Rationale:Rheumatoid arthritis (RA) and axial spondyloarthritis (axSpA) are distinct inflammatory rheumatic diseases with different clinical, serological, and genetic profiles. RA is typically characterized by symmetric peripheral polyarthritis and autoantibody positivity, particularly anti-cyclic citrullinated peptide (anti-CCP), whereas axSpA primarily involves the axial skeleton and sacroiliac joints and is often associated with human leukocyte antigen-B27 (HLA-B27). The coexistence of seropositive RA and axSpA is uncommon and presents diagnostic and therapeutic challenges, particularly when axial symptoms are under-recognized in young patients. This case highlights a rare overlap phenotype and emphasizes the role of advanced imaging and individualized management.Patient concerns:An 18-year-old Saudi woman presented with inflammatory peripheral joint pain, associated with chronic axial symptoms suggestive of sacroiliac involvement.Diagnoses:Laboratory investigations revealed markedly elevated anti-cyclic citrullinated peptide (anti-CCP) antibodies (373 U/mL), supporting the diagnosis of seropositive RA based on the 2010 American College of Rheumatology/European Alliance of Associations for Rheumatology criteria. Magnetic resonance imaging of the sacroiliac joints demonstrated bilateral sacroiliitis with active inflammatory changes, fulfilling the Assessment of SpondyloArthritis International Society (ASAS) criteria for axial spondyloarthritis, despite negative HLA-B27 and absence of other typical spondyloarthritis features.Interventions:The patient was initially managed with methotrexate (15 mg/wk) and low-dose prednisone (5 mg/d). Due to persistent axial symptoms, treatment was escalated to adalimumab following appropriate screening and counseling.Outcomes:At 3-month follow-up, the patient demonstrated significant clinical improvement (>70%) in both peripheral and axial symptoms, with normalization of inflammatory markers C-reactive protein (CRP) and erythrocyte sedimentation rate.Lessons:This case underscores the importance of considering overlapping rheumatologic conditions in patients with atypical presentations. Magnetic resonance imaging plays a critical role in detecting axial involvement, particularly in HLA-B27–negative patients. Early recognition of such overlap syndromes is essential to guide appropriate targeted therapy and improve long-term outcomes, especially in young populations.

Heterogeneity in the definition, diagnosis and treatment of primary biliary cholangitis-autoimmune hepatitis (PBC-AIH) is present in guidelines and daily practice. This initiative aimed to establish expert consensus on terminology, diagnosis and management. The initiative was endorsed by the ERN RARE-LIVER, the Global PBC Study Group and the IAIHG, in partnership with the European Society of Pathology. Using a modified RAND/UCLA Appropriateness Method, the Delphi process involved two voting rounds. The final panel comprised 74 hepatologists and 14 liver pathologists from diverse geographic regions. Consensus was reached that PBC-AIH should be defined as a variant rather than an overlap syndrome. Additional agreement was achieved on diagnostic criteria and the prerequisite of liver biopsy to make the diagnosis. The panel agreed that the diagnosis should be periodically re-evaluated, since features can occur sequentially, and that PBC-AIH is associated with a worse prognosis than PBC alone unless treated by immunosuppression. The indication and choice of immunosuppressive therapy should be based on severity of interface hepatitis (ideally confirmed by review from an experienced hepatopathologist), disease stage, age, comorbidities, and patient preference. This Delphi initiative established consensus in a complex, understudied area lacking evidence-based guidelines. The resulting statements offer a basis for prospective studies and standardized clinical protocols, aiming to enhance consistent management of PBC-AIH.

We report two cases of overlap syndrome between IgG4-related disease (IgG4-RD) and systemic lupus erythematosus (SLE), encountered in distinct rheumatology centers in France and Romania. The co-occurrence of SLE and IgG4-RD is rare, and both cases highlight the intersection of these autoimmune conditions. The overlapping features of both diseases present a diagnostic challenge but offer an opportunity for a greater understanding of the pathophysiological interactions between IgG4-RD and SLE. Clinicians must be vigilant in distinguishing between these entities, as they carry different therapeutic implications.

