In Situ Activation of Pituitary-Infiltrating T Lymphocytes in Autoimmune Hypophysitis

Clinical features of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis: a new aspect of paraneoplastic autoimmune condition

The pathogenesis of anti-pituitary-specific transcription factor-1 (PIT-1) hypophysitis was gradually revealed as cases emerged. Our comprehensive analysis, including all reported cases, identified a new instance of anti-PIT-1 hypophysitis postimmune checkpoint inhibitor therapy. All 9 patients exhibited extremely low growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH) levels; 2 had a slightly atrophic pituitary gland; 4 had thymoma, and 5 had malignant neoplasms of diffuse large B-cell lymphoma (DLBCL) and other origins. Patients with thymoma showed multiple autoimmune diseases. HLA-A*24:02 and/or A*02:06 were present in six and DR53 in 5 cases analyzed. High anti-PIT-1 antibody titers and ectopic PIT-1 expression in the cytosol and nucleus of the tumor tissues were observed in patients with thymoma or DLBCL, whereas it was exclusively observed in the nuclei of a bladder cancer patient. These findings provide new insights into the pathophysiology of paraneoplastic autoimmune hypophysitis.

Unveiling the Etiopathogenic Spectrum of Hypophysitis: A Narrative Review

Hypophysitis, a rare inflammatory disorder of the pituitary gland, has seen an uptick in reported cases in recent years. Our objective is to summarize the most recent research on the etiopathogenesis, molecular mechanisms, and genetics of both primary and secondary hypophysitis. Primary autoimmune hypophysitis (PAH): During the acute phase of the disease, the pituitary gland in enlarged due to the infiltration of T and B lymphocytes. The chronic phase is characterized by progressive and irreversible pituitary atrophy. APA may play a role in the management, diagnosis, and prognosis of PAH. Specific autoantibodies such as anti-GH, anti-PIT-1, and anti-T-PIT have been found in patients with hypophysitis and hypopituitarism. A recent study suggested that a mechanism of escaping clonal deletion and mounting an immune response against self antigens can explain the unusual nature of the immune response observed in PAH patients. A cytokine array shows the presence of gamma-interferon and interleukin-17. Patients carrying mutations in the PIT1 or PROP1 genes may present PAH. Individuals carrying the HLA DQ8 haplotype are four times more likely to develop PAH. Immune checkpoint inhibitors induce hypophysitis (IIHs): IIHs is an increasingly frequent toxicity of in patients on treatment with inhibitors targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death-1 (PD-1). ICIs inhibit the CTLA-4 pathway, leading to overactivation of T lymphocytes. The binding of PD-1/PD-L1 suppresses the activity of T cells, promotes the conversion of T-helpers into T-regulatory cells, and activates pro-survival signaling pathways in cancer cells. Cytokines play a crucial role in IIHs. B-cell infiltration has been observed in IIHs, suggesting that antibody-mediated pituitary injury may contribute. Genetic polymorphisms of CTLA-4 and PD-1 genes can increase the risk of IIHs. HLA alleles may also be involved in the onset of IIHs; this HLA association presents a possible alternative mechanistic hypothesis. IIHs may also be linked to a paraneoplastic syndrome triggered by ectopic expression of pituitary specific antigens. SARS-CoV-2-related hypophysitis: Recently, the literature has reported occurrences of hypophysitis associated with the SARS-CoV-2 virus; long COVID-19 may also present as infundibulo-neuro-hypophysitis. The virus enters the central nervous system because of its distinct interaction with angiotensin-converting enzyme receptors via spike proteins binding the capillary endothelium, and it directly damages the pituitary cells. The effect of SARS-CoV-2 can occur indirectly through inflammation and the release of cytokines. The exact mechanism remains ambiguous. The available data on endocrine complications associated with the SARS-CoV-2 vaccine are scant. Nonetheless, isolated cases of hypophysitis have been documented. Treatment of hypophysitis: Glucocorticoids are the cornerstone in managing primary hypophysitis, given their targeted action on inflammation. A better understanding of the etiopathogenesis and molecular mechanism of hypophysitis can lead to more effective and personalized treatment strategies.

