Factors Beyond Lack of Antibody Govern Pulmonary Complications in Primary Antibody Deficiency

Pulmonary Computed Tomography Screening Frequency in Primary Antibody Deficiency

BACKGROUND

Patients with primary antibody deficiency (PAD) frequently suffer from pulmonary complications, associated with severe morbidity and mortality. Hence, regular pulmonary screening by computed tomography (CT) scanning is advised. However, predictive risk factors for pulmonary morbidity are lacking.

OBJECTIVE

To identify patients with PAD at risk for pulmonary complications necessitating regular CT screening.

METHODS

A retrospective, longitudinal cohort study of patients with PAD (median follow-up 7.4 [2.3-14.8] years) was performed. CTs were scored using the modified Brody-II scoring system. Clinical and laboratory parameters were retrospectively collected. Potential risk factors were identified by univariate analysis when P < .2 and confirmed by multivariable logistic regression when P < .05.

RESULTS

The following independent risk factors for progression of airway disease (AD) were identified: (1) diagnosis of X-linked agammaglobulinemia (XLA), (2) recurrent airway infections (2.5/year), and (3) the presence of AD at baseline. Signs of AD progression were detected in 5 of 11 patients with XLA and in 17 of 80 of the other patients with PAD. Of the 22 patients who progressed, 17 had pre-existent AD scores ≥7.0%. Increased AD scores were related to poorer forced expiratory volume in 1 second values and chronic cough. Common variable immunodeficiency and increased CD4 effector/memory cells were risk factors for an interstitial lung disease (ILD) score ≥13.0%. ILD ≥13.0% occurred in 12 of 80 patients. Signs of ILD progression were detected in 8 of 80 patients, and 4 of 8 patients showing progression had pre-existent ILD scores ≥13.0%.

CONCLUSION

We identified risk factors that distinguished patients with PAD at risk for AD and ILD presence and progression, which could guide future screening frequency; however, independent and preferably prospective validation is needed.

Multiple-breath washout to detect lung disease in patients with inborn errors of immunity

Background

Pulmonary manifestations are the major cause of morbidity and mortality in patients with inborn errors of immunity (IEI). New and more sensitive diagnostic methods can potentially lead to earlier recognition and treatment of IEI lung disease and improve outcome. The aim of this study was to compare multiple-breath washout (MBW) and spirometry in patients with IEI and cystic fibrosis (CF) as well as healthy controls (HC) and to evaluate the sensitivity of lung clearance index (LCI) to assess lung disease in IEI.

Methods

IEI patients (n=114) were recruited from our paediatric and adult immunodeficiency outpatient clinics and compared to age-matched CF patients (n=114) and HC (n=114). MBW measurements and spirometry were performed in the study participants, and MBW testing was repeated after 63-707 days in IEI patients (n=70).

Results

The LCI was significantly higher in IEI patients than in HC (p<0.001) and significantly lower than in CF patients (p<0.001). The forced expiratory volume in 1 s (FEV1) z-score was significantly lower in IEI patients than in HC (p<0.01) and significantly higher than in CF patients (p<0.01). LCI and FEV1 z-score correlated moderately negatively in the total cohort, the IEI group and the CF group. Nineteen (20.7%) of 92 IEI patients and 35 (33.3%) of 105 CF patients had an elevated LCI but a normal FEV1 z-score. After a median of 364 days, the median LCI of 70 IEI patients increased significantly by 0.2.

Conclusion

MBW is useful to detect lung disease in IEI and is more sensitive than spirometry.

IgD+IgM- B Cells in Common Variable Immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent form of primary hypogammaglobulinemia in adults. In addition to recurrent infections and respiratory manifestations, CVID patients may present several non-infection complications such as autoimmune diseases. The mechanisms that lead to immune dysregulation in CVID are not completely understood. Given the role of IgD on naïve B cells in the maintenance of tolerance and secreted IgD in the respiratory mucosa, we evaluated the frequency of IgD+ naïve and IgD+ memory B cells in CVID patients. Here, no differences were observed in the percentages and proliferative responses of anergic IgD+IgM-CD27- B cells between CVID patients, with or without autoimmune disease, and the control group. Interestingly, in the compartment of memory B cells, the percentage of IgD+IgM- cells was higher only in CVID patients with allergic rhinitis/allergic asthma. Our results may indicate that anergic IgD+IgM-CD27- B cells may not be compromised in our CVID cohort. However, IgD+IgM- memory B cells may play a role in the immunopathogenesis of allergic rhinitis/allergic asthma in CVID patients. Further studies are needed to better understand the participation of IgD+IgM- memory B cells in the immunopathogenesis of allergic rhinitis/allergic asthma in CVID patients.

