Clinical manifestations, course, and outcome of patients with neutralizing anti-interferon-γ autoantibodies and disseminated nontuberculous mycobacterial infections

The ouroboros of autoimmunity

Human autoimmunity against elements conferring protective immunity can be symbolized by the 'ouroboros', a snake eating its own tail. Underlying infection is autoimmunity against three immunological targets: neutrophils, complement and cytokines. Autoantibodies against neutrophils can cause peripheral neutropenia underlying mild pyogenic bacterial infections. The pathogenic contribution of autoantibodies against molecules of the complement system is often unclear, but autoantibodies specific for C3 convertase can enhance its activity, lowering complement levels and underlying severe bacterial infections. Autoantibodies neutralizing granulocyte-macrophage colony-stimulating factor impair alveolar macrophages, thereby underlying pulmonary proteinosis and airborne infections, type I interferon viral diseases, type II interferon intra-macrophagic infections, interleukin-6 pyogenic bacterial diseases and interleukin-17A/F mucocutaneous candidiasis. Each of these five cytokine autoantibodies underlies a specific range of infectious diseases, phenocopying infections that occur in patients with the corresponding inborn errors. In this Review, we analyze this ouroboros of immunity against immunity and posit that it should be considered as a factor in patients with unexplained infection.

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.

Neutralizing IFN-γ autoantibodies are rare and pathogenic in HLA-DRB1*15:02 or 16:02 individuals

BACKGROUNDWeakly virulent environmental mycobacteria (EM) can cause severe disease in HLA-DRB1*15:02 or 16:02 adults harboring neutralizing anti-IFN-γ autoantibodies (nAIGAs). The overall prevalence of nAIGAs in the general population is unknown, as are the penetrance of nAIGAs in HLA-DRB1*15:02 or 16:02 individuals and the proportion of patients with unexplained, adult-onset EM infections carrying nAIGAs.METHODSThis study analyzed the detection and neutralization of anti-IFN-γ autoantibodies (auto-Abs) from 8,430 healthy individuals of the general population, 257 HLA-DRB1*15:02 or 16:02 carriers, 1,063 patients with autoimmune disease, and 497 patients with unexplained severe disease due to EM.RESULTSWe found that anti-IFN-γ auto-Abs detected in 4,148 of 8,430 healthy individuals (49.2%) from the general population of an unknown HLA-DRB1 genotype were not neutralizing. Moreover, we did not find nAIGAs in 257 individuals carrying HLA-DRB1* 15:02 or 16:02. Additionally, nAIGAs were absent in 1,063 patients with an autoimmune disease. Finally, 7 of 497 patients (1.4%) with unexplained severe disease due to EM harbored nAIGAs.CONCLUSIONThese findings suggest that nAIGAs are isolated and that their penetrance in HLA-DRB1*15:02 or 16:02 individuals is low, implying that they may be triggered by rare germline or somatic variants. In contrast, the risk of mycobacterial disease in patients with nAIGAs is high, confirming that these nAIGAs are the cause of EM disease.FUNDINGThe Laboratory of Human Genetics of Infectious Diseases is supported by the Howard Hughes Medical Institute, the Rockefeller University, the St. Giles Foundation, the National Institutes of Health (NIH) (R01AI095983 and U19AIN1625568), the National Center for Advancing Translational Sciences (NCATS), the NIH Clinical and Translational Science Award (CTSA) program (UL1 TR001866), the French National Research Agency (ANR) under the "Investments for the Future" program (ANR-10-IAHU-01), the Integrative Biology of Emerging Infectious Diseases Laboratory of Excellence (ANR-10-LABX-62-IBEID), ANR-GENMSMD (ANR-16-CE17-0005-01), ANR-MAFMACRO (ANR-22-CE92-0008), ANRSECTZ170784, the French Foundation for Medical Research (FRM) (EQU201903007798), the ANRS-COV05, ANR GENVIR (ANR-20-CE93-003), and ANR AI2D (ANR-22-CE15-0046) projects, the ANR-RHU program (ANR-21-RHUS-08-COVIFERON), the European Union's Horizon 2020 research and innovation program under grant agreement no. 824110 (EASI-genomics), the Square Foundation, Grandir - Fonds de solidarité pour l'enfance, the Fondation du Souffle, the SCOR Corporate Foundation for Science, the Battersea & Bowery Advisory Group, William E. Ford, General Atlantic's Chairman and Chief Executive Officer, Gabriel Caillaux, General Atlantic's Co-President, Managing Director, and Head of business in EMEA, and the General Atlantic Foundation, Institut National de la Santé et de la Recherche Médicale (INSERM) and of Paris Cité University. JR was supported by the INSERM PhD program for doctors of pharmacy (poste d'accueil INSERM). JR and TLV were supported by the Bettencourt-Schueller Foundation and the MD-PhD program of the Imagine Institute. MO was supported by the David Rockefeller Graduate Program, the Funai Foundation for Information Technology (FFIT), the Honjo International Scholarship Foundation (HISF), and the New York Hideyo Noguchi Memorial Society (HNMS).

Anti-cytokine autoantibodies: mechanistic insights and disease associations

Anti-cytokine autoantibodies (ACAAs) are increasingly recognized as modulating disease severity in infection, inflammation and autoimmunity. By reducing or augmenting cytokine signalling pathways or by altering the half-life of cytokines in the circulation, ACAAs can be either pathogenic or disease ameliorating. The origins of ACAAs remain unclear. Here, we focus on the most common ACAAs in the context of disease groups with similar characteristics. We review the emerging genetic and environmental factors that are thought to drive their production. We also describe how the profiling of ACAAs should be considered for the early diagnosis, active monitoring, treatment or sub-phenotyping of diseases. Finally, we discuss how understanding the biology of naturally occurring ACAAs can guide therapeutic strategies.

Anticytokine Autoantibodies in Infectious Diseases: A Practical Overview

Anticytokine autoantibodies (ACAAs) are a fascinating group of antibodies that have gained more and more attention in the field of autoimmunity and secondary immunodeficiencies over the years. Some of these antibodies are characterized by their ability to target and neutralize specific cytokines. ACAAs can play a role in the susceptibility to several infectious diseases, and their infectious manifestations depending on which specific immunological pathway is affected. In this review, we will give an outline per infection in which ACAAs might play a role and whether additional immunomodulatory treatment next to antimicrobial treatment can be considered. Finally, we describe the areas for future research on ACAAs.

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.