A lesion-selective albumin-CTLA4Ig as a safe and effective treatment for collagen-induced arthritis

BACKGROUND

CTLA4Ig is a dimeric fusion protein of the extracellular domain of cytotoxic T-lymphocyte protein 4 (CTLA4) and an Fc (Ig) fragment of human IgG₁ that is approved for treating rheumatoid arthritis. However, CTLA4Ig may induce adverse effects. Developing a lesion-selective variant of CTLA4Ig may improve safety while maintaining the efficacy of the treatment.

METHODS

We linked albumin to the N-terminus of CTLA4Ig (termed Alb-CTLA4Ig) via a substrate sequence of matrix metalloproteinase (MMP). The binding activities and the biological activities of Alb-CTLA4Ig before and after MMP digestion were analyzed by a cell-based ELISA and an in vitro Jurkat T cell activation assay. The efficacy and safety of Alb-CTLA4Ig in treating joint inflammation were tested in mouse collagen-induced arthritis.

RESULTS

Alb-CTLA4Ig is stable and inactive under physiological conditions but can be fully activated by MMPs. The binding activity of nondigested Alb-CTLA4Ig was at least 10,000-fold weaker than that of MMP-digested Alb-CTLA4Ig. Nondigested Alb-CTLA4Ig was unable to inhibit Jurkat T cell activation, whereas MMP-digested Alb-CTLA4Ig was as potent as conventional CTLA4Ig in inhibiting the T cells. Alb-CTLA4Ig was converted to CTLA4Ig in the inflamed joints to treat mouse collagen-induced arthritis, showing similar efficacy to that of conventional CTLA4Ig. In contrast to conventional CTLA4Ig, Alb-CTLA4Ig did not inhibit the antimicrobial responses in the spleens of the treated mice.

CONCLUSIONS

Our study indicates that Alb-CTLA4Ig can be activated by MMPs to suppress tissue inflammation in situ. Thus, Alb-CTLA4Ig is a safe and effective treatment for collagen-induced arthritis in mice.

Inhibition of IRAK1 Is an Effective Therapy for Autoimmune Hypophysitis in Mice

Autoimmune hypophysitis (AH) is an autoimmune disease of the pituitary for which the pathogenesis is incompletely known. AH is often treated with corticosteroids; however, steroids may lead to considerable side effects. Using a mouse model of AH (experimental autoimmune hypophysitis, EAH), we show that interleukin-1 receptor-associated kinase 1 (IRAK1) is upregulated in the pituitaries of mice that developed EAH. We identified rosoxacin as a specific inhibitor for IRAK1 and found it could treat EAH. Rosoxacin treatment at an early stage (day 0-13) slightly reduced disease severity, whereas treatment at a later stage (day 14-27) significantly suppressed EAH. Further investigation indicated rosoxacin reduced production of autoantigen-specific antibodies. Rosoxacin downregulated production of cytokines and chemokines that may dampen T cell differentiation or recruitment to the pituitary. Finally, rosoxacin downregulated class II major histocompatibility complex expression on antigen-presenting cells that may lead to impaired activation of autoantigen-specific T cells. These data suggest that IRAK1 may play a pathogenic role in AH and that rosoxacin may be an effective drug for AH and other inflammatory diseases involving IRAK1 dysregulation.

