Anticytokine autoantibodies: Autoimmunity trespassing on antimicrobial immunity

Fatal Mycobacterium avium meningitis in an HIV-negative Vietnamese man: a case report

BACKGROUND

Nontuberculous mycobacteria are environmental mycobacteria that rarely cause human disease, especially in the central nervous system. Central nervous system infection by Mycobacterium avium complex, the most common pathogen among nontuberculous mycobacteria species, is rare and seldom reported, even in those with advanced human immunodeficiency virus infection. We describe a case of Mycobacterium avium complex meningitis with cerebral hemorrhage in an human immunodeficiency virus uninfected man in Vietnam.

CASE PRESENTATION

A 56-year-old Vietnamese man with hypertension was hospitalized with a 5-day history of headache, dizziness, low-grade fever, and unresponsive to 5 days of oral antibiotics. A brain magnetic resonance imaging, performed on day 12, showed hydrocephalus and lacunar infarct. The patient did not improve with 8 days of empirical treatment with ceftriaxone, vancomycin, dexamethasone, and meropenem, and was transferred to a referral hospital for tropical diseases. At the second hospital admission, a cerebrospinal fluid analysis showed a white cell count of 22,518 cells/μL with 81% neutrophils, protein 1.72 g/L, and glucose 0.85 mmol/L. Acid-fast bacilli smear of the cerebrospinal fluid was positive. Molecular testing of the cerebrospinal fluid was negative on GeneXpert Ultra testing, while the line probe assay was positive for Mycobacterium avium. Blood cultures at two sites, cerebrospinal fluid cultures for bacteria and fungi, and human immunodeficiency virus Ag/Ab test were negative. The patient was continuously administered meropenem with the addition of azithromycin, rifampin, and ethambutol. Then, 1 day after nontuberculous mycobacteria treatment, he developed right-sided hemiplegia, and brain computed tomography showed a hemorrhage in the parietal area, adjacent to the left lateral ventricle, and left lateral intraventricular hemorrhage shifts the midline to the right. He was transferred to the third referral general hospital and died 22 days after the onset of symptoms.

CONCLUSION

Nontuberculous mycobacteria-central nervous system infection might mimic unresponsive pyogenic bacterial meningitis. A rapid and accurate diagnosis is essential for initiating appropriate therapy for this deadly disease.

Concomitant autoimmunity and late cancers in adult-onset immunodeficiency due to neutralizing anti-IFN-γ autoantibodies

Background

Opportunistic intramacrophagic infections are well-characterized in adult-onset immunodeficiency associated with neutralizing anti-IFN-γ autoantibodies (nAIGA).

Objective

Concomitant autoimmune and neoplastic diseases are rarely described.

Methods

This study included 50 patients diagnosed with adult-onset immunodeficiency due to nAIGA between 2014-2024. Thirty-three were retrospectively included before January 2022, and 17 out of 295 screened patients were enrolled prospectively since January 2022. Ten patients were excluded due to missing records. All patients had regular follow-ups; anti-IFN-γ titers, autoimmune markers and cancer survey were conducted according to the primary physician's evaluation.

Results

The median age at diagnosis of adult-onset immunodeficiency was 57 years, and 53% were men. Malignancy occurred in 25%; genitourinary cancer predominated (n=4). Most (93%) patients had at least one positive autoimmune marker. Fifty-eight percent of patients were diagnosed with concomitant autoimmune diseases, and women (65%) predominated. Anti-nuclear antibody was positive in 61%, lupus anticoagulant in 50%, whilst autoimmune thyroiditis markers in 43%. Twenty-two percent of patients required long-term immunomodulation including biologic agents such as rituximab and daratumumab. Three patients (8%) died after a median interval of 9.4 years due to sepsis (n=2) and aggressive urothelial cancer (n=1). Most patients had decreasing nAIGA titers over time; two outliers with persistently high neutralizing antibodies developed late-onset malignancies.

Conclusion

Adult-onset immunodeficiency due to nAIGA is a syndrome associated with concomitant autoimmunity. Chronic infection and autoimmune-mediated inflammation may foster neoplastic changes, but the underlying mechanism is still undetermined. Autoimmune disease and cancer surveillance for patients with nAIGA is advised.

