TACI mutation in Good's Syndrome: in search of a genetic basis

Good syndrome combined with multiple microbial pulmonary infections: case report and review of the literature

Good syndrome (GS), a rare acquired immunodeficiency disorder characterized by thymoma and hypogammaglobulinemia, predisposes individuals to recurrent infections. This study reports a case of a 37-year-old male GS with multiple pulmonary infections and reviews relevant literature. The patient, with a history of thymoma resection, experienced multiple hospitalizations due to lung infections and neutropenia. The alveolar lavage fluid was detected by macro-genomic sequencing (NGS) to detect multiple pathogens, and targeted anti-infective and immunity-enhancing treatments led to improved symptoms and normal neutrophil counts. A literature review of 98 case reports from 2000 to 2023 was conducted, summarizing the associated diseases and pathogens in GS patients. Regular immunoglobulin monitoring in thymoma patients is essential for early GS diagnosis. When empirical antimicrobial therapy fails, mNGS for pathogen detection and targeted therapy are crucial, and regular IVIG injections can reduce infection rates in GS patients.

Good syndrome and cytomegalovirus retinitis: A literature review

Good syndrome (GS) is a rare primary immunodeficiency in adults consisting of hypogammaglobulinemia and thymoma that affects both cellular and humoral immunity. It usually appears in patients between the 4th and 6th decade of life and affects both genders equally. Ophthalmological clinical presentation is highly variable; associations with herpetic keratitis, toxoplasmosis, and cytomegalovirus retinitis (CMVR) have been described. GS associated with CMVR is uncommon. Ophthalmologists may be the first to diagnose systemic disease and change the outcome. Only18 cases of CMVR have been described, most of them unilateral with poor visual outcomes. We discuss the clinical features of CMVR in patients with reported GS, pathogenesis, and outline a work-up for diagnosis. CMVR in an apparently healthy patient should encourage the clinician to search for human immunodeficiency virus (HIV) and non-HIV-associated immunosuppression.

In-depth blood immune profiling of Good syndrome patients

Introduction

Good syndrome (GS) is a rare adult-onset immunodeficiency first described in 1954. It is characterized by the coexistence of a thymoma and hypogammaglobulinemia, associated with an increased susceptibility to infections and autoimmunity. The classification and management of GS has been long hampered by the lack of data about the underlying immune alterations, a controversy existing on whether it is a unique diagnostic entity vs. a subtype of Common Variable Immune Deficiency (CVID).

Methods

Here, we used high-sensitive flow cytometry to investigate the distribution of up to 70 different immune cell populations in blood of GS patients (n=9) compared to age-matched CVID patients (n=55) and healthy donors (n=61).

Results

All 9 GS patients displayed reduced B-cell counts -down to undetectable levels (<0.1 cells/μL) in 8/9 cases-, together with decreased numbers of total CD4+ T-cells, NK-cells, neutrophils, and basophils vs. age-matched healthy donors. In contrast, they showed expanded TCRγδ+ T-cells (p ≤ 0.05). Except for a deeper B-cell defect, the pattern of immune cell alteration in blood was similar in GS and (age-matched) CVID patients. In depth analysis of CD4+ T-cells revealed significantly decreased blood counts of naïve, central memory (CM) and transitional memory (TM) TCD4+ cells and their functional compartments of T follicular helper (TFH), regulatory T cells (Tregs), T helper (Th)2, Th17, Th22, Th1/Th17 and Th1/Th2 cells. In addition, GS patients also showed decreased NK-cell, neutrophil, basophil, classical monocyte and of both CD1c+ and CD141+ myeloid dendritic cell counts in blood, in parallel to an expansion of total and terminal effector TCRγδ+ T-cells. Interestingly, those GS patients who developed hypogammaglobulinemia several years after the thymoma presented with an immunological and clinical phenotype which more closely resembled a combined immune humoral and cellular defect, with poorer response to immunoglobulin replacement therapy, as compared to those in whom the thymoma and hypogammaglobulinemia were simultaneously detected.

Discussion

Our findings provide a more accurate definition of the immune cell defects of GS patients and contribute to a better discrimination among GS patients between those with a pure B-cell defect vs. those suffering from a combined immunodeficiency with important consequences on the diagnosis and management of the disease.

