Primary Immunodeficiencies: Diseases of Children and Adults - A Review

Calcium, phosphorus, magnesium levels in frequent respiratory tract infections

BACKGROUND

It was well documented that calcium (Ca), phosphorus (P), and magnesium (Mg) participate in many physiological processes. We aimed to study the changing trend of serum levels of Ca, P, and Mg in frequent respiratory tract infections (FRTI) in children.

METHODS

A retrospective study was performed in our centre. A total of 213 FRTI cases and 33 controls were enrolled in our study. We analyzed the correlation between serum Ca/P/Mg levels and inflammatory indexes by using Spearman correlation analysis. Standard mean difference (SMD) was applied to test the differences of serum Ca/P/Mg levels between FRTI subgroups and controls. In terms of the findings of SMD between Ca/P/Mg status between FRTI subgroups and controls, receiver operating characteristics (ROC) curve analysis was further applied to test the association between serum Ca level and bronchitis, parainfluenza virus infection, influenza B virus infection and cytomegalovirus infection.

RESULTS

Serum Ca level was significantly associated with white blood cell (WBC), platelet (PLT) and procalcitonin (PCT) (p = 0.006; p < 10-4; p = 0.004). Serum P level was markedly associated with eryhtrocyte sedimentation rate (ESR) and PCT (p = 0.018; p < 10-4). Controls showed significantly lower serum Ca level than that among bronchitis (p = 0.001), parainfluenza virus infection (p = 0.027), influenza B virus infection (p = 0.017), cytomegalovirus infection (p = 0.029), and two pathogens infected (p = 0.020). ROC curve analysis showed that serum Ca level was significantly associated with bronchitis (p = 0.047) and influenza B virus infection (p = 0.049).

CONCLUSIONS

Serum levels of Ca and P may reflect the inflammatory status in children with FRTI. Alteration of serum Ca level may predict the risk of bronchitis and influenza B virus infection. Keeping the homeostasis of Ca, P, and Mg may be important for the prevention and treatment of FRTI.

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.

Consensus on the Key Characteristics of Immunotoxic Agents as a Basis for Hazard Identification

BACKGROUND

Key characteristics (KCs), properties of agents or exposures that confer potential hazard, have been developed for carcinogens and other toxicant classes. KCs have been used in the systematic assessment of hazards and to identify assay and data gaps that limit screening and risk assessment. Many of the mechanisms through which pharmaceuticals and occupational or environmental agents modulate immune function are well recognized. Thus KCs could be identified for immunoactive substances and applied to improve hazard assessment of immunodulatory agents.

OBJECTIVES

The goal was to generate a consensus-based synthesis of scientific evidence describing the KCs of agents known to cause immunotoxicity and potential applications, such as assays to measure the KCs.

METHODS

A committee of 18 experts with diverse specialties identified 10 KCs of immunotoxic agents, namely, 1) covalently binds to proteins to form novel antigens, 2) affects antigen processing and presentation, 3) alters immune cell signaling, 4) alters immune cell proliferation, 5) modifies cellular differentiation, 6) alters immune cell-cell communication, 7) alters effector function of specific cell types, 8) alters immune cell trafficking, 9) alters cell death processes, and 10) breaks down immune tolerance. The group considered how these KCs could influence immune processes and contribute to hypersensitivity, inappropriate enhancement, immunosuppression, or autoimmunity.

DISCUSSION

KCs can be used to improve efforts to identify agents that cause immunotoxicity via one or more mechanisms, to develop better testing and biomarker approaches to evaluate immunotoxicity, and to enable a more comprehensive and mechanistic understanding of adverse effects of exposures on the immune system. https://doi.org/10.1289/EHP10800.

Diagnostic Challenges in Patients with Inborn Errors of Immunity with Different Manifestations of Immune Dysregulation

Inborn errors of immunity (IEI), formerly known as primary immunodeficiency disorders (PIDs), are inherited disorders caused by damaging germline variants in single genes, which result in increased susceptibility to infections and in allergic, autoimmune, autoinflammatory, nonmalignant lymphoproliferative, and neoplastic conditions. Along with well-known warning signs of PID, attention should be paid to signs of immune dysregulation, which seem to be equally important to susceptibility to infection in defining IEI. The modern diagnostics of IEI offer a variety of approaches but with some problems. The aim of this review is to discuss the diagnostic challenges in IEI patients in the context of an immune dysregulation background.

