Diagnosis of Chronic Granulomatous Disease: Strengths and Challenges in the Genomic Era.

Chronic granulomatous disease (CGD) is a group of rare primary inborn errors of immunity characterised by a defect in the phagocyte respiratory burst, which leads to severe and life-threatening infective and inflammatory complications. Despite recent advances in our understanding of the genetic and molecular pathophysiology of X-linked and autosomal recessive CGD, and growth in the availability of functional and genetic testing, there remain significant barriers to early and accurate diagnosis. In the current review, we provide an up-to-date summary of CGD pathophysiology, underpinning current methods of diagnostic testing for CGD and closely related disorders. We present an overview of the benefits of early diagnosis and when to suspect and test for CGD. We discuss current and historical methods for functional testing of NADPH oxidase activity, as well as assays for measuring protein expression of NADPH oxidase subunits. Lastly, we focus on genetic and genomic methods employed to diagnose CGD, including gene-targeted panels, comprehensive genomic testing and ancillary methods. Throughout, we highlight general limitations of testing, and caveats specific to interpretation of results in the context of CGD and related disorders, and provide an outlook for newborn screening and the future.

Inflammatory Complications in Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is a rare inborn error of immunity that typically manifests with infectious complications. As the name suggest though, inflammatory complications are also common, often affecting the gastrointestinal, respiratory, urinary tracts and other tissues. These can be seen in all various types of CGD, from X-linked and autosomal recessive to X-linked carriers. The pathogenetic mechanisms underlying these complications are not well understood, but are likely multi-factorial and reflect the body's attempt to control infections. The different levels of neutrophil residual oxidase activity are thought to contribute to the large phenotypic variations. Immunosuppressive agents have traditionally been used to treat these complications, but their use is hindered by the fact that CGD patients are predisposed to infection. Novel therapeutic agents, like anti-TNFa monoclonal antibodies, anakinra, ustekinumab, and vedolizumab offer promise for the future, while hematopoietic stem cell transplantation should also be considered in these patients.

Low circulating B cells in immunocompromised individuals are linked to poorer antibody responses to vaccines and a predisposition to viral infections.

Background: B cells play an important role in protection against viral infections, not only through the production of antibodies but also through their ability to act as antigen-presenting cells and produce cytokines. Objectives: To assess whether there is a link between low circulating B-cell counts and a predisposition to viral infections in immunocompromised individuals, we performed a retrospective cohort analysis at 2 National Health Service Clinical Immunology sites in England. Methods: Eligible patients were adults who were either diagnosed with or under investigation for an immunodeficiency and had recorded circulating B-cell counts. Information on viral infections was collected by using the departmental, hospital, and laboratory electronic information systems. A generalized linear model was used to analyze the relationship between B-cell counts and relevant indices of viral infection while controlling for patient age, diagnosis group, and T-cell and natural killer cell counts. Results: A total of 376 eligible patients were identified, 134 of whom had B-cell counts that were below the laboratory-defined refence range (<0.11 ×109/L). Patients with low numbers of circulating B cells had lower pretreatment immunoglobulin levels and poorer antibody responses to vaccines (Streptococcus pneumonia, Clostridium tetani, and Haemophilus influenzae type B). An increased number of chronic or recurrent (P = .001), severe or unusual (P = .001), and PCR-confirmed viral infections (P = .04) were recorded in these patients versus in those with normal numbers of circulating B cells. Conclusion: Overall, there was a statistically significant association between low circulating B-cell counts and the incidence of clinically important viral infections in this patient cohort, even when controlling for relevant covariates. Clinicians caring for patients with immunodeficiency should be vigilant for these types of infections, particularly in patients with low peripheral B-cell counts. A prospective study will be required to confirm these findings.

COVID-19 vaccine allergy advice and guidance: The experience of a UK tertiary referral centre.