Interstitial lung diseases in inborn errors of immunity

PURPOSE OF REVIEW

Our goal is to review current understanding of interstitial lung disease (ILD) affecting patients with inborn errors of immunity (IEI). This includes understanding how IEI might predispose to and promote development or progression of ILD as well as how our growing understanding of IEI can help shape treatment of ILD in these patients. Additionally, by examining current knowledge of ILD in IEI, we hope to identify key knowledge gaps that can become focus of future investigative efforts.

RECENT FINDINGS

Recent identification of novel IEI associated with ILD and the latest reports examining treatment of ILD in IEI are included. Of noted interest, are recent clinical studies of immunomodulatory therapy for ILD in common variable immunodeficiency.

SUMMARY

ILD is a frequent complication found in many IEI. This article provides a guide to identifying manifestations of ILD in IEI. We review a broad spectrum of IEI that develop ILD, including antibody deficiency and immune dysregulation disorders that promote autoimmunity and autoinflammation. This work integrates clinical information with molecular mechanisms of disease and diagnostic assessments to provide an expedient overview of a clinically relevant and expanding topic.

Endotypes in bronchiectasis: moving towards precision medicine. A narrative review

Bronchiectasis is a highly complex entity that can be very challenging to investigate and manage. Patients are diverse in their aetiology, symptoms, risk of complications and outcomes. "Endotypes"- subtypes of disease with distinct biological mechanisms, has been proposed as a means of better managing bronchiectasis. This review discusses the emerging field of endotyping in bronchiectasis. We searched PubMed and Google Scholar for randomized controlled trials (RCT), observational studies, systematic reviews and meta-analysis published from inception until October 2022, using the terms: "bronchiectasis", "endotypes", "biomarkers", "microbiome" and "inflammation". Exclusion criteria included commentaries and non-English language articles as well as case reports. Duplicate articles between databases were initially identified and appropriately excluded. Studies identified suggest that it is possible to classify bronchiectasis patients into multiple endotypes deriving from their co-morbidities or underlying causes to complex infective or inflammatory endotypes. Specific biomarkers closely related to a particular endotype might be used to determine response to treatment and prognosis. The most clearly defined examples of endotypes in bronchiectasis are the underlying causes such as immunodeficiency or allergic bronchopulmonary aspergillosis where the underlying causes are clearly related to a specific treatment. The heterogeneity of bronchiectasis extends, however, far beyond aetiology and it is now possible to identify subtypes of disease based on inflammatory mechanisms such airway neutrophil extracellular traps and eosinophilia. In future biomarkers of host response and infection, including the microbiome may be useful to guide treatments and to increase the success of randomized trials. Advances in the understanding the inflammatory pathways, microbiome, and genetics in bronchiectasis are key to move towards a personalized medicine in bronchiectasis.

Respiratory Comorbidities Associated with Bronchiectasis in Patients with Common Variable Immunodeficiency in the USIDNET Registry

BACKGROUND

Bronchiectasis is a major respiratory complication in patients with common variable immunodeficiency (CVID) and is associated with recurrent pulmonary infections. However, it is unclear whether other infections or non-infectious respiratory conditions are related to its development.

OBJECTIVE

To identify respiratory comorbidities associated with bronchiectasis in patients with CVID.

METHODS

A total of 1470 CVID patients enrolled in the USIDNET registry were included in a cross-sectional analysis. The primary outcome of our study was to determine the clinical characteristics and other respiratory conditions associated with respiratory comorbidities and physician-reported bronchiectasis.

RESULTS

One hundred ninety-seven CVID patients were noted to have bronchiectasis (13.4%). Affected patients were significantly older than patients without bronchiectasis (median age 54 years vs. 49 years, p = 0.0004). These patients also had lower serum IgA (13 mg/dL IQR 60 mg/dL vs. 28.4 mg/dL IQR 66 mg/dL, p = 0.000). Notably, chronic rhinosinusitis (OR = 1.69 95%CI 1.05-2.75), sinusitis (OR = 2.06 95%CI 1.38-3.09), pneumonia (OR = 2.70 95%CI 1.88-3.88), COPD (OR = 2.66 95%CI 1.51-4.67), and interstitial lung disease (OR = 2.34 95%CI 1.41-3.91) were independently associated with the development of bronchiectasis in this population.

