Incorrect diagnoses in patients with neutralizing anti-interferon-gamma-autoantibodies

Deepening Understanding of the Clinical Features and Diagnostic Approaches to Anti-Interferon-Gamma Autoantibody Associated Adult-Onset Immunodeficiency in the Last 20 Years: A Case Report and Literature Review

Anti-interferon-gamma autoantibody (AIGA)-associated adult-onset immunodeficiency (AOID) is an emerging disease that can lead to serious opportunistic infections, which has a history of 20 years since it was first reported in 2004. It's a hard-detected AOID caused by AIGA. In recent years, there has been an increasing number of reports on the disease, but there is still a lack of consensus on the diagnosis and treatment. We here report a case of a 70-year-old Chinese male who had had AIGA in serum and suffered from recurrent pyothorax. Although his condition improved with antimicrobial therapy each time, his pyothorax frequently relapsed, requiring repeated hospitalizations. A literature review of AIGA-associated AOID was conducted. We searched PubMed, Web of Science, Embase, and the Chinese literature database for manuscripts concerning AIGA. Cases detected with AIGA and met our criteria were included. A total of 502 patients were retrospectively analyzed, with 256 (51.0%) males and 246 (49.0%) females. The majority of patients are from Southeast Asia (98.2%). Lymph node (83.7%) is the most commonly involved organ, followed by the lung (60.6%). Nontuberculous mycobacteria (NTM) was identified as the predominant pathogen reported in 77.49% of the patients. The clinical manifestations are diverse and non-specific for the disease often presenting with multi-organ involvement and multiple infections. Timely identification of patients with AIGA, appropriate diagnosis, and individualized treatment are critical; thus, we propose a reasonable diagnostic criterion and a structured diagnostic and treatment process based on our findings to provide clinicians with comprehensive information for clinical practice.

Utility of 18F-Fluorodeoxyglucose Positron Emission Tomography in Evaluating Disseminated Nontuberculous Mycobacterial Infection in Patients With Anti-interferon-γ Autoantibodies

Background

Managing disseminated nontuberculous mycobacterial (NTM) infection in patients with neutralizing anti-interferon-γ autoantibodies (AIGAs) poses substantial challenges due to the lack of established treatment guidance and predictive tools for clinical outcomes. In this study, we investigated the utility of 18F-fluorodeoxyglucose (2-[18F]FDG) positron emission tomography (PET) in guiding treatment decisions, with a focus on its ability to predict rehospitalization outcomes.

Methods

We conducted a post hoc analysis of the first available 2-[18F]FDG PET scans of patients with AIGAs and disseminated NTM infection from a prospective observational multicenter cohort. Cox proportional hazards regression was used to determine predictors for disease-related rehospitalization within 1 year of the examination.

Results

Of the patients with AIGAs evaluated, 41.9% required rehospitalization within 1 year following the initial 2-[18F]FDG PET evaluation. Slowly growing mycobacteria were isolated in 64.5% of patients. Multivariable analysis identified splenic involvement (adjusted hazard ratio, 7.97; 95% CI, 2.34-27.16; P < .001) as a significant predictor of disease-related rehospitalization within 1 year following the examination. Moreover, mediastinal node involvement (adjusted odds ratio, 14.77; 95% CI, 1.01-216.76; P = .049) and axial skeleton involvement (adjusted odds ratio, 14.93; 95% CI, 1.11-201.43; P = .042) were significantly associated with the isolation of slowly growing mycobacteria.

Conclusions

2-[18F]FDG PET appears useful in initial evaluation of disease extent and microbiology in patients with AIGAs and disseminated NTM infection. Identifying splenic involvement through this modality may help recognize patients at increased risk of disease-related rehospitalization within 1 year. These findings suggest that 2-[18F]FDG PET could inform management decisions in this challenging population.

Case report: Systemic multi-organ involvement in an adult-onset immunodeficiency patient infected with Talaromyces marneffei

Adult-onset immunodeficiency (AOID) mediated by anti-interferon-γ autoantibodies (AIGA) is a rare condition, particularly prevalent in Southeast Asia and southern China. We present a case study of a 62-year-old female with AOID who developed a severe pulmonary infection caused by Talaromyces marneffei (TM), leading to acute respiratory failure, generalized rash, multiple lymphadenopathies, bone destruction, and a mediastinal mass. Treatment included mechanical ventilation, antifungal medication, and corticosteroids, resulting in complete recovery and discharge. This case underscores the challenges of managing complex infections in AOID patients and highlights the importance of early diagnosis through metagenomic next-generation sequencing (mNGS) and appropriate intervention to improve clinical outcomes.

