 per cent to 73 per cent. Reports of haematological abnormalities are rare. We report only the second case of severe neutropenia secondary to selective myelosuppression in a 14-year-old girl following intentional ingestion of yellow phosphorus. Leucocyte counts recovered spontaneously without further complications. Our case indicates that, besides hepatic and renal function monitoring, physicians should meticulously monitor blood counts in such cases for early detection of marrow suppression. Further studies are required to elucidate the complex mechanisms and significance of this unusual toxicity of yellow phosphorus.

Phase 2a, randomized, double-blind, placebo-controlled, multicenter, parallel-group study of a H4 R-antagonist (JNJ-39758979) in Japanese adults with moderate atopic dermatitis

This trial was conducted to evaluate the safety and efficacy of the H4 R-antagonist JNJ-39758979 in adult Japanese patients with moderate atopic dermatitis (AD). Eligible patients were randomly assigned to JNJ-39758979 300 mg, 100 mg or placebo once daily for 6 weeks in this phase 2a, double-blind, multicenter, placebo-controlled study. Primary efficacy was assessed via week-6 Eczema Area and Severity Index (EASI) scores. Secondary efficacy assessments included Investigator's Global Assessment (IGA) and patient-reported outcome (PRO) pruritus assessments (Pruritus Categorical Response Scale [PCRS], Pruritus Numeric Rating Scales [PNRS], Pruritus Interference Numeric Rating Scale [PINRS] and Subject's Global Impressions of Change in Pruritus [SGICP]). Eighty-eight of 105 planned patients were randomized before the study was stopped and unblinded for safety reasons. The study did not meet the primary end-point. However, numerical improvements (i.e. decreases) in median EASI were observed with JNJ-39758979 100 mg (-3.7) and 300 mg (-3.0) versus placebo (-1.3) at week 6. Nominally significant improvements across PRO PCRS, PNRS and SGICP assessments were consistently observed, particularly with JNJ-39758979 300 mg. Safety, including adverse events (AE), was comparable between JNJ-39758979 and placebo with the exception of two patients (both receiving JNJ-39758979 300 mg) with serious AE of neutropenia, leading to premature study discontinuation. No deaths were reported. Except for neutropenia, no clinically relevant changes in laboratory values were observed. Although not conclusive, findings suggest H4 R-antagonism may be beneficial for AD, particularly in controlling pruritus. JNJ-39758979 appears to be associated with drug-induced agranulocytosis, likely an off-target effect.

Nonchemotherapy drug-induced neutropenia and agranulocytosis: could medications be the culprit?

Drug-induced agranulocytosis is a severe complication that has been implicated with most classes of medications. Medications such as clozapine, trimethoprim-sulfamethoxazole and methimazole have been more commonly associated with agranulocytosis than other agents. Although the pathogenesis isn't fully elucidated, it appears to be two-fold with a direct toxicity to the myeloid cell line and immune-mediated destruction. Patients may be asymptomatic at the time neutropenia is discovered or may present with more severe complications such as sepsis. In approximately 5% of cases drug-induced agranulocytosis may be fatal. Management of drug-induced agranulocytosis includes the immediate discontinuation of the offending medication, initiation of broad-spectrum antibiotics and consideration of the use of granulocyte colony-stimulating factors in high-risk patients.

Relationship between Leukopenia and Intercellular Adhesion Molecules in Graves' Disease

OBJECTIVE

Changes in soluble intercellular adhesion molecule-1 (sICAM-1) and E-selectin levels as well as leukocyte count were examined in this study to explore the relationship between leukopenia and ICAMs in Graves' disease (GD).

METHODS

Fasting blood samples were obtained from 37 GD patients with normal leukocytes and 32 GD patients with leukopenia. Enzyme-linked immunosorbent assay (ELISA) was performed to determine serum sICAM-1 and E-selectin levels for comparison. The same analyses were repeated for the GD patients with leukopenia after glucocorticoid treatment (15 mg/day to 30 mg/day prednisone).

RESULTS

The ELISA results showed that E-selectin levels were higher in GD patients with leukopenia than those with normal leukocytes (p < 0.05), but these levels decreased after glucocorticoid (prednisone) treatment (p < 0.05). No significant change in sICAM-1 levels was observed (p = 0.12). Correlation analysis showed that leukocyte count and E-selectin were negatively correlated (r = -0.778; p < 0.05).

CONCLUSION

E-selectin may have an important function in GD with leukopenia, and glucocorticoids (prednisone) could decrease E-selectin level, which may be a new therapy target for GD with leukopenia.