Insights from a Case of Good's Syndrome (Immunodeficiency with Thymoma)

Immunodeficiency with thymoma was described by R.A. Good in 1954 and is also named after him. The syndrome is characterized by hypogammaglobulinemia associated with thymoma and recurrent infections, bacterial but also viral, fungal and parasitic. Autoimmune diseases, mainly pure red cell aplasia, other hematological disorders and erosive lichen planus are a common finding. We describe here a typical case exhibiting all these clinical features and report a detailed immunophenotypic assessment, as well as the positivity for autoantibodies against three cytokines (IFN-alpha, IL-6 and GM-CSF), which may add to known immune abnormalities. A review of the published literature, based on case series and immunological studies, offers some hints on the still unsolved issues of this rare condition.

Good's Syndrome: Time to Move on From Reviewing the Past

For seven decades, the pathophysiology of Good’s syndrome (GS) has remained a mystery, with few attempts to solve it. Initially described as an association between hypogammaglobulinemia and thymoma, controversy exists whether this is a unique disease, or a subgroup of Common Variable Immune Deficiency (CVID). Recently, some distinguishing aspects of both syndromes have come to light reflecting fundamental differences in their underlying pathophysiology. GS and CVID differ in demographic features and immune phenotype. GS is found almost exclusively in adults and is characterized by a significantly reduced or absence of peripheral B cells. In CVID, which also occurs in children, most patients have normal or slightly reduced peripheral B cells, with a distinguishing feature of low memory B cells. Similarly, differences in T cell dysregulation and manifestations of hematologic cytopenias may further distinguish GS from CVID. Knowledge of the clinical phenotype of this rare adult immune deficiency stems from individual case reports, retrospective, and cross-sectional data on a few cohorts with a limited number of well characterized patients. The understanding of pathophysiology in GS is hampered by the incomplete and inconsistent reporting of clinical and laboratory data, with a limited knowledge of its natural history. In this mini review, we discuss current state of the art data and identify research gaps. In order to resolve controversies and fill in knowledge gaps, we propose a coordinated paradigm shift from incidence reporting to robust investigative studies, addressing mechanisms of disease. We hope this novel approach sets a clear direction to solve the current controversies.

When the Good Syndrome Goes Bad: A Systematic Literature Review

Background

Good syndrome is a rare adult-onset immunodeficiency characterized by thymoma and hypogammaglobulinemia. Its clinical manifestations are highly heterogeneous, ranging from various infections to autoimmunity.

Objective

This study was to summarize patient characteristics, identify prognostic factors and define clinical subgroups of Good syndrome.

Methods

A systematic literature review was conducted to include patients with Good syndrome identified in PubMed, Embase and Cochrane databases between January 2010 and November 2020. Logistic and Cox regressions were used to identify prognostic factors impacting outcomes. Clinical subgroups were defined by multiple correspondence analysis and unsupervised hierarchical clustering. A decision tree was constructed to characterize the subgroup placement of cases.

Results

Of 162 patients included in the current study, the median age at diagnosis was 58 years and 51% were male. Type AB was the most common histological subtype of thymoma, and infections as well as concurrent autoimmune disorders were identified in 92.6% and 51.2% patients, respectively. Laboratory workup showed typical findings of combined immunodeficiency. Thymoma status (odds ratio [OR] 4.157, confidence interval [CI] 1.219-14.177, p = 0.023), infections related to cellular immunity defects (OR 3.324, 95% CI 1.100-10.046, p = 0.033), infections of sinopulmonary tract (OR 14.351, 95% CI 2.525-81.576, p = 0.003), central nerve system (OR 6.403, 95% CI 1.205-34.027, p = 0.029) as well as bloodstream (OR 6.917, 95% CI 1.519-31.505, p = 0.012) were independent prognostic factors. The 10-year overall survival was 53.7%. Cluster analysis revealed three clinical subgroups with distinct characteristics and prognosis (cluster 1, infections related to cellular immunity defects; cluster 2, infections related to other immunity defects; cluster 3, infections related to humoral and phagocytic immunity defects). A decision tree using infection types (related to humoral and cellular immunity defects) could place patients into corresponding clusters with an overall correct prediction of 72.2%.

Conclusions

Infection type and site were the main prognostic factors impacting survival of patients with Good syndrome. We identified three subgroups within Good syndrome associated with distinct clinical features, which may facilitate the study of underlying pathogenesis as well as development of targeted therapy.