Case Report: Anti-interferon-γ autoantibodies in an adolescent with disseminated Talaromyces marneffei and mycobacterial co-infections

Background

Anti-interferon-γ autoantibodies (AIGAs) are associated with adult-onset immunodeficiency syndrome, which makes individuals susceptible to intracellular pathogen infections. However, AIGAs are rarely reported in adolescents.

Case presentation

We report a 13-year-old Chinese boy who presented with fever, cough, and enlarged cervical lymph nodes. Blood cultures yielded Mycobacterium abscessus, and Talaromyces marneffei (TM) was cultured from pericardial effusion. Whole exome sequencing revealed no pathogenic variants. Notably, high levels of neutralizing AIGAs were detected in the patient's serum. After receiving treatment for Mycobacterium abscessus and antifungal therapy for TM, the patient showed significant improvement. However, at the 19-month follow-up, the patient developed a Mycobacterium asiaticum infection.

Conclusion

This case highlights the importance of screening for AIGAs in pediatric patients with disseminated TM or NTM infections. Prolonged treatment and continuous follow-up remains crucial for managing pediatric patients with AIGAs.

Clinical Characteristics Analysis of 30 Cases of Interferon-γ Autoantibody-Positive Patients with Concurrent Mycobacterial Infection: A 6-Year Retrospective Study

Purpose

This study aimed to investigate and elucidate the clinical characteristics, immune status, infection types and patterns, treatment responses, and disease progression in patients with positive anti-interferon-gamma (IFN-γ) autoantibodies in combination with Mycobacterium infections.

Patients and Methods

We conducted a retrospective analysis of clinical data from patients with positive anti-IFN-γ autoantibodies and concurrent Mycobacterial infections, including Mycobacterial infections (MTB) and non-tuberculous mycobacteria (NTM). The study included cases treated at the Fourth People's Hospital of Nanning, Guangxi, from 2018 to 2023. Data collected comprised symptoms, clinical signs, laboratory test results, imaging findings, and other relevant clinical information. Patients were also followed up to evaluate treatment responses and long-term therapeutic outcomes.

Results

A total of 30 patients with MTB and NTM infections were analyzed. The majority presented with common symptoms, such as cough, sputum production, weight loss, extrapulmonary tuberculosis (TB), and a range of opportunistic infections. Laboratory and imaging studies revealed complex infection patterns and various pathological changes. Treatment primarily involved targeted anti-infective therapy combined with immunosupportive measures. However, frequent treatment relapses and side effects were observed, resulting in two deaths.

Conclusion

Immune deficiency associated with positive anti-IFN-γ autoantibodies resembles the immunosuppression seen in advanced stages of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS), rendering patients highly susceptible to opportunistic infections. These infections were predominantly caused by NTM, followed by MTB and Talaromyces marneffei (TM). This represents a novel immune deficiency syndrome that predisposes patients to a spectrum of opportunistic infections.

Anti-IL12p40 autoantibodies in a teenage girl with multiple recurrent abscesses

More frequent among adults, phenocopies may be caused by somatic mutations or anti-cytokine autoantibodies, mimicking the phenotypes of primary immunodeficiencies. A fourteen-year-old girl was referred for a two-year history of weight loss and multiple recurrent abscesses, complicated recurrent pneumonia, pyelonephritis, osteomyelitis, and septic shock, without fever. She had started with nausea, hyporexia, and weight loss, then with abscesses in her hands, knee, ankle, and spleen. She also developed a rib fracture and left thoracic herpes zoster. The patient was cachectic, with normal vital signs, bilateral crackles on chest auscultation, tumefaction of the knee joint, and poorly healed wounds in hands and chest, oozing a yellowish fluid. Chest computed tomography revealed multiple bilateral bronchiectases. Laboratory workup reported chronic anemia, leukocytosis, neutrophilia, mild lymphopenia, thrombocytosis, pan-hypergammaglobulinemia, and elevated acute serum reactants. Lymphocyte subsets were low but present. Mycobacterium tuberculosis was detected via polymerase chain reaction in a bone biopsy specimen from ankle osteomyelitis. Whole-exome sequencing failed to identify a monogenic defect. Interleukin-12 was found markedly elevated in the serum of the patient. Phosphorylation of STAT4, induced by increasing doses of IL-12, was neutralized by patient serum, confirming the presence of anti-IL12 autoantibodies. IL-12 and IL-23 are crucial cytokines in the defense against intracellular microorganisms, the induction of interferon-gamma production by lymphocytes, and other inflammatory functions. Patients who develop neutralizing serum autoantibodies against IL12 manifest late in life with weight loss, multiple recurrent abscesses, poor wound healing, and fistulae. Treatment with anti-CD20 monoclonal antibodies was effective.