HLA-DRB1*08:02 Is Associated with Bucillamine-Induced Proteinuria in Japanese Rheumatoid Arthritis Patients

BACKGROUND

Drug-induced proteinuria can occur in rheumatoid arthritis (RA) patients treated with d-penicillamine, gold salts, or bucillamine (Buc), and represents a drug hypersensitivity reaction. Striking associations of human leukocyte antigen (HLA) alleles with adverse reactions have recently been reported for many drugs.

METHODS

We investigated the association of HLA class II with Buc-induced proteinuria (BI-Pro) in 485 Japanese RA patients treated with Buc, of whom 25 had developed BI-Pro.

RESULTS AND CONCLUSION

This preliminary study showed a highly significant association of DRB1*08:02 with BI-Pro (P = 1.09 × 10⁻⁶, corrected P [Pc] = 1.96 × 10⁻⁵, odds ratio [OR] 25.17, 95% confidence interval [CI] 7.98–79.38). DQB1*04:02 was also significantly associated with increased risk of BI-Pro (P = 2.44 × 10⁻⁵, Pc = 2.69 × 10⁻⁴, OR 10.35, 95%CI 3.99–26.83). These findings provide useful information for promoting personalized medicine for RA.

Characteristics of agranulocytosis as an adverse effect of antithyroid drugs in the second or later course of treatment

BACKGROUND

Agranulocytosis is a serious adverse effect of antithyroid drugs (ATDs) and mainly develops within three months after the start of uninterrupted ATD treatment. Agranulocytosis can also develop for the first time after interruption and subsequent resumption of the same ATD treatment. However, little is known with regard to agranulocytosis that develops after resumption of the same ATD treatment.

OBJECTIVES

We investigated the characteristics of patients who developed agranulocytosis during their second or later course of ATD treatment.

METHODS

A total of 81 patients at our hospital were diagnosed with ATD-induced agranulocytosis. In 14 of the cases (methimazole (MMI), n=10; propylthiouracil (PTU), n=4), the agranulocytosis developed for the first time in the context of the second or later course of treatment with the same ATD; those patients were designated the "resumed group." The 35 patients (MMI, n=28; PTU, n=7) who developed agranulocytosis during their first uninterrupted course of ATD therapy were designated the "first group."

RESULTS

The median total duration of ATD treatment before the diagnosis of agranulocytosis was 559 days (range 86-1775 days), and the median interval between the final day of the previous course and the first day of the course in which agranulocytosis was diagnosed was 916.5 days (range 153-8110 days). There were no cases in which agranulocytosis developed when treatment with the same ATD was resumed after discontinuation for less than five months. The difference between the start of ATD treatment in the course in which agranulocytosis was diagnosed and the time interval at which agranulocytosis was diagnosed was similar when comparing the first group and the resumed group (39 (20-98) days in the first group vs. 32.5 (21-95) days in the resumed group; n.s.). There were no significant differences between the groups in terms of granulocyte count at the time agranulocytosis was diagnosed, mortality rate, or the interval between the diagnosis of agranulocytosis and recovery.

CONCLUSIONS

When ATD treatment is resumed, patient follow-up is essential in order to monitor for the development of agranulocytosis.

Successful treatment of methimazole-induced severe aplastic anemia by granulocyte colony-stimulating factor, methylprednisolone, and cyclosporin

A 52-year-old Japanese woman was examined because of general malaise, weight loss and a lump in her left breast. She was diagnosed with cancer of the left breast and Graves' disease, and was administered methimazole (MMI). A left mastectomy was performed for the breast cancer. She presented with a high fever and peripheral blood examination revealed a severe pancytopenia. She was diagnosed with severe aplastic anemia, and administered G-CSF, however, the treatment was unsuccessful. Thus, oral methyprednisolone and cyclosporin were added. There was a remarkable improvement in the peripheral blood count.

Pharmacologic Management of Feline Hyperthyroidism

Radioiodine is considered the treatment of choice for hyperthyroidism, but in some situations, methimazole therapy is preferred, such as in cats with preexisting renal insufficiency. Unfavorable outcomes from methimazole are usually attributable to side effects, such as gastrointestinal upset, facial excoriation, thrombocytopenia, neutropenia, or liver enzyme elevations. Because restoration of euthyroidism can lead to a drop in glomerular filtration rate, all cats treated with methimazole should be monitored with blood urea nitrogen and creatinine levels in addition to serum thyroxine (T(4)) and a complete blood cell count. Transdermal methimazole is associated with fewer gastrointestinal side effects and can be used in cats with simple vomiting or inappetence from oral methimazole. Hypertension may not resolve immediately when serum T(4) is normalized, and moderate to severe hypertension should be treated concurrently with atenolol, amlodipine, or an angiotensin-converting enzyme inhibitor.

