HLA analysis of immune checkpoint inhibitor-induced and idiopathic isolated ACTH deficiency

HLA investigation in ICI-induced T1D and isolated ACTH deficiency including meta-analysis

OBJECTIVE

Widespread use of immune checkpoint inhibitors (ICIs) in cancer treatment has led to an increase in the number of reported cases of immunotherapy-related endocrinopathies. This study aimed to analyze and compare human leukocyte antigen (HLA) signatures associated with ICI-induced type 1 diabetes (ICI-T1D) and isolated adrenocorticotropic hormone deficiency (ICI-IAD) in patients with both conditions.

METHODS

HLA signatures were examined for their frequencies of occurrence in 22 patients with ICI-T1D without concurrent IAD, including 16 patients from nationwide reports (ICI-T1D group) and 14 patients with ICI-IAD without concurrent T1D (ICI-IAD group). The HLA signatures were also compared for their respective frequencies in 11 patients with ICI-T1D and ICI-IAD, including eight from nationwide reports (ICI-T1D/IAD group).

RESULTS

In the ICI-T1D group, HLA-DRB1*09:01-DQB1*03:03 and DQA1*03:02, which are in linkage disequilibrium with DRB1*09:01-DQB1*03:03 and DRB1*13:02-DQB1*06:04, were susceptible to ICI-T1D, whereas DRB1*15:02-DQB1*06:01 was protective against ICI-T1D. In the ICI-IAD group, DPB1*09:01, C*12:02-B*52:01, and DRB1*15:02-DRB1*06:01, which are in strong linkage disequilibrium, were associated with susceptibility to ICI-IAD. Moreover, DRB1*15:02-DRB1*06:01 was not detected in the ICI-T1D/IAD group.

CONCLUSIONS

This study revealed specific HLA signatures associated with ICI-T1D and ICI-IAD. Moreover, HLA-DRB1*15:02-DRB1*06:01, an ICI-IAD-susceptible HLA haplotype, coincides with the ICI-T1D-protective HLA haplotype, suggesting that the presence of DRB1*15:02-DRB1*06:01 may protect against the co-occurrence of T1D in patients with ICI-IAD.

The early-stage clinical course of anti-pituitary-specific transcription factor-1 hypophysitis diagnosed post-immune checkpoint inhibitor treatment: A case with review of literature

Anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis, a paraneoplastic syndrome resulting from an autoimmune response against PIT-1, typically manifests with undetectable levels of growth hormone (GH) and prolactin (PRL), and significantly low levels of serum thyroid-stimulating hormone (TSH) at diagnosis. These hormonal levels are highly specific to this disease and serve as key diagnostic indicators. Herein, we present a detailed clinical course of a 69-year-old male with a history of gastric cancer and lymph node metastases who developed anti-PIT-1 hypophysitis after the initiation of immune checkpoint inhibitor (ICI) therapy, specifically nivolumab, oxaliplatin, and capecitabine. The patient was referred to our department owing to decreased TSH, free triiodothyronine (T3), and free thyroxine (T4) levels after two doses of nivolumab. Initially suspected as central hypothyroidism due to ICI-related hypophysitis, further assessment confirmed the diagnosis of anti-PIT-1 hypophysitis. Notably, GH, PRL, and TSH levels markedly declined, leading to complete deficiencies 2 months after the first nivolumab dose-a pattern consistent with that of previous cases of anti-PIT-1 hypophysitis. Therefore, this report not only presents an atypical subset of ICI-related hypophysitis but also delineates the process of hormone impairment leading to complete deficiencies in anti-PIT-1 hypophysitis. This case highlights the importance of vigilant monitoring for endocrine issues in patients undergoing ICI therapy, given the escalating incidence of immune-related adverse events associated with the extensive use of ICI therapy for various cancers.

Idiopathic isolated adrenocorticotropic hormone deficiency: a systematic review of a heterogeneous and underreported disease

Isolated adrenocorticotropic hormone deficiency (IAD) is considered to be a rare disease. Due to the nonspecific clinical presentation, precise data on the prevalence and incidence are lacking. In this systematic review, we aimed to analyse the clinical characteristics, association with autoimmune diseases, and management of acquired idiopathic IAD cases. A structured search was conducted after developing a search strategy combining terms for acquired (idiopathic) IAD. Articles describing an adult case with a diagnosis of ACTH deficiency using dynamic testing, no deficiency of other pituitary axes, and MRI of the brain/pituitary protocolled as normal, were included. Exclusion criteria were cases describing congenital IAD, cases with another aetiology for IAD, and articles where full text was not available. In total 42 articles were included, consisting of 85 cases of acquired idiopathic IAD. Distribution by sex was approximately equal (F:M; 47:38). Lethargy was the most common presenting symptom (38%), followed by weight loss (25%), anorexia (22%), and myalgia/arthralgia (12%). Eight cases (9.5%) presented with an Addison crisis. 31% of cases had an autoimmune disease at diagnosis of which Hashimoto hypothyroidism was the most frequent. Data about follow-up was scarce; dynamic testing was repeated in 4 cases of which 2 showed recovery of the adrenal axis. We report the largest case series of acquired idiopathic IAD to date. Our systematic review highlights the lack of a clear definition and diagnostic work-up. Based on the findings in this review a proposition is made for a flowchart to diagnose acquired idiopathic IAD.