Disseminated coinfection with Mycobacterium Avium complex and Mycobacterium Kansasii in a patient with idiopathic CD4+ lymphocytopenia: A case report

Simultaneously disseminated coinfection with two species of nontuberculous mycobacteria (NTM) is extremely rare and had been reported only in immunocompromised individuals. Here, we report a 59-year-old Thai man, previously healthy. He presented with a 2-month history of prolonged fever, constitutional symptoms, and hepatosplenomegaly. His chest and abdomen computed tomography illustrated multiple enlarged mediastinal lymph nodes accompanied with multifocal crazy-paving appearance in both lungs and hepatosplenomegaly. Endobronchial ultrasound-guided transbronchial needle aspiration was performed on the mediastinal nodes. The pathologic findings were necrotizing granulomatous lymphadenitis with numerous AFB-positive bacilli. Blood culture subsequently isolated M. intracellulare, while BAL and lymph node culture isolated M. intracellulare and M. kansasii, which confirmed species by multiplex PCR and 16s rRNA sequencing. Idiopathic CD4+ lymphocytopenia (ICL) was diagnosed as the cause of secondary immune deficiency. Intravenous imipenem, amikacin, and azithromycin were administered as an empirical antibiotic regimen for 4 weeks, then substituted to oral rifampicin, clarithromycin, moxifloxacin, and ethambutol as definitive regimen. Unfortunately, it was found that he had died unexpectedly at home after 4 months of treatment, possibly related to this illness. In our view, patients with severe disseminated NTM disease should be evaluated to explore a secondary immune deficiency disorder. An ICL is a rare heterogenous syndrome but should be considered.

Clinical characteristics of tracheobronchial Talaromyces marneffei infection in non-HIV-infected patients in South China

OBJECTIVES

Tracheobronchial Talaromyces marneffei (T. marneffei) infections among non-HIV-infected patients are rare. To improve understanding, we analysed the clinical features, immune mechanisms, treatment, and prognosis.

METHODS

Data on hospitalized patients with tracheobronchial T. marneffei infections from September 2013 to May 2022 were collected. The clinical and imaging features were analysed.

RESULTS

Nineteen patients were enrolled, with a median age of 52 years (45-62 years). The most common symptoms were cough, expectoration, fever, weight loss, and anaemia. The total white blood cell and neutrophil counts, erythrocyte sedimentation rate, C-reactive protein, procalcitonin and globulin were increased, and the serum albumin levels were decreased. Chest CT manifestations included patchy shadows, masses, obstructive atelectasis, cavities, pleural effusion, and hilar and mediastinal lymphadenopathy. The fibreoptic bronchoscopy findings included masses, polyps or nodules with mucosal oedema, hypertrophic bulges, lumen stenosis or obstruction, and purulent secretions. T. marneffei infection was confirmed in 10 patients by positive culture, in five by both culture and metagenomic next-generation sequencing (mNGS), in two by mNGS, in one by culture and pathology and in 1 by histopathology. BALF (15/19, 78.9%) had the highest culture positive rate, followed by sputum (3/19), bronchial mucosa (1/1), lung biopsy (1/2); 36.8% of the patients were coinfected with other pathogens. For induction therapy, 7, 6, 2, and 4 patients received voriconazole, amphotericin B, voriconazole combined with amphotericin B, and fluconazole therapy, respectively, and 26.3% received treatment combined with nebulization and/or administration of amphotericin B under fibreoptic bronchoscopy. Four patients were treated for underlying diseases or coinfection, 31.6% were cured, 42.1% improved, and 26.3% died.

CONCLUSIONS

T. marneffei infection is common in the tracheobronchial airway tissue or secretions, and bronchoscopy has important diagnostic and treatment value. Antifungal therapy, including systemic therapy, involves triazoles and amphotericin administration, and aerosol inhalation and administration of amphotericin B under bronchoscopy are important.

Health related quality of life in anti interferon γ autoantibody associated immunodeficiency syndrome measured with EQ5D5L and SF36

The anti-IFN-γ disease is a rare condition characterized by recurrent and persistent infections, potentially impacting the quality of life (QoL). However, comprehensive data on QoL in this population are lacking. This study aims to evaluate the QoL of Anti-IFN-γ patients compared to healthy control and explore potential differences in QoL between patients in the active and remission stages. A cross-sectional study design was conducted, recruiting 38 Anti-IFN-γ patients and 38 sex- and age-matched healthy controls. QoL assessment utilized the 5-level EuroQol-5 Dimension (EQ-5D-5L) and the 36-Item Short Form Health Survey (SF-36). The Anti-IFN-γ group had a mean age of 57.37 (± 10.32) years, with females comprising 60.53%. Among the Anti-IFN-γ patients, 55.26% were classified as having active disease. 63% of Anti-IFN-γ patients received Immunosuppressive treatments. Anti-IFN-γ disease exhibited a significant negative impact on HRQoL, as evidenced by lower utility scores in EQ-5D-5L and lower physical and mental component scores in SF-36 across various domains, including physical function, role physical, general health, bodily pain, social functioning, role emotion and mental health, compared to healthy controls. Additionally, patients in the active disease displayed lower scores in multiple domains, including bodily pain, general health, role emotion and mental health, and a lower utility score in EQ-5D-5L compared to patients in remission. The anti-IFN-γ disease significantly impairs the HRQoL of affected individuals compared to healthy controls. However, effective treatment leading to remission holds promise for improving the HRQoL of patients with Anti-IFN-γ disease.

Immunodeficiency due to a novel variant in PIK3CD: a case report

BACKGROUND

Primary immunodeficiencies are immunological disorders caused by gene mutations involved in immune system development and activation. Recently, activated phosphoinositide 3-kinase delta syndrome (APDS) due to mutations in the phosphoinositide 3-kinase (PI3K), phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit delta gene (PIK3CD), and phosphoinositide 3-kinase regulatory subunit 1 (PIK3R1) genes have been reported to induce a combined immunodeficiency syndrome leading to senescent T cells, lymphadenopathy, and immunodeficiency. The exact diagnosis of these deficiencies is essential for treatment and prognosis. In recent years, targeted treatment with selective PI3Kd inhibitors has had a significant effect on controlling the symptoms of these patients.

CASE PRESENTATION

In this case report, we represent a 27-month-old girl with recurrent fever, an increased level of inflammatory markers, and erythema nodosum, who was referred to the rheumatology clinic. In the course of evaluations, because of the lack of clinical improvement with usual treatments, and a history of frequent respiratory infections, combined immunodeficiency was diagnosed in the immunological investigations. Moreover, whole-exome sequencing was performed for her.

CONCLUSION

The genetic analysis found a novel variant of PIK3CD (c.1429 G > A) in the patient. Following daily antibiotic prophylaxis and monthly IV therapy, the patient's frequent infections and fevers were controlled.

