Primary Immunodeficiency Patients Research Articles

Autoimmune manifestations following COVID-19 infection in two individuals with primary immunodeficiency

Background: Due to widespread vaccination efforts worldwide, the mortality rates linked to COVID-19 have been decreasing. Nevertheless, there persists a notable level of morbidity, marked by increased occurrences of post-COVID-19 conditions. This includes the development of new autoimmune and inflammatory diseases in individuals who have recovered from COVID-19. A more severe progression of COVID-19 has been correlated with an increased probability of newly diagnosed autoimmune disease, and among individuals with preexisting autoimmune conditions, COVID-19 increased the risk of developing another autoimmune disease by 23%. Methods: Our patients’ medical records were analyzed retrospectively, including their medical history. Results: We present two cases of primary immunodeficiency patients. One of them experienced the onset of new autoimmune symptoms, while the other had a worsening of her autoimmune condition following COVID-19 infection. Conclusion: Recognizing the potential connection between COVID-19 and autoimmune conditions is crucial for identifying symptoms promptly in primary immunodeficiency patients and ensuring timely treatment. Further research is required to comprehensively grasp the relationship between COVID-19 and the development of autoimmunity in this particular patient group. Statement of Novelty: In this paper, we present a novel exploration into the emergence of autoimmune manifestations in primary immunodeficiency patients subsequent to COVID-19 infection, through an analysis of two distinct case reports.

Primary immunodeficiency as a cause of immune-mediated kidney diseases.

Primary immunodeficiency (PID) is no longer defined by infections alone, and autoimmunity is an accompanying manifestation of PID. Recurrent infections may trigger autoimmunity through molecular mimicry, bystander activation, or superantigens. The diagnosis of PID is still challenging, but genetic analysis reveals the underlying link between PID and autoimmunity. Mutations in relevant genes affecting central and peripheral immune tolerance, regulatory T-cell function, expansion of autoreactive lymphocytes, antigen clearance, hyperactivation of type I interferon, and NF-κB pathways have all been implicated in triggering autoimmunity in PID. Autoimmunity in PID leads to chronic inflammation, tissue damage, and organ failure and increases the mortality of patients with PID. The kidneys are inextricably linked with the immune system, and kidney diseases can be mediated by both infection and autoimmunity/inflammation in PID patients. The manifestations of kidney involvement in PID patients are very heterogeneous and include lupus nephritis, C3 glomerulopathy, kidney thrombotic microangiopathy, vasculitis, and interstitial nephritis.Patients with PID-caused kidney diseases have defined immune function defects and may benefit from pathway-based biologics, stem cell transplantation, or gene therapy. Early diagnosis and appropriate treatment of PID are crucial for reducing the mortality rate and improving organ function and quality of life.

Clinical immunology in Poland: achievements and challenges – status as for 2024

The dynamic development of clinical immunology in Europe began in mid 1980s, and was continued in Poland shortly thereafter. In 1993 the first national consultant in the field of clinical immunology was appointed in Poland. A milestone was the establishment of the Polish Working Group for Primary Immunodeficiencies (PGR for PID) in 2005. Since then, a network of numerous paediatric and internal medicine centres has been created within the Group, facing and resolving new challenges in the field. The study presents the organization of care for patients with primary and secondary immunodeficiencies in Poland, analyzes the staffing situation and patients' access to diagnostics and treatment between late 1980’s and 2024. The summary presents the achievements resulting in improved diagnostic efficiency, shortening the delay in the diagnosis of Inborn Errors of Immunity (IEI)/primary immunodeficiencies (PID), and better access of patients to therapy within drug programs, largely carried out at home. The causes hindering the development of specialization are also analyzed. The most important among them are the lack of systemic support on the part of medical care organizers and the lack of motivation of young doctors to pursue specialization. The main goal is to improve diagnostic and therapeutic procedures for PID patients, including newborn screening, highly specialized, genetic test regardless where they are implemented. It can be only achieved with their better financing. An essential problem is the lack of an epidemiological or clinical IEI registry.

CARD11 regulates the thymic Treg development in an NF-κB-independent manner.