ABSTRACTImmune checkpoint inhibitor (ICI) therapies are known to cause immune‐related adverse events (irAEs), including life‐threatening myocarditis, myositis, and myasthenia (MMM) overlap syndrome. Current literature lacks established therapeutic guidelines for effective management with steroid‐sparing agents. In this paper, we report the successful treatment of MMM with baricitinib in conjunction with abatacept (CTLA‐4‐Ig) in a single patient. We report two cases with a history of locally advanced malignancies treated surgically who were receiving adjuvant ICI therapy and subsequently developed MMM overlap syndrome. Case A was treated with high‐dose corticosteroids, IVIG, and mycophenolate mofetil with no improvement and subsequently expired due to respiratory failure and cardiac arrest. On the other hand, Case B showed improvement of myocarditis and myositis with high‐dose corticosteroids, abatacept, and mycophenolate mofetil. However, myasthenic symptoms progressed. Discontinuation of mycophenolate mofetil and initiation of baricitinib resulted in a complete recovery at 2‐month follow‐up. The use of baricitinib in combination with abatacept resulted in significant improvement of ICI‐induced MMM in our patient. We propose that in patients with ICI‐induced MMM, baricitinib with abatacept can be used effectively with successful outcomes, especially for refractory myasthenic symptoms. Further clinical trials on the use of JAK inhibitors alone or in combination with abatacept will be beneficial in determining its efficacy.

Widespread Muscle Loss in Autoimmune Hepatitis and Its Adverse Prognostic Impact.

Sarcoidosis is a granulomatous disease that affects multiple organs; however, pituitary involvement is extremely rare. Although autoimmune diseases, such as Sjögren's disease (SjD), may coexist, overlapping cases presenting with hypopituitarism are exceedingly rare. A 76-year-old man was admitted with hyponatremia and altered consciousness as chief complaints. Endocrine testing revealed panhypopituitarism, and magnetic resonance imaging showed pituitary gland and pituitary stalk enlargement with homogeneous enhancement. Whole-body imaging revealed extensive lymphadenopathy. Histological examination of lymph node and lung biopsy specimens revealed non-necrotizing granulomas, indicative of sarcoidosis. Salivary gland biopsy and autoantibody testing confirmed the presence of concomitant SjD. Hormone replacement therapy markedly improved pituitary enlargement and pituitary hormone secretion, allowing the discontinuation of replacement therapy after 137 days. However, despite the improvement in pituitary and lymph node lesions, interstitial pneumonia subsequently developed due to SjD, necessitating systemic immunosuppressive therapy. In conclusion, this case demonstrates a rare overlap between sarcoidosis presenting with hypopituitarism and SjD, in which pituitary lesions improved, but immune activity progressed in other organs. Thus, immune-mediated disease activity may differ between organs in overlapping syndromes, and pituitary lesions in sarcoidosis do not necessarily parallel systemic disease activity.

Introduction and importance: An overlap syndrome is a condition when there is coexistence of two or more autoimmune connective tissue disease, which is very rare and diagnostically challenging. Dermatomyositis is an autoimmune condition that presents with skin manifestations, progressive muscular weakness, and inflammation. Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune condition mainly affecting skin, joints, kidneys, and brain. Early recognition and therapeutic intervention are necessary in overlap syndromes to prevent the patient from having severe cardiopulmonary problems. Case presentation: This is a case of a 32-year-old woman diagnosed with SLE who developed progressive muscle weakness (3/5 strength proximally) and a distinctive rash, classic signs of dermatomyositis from last 2 months. Laboratory tests have shown elevated creatine kinase (3500 U/l), positive ANA (1:640), anti-dsDNA, and anti-Jo-1 antibodies, along with visible myopathic alterations on electromyographs; unique results on muscle and skin biopsies were all confirmed by investigations. Clinical discussion: After confirming the diagnosis of dermatomyositis, the patient condition was managed by high dose corticosteroids (prednisolone 1 mg/kg/day), intravenous immunoglobulin for severe muscle weakness, methotrexate, high-dose corticosteroids, and physical therapy. Conclusion: This case highlights the complexity of diagnosis in distinguishing the true dermatomyositis from SLE associated inflammatory myopathy in young adults. It emphasizes the importance of early recognition of DM-SLE overlap syndrome through targeted investigations integrating clinical, serological, and histopathological assessment; that can alter the disease trajectory. The case emphasizes the importance of maintaining high clinical suspicion in patients with autoimmune diseases while guiding the immunosuppressive therapy.

