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

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.

Clinical characteristics of antithyroid drug-induced aplastic anemia cases over the past 30 years

OBJECTIVE

The authors aimed to investigate the clinical characteristics of antithyroid drug-induced aplastic anemia cases over the past 30 years.

METHODS

The data of patients with antithyroid drug-induced aplastic anemia were retrieved from PubMed and Wanfang Medical Network databases from 1992 to August 2022. The clinical characteristics, such as age distribution, gender tendency, common symptoms, blood cell count, bone marrow features, treatment strategy, and prognosis, were analyzed.

RESULTS

A total of 17 cases (male:female = 1:16) had been retrieved. Patients' age ranged from 16 to 74 years (median 50 years). Among them, 82.3% (14/17) of the patients were administered methimazole (MMI), and 78.6% of them had MMI ≥30 mg/day. In addition, 88.2% (15/17) of the patients had sore throat and fever, and 47.1% (8/17) of the patients had hemorrhagic symptoms. Aplastic anemia occurred within 6 months after initiation of the antithyroid therapy in 94.1% of the patients. Agranulocytosis (94.1%) was the most common and earliest blood cell change, and 47.1% of the patients experienced progressive platelet decline during the treatment process. The treatments include timely withdrawal of antithyroid drugs, broad-spectrum antibiotics, granulocyte colony-stimulating factor (G-CSF)/granulocyte-macrophage colony-stimulating factor (GM-CSF), glucocorticoids and other immunosuppressive agents, and supportive treatments such as erythrocyte transfusion and platelet transfusion. Moreover, 70.6% of the patients had complete or near-complete remission within 8 days to 6 weeks.

CONCLUSION

Aplastic anemia is a rare and serious adverse reaction of antithyroid drugs, which is more common in women. It usually occurs during early treatment with high-dose antithyroid drugs. Most patients have a good prognosis after timely drug ceasing and appropriate treatment.

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.

Drug-induced hypersensitivity syndrome induced by propylthiouracil: case report and literature review

Background

Drug-induced hypersensitivity syndrome (DIHS) is a rare, potentially life-threatening systemic drug reaction. Antithyroid drugs (ATDs) causing DIHS have seldom been reported before.

Case presentation

We present a case of propylthiouracil (PTU)-induced DIHS, which included fever, skin rash, lymphadenopathy, hepatosplenomegaly, serious liver and kidney dysfunction, peripheral blood eosinophilia, and atypical lymphocytosis. Following supportive therapy, intravenous immunoglobulin (IVIG), and systemic corticosteroid, the patient experienced a resolution of fever and rash combined with progressive normalization of hematological index and organ function. These clinical features, and the skin lesion biopsy confirmed DIHS diagnosis.

Conclusions

To our knowledge, this is the second reported case of PTU-induced DIHS worldwide and the first human leukocyte antigen (HLA) typing of PTU-induced DIHS. Clinicians should cautiously distinguish hyperthyroidism etiology and identify the indication of ATDs. Timely recognition and formal DIHS treatment are required in patients with ATDs.

Drug-Induced Hypersensitivity Syndrome (DIHS)/Drug Reaction With Eosinophilia and Systemic Symptoms (DRESS): Clinical Features and Pathogenesis

Drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DIHS/DRESS) is one example of a severe delayed T-cell-mediated adverse drug reaction. DIHS/DRESS presents with fever, widespread rash and facial edema, organ involvement, and hematological abnormalities, including eosinophilia and atypical lymphocytosis. DIHS/DRESS is associated with relapse 2 to 4 weeks after acute symptoms, often coinciding with reactivation of prevalent chronic persistent human herpesviruses such as human herpesvirus 6, EBV, and cytomegalovirus. The mortality of DIHS/DRESS is up to 10% and often related to unrecognized myocarditis and cytomegalovirus complications, with longer-term consequences that contribute to morbidity including autoimmune diseases such as thyroiditis. It is essential that all potential drug causes, including all new drugs introduced within the 8 weeks preceding onset of DIHS/DRESS symptoms, are identified. All potential drug culprits, as well as drugs that are closely related structurally to the culprit drug, should be avoided in the future. Systemic corticosteroids have remained the mainstay for the treatment of DIHS/DRESS with internal organ involvement. Steroid-sparing agents, such as cyclosporine, mycophenolate mofetil, and monthly intravenous immune globulin, have been successfully used for treatment, and careful follow-up for cytomegalovirus reactivation is recommended. Strong associations between HLA class I alleles and DIHS/DRESS predisposition include HLA-B∗13:01 and dapsone, HLA-B∗58:01 and allopurinol, and HLA-B∗32:01 and vancomycin. These have opened a pathway for prevention, risk stratification, and earlier diagnosis. Single-cell sequencing and other studies of immunopathogenesis promise to identify targeted treatment approaches.

Human Leukocyte Antigen (HLA) Testing in Pharmacogenomics

The genetic region on the short arm of chromosome 6 where the human leukocyte antigen (HLA) genes are located is the major histocompatibility complex. The genes in this region are highly polymorphic, and some loci have a high degree of homology with other genes and pseudogenes. Histocompatibility testing has traditionally been performed in the setting of transplantation and involves determining which specific alleles are present. Several HLA alleles have been associated with disease risk or increased risk of adverse drug reaction (ADR) when treated with certain medications. Testing for these applications differs from traditional histocompatibility in that the desired result is simply presence or absence of the allele of interest, rather than determining which allele is present. At present, the majority of HLA typing is done by molecular methods using commercially available kits. A subset of pharmacogenomics laboratories has developed their own methods, and in some cases, query single nucleotide variants associated with certain HLA alleles rather than directly testing for the allele. In this chapter, a brief introduction to the HLA system is provided, followed by an overview of a variety of testing technologies including those specifically used in pharmacogenomics, and the chapter concludes with details regarding specific HLA alleles associated with ADR.

A Review of β-Lactam-Associated Neutropenia and Implications for Cross-reactivity

OBJECTIVE

To review the incidence, management, and current understanding of the pathophysiology of β-lactam-induced neutropenia and to critically evaluate the practicality and safety of direct substitution to an alternative β-lactam in the setting of this reaction.

DATA SOURCES

A literature analysis using the PubMed and Ovid search engines (July 1968 to October 2020) was performed using the search terms neutropenia, leukopenia, β-lactam, nonchemotherapy, agranulocytosis, and G-CSF (granulocyte colony-stimulating factor).

STUDY SELECTION AND DATA EXTRACTION

The included English-language studies evaluated the incidence, mechanism, and/or management of β-lactam-induced neutropenia in pediatric or adult patients.

DATA SYNTHESIS

Drug-induced neutropenia is a well-documented adverse reaction of β-lactam antibiotics, with an incidence of approximately 10% following at least 2 weeks of intravenous therapy. However, multiple gaps in knowledge remain in the mechanism of pathophysiology and optimal management of this reaction. Both direct toxic and immune-mediated mechanisms have been implicated. Although the cornerstone of management includes cessation of the offending agent, controversy exists on the appropriateness of direct substitution or future use of an alternative β-lactam.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Given the frequency of use and superiority of β-lactams over alternative therapy for several infectious disease states, practical recommendations are needed on the management and safe use of β-lactams following β-lactam-induced neutropenia.

CONCLUSION

Future use of β-lactams with differing R1 side chains, particularly those from a separate class, should not be deemed contraindicated following β-lactam-induced neutropenia and may be considered when indicated, with close laboratory monitoring.

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.

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.