Immunological and Clinical Phenotyping in Primary Antibody Deficiencies: a Growing Disease Spectrum

Reappraisal of IgG subclass deficiencies: a retrospective comparative cohort study

Objective

The aim of the present study was to investigate the clinical spectrum of IgG subclass deficiencies (IgGSDs) and assess the relative clinical significance of diagnosing each specific IgGSD disorder as compared to the common variable immunodeficiency (CVID).

Methods

The clinical spectrum and immunological findings from 96 patients, diagnosed with diverse IgGSDs, were retrospectively evaluated. Specific IgGSDs were compared with each other and a cohort of 270 patients with CVID.

Results

In comparison to CVID, recurrent lower respiratory tract infections (LRTIs) and bronchiectasis were rarer in IgGSDs, while recurrent mucocutaneous herpes simplex virus reactivations were more common. With respect to autoimmunity, IgGSDs were associated with arthritis, while autoimmune cytopenias were less frequently observed than in CVID. Among IgGSDs, herpes zoster was more common in IgG3SD. Arthritis was more prevalent in IgG1 + 3SD. Given its association with LRTI, splenomegaly, immune thrombocytopenic purpura, and the lower class-switched memory B-cell counts, IgG2 + 4SD is the IgGSD that rather resembles CVID.

Conclusions

Comparative evaluation of phenotypes and treatments of patients with IgGSDs and CVID reveals distinct features, suggesting the differential clinical significance of diagnosing IgGSDs. The differential clinical expressions of IgGSDs highlight the need for studying each IgGSD separately in order to optimize disorder-specific follow-up procedures and prophylactic anti-infective measures.

Management of a Patient with Cardiovascular Disease Should Include Assessment of Primary and Secondary Immunodeficiencies: Part 1-Primary Immunodeficiencies

BACKGROUND

Cardiovascular diseases are some of the most prevalent chronic diseases that generate not only high social but also economic costs. It is becoming increasingly crucial to take into account inborn errors of immunity (IEIs, formerly known as primary immunodeficiencies (PIDs)) and secondary immunodeficiencies (SIDs) in the diagnostic and therapeutic management of cardiac patients. The number of diseases classified as IEIs is on the rise, with a current total of 485. It is essential to pay attention not only to already confirmed conditions but also to symptoms suggestive of immunodeficiencies.

OBJECTIVES

The aim of this article is to present IEIs with cardiovascular symptoms that may cause or exacerbate cardiovascular disease, as well as diagnostic and therapeutic procedures.

RESULTS

It is becoming increasingly evident that immunodeficiencies can be responsible for certain cardiovascular conditions, their hastened progression, and difficulties in their control.

CONCLUSIONS

Early detection of deficiencies improves not only the quality and longevity of patients, but also allows for better control of cardiovascular diseases and even prevention of their occurrence.

Fecal microbiota transplantation in a patient with chronic diarrhea and primary and secondary immunodeficiency (common variable immunodeficiency and splenectomy)

The gut microbiota serves a crucial role in the development of host immunity. Immunocompromised patients are particularly vulnerable to dysbiosis not only by virtue of a defect in the immune system but also due to increased susceptibility to infection and multiple courses of antibiotic therapy. Fecal microbiota transplantation is by far the most effective option for restoring gastrointestinal homeostasis. However, it is contraindicated in patients with significant primary and secondary immunodeficiencies. This article presents the case of a 59-year-old patient with common variable immunodeficiency, after splenectomy at age 39 for primary immune thrombocytopenia, who manifested diarrhea of up to 10 stools per day accompanied by secondary malnutrition and cachexia. The patient was admitted to the hospital on multiple occasions due to this condition, with stool PCR tests confirming a HHV-5 (Cytomegalovirus, CMV) infection. Following the administration of valganciclovir, the patient's complaints diminished, although, upon cessation of the drug, the symptoms recurred. In addition, the patient had an intestinal infection with C. difficile etiology. Given that the patient's therapeutic options had been exhausted, after obtaining informed consent from the patient and approval from the bioethics committee to conduct a medical experiment, treatment of diarrhea was undertaken by fecal microbiota transplantation with the certified preparation Mbiotix HBI from the Human Biome Institute. The patient underwent two transplants, with a one-week interval between them. The initial procedure was performed using the endoscopic method, while the subsequent was conducted using the capsule method. Following the administration of the applied treatment, the patient's symptoms were successfully alleviated, and no adverse effects were observed. A microbiological analysis of the intestinal microbiota was conducted prior to and following transplantation via next-generation sequencing (NGS). No recurrence of symptoms was observed during the two-year follow-up period. To the best of our knowledge, this is the first fecal microbiota transplantation in an adult patient with primary and secondary immunodeficiency.