An Overlooked and Underrated Endemic Mycosis-Talaromycosis and the Pathogenic Fungus Talaromyces marneffei

Talaromycosis is an invasive mycosis endemic in tropical and subtropical Asia and is caused by the pathogenic fungus Talaromyces marneffei. Approximately 17,300 cases of T. marneffei infection are diagnosed annually, and the reported mortality rate is extremely high (~1/3). Despite the devastating impact of talaromycosis on immunocompromised individuals, particularly HIV-positive persons, and the increase in reported occurrences in HIV-uninfected persons, diagnostic and therapeutic approaches for talaromycosis have received far too little attention worldwide. In 2021, scientists living in countries where talaromycosis is endemic raised a global demand for it to be recognized as a neglected tropical disease. Therefore, T. marneffei and the infectious disease induced by this fungus must be treated with concern. T. marneffei is a thermally dimorphic saprophytic fungus with a complicated mycological growth process that may produce various cell types in its life cycle, including conidia, hyphae, and yeast, all of which are associated with its pathogenicity. However, understanding of the pathogenic mechanism of T. marneffei has been limited until recently. To achieve a holistic view of T. marneffei and talaromycosis, the current knowledge about talaromycosis and research breakthroughs regarding T. marneffei growth biology are discussed in this review, along with the interaction of the fungus with environmental stimuli and the host immune response to fungal infection. Importantly, the future research directions required for understanding this serious infection and its causative pathogenic fungus are also emphasized to identify solutions that will alleviate the suffering of susceptible individuals worldwide.

The detectable anti-interferon-γ autoantibodies in COVID-19 patients may be associated with disease severity

BACKGROUND

Neutralizing anti-interferon (IFN)-γ autoantibodies are linked to adult-onset immunodeficiency and opportunistic infections.

METHODS

To explore whether anti-IFN-γ autoantibodies are associated with disease severity of coronavirus disease 2019 (COVID-19), we examined the titers and functional neutralization of anti-IFN-γ autoantibodies in COVID-19 patients. In 127 COVID-19 patients and 22 healthy controls, serum titers of anti-IFN-γ autoantibodies were quantified using enzyme-linked immunosorbent assay, and the presence of autoantibodies was verified with immunoblotting assay. The neutralizing capacity against IFN-γ was evaluated with flow cytometry analysis and immunoblotting, and serum cytokines levels were determined using the MULTIPLEX platform.

RESULTS

A higher proportion of severe/critical COVID-19 patients had positivity for anti-IFN-γ autoantibodies (18.0%) compared with non-severe patients (3.4%, p < 0.01) or healthy control (HC) (0.0%, p < 0.05). Severe/critical COVID-19 patients also had higher median titers of anti-IFN-γ autoantibodies (5.01) compared with non-severe patients (1.33) or HC (0.44). The immunoblotting assay could verify the detectable anti-IFN-γ autoantibodies and revealed more effective inhibition of signal transducer and activator of transcription (STAT1) phosphorylation on THP-1 cells treated with serum samples from anti-IFN-γ autoantibodies-positive patients compared with those from HC (2.21 ± 0.33 versus 4.47 ± 1.64, p < 0.05). In flow-cytometry analysis, sera from autoantibodies-positive patients could also significantly more effectively suppress the STAT1 phosphorylation (median,67.28%, interquartile range [IQR] 55.2-78.0%) compared with serum from HC (median,106.7%, IQR 100.0-117.8%, p < 0.05) or autoantibodies-negative patients (median,105.9%, IQR 85.5-116.3%, p < 0.05). Multivariate analysis revealed that the positivity and titers of anti-IFN-γ autoantibodies were significant predictors of severe/critical COVID-19. Compared with non-severe COVID-19 patients, we reveal that a significantly higher proportion of severe/critical COVID-19 patients are positive for anti-IFN-γ autoantibodies with neutralizing capacity.

CONCLUSION

Our results would add COVID-19 to the list of diseases with the presence of neutralizing anti-IFN-γ autoAbs. Anti-IFN-γ autoantibodies positivity is a potential predictor of severe/critical COVID-19.

Diagnostic and Therapeutic Challenges in Disseminated Mycobacterium colombiense Infection Caused by Interferon-γ Neutralizing Autoantibodies

Adult-onset immunodeficiency due to interferon-γ-neutralizing autoantibodies (nIFNγ-autoAbs) can remain underdiagnosed. We present a case of severe Mycobacterium colombiense infection with nIFNγ-autoAbs. To ensure early diagnosis, clinicians should have a high index of suspicion in patients of Asian descent with opportunistic infections and perform QuantiFERON-TB assay for disease screening.

High-titer anti-interferon-γ neutralizing autoantibodies linked to opportunistic infections in patients with adult-onset still's disease

Objective

Neutralizing anti-interferon (IFN)-γ autoantibodies are linked to opportunistic infections (OIs). To explore the association between anti-IFN-γ autoantibodies and OIs in patients with adult-onset Still's disease (AOSD), we aimed to examine the ability of these autoantibodies to blockade signal transducer and activator of transcription (STAT1)-phosphorylation and chemokines production.

Methods

Serum titers of anti-IFN-γ autoantibodies were quantified using ELISA in 29 AOSD and 22 healthy controls (HC). The detectable autoantibodies were verified with immunoblotting assay, and their neutralizing capacity against IFN-γ-signaling was evaluated with flow-cytometry analysis and immunoblotting. IFN-γ-mediated production of supernatant chemokines, including monocyte chemoattractant protein-1 (MCP-1) and IFN-γ inducible protein-10 (IP-10), were measured by ELISA.

Results

Among 29 AOSD patients, high titers of anti-IFN-γ neutralizing autoantibodies were detectable in two patients with OIs. Immunoblotting assay revealed more effective inhibition of STAT1-phosphorylation in THP-1 cells treated with sera from autoantibody-positive AOSD patients (56.7 ± 34.79%) compared with those from HC (104.3 ±29.51%), which was also demonstrated in flow-cytometry analysis (47.13 ± 40.99 vs. 97.92 ± 9.48%, p < 0.05). Depleted serum IgG from anti-IFN-γ autoAbs-positive AOSD patients with OIs restored phosphorylated STAT-1 upon IFN-γ treatment. Sera from autoantibody-positive AOSD patients more effectively inhibited IFN-γ-mediated production of MCP-1 (45.65 pg/ml) and IP-10 (22.44 pg/ml) than sera from HC (263.1 pg/ml and 104.0 pg/ml, both p < 0.05). Serum samples showing the strongest inhibition of IFN-γ-signaling were from two patients with high-titer autoantibodies and OIs.

Conclusion

AOSD patients have a high positive rate and titers of anti-IFN-γ autoantibodies. The remarkable blockade effect of high-titer autoantibodies on IFN-γ-mediated STAT1-phosphorylation and chemokines could make these patients susceptible to OIs.

Intravenous Cyclophosphamide Therapy for Anti-IFN-γ Autoantibody-Associated Talaromyces marneffei Infection

High titers of anti-interferon-γ autoantibodies (AIGAs) are an important factor leading to persistent, relapsed, and refractory infections in HIV-negative hosts infected with Talaromyces marneffei (TM). We report 5 patients treated with pulses of high-dose intravenous cyclophosphamide (IVCY) who were followed for 2 years. Before IVCY therapy, all patients had multiple relapses, with a median (interquartile range [IQR]) of 2 (1-3) instances of relapse. The median serum AIGA titers (IQR) were 58 753 (41 203-89 605) ng/mL at diagnosis, 48 189.4 (15 537-83 375) ng/mL before IVCY therapy, and 10 721.2 (5637-13 245) ng/mL at the end of IVCY therapy (P < .05). After 3 months of follow-up, the median AIGA titers (IQR) rose gradually to 21 232.6 (9896-45 626) ng/mL, and to 37 464.2 (19 872-58 321) ng/mL at 24 months (P < .05). Five patients discontinued antimicrobial therapy within 3-12 months after completion of IVCY therapy, but only 1 patient had a relapse. In conclusion, pulses of short-term and high-dose IVCY can effectively reduce AIGA titers.