Holistic Approach to Immune Checkpoint Inhibitor-Related Adverse Events

Immune checkpoint inhibitors (ICIs) block inhibitory molecules, such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), or its ligand, programmed cell death protein ligand 1 (PD-L1) and enhance antitumor T-cell activity. ICIs provide clinical benefits in a percentage of patients with advanced cancers, but they are usually associated with a remarkable spectrum of immune-related adverse events (irAEs) (e.g., rash, colitis, hepatitis, pneumonitis, endocrine, cardiac and musculoskeletal dysfunctions). Particularly patients on combination therapy (e.g., anti-CTLA-4 plus anti-PD-1/PD-L1) experience some form of irAEs. Different mechanisms have been postulated to explain these adverse events. Host factors such as genotype, gut microbiome and pre-existing autoimmune disorders may affect the risk of adverse events. Fatal ICI-related irAEs are due to myocarditis, colitis or pneumonitis. irAEs usually occur within the first months after ICI initiation but can develop as early as after the first dose to years after ICI initiation. Most irAEs resolve pharmacologically, but some appear to be persistent. Glucocorticoids represent the mainstay of management of irAEs, but other immunosuppressive drugs can be used to mitigate refractory irAEs. In the absence of specific trials, several guidelines, based on data from retrospective studies and expert consensus, have been published to guide the management of ICI-related irAEs.

Effect of Immune-Related Adverse Events and Pneumonitis on Prognosis in Advanced Non-Small Cell Lung Cancer: A Comprehensive Systematic Review and Meta-analysis

OBJECTIVE

The correlation between immune-related adverse events (irAEs) and prognosis remains controversial in advanced non-small cell lung cancer (NSCLC). The aim of this study was to systematically evaluate the effect of irAEs, especially checkpoint inhibitor pneumonitis (CIP), on the survival and treatment response in advanced NSCLC.

METHODS

The primary outcomes were overall survival (OS) and objective response rate (ORR). Databases were searched for relevant studies, and meta-analysis was conducted with RevMan.

RESULTS

A total of 51 studies involving 12,600 participants were included. The development of irAEs had an advantageous effect on OS and ORR in advanced NSCLC (OS: hazard ratio [HR], 0.56 [95% confidence interval [CI] 0.46 to 0.67]; ORR: odds ratio [OR], 3.13 [2.41 to 4.06]). The occurrence of endocrine and skin irAEs had advantageous effects on both OS and ORR (endocrine OS, HR, 0.47 [-0.37 to 0.59]; endocrine ORR: OR, 1.90 [1.27 to 2.84]; skin OS: HR, 0.48 [0.38 to 0.61]; skin ORR: OR, 4.30 [2.68 to 6.91]). Severe-grade irAEs resulted in shorter OS than low-grade irAEs (HR, 1.49 [1.06, 2.09]), and multiple irAEs resulted in better ORR compared with 1 irAE (OR, 2.04 [1.41 to 2.94]). The occurrence of CIP had no significant effect on OS (HR, 1.14 [0.70 to 1.86]), but it was associated with better ORR (OR, 2.12 [1.06 to 4.25]). Severe-grade CIP had no effect on OS or ORR, but CIP leading to treatment discontinuation resulted in shorter OS (HR, 2.35 [1.17 to 4.72]).

CONCLUSION

The development of irAEs had advantageous effects on survival and response in advanced NSCLC. CIP had no effect on survival, but it predicted better response.

Hypophysitis: A comprehensive overview

Hypophysitis is defined as inflammation of the pituitary gland. It is a heterogeneous condition as it can originate from different parts of the pituitary gland, can be caused by different pathophysiological processes, and can be isolated or the manifestation of a underlying systemic disease. Hypophysitis usually presents with endocrine deficiencies, including diabetes insipidus, with varying patterns. A subset of patients presents with mass effects. The last decades major progress has been made in the understanding of this disease. New forms are now recognized, new diagnostics are being developed, and specific treatments are proposed. This review provides an overview of the current knowledge on hypophysitis using an aetiology-based approach and provides the clinician with a stepwise approach to the patient with (suspected) hypophysitis.