Primary Immunodeficiency: Specific antibody deficiency with normal IgG

Specific antibody deficiency (SAD) is a common primary immunodeficiency disorder that should be considered in older children and adults with recurrent and/or severe sinopulmonary infections. The diagnosis is characterized by inadequate antibody response to polysaccharide vaccine, specifically, pneumococcal, with normal responses to protein antigens and normal levels of serum immunoglobulins as well as immunoglobulin G (IgG) subclasses. The underlying mechanism for SAD is not completely elucidated. It is understood that young children have limited polysaccharide responsiveness, which develops with increased age. Due to this phenomenon, the consensus is that there is adequate immune maturity after age 2 years, which is the earliest for the SAD diagnosis to be established. There remains a lack of consensus on thresholds for polysaccharide nonresponse, and there are several commercial laboratories that measure a range of serotypes, with the recommendation for patients to have their diagnostic evaluation with serotype testing both before vaccination and after vaccination to be conducted by the same laboratory. Once a diagnosis has been made, the management of SAD is based on the clinical severity. Clinicians may consider prophylactic antibiotics as well as immunoglobulin replacement. These patients should be closely followed up, with the possibility of discontinuation of IgG replacement after 12 to 24 months. Children are more likely to demonstrate resolution of SAD than are adolescents and adults. Patients with SAD may also progress to a more severe immunodeficiency; therefore, continued monitoring remains a crucial principle of practice in the care of patients with SAD.

Oral Diseases as a Manifestation of Inborn Errors of Immunity

Oral findings such as inflammation, ulcerations, or lesions can indicate serious systemic diseases and should prompt suspicion of acquired chronic conditions or inborn errors of immunity (IEIs). Currently, there are approximately 500 disease entities classified as IEIs, with the list expanding annually. The awareness of the existence of such conditions is of paramount importance, as patients with these disorders frequently necessitate the utilization of enhanced diagnostic techniques. This is exemplified by patients with impaired antibody production, in whom conventional serological methods may prove to be undiagnostic. Patients with IEI may require distinct therapeutic approaches or antimicrobial prophylaxis throughout their lives. An accurate diagnosis and, more importantly, early identification of patients with immune deficiencies is crucial to ensure the quality and longevity of their lives. It is important to note that the failure to establish a proper diagnosis or to provide adequate treatment could also have legal implications for medical professionals. The article presents IEIs, which may manifest in the oral cavity, and their diagnosis alongside therapeutic procedures.

IL-1 receptor 1 signaling shapes the development of viral antigen-specific CD4+ T cell responses following COVID-19 mRNA vaccination

BACKGROUND

The innate immune cytokine interleukin (IL)-1 can affect T cell immunity, a critical factor in host defense. In a previous study, we identified a subset of human CD4+ T cells which express IL-1 receptor 1 (IL-1R1). However, the expression of such receptor by viral antigen-specific CD4+ T cells and its biological implication remain largely unexplored. This led us to investigate the implication of IL-1R1 in the development of viral antigen-specific CD4+ T cell responses in humans, including healthy individuals and patients with primary antibody deficiency (PAD), and animals.

METHODS

We characterized CD4+ T cells specific for SARS-CoV-2 spike (S) protein, influenza virus, and cytomegalovirus utilizing multiplexed single cell RNA-seq, mass cytometry and flow cytometry followed by an animal study.

FINDINGS

In healthy individuals, CD4+ T cells specific for viral antigens, including S protein, highly expressed IL-1R1. IL-1β promoted interferon (IFN)-γ expression by S protein-stimulated CD4+ T cells, supporting the functional implication of IL-1R1. Following the 2nd dose of COVID-19 mRNA vaccines, S protein-specific CD4+ T cells with high levels of IL-1R1 increased, likely reflecting repetitive antigenic stimulation. The expression levels of IL-1R1 by such cells correlated with the development of serum anti-S protein IgG antibody. A similar finding of increased expression of IL-1R1 by S protein-specific CD4+ T cells was also observed in patients with PAD following COVID-19 mRNA vaccination although the expression levels of IL-1R1 by such cells did not correlate with the levels of serum anti-S protein IgG antibody. In mice immunized with COVID-19 mRNA vaccine, neutralizing IL-1R1 decreased IFN-γ expression by S protein-specific CD4+ T cells and the development of anti-S protein IgG antibody.