Autoantibodies in COVID-19 and Other Viral Diseases: Molecular, Cellular, and Clinical Perspectives

Autoantibodies are immune system-produced antibodies that wrongly target the body's cells and tissues for attack. The COVID-19 pandemic has made it possible to link autoantibodies to both the severity of pathogenic infection and the emergence of several autoimmune diseases after recovery from the infection. An overview of autoimmune disorders and the function of autoantibodies in COVID-19 and other infectious diseases are discussed in this review article. We also investigated the different categories of autoantibodies found in COVID-19 and other infectious diseases including the potential pathways by which they contribute to the severity of the illness. Additionally, it also highlights the probable connection between vaccine-induced autoantibodies and their adverse outcomes. The review also discusses the therapeutic perspectives of autoantibodies. This paper advances our knowledge about the intricate interaction between autoantibodies and COVID-19 by thoroughly assessing the most recent findings.

Anti-Interleukin-23 Autoantibodies in Adult-Onset Immunodeficiency

BACKGROUND

Autoantibodies against interleukin-12 (anti-interleukin-12) are often identified in patients with thymoma, but opportunistic infections develop in only some of these patients. Interleukin-12 (with subunits p40 and p35) shares a common subunit with interleukin-23 (subunits p40 and p19). In a patient with disseminated Burkholderia gladioli infection, the identification of both anti-interleukin-23 and anti-interleukin-12 prompted further investigation.

METHODS

Among the patients (most of whom had thymoma) who were known to have anti-interleukin-12, we screened for autoantibodies against interleukin-23 (anti-interleukin-23). To validate the potential role of anti-interleukin-23 with respect to opportunistic infection, we tested a second cohort of patients with thymoma as well as patients without either thymoma or known anti-interleukin-12 who had unusual infections.

RESULTS

Among 30 patients with anti-interleukin-12 who had severe mycobacterial, bacterial, or fungal infections, 15 (50%) also had autoantibodies that neutralized interleukin-23. The potency of such neutralization was correlated with the severity of these infections. The neutralizing activity of anti-interleukin-12 alone was not associated with infection. In the validation cohort of 91 patients with thymoma, the presence of anti-interleukin-23 was associated with infection status in 74 patients (81%). Overall, neutralizing anti-interleukin-23 was detected in 30 of 116 patients (26%) with thymoma and in 30 of 36 patients (83%) with disseminated, cerebral, or pulmonary infections. Anti-interleukin-23 was present in 6 of 32 patients (19%) with severe intracellular infections and in 2 of 16 patients (12%) with unusual intracranial infections, including Cladophialophora bantiana and Mycobacterium avium complex.

CONCLUSIONS

Among patients with a variety of mycobacterial, bacterial, or fungal infections, the presence of neutralizing anti-interleukin-23 was associated with severe, persistent opportunistic infections. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

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.

Disseminated tuberculosis, CMV viraemia & haemophagocytic-lymphohistiocystosis syndrome in an adult patient with anti- IFNγ autoantibodies - case report and brief review

We report a case of an adult female with disseminated tuberculosis, cytomegalovirus viraemia and haemophagocytic-lymphohistiocystosis syndrome associated with neutralizing anti- interferon gamma (IFNγ) autoantibodies demonstrated by absent IFNγ stimulated STAT1 phosphorylation in the presence of patient sera. A brief review of immunodeficiency caused by anti-IFNγ autoantibodies is also described.

Cluster analysis of flowcytometric immunophenotyping with extended T cell subsets in suspected immunodeficiency

BACKGROUND

Patients with immunodeficiencies commonly experience diagnostic delays resulting in morbidity. There is an unmet need to identify patients earlier, especially those with high risk for complications. Compared to immunoglobulin quantification and flowcytometric B cell subset analysis, expanded T cell subset analysis is rarely performed in the initial evaluation of patients with suspected immunodeficiency. The simultaneous interpretation of multiple immune variables, including lymphocyte subsets, is challenging.