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.

A case of mediastinal abscess and infected aortic aneurysm caused by dissemination of Mycobacterium abscessus subsp. massiliense pulmonary disease

An 81-year-old man was admitted to our hospital because of fever and malaise that had persisted for 3 months. The patient had undergone two aortic valve replacements, 10 and 5 years previously, because of aortic valve regurgitation and infectious endocarditis. He also had had asymptomatic Mycobacterium abscessus complex (MABC) pulmonary disease for the two previous years. Contrast-enhanced computed tomography showed a mediastinal abscess and an ascending aortic aneurysm. Mycobacterium abscessus subsp. massiliense was cultured from his blood, suggesting the aortic aneurysm was secondary to infection of an implanted device. After enlargement over only a few days, a leakage of contrast medium to the mediastinal abscess was found on computed tomography. The patient was diagnosed with rupture of an infectious aortic aneurysm, and emergency aortic replacement and drainage of the mediastinal abscess were successful. The patient was treated with several antibiotics, including meropenem, amikacin, and clarithromycin, and his general condition improved. Cultures from both the mediastinal abscess and a pericardial patch that was placed at the time of surgery 5 years previously revealed MABC. In our case, the infected aortic aneurysm most likely resulted from MABC pulmonary disease rather than from previous intraoperative contamination. This route of infection is rare. Physicians should be aware of the possibility of dissemination and subsequent infection of implants related to MABC pulmonary disease.

Rapid diagnosis of Talaromyces marneffei infection by metagenomic next-generation sequencing technology in a Chinese cohort of inborn errors of immunity

Talaromyces marneffei (T. marneffei) is an opportunistic pathogen. Patients with inborn errors of immunity (IEI) have been increasingly diagnosed with T. marneffei in recent years. The disseminated infection of T. marneffei can be life-threatening without timely and effective antifungal therapy. Rapid and accurate pathogenic microbiological diagnosis is particularly critical for these patients. A total of 505 patients with IEI were admitted to our hospital between January 2019 and June 2022, among whom T. marneffei was detected in 6 patients by metagenomic next-generation sequencing (mNGS), and their clinical and immunological characteristics were summarized. We performed a systematic literature review on T. marneffei infections with published immunodeficiency-related gene mutations. All patients in our cohort were confirmed to have genetic mutations in IL12RB1, IFNGR1, STAT1, STAT3, and CD40LG. T. marneffei was detected in both the blood and lymph nodes of P1 with IL12RB1 mutations, and the clinical manifestations were serious and included recurrent fever, weight loss, severe anemia, splenomegaly and lymphadenopathy, all requiring long-term antifungal therapy. These six patients received antifungal treatment, which relieved symptoms and improved imaging findings. Five patients survived, while one patient died of sepsis after hematopoietic stem cell transplantation. The application of mNGS methods for pathogen detection in IEI patients and comparison with traditional diagnosis methods were investigated. Traditional diagnostic methods and mNGS tests were performed simultaneously in 232 patients with IEI. Compared to the traditional methods, the sensitivity and specificity of mNGS in diagnosing T. marneffei infection were 100% and 98.7%, respectively. The reporting time for T. marneffei detection was approximately 26 hours by mNGS, 3-14 days by culture, and 6-11 days by histopathology. T. marneffei infection was first reported in IEI patients with IL12RB1 gene mutation, which expanded the IEI lineage susceptible to T. marneffei. For IEI patients with T. marneffei infection, we highlight the application of mNGS in pathogenic detection. mNGS is recommended as a front-line diagnostic test for rapidly identifying pathogens in complex and severe infections.

Cryptococcus gattii Infection as the Major Clinical Manifestation in Patients with Autoantibodies Against Granulocyte-Macrophage Colony-Stimulating Factor

PURPOSE

Anti-granulocyte-macrophage colony-stimulating factor autoantibodies (anti-GM-CSF Abs) are a predisposing factor for pulmonary alveolar proteinosis (PAP) and Cryptococcus gattii cryptococcosis. This study aimed to investigate clinical manifestations in anti-GM-CSF Ab-positive patients with C. gattii cryptococcosis and analyze the properties of anti-GM-CSF Abs derived from these patients and patients with PAP.

METHODS

Thirty-nine patients diagnosed with cryptococcosis (caused by C. neoformans or C. gattii) and 6 with PAP were enrolled in the present study. Clinical information was obtained from medical records. Blood samples were collected for analysis of autoantibody properties. We also explored the National Health Insurance Research Database (NHIRD) of Taiwan to investigate the epidemiology of cryptococcosis and PAP.

RESULTS

High titers of neutralizing anti-GM-CSF Abs were identified in 15 patients with cryptococcosis (15/39, 38.5%). Most anti-GM-CSF Ab-positive cryptococcosis cases had central nervous system (CNS) involvement (14/15, 93.3%). Eleven out of 14 (78.6%) anti-GM-CSF Ab-positive CNS cryptococcosis patients were confirmed to be infected with C. gattii, and PAP did not occur synchronously or metachronously in a single patient from our cohort. Exploration of an association between HLA and anti-GM-CSF Ab positivity or differential properties of autoantibodies from cryptococcosis patients and PAP yielded no significant results.

CONCLUSION

Anti-GM-CSF Abs can cause two diseases, C. gattii cryptococcosis and PAP, which seldom occur in the same subject. Current biological evidence regarding the properties of anti-GM-CSF Abs cannot provide clues regarding decisive mechanisms. Further analysis, including more extensive cohort studies and investigations into detailed properties, is mandatory to better understand the pathogenesis of anti-GM-CSF Abs.

Development of intravascular large B-cell lymphoma during prophylactic antibiotic treatment for anti-interferon-gamma autoantibody syndrome: A case report

Anti-interferon (IFN)-γ autoantibody-positive syndrome is one of the acquired non-HIV cellular immunodeficiencies, caused by abnormalities in the IFN-γ/interleukin (IL)-12 pathways. It is often diagnosed alongside the onset of disseminated mycobacterium infection, and requires continuous antimycobacterial chemotherapy; however, the detailed pathological mechanisms underlying this syndrome, including its prognosis, are not known. To the best of our knowledge, this is the first reported case of intravascular large B-cell lymphoma complicated by anti-IFN-γ autoantibody syndrome, presented in an 82-year-old woman. The patient had been diagnosed with anti-IFN-γ autoantibody immunodeficiency ten years ago. She had repeated subacute fever of undetermined origin for 13 months that made us suspect infections, such as disseminated mycobacterium disease and other viral and fungal infections, despite receiving prophylactic antimycobacterial chemotherapy with rifampicin and clarithromycin. However, all the screenings performed showed no evidence of infectious diseases; thus, she was finally diagnosed with intravascular large B-cell lymphoma via a random skin biopsy. Unfortunately, the patient debilitated rapidly and died. Evidence supporting a correlation between anti-IFN-γ autoantibody syndrome and carcinogenesis is still lacking, although it is known that patients with anti-IFN-γ autoantibody syndrome are at risk of persistent viral infection-related and T-cell lineage-related carcinogenesis. This case demonstrated that patients with anti-IFN-γ autoantibody syndrome are also at risk of developing B-cell lymphoma, such as intravascular lymphoma. This emphasizes that caution should be paid to increased risk of developing malignancy during the long-term management of anti-IFN-γ autoantibody syndrome with cellular immunodeficiency.