INTERPRETATION

Our results demonstrate the significance of IL-1R1 expression in CD4+ T cells for the development of viral antigen-specific CD4+ T cell responses, contributing to humoral immunity. This provides an insight into the regulation of adaptive immune responses to viruses via the IL-1 and IL-1R1 interface.

FUNDING

Moderna to HJP, National Institutes of Health (NIH) 1R01AG056728 and R01AG055362 to IK and KL2 TR001862 to JJS, Quest Diagnostics to IK and RB, and the Mathers Foundation to RB.

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.

Primary antibody deficiency-associated arthritis shares features with spondyloarthritis and enteropathic arthritis

OBJECTIVE

The clinical spectrum of primary antibody deficiencies (PADs) and especially common variable immunodeficiency (CVID) includes various autoimmune disorders. We studied the prevalence and the features of articular rheumatic disease in a cohort of patient with PADs.

METHODS

In this retrospective cohort study, complete clinical data of 268 patients with PADs, mainly consisting of patients with CVID, visiting the immunology outpatient clinic of a German tertiary hospital between 2018 and 2021 were collected. Those included case history, physical examination, laboratory as well as radiological findings.

RESULTS

Inflammatory arthritis was diagnosed in 16.4% of studied patients and was significantly more common among patients with PAD-associated enteropathy (OR 13.39, p=0.0001), splenomegaly (OR 6.09, p=0.0001) or atopic diseases (OR 3.31, p=0.021). Given HLA-B27 status, the involvement of the axial skeleton and the presence of features, such as anterior uveitis, inflammatory bowel disease, psoriasis and/or dactylitis, 75% of studied patients fulfilled the Assessment of Spondyloarthritis International Society classification criteria.

CONCLUSION

PAD-associated arthritis frequently shares features with spondyloarthritis (SpA) and enteropathic arthritis. The latter may suggest the interconnected pathomechanisms of inflammatory arthritis in SpA and PADs.

Primary antibody deficiencies represent an underestimated comorbidity in asthma patients: efficacy of immunoglobulin replacement therapy in asthma control

OBJECTIVE

Primary antibody deficiencies (PAD) are an underestimated comorbidity in asthma and its treatment could improve disease control.

METHODS

a retrospective cohort of asthmatics, affected by IgG subclass deficiency or unclassified antibody deficiency and treated with low-dose intravenous immunoglobulin replacement therapy (IRT) was recruited. Demographic and clinical data, chest CT scan, blood eosinophils, atopy, chronic oral corticosteroid (OCS) therapy were evaluated at baseline. Asthma exacerbations, lower respiratory tract infections (LRTI), upper respiratory tract infections (URTI) and asthma-related hospitalizations were assessed after one and two years of IRT.

RESULTS

57 moderate-to-severe asthmatics were enrolled, mostly affected by T2 low asthma (39/57, 68.4%). After one year, IRT was effective in improving, irrespective of bronchiectasis, atopy, eosinophils and PAD type: 1) trough IgG (826.9 ± 221.3 vs 942.2 ± 195.1 mg/dl; p < 0.0001) and IgG subclasses (IgG1 355.4 ± 88.4 vs 466.7 ± 122.3, p < 0.0001; IgG2 300.1 ± 130.1 vs 347.6 ± 117.3, p < 0.0005) serum levels. 2) asthma exacerbations (6.4 ± 4.1 vs 2.4 ± 1.9, p < 0.0001), LRTI (4.3 ± 3.9 vs 1.3 ± 1.5, p < 0.0001) and hospitalization rate (0.26 ± 0.7 vs 0.05 ± 0.2, p < 0.01). These results persisted after 2 years of therapy. Estimated mean cumulative OCS exposure was reduced by 4500 mg over the 2-year period.

CONCLUSIONS

low-dose IRT is effective in improving asthma control and lessening OCS burden in asthmatics affected by PAD.

