Unveiling the mechanisms of trichloroethylene hypersensitivity syndrome: Exploring the role of connexin 43 gap junctions in severe skin damage

Trichloroethylene (TCE), extensively used as an organic solvent in various industrial applications, has been identified as a causative factor in inducing hypersensitivity syndrome (THS). Currently, there is no specific treatment for THS, and most patients experience serious adverse outcomes due to extensive skin damage leading to severe infection. However, the pathogenesis of THS-associated skin damage remains unclear. This study aims to elucidate the mechanism underlying skin damage from the perspective of intercellular communication and gap junctions in THS. Our results verified that hyperactivation of connexin43 gap junctions, caused by the aberrantly elevated expression of connexin43, triggers a bystander effect that promotes apoptosis and inflammation in THS via the TNF-TNFRSF1B and mitochondria-associated pathways. Additionally, we identified the gap junction inhibitor Carbenoxolone disodium (CBX) as a promising agent for the treatment of skin damage in THS. CBX protects against inflammatory cell infiltration in the skin and decreases immune cell imbalance in the peripheral blood of THS mice. Furthermore, CBX reduces connexin43 expression, apoptosis and inflammation in THS mice. The study reveals new insights into the mechanisms underlying TCE-induced skin damage, offering a potential treatment strategy for the development of effective therapies targeting severe dermatitis induced by chemical exposure.

Increased serum anti-CYP2E1 IgG autoantibody levels may be involved in the pathogenesis of occupational trichloroethylene hypersensitivity syndrome: a case-control study

Occupational exposure to trichloroethylene (TCE) causes a systemic skin disorder with hepatitis known as TCE hypersensitivity syndrome (TCE-HS). Human Leukocyte Antigen (HLA)-B*13:01 is its susceptibility factor; however, the immunological pathogenesis of TCE-HS remains unknown. We herein examined the hypothesis that autoantibodies to CYP2E1 are primarily involved in TCE-HS. A case–control study of 80 TCE-HS patients, 186 TCE-tolerant controls (TCE-TC), and 71 TCE-nonexposed controls (TCE-nonEC) was conducted to measure their serum anti-CYP2E1 antibody (IgG) levels. The effects of TCE exposure indices, such as 8-h time-weighted-average (TWA) airborne concentrations, urinary metabolite concentrations, and TCE usage duration; sex; smoking and drinking habits; and alanine aminotransferase (ALT) levels on the antibody levels were also analyzed in the two control groups. There were significant differences in anti-CYP2E1 antibody levels among the three groups: TCE-TC > TCE-HS patients > TCE-nonEC. Antibody levels were not different between HLA-B*13:01 carriers and noncarriers in TCE-HS patients and TCE-TC. The serum CYP2E1 measurement suggested increased immunocomplex levels only in patients with TCE-HS. Multiple regression analysis for the two control groups showed that the antibody levels were significantly higher by the TCE exposure. Women had higher antibody levels than men; however, smoking, drinking, and ALT levels did not affect the anti-CYP2E1 antibody levels. Anti-CYP2E1 antibodies were elevated at concentrations lower than the TWA concentration of 2.5 ppm for TCE exposure. Since HLA-B*13:01 polymorphism was not involved in the autoantibody levels, the possible mechanism underlying the pathogenesis of TCE-HS is that TCE exposure induces anti-CYP2E1 autoantibody production, and HLA-B*13:01 is involved in the development of TCE-HS.

Antiepileptic Hypersensitivity Syndrome to Phenobarbital: A Case Report

Phenobarbital is still one of the most commonly used medical treatments for different types of seizures. It has numerous different side-effects. Antiepileptic hypersensitivity syndrome (AHS) is a rare and potentially life-threatening adverse reaction to aromatic anticonvulsants such as phenobarbital. Its characteristic features are fever, rash, and lymphadenopathy with different severity of hematologic abnormalities. This case report presents a 26-month-old girl that developed fever, disseminated maculopapular rash, petechiae and thrombocytopenia two weeks after the initiation of phenobarbital prescribed for febrile seizure prophylaxis. The patient was admitted in our center with the impression of hypersensitivity syndrome, so phenobarbital was discontinued and her treatment was resumed with methylprednisolone and intravenous immunoglobulin. After a few days, all symptoms improved and the platelet count was normalized. Thrombocytopenia is a rare complication of hypersensitivity syndrome to phenobarbital in children. Paying attention to this point can prevent the life-threatening adverse effects of this highly consumed medicine.

Joint association of carrying HLA-B*13:01 gene and human herpesvirus-6 with occupational trichloroethylene hypersensitivity syndrome

PURPOSE

Occupational trichloroethylene hypersensitivity syndrome (OTHS) clinically manifests as generalized severe rash resembling drug-induced hypersensitivity syndrome (DIHS) and afflicts predominantly HLA-B*13:01 gene carriers after their exposure to trichloroethylene. Meanwhile, OTHS may also be associated with human herpesvirus such as herpesvirus-6 (HHV6) and cytomegalovirus (HCMV) reported to participate in the pathology of DIHS. This study explored the association of carrying HHV6 and HCMV, and the joint association of carrying HLA-B*13:01 and HHV6 and HCMV with OTHS.