CONCLUSION

These data suggest that lower and upper respiratory infections, chronic lower airway disease, and interstitial lung diseases are independently associated with bronchiectasis in CVID patients. Further study into predisposing conditions related to the development of bronchiectasis in CVID patients may allow prediction and early intervention strategies to prevent the development of this complication.

Current Issues in the Management of IgG Subclass Deficiencies in Adults With Chronic Respiratory Diseases

Primary immunodeficiency diseases (PIDs) are uncommon in adults; however, immunoglobulin G subclass deficiency (IGGSCD) is often found in a subset of adult patients with chronic respiratory diseases. As quantitative laboratory tests are used to diagnose IGGSCD, the clinical significance of IGGSCD remains controversial. However, respiratory infection is a common presenting feature of IGGSCD, and respiratory complications are responsible for subsequent morbidities, such as severe asthma, bronchiectasis, chronic obstructive airway diseases, and mortality. This review summarizes the current epidemiological data for PIDs, focusing on IGGSCD in the adult population. In addition, the investigation, treatment, and management strategies are detailed, including distinct issues faced by patients with chronic airway disease and their physicians in the proper diagnosis and treatment of IGGSCD.

Interstitial Lung Disease in Immunocompromised Children

BACKGROUND

The range of pulmonary complications beyond infections in pediatric immunocompromised patients is broad but not well characterized. Our goal was to assess the spectrum of disorders with a focus on interstitial lung diseases (ILD) in immunodeficient patients.

METHODS

We reviewed 217 immunocompromised children attending a specialized pneumology service during a period of 23 years. We assigned molecular diagnoses where possible and categorized the underlying immunological conditions into inborn errors of immunity or secondary immunodeficiencies according to the IUIS and the pulmonary conditions according to the chILD-EU classification system.

RESULTS

Among a wide array of conditions, opportunistic and chronic infections were the most frequent. ILD had a 40% prevalence. Of these children, 89% had a CT available, and 66% had a lung biopsy, which supported the diagnosis of ILD in 95% of cases. Histology was often lymphocyte predominant with the histo-pattern of granulomatous and lymphocytic interstitial lung disease (GLILD), follicular bronchiolitis or lymphocytic interstitial pneumonitis. Of interest, DIP, PAP and NSIP were also diagnosed. ILD was detected in several immunological disorders not yet associated with ILD.

CONCLUSIONS

Specialized pneumological expertise is necessary to manage the full spectrum of respiratory complications in pediatric immunocompromised patients.

Bronchiectasis and obstructive lung diseases in primary antibody deficiencies and beyond: update on management and pathomechanisms

PURPOSE OF REVIEW

Pulmonary complications are among the most frequent manifestations in patients with primary antibody deficiency (PAD), contributing significantly to morbidity and mortality. Here, we focus on recent findings in obstructive pulmonary disease and bronchiectasis in PAD. Since specific data on patients with PAD is limited and management mostly follows general recommendations, this review also aims to summarize data from the immunocompetent population.

RECENT FINDINGS

Potential risk factors for the development and progression of bronchiectasis include reduced immunoglobulins and lower CD4 cells. In addition, Pseudomonas aeruginosa and an altered microbiome might contribute to local inflammation and disease progression. Findings on the contribution of neutrophils and eosinophils in the affected immunocompetent population require confirmation in PAD. Despite its high global burden, there is an extreme paucity of data on chronic obstructive pulmonary disease in PAD. Lower IgA and IgM are associated with asthma in PAD, but the heterogeneity of prevalence among PAD groups is poorly understood. Recent observations of non-IgE-mediated pathomechanisms in asthma may be of particular interest in PAD patients.

SUMMARY

Management of PAD patients with chronic lung disease requires a multidisciplinary team approach including immunology, pulmonology, infectious disease and physiotherapy. Diagnostic processes should be harmonized to ensure a more precise perspective on prevalence and disease courses.