Association of the Reduced Levels of Monocyte Chemoattractant Protein-1 with Herpes Zoster in Rheumatoid Arthritis Patients Treated with Janus Kinase Inhibitors in a Single-Center Cohort

Anti-interferon (IFN)-γ autoantibodies are linked to varicella zoster virus (VZV) infection. Given the elevated risks of herpes zoster (HZ) in rheumatoid arthritis (RA) patients treated with Janus kinase inhibitors (JAKis), we aimed to examine the relationship between anti-IFN-γ autoantibodies with HZ development in JAKi-treated patients. Serum titers of anti-IFN-γ autoantibodies, plasma levels of IFN-γ, monocyte chemoattractant protein-1 (MCP-1), and IFN-γ-inducible protein-10 (IP-10) were measured by ELISA. Among the 66 enrolled RA patients, 24 developed new-onset HZ. Significantly lower MCP-1 levels were observed in patients with HZ compared to those without (median, 98.21 pg/mL, interquartile range (IQR) 77.63-150.30 pg/mL versus 142.3 pg/mL, IQR 106.7-175.6 pg/mL, p < 0.05). There was no significant difference in anti-IFN-γ titers, IFN-γ levels, or IP-10 levels between patients with and without HZ. Three of 24 patients with HZ had severe HZ with multi-dermatomal involvement. Anti-IFN-γ titers were significantly higher in patients with severe HZ than in those with non-severe HZ (median 24.8 ng/mL, IQR 21.0-38.2 ng/mL versus 10.5 ng/mL, IQR 9.9-15.0 ng/mL, p < 0.005). Our results suggest an association between reduced MCP-1 levels and HZ development in JAKi-treated RA patients. High-titer anti-IFN-γ autoantibodies may be related to severe HZ in these patients.

Efficacy of Bortezomib for Treating Anti-Interferon-Gamma Autoantibody-Associated Adult-Onset Immunodeficiency Syndrome

BACKGROUND

Currently, there is no effective treatment for adult-onset immunodeficiency (AOID) syndrome with anti-interferon-gamma autoantibodies (anti-IFN-γ-auto-Abs). This study aimed to investigate the effectiveness of bortezomib (BTZ) for decreasing anti-IFN-γ-auto-Abs.

METHODS

A pre- and post-intervention study was conducted from February 2017 through June 2019 at Siriraj Hospital (Bangkok, Thailand). Five patients were invited to receive once-weekly BTZ (1.3 mg/m2 body surface area) subcutaneously for 8 weeks followed by oral cyclophosphamide (1 mg/kg/d) for 4 months. The primary outcomes were the difference in antibody level at 8 and 48 weeks compared with baseline and the incidence of serious adverse events (AEs). The secondary outcome was the occurrence of opportunistic infections (OIs) during the 72 weeks after starting BTZ.

RESULTS

The median patient age was 46 years (range, 34-53). All patients had 3-5 OIs prior to enrollment. All patients were receiving antimycobacterial agents for treatment of nontuberculous mycobacterial infection at enrollment. There was no significant difference in the mean optical density of auto-Abs at 8 weeks (3.73 ± 0.72) or 48 weeks (3.74 ± 0.53) compared with baseline (3.84 ± 0.49; P = .336 and P = .555, respectively). However, after serum dilution, the antibody titer nonsignificantly decreased 8-16 weeks after BTZ initiation (P = .345). Ten OIs were observed 24-72 weeks after BTZ initiation.

CONCLUSIONS

Treatment with BTZ followed by cyclophosphamide yielded no significant decrease in antibody titer levels, and 10 OIs were observed during 24-72 weeks of BTZ treatment. No serious AEs were observed. Combining rituximab with BTZ is likely necessary to prevent generation of new autoantibody-producing plasma cells. Clinical Trials Registration. NCT03103555.