Background Frontotemporal dementia is an umbrella term that encompasses several clinical syndromes with impaired behavioral, language, and motor functions. These syndromes show considerable overlap in clinical features and imaging patterns. Therefore, there is a need to investigate the syndromic heterogeneity in FTD using unbiased data-driven approaches. Methods We used data-driven clustering analysis of structural magnetic resonance imaging (MRI) data on 400 patients with clinical FTD diagnoses [behavioral variant of frontotemporal dementia (bvFTD), semantic variant of primary progressive aphasia (svPPA), right temporal variant of frontotemporal dementia (rtvFTD), apraxia of speech with agrammatic aphasia (AOS-PAA), primary progressive apraxia of speech (PPAOS), progressive supranuclear palsy (PSP), corticobasal syndrome (CBS) and primary progressive aphasia who did not fit into the other diagnostic categories (PPA-other)]. MR images were w-scored relative to cognitively unimpaired individuals, and principal component analysis was performed. A clustering ensemble approach, including hierarchical algorithms, was applied to the MR-based principal components, and imaging and clinical characteristics of the clusters were investigated. Various numbers of clusters ( K = 2, 3, or 4) were evaluated. Results The K = 3 solution offered the most clinically meaningful separation of FTD syndromes. The first cluster captured mostly frontal MRI abnormalities related to the speech, language and behavioral clinical dimensions, including patients with AOS-PAA, PPAOS, PPA-other, and bvFTD. The second cluster captured mostly temporal abnormalities and included mainly patients with svPPA and rtvFTD, but also bvFTD, AOS-PAA, and PPA-other. The third cluster captured cortical and subcortical atrophy, particularly in the midbrain, and included atypical Parkinsonian syndromes, with all PSP and CBS patients captured in this cluster, as well as most PPAOS patients. Considerable overlap of clinical syndromes was noted across these clusters, whereby patients with AOS-PAA, svPPA, PPA-other, and bvFTD were captured in more than one cluster. Discussion Our findings highlight heterogeneity in FTD, which mainly exists along three axes: speech, language and behavioral deficits reflecting frontal atrophy, language deficits reflecting temporal atrophy, and motor and motor speech deficits reflecting mostly midbrain and subcortical atrophy, with cortical involvement.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Overlap Induced by Trimethoprim/Sulfamethoxazole: A Case Report