Chronic Granulomatous Disease-Like Presentation of a Child with Autosomal Recessive PKCδ Deficiency

BACKGROUND

Autosomal recessive (AR) PKCδ deficiency is a rare inborn error of immunity (IEI) characterized by autoimmunity and susceptibility to bacterial, fungal, and viral infections. PKCδ is involved in the intracellular production of reactive oxidative species (ROS).

MATERIAL AND METHODS

We studied a 5-year old girl presenting with a history of Burkholderia cepacia infection. She had no history of autoimmunity, lymphocyte counts were normal, and no auto-antibodies were detected in her plasma. We performed a targeted panel analysis of 407 immunity-related genes and immunological investigations of the underlying genetic condition in this patient.

RESULTS

Consistent with a history suggestive of chronic granulomatous disease (CGD), oxidative burst impairment was observed in the patient's circulating phagocytes in a dihydrorhodamine 123 (DHR) assay. However, targeted genetic panel analysis identified no candidate variants of known CGD-causing genes. Two heterozygous candidate variants were detected in PRKCD: c.285C > A (p.C95*) and c.376G > T (p.D126Y). The missense variant was also predicted to cause abnormal splicing, as it is located at the splice donor site of exon 5. TOPO-TA cloning confirmed that exon 5 was completely skipped, resulting in a truncated protein. No PKCδ protein was detected in the patient's neutrophils and monocyte-derived macrophages. The monocyte-derived macrophages of the patient produced abnormally low levels of ROS, as shown in an Amplex Red assay.

CONCLUSION

PKCδ deficiency should be considered in young patients with CGD-like clinical manifestations and abnormal DHR assay results, even in the absence of clinical and biological manifestations of autoimmunity.

Pathogenic autoantibodies to IFN-γ act through the impedance of receptor assembly and Fc-mediated response

Anti-interferon (IFN)-γ autoantibodies (AIGAs) are a pathogenic factor in late-onset immunodeficiency with disseminated mycobacterial and other opportunistic infections. AIGAs block IFN-γ function, but their effects on IFN-γ signaling are unknown. Using a single-cell capture method, we isolated 19 IFN-γ-reactive monoclonal antibodies (mAbs) from patients with AIGAs. All displayed high-affinity (KD < 10-9 M) binding to IFN-γ, but only eight neutralized IFN-γ-STAT1 signaling and HLA-DR expression. Signal blockade and binding affinity were correlated and attributed to somatic hypermutations. Cross-competition assays identified three nonoverlapping binding sites (I-III) for AIGAs on IFN-γ. We found that site I mAb neutralized IFN-γ by blocking its binding to IFN-γR1. Site II and III mAbs bound the receptor-bound IFN-γ on the cell surface, abolishing IFN-γR1-IFN-γR2 heterodimerization and preventing downstream signaling. Site III mAbs mediated antibody-dependent cellular cytotoxicity, probably through antibody-IFN-γ complexes on cells. Pathogenic AIGAs underlie mycobacterial infections by the dual blockade of IFN-γ signaling and by eliminating IFN-γ-responsive cells.

[Anti-cytokine autoantibodies: Review of the literature]

Anti-cytokine antibodies (ACA) are an emerging cause of acquired immunodeficiency, especially in previously healthy adults. The most frequently reported are anti-IFN-γ responsible for disseminated non-tuberculous mycobacteria infections, and anti-GM-CSF mainly in mycobacteria, cryptococcosis and nocardiosis infections. The presence of anti-IFN-α in severe COVID-19 infections has recently been described. The search for and detection of these ACAs in an unusual infection situation makes it possible to set up specific therapies in addition to the anti-infective treatment. ACAs are also frequent in various autoimmune pathologies where, in addition to being indicators of the breakdown of immune tolerance, they can modulate the activity of the disease according to their cytokine target. In this review of the literature, we will focus on the epidemiology and the clinical impact of these ACAs in healthy subjects and in infectious or dysimmune diseases.

Anti-cytokine autoantibodies and inborn errors of immunity

The past quarter of a century has witnessed an inordinate increase in our understanding of primary immunodeficiencies / inborn errors of immunity. These include a significant increase in the number of identified conditions, broadening the phenotypes of existing entities, delineation of classical inborn errors of immunity from those with a narrow phenotype, and a gradual shift from supportive to definitive care in patients afflicted with these diseases. It has also seen the discovery of conditions broadly defined as phenocopies of primary immunodeficiencies, where somatic mutations or autoantibodies mimic a recognised primary immunodeficiency's presentation in the absence of the underlying genetic basis for that disease. This article will provide a review of the anti-cytokine autoantibody-mediated phenocopies of inborn errors of immunity and discuss the therapeutic and laboratory aspects of this group of diseases.

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.

Clinical findings and predictive factors for positive anti-interferon-γ autoantibodies in patients suffering from a non-tuberculosis mycobacteria or Talaromyces marneffei infection: a multicenter prospective cohort study

We investigated the clinical features and screened for predictive factors of anti-interferon-γ autoantibody (AIGA) positivity. We enrolled 63 AIGA-positive (group 1) and 29 AIGA-negative (group 2) HIV-negative patients. White blood cell (WBC) and neutrophil counts, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP), globulin, immunoglobulin (Ig) G, and IgM levels were higher, whereas CD4⁺T cell count and hemoglobin level were lower in group 1 than in group 2. Co-infections, multiple infections, and disseminated infections were significantly higher in group 1 than in group 2. Prognosis was worse in group 1 than in group 2, especially for relapse and persistent infections. The number of infecting pathogens and sites involved; WBC and neutrophil counts; globulin, IgG, IgM, and CRP levels; and ESR were significantly positively correlated with AIGA titers; however, CD4⁺T cell count was significantly negatively correlated with AIGA titers. Therefore, IgG, globulin, and CRP levels; CD4⁺T cell and WBC counts; the number of infecting pathogens and sites involved; and ESR were considered potential predictors for AIGA positivity. For HIV-negative hosts with double or multiple opportunistic, disseminated infections and high serum IgG and globulin levels, low CD4⁺T cell count, and an increase in inflammatory marker levels, positive AIGA-associated immunodeficiency should be considered.