OBJECTIVE

To evaluate the diagnostic value of cluster analyses of immune variables in patients with suspected immunodeficiency.

METHODS

Retrospective analysis of 38 immune system variables, including seven B cell and sixteen T cell subpopulations, in 107 adult patients (73 with immunodeficiency, 34 without) evaluated at a tertiary outpatient immunology clinic. Correlation analyses of individual variables, k-means cluster analysis with evaluation of the classification into "no immunodeficiency" versus "immunodeficiency" and visual analyses of hierarchical heatmaps were performed.

RESULTS

Binary classification of patients into groups with and without immunodeficiency was correct in 54% of cases with the full data set and increased to 69% and 75% of cases, respectively, when only 16 variables with moderate (p < .05) or 7 variables with strong evidence (p < .01) for a difference between groups were included. In a cluster heatmap with all patients but only moderately differing variables and a heatmap with only immunodeficient patients restricted to T cell variables alone, segregation of most patients with common variable immunodeficiency and combined immunodeficiency was observed.

CONCLUSION

Cluster analyses of immune variables, including detailed lymphocyte flowcytometry with T cell subpopulations, may support clinical decision making for suspected immunodeficiency in daily practice.

Approach to Diagnosing Inborn Errors of Immunity

Inborn errors of immunity are now understood to encompass manifold features including but not limited to immunodeficiency, autoimmunity, autoinflammation, atopy, bone marrow defects, and/or increased malignancy risk. As such, it is essential to maintain a high index of suspicion, as these disorders are not limited to specific demographics such as children or those with recurrent infections. Clinical presentations and standard immunophenotyping are informative for suggesting potential underlying etiologies, but integration of data from multimodal approaches including genomics is often required to achieve diagnosis.

Anticytokine Autoantibodies and Fungal Infections

Anticytokine autoantibodies (ACAAs) can cause adult onset immunodeficiencies which mimic primary immunodeficiencies and can present as refractory and severe fungal infections. This paper provides an overview of the role of innate immunity, including key cytokines, in fungal infections and then describes four clinical scenarios where ACAAs are associated with severe presentations of a fungal infection: (1) Talaromyces marneffei infection and anti-interferon-γ, (2) histoplasmosis and anti-interferon-γ, (3) Cryptococcus gattii infection and anti-GM-CSF, and (4) mucocutaneous candidiasis and anti-IL-17A/F (IL-22). Testing for ACAAs and potential therapeutic options are discussed.

Immunocompromised Host Pneumonia: Definitions and Diagnostic Criteria: An Official American Thoracic Society Workshop Report

Pneumonia imposes a significant clinical burden on people with immunocompromising conditions. Millions of individuals live with compromised immunity because of cytotoxic cancer treatments, biological therapies, organ transplants, inherited and acquired immunodeficiencies, and other immune disorders. Despite broad awareness among clinicians that these patients are at increased risk for developing infectious pneumonia, immunocompromised people are often excluded from pneumonia clinical guidelines and treatment trials. The absence of a widely accepted definition for immunocompromised host pneumonia is a significant knowledge gap that hampers consistent clinical care and research for infectious pneumonia in these vulnerable populations. To address this gap, the American Thoracic Society convened a workshop whose participants had expertise in pulmonary disease, infectious diseases, immunology, genetics, and laboratory medicine, with the goal of defining the entity of immunocompromised host pneumonia and its diagnostic criteria.

Transient autoantibodies to danger signals

The Danger Model predicts that there are some molecules that no immune system can ever be fully tolerant of, namely proteins that are only transiently expressed during times of stress, infection, or injury. Among these are the danger/alarm signals themselves. Accordingly, a fleeting autoantibody response to danger signals is expected during times when they are released. Depending on context, these autoantibodies may serve beneficial "housekeeping" functions by removing surplus danger signals from the circulation or, conversely, create an immunodeficiency. Here, we will focus on the Type 1 Interferons as examples of foreseeable targets for a transient autoantibody response, but the principles outlined should hold for other danger-associated molecules as well.

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.

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.