CARD11 is a lymphoid lineage-specific scaffold protein regulating the NF-κB activation downstream of the antigen receptor signal pathway. Defective CARD11 function results in abnormal development and differentiation of lymphocytes, especially thymic regulatory T cells (Treg). In this study, we used patients' samples together with transgenic mouse models carrying pathogenic CARD11 mutations from patients to explore their effects on Treg development. Immunoblotting and a GFP receptor assay were used to evaluate the activation effect of CARD11 mutants on NF-κB signaling. Then the suppressive function of Tregs carrying distinct CARD11 mutations was measured by in vitro suppression assay. Finally, we applied the retroviral transduced bone marrow chimeras to rescue the Treg development in an NF-κB independent manner. We found CARD11 mutations causing hyper-activated NF-κB signals also gave rise to compromised Treg development in the thymus, similar to the phenotype in Card11 deficient mice. This observation challenges the previous view that CARD11 regulates Treg lineage dependent on the NF-kB activation. Mechanistic investigations reveal that the noncanonical function CARD11, which negatively regulates the AKT/ FOXO1 signal pathway, is responsible for regulating Treg generation. Moreover, primary immunodeficiency patients carrying CARD11 mutation, which autonomously activates NF-κB, also represented the reduced Treg population in their peripheral blood. Our results propose a new regulatory function of CARD11 and illuminate an NF-κB independent pathway for thymic Treg lineage commitment.

Gene Signature of Regulatory T Cells Isolated from Children with Selective IgA Deficiency and Common Variable Immunodeficiency.

Selective IgA deficiency (SIgAD) is the most common form and common variable immunodeficiency (CVID) is the most symptomatic form of predominant antibody deficiency. Despite differences in the clinical picture, a similar genetic background is suggested. A common feature of both disorders is the occurrence of autoimmune conditions. Regulatory T cells (Tregs) are the major immune cell type that maintains autoimmune tolerance. As the different types of abnormalities of Treg cells have been associated with autoimmune disorders in primary immunodeficiency (PID) patients, in our study we aimed to analyze the gene expression profiles of Treg cells in CVID and SIgAD patients compared to age-matched healthy controls. The transcriptome-wide gene profiling was performed by microarray technology. As a result, we analyzed and visualized gene expression patterns of isolated population of Treg cells. We showed the differences at the gene level between patients with and without autoimmunizations. Our findings suggest that the gene signatures of Treg cells isolated from SIgAD and CVID patients differ from age-matched healthy controls and from each other, presenting transcriptional profiles enriched in innate immune or Th response, respectively. The occurrence of autoimmunity in both types of PID is associated with down-regulation of class I IFNs signaling pathways. In summary, our findings improve our understanding of Treg dysfunctions in patients with common PIDs and associated autoimmunity.

Stability of gut microbiome after COVID-19 vaccination in healthy and immuno-compromised individuals.

Bidirectional interactions between the immune system and the gut microbiota are key contributors to various physiological functions. Immune-associated diseases such as cancer and autoimmunity, and efficacy of immunomodulatory therapies, have been linked to microbiome variation. Although COVID-19 infection has been shown to cause microbial dysbiosis, it remains understudied whether the inflammatory response associated with vaccination also impacts the microbiota. Here, we investigate the temporal impact of COVID-19 vaccination on the gut microbiome in healthy and immuno-compromised individuals; the latter included patients with primary immunodeficiency and cancer patients on immunomodulating therapies. We find that the gut microbiome remained remarkably stable post-vaccination irrespective of diverse immune status, vaccine response, and microbial composition spanned by the cohort. The stability is evident at all evaluated levels including diversity, phylum, species, and functional capacity. Our results indicate the resilience of the gut microbiome to host immune changes triggered by COVID-19 vaccination and suggest minimal, if any, impact on microbiome-mediated processes. These findings encourage vaccine acceptance, particularly when contrasted with the significant microbiome shifts observed during COVID-19 infection.