Molecular and Genetic Immune Biomarkers of Primary and Immune-Therapy Induced Hypophysitis: From Laboratories to the Clinical Practice

Hypophysitis is a rare and potentially life-threatening disease, characterized by an elevated risk of complications, such as the occurrence of acute central hypoadrenalism, persistent hypopituitarism, or the extension of the inflammatory process to the neighboring neurological structures. In recent years, a large number of cases has been described. The diagnosis of hypophysitis is complex because it is based on clinical and radiological criteria. Due to this, the integration of molecular and genetic biomarkers can help physicians in the diagnosis of hypophysitis and play a role in predicting disease outcome. In this paper, we review current knowledge about molecular and genetic biomarkers of hypophysitis with the aim of suggesting a possible integration of these biomarkers in clinical practice.

Markers of humoral and cell-mediated immune response in primary autoimmune hypophysitis: a pilot study

INTRODUCTION

Primary autoimmune hypophysitis (PAHs) is a rare inflammatory disease of the pituitary gland. Although largely investigated, the pathogenesis of PAH is not completely clarified. We aimed to investigate the immune response in PAHs.

MATERIAL AND METHODS

Serum anti-pituitary and anti-hypothalamus antibodies (respectively APAs and AHAs) were investigated though an indirect immunofluorescence on monkey hypophysis and hypothalamus slides, serum cytokines though an array membrane and cell-mediated immunity though the white blood cells count.

RESULTS

Nineteen PAH cases entered the study. APA or AHA were identified in all cases. APA were detected in 13 patients (68.4%) and AHA in 13 patients (68.4%). Ten patients (52.6%) were simultaneously positive for both APA and AHA. The prevalence of APAs and AHAs was higher as compared to those observed in 50 health controls (respectively 14% p < 0.001 and 24% p = 0.004) and in 100 not-secreting pituitary adenoma (NFPAs) (respectively 22% p = 0.002 and 8% p < 0.001). Similarly, the prevalence of simultaneous positivity for APA and AHA (52.9%) was higher as compared to the those detected in patients affected by NFPAs (0%; p < 0.001) and in health controls (16% p = 0.002). No differences were identified between PAHs and controls at qualitative and quantitative analysis of serum cytokines and white blood cells count.

CONCLUSIONS

This study suggest that APA and AHA may be detected in an high percentage of PAH cases and that their simultaneous identification may be useful for the differential diagnosis between PAH and NFPAs, in an appropriate clinical context.

Th17 Cells Contribute to the Pathology of Autoimmune Hypophysitis

Autoimmune hypophysitis is classified as primary if its origin is idiopathic and secondary if it develops as a consequence of treatment with immune checkpoint inhibitors. Expanding use of immunotherapy has been paralleled by the increasing hypophysitis prevalence. However, understanding of the immune responses driving the disease remains limited. Using a mouse model of primary hypophysitis, we have identified CD4⁺ T lymphocytes to be the main pituitary-infiltrating immune cell population. Functional analysis showed that they display a Th17 and Th1/Th17 phenotype. To examine involvement of proinflammatory Th1, Th17, and Th1/17 subsets in hypophysitis, we have isolated RNA from the formalin-fixed paraffin-embedded pituitary specimens from 16 hypophysitis patients (three of whom had hypophysitis secondary to immune checkpoint inhibitors), 10 patients with adenoma, and 23 normal pituitaries obtained at autopsy. Transcript levels of IFN-γ, IL-17A, IL-4, IL-10, TGF-β, CD4, CD8α, and class II MHC transactivator were analyzed by the reverse transcription-quantitative PCR (RT-qPCR). Pituitary glands of patients with hypophysitis showed significantly higher IL-17A, CD4, and class II MHC transactivator mRNA levels compared with adenoma and normal pituitaries. All three secondary hypophysitis patients showed detectable IL-17A levels, but other cytokines were not detected in their pituitaries. Levels of IFN-γ, IL-4, IL-10, and TGF-β did not differ between the groups. TGF-β transcript was found in significantly fewer hypophysitis pituitaries (2 out of 16) compared with adenoma (7 out of 10) and normal pituitaries (11 out of 23). Presence of TGF-β in two hypophysitis patients was associated with significantly lower IL-17A mRNA levels compared with hypophysitis patients with no detectable TGF-β (p = 0.03).