The relation of initial methimazole dose to the incidence of methimazole-induced agranulocytosis in patients with Graves' disease

The relation between the incidence of methimazole (methylmercaptoimidazole; MMI)-induced agranulocytosis and initial MMI dose was evaluated in a group of 514 patients with Graves' disease who were treated between 1995 and 2005. One hundred and forty-six (28.40%) patients had received an initial dose of 30 mg MMI and 277 (53.89%) patients had been treated with 15 mg MMI. Nine patients (1.75%) developed agranulocytosis due to MMI treatment. Six (4.11%) of 146 patients who received an initial dose of 30 mg MMI, two (4.54%) of 44 patients given an initial dose of 20 mg MMI, and one (0.36%) of 277 patients given an initial dose of 15 mg MMI developed agranulocytosis. There was a statistically significant difference in agranulocytosis incidence between patients receiving an initial dose of 30 mg MMI and those who received an initial dose of 15 mg. Although 8 (4.10%) of 195 patients in the high-dose group (20 mg or higher) developed agranulocytosis, only 1 (0.31%) of 319 patients in the low-dose group (15 mg or lower) did. In conclusion, the incidence of agranulocytosis with low-dose MMI therapy was ten times lower than that of the high-dose regimen.

Medical management of hyperthyroidism

Radioiodine is considered the treatment of choice for hyperthyroidism, but in some situations, methimazole therapy is preferred, such as in cats with pre-existing renal insufficiency. Methimazole blocks thyroid hormone synthesis, and controls hyperthyroidism in more than 90% of cats that tolerate the drug. Unfavorable outcomes are usually due to side effects such as gastrointestinal (GI) upset, facial excoriation, thrombocytopenia, neutropenia, or liver enzyme elevations; warfarin-like coagulopathy or myasthenia gravis have been reported but are rare. Because restoration of euthyroidism can lead to a drop in glomerular filtration rate, all cats treated with methimazole should be monitored with BUN and creatinine, in addition to serum T4, complete blood count, and liver enzymes. Transdermal methimazole is associated with fewer GI side effects, and can be used in cats with simple vomiting or inappetance from oral methimazole. Hypertension may not resolve immediately when serum T4 is normalized, and moderate to severe hypertension should be treated concurrently with-atenolol, amlodipine, or an ACE inhibitor. Alternatives to methimazole include carbimazole, propylthiouracil, or iodinated contrast agents.

[Evaluation of the medical treatment of Graves' disease (GD)]

The treatment of Graves' disease (GD) with antithyroid drugs (ATD) leads to remission of the disease in approximately half of patients treated for at least six months, and the overall relapse rate is high, ranging from 60% to 80%. The presence of prognostic features for achieving a remission after medical treatment is a matter of discussion in the literature. The aim of this study is to evaluate the effect of different ATD regimens available in Brazil (propylthiouracil--PTU and methimazole--MMI) on remission and relapse rates of GD, as well as to determine possible predictors of remission and relapse of the disease and the side effects profile. We reviewed the records from all patients submitted to medical treatment of GD (and with no report of prior treatment of the disease) for at least six months and followed for at least 12 months after the drug withdrawal at Hospital Universitário Clementino Fraga Filho (HUCFF), between October 1978 and August 2003. We identified 127 patients, with the age ranging from 18 to 88 years (mean 39.3 +/- 12.8). Remission was observed in 58 patients (45.7%) and relapse occurred in 31 (53.4%), at a mean period of 14.5 +/- 16.1 months. We verified that the duration of symptoms before the beginning of medical treatment, age and gender did not influence the rate of remission and the relapse risk, whereas the presence of large goiter size (> 40 grams), Graves' ophthalmopathy and use of high daily doses of ATD (> or = 600 mg of propylthiouracil/60 mg of methimazole MMI) were associated with a decreased remission rate. Moreover, patients who presented a TSH measurement < 0.4 microIU/mL between 4 to 5 weeks after the drug withdrawal showed an increased relapse cumulative probability. In conclusion, our results confirms that lasting remission rate of GD treated with ATD is relatively low. We concluded that the combination of goiter size > 40 g, ophthalmopathy, and use of daily doses of PTU > or = 600 mg or MMI > or = 60 mg was vigorously related to lack of remission of GD. Furthermore, TSH measurement between 4 to 5 weeks after the drug withdrawal seems to be a useful tool to determine the remission chance and the relapse risk of the disease.