Comparison of pulmonary lesions using lung ultrasound and high-resolution computed tomography in adult patients with primary humoral immunodeficiencies

Pulmonary involvement is the most common complication in patients with predominantly antibody deficiencies (PADs). Therefore, patients require repeated imaging tests. Unlike high-resolution computed tomography (HRCT), lung ultrasonography (LUS) does not expose patients to X-rays or contrast agents, and can be performed even at the bedside. This study aimed to evaluate lung lesions using simultaneous LUS and HRCT in a group of patients with PADs. Twenty-nine adult patients (13 women and 16 men) diagnosed with PADs according to the ESID criteria (23 Common variable immunodeficiency, 2 X-linked agammaglobulinemia, 2 IgG subclass deficiencies, and 2 Unspecified hypogammaglobulinemia) were included in the study. The mean age was 39.0 ± 11.9 years. The mean time elapsed between the first symptoms of PADs and the examination was 15.4 ± 10.1 years. Lung ultrasonography and high-resolution computed tomography were performed simultaneously according to a defined protocol during the clinic visits. In both examinations, lesions were compared in the same 12 regions: for each lung in the upper, middle, and lower parts, separately, front and back. A total of 435 lesions were described on LUS, whereas 209 lesions were described on HRCT. The frequencies of lesions in the lung regions were similar between LUS and HRCT. In both examinations, lesions in the lower parts of the lungs were most often reported (LUS 60.9% vs. HRCT 55.5%) and least often in the upper parts of the lungs (LUS 12.7% vs. HRCT 12.0%). The most frequently described lesions were LUS consolidations (99; 22.8%) and HRCT fibrosis (74; 16.5%). A statistically significant relationship was found in the detection of fibrosis in 11 of the 12 regions (phi = 0.4-1.0). Maximum values of the phi coefficient for the upper part of the left lung were recorded. Compared with HRCT, LUS is an effective alternative for evaluating and monitoring pulmonary lesions in adult patients with PADs, especially for pulmonary fibrosis.

Clinical and genetic findings in two siblings with X-Linked agammaglobulinemia and bronchiolitis obliterans: a case report

Background

X-linked agammaglobulinemia (XLA) is an Inborn Errors of Immunity (IEI) characterized by pan-hypogammaglobulinemia and low numbers of B lymphocytes due to mutations in BTK gene. Usually, XLA patients are not susceptible to respiratory tract infections by viruses and do not present interstitial lung disease (ILD) such as bronchiolitis obliterans (BO) as a consequence of acute or chronic bacterial infections of the respiratory tract. Although many pathogenic variants have already been described in XLA, the heterogeneous clinical presentations in affected patients suggest a more complex genetic landscape underlying this disorder.

Case presentation

We report two pediatric cases from male siblings with X-Linked Agammaglobulinemia and bronchiolitis obliterans, a phenotype not often observed in XLA phenotype. The whole-exome sequencing (WES) analysis showed a rare hemizygous missense variant NM_000061.2(BTK):c.1751G>A(p.Gly584Glu) in BTK gene of both patients. We also identified a gain-of-function mutation in TGFβ1 (rs1800471) previously associated with transforming growth factor-beta1 production, fibrotic lung disease, and graft fibrosis after lung transplantation. TGFβ1 plays a key role in the regulation of immune processes and inflammatory response associated with pulmonary impairment.

Conclusions

Our report illustrates a possible role for WES in patients with known inborn errors of immunity, but uncommon clinical presentations, providing a personalized understanding of genetic basis, with possible implications in the identification of potential treatments, and prognosis for patients and their families.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03245-x.

Convergence of cytokine dysregulation and antibody deficiency in common variable immunodeficiency with inflammatory complications

BACKGROUND

Noninfectious complications are the greatest cause of morbidity and mortality in common variable immunodeficiency (CVID), but their pathogenesis remains poorly defined.

OBJECTIVE

Using high-throughput approaches, we aimed to identify, correlate, and determine the significance of immunologic features of CVID with noninfectious complications (CVIDc).

METHODS

We simultaneously applied proteomics, RNA sequencing, and mass cytometry to a large cohort with primary antibody deficiency.

RESULTS

CVIDc is differentiated from uncomplicated CVID, other forms of primary antibody deficiency, and healthy controls by a distinct plasma proteomic profile. In addition to confirming previously reported elevations of 4-1BB, IL-6, IL-18, and IFN-γ, we found elevations of colony-stimulating factor 1, IL-12p40, IL-18R, oncostatin M, TNF, and vascular endothelial growth factor A to differentiate CVIDc. This cytokine dysregulation correlated with deficiency of LPS-specific antibodies and increased soluble CD14, suggesting microbial translocation. Indicating potential significance of reduced LPS-specific antibodies and resultant microbial-induced inflammation, CVIDc had altered LPS-induced gene expression matching plasma proteomics and corresponding with increased CD14⁺CD16^- monocytes, memory T cells, and tissue inflammation ameliorated by T-cell-targeted therapy. Unsupervised machine learning accurately differentiated subjects with CVIDc and supported cytokine dysregulation, antibody deficit, and T-cell activation as defining and convergent features.