The biomarkers related to immune related adverse events caused by immune checkpoint inhibitors

The enthusiasm for immune checkpoint inhibitors (ICIs), an efficient tumor treatment model different from traditional treatment, is based on their unprecedented antitumor effect, but the occurrence of immune-related adverse events (irAEs) is an obstacle to the prospect of ICI treatment. IrAEs are a discrete toxicity caused by the nonspecific activation of the immune system and can affect almost all tissues and organs. Currently, research on biomarkers mainly focuses on the gastrointestinal tract, endocrine system, skin and lung. Several potential hypotheses concentrate on the overactivation of the immune system, excessive release of inflammatory cytokines, elevated levels of pre-existing autoantibodies, and presence of common antigens between tumors and normal tissues. This review lists the current biomarkers that might predict irAEs and their possible mechanisms for both nonspecific and organ-specific biomarkers. However, the prediction of irAEs remains a major clinical challenge to screen and identify patients who are susceptible to irAEs and likely to benefit from ICIs.

The tumour microenvironment of pituitary neuroendocrine tumours

The tumour microenvironment (TME) includes a variety of non-neoplastic cells and non-cellular elements such as cytokines, growth factors and enzymes surrounding tumour cells. The TME emerged as a key modulator of tumour initiation, progression and invasion, with extensive data available in many cancers, but little is known in pituitary tumours. However, the understanding of the TME of pituitary tumours has advanced thanks to active research in this field over the last decade. Different immune and stromal cell subpopulations, and several cytokines, growth factors and matrix remodelling enzymes, have been characterised in pituitary tumours. Studying the TME in pituitary tumours may lead to a better understanding of tumourigenic mechanisms, identification of biomarkers useful to predict aggressive disease, and development of novel therapies. This review summarises the current knowledge on the different TME cellular/non-cellular elements in pituitary tumours and provides an overview of their role in tumourigenesis, biological behaviour and clinical outcomes.

Immune Response Checkpoint Inhibitors: New Risks of a New Class of Antitumor Agents

The introduction into clinical practice of immune checkpoint inhibitors that block cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein-1 (PD-1), and programmed cell death ligand-1 (PD-L1), has improved the prognosis of patients with malignant neoplasms of diff erent localisation. The antitumour eff ect of immune checkpoint inhibitors is based on blocking CTLA-4 and PD-1/PD-L1 signaling pathways and enhancing lymphocyte antitumour activity. However, inhibition of immune checkpoints may lead to dysregulation of immune responses and appearance of a new type of adverse reactions resulting from changes in the activity of immunocompetent cells. The aim of the study was to analyse adverse reactions associated with the use of immune checkpoint inhibitors. It was demonstrated that the structure of immune-mediated adverse reactions varied depending on the class of immune checkpoint inhibitors. The incidence of immune-mediated adverse reactions was higher with CTLA-4 inhibitors as compared with PD-1/PD-L1 inhibitors, and increased signifi cantly in the case of combination therapy. The treatment with CTLA-4 inhibitors most often resulted in skin reactions (rash, itching), gastrointestinal tract reactions (diarrhea, colitis), and endocrine gland problems (hypophysitis). The treatment with PD-1 inhibitors most often led to respiratory disorders (pneumonitis), and in some cases to gastrointestinal disorders (diarrhea, colitis), skin reactions (rash, itching), and endocrine gland problems (hypothyroidism), but they were less common. The treatment with PD-L1 inhibitors was associated with the development of pneumonitis. The development of immune-mediated adverse reactions may require discontinuation of treatment and administration of immunosuppressants, therefore early diagnosis and timely treatment of complications are important prerequisites for successful antitumour therapy. Further study of the mechanisms of immune-mediated adverse reaction development will optimise antitumour therapy with immune checkpoint inhibitors. 