Autoimmune hepatitis (AIH) overlap syndromes are conditions wherein features of AIH coexist with those of primary sclerosing cholangitis (PSC) or primary biliary cholangitis (PBC). We aimed to evaluate their clinical presentation, treatment response, and disease outcome in an Arab cohort. AIH overlap patients, based on the Paris criteria for PBC/AIH overlap ( n = 19), and revised International Autoimmune Hepatitis Group (IAIHG) score for PSC/AIH overlap ( n = 17) were reviewed at a single center in Saudi Arabia, from 2001 to 2024. Biopsy-proven standalone AIH patients ( n = 93) were included as controls. The primary endpoint was disease progression, liver transplantation, or mortality. Overall, the AIH and overlap syndrome cohorts were diagnosed at similar ages. Post-treatment Model for End-stage Liver Disease (MELD) and Child-Turcotte-Pugh (CTP) scores did not improve in the PBC/AIH cohort ( P > 0.05), while in PSC/AIH, the CTP ( P = 0.005) and Mayo Clinic scores improved ( P = 0.002). In PBC/AIH and PSC/AIH cohorts, disease progression and disease remission rates were comparable. The median relapse-free survival (RFS) was 10.4 years for PBC/AIH, and 13.8 years for PSC/AIH cohorts ( P = 0.256). The 5- and 10-year RFS rates for the AIH, PBC/AIH, and PSC/AIH cohorts were 92.3% and 72.7%, 81.3% and 53.4%, and 81.4% and 67.9%, respectively. Higher initial Mayo ( P = 0.035) and CTP score ( P = 0.028) predicted development of disease composite endpoint (disease progression, liver transplantation, or death). Despite lack of standardized treatment protocols, AIH, and overlap syndromes respond comparably well to treatment, in addition to similar disease remission and RFS between PBC/AIH and PSC/AIH patients. More extended follow-up studies are warranted for patients with overlap syndrome.

Abstract T-cell dysregulation caused by immune checkpoint inhibitors (ICIs) can lead to a rare and often fatal overlap syndrome consisting of myositis, myocarditis, and myasthenia gravis (IM3OS). We present a case of IM3OS following combination ICI therapy for melanoma. A 71-year-old male with melanoma, status post 2 cycles of ipilimumab and nivolumab, presented with myalgias, proximal muscle weakness, dysarthria, encephalopathy, and hypercapnic respiratory failure requiring intubation. Workup revealed a troponin of 10,000 ng/L, diffuse ST-segment depressions, preserved left ventricular function without regional wall motion abnormalities, and a non-obstructive cardiac catheterization. Additional findings included creatine kinase (CK) of 4,000 U/L, negative aldolase, positive acetylcholine receptor (AChR) antibodies, negative muscle-specific kinase (MuSK) antibodies, and electromyography (EMG) with myopathic pattern. These findings raised concern for ICI-induced IM3OS. High dose methylprednisolone (1g/day) and intravenous immunoglobulin (IVIG) were initiated for 5 days with symptomatic and laboratory improvement. Rituximab was considered but deferred given unclear additional benefit. The patient subsequently underwent tracheostomy with plans for discharge to long-term care facility for ventilator weaning. However, his course was complicated by recurrent infections and hemodynamic instability, after which goals of care were redirected toward comfort. ICIs block inhibitory pathways exploited by cancer cells to evade immune detection. However, this can lead to T-cell dysregulation and molecular mimicry against shared antigens within the skeletal muscle, myocardium, and neuromuscular junction, resulting in this rare overlap syndrome. IM3OS carries a high in-hospital mortality rate of 60% and an incidence of less than 1% in ICI-treated patients. Symptoms typically arise after 1-2 ICI doses. Neuromuscular symptoms often precede cardiac involvement. Combination ICI therapy has a threefold higher incidence of inflammatory myopathies than monotherapy, and an earlier onset of symptoms. Diagnostic workup includes CK, aldolase, and myositis panel if concurrent myositis is suspected, as well as a cardiac MRI typically showing late subepicardial gadolinium enhancement and endomyocardial biopsy with lymphocytic infiltration and myocyte injury. AChR and MuSK autoantibodies are often detected, but seronegative myasthenia gravis can occur. Data on optimal treatment is limited, but includes high dose steroids, and IVIG or plasmapheresis. Immunosuppressants such as rituximab or mycophenolate are considered in steroid-refractory cases. Emerging data suggests a link between IM3OS and striational antibodies, which could be utilized as biomarkers for early detection. This case illustrates the rarity, high mortality, and therapeutic challenges surrounding IM3OS, highlighting the need for early recognition and prompt treatment. Further investigation is warranted to optimize treatment strategies and improve outcomes. This abstract is funded by: None

Prevalence of anti-mitochondrial antibodies and clinical features in autoimmune hepatitis (AIH) patients.