CXCL9 as a Reliable Biomarker for Discriminating Anti-IFN-γ-Autoantibody-Associated Lymphadenopathy that Mimics Lymphoma

The diagnosis of adult-onset immunodeficiency syndrome associated with neutralizing anti-interferon γ autoantibodies (AIGA) presents substantial challenges to clinicians and pathologists due to its nonspecific clinical presentation, absence of routine laboratory tests, and resemblance to certain lymphoma types, notably nodal T follicular helper cell lymphoma, angioimmunoblastic type (nTFHL-AI). Some patients undergo lymphadenectomy for histopathological examination to rule out lymphoma, even in the absence of a preceding clinical suspicion of AIGA. This study aimed to identify reliable methods to prevent misdiagnosis of AIGA in this scenario through a retrospective case-control analysis of clinical and pathological data, along with immune gene transcriptomes using the NanoString nCounter platform, to compare AIGA and nTFHL-AI. The investigation revealed a downregulation of the C-X-C motif chemokine ligand 9 (CXCL9) gene in AIGA, prompting an exploration of its diagnostic utility. Immunohistochemistry (IHC) targeting CXCL9 was performed on lymph node specimens to assess its potential as a diagnostic biomarker. The findings exhibited a significantly lower density of CXCL9-positive cells in AIGA compared to nTFHL-AI, displaying a high diagnostic accuracy of 92.3% sensitivity and 100% specificity. Furthermore, CXCL9 IHC demonstrated its ability to differentiate AIGA from various lymphomas sharing similar characteristics. In conclusion, CXCL9 IHC emerges as a robust biomarker for differentiating AIGA from nTFHL-AI and other similar conditions. This reliable diagnostic approach holds the potential to avert misdiagnosis of AIGA as lymphoma, providing timely and accurate diagnosis.

Cryptococcal meningitis

Cryptococcus neoformans and Cryptococcus gattii species complexes cause meningoencephalitis with high fatality rates and considerable morbidity, particularly in persons with deficient T cell-mediated immunity, most commonly affecting people living with HIV. Whereas the global incidence of HIV-associated cryptococcal meningitis (HIV-CM) has decreased over the past decade, cryptococcosis still accounts for one in five AIDS-related deaths globally due to the persistent burden of advanced HIV disease. Moreover, mortality remains high (~50%) in low-resource settings. The armamentarium to decrease cryptococcosis-associated mortality is expanding: cryptococcal antigen screening in the serum and pre-emptive azole therapy for cryptococcal antigenaemia are well established, whereas enhanced pre-emptive combination treatment regimens to improve survival of persons with cryptococcal antigenaemia are in clinical trials. Short courses (≤7 days) of amphotericin-based therapy combined with flucytosine are currently the preferred options for induction therapy of cryptococcal meningitis. Whether short-course induction regimens improve long-term morbidity such as depression, reduced neurocognitive performance and physical disability among survivors is the subject of further study. Here, we discuss underlying immunology, changing epidemiology, and updates on the management of cryptococcal meningitis with emphasis on HIV-associated disease.

Distinct Lymphocyte Immunophenotyping and Quantitative Anti-Interferon Gamma Autoantibodies in Taiwanese HIV-Negative Patients with Non-Tuberculous Mycobacterial Infections

PURPOSE

The presence of anti-interferon-γ autoantibodies (AutoAbs-IFN-γ) is not rare in patients suffering from persistent non-tuberculous mycobacterial (NTM) infections that are characteristic of adult-onset immunodeficiency syndrome. The immune disturbances in this distinct disorder remain to be elucidated.

METHODS

Patients with NTM infections but without effective response over 3 months' treatment were referred to our institute to quantify their level of AutoAbs-IFN-γ after excluding defective IL12/23-IFN-γ circuit and reactive oxygen species production. The AutoAbs-IFN-γ and percentage of lymphocyte subpopulations most relevant to T and B cell pools were assessed and compared with age-matched healthy controls.