New insight in endocrine-related adverse events associated to immune checkpoint blockade

Anticancer immunotherapy, in the form of immune checkpoint inhibition, is a paradigm shift that has transformed the care of patients with different types of solid and hematologic cancers. The most notable improvements have been seen in patients with melanoma, non-small-cell lung, bladder, renal, cervical, urotherial, and colorectal cancers, Merkel cell carcinoma, and Hodgkin lymphoma. Monoclonal antibodies (mAbs) targeting immune checkpoints (i.e., anti-CTLA: ipilimumab; anti-PD-1: nivolumab, pembrolizumab; anti-PD-L1: durvalumab, atezolizumab, avelumab) unleash the immune system against tumor cells targeting mainly T cells. Treatment with immune checkpoint inhibitors (ICIs) is associated with a variety of diverse and distinct immune-related adverse events (irAEs), reflecting the mechanistic underpinning of each target (i.e., CTLA-4, and PD-1/PD-L1 network). The most frequent endocrine irAEs associated with anti-PD-1 mAb treatment are thyroid dysfunctions, whereas hypophysitis is mostly linked to anti-CTLA-4 treatment. Type 1 diabetes mellitus and adrenalitis are rare irAEs. Combination therapy (anti-CTLA-4 plus anti-PD-1/PD-L1) can be associated with an increased risk and prevalence of endocrine irAEs. In this paper we discuss the pathophysiological and clinical aspects of irAEs with specific emphasis on endocrine irAEs associated with ICIs. With a growing number of patients treated with ICIs, a tight collaboration among oncologists, endocrinologists and immunologists appears necessary when the circumstances are more challenging and for better management of severe endocrine irAEs. Further investigations are urgently needed to better understand the mechanisms by which different ICIs can induce a variety of endocrine irAEs.

Immunotoxicity from checkpoint inhibitor therapy: clinical features and underlying mechanisms

Immune checkpoint inhibition with monoclonal antibodies is becoming increasingly commonplace in cancer medicine, having contributed to a widening of therapeutic options across oncological indications. Disruption of immune tolerance is the key mechanism of action of checkpoint inhibitors and although immune-related adverse events are a typical class effect of these compounds, the relationship between toxicity and response is not fully understood. Awareness and vigilance are paramount in recognizing potentially life-threatening toxicities and managing them in a timely manner. In this review article, we provide an overview of the clinical features, pathological findings and management principles of common immune-related toxicities, attempting to provide mechanistic insight into an increasingly common complication of cancer therapy.

Autoimmune antibodies correlate with immune checkpoint therapy-induced toxicities

Immune checkpoint (IC) therapy provides substantial benefits to cancer patients but can also cause distinctive toxicities termed immune-related adverse events (irAEs). Biomarkers to predict toxicities will be necessary to improve management of patients receiving IC therapy. We relied on serological analysis of recombinant cDNA expression libraries to evaluate plasma samples from patients treated with IC therapy and identified autoantibodies, both in pretreatment and on-treatment samples prior to the development of irAEs, which correlate with the development of immune-related hypophysitis (anti-GNAL and anti-ITM2B autoantibodies) and pneumonitis (anti-CD74 autoantibody). We developed an enzyme-linked immunosorbent assay and tested additional patient samples to confirm our initial findings. Collectively, our data suggest that autoantibodies may correlate with irAEs related to IC therapy, and specific autoantibodies may be detected early for the management of irAEs.