CONCLUSIONS

Our data expand understanding of CVIDc proteomics, establish its link with deficiency of IgA and LPS-specific antibodies, and implicate altered LPS-induced gene expression and elevated monocytes and T cells in this cytokine dysregulation. This work indicates that CVIDc results when insufficient antibody neutralization of pathogen-associated molecular patterns, like LPS, occurs in those with a heightened response to these inflammatory mediators, suggesting a 2-hit model of pathogenesis requiring further exploration.

The pediatric common variable immunodeficiency - from genetics to therapy: a review

Common variable immunodeficiency (CVID) is the most prevalent antibody deficiency, characterized by remarkable genetic, immunological, and clinical heterogeneity. The diagnosis of pediatric CVID is challenging due to the immaturity of the immune response and sustained actively developing antibody affinity to antigens and immunological memory that may overlap with the inborn error of immunity. Significant progress has been recently done in the field of immunogenetics, yet a paucity of experimental and clinical studies on different systemic manifestations and immunological features of CVID in children may contribute to a delayed diagnosis and therapy. In this review, we aimed at defining the variable epidemiological, etiological, and clinical aspects of pediatric CVID with special emphasis on predominating infectious and non-infectious phenotypes in affected children.

CONCLUSION

While pediatric CVID is a multifaceted and notorious disease, increasing the pediatricians' awareness of this disease entity and preventing the diagnostic and therapeutic delay are needed, thereby improving the prognosis and survival of pediatric CVID patients.

WHAT IS KNOWN

• CVID is an umbrella diagnosis characterized by complex pathophysiology with an antibody deficiency as a common denominator. • It is a multifaceted disease characterized by marked genetic, immunological, and clinical heterogeneity..

WHAT IS NEW

• The diagnosis of pediatric CVID is challenging due to the immaturity of innate and adaptive immune response. • Increasing the pediatricians' awareness of CVID for the early disease recognition, timely therapeutic intervention, and improving the prognosis is needed.

Lymphoid malignancy in common variable immunodeficiency in a single-center cohort

One of the complications of common variable immunodeficiency (CVID) is the development of lymphoid malignancy. In this retrospective, single-center study of 647 CVID subjects followed over 4 decades, we present immunologic and clinical phenotypes, pathology, treatment, and outcomes of 45 patients (15 males and 30 females, 7%) who developed 49 lymphoid malignancies. The mean age at CVID diagnosis was 42.6 years) and at lymphoma diagnosis was 48.8 years. Of the 41 with known follow up, 29 (70%) have died, 27 of these due to this diagnosis. Twelve are alive, in remission or have achieved cure; four others were alive at last encounter. Some patients had a history of only recurrent infections (36.3%); others had autoimmunity (33%), enteropathy (20%), and/or granulomatous disease (11%). Six had previously been treated for another cancer. This report also includes 6 additional living CVID patients who had been diagnosed with NHL; 4 were given treatment for this. However, on pathology review, the initial diagnosis was reversed, as the findings were more consistent with a benign lymphoproliferative process. This study outlines the high incidence of lymphoma in this single CVID cohort, and some of the diagnostic challenges presented due to immune dysregulation characteristic of this immune defect.

Common Variable Immunodeficiency and Other Immunodeficiency Syndromes in Bronchiectasis

Immunodeficiency represents a vast number of diseases and syndromes. Both primary and secondary forms of immunodeficiency are important contributors to the development of bronchiectasis. Primary immune deficiencies, in particular, are increasingly identified and defined as contributors. Specific immune deficiencies that are closely associated with bronchiectasis and as discussed in this article are common variable immunodeficiency, specific antibody deficiency, immunodeficiencies involving immunoglobulin E, DOCK8 immunodeficiency, phosphoglucomutase 3 deficiency, activated phosphoinositide 3-kinase delta syndrome, and X-linked agammaglobulinemia. Each of these primary immune deficiencies has unique nuances. Vigilance for these unique signs and symptoms is likely to improve recognition of specific immunodeficiency in the idiopathic bronchiectasis patient. Secondary forms of immunodeficiency occur as a result of a separate disease process. Graft versus host disease, malignancy, and human immunodeficiency virus are three classic examples discussed in this article. An awareness of the potential for these disease settings to lead to bronchiectasis is necessary to optimize patient care. With understanding and mindfulness toward the intricate relationship between bronchiectasis and immunodeficiency, there is an opportunity to elucidate pathophysiologic underpinnings between these two syndromes.