Indian National Association for Study of the Liver Guidance Document on Difficult to Treat Autoimmune Hepatitis.

The clinical impact of hepatic steatosis (HS) among patients with autoimmune liver disease (AILD) remains unclear. We aim to determine the prevalence of HS and its clinical impact on treatment response and outcomes in patients with AILD. We systematically searched 3 electronic databases until 17 December 2025, including all studies that reported the prevalence, clinical impact, and treatment response of AILD patients with concomitant HS. The temporal trend of HS prevalence was analyzed using a quasi-Poisson regression model, with annual percent changes (APC, %) calculated. Overall, 44 studies, comprising 19,898 patients with autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) were included. The pooled prevalence of HS in patients with AIH, PBC, and PSC was 27.3%, 32.9%, and 21.6%, respectively. HS prevalence has significantly increased among PBC patients since 2010 (APC: +37.4%). While concomitant HS was associated with a higher risk of hepatic decompensation (OR: 1.6, 95% CI: 1.3-2.1, I2=0%) and hepatocellular carcinoma (OR: 1.8, 95% CI: 1.3-2.6, I2=0%) in patients with AIH, HS did not influence the clinical outcomes in patients with PBC. Treatment response in AIH and PBC was not influenced by concomitant HS. Available data on PSC with concomitant HS were insufficient to assess its association with clinical outcomes. AIH patients with concomitant HS had worse outcomes than those without HS; whereas HS did not influence the clinical outcomes in patients with PBC. Future research evaluating the impact of HS on PSC and overlap syndrome is much needed.

Liver involvement, particularly autoimmune hepatitis (AIH) overlap, is a rare but clinically important manifestation of systemic sclerosis (SSc). This study aimed to assess the prevalence, clinical characteristics, and diagnostic utility of laboratory parameters for identifying AIH in a cohort of patients with SSc. We retrospectively analyzed 111 patients with SSc. Clinical characteristics, autoantibody profiles, and laboratory parameters were compared between patients with and without AIH. AIH diagnosis was confirmed by liver biopsy in all cases. Given the small number of events, Firth's penalized likelihood logistic regression was applied to identify independent risk factors. The diagnostic performance of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and serum IgG levels was evaluated using receiver operating characteristic (ROC) curve analysis. Prior methotrexate (MTX) exposure was recorded, and the potential confounding effect of MTX-induced liver enzyme elevations was assessed. Autoimmune hepatitis (AIH) was identified in 8 of 111 patients (7.2%). All AIH-positive patients showed interface hepatitis on liver biopsy. There were no significant differences between AIH-positive and AIH-negative patients regarding age, systemic sclerosis subtype, or presence of interstitial lung disease (all p > 0.05). Firth's penalized logistic regression indicated that diffuse cutaneous SSc, anti-Scl-70 positivity, and interstitial lung disease were not independent predictors of AIH overlap. In receiver operating characteristic analysis, alanine aminotransferase (ALT) demonstrated the highest diagnostic performance (AUC 0.88, 95% CI 0.76-0.99; p < 0.001), with a sensitivity of 87.5% and specificity of 85.4% at a cut-off > 34.5 U/L. Aspartate aminotransferase (AST) (AUC 0.86) and serum IgG (AUC 0.74) also showed significant but lower discriminatory ability. ALT retained high specificity for AIH even among patients with prior MTX exposure, supporting its utility as a non-invasive screening tool in SSc. Autoimmune hepatitis is a rare overlap syndrome in systemic sclerosis that occurs independently of clinical phenotype. Routine monitoring of liver transaminases, particularly ALT, provides a reliable non-invasive screening tool. Clinicians should consider ALT elevations > 34.5 U/L as a trigger for further AIH evaluation, even in patients with prior MTX exposure. Key Points •Autoimmune hepatitis (AIH) represents a clinically significant overlap in systemic sclerosis (SSc), with a prevalence of 7.2% in this cohort, indicating that it may be more common than previously reported when systematic screening is implemented. Biochemical screening rather than biopsy-only evaluation improves detection. •The development of AIH in SSc patients appears to be independent of disease subtype (limited vs. diffuse), specific autoantibody profiles (Anti-Scl70, ACA), or major organ involvement, such as interstitial lung disease. •An ALT threshold of > 34.5 U/L provides a practical "red flag" for clinicians, offering high sensitivity and specificity to prompt further diagnostic evaluation, including liver-specific autoantibody testing and liver biopsy when indicated. This threshold should be interpreted cautiously in patients with prior methotrexate (MTX) exposure, as mild ALT elevations may also reflect drug-related hepatotoxicity. •An ALT threshold of > 34.5 U/L provides a practical "red flag" for clinicians, offering high sensitivity and specificity to prompt further diagnostic evaluation, including liver-specific autoantibody testing and liver biopsy when indicated. •Because AIH can develop across the full spectrum of SSc regardless of systemic disease severity, routine monitoring of transaminases is essential for early detection and timely initiation of immunosuppressive therapy.