Facilitated Subcutaneous Immunoglobulin Treatment Increases the Quality of Life and Decreases the Number of Infections and Hospitalizations in Children with Primary Immunodeficiencies

Introduction: Immunoglobulin replacement therapy is an effective lifelong treatment modality used in patients with primary immunodeficiency to prevent and/or reduce the incidence of serious infections. Facilitated subcutaneous immunoglobulin (fSCIG) was developed to combine the advantages of intravenous immunoglobulin (IVIG) and subcutaneous immunoglobulin (SCIG) and is the latest method of immunoglobulin G (IgG) administration. In this study, switching to fSCIG administration in primary immunodeficiency patients receiving regular IVIG or SCIG therapy was evaluated, and serum IgG trough levels, frequency of infections, frequency and duration of hospitalizations, duration of absence from school/work, and quality of life were determined. Methods: In this study, fifteen patients with primary immunodeficiency who were previously receiving IVIG or SCIG treatment, followed by fSCIG, were evaluated retrospectively. Age, diagnosis, current complications, mean IgG value, frequency of infection, frequency of hospitalization, and duration of absenteeism from school and work were recorded during and before fSCIG treatment. At the beginning of fSCIG treatment, at 6th and 12th months, “The Quality of Life Scale” was also evaluated in patients and parents. Results: The most common indications for initiation of fSCIG treatment were the difficulty of access to the hospital and the long transfusion periods. No systemic adverse reactions were reported except for redness, swelling, and mild pain on the injection site. The median IgG values for the last 1 year were 529.6 mg/dL for IVIG (n = 9), 876.2 mg/dL for SCIG (n = 6) and 856.7 mg/dL for fSCIG (n = 15, all patients) treatment. The frequency of infections and the number of hospitalizations decreased significantly in the fSCIG group compared to both previous treatment modalities. There was a significant increase in the quality of life score of the patients and their families when compared with previous treatment modalities. Conclusion: fSCIG is an effective treatment method and is well tolerated in patients with immunodeficiency. It provides stable immunoglobulin levels and excellent protection against infections and offers the patients the possibility of home-based therapy.

Chronic or recurrent Campylobacter enteritis in primary immunodeficiency: a UK national case-series and review of the literature.

Chronic or recurrent Campylobacter enteritis in primary immunodeficiency: a UK national case-series and review of the literature.

Transition practice for primary immunodeficiency diseases in Southeast Asia: a regional survey.

With increased diagnostic capabilities and treatment modalities in the field of primary immunodeficiencies (PID), many pediatric patients survive beyond childhood and experience a change of care to the adult-oriented healthcare system. Unfortunately, the transition pathways for PID are less clearly defined, resulting in deterioration of quality of care in adulthood. Hence, this is the first regional study to address PID clinicians' opinions on practices and challenges of transition care in 7 Southeast Asia (SEA) countries. We adopted a cross-sectional study design through an online survey platform to enquire opinions of transition practices from expert representatives in 7 SEA countries. Regionally, 3 out 7 countries reported having no practice of transition care. Among cited challenges were reluctant adaptation by patients and caregivers to unfamiliarized adult healthcare systems, inadequate ratio of adult immunologists to patients and lack of facilities for transfer. Our study provides evidence to advocate policy makers on the importance of standardized integration of transition practice towards betterment of transiting PID patients into adulthood.

Assessment of Enterovirus Excretion and Identification of VDPVs in Patients with Primary Immunodeficiency in India: Outcome of ICMR-WHO Collaborative Study Phase-I.

The emergence of vaccine-derived polioviruses (VDPVs) in patients with Primary Immunodeficiency (PID) is a threat to the polio-eradication program. In a first of its kind pilot study for successful screening and identification of VDPV excretion among patients with PID in India, enteroviruses were assessed in stool specimens of 154 PID patients across India in a period of two years. A total of 21.42% of patients were tested positive for enteroviruses, 2.59% tested positive for polioviruses (PV), whereas 18.83% of patients were positive for non-polio enteroviruses (NPEV). A male child of 3 years and 6 months of age diagnosed with Hyper IgM syndrome was detected positive for type1 VDPV (iVDPV1) with 1.6% nucleotide divergence from the parent Sabin strain. E21 (19.4%), E14 (9%), E11 (9%), E16 (7.5%), and CVA2 (7.5%) were the five most frequently observed NPEV types in PID patients. Patients with combined immunodeficiency were at a higher risk for enterovirus infection as compared to antibody deficiency. The high susceptibility of PID patients to enterovirus infection emphasizes the need for enhanced surveillance of these patients until the use of OPV is stopped. The expansion of PID surveillance and integration with a national program will facilitate early detection and follow-up of iVDPV excretion to mitigate the risk for iVDPV spread.