Shared Pathogenetic Features Between Common Variable Immunodeficiency and Sjögren's Syndrome: Clues for a Personalized Medicine

Common variable immunodeficiency disorders (CVID) are a group of rare diseases of the immune system and the most common symptomatic primary antibody deficiency in adults. The “variable” aspect of CVID refers to the approximately half of the patients who develop non-infective complications, mainly autoimmune features, in particular organ specific autoimmune diseases including thyroiditis, and cytopenias. Among these associated conditions, the incidence of lymphoma, including mucosal associated lymphoid tissue (MALT) type, is increased. Although these associated autoimmune disorders in CVID are generally attributed to Systemic Lupus Erythematosus (SLE), we propose that Sjogren’s syndrome (SS) is perhaps a better candidate for the associated disease. SS is an autoimmune disorder characterized by the lymphocytic infiltrates of lacrimal and salivary glands, leading to dryness of the eyes and mouth. Thus, it is a lymphocyte aggressive disorder, in contrast to SLE where pathology is generally attributed to auto-antibody and complement activation. Although systemic lupus erythematosus (SLE) shares these features with SS, a much higher frequency of MALT lymphoma distinguishes SS from SLE. Also, the higher frequency of germ line encoded paraproteins such as the monoclonal rheumatoid factor found in SS patients would be more consistent with the failure of B-cell VDJ switching found in CVID; and in contrast to the hypermutation that characterizes SLE autoantibodies. Thus, we suggest that SS may fit as a better “autoimmune” association with CVID. Examining the common underlying biologic mechanisms that promote lymphoid infiltration by dysregulated lymphocytes and lymphoma in CVID may provide new avenues for treatment in both the diseases. Since the diagnosis of SLE or rheumatoid arthritis is usually based on specific autoantibodies, the associated autoimmune features of CVID patients may not be recognized in the absence of autoantibodies.

State-of-the-art diagnostic evaluation of common variable immunodeficiency

OBJECTIVE

To summarize the current understanding of diagnostic and postdiagnostic evaluation of common variable immunodeficiency (CVID).

DATA SOURCES

PubMed Central database.

STUDY SELECTIONS

Original research articles and review articles from 2015 to 2020 including seminal articles that shaped the diagnostic and postdiagnostic evaluation of CVID were incorporated. This work focuses on initial diagnosis of CVID, genetic evaluations, and postdiagnostic assessment of respiratory, gastrointestinal, and hepatobiliary diseases including spleen and lymph node enlargement.

RESULTS

CVID presents not only with frequent infections but also with noninfectious complications such as autoimmunity, gastrointestinal disease, chronic lung disease, granulomas, liver disease, lymphoid hyperplasia, splenomegaly, or malignancy. The risk of morbidity and mortality is higher in patients with CVID and noninfectious complications. Detailed diagnostic approaches, which may incorporate genetic testing, can aid characterization of individual CVID cases and shape treatment in some instances. Moreover, continued evaluation after CVID diagnosis is key to optimal management of this complex disorder. These postdiagnostic evaluations include pulmonary function testing, radiologic studies, and laboratory evaluations that may be conducted at frequencies determined by disease activity.

CONCLUSION

Although the diagnosis can be achieved similarly in all patients with CVID, those with noninfectious complications have distinct concerns during clinical evaluation. State-of-the-art workup of CVID with noninfectious complications typically includes genetic analysis, which may shape precision therapy, and thoughtful application of postdiagnostic tests that monitor the presence and progression of disease in the myriad of tissues that may be affected. Even with recent advancements, knowledge gaps in diagnosis, prognosis, and treatment of CVID persist, and continued research efforts are needed.