RESULTS

A total of 31 patients were enrolled during the 15-year study period (2008-2022), 20 patients with > 50% suppression of IFN-γ detection at 1:100 serum dilution were classified into the Auto-NTM group. The remaining 11 with negligible suppression were assigned to the No Auto-NTM group. Mycobacterium chimaera-intracellulare group (MAC), M. kansasii, and M. abscessus were the most common pathogens. Pneumonia (19 vs 7), lymphadenitis (11 vs 5), Salmonella sepsis (6 vs 2), osteomyelitis (5 vs 1), and cutaneous herpes zoster (4 vs 4) were the main manifestations in both the Auto-NTM and No Auto-NTM groups who had similar onset-age (55.3 vs 53.6 years; p = 0.73) and follow-up duration (71.9 vs 54.6 months; p = 0.45). The Auto-NTM group had significantly higher transitional (IgM +  + CD38 + +), CD19 + CD21-low, and plasmablast (IgM-CD38 + +) in the B cell pool, with higher effector memory (CD4 + /CD8 + CD45RO + CCR7 -), senescent CD8 + CD57 + , and Th17 cells, but lower naïve (CD4 + /CD8 + CD45RO - CCR7 +) and Treg cells in the T cell pool when compared to the No Auto-NTM and healthy groups. NTM patients with/without AutoAbs-IFN-γ had lower Th1-like Tfh (CD4 + CXCR5 + CXCR3 + CCR6 -) cells. All Auto-NTM patients still had non-remitted mycobacterial infections and higher AutoAbs-IFN-γ despite anti-CD20 therapy in 3 patients.

CONCLUSION

In patients with suspected adult-onset immunodeficiency syndrome, two thirds (20/31) were recognized as having significantly inhibitory AutoAbs-IFN-γ with higher antibody-enhancing transitional, CD19 + CD21-low and plasmablast B cells; as well as higher effector memory, senescent CD8 + CD57 + and Th17 cells, but lower naïve T and Treg cells in contrast to those with negligible AutoAbs-IFN-γ. Such immunophenotyping disturbances might correlate with the presence of AutoAbs-IFN-γ. However, the mutual mechanisms need to be further clarified.

Disseminated nontuberculous mycobacterial infection with cryptic immunodeficiency mimicking malignancy: a case report

BACKGROUND

Nontuberculous mycobacteria (NTM) usually invades vulnerable hosts. Disseminated NTM (dNTM) infection can affect nearly all organs and be easily misdiagnosed as metastatic carcinoma or other systemic diseases, especially in seemingly immunocompetent hosts. Identification of underlying immunodeficiency is critical for the diagnosis and treatment of dNTM. Adult-onset immunodeficiency (AOID) with anti-IFN-γ autoantibodies has recently been recognized as a crucial but frequently neglected risk factor for dNTM infection. Frequent relapses of infection are common in AOID patients despite appropriate anti-infective treatment and B-cell-depleting therapy has shown some promising results. Herein, we report a case of dNTM infection mimicking malignancy in an AOID patient who was successfully treated with rituximab.

CASE PRESENTATION

A middle-aged male presented with fever, productive cough, multifocal skin abscesses and multiple osteolytic lesions with pathological fractures. Chest CT revealed consolidation of the lingula while bronchoscopy showed a mass completely blocking the airway opening of the inferior lingual segment. Metagenomic next-generation sequencing and mycobacterial culture of skin pus and bronchoalveolar lavage fluid reported Mycobacterium Colombiense, confirming the diagnosis of dNTM infection. However, anti-NTM antibiotics alone failed to prevent disease relapse and progression. Further evaluation indicated undetectable serum IFN-γ concentration and high-titer autoantibodies against IFN-γ, suggesting that AOID was the underlying reason for dNTM. Rituximab was added to treatment and successfully controlled the infection without relapse at one-year follow-up.

CONCLUSION

We reported a rare case of disseminated Mycobacterium Colombiense infection manifested with pulmonary mass, pathological fracture and dermapostasis in a host with AOID. Our case demonstrated that AOID should be screened when patients get the episode of disseminated NTM infection particularly when other risk factors are excluded. Besides prolonged anti-NTM therapy, AOID-associated NTM infection should be treated with B-cell-depleting therapy to prevent recurrence.

Disseminated Mycobacterium chimaera infection in a patient with adult-onset immunodeficiency syndrome: case report

BACKGROUND

Patients with adult-onset immunodeficiency syndrome due to anti-interferon-γ autoantibodies (AIGAs) are susceptible to disseminated Mycobacterium avium complex (MAC) infections. M. chimaera, a newly identified MAC species, is distinguished from the others due to the reduced virulence. Previous cases of disseminated M. chimaera infection have been linked to cardiothoracic surgery. Reports of disseminated M. chimaera in patients without a history of cardiothoracic surgery are rare.