Background/Objectives: Hospitalisations in systemic lupus erythematosus (SLE) reflect disease severity, accumulated damage, and the burden of comorbidity, remaining a major determinant of healthcare utilisation. Recent evidence suggests a shift from flare-driven admissions toward complications related to infections, comorbidities, and long-term treatment effects. We aimed to analyse the causes, characteristics, and outcomes of hospital admissions in patients with systemic lupus erythematosus (SLE) over a 30-year period in a tertiary referral centre in Catalonia (Spain) and to evaluate changes over time and prognostic factors associated with adverse outcomes. Methods: A retrospective observational study was conducted including all SLE patients admitted to the Department of Autoimmune Diseases at Hospital Clínic de Barcelona between June 1995 and December 2024. Admissions lasting less than 48 h or lacking clinical documentation were excluded. Variables analysed included demographics, disease duration, comorbidities, cause of admission, treatments, and outcomes. A composite outcome was defined as intensive care unit (ICU) admission, 30-day readmission, or prolonged hospital stay. Statistical analyses included univariate and multivariate regression models. Results: Among the 1216 hospital admissions, SLE flares and infections were the most frequent causes. Over the study period, admissions due to infections increased significantly and, in the last five years, exceeded those related to disease flares (33.7% vs. 26.1%). Patients hospitalized for flares were younger and had a shorter disease duration, whereas infection-related admissions were more common among older patients, those with overlap syndromes, and those with higher damage scores. Vascular events and SLE flares were independently associated with poorer outcomes. Although antimalarial use increased over time, it remained suboptimal, largely due to drug toxicity and newly diagnosed cases (from 45.2% to 69.7%; p < 0.001). Treatment strategies also evolved, with a shift toward lower glucocorticoid doses (from 14.5% to 38.3%; p < 0.001), and mycophenolate mofetil replacing cyclophosphamide as the preferred immunosuppressive agent. Conclusions: Hospitalisation patterns in SLE have shifted over time, with infections emerging as the leading cause of admission. This trend reflects an evolving patient profile characterized by older age, greater accumulated damage, comorbidities, and increased exposure to immunosuppressive therapies. These findings underscore the need for optimized infection prevention strategies and individualized treatment approaches to improve outcomes in contemporary SLE care.