Asymptomatic immunodeficiency-associated vaccine-derived poliovirus infections in two UK children

Increasing detections of vaccine-derived poliovirus (VDPV) globally, including in countries previously declared polio free, is a public health emergency of international concern. Individuals with primary immunodeficiency (PID) can excrete polioviruses for prolonged periods, which could act as a source of cryptic transmission of viruses with potential to cause neurological disease. Here, we report on the detection of immunodeficiency-associated VDPVs (iVDPV) from two asymptomatic male PID children in the UK in 2019. The first child cleared poliovirus with increased doses of intravenous immunoglobulin, the second child following haematopoetic stem cell transplantation. We perform genetic and phenotypic characterisation of the infecting strains, demonstrating intra-host evolution and a neurovirulent phenotype in transgenic mice. Our findings highlight a pressing need to strengthen polio surveillance. Systematic collection of stool from asymptomatic PID patients who are at high risk for poliovirus excretion could improve the ability to detect and contain iVDPVs.

Assessment of autoantibodies in paediatric population with primary immunodeficiencies: a pilot study

BackgroundThe correlation between primary immunodeficiencies (PIDs) and autoimmunity shows ethnic and geographical diversity. The aim of our study was to accumulate more data in paediatric PID population.Methods58 children aged 1–17 and with PID (study group) and 14 age-matched immunocompetent individuals (control group) were included in the study. Serum levels of 17 different specific IgG antibodies against autoantigens were measured by means of a quantitative enzyme immunoassay. Immunoglobulin levels were analysed in relation to a detailed medical examination.ResultsAutoantibodies against one or more antigens were detected in the sera of 24.14% (n = 14) subjects in the study group. The most frequent were anti-thyroid peroxidase (anti-TPO) antibodies (n = 8; 13.8%). Anti-TPO antibody levels were elevated more often in PID patients with a positive family history of autoimmune diseases (p = 0.04). The screening for anti-deamidated gliadin peptide (DGP) and anti-tissue transglutaminase (tTG) antibodies in our series allowed identifying two previously undiagnosed cases of coeliac disease in PID patients. There was no statistically significant difference between the study and the control group in terms of the autoantibodies prevalence.ConclusionsThis study provides data on the prevalence of autoantibodies in paediatric population diagnosed with PID. Selected autoantibodies (i.e. anti-tTG, anti-DGP) might be useful for the screening of PID to avoid the delay of diagnosis of an autoimmune disease.

Development of a primary care screening algorithm for the early detection of patients at risk of primary antibody deficiency

BackgroundPrimary antibody deficiencies (PAD) are characterized by a heterogeneous clinical presentation and low prevalence, contributing to a median diagnostic delay of 3–10 years. This increases the risk of morbidity and mortality from undiagnosed PAD, which may be prevented with adequate therapy. To reduce the diagnostic delay of PAD, we developed a screening algorithm using primary care electronic health record (EHR) data to identify patients at risk of PAD. This screening algorithm can be used as an aid to notify general practitioners when further laboratory evaluation of immunoglobulins should be considered, thereby facilitating a timely diagnosis of PAD.MethodsCandidate components for the algorithm were based on a broad range of presenting signs and symptoms of PAD that are available in primary care EHRs. The decision on inclusion and weight of the components in the algorithm was based on the prevalence of these components among PAD patients and control groups, as well as clinical rationale.ResultsWe analyzed the primary care EHRs of 30 PAD patients, 26 primary care immunodeficiency patients and 58,223 control patients. The median diagnostic delay of PAD patients was 9.5 years. Several candidate components showed a clear difference in prevalence between PAD patients and controls, most notably the mean number of antibiotic prescriptions in the 4 years prior to diagnosis (5.14 vs. 0.48). The final algorithm included antibiotic prescriptions, diagnostic codes for respiratory tract and other infections, gastro-intestinal complaints, auto-immune symptoms, malignancies and lymphoproliferative symptoms, as well as laboratory values and visits to the general practitioner.ConclusionsIn this study, we developed a screening algorithm based on a broad range of presenting signs and symptoms of PAD, which is suitable to implement in primary care. It has the potential to considerably reduce diagnostic delay in PAD, and will be validated in a prospective study.Trial registration The consecutive prospective study is registered at clinicaltrials.gov under NCT05310604

Clinical Features and Genetic Analysis of Taiwanese Primary Immunodeficiency Patients with Prolonged Diarrhea and Monogenetic Inflammatory Bowel Disease.