CASE PRESENTATION

A 57-year-old Asian man, previously healthy, presented with fever, dry cough, exertional dyspnea, and decreased appetite. The delayed resolution of pneumonia despite antibiotic treatment prompted further imaging studies and biopsies from the lung and lymph node. The fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) demonstrated intense uptake in lung consolidations and diffuse lymphadenopathy. Cultures of the specimens obtained from sputum, blood, stool, lung tissue, and lymph node grew M. chimaera. Further immunological evaluation disclosed the presence of neutralizing AIGAs, which possibly led to acquired immunodeficiency and disseminated M. chimaera infection.

CONCLUSIONS

We herein present the first case of adult-onset immunodeficiency due to AIGAs complicated with disseminated M. chimaera infection. Further immunological evaluation, including AIGAs, may be warranted in otherwise healthy patients who present with disseminated mycobacterial infection.

Periocular Infection of Mycobacterium avium Complex in a Patient with Interferon-γ Autoantibodies: A Case Report

The neutralizing anti-interferon-γ autoantibody (nAIGA)-associated immunodeficiency is an emerging entity frequently associated with the nontuberculosis mycobacterium (NTM) infection and other opportunistic infections. We present a female patient with a mysterious periocular Mycobacterium avium complex (MAC) infection, accompanied by sequential opportunistic infections including Salmollelosis and herpes zoster infection. Her condition stabilized after long-term antimycobacterial treatment. Nevertheless, neutralizing anti-interferon-γ autoantibody was found in her serum, which was compatible with the scenario of adult-onset immunodeficiency.

Anticytokine autoantibodies: Autoimmunity trespassing on antimicrobial immunity

Anticytokine autoantibodies can cause immunodeficiency or dysregulate immune responses. They may phenocopy genetically defined primary immunodeficiencies. We review current anti-type 1 and anti-type 2 interferon; anti-IL-12/23, anti-IL-17, and anti-GM-CSF autoantibodies; HLA associations; disease associations; and mechanistically based treatment options. Suspecting the presence of these autoantibodies in patients and identifying them at the onset of symptoms should ameliorate disease and improve outcomes.

Pathological humerus fracture due to anti-interferon-gamma autoantibodies: A case report

BACKGROUND

Various etiologies contribute to pathological fractures, including bone infections. Recently, non-tuberculosis Mycobacterium-related bone infections among patients with anti-interferon-gamma autoantibody-induced adult-onset immunodeficiency has raised concerns in Southeast Asia, with the common presentations including osteomyelitis. However, it also rarely manifests as traumatic fractures, as reported in this case.

CASE SUMMARY

A diabetic female fractured her humerus after a traumatic accident and received fixation surgery. Abnormal necrotic bone tissue and abscess formation were noted, and she was diagnosed with a pathological fracture due to non-tuberculosis Mycobacterium infection. Multiple bone involvement was also revealed in a bone scan. Anti-interferon-gamma autoantibodies were then checked due to an unexplained immunocompromised status and found to be positive. Her humerus fracture and multiple bone infections healed after steroid and anti-non-tuberculosis Mycobacterium medication treatment following fixation surgery.

CONCLUSION

Comprehensive preoperative evaluations may help identify pathological fractures and guide the treatment course.

Neutralizing anti-GM-CSF autoantibodies in patients with CNS and localized cryptococcosis: a longitudinal follow-up and literature review

BACKGROUND

Neutralizing anti-GM-CSF autoantibodies (AAbs) have been increasingly recognized to predispose healthy individuals to disseminated cryptococcosis. However, studies have only considered patients with central nervous system (CNS) infection. No longitudinal study has captured the disease spectrum and clinical course.

METHODS

We prospectively enrolled adults without human immunodeficiency virus infection who had disseminated or unusual cryptococcosis. We compared the demographics, clinical features, kinetics of serum cryptococcal antigen (CrAg) titers, anti-GM-CSF AAb concentrations, and treatment outcomes between patients with (case patients) and without (control patients) anti-GM-CSF AAbs. Additional reports from the literature were also reviewed.