Introduction Systemic sclerosis (SSc) is an autoimmune connective tissue disease that may progress with multi-organ involvement. Both genetic predisposition and environmental factors are implicated in its pathogenesis. However, their exact roles remain incompletely understood. Case description A 59-year-old non-smoking man with a non-contributory family history who has worked as a foundry worker for 35 years, with exposure to silica-containing dust, was admitted to the clinic due to pain and swelling of the fingers, progressive skin tightness, Raynaud’s phenomenon, pitted scars on the fingertips, exertional dyspnea and dysphagia. The patient reported symptom onset approximately 16 years earlier, with arrhythmia and conduction disorder requiring pacemaker implantation. One year earlier, the patient was diagnosed with dyspnea at the pulmonological department. Chest computed tomography (CT) revealed numerous enlarged, calcified mediastinal lymph nodes, pleural thickening at the lung apices and multiple, scattered, well-calcified perilymphatic nodules, predominantly in the upper lobes and subpleural regions, along with features of emphysema. Findings were consistent with silicosis given silica exposure. Bronchoscopy and lymph node cytology (BAC) were unremarkable; bronchial secretions and acid-fast bacilli microscopy were negative. Rheumatological evaluation revealed markedly elevated inflammatory markers, normocytic anaemia, hypoalbuminemia with hypergammaglobulinemia, and an IgG κ protein with an acute-phase oligoclonal pattern. The levels of C3 and C4, as well as tumour, cardiac, and muscle injury markers, were normal. Antinuclear antibody titers were strongly positive (1 : 5,120) with the presence of anti-Scl-70 and anti-Pm-Scl-100 Abs. Urinalysis showed no proteinuria. Nailfold capillaroscopy indicated SSc, corresponding to the late phase according to Cutolo (Figs. 1,2). In addition to silicosis-related findings, CT demonstrated basal ground-glass opacities consistent with SSc-related non-specific interstitial pneumonia (Fig. 3). The patient met the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology classification criteria for the diagnosis of SSc. Conclusions Long-term occupational exposure, including high silicon content, may contribute to the development of SSc. Abnormalities in lung imaging may be both a consequence of SSc and a result of environmental factors. It remains unclear whether the clinical presentation is at tributable to chemical exposure (Erasmus’ syndrome) or represents pulmonary involvement in the course of overlap syndrome. Treatment decisions, including antifibrotic therapy, require prior evaluation of pulmonary changes.

Introduction Selective immunoglobulin A deficiency (SIgAD) is the most common primary immunodeficiency. Although most patients remain asymptomatic, SIgAD is frequently associated with autoimmune and allergic diseases, while infections occur considerably less often than in common variable immunodeficiency (CVID). The aim of the study was to examine the prevalence of SIgAD among patients with inflammatory and autoimmune diseases, to characterise their infectious risk and immunological abnormalities, and to compare their clinical and laboratory parameters with those observed in CVID. The SIgAD was diagnosed when the serum sensitive IgA level was 0.7 g/l. Material and Methods Among patients treated for autoimmune/inflammatory conditions at the Rheumatology and Immunology Clinic of the University of Debrecen, SIgAD was confirmed in 33 patients (27 women, 6 men; average age 54.15 ±13.4 years, and average sensitive IgA 0.31 g/l). The CVID (defined as IgG 6 g/l with low IgA, IgM levels) was diagnosed in 10 patients (8 women, 2 men; average age 60.6 ±15.6 years). Results In the SIgAD group, recurrent non-severe infections (mainly upper respiratory and urinary tract infections) occurred in 11 patients (33.3%). Allergic diseases (asthma, pollen allergy, atopic dermatitis) were present in 19 cases (57.6%), and concomitant malignancy in 4 patients (12.1%). The underlying autoimmune diseases included rheumatoid arthritis (n = 12), systemic lupus erythematosus or rheumatoid arthritis–systemic lupus erythematosus overlap syndrome (n = 7), undifferentiated connective tissue disease (n = 8), spondyloarthropathy (n = 2), myositis (n = 1), polymyalgia rheumatica (n = 2), and scleromyxedema (n = 1). Allergic and celiac diseases occurred significantly more frequently in SIgAD than in CVID, whereas malignant diseases were significantly less common. Immunophenotypic analysis revealed that the proportion of CD8+ naïve T cells (40.44%) was significantly higher in SIgAD compared to CVID (34.4%, p = 0.05). The proportion of CD19 naïve B cells was significantly lower and showed a strong positive correlation with decreased IgA levels (R = 0.52, p = 0.003). In contrast, CD19+ IgM memory B cells were significantly increased and were associated with the more frequent occurrence of allergic and neoplastic diseases. Discussion Patients with SIgAD exhibit significant abnormalities in both humoral and cellular immune responses. Conclusions Determining the subtypes of T- and B-cells may contribute to a better understanding of disease pathogenesis and may help identify patients at increased risk for additional comorbidities.