Immune checkpoint inhibitor therapy-induced hypophysitis ∼ a case series of Taiwanese patients

Immune checkpoint blockade-based immunotherapy is a new modality of cancer treatment with a unique mechanism that has gained increased numbers of indication and is now used in several cancer types. However, immune-related adverse events (irAEs) emerge as a new entity of diseases involving one or multiple organ systems. irAEs could result in interruption of immunotherapy, morbidities or even death. Among various manifestations of irAEs, immune-mediated hypophysitis is rare but important, requiring prompt diagnosis and treatment to avoid life-threatening conditions. We report seven cases of immune-mediated hypophysitis in Taiwan. They suffered from various types of advanced cancer and received different regimens of immune checkpoint inhibitors. The time of onset after initiation of immunotherapy ranged from 5 to 36 weeks. All seven subjects were diagnosed of central adrenal insufficiency, while four of them had primary hypothyroidism. There was no typical finding of infiltrative hypophysitis on the pituitary MRI. There was no documented hormone recovery after diagnosis of hypophysitis, and the tumor responses to immunotherapy were variable in these seven patients. In conclusion, immune-mediated hypophysitis is often irreversible. Fortunately, it can be managed adequately with hormone replacements. Further investigations are warranted to unveil underlying mechanisms and ethnic differences to guide the solutions.

Cystic Lymphocytic Hypophysitis Mimicking Pituitary Apoplexy: Daunting Challenge

BACKGROUND

Inflammatory lesions of the pituitary gland including hypophysitis are poorly understood, and it is difficult to make a correct diagnosis on the basis of only clinical and radiologic findings.

CASE DESCRIPTION

An otherwise healthy 68-year-old man presented with sudden onset of headache, visual impairment, and pituitary insufficiency. Magnetic resonance imaging revealed a pituitary mass with cystic component showing changing intensity on follow-up images. Also, changing density of the lesion was demonstrated on computed tomography over a short period of time. These findings suggested a hemorrhagic lesion, and a preoperative diagnosis of pituitary apoplexy associated with a preexisting pituitary adenoma was made on the basis of clinical and radiologic findings. In the endoscopic endonasal approach for tumor resection, there was neither hematoma nor adenoma. Histopathologic diagnosis was lymphocytic hypophysitis.

CONCLUSIONS

To the best of our knowledge, this is the first case report of hypophysitis with radiologic signal changes over a short period. Vigilant attention regarding the clinical diagnosis of such rare entity is paramount.

Human leucocyte antigens coeliac haplotypes and primary autoimmune hypophysitis in caucasian patients

PURPOSE

Primary hypophysitis is a rare disease, with an autoimmune aetiology. As few papers have investigated genetic of hypophysitis, our aim was to evaluate HLA status in a single-centre series of patients.

PATIENTS AND METHOD

A retrospective, longitudinal and cross-sectional study was conducted. In consecutive Caucasian patients, clinically or histologically diagnosed for primary autoimmune hypophysitis (PAH), the HLA genotype having been determined. This cohort was compared with a control group. Anti-pituitary and anti-hypothalamus auto-antibodies evaluation was included.

RESULTS

16 patients were enrolled. Fourteen patients were female (87.5%). According to HLA-DR status, we found the following: 9 of 16 patients (56.3%) haplotypes that were associated with coeliac disease (CD). Among these, 5 carried the DR7-DQ2 heterozygote haplotype (55.5%) while the remaining ones only the following haplotypes: DR3-DQ2 homozygote (25%), DR4-DQ2 heterozygote (25%), DR4-DQ8 heterozygote (50%) and DR4-DQ8 homozygote (25%), respectively. A total of 12 CD-associated haplotypes were identified. In PAH, we found a significantly higher frequency of patients carrying CD-associated HLA haplotypes as compared to the control group (respectively, 75% vs 48% P = .03; OR: 3.25 95%IC:1.1-10.3), particularly, for DQ2 and DQ8 haplotypes. DQ2 haplotype was detected in 50% of PAH and 38.4% of the control group (P = .3), while DQ8 haplotype in 25% of PAH and 7.2% of the control group (P = .01 OR:4.3 95%IC:1.3-14.7).

CONCLUSION

Our data suggest that PAH and CD share some HLA haplotypes, reinforcing the knowledge of their association. HLA haplotypes, particularly DQ8, may play a role in PAH management and diagnosis, also suggesting the predisposition to other autoimmune diseases.