Retrospective analysis of 18 cases of antithyroid drug (ATD)-induced agranulocytosis

In this study, we retrospectively analyzed 18 patients in whom antithyroid drug (ATD)-induced agranulocytosis developed during treatment of Graves' disease. All patients were more than 20 years of age, and we saw no correlation between age and the development of agranulocytosis. In 17 of 18 patients, ATD-induced agranulocytosis developed within 2 to 12 weeks of starting ATD treatment. Development of agranulocytosis was related to the dose of ATD. In some patients, agranulocytosis developed abruptly, and even weekly routine WBC and granulocyte counts failed to predict all case occurrences. Fever and sore throat were the earliest symptoms of agranulocytosis; patients who developed either of these symptoms were closely monitored immediately with WBC and granulocyte count examinations. In this series of patients, treatment with granulocyte-macrophage colony stimulating factor (GM-CSF) increased the granulocyte counts, whereas the effectiveness of glucocorticoid treatment was not confirmed.

Increased frequency of HLA-DR2 in patients with paroxysmal nocturnal hemoglobinuria and the PNH/aplastic anemia syndrome

Many autoimmune diseases are associated with HLA alleles, and such a relationship also has been reported for aplastic anemia (AA). AA and paroxysmal nocturnal hemoglobinuria (PNH) are related clinically, and glycophosphoinositol (GPI)-anchored protein (AP)-deficient cells can be found in many patients with AA. The hypothesis was considered that expansion of a PNH clone may be a marker of immune-mediated disease and its association with HLA alleles was examined. The study involved patients with a primary diagnosis of AA, patients with myelodysplastic syndrome (MDS), and patients with primary PNH. Tests of proportions were used to compare allelic frequencies. For patients with a PNH clone (defined by the presence of GPI-AP-deficient granulocytes), regardless of clinical manifestations, there was a higher than normal incidence of HLA-DR2 (58% versus 28%; z = 4.05). The increased presence of HLA-DR2 was found in all frankly hemolytic PNH and in PNH associated with bone marrow failure (AA/PNH and MDS/PNH). HLA-DR2 was more frequent in AA/PNH (56%) than in AA without a PNH clone (37%; z = 3.36). Analysis of a second cohort of patients with bone marrow failure treated with immunosuppression showed that HLA-DR2 was associated with a hematologic response (50% of responders versus 34% of nonresponders; z = 2.69). Both the presence of HLA-DR2 and the PNH clone were independent predictors of response but the size of PNH clone did not correlate with improvement in blood count. The results suggest that clonal expansion of GPI-AP-deficient cells is linked to HLA and likely related to an immune mechanism.

Acute pancreatitis and parotitis induced by methimazole in a patient with Graves' disease

A wide variety of adverse effects of methimazole (MMI) have been reported. Here we report a new MMI-induced disorder, acute pancreatitis and parotitis. Three weeks after a woman started MMI treatment for Graves' disease, she developed a high fever, painful parotid swelling and dull pain in the upper abdomen with elevation of the serum levels of salivary and pancreatic enzymes. These abnormalities disappeared soon after the withdrawal of MMI. However, the same abnormalities were rapidly provoked when MMI was reintroduced. Marked increases in the leucocyte count and CRP were also observed during these episodes. The possible mechanisms of MMI-induced pancreatitis/parotitis are discussed.

Methimazole-induced aplastic anemia in third exposure: successful treatment with recombinant human granulocyte colony-stimulating factor

The major adverse reactions of antithyroid drugs are hematologic; aplastic anemia (AA) is one of the rarest and most severe complications. Use of recombinant human hemopoietic colony-stimulating factor was reported to be of benefit in patients who developed agranulocytosis, although there is still some doubt regarding the efficacy in AA. We present a case of a 58-year-old female patient with Graves' disease who developed AA in the third exposure to methimazole (MMI). The withdrawal of MMI and early treatment with 5 microg/kg per day recombinant human granulocyte colony-stimulating factor (G-CSF) for 9 days, allowed a favorable recovery of peripheral blood cell count. We conclude that the use of hemopoietic colony stimulating factors might be a suitable means to achieve the correction of severe thionamide-induced hematologic adverse reactions.