Diarrhea lasting longer than 14days which fails to respond to conventional management is defined as severe and protracted diarrhea and might overlap with inflammatory bowel disease (IBD). The prevalence, associated pathogens, and prognosis of severe and protracted diarrhea without IBD (SD) and with monogenetic IBD (mono-IBD) in primary immunodeficiency patients (PID) were investigated in Taiwan. A total of 301 patients were enrolled between 2003 and 2022, with predominantly pediatric-onset PID. Of these, 24 PID patients developed the SD phenotype before prophylactic treatment, including Btk (six), IL2RG (four), WASP, CD40L, gp91 (three each), gp47, RAG1 (one each), CVID (two), and SCID (one) without identified mutations. The most detectable pathogens were pseudomonas and salmonella (six each), and all patients improved after approximately 2weeks of antibiotic and/or IVIG treatments. Six (25.0%) mortalities without HSCT implementation were due to respiratory failure from interstitial pneumonia (3 SCID and 1 CGD), intracranial hemorrhage (WAS), and lymphoma (HIGM). In the mono-IBD group, seventeen patients with mutant TTC7A (2), FOXP3 (2), NEMO (2), XIAP (2), LRBA (1), TTC37 (3), IL10RA (1), STAT1 (1), ZAP70 (1), PIK3CD (1), and PIK3R1 (1) genes failed to respond to aggressive treatments. Nine mono-IBD patients with TTC7A (2), FOXP3 (2), NEMO (2), XIAP (2), and LRBA (1) mutations were fatal in the absence of HSCT. The mono-IBD group had a significantly earlier age of diarrhea onset (1.7 vs 33.3months, p = 0.0056), a longer TPN duration (34.2 vs 7.0months, p < 0.0001), a shorter follow-up period (41.6 vs 132.6months, p = 0.007), and a higher mortality rate (58.9 vs 25.0%, p = 0.012) compared with the SD group. When compared to those with the SD phenotype, the mono-IBD patients had significant early-onset and poor responses to empiric antibiotics, IVIG, and steroids. Anti-inflammatory biologics and suitable HSCT still have the potential to control or even cure the mono-IBD phenotype.

AIOLOS haploinsufficiency is associated with immunodeficiency, autoimmunity, and allergy

AIOLOS is a transcription factor of the IKAROS family, that is highly expressed in the lymphoid lineage and plays an important role in lymphocyte differentiation and development. Recently, two heterozygous AIOLOS germline mutations (G159R and N160S) were reported in primary immunodeficiency patients. Both variants associated distinctive and unique T and B cell differentiation defects, hematologic malignancies, and infectious disease susceptibility patterns through different dominant negative (DN) mechanisms. Here we report seven individuals from three unrelated families carrying AIOLOS variants Q402* (nonsense, 1 family) and E82K (missense, 2 families), leading to AIOLOS haploinsufficiency through different mechanisms of action. Clinically, patients with AIOLOS haploinsufficiency showed hypogammaglobulinemia, recurrent respiratory tract infections, and immune dysregulation manifested by autoimmunity and allergy, with incomplete clinical penetrance. Mechanistically, while the nonsense mutant Q402* is devoid of its C-terminal zinc-finger (ZF) dimerization domain (ZF5-6), it is still able to homodimerize with wildtype (WT) AIOLOS although unable to heterodimerize with WT IKAROS or HELIOS. We introduce new insights into AIOLOS biology as we found that AIOLOS ZF1, a part of AIOLOS DNA binding domain (ZF1-4), was associated with noncanonical dimerization and negative regulation of DNA binding. Further studies revealed that the mutant Q402* displayed abnormalities of DNA binding, pericentromeric targeting, post-transcriptional modification, and transcriptome regulation by haploinsufficiency. In contrast, mutant E82K showed overall normal AIOLOS functions; however, by affecting a newly defined AIOLOS protein stability domain, it also led to AIOLOS haploinsufficiency. Unlike the previously reported AIOLOS mutations, heterozygous variants Q402* and E82K do not have a DN effect over other IKAROS family proteins. Our data extend the spectrum of pathogenic variants of AIOLOS-associated diseases and provide a novel mechanism of homodimerization and protein stability that, when disrupted, could affect human health.