In Vitro Activity of Rifabutin against Mycobacterium abscessus, Including Clarithromycin-Insusceptible Multidrug-Resistant Clinical Isolates

The antibiotic options available for Mycobacterium abscessus (M. abscessus) infection are limited and no definitive therapeutic strategies have been formulated. The recent discovery that rifabutin is active against M. abscessus has raised interest in using rifabutin to treat this intractable disease. In this study, we evaluated the in vitro activity of rifabutin against 194 M. abscessus clinical isolates collected during 2012 January to 2017 December. As respected, rifabutin demonstrated considerably lower MICs against M. abscessus, with an MIC₅₀ of 2μg/ml and MIC₉₀ of 4μg/ml, respectively. Notably, the anti-M.abscessus activity was even stronger among clarithromycin-insusceptible strains. In addition, M. abscessus isolates with a rough morphotype were more sensitive to rifabutin compared with those forming smooth colonies when considered as a whole or in separate subspecies. Results from synergistic experiments revealed that the in vitro activity of rifabutin was significantly enhanced by the addition of amikacin, suggesting a promising strategy for M. abscessus infection combination treatment. Finally, five and three mutation patterns in rpoB and arr, respectively, were identified among the 194 strains through whole genome sequencing. However, none of them conferred rifabutin resistance. Our study is among the first to report the susceptibility of M. abscessus to rifabutin in vitro with a large amount of clinical isolates, suggesting that rifabutin is active, both alone and in combination, against M. abscessus and is worth considering as part of a combination treatment regimen for M. abscessus infections.

Sweet’s Syndrome Accompanied by Coinfection with Multiple Pathogens and Disseminated Mycobacterium phlei Infection Presenting with Osteolytic Destruction During 12 Years of Follow-Up: A Rare Case Report

Background

Anti-IFN-γ autoantibodies (AIGAs) are closely related to the disseminated infection of multiple pathogens. Mycobacterium phlei (M. phlei) is a nonpathogenic nontuberculous mycobacteria (NTM), and M. phlei infection of the bone is extremely rare. We report a rare case of high-titer AIGAs presenting with Sweet’s syndrome (SS) accompanied by opportunistic coinfection with multiple pathogens during 12 years of follow-up. The patient in this case also developed disseminated M. phlei infection with osteolytic destruction after treatment for SS.

Case Presentation

A 68-year-old Chinese woman was admitted to our hospital in August 2009 due to fever and cough with expectoration for 3 months. The patient was successively infected with Klebsiella pneumoniae, herpes zoster virus and Candida. Chest computed tomography (CT) showed recurrent consolidations in different lung fields. After 15 months of antimicrobial treatment, the patient experienced partial recovery. In September 2010, the patient was pathologically diagnosed with SS due to the presence of multiple rashes. After prednisone and thalidomide treatment, the rashes subsided, and the pulmonary lesions had completely absorbed. In May 2011, the patient was diagnosed with disseminated tuberculosis and was administered anti-tuberculosis therapy for 3 months without improvement. NTM was subsequently cultured from her sputum and chest wall pus, and she improved after 20 months of anti-NTM therapy. In March 2016, the patient developed osteolytic destruction of the C7-T2 vertebral bodies with a back abscess. NTM was eventually cultured from the dorsal abscess pus and further identified as M. phlei. High-titer AIGAs were detected in the patient’s serum. After another round of aggressive anti-NTM therapy, the patient was finally cured.

Conclusion

Patients with AIGA-associated anti-cytokine autoantibody disease can present with multiple opportunistic infections and SS involving the lung. AIGA-associated immunodeficiency leads to infection with nonpathogenic M. phlei, which is refractory, can cause relapse, and even leads to osteolytic destruction.

Inborn Errors of Immunity in Algerian Children and Adults: A Single-Center Experience Over a Period of 13 Years (2008–2021)

Background

Inborn errors of immunity (IEI) predispose patients to various infectious and non-infectious complications. Thanks to the development and expanding use of flow cytometry and increased awareness, the diagnostic rate of IEI has markedly increased in Algeria the last decade.

Aim

This study aimed to describe a large cohort of Algerian patients with probable IEI and to determine their clinical characteristics and outcomes.

Methods

We collected and analyzed retrospectively the demographic data, clinical manifestations, immunologic, genetic data, and outcome of Algerian IEI patients - diagnosed in the department of medical immunology of Beni Messous university hospital center, Algiers, from 2008 to 2021.

Results

Eight hundred and seven patients with IEI (482 males and 325 females) were enrolled, 9.7% of whom were adults. Consanguinity was reported in 50.3% of the cases and a positive family history in 32.34%. The medium age at disease onset was 8 months and at diagnosis was 36 months. The median delay in diagnosis was 16 months. Combined immunodeficiencies were the most frequent (33.8%), followed by antibody deficiencies (24.5%) and well-defined syndromes with immunodeficiency (24%). Among 287 patients tested for genetic disorders, 129 patients carried pathogenic mutations; 102 having biallelic variants mostly in a homozygous state (autosomal recessive disorders). The highest mortality rate was observed in patients with combined immunodeficiency (70.1%), especially in patients with severe combined immunodeficiency (SCID), Omenn syndrome, or Major Histocompatibility Complex (MHC) class II deficiency.

Conclusion

The spectrum of IEI in Algeria is similar to that seen in most countries of the Middle East and North Africa (MENA) region, notably regarding the frequency of autosomal recessive and/or combined immunodeficiencies.

Human autoantibodies underlying infectious diseases

The vast interindividual clinical variability observed in any microbial infection—ranging from silent infection to lethal disease—is increasingly being explained by human genetic and immunological determinants. Autoantibodies neutralizing specific cytokines underlie the same infectious diseases as inborn errors of the corresponding cytokine or response pathway. Autoantibodies against type I IFNs underlie COVID-19 pneumonia and adverse reactions to the live attenuated yellow fever virus vaccine. Autoantibodies against type II IFN underlie severe disease caused by environmental or tuberculous mycobacteria, and other intra-macrophagic microbes. Autoantibodies against IL-17A/F and IL-6 are less common and underlie mucocutaneous candidiasis and staphylococcal diseases, respectively. Inborn errors of and autoantibodies against GM-CSF underlie pulmonary alveolar proteinosis; associated infections are less well characterized. In individual patients, autoantibodies against cytokines preexist infection with the pathogen concerned and underlie the infectious disease. Human antibody-driven autoimmunity can interfere with cytokines that are essential for protective immunity to specific infectious agents but that are otherwise redundant, thereby underlying specific infectious diseases.

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.