Interstitial Lung Disease in Common Variable Immunodeficiency

Interstitial lung disease (ILD) is a common complication in patients with common variable immunodeficiency (CVID) and often associated with other features, such as bronchiectasis and autoimmunity. As the ILD term encompasses different acute and chronic pulmonary conditions, the diagnosis is commonly made based on imaging features; histopathology is less frequently available. From a cohort of 637 patients with CVID followed at our center over 4 decades, we reviewed the data for 46 subjects (30 females, 16 males) who had lung biopsies with proven ILD. They had a median age at CVID diagnosis of 26 years old, with a median IgG level at diagnosis of 285.0 mg/dL with average isotype switched memory B cells of 0.5%. Lung biopsy pathology revealed granulomas in 25 patients (54.4%), lymphoid interstitial pneumonia in 13 patients (28.3%), lymphoid hyperplasia not otherwise specified in 7 patients (15.2%), cryptogenic organizing pneumonia in 7 patients (15.2%), follicular bronchitis in 4 patients (8.7%), and predominance of pulmonary fibrosis in 4 patients (8.7%). Autoimmune manifestations were common and were present in 28 (60.9%) patients. Nine patients (19.6%) died, with a median age at death of 49-years-old. Lung transplant was done in 3 of these patients (6.5%) who are no longer alive. These analyses reveal the high burden of this complication, with almost one-fifth of the group deceased in this period. Further understanding of the causes of the development and progression of ILD in CVID patients is required to define the best management for this patient population.

B Cell Dysregulation in Common Variable Immunodeficiency Interstitial Lung Disease

Common variable immunodeficiency (CVID) is the most frequently diagnosed primary antibody deficiency. About half of CVID patients develop chronic non-infectious complications thought to be due to intrinsic immune dysregulation, including autoimmunity, gastrointestinal disease, and interstitial lung disease (ILD). Multiple studies have found ILD to be a significant cause of morbidity and mortality in CVID. Yet, the precise mechanisms underlying this complication in CVID are poorly understood. CVID ILD is marked by profound pulmonary infiltration of both T and B cells as well as granulomatous inflammation in many cases. B cell depletive therapy, whether done as a monotherapy or in combination with another immunosuppressive agent, has become a standard of therapy for CVID ILD. However, CVID is a heterogeneous disorder, as is its lung pathology, and the precise patients that would benefit from B cell depletive therapy, when it should administered, and how long it should be repeated all remain gaps in our knowledge. Moreover, some have ILD recurrence after B cell depletive therapy and the relative importance of B cell biology remains incompletely defined. Developmental and functional abnormalities of B cell compartments observed in CVID ILD and related conditions suggest that imbalance of B cell signaling networks may promote lung disease. Included within these potential mechanisms of disease is B cell activating factor (BAFF), a cytokine that is upregulated by the interferon gamma (IFN-γ):STAT1 signaling axis to potently influence B cell activation and survival. B cell responses to BAFF are shaped by the divergent effects and expression patterns of its three receptors: BAFF receptor (BAFF-R), transmembrane activator and CAML interactor (TACI), and B cell maturation antigen (BCMA). Moreover, soluble forms of BAFF-R, TACI, and BCMA exist and may further influence the pathogenesis of ILD. Continued efforts to understand how dysregulated B cell biology promotes ILD development and progression will help close the gap in our understanding of how to best diagnose, define, and manage ILD in CVID.

Histology of Interstitial Lung Disease in Common Variable Immune Deficiency

Interstitial lung disease (ILD) is an important non-infectious complication in several primary immune deficiencies. In common variable immune deficiency (CVID) it is associated with complex clinical phenotypes and adverse outcomes. The histology of ILD in CVID is heterogeneous and mixed patterns are frequently observed within a single biopsy, including non-necrotising granulomatous inflammation, lymphoid interstitial pneumonitis, lymphoid hyperplasia, follicular bronchiolitis, organizing pneumonia, and interstitial fibrosis; ILD has to be differentiated from lymphoma. The term granulomatous-lymphocytic interstitial lung disease (GLILD), coined to describe the histopathological findings within the lungs of patients with CVID with or without multisystem granulomata, is somewhat controversial as pulmonary granulomata are not always present on histology and the nature of infiltrating lymphocytes is variable. In this mini review we summarize the literature on the histology of CVID-related ILD and discuss some of the factors that may contribute to the inter- and intra- patient variability in the histological patterns reported. Finally, we highlight areas for future development. In particular, there is a need for standardization of histological assessments and reporting, together with a better understanding of the immunopathogenesis of CVID-related ILD to resolve the apparent heterogeneity of ILD in this setting and guide the selection of rational targeted therapies in different patients.