Serum Allergen-Specific IgE among Pediatric Patients with Primary Immunodeficiency

Background: Allergy is a clinical condition that reflects a deviated function of the immune system. The purpose of this study was to evaluate serum allergen-specific IgE (sIgE) along with clinical manifestations of allergy in patients with diagnosed primary immunodeficiency (PID). Methods: 72 patients, aged 1−17 years, diagnosed with PID and hospitalized between July 2020 and February 2021 were included in the study. Blood samples were obtained by venipuncture. sIgE (30 allergens), blood eosinophil count, as well as total IgE and IgG were measured and assessed in relation to a detailed medical examination. Results: Serum sIgE was detected in the blood of 50% of the patients in the study group, which significantly correlated (p < 0.0001) with clinical symptoms of allergy. During the period of the study, 61.1% of the patients showed symptoms of allergy, with 77.27% of them having tested positive for sIgE. The total IgE level was elevated in 18.06% of the patients and correlated with clinical symptoms of allergy (p = 0.004). An elevated total IgE level was not observed in children receiving immunoglobulin replacement therapy. Conclusion: The study showed that serum sIgE and total IgE together might be a plausible diagnostic tool for PID patients. However, for patients receiving immunoglobulin replacement therapy, the assessment of total IgE is not useful.

Primary Antibody Deficiencies With Pulmonary Complications: A Single-Center Experience

Background

Primary immunodeficiencies are a heterogeneous group of genetic diseases caused by one or more abnormalities in the immune system. Although pulmonary complications are common in patients with primary immunodeficiency diseases, these complications contribute significantly to morbidity and mortality.

Aim

The aim of our study was to evaluate the distribution of the features of pulmonary radiological involvement and demographic findings in this patient group.

Materials and methods

The files of patients who were treated and followed up with the diagnosis of primary immunodeficiency between 2014 and 2021 were analyzed retrospectively. Demographic data, symptoms, additional diseases, and computed tomography findings of the patients were recorded.

Results

The mean age of 32 cases was 37.34±13.54 (20-69) and the age of diagnosis was 28.90±15.75 (1-62). Twenty of the cases were male and 10 were female. The most common symptom was diarrhea with 53.1% and cough with 34.4%. The most common radiological finding is bronchiectasis in 75% of cases. Twenty-one (65.6%) of the cases had recurrent pneumonia before diagnosis and no pneumonia was observed after intravenous ımmunoglobulin replacement therapy. Three of the cases (9.4%) died during the follow-up.

Conclusions

Primary immunodeficiency should be considered in patients with bronchiectasis and a history of recurrent pneumonia, and further investigations should be performed. Early diagnosis of patients with primary immunodeficiency is very important for the early detection and treatment of malignancy and the interstitial lung disease that may develop.

Assessment of COVID-19 Incidence and the Ability to Synthesise Anti-SARS-CoV-2 Antibodies of Paediatric Patients with Primary Immunodeficiency

Background: Data regarding the course of SARS-CoV-2 infection in children with primary immunodeficiency (PID) is insufficient. The purpose of the study was to evaluate the morbidity and clinical course of COVID-19 and the ability to produce anti-SARS-CoV-2 IgG antibodies in children with PID. Methods: In this retrospective study, medical records of 99 patients aged 0–18 were evaluated. The patients were divided into three groups: PID group (68.69%), control group (19.19%) and patients with ongoing or previous paediatric inflammatory multisystem syndrome (12.12%). Data such as morbidity, clinical outcome, and IgG anti-SARS-CoV-2 antibody titres were assessed. Results: A confirmed diagnosis of SARS-CoV-2 infection has been established in 26.47% of patients with PID. Among patients with PID infected with SARS-CoV-2, only three cases were hospitalised. Mortality in the PID group was 0%. Throughout an observation period of 1 year, 47.06% of patients with PID were tested positive for the anti-SARS-CoV-2 antibody. Conclusions: In the study group, in most cases the disease had a mild and self-limiting course. Remarkably, even though IgG deficiency was the most prevalent form of PID in the study group, the patients were able to respond satisfactorily to the infection in terms of anti-SARS-CoV-2 IgG.

Case Report: Borrelia-DNA Revealed the Cause of Arthritis and Dermatitis During Treatment With Rituximab

Borrelia-specific antibodies in serum did not contribute to the diagnosis of Borrelia arthritis or Borrelia-associated dermatitis in a young woman with ongoing treatment with rituximab due to multiple sclerosis. The diagnosis was confirmed by the detection of Borrelia-DNA in a skin punch biopsy. The patient history did not reveal any tick exposure. She had suffered for several months from fluctuating pain and swelling of the right knee as well as skin involvement with redness and oedema around the ankle of the same leg. Monoarthritis was confirmed by a rheumatologist. Knee puncture was performed but the synovial fluid was only sufficient for microscopic examination of crystals. Neither monosodium urate crystals nor calcium pyrophosphate crystals were found. Borrelia serology in blood revealed borderline levels of immunoglobulin (Ig)M and IgG, respectively. Treatment with doxycycline resulted in resolution of the joint and skin manifestations within a month. This case highlights that Borrelia-specific antibody levels cannot be reliably interpreted in patients who have received B-cell depleting therapy. Under these circumstances, detection of the bacterial genome in different body fluids, such as in the skin, can be a useful complement to the diagnosis of Lyme disease. In this young female, the diagnosis would certainly have been further delayed without the detection of Borrelia-DNA in the skin.