Morphologic Spectrum of Lymphadenopathy in Adult-onset Immunodeficiency (Anti-interferon-γ Autoantibodies)

Adult-onset immunodeficiency syndrome (AOIS) caused by anti-interferon-γ autoantibodies is an emerging disease. Affected patients present typically with systemic lymphadenopathy, fatigue, and fever. We studied 36 biopsy specimens, 31 lymph nodes, and 5 extranodal sites, of AOIS confirmed by serum autoantibody or QuantiFERON-TB Gold In-Tube assay. We describe the morphologic features and the results of ancillary studies, including special stains, immunohistochemistry, and molecular testing. The overall median age of these patients was 60.5 years (range, 41 to 83 y) with a male-to-female ratio of 20:16. All biopsy specimens showed nontuberculous mycobacterial infection, and most cases showed the following histologic features: capsular thickening with intranodal sclerosing fibrosis, irregularly distributed ill-formed granulomas or histiocytic aggregates with neutrophilic infiltration, interfollicular expansion by a polymorphic infiltrate with some Hodgkin-like cells that commonly effaces most of the nodal architecture and proliferation of high endothelial venules. In situ hybridization analysis for Epstein-Barr virus-encoded RNA showed scattered (<1%) to relatively more common (4% to 5%) positive cells in 29 of 30 (97%) tested specimens, reflecting immune dysregulation due to an interferon-γ defect. In the 31 lymph node specimens, 23 (74%) cases showed increased immunoglobulin G4-positive plasma cells (4 to 145/HPF; mean, 49.7/HPF) with focal areas of sclerosis reminiscent of immunoglobulin G4-related lymphadenopathy, 4 (13%) cases resembled, in part, nodular sclerosis Hodgkin lymphoma, and 9 (29%) cases mimicked T-cell lymphoma. Among 33 patients with available clinical follow-up, 20 (61%) showed persistent or refractory disease despite antimycobacterial therapy, and 1 patient died of the disease. We conclude that the presence of ill-defined granulomas, clusters of neutrophils adjacent to the histiocytic aggregates, and some Epstein-Barr virus-positive cells are features highly suggestive of AOIS. A high index of clinical suspicion and awareness of the morphologic features and differential diagnosis of AOIS are helpful for establishing the diagnosis.

Adult-onset immunodeficiency due to anti-interferon-gamma autoantibody-associated Sweet syndrome: A distinctive entity

Sweet syndrome (SS) has been increasingly reported in patients with adult-onset immunodeficiency (AOID) due to anti-interferon-γ autoantibody who also have concomitant opportunistic infections, especially disseminated non-tuberculous mycobacterial infection (dNTMI). A retrospective study retrieving data from 2011 through 2020 was conducted. We compared clinical characteristics of SS with and without AOID and generated the prediction model and examined the interaction between AOID and dNTMI in the occurrence of SS. Lymphadenopathy, pustular lesions, and leukocytosis are the significant predictors for AOID-associated SS. Adjusted risk differences were 0.58 (95% confidence interval [CI], 0.33-0.83), 0.21 (95% CI, 0.02-0.39), and 0.24 (95% CI, 0.01-0.47), respectively. Based on the analysis of aggregated cross-sectional data, both the overall and the direct effect of AOID increased the prevalence of SS. The indirect effect of AOID on the occurrence of SS might also be mediated through dNTMI or other common opportunistic infections. In addition, there was a trend of positive additive interaction between AOID and dNTMI. Although the test of additive interaction did not reveal statistically significant results, a deviation from additivity of isolated effects might suggest potential causal interaction between AOID and dNTMI. The distinctive clinical syndrome comprising lymphadenopathy, pustular lesions, and leukocytosis in patients with SS should raise the awareness of clinicians to the potential of underlying AOID.

Endobronchial Lesions from Disseminated Mycobacterium avium Infection in a Patient with Anti-interferon-gamma Autoantibodies

A 78-year-old man was admitted to our hospital with a fever and left chest pain. Computed tomography showed multiple lung nodules, narrowing of the right bronchus intermedius with mediastinal lymphadenopathy, and an osteolytic lesion. Bronchoscopic findings showed rapid progression of multiple polypoid lesions and the bronchial stenosis. A biopsy of the endobronchial lesions revealed non-necrotizing granulomatous inflammation, and a tissue culture identified Mycobacterium avium. An anti-human immunodeficiency virus antibody was negative. Finally, anti-interferon-gamma (IFN-γ) autoantibodies were detected, and the patient was diagnosed with disseminated nontuberculous mycobacterium infection with anti-IFN-γ autoantibodies. Antimycobacterial therapy was effective, and radiographic findings, including the endobronchial lesions, were resolved.

Application of QuantiFERON ELISA for Detection of Interferon-Gamma Autoantibodies in Adult-Onset Immunodeficiency Syndrome

OBJECTIVE

Patients who develop interferon-gamma autoantibodies (IFN-ɤ autoAbs) in adult-onset immunodeficiency (AOID) syndrome are more likely to develop opportunistic and recurrent intracellular infections. The assay to detect IFN-ɤ autoAbs is essential for the diagnosis and therapeutic monitoring of AOID syndrome. Therefore, this study applied the QuantiFERON assay for the detection of IFN-ɤ autoAbs.

METHODS

Serum from patients with AOID syndrome (n = 19) and serum from healthy patients (n = 20) was collected and applied using 2 neutralizing platforms of enzyme-linked immunosorbent assay (ELISA) kits (the BD ELISA and the QuantiFERON ELISA) for IFN-ɤ autoAbs detection.

RESULTS

The pooled serum from patients with AOID syndrome showed >50% inhibition at 1:5000 dilution (positive), whereas the pooled serum from healthy patients showed <50% inhibition at 1:5000 dilution (negative) according to the neutralizing QuantiFERON ELISA. Each specimen showed the same result according to both the neutralizing BD ELISA and the neutralizing QuantiFERON ELISA. Moreover, the patient serum showed a variation in titer ranging from 1:5000 to >1:5,000,000 according to the neutralizing QuantiFERON ELISA.

CONCLUSION

The QuantiFERON ELISA kit could be applied for the detection of IFN-ɤ autoAbs for the diagnosis and therapeutic monitoring of AOID syndrome.

Talaromyces marneffei and nontuberculous mycobacteria co-infection in HIV-negative patients

To describe the clinical features and the risk factors for nontuberculous mycobacteria (NTM) and Talaromyces marneffei (TM) co-infections in HIV-negative patients. A multicenter retrospective study in 13 hospitals, and a systematic literature review were performed of original articles published in English related to TM/NTM co-infections. HIV-negative patients with TM and NTM co-infections comprised Group 1; TM-only infection Group 2; NTM-only infection Group 3; and healthy volunteers Group 4. Univariate logistic analysis was used to estimate the potential risk factors of TM/NTM co-infections. A total of 22 cases of TM and NTM co-infections were enrolled. Of these, 17 patients (77.3%) had a missed diagnosis of one of the TM or NTM pathogens. The anti-IFN-γ autoantibodies (AIGAs) titer, white blood cell (WBC), neutrophil counts (N), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), globulin, and immunoglobulin G (IgG) levels of Group 1 were higher than those of the other groups, whereas the levels of CD4⁺T cells was lower than those of other groups. There was a significant negative correlation between the AIGA titers and the number of CD4⁺T cells (P < 0.05). Factors including the ratio of the actual values to the cut-off values of AIGAs, WBC, N, HGB, CD4⁺T cells, IgG, IgM, IgA, serum globulin, ESR, and CRP were taken as potential risk factors for TM and NTM co-infection. Most patients with TM and NTM co-infection had a missed diagnosis of one of the TM or NTM pathogens. The levels of AIGAs, WBC, N, ESR, and CRP in TM and NTM co-infections were remarkably higher than in mono-infection. High-titer AIGAs may be a potential risk factor and susceptibility factor for co-infection of TM and NTM in HIV-negative hosts.