Defining Clinical and Immunological Predictors of Poor Immune Responses to COVID-19 mRNA Vaccines in Patients with Primary Antibody Deficiency

Immune responses to coronavirus disease 2019 (COVID-19) mRNA vaccines in primary antibody deficiencies (PADs) are largely unknown. We investigated antibody and CD4+ T-cell responses specific for SARS-CoV-2 spike protein (S) before and after vaccination and associations between vaccine response and patients' clinical and immunological characteristics in PADs. The PAD cohort consisted of common variable immune deficiency (CVID) and other PADs, not meeting the criteria for CVID diagnosis (oPADs). Anti-S IgG, IgA, and IgG subclasses 1 and 3 increased after vaccination and correlated with neutralization activity in HCs and patients with oPADs. However, 42% of CVID patients developed such responses after the 2nd dose. A similar pattern was also observed with S-specific CD4+ T-cells as determined by OX40 and 4-1BB expression. Patients with poor anti-S IgG response had significantly lower levels of baseline IgG, IgA, CD19+ B-cells, switched memory B-cells, naïve CD8+ T-cells, and a higher frequency of EM CD8+ T-cells and autoimmunity compared to patients with adequate anti-S IgG responses. Patients with oPADs can develop humoral and cellular immune responses to vaccines similar to HCs. However, a subset of CVID patients exhibit impairment in developing such responses, which can be predicted by the baseline immune profile and history of autoimmunity.

Antigen-Specific CD4+ T-Cell Activation in Primary Antibody Deficiency After BNT162b2 mRNA COVID-19 Vaccination

Previous studies on immune responses following COVID-19 vaccination in patients with common variable immunodeficiency (CVID) were inconclusive with respect to the ability of the patients to produce vaccine-specific IgG antibodies, while patients with milder forms of primary antibody deficiency such as immunoglobulin isotype deficiency or selective antibody deficiency have not been studied at all. In this study we examined antigen-specific activation of CXCR5-positive and CXCR5-negative CD4⁺ memory cells and also isotype-specific and functional antibody responses in patients with CVID as compared to other milder forms of primary antibody deficiency and healthy controls six weeks after the second dose of BNT162b2 vaccine against SARS-CoV-2. Expression of the activation markers CD25 and CD134 was examined by multi-color flow cytometry on CD4⁺ T cell subsets stimulated with SARS-CoV-2 spike peptides, while in parallel IgG and IgA antibodies and surrogate virus neutralization antibodies against SARS-CoV-2 spike protein were measured by ELISA. The results show that in CVID and patients with other milder forms of antibody deficiency normal IgG responses (titers of spike protein-specific IgG three times the detection limit or more) were associated with intact vaccine-specific activation of CXCR5-negative CD4⁺ memory T cells, despite defective activation of circulating T follicular helper cells. In contrast, CVID IgG nonresponders showed defective vaccine-specific and superantigen-induced activation of both CD4⁺T cell subsets. In conclusion, impaired TCR-mediated activation of CXCR5-negative CD4⁺ memory T cells following stimulation with vaccine antigen or superantigen identifies patients with primary antibody deficiency and impaired IgG responses after BNT162b2 vaccination.

Spectrum of Disease Manifestations in Patients with Selective Immunoglobulin E Deficiency

BACKGROUND

Selective IgE deficiency (SIgED) has been previously evaluated in selected patients from allergy units. This study investigates the effects of SIgED on the entire population in a hospital setting and sought to delineate in detail the clinical aspects of SIgED.

METHODS

A retrospective study of the data obtained from electronic medical records of 52 adult patients (56% female) with a mean age of 43 years and IgE levels of <2.0 kU/L with normal immunoglobulin (Ig) IgG, IgA, and IgM levels, seen at our hospital, without selection bias, from 2010 to 2019.

RESULTS

Recurrent upper respiratory infections were recorded in 18 (34.6%) patients, pneumonia was recorded in 16 (30.7%) patients, bronchiectasis was recorded in 16 (30.7%) patients, and asthma was recorded in 10 (19.2%) patients. Eighteen patients (34.6%) suffered autoimmune clinical manifestations either isolated (19%) or combining two or more diseases (15%), Hashimoto's thyroiditis being the most frequent (19%), which was followed by arthritis (10%) and thrombocytopenia and/or neutropenia (5.7%). Other less frequent associations were Graves' disease, primary sclerosing cholangitis, Sjögren's syndrome, and autoimmune hepatitis. Eczematous dermatitis (15.3%), chronic spontaneous urticaria (17.3%), and symptoms of enteropathy (21%) were also highly prevalent. Thirty percent of patients developed malignancies, with non-Hodgkin lymphomas (13.4%) being the most prevalent.