Immune checkpoint inhibitor-induced isolated adrenocorticotropic hormone deficiency: a systematic review

Background

Immune checkpoint inhibitor-induced isolated adrenocorticotropic hormone deficiency (IAD) is a rare but potentially fatal disease.

Methods

We comprehensively searched the PubMed database and made a systematic review of immune checkpoint inhibitor-induced isolated adrenocorticotropic hormone deficiency. If the status of other anterior pituitary hormones was not mentioned, the case was excluded.

Results

We identified 123 cases diagnosed as immune checkpoint inhibitor-induced IAD, consisting of 44 female and 79 male patients. The average age of these patients was 64.3 ± 12.6 years old, and 67.5% were 60 years old or above. The majority (78.9%) of these patients received anti-programmed cell death protein-1 (anti-PD-1) antibodies or anti-programmed cell death ligand 1 (anti-PD-L1) antibodies or both, and 19.5% received combined therapy, sequential therapy, or both. A total of 26 patients received anti-cytotoxic T lymphocyte antigen 4 antibodies (anti-CTLA-4). The median ICI treatment cycle before the diagnosis of adrenal insufficiency was 8 (6, 12), and the median ICI treatment duration before the diagnosis of adrenal insufficiency was 6 (4, 8) months. Eleven cases developed IAD 1 to 11 months after discontinuation of ICIs. Fatigue and appetite loss were the most common symptoms, and surprisingly, there were two asymptomatic cases of IAD. Most patients (88 cases) had normal pituitary magnetic resonance imaging, only 14 cases reported mild atrophy or swelling pituitary gland, and 21 cases reported no imaging results. Most diagnoses were made by basal hormone levels, and pituitary stimulation tests were performed in only a part of the cases. No cases had been reported of discontinuation of ICI use due to IAD nor had there been any deaths due to IAD.

Conclusion

IAD was predominant in elderly male patients mainly receiving anti-PD-1 or anti-PD-L1 antibodies. It was sometimes difficult to recognize IAD at first glance since non-specific symptoms were common and asymptomatic cases of IAD were also reported. Although IAD can be deadly, it usually does not affect the continued use of ICIs.

Review - The impact of pharmacogenetics on the outcome of immune checkpoint inhibitors

The development of immune checkpoint inhibitors (ICIs) has a tremendous effect on the treatment options for multiple types of cancer. Nonetheless, there is a large interpatient variability in response, survival, and the development of immune-related adverse events (irAEs). Pharmacogenetics is the general term for germline genetic variations, which may cause the observed interindividual differences in response or toxicity to treatment. These genetic variations can either be single-nucleotide polymorphisms (SNPs) or structural variants, such as gene deletions, amplifications or rearrangements. For ICIs, pharmacogenetic variation in the human leukocyte antigen molecules has also been studied with regard to treatment outcome. This review presents a summary of the literature regarding the pharmacogenetics of ICI treatment, discusses the most important known genetic variations and offers recommendations on the application of pharmacogenetics for ICI treatment.

Paraneoplastic isolated adrenocorticotropic hormone deficiency revealed after immune checkpoint inhibitors therapy: new insights into anti-corticotroph antibody

Introduction

A recently discovered facet of paraneoplastic adrenocorticotropic hormone (ACTH) deficiency exists in two forms: a paraneoplastic spontaneous isolated ACTH deficiency (IAD) and an immune checkpoint inhibitor (ICI)-related hypophysitis. Autoantibodies against corticotrophs, such as circulating anti-proopiomelanocortin (POMC) antibodies are considered disease markers. However, the number of identified cases was limited, implying that the characteristics of these autoantibodies are not fully understood.

Methods

We investigate circulating autoimmune autoantibodies in detail through a novel case of IAD that developed as a paraneoplastic autoimmune ACTH deficiency.

Results

The patient developed IAD after 25 weeks of ICI therapy for metastasis of large-cell neuroendocrine carcinoma at 69 years of age. Ectopic ACTH expression and infiltration of CD3+, CD4+, CD8+, and CD20+ lymphocytes were observed in the tumor tissues and circulating anti-POMC antibodies were detected specifically in the patient's serum. Moreover, detailed analyses of immunofluorescence staining using patient serum revealed that the recognition site of the autoantibody was ACTH25-39, which had not been identified in previous cases of paraneoplastic autoimmune ACTH deficiency.

Conclusion

This case involved a combination of paraneoplastic spontaneously acquired IAD and ICI-related hypophysitis occupying the middle ground. Moreover, our study reveals new aspects of anti-POMC antibodies in patients with paraneoplastic ACTH deficiency. This report expands our understanding of the immunological landscape and provides new insights for the identification of antibodies associated with paraneoplastic autoimmune ACTH deficiency.