RESULTS

Twenty-three patients were enrolled, of whom 6 tested positive for anti-GM-CSF AAbs. All case patients with positive fungal cultures (5/5, 100%) were infected with Cryptococcus gattii VGII. Among them, 3 had exclusively pulmonary involvement, and 1 had only musculoskeletal lesions. Patients with CNS cryptococcosis exhibited a higher serum concentration of anti-GM-CSF AAb than those with extraneural cryptococcosis. Case patients had higher initial and peak levels of serum CrAg and longer duration of antigenemia compared with the control patients. All case patients who had completed antifungal therapy had favorable outcomes without recurrence.

CONCLUSIONS

Testing for anti-GM-CSF AAbs should be considered for not only previously healthy patients with disseminated cryptococcosis but also those with unexplained, localized cryptococcosis. Recurrence after completion of antifungal therapy was rare despite the persistence of anti-GM-CSF AAbs.

Lymphadenopathy Associated With Neutralizing Anti-interferon-gamma Autoantibodies Could Have Monoclonal T-cell Proliferation Indistinguishable From Malignant Lymphoma and Treatable by Antibiotics: A Clinicopathologic Study

Early recognition of adult-onset immunodeficiency associated with neutralizing anti-interferon gamma autoantibodies (anti-IFNγ Abs) remains difficult, and misdiagnoses have been reported. Although febrile lymphadenopathy is among the most common initial manifestations of this disorder, no comprehensive clinicopathologic analysis of lymphadenopathy in patients with anti-IFNγ Abs has been reported. Here, we describe 26 lymph node biopsy specimens from 16 patients. All patients exhibited concurrent disseminated nontuberculous mycobacterial infections, and 31% received a tentative diagnosis of lymphoma at initial presentation. We found 3 distinct histomorphologic patterns: well-formed granuloma (46%), suppurative inflammation or loose histiocytic aggregates (31%), and lymphoproliferative disorder (LPD, 23%). The latter shared some of the features of malignant T-cell lymphoma, IgG4-related disease, and multicentric Castleman disease. Half of the specimens with LPD had monoclonal T cells, and 33.3% were indistinguishable from angioimmunoblastic T-cell lymphoma as per current diagnostic criteria. All lymphadenopathy with LPD features regressed with antibiotics without administration of cytotoxic chemotherapy or immunotherapy. The median follow-up time was 4.3 years. Our study highlights the substantial challenge of distinguishing between lymphoma and other benign lymphadenopathy in the setting of neutralizing anti-IFNγ Abs. Increased vigilance and multidisciplinary discussion among clinicians and pathologists are required to achieve the most appropriate diagnosis and management.

Anti-interferon-γ autoantibody-associated immunodeficiency

Anticytokine autoantibodies are an emerging disease etiology, through the disturbance of physiological functions of cognate cytokines. Anti-interferon (IFN)-γ autoantibodies (AIGAs) were first identified in patients with severe mycobacterial infections, and were considered to be an autoimmune phenocopy of inborn genetic errors of the IL-12/IFN-γ axis. More than 600 reported cases, most originating from Southeast Asia, have been diagnosed over the last decade. Specific HLA class II molecules are associated with these autoantibodies, which provide a genetic basis for the high prevalence of this immunodeficiency syndrome in certain ethnic groups. Salmonellosis and herpes zoster reactivation are observed in more than half the patients with AIGAs. Moreover, AIGAs have been shown to underlie severe Taralomyce marneffei infection in HIV-negative patients. AIGAs may, thus, be considered a new form of late-onset immunodeficiency conferring a predisposition not only to severe mycobacterial, but also to some bacterial and fungal infections.

Autoantibodies against cytokines: phenocopies of primary immunodeficiencies?

Anti-cytokine autoantibodies may cause immunodeficiency and have been recently recognized as ‘autoimmune phenocopies of primary immunodeficiencies’ and are found in particular, but not exclusively in adult patients. By blocking the cytokine’s biological function, patients with anti-cytokine autoantibodies may present with a similar clinical phenotype as the related inborn genetic disorders. So far, autoantibodies to interferon (IFN)-γ, GM-CSF, to a group of TH-17 cytokines and to IL-6 have been found to be causative or closely associated with susceptibility to infection. This review compares infectious diseases associated with anti-cytokine autoantibodies with primary immunodeficiencies affecting similar cytokines or related pathways.