CONCLUSIONS

The clinical manifestations of SIgED encompass a variety of infectious, non-infectious complications, and malignancy. Since it cannot be ruled out that some type of selection bias occurred in the routine assessment of IgE serum Ievels, prospective studies are required to better characterize SIgED and to determine whether it should be added to the list of antibody deficiencies.

Effectiveness of low-dose intravenous immunoglobulin therapy in minor primary antibody deficiencies: A 2-year real-life experience

Primary antibody deficiencies (PAD) are the most prevalent group of primary immunodeficiencies (PID) in adults and immunoglobulin replacement therapy (IRT) is the mainstay therapy to improve clinical outcomes. IRT is, however, expensive and, in minor PAD, clear recommendations concerning IRT are lacking. We conducted a retrospective real-life study to assess the effectiveness of low-dose IRT in minor PAD on 143 patients fulfilling European Society for Immunodeficiencies (ESID) diagnostic criteria for immunoglobulin (Ig)G subclass deficiency (IgGSD) or unclassified antibody deficiency (UAD). All patients were treated with intravenous low-dose IRT (0.14 ± 0.06 g/kg/month). Immunoglobulin (Ig) classes and IgG subclasses were measured at baseline and after 1 year of IRT. The annual rate of total infections, upper respiratory tract infections (URTI), lower respiratory tract infections (LRTI) and hospitalizations was measured at baseline and after 1 and 2 years of IRT. After 1 year of IRT significant improvement was demonstrated in: (a) serum IgG (787.9 ± 229.3 versus 929.1 ± 206.7 mg/dl; p < 0.0001); (b) serum IgG subclasses (IgG1 = 351.4 ± 109.9 versus 464.3 ± 124.1, p < 0.0001; IgG2 = 259.1 ± 140 versus 330.6 ± 124.9, p < 0.0001; IgG3 = 50.2 ± 26.7 versus 55.6 ± 28.9 mg/dl, p < 0.002); (c) annual rate of total infections (5.75 ± 3.87 versus 2.13 ± 1.74, p < 0.0001), URTI (1.48 ± 3.15 versus 0.69 ± 1.27; p < 0.005), LRTI (3.89 ± 3.52 versus 1.29 ± 1.37; p < 0.0001) and hospitalizations (0.37 ± 0.77 versus 0.15 ± 0.5; p < 0.0002). The improvement persisted after 2 years of IRT. No significant improvement in URTI annual rate was noted in UAD and in patients with bronchiectasis. In conclusion, low-dose IRT can improve clinical outcomes in UAD and IgGSD patients, providing a potential economical advantage over the standard IRT dose.

Specific Antibody Deficiency in Adult Patients With IgG or IgG Subclass Deficiency

Purpose

Specific antibody deficiency (SAD) involves a deficient response to a polysaccharide vaccine despite having normal immunoglobulin levels. The failure of the polysaccharide response can be observed as a component of various primary antibody deficiencies. However, only a few studies have described the clinical and immunological profiles in SAD and/or other primary immunodeficiencies (PIDs) in adults.

Methods

A total of 47 patients who had a clinical history suggestive of antibody deficiency or had already been diagnosed with various antibody deficiencies were enrolled. Polysaccharide responses to 7 pneumococcal serotypes (4, 6B, 9V, 14, 18C, 19F and 23F) were measured using the World Health Organization enzyme-linked immunosorbent assay (WHO-ELISA), and postvaccination immunoglobulin G (IgG) titers were compared to clinical and laboratory parameters.

Results

Based on the American Academy of Allergy, Asthma, and Immunology (AAAAI) criteria for the WHO-ELISA, 11 (23.4%) patients were diagnosed as having SAD. Sixteen-three percent of them had combined with other types of PID, such as IgG subclass deficiency and hypogammaglobulinemia. Postvaccination IgG titers for the serotypes 4/9V/18C correlated with IgG2 (P = 0.012, P = 0.001, and P = 0.004) and for 6B/9V/14 with IgG3 (P = 0.003, P = 0.041, and P = 0.036, respectively). The IgG3 subclass levels negatively correlated with forced expiratory volume in 1 second (FEV1, %) and FEV1/forced vital capacity (P < 0.001 and P = 0.001, respectively).

Conclusion

SAD can be diagnosed in patients with normal IgG levels as well as in those deficient in IgG or the IgG3 subclass, implicating that restricted responses to Streptococcus pneumoniae polysaccharide antigens commonly exist in patients with predominantly antibody deficiency.