Identifying patients with primary immunodeficiency using statistical modelling of unique genetic signatures from transcriptomic data

Primary immunodeficiencies (PID) are a group of rare disorders, most typically characterised by frequent and/or severe infections that are often caused by a genetic mutation. Early diagnosis is critical for patients as diagnostic delay is associated with increased morbidity and mortality. This study evaluated a novel diagnostic test for primary antibody deficiency, using whole blood from patients diagnosed with predominantly antibody deficiency (n = 15) as well as age-matched healthy donors (n = 18). PID patients comprised both adults (22–65 years, n = 18) and children (ages 6–18, n = 15), with 40% male (n = 13), 59% female (n = 19), and 1% gender not specified (n = 1). Inclusion criteria for patients were as follows: a) had an antibody deficiency b) an underlying in-born error of immunity and c) were under immunoglobulin replacement therapy.We used RNA-seq to characterise the transcriptome of each participant. We identified >2000 genes which were significantly differentially expressed between PID patients and healthy controls, with a p-value < 0.05. We used these signatures to train and test models to differentiate patients with PID from the healthy population. Additionally, in our blinded analysis, we identified the most variable genes in this cohort that were distinct from the differentially expressed genes and also evaluated their predictive utility. Using groups of differentially expressed genes and most variable genes in varying quantities, we generated multiple predictive models with an AUC > 0.9 for detection of primary immunodeficiency using leave-out-one cross validation.Our predictive algorithm using a transcriptomic signature, which we refer to as PrimDx, can help to identify patients with PID. This has the potential to accelerate time to diagnosis and initiation of treatment, thereby leading to better patient health outcomes. Future studies will verify this predictive algorithm in larger patient samples, and expand the application of this diagnostic approach in patients with other immunodeficiency conditions. [Display omitted]

Mild COVID-19 clinical course among paediatric patients with primary immunodeficiency

BackgroundThe clinical course of coronavirus disease-2019 (COVID-19) varies from those who are asymptomatic, experience mild symptoms such as fever, cough, and dyspnea, to more severe outcomes including acute respiratory distress, pneumonia, renal failure, and death. Early reports suggested severe outcomes in patients with primary immunodeficiency (PID), particularly those with type 1 interferon signalling defects. This prompted a rigid approach to social distancing to protect this patient population, particularly children. To date, real-world data describing the course and outcome of COVID-19 in paediatric PID patients remains scarce. MethodsIn this retrospective case series, we describe the clinical course of 36 paediatric patients with underlying primary immunodeficiency (PID) followed by SickKids Hospital (Toronto, Canada) who were symptomatic and tested positive for SARS-CoV-2 infection between October 2020 to November 2022. ResultsOur cohort consisted of patients with combined immunodeficiency (66.7%), antibody deficiency (22.2%), neutrophil dysfunction (8.3%), and immune dysregulation (2.8%). The median age was 7.5 years (range: 8 months – 17 years), with 21 male and 15 female patients. Three (8.3%) patients were post-hematopoietic stem cell transplant (HSCT) and 12 (33%) patients were on immunoglobulin replacement. Nine (25%) patients had underlying lung problems including bronchiectasis (1), interstitial lung disease on home oxygen therapy (1), and underlying asthma (7). Most patients had mild clinical course and were managed at home. The most common symptoms were fever (80%), cough (75%) and other upper respiratory tract symptoms (72%). Nineteen (52.7%) patients experienced other symptoms which included headache, lethargy, or gastrointestinal upset. At the time of the infection, 13 patients (36.1%) had received 2 doses of a SARS-CoV-2 vaccine, 5 patients (13.9%) had received 1 dose, and 18 (50%) were not vaccinated. None of the patients received antiviral or monoclonal antibody as prophylaxis or treatment. Only 1 patient required hospital admission out of precaution given the close proximity to HSCT. All patients recovered without complications. ConclusionThe paediatric patients with PID followed by our centre experienced mild to moderate COVID-19 symptoms and recovered fully without complications. These findings support the return of much needed social interactions among children, which were impacted severely during the COVID-19 pandemic.