Chronic Lung Disease in Primary Antibody Deficiency: Diagnosis and Management

Chronic lung disease is a complication of primary antibody deficiency (PAD) associated with significant morbidity and mortality. Manifestations of lung disease in PAD are numerous. Thoughtful application of diagnostic approaches is imperative to accurately identify the form of disease. Much of the treatment used is adapted from immunocompetent populations. Recent genomic and translational medicine advances have led to specific treatments. As chronic lung disease has continued to affect patients with PAD, we hope that continued advancements in our understanding of pulmonary pathology will ultimately lead to effective methods that alleviate impact on quality of life and survival.

The Importance of Primary Immune Deficiency Registries: The United States Immunodeficiency Network Registry

The importance of registries is vital for almost every human disease but crucial for rare disorders, where the centralized collection, organization, and quality check of data create a platform from where multiple analyses and scientific advances are possible. In this article, the authors review the creation of the United States Immunodeficiency Network registry, its role, and the numerous scientific achievements generated from the collective effort of many.

Bronchiectasis in Primary Antibody Deficiencies: A Multidisciplinary Approach

Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage.

Pulmonary Disease Burden in Primary Immune Deficiency Disorders: Data from USIDNET Registry

PURPOSE

Pulmonary manifestations are common in patients with primary immunodeficiency disorders (PIDs) but the prevalence, specific diseases, and their patterns are not well characterized.

METHODS

We conducted a retrospective analysis of pulmonary diseases reported in the database of the United States Immunodeficiency Network (USIDNET), a program of the Immune Deficiency Foundation. PIDs were categorized into 10 groups and their demographics, pulmonary diagnoses and procedures, infections, prophylaxis regimens, and laboratory findings were analyzed.

RESULTS

A total of 1937 patients with various PIDs (39.3% of total patients, 49.6% male, average age 37.9 years (SD = 22.4 years)) were noted to have a pulmonary disease comorbidity. Pulmonary diseases were categorized into broad categories: airway (86.8%), parenchymal (18.5%), pleural (4.6%), vascular (4.3%), and other (13.9%) disorders. Common variable immune deficiency (CVID) accounted for almost half of PIDs associated with airway, parenchymal, and other pulmonary disorders. Pulmonary procedures performed in 392 patients were mostly diagnostic (77.3%) or therapeutic (16.3%). These patients were receiving a wide variety of treatments, which included immunoglobulin replacement (82.1%), immunosuppressive (32.2%), anti-inflammatory (12.7%), biologic (9.3%), and cytokine (7.6%)-based therapies. Prophylactic therapy was being given with antibiotics (18.1%), antifungal (3.3%), and antiviral (2.2%) medications, and 7.1% of patients were on long-term oxygen therapy due to advanced lung disease.

CONCLUSIONS

Pulmonary manifestations are common in individuals with PID, but long-term pulmonary outcomes are not well known in this group of patients. Further longitudinal follow-up will help to define long-term prognosis of respiratory comorbidities and optimal treatment modalities.

Current Understanding and Recent Developments in Common Variable Immunodeficiency Associated Autoimmunity

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary immunodeficiency and comprises a group of disorders with similar antibody deficiency but a myriad of different etiologies, most of which remain undefined. The variable aspect of CVID refers to the approximately half of patients who develop non-infectious complications in addition to heightened susceptibility to infection. The pathogenesis of these complications is poorly understood and somewhat counterintuitive because these patients that are defined by their immune futility simultaneously have elevated propensity for autoimmune disease. There are numerous aspects of immune dysregulation associated with autoimmunity in CVID that have only begun to be studied. These findings include elevations of T helper type 1 and follicular helper T cells and B cells expressing low levels of CD21 as well as reciprocal decreases in regulatory T cells and isotype-switched memory B cells. Recently, advances in genomics have furthered our understanding of the fundamental biology underlying autoimmunity in CVID and led to precision therapeutic approaches. However, these genetic etiologies are also associated with clinical heterogeneity and incomplete penetrance, highlighting the fact that continued research efforts remain necessary to optimize treatment. Additional factors, such as commensal microbial dysbiosis, remain to be better elucidated. Thus, while recent advances in our understanding of CVID-associated autoimmunity have been exciting and substantial, these current scientific advances must now serve as building blocks for the next stages of discovery.