Objective: The objective was to review COVID-19 vaccine allergy advice and guidance requests received and assess the impact of advice outcome on vaccination outcome. Design: A retrospective analysis of requests for advice and guidance regarding COVID-19 vaccine allergy was completed using an electronic referral system from February 2021 to January 2022. Participants: A total of 1265 independent patient requests for advice were received from primary care. Full vaccination information was available on 1210 patients who were included in the analysis. Main outcome measures: We evaluated the specific outcome of request for advice (written advice versus allergy consultation), rate of vaccination, vaccination combinations, and tolerance of vaccination. Results: Of the 1210 patients included, 959 (79%) were female. Eight hundred and ninety-six (74%) requests were managed with written advice only and of these 675 (75%) patients went on to be vaccinated. Overall, 891 (74%) of the population were vaccinated with 2 or more doses.Two hundred and nineteen patient consultations were undertaken with 109 (50%) prior to the first vaccination. Forty-nine (45%) consultations prior to vaccination were undertaken due to a label of anaphylaxis to vaccination in the past. Vaccination was recommended for all patients, and 78 (72%) of these received a first dose. Eight of these patients (10%) had symptoms within 1 h of vaccine administration.One hundred and ten (50%) consultations were undertaken for adverse reactions post COVID-19 vaccination, with 84 (76%) concerning immediate symptoms. Thirty patients (27%) who had a consultation had had adrenaline administered post vaccination. One patient had biopsy confirmed Stevens Johnson Syndrome and was referred to Dermatology. All others due for further doses (107 patients) were recommended to have subsequent doses with 49 (45%) offered the same vaccine. Eighty-nine patients had a vaccine administered post adverse reaction and 79 (88%) tolerated the dose.Skin testing and challenge to polyethylene glycol were negative in the 8 patients tested. Conclusions: Over 1000 requests for advice and guidance were received during the review period, managed mainly with written advice. The overwhelming majority of requests for advice and consultations were for females, with equal distribution both pre- and post-COVID-19 vaccine administration. Vaccination was recommended in all but 1 patient (with biopsy confirmed Stevens Johnson Syndrome). Polyethylene glycol allergy was not confirmed in any patient, nor did any patient have confirmed anaphylaxis when the vaccine was administered under our supervision, suggesting that type 1 mediated hypersensitivity is uncommon even in this "high risk" population.

Peripheral B Cell Deficiency and Predisposition to Viral Infections: The Paradigm of Immune Deficiencies.

In the era of COVID-19, understanding how our immune system responds to viral infections is more pertinent than ever. Immunodeficiencies with very low or absent B cells offer a valuable model to study the role of humoral immunity against these types of infection. This review looks at the available evidence on viral infections in patients with B cell alymphocytosis, in particular those with X-linked agammaglobulinemia (XLA), Good's syndrome, post monoclonal-antibody therapy and certain patients with Common Variable Immune Deficiency (CVID). Viral infections are not as infrequent as previously thought in these conditions and individuals with very low circulating B cells seem to be predisposed to an adverse outcome. Particularly in the case of SARS-CoV2 infection, mounting evidence suggests that peripheral B cell alymphocytosis is linked to a poor prognosis.

CNS demyelination associated with immune dysregulation and a novel CTLA-4 variant.

BACKGROUND: The cytotoxic T-lymphocyte antigen-4 (CTLA-4) pathway acts as a negative immune regulator of T-cell activation and promotes self-tolerance. CASE: We report the first case of biopsy-proven central nervous system inflammatory demyelination in the context of primary immunodeficiency and a novel CTLA-4 variant. CONCLUSION: This case has significant implications for the development of novel treatments for autoimmune conditions including multiple sclerosis and further emphasises the need for caution with clinical use of CTLA-4 immune checkpoint inhibitors in those with a history of inflammatory demyelination.

How to investigate a suspected immune deficiency in adults.

Patients with immune deficiencies can present with variable clinical phenotypes. This often translates into a significant delay in their diagnosis, and resultant patient morbidity. This review summarises the most common types of immunodeficiency disorders, primary and secondary, along with their key features. It provides a structured approach for the clinician on when to suspect an immunodeficiency, the initial investigations pathway and when a specialist referral should be considered.

Stat3 promotes IL-10 expression in lupus T cells through trans-activation and chromatin remodeling.