Prognosis of Good syndrome: mortality and morbidity of thymoma associated immunodeficiency in perspective

Good syndrome (GS) or thymoma-associated immunodeficiency, is a rare condition that has only been studied in retrospective case series. General consensus was that GS has a worse prognosis than other humoral immunodeficiencies. In this study, physicians of GS patients completed two questionnaires with a two year interval with data on 47 patients, 499 patient years in total. Results on epidemiology, disease characteristics, and outcome are presented. Mean age at diagnosis was 60years and median follow-up from onset of symptoms was 9years. There was a high frequency of respiratory tract infections due to encapsulated bacteria. Median survival was 14years. Survival was reduced compared to age-matched population controls (5-year survival: 82% versus 95%, p=0.008). In this cohort survival was not associated with gender (HR 0.9, 95% CI 0.3-3.0), autoimmune diseases (HR 2.9, 95% CI 0.8-10.1) or immunosuppressive use (HR 0.3, 95% CI: 0.1-1.2).

Humoral Immunity in Bronchiectasis: Finding Good's Syndrome

We present a case of a 37-year-old man with a past history of a surgically removed thymoma, who presented with recurrent pulmonary infections and bronchiectasis. On further testing, he was found to have low total immunoglobulin levels, a constellation of findings known as Good's syndrome. He responded well to immunoglobulin replacement, in addition to the usual treatments for bronchiectasis. We present this case to emphasize the association of bronchiectasis, low immunoglobulins, and thymomas and the role of immunoglobulin replacement as a treatment option.

Genetic polymorphisms of innate and adaptive immunity as predictors of outcome in critically ill patients

Sepsis and septic shock frequently cause the admission or complicate the clinical course of critically ill patients admitted in the intensive care units (ICU). Genetic variations disrupting the immune sensing of infectious organisms, could affect the ability of the immune system to respond to infection, and may influence both the genetic predisposition to infection and the diversity of the clinical presentation of sepsis. The aim of this study was to uncover possible associations between common functional immune gene polymorphisms (of both innate and adaptive immunity) and ICU-acquired sepsis and mortality. The TLR4-D299G (rs4986790), TLR4-T399I (rs4986791), C2-c.841_849+19del28 (rs9332736), TACI-C104R (rs34557412), BAFFR-P21R (rs77874543), and BAFFR-H159Y (rs61756766) polymorphisms were detected in a cohort of 215 critically ill patients, admitted in an 8-bed medical/surgical ICU. Interestingly, TLR4-D299G, TLR4-T399I and BAFFR-P21R carriage was associated with a lower risk of ICU-acquired sepsis. This association applied particularly in medical patients, while in trauma and surgical patients no significant associations were observed. Moreover, carriers of TACI-C104R displayed an undiagnosed mild to moderate hypogammaglobulinemia along with a significantly lower survival rate in the ICU, although lethal events were not attributed to sepsis. These findings further elucidate the role that host immune genetic variations may play in the susceptibility to ICU-acquired sepsis and ICU mortality.

Heterozygous alterations of TNFRSF13B/TACI in tonsillar hypertrophy and sarcoidosis

TNFRSF13B/TACI defects have been associated with CVID pathogenesis and/or phenotype, especially the development of benign lymphoproliferation and autoimmunity. Our purpose was to investigate the role of TNFRSF13B/TACI defects in the pathogenesis of two common lymphoproliferative disorders, namely, sarcoidosis and tonsillar hypertrophy (TH). 105 patients (71 with sarcoidosis and 34 with TH, including 19 without infectious causative and 15 due to Haemophilus influenzae) were analyzed for TNFRSF13B/TACI defects. Two out of 19 TH patients without infectious cause (10.5%) and 2 patients with sarcoidosis (2.8%) displayed rare TNFRSF13B/TACI defects (I87N, L69TfsX12, E36L, and R202H, resp.). Both mutations identified in TH patients have been assessed as deleterious for protein function, while the patient with the R202H mutation and sarcoidosis exhibited also sIgG4D. Our study further supports the notion that TNFRSF13B/TACI defects alone do not result in CVID but may be also found frequently in distinct clinical phenotypes, including benign lymphoproliferation and IgG subclass deficiencies.

Good's syndrome and IgA monoclonal gammopathy of undetermined significance

Characterised by the association of a thymoma, hypogammaglobulinaemia, and B-cell and T-cell dysfunction, Good's syndrome (GS) is a rare cause of adult immunodeficiency leading to recurrent infections, and autoimmune manifestations related to the thymoma. We describe a 70-year-old woman in whom the diagnosis of GS was made after 7 years follow-up of a monoclonal gammopathy of undetermined significance (MGUS). After thymectomy, she received monthly intravenous immunoglobulin perfusions in order to maintain a normal plasmatic IgG level. To our knowledge, this is the fifth described case of GS associated with an MGUS. This rare condition should not be misdiagnosed, as the prognosis is determined by infectious and autoimmune complications, which could be prevented.