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.

Treatment Dilemmas in Disseminated Nontuberculous Mycobacterial Infections With Interferon-gamma Autoantibodies

Disseminated Mycobacterium avium complex (dMAC) is typically seen in individuals with impaired cell-mediated immunity and is best described in those with HIV. Recently, cases have been described in otherwise healthy individuals with neutralizing antibodies to interferon-gamma (nIFNγ-autoAb), especially in patients of Southeast Asian descent. Treatment is often refractory to mycobacterial therapies, and the use of rituximab and other immunomodulatory agents has been explored. We report 3 cases of dMAC with nIFN-γ-autoAb and review the available literature on treatment strategies to provide a framework for the management of patients with refractory infections in the context of neutralizing antibodies to interferon-gamma.

Talaromyces marneffei and Burkholderia cepacia Co-Infection in a HIV-Uninfected Patient with Anti-Interferon-γ Autoantibodies

A high titer of neutralizing anti-interferon-γ autoantibodies can cause immunodeficiency associated with severe or disseminated infections caused by Talaromyces marneffei in human immunodeficiency virus-negative patients. Herein, we reported a rare case of disseminated Talaromyces marneffei and Burkholderia cepacia infection. The patient’s lungs, lymph nodes, and bronchi were involved, and he had neck abscesses and osteomyelitis. We measured the neutralizing anti-interferon-γ autoantibodies in the peripheral blood and found that the patient had a persistently high positive titer. Despite aggressive treatment, the patient developed disseminated intravascular coagulation and died. Thus, high-titer nAIGAs may be associated with multiple opportunistic, persistent and disseminated infections.

Anti-interferon-gamma autoantibody related disseminated nontuberculous mycobacteriosis with pathological features of immunoglobulin G4-related disease

A 72-year-old man who was diagnosed as pulmonary mycobacterium avium complex (MAC) disease had suffered from antibiotics resistant fever with left renal enlargement surrounded by inflammatory change and multiple osteolytic lesions on computed tomography (CT). The renal biopsied samples pathologically showed immunoglobulin G4 (IgG4) positive plasma cell infiltration and many acid-fast bacilli without granuloma formation. Nucleic acid identification test for MAC from the samples of vertebral osteolytic lesion was positive. In the autopsy samples from left kidney, epithelioid cell granuloma and Langhans giant cell with many acid-fast bacilli were shown pathologically. In addition to osteolytic lesions on CT study, these pathological findings were not consistent with IgG4-related disease (IgG4-RD). The diagnosis of disseminated nontuberculous mycobacteriosis was made, and plasma anti-interferon-gamma (IFN-γ) autoantibody was found as the cause of underlying immunodeficiency. Disturbed function of IFN-γ resulted in impaired ability of phagocytic cells against pathogens and leading to spread of infection. T-helper type 2 dominant immune response was induced by prolonged antigenic stimulation of mycobacteria, which might have contributed to form the pathological features of IgG4-RD.

R-CHOP Chemotherapy for Disseminated Mycobacterium avium Complex Disease due to Anti-Interferon-Gamma Autoantibodies: A Case Report

A 77-year-old Japanese man with disseminated Mycobacterium avium complex (MAC) disease due to anti-interferon-gamma autoantibodies received rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) chemotherapy because of non-Hodgkin lymphoma complication. The hepatobiliary nodules due to MAC resolved with R-CHOP and multidrug antimycobacterial treatment. R-CHOP could serve as an alternative adjunctive therapy for patients with anti-interferon-gamma autoantibodies.

Anti-IFN-γ autoantibodies underlie disseminated Talaromyces marneffei infections

Talaromyces marneffei causes life-threatening opportunistic infections, mainly in Southeast Asia and South China. T. marneffei mainly infects patients with human immunodeficiency virus (HIV) but also infects individuals without known immunosuppression. Here we investigated the involvement of anti-IFN-γ autoantibodies in severe T. marneffei infections in HIV-negative patients. We enrolled 58 HIV-negative adults with severe T. marneffei infections who were otherwise healthy. We found a high prevalence of neutralizing anti-IFN-γ autoantibodies (94.8%) in this cohort. The presence of anti-IFN-γ autoantibodies was strongly associated with HLA-DRB1*16:02 and -DQB1*05:02 alleles in these patients. We demonstrated that adult-onset acquired immunodeficiency due to autoantibodies against IFN-γ is the major cause of severe T. marneffei infections in HIV-negative patients in regions where this fungus is endemic. The high prevalence of anti-IFN-γ autoantibody-associated HLA class II DRB1*16:02 and DQB1*05:02 alleles may account for severe T. marneffei infections in Southeast Asia. Our findings clarify the pathogenesis of T. marneffei infection and pave the way for developing novel treatments.

Simultaneous disseminated infections with intracellular pathogens: an intriguing case report of adult-onset immunodeficiency with anti-interferon-gamma autoantibodies

Background

Severe and disseminated non-tuberculous mycobacterial (NTM) infections are frequently linked to a genetic predisposition but acquired defects of the interferon gamma (IFNγ) / interleukin 12 (IL-12) pathway need to be considered in adult patients with persistent or recurrent infections. Neutralizing anti-IFNγ autoantibodies disrupting IFNγ signalling have been identified as the cause of a severe and unique acquired immunodeficiency syndrome with increased susceptibility to NTM and other intracellular pathogens.

Case presentation

An adult Asian female with a previous history of recurrent NTM infections presented with persistent diarrhea, abdominal pain, night sweats and weight loss. Severe colitis due to a simultaneous infection with cytomegalovirus (CMV) and Salmonella typhimurium was diagnosed, with both pathogens also detectable in blood samples. Imaging studies further revealed thoracic as well as abdominal lymphadenopathy and a disseminated Mycobacterium intracellulare infection was diagnosed after a lymph node biopsy. Further diagnostics revealed the presence of high-titer neutralizing anti-IFNγ autoantibodies, allowing for the diagnosis of adult-onset immunodeficiency with anti-IFNγ autoantibodies (AIIA).

Conclusions

We here present a severe case of acquired immunodeficiency with anti-IFNγ autoantibodies with simultaneous, disseminated infections with both viral and microbial pathogens. The case illustrates how the diagnosis can cause considerable difficulties and is often delayed due to unusual presentations. Histological studies in our patient give further insight into the pathophysiological significance of impaired IFNγ signalling. B-cell-depleting therapy with rituximab offers a targeted treatment approach in AIIA.