The immune-regulatory cytokine IL-10 plays a central role during innate and adaptive immune responses. IL-10 is elevated in the serum and tissues of patients with systemic lupus erythematosus (SLE), an autoimmune disorder characterized by autoantibody production, immune-complex formation, and altered cytokine expression. Because of its B cell-promoting effects, IL-10 may contribute to autoantibody production and tissue damage in SLE. We aimed to determine molecular events governing T cell-derived IL-10 expression in health and disease. We link reduced DNA methylation of the IL10 gene with increased recruitment of Stat family transcription factors. Stat3 and Stat5 recruitment to the IL10 promoter and an intronic enhancer regulate gene expression. Both Stat3 and Stat5 mediate trans-activation and epigenetic remodeling of IL10 through their interaction with the histone acetyltransferase p300. In T cells from SLE patients, activation of Stat3 is increased, resulting in enhanced recruitment to regulatory regions and competitive replacement of Stat5, subsequently promoting IL-10 expression. A complete understanding of the molecular events governing cytokine expression will provide new treatment options in autoimmune disorders, including SLE. The observation that altered activation of Stat3 influences IL-10 expression in T cells from SLE patients offers molecular targets in the search for novel target-directed treatment options.

A T cell gene expression panel for the diagnosis and monitoring of disease activity in patients with systemic lupus erythematosus.

Systemic Lupus Erythematosus (SLE) remains a challenging disease to diagnose and follow, as no reliable biomarkers are known to date. We designed a gene expression panel with 40 genes known to play a role in SLE pathogenesis. We found that the combined expression of these genes in SLE T cells can accurately differentiate SLE from healthy individuals and patients with other autoimmune diseases. The accuracy of the test increased further (83%) when only three out of the initial genes (OAS2, CD70 and IL10) were used. A T cell score, calculated from the combined expression levels of these genes, correlated positively with various SLE activity markers in a cross-sectional cohort and in a few patients that were followed prospectively. These data showcase the usefulness of measuring mRNA levels of key molecules in diagnosing and following patients with SLE.

Spleen tyrosine kinase (Syk) regulates systemic lupus erythematosus (SLE) T cell signaling.

Engagement of the CD3/T cell receptor complex in systemic lupus erythematosus (SLE) T cells involves Syk rather than the zeta-associated protein. Because Syk is being considered as a therapeutic target we asked whether Syk is central to the multiple aberrantly modulated molecules in SLE T cells. Using a gene expression array, we demonstrate that forced expression of Syk in normal T cells reproduces most of the aberrantly expressed molecules whereas silencing of Syk in SLE T cells normalizes the expression of most abnormally expressed molecules. Protein along with gene expression modulation for select molecules was confirmed. Specifically, levels of cytokine IL-21, cell surface receptor CD44, and intracellular molecules PP2A and OAS2 increased following Syk overexpression in normal T cells and decreased after Syk silencing in SLE T cells. Our results demonstrate that levels of Syk affect the expression of a number of enzymes, cytokines and receptors that play a key role in the development of disease pathogenesis in SLE and provide support for therapeutic targeting in SLE patients.

Splicing factor SF2/ASF rescues IL-2 production in T cells from systemic lupus erythematosus patients by activating IL-2 transcription.

T cells from patients with systemic lupus erythematosus (SLE) produce insufficient amounts of the vital cytokine IL-2. We previously showed that SLE T cells express decreased levels of the T-cell receptor-CD3ζ chain and forced expression of CD3ζ into SLE T cells restores IL-2 production. We recently showed that the serine arginine protein splicing factor 2/alternative splicing factor (SF2/ASF) enhances the expression of CD3ζ chain by limiting the production of an unstable splice variant. Here we demonstrate that SF2/ASF levels are decreased in patients with SLE and more so in those with active disease. More importantly, we reveal a function of SF2/ASF, independent of T-cell receptor/CD3 signaling, whereby it is recruited to the IL-2 promoter, increases transcriptional activity, and enhances IL-2 production in SLE T cells. Our results demonstrate that SF2/ASF regulates IL-2 production and that decreased SF2/ASF expression in SLE T cells contributes to deficient IL-2 production.

cAMP-responsive element modulator α (CREMα) contributes to decreased Notch-1 expression in T cells from patients with active systemic lupus erythematosus (SLE).