Bickerstaff Brainstem Encephalitis (BBE) is a rare, post-infectious autoimmune disorder characterized by ophthalmoplegia, ataxia, and altered consciousness. Its significant clinical and serological overlap with Miller Fisher syndrome (MFS) and Guillain-Barré syndrome (GBS) creates diagnostic challenges, particularly in atypical or seronegative presentations. These conditions are collectively understood as components of the anti-GQ1b antibody syndrome, a spectrum of neuro-immune disorders. This review provides a clinically focused, integrative synthesis of the anti-GQ1b antibody spectrum, with an emphasis on BBE. We aim to clarify the underlying pathophysiology, delineate the range of clinical phenotypes, provide a structured framework for diagnosis that acknowledges the limitations of ancillary testing, and summarize current evidence for therapeutic strategies. Pathogenesis is primarily driven by anti-GQ1b IgG antibodies, generated following infection via molecular mimicry, which trigger complement-mediated damage to ganglioside-rich neural structures. The clinical presentation ranges from purely peripheral deficits (MFS) to severe central nervous system dysfunction (BBE), with frequent BBE-GBS overlap syndromes. Diagnosis hinges on clinical recognition, supported by serology, with neuroimaging serving a crucial role in excluding mimics. Approximately one-third of clinically defined BBE cases are seronegative, suggesting alternative mechanisms. Prompt immunotherapy with intravenous immunoglobulin (IVIg) or plasma exchange is the cornerstone of management, extrapolated from GBS trials, while evidence for corticosteroids remains limited. A structured, spectrum-based perspective remains essential for clinicians navigating the diagnostic complexities of the anti-GQ1b antibody syndromes. This updated synthesis is intended to enhance diagnostic accuracy, guide therapeutic reasoning across the full range of phenotypes, and highlight key unresolved questions to inform a future research agenda.

Objectives Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) together is known as overlap syndrome. This study evaluated whether overlap syndrome is associated with worse inpatient outcomes after total hip arthroplasty (THA) compared with COPD alone. Methods Adult patients (≥18 years) with COPD undergoing elective THA were identified from the National Inpatient Sample database. Propensity-score matching (PSM) balanced baseline differences between patients with COPD–OSA overlap syndrome and those with COPD alone. Regression analyses evaluated in-hospital mortality, length of hospital stay, unfavorable discharge, and postoperative complications. Results After PSM, 25,926 patients were included. Compared with COPD alone, patients with COPD–OSA overlap had higher rates of unfavorable discharge (36.0% vs 29.7%), respiratory failure (3.6% vs 1.7%), and acute kidney injury (AKI) (6.3% vs 3.8%). In adjusted analyses, COPD–OSA overlap was significantly associated with higher risks of unfavorable discharge (aOR = 1.10, 95% CI: 1.03, 1.18), respiratory failure (aOR = 1.65, 95% CI: 1.37, 1.99), and AKI (aOR = 1.18, 95% CI: 1.03, 1.35). Age-stratified analyses demonstrated increased respiratory risk in patients ≥70 years, whereas younger patients had higher risks of both respiratory failure and AKI. Conclusion Among patients undergoing elective THA, COPD–OSA overlap syndrome is associated with increased adverse inpatient outcomes.