METHODS

We recruited 30 OTHS patients and 40 trichloroethylene-exposed healthy workers as cases and controls, respectively. HLA-B*13:01 was genotyped and HHV6 and HCMV DNA were detected in the DNA extracted from whole-blood sample of each participant with PCR techniques. Positive rates of HLA-B*13:01 gene and HHV6 and HCMV DNA and their association with OTHS were then analyzed.

RESULTS

The OTHS cases showed significantly higher positive rates of HLA-B*13:01 gene and HHV6 DNA, but not HCMV DNA, than the controls (83.3% vs. 25.0% and 56.7% vs. 10.0%, respectively, both P < 0.001). Positive rate of HHV6 DNA was significantly higher in HLA-B*13:01 carriers than in non-carriers in the cases (68.0% vs. 0, P = 0.005), but not in the controls. Carrying HLA-B*13:01 and HHV6 had an interactive effect on OTHS (OR = 91.80, P < 0.001).

CONCLUSIONS

Carrying HLA-B*13:01 and HHV6 may be associated with OTHS; furthermore, carrying HLA-B*13:01 and HHV6 may be jointly associated with OTHS.

Exposure reconstruction of trichloroethylene among patients with occupational trichloroethylene hypersensitivity syndrome

Occupational trichloroethylene (TCE) exposure can induce life-threatening generalized dermatitis accompanied by hepatitis: TCE hypersensitivity syndrome (HS). Since the patients' exposure levels have not been fully clarified, this study estimated end-of-shift urinary concentrations of trichloroacetic acid (TCA) and their lower limit below which the disease occurrence was rare. TCA concentration was measured in 78 TCE HS patients whose urine was collected at admission between 2nd and 14th d after their last shift. Then a linear regression model was used to calculate the mean TCA concentration with 95% confidence interval (95% CI) and 95% prediction interval (95% PI) in the end-of-shift urine. The estimated mean concentration was 83 (95% CI, 49-140) mg/l with 95% PI 9.6-720 mg/l. TCA concentrations were also measured in the end-of-shift urine of 38 healthy workers involved in the same job as were the patients. The geometric mean and its 95% CI were 127 mg/l and 16-984 mg/l, respectively. The exposure levels in HS patients might have thus overlapped with those in workers without HS. Accordingly, it was suggested that HS occurred in the environment where the workers were exposed to the TCE concentration corresponding to the urinary TCA concentration as low as 10 mg/l.

[DRESS syndrome secondary to antituberculosis drugs: about a case]

Drug hypersensitivity syndrome or Drug Rash with Eosinophilia and Systemic Symptoms or DRESS syndrome is a severe and potentially life-threatening toxidermia. It should be suspected in patients developing cutaneous reaction following drug intake. We report the case of a 45-year old patient treated for pulmonary tuberculosis (TPM+) who developed DRESS syndrom induced by antibacillaries.

Alectinib-Induced Erythema Multiforme and Successful Rechallenge with Alectinib in a Patient with Anaplastic Lymphoma Kinase-Rearranged Lung Cancer

Background

Alectinib is an oral drug developed for the treatment of patients with fusion gene encoding echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK)-rearranged non-small cell lung cancer (NSCLC). Here, we present the case of a patient treated with alectinib who developed a hypersensitivity reaction with successful rechallenge treatment.

Case Presentation

A 39-year-old woman who was a passive smoker was referred to Osaka City University Hospital for the evaluation of a skin event caused by treatment for NSCLC with the fusion gene EML4-ALK. The skin reaction was observed on the anterior chest, upper arms, and ear auricles on day 11 of treatment with oral alectinib. The skin event presented as widely distributed erythematous macules that were confluent, indicating a severe and life-threatening form. The skin lesions started to resolve after the initiation of treatment with 40 mg prednisolone. After regrowth of the tumor, she received a rechallenge program for alectinib for 2 weeks; thereafter, alectinib treatment was successfully reinitiated.

Conclusion

To the best of our knowledge, we present the first case in which alectinib, which binds to the adenosine triphosphate site of EML4-ALK, induced erythema multiforme. Moreover, successful readministration of alectinib through our rechallenge program has not been reported so far.

Fever, rash, and systemic symptoms: understanding the role of virus and HLA in severe cutaneous drug allergy

Drug hypersensitivity syndromes such as abacavir hypersensitivity and the severe cutaneous adverse drug reactions have been associated with significant short- and long-term morbidity and mortality. More recently, these immunologically mediated and previously unpredictable diseases have been shown to be associated with primarily class I but also class II HLA alleles. The case of the association of HLA-B*57:01 and abacavir hypersensitivity has created a translational roadmap for how this knowledge can be used in the clinic to prevent severe reactions. Although many hurdles exist to the widespread translation of such HLA screening approaches, our understanding of how drugs interact with the major histocompatibility complex has contributed to the discovery of new models that have provided considerable insights into the immunopathogenesis of severe cutaneous adverse drug reactions and other T-cell-mediated drug hypersensitivity syndromes. Future translation of this knowledge will facilitate the development of preclinical toxicity screening to significantly improve efficacy and safety of drug development and design.