Notch signaling constitutes an evolutionarily conserved pathway that transduces signals between neighboring cells and determines major decisions in cell proliferation, survival, and differentiation. Notch signaling has been shown to play a pivotal role during T cell lineage determination. T lymphocytes from patients with systemic lupus erythematosus (SLE) display a severely altered phenotype with several molecular and functional aberrations, including defective capacities to up-regulate Notch-1 receptor expression upon T cell receptor activation. Here, we demonstrate that basal Notch-1 expression is decreased in T cells from active SLE patients at the mRNA and protein levels in various T cell subpopulations. Notch-1 transcript numbers inversely correlate with disease activity in SLE patients. We provide evidence that both enhanced histone H3 methylation and CpG DNA methylation of the human Notch-1 promoter contribute to decreased Notch-1 expression in SLE T cells. Previous data from our group identified cAMP-responsive element modulator α (CREMα), which is up-regulated in SLE T cells, as a key regulator of epigenetic patterns and gene transcription, e.g. that of IL2 and IL17 genes. In this study, we observed increased CREMα binding to the Notch-1 promoter, which eventually resulted in significantly reduced Notch-1 promoter activity and gene transcription. Notably, decreased Notch-1 levels were associated with elevated IL-17A levels. Our data suggest a role for Notch-1 in SLE immunopathogenesis, and for the first time, we present molecular mechanisms that mediate dysregulated Notch-1 expression in SLE T cells.

Immunodeficiency and autoimmunity: lessons from systemic lupus erythematosus.

Recent evidence suggests that systemic autoimmunity and immunodeficiency are not separate entities, but rather are interconnected processes. Immunodeficiency results from distinct defects of the immune response and primarily presents as infections but also frequently with autoimmune features. Systemic autoimmunity is the combined effect of multiple genetic variations and infectious and immunoregulatory factors that result in dominant autoimmune manifestations, in addition to frequent and opportunistic infections. The overlap in disease manifestations and symptoms suggests that immunodeficiency should be considered in the presence of autoimmunity, and vice versa. In this review, we present the shared or similar aspects of immunodeficiency and autoimmunity using systemic lupus erythematosus as a paradigm and discuss the implications for clinical care.

Keap1 mutations and Nrf2 pathway activation in epithelial ovarian cancer.

Resistance to platinum-based chemotherapy develops in the majority of patients with epithelial ovarian cancer (EOC). Platinum compounds form electrophilic intermediates that mediate DNA cross-linking and induce double-strand DNA breaks. Because the cellular response to electrophilic xenobiotics is partly mediated by Keap1-Nrf2 pathway, we evaluated the presence of Kelch-like ECH-associated protein 1 (Keap1) mutations and NF-E2-related factor 2 (Nrf2) pathway activation in EOC and correlated these with platinum resistance and clinical outcome. Nrf2 immunohistochemistry revealed nuclear localization (a surrogate of pathway activation) in over half of EOC patient specimens examined, with more common occurrence in the clear cell EOC subtype. Quantitative real-time PCR revealed that Nrf2 target genes were upregulated in tumors with nuclear positivity for Nrf2. Microarray analysis also showed upregulation of Nrf2 target genes in clear cell EOCs compared with other EOC subtypes. In addition, Keap1 sequence analysis revealed genetic mutations in 29% of clear cell samples and 8% of nonclear cell tumors. RNAi-mediated knockdown of Keap1 was associated with Nrf2 pathway activation and resistance to carboplatin in vitro. Importantly, patients with evidence of Nrf2 pathway activation had fewer complete clinical responses to platinum-based therapy, were enriched for platinum resistance, and had shorter median overall survival compared with those who did not show evidence of Nrf2 pathway activation. Our findings identify Keap1 mutations in EOC and they suggest a previously unrecognized role for the Keap1-Nrf2 pathway in mediating chemotherapeutic responses in this disease.