T cell exocytosis testing provides superior sensitivity for the diagnosis of familial HLH

The rapid diagnosis of primary immunodeficiencies (PID) affecting cytotoxic lymphocyte granule exocytosis is commonly performed by evaluating NK cell surface CD107a expression after K562 challenge. NK cell exocytosis can also be induced by stimulating NK cells with P815 and anti-CD16 antibody. We have previously described how these NK tests can be adapted to study cytotoxic T cell CD107a exocytosis by gating CD3+CD8 +CD57+ cells after TCR engagement with P815 and anti-CD3 antibody. Here we present data comparing 92 patients with variants in genes affecting exocytosis function against 58 other PID patients diagnosed over 10 years from one center. NK and cytotoxic T cell exocytosis was tested on all patient samples. The anti-CD3T cell test returns superior sensitivity and specificity of 97.8% and 94.7% while the K562 NK test a sensitivity of 86.7% and specificity of 96.1%. The anti-CD 16 NK test was found comparable to the T cell test with values of 97.8% and 93.4%. The data was additionally juxtaposed against 63 patients with secondary HLH, 198 healthy adult donors, and 84 transport controls, all giving similar results of high accuracy. We further stratified the data by time taken between venipuncture and arrival at the testing laboratory and found that control samples up to 36 hours old showed comparable function to < 24 hours old samples. This is important as transporting samples from remote primary care centers often cannot be accomplished within 24 hours.While all three exocytosis tests return superior diagnostic sensitivity, we find the anti-CD3 antibody induced exocytosis of T cells and the anti-CD16 antibody induced exocytosis of NK cells more accurate than the current standard K562 cell stimulation for the diagnosis of PIDs affecting cytotoxic lymphocyte exocytosis. Evaluating T cells alongside NK cells acts as a confirmatory test and buffers against technical failures and the lack of NK cells which can be seen in lymphopenic patients. These assays with improved sensitivity may help us better understand PIDs that partially impair exocytosis.

Primary immunodeficiencies (PID) Life Index in Southeast Asia: A comparative analysis of PID Principles of Care (PoC).

To analyze the implementation of the Principles of Care (PoC) in primary immunodeficiencies (PID) in Southeast Asia (SEA) countries - six years after its call of action. Using the newly developed PID Life Index software, the index of implementation of principles of care in the management of PIDs patients involving the six participating SEA countries (Cambodia, Indonesia, Malaysia, Vietnam, Thailand, and Philippines) were extracted. For each of the six separate principles, the index from the six countries will be compared and presented based on the calculated index. Comparative analysis of the six principles of care of PID in the SEA countries showed low diagnostic rate with minimal availability of diagnostic tests options. Generally, almost all SEA countries provide curative treatments, vaccines, and anti-infectious therapies although the reimbursement scheme varied in relieving patients' financial burden. We also highlighted the active involvement of patient organizations in SEA, with main areas of work focused on advocacy and increasing awareness among public and healthcare professionals. It is applaudable that the SEA continent is gradually strengthening its work in management of PID, especially in Thailand and Vietnam. However, more emphasis must be placed among stakeholders in SEA countries towards successful implementation of the PoC for a holistic management of PID patients.

Specific Cellular and Humoral Immune Responses to the Neoantigen RBD of SARS-CoV-2 in Patients with Primary and Secondary Immunodeficiency and Healthy Donors

Patients with antibody deficiency disorders, such as primary immunodeficiency (PID) or secondary immunodeficiency (SID) to B-cell lymphoproliferative disorder (B-CLPD), are two groups vulnerable to developing the severe or chronic form of coronavirus disease caused by SARS-CoV-2 (COVID-19). The data on adaptive immune responses against SARS-CoV-2 are well described in healthy donors, but still limited in patients with antibody deficiency of a different cause. Herein, we analyzed spike-specific IFN-γ and anti-spike IgG antibody responses at 3 to 6 months after exposure to SARS-CoV-2 derived from vaccination and/or infection in two cohorts of immunodeficient patients (PID vs. SID) compared to healthy controls (HCs). Pre-vaccine anti-SARS-CoV-2 cellular responses before vaccine administration were measured in 10 PID patients. Baseline cellular responses were detectable in 4 out of 10 PID patients who had COVID-19 prior to vaccination, perceiving an increase in cellular responses after two-dose vaccination (p < 0.001). Adequate specific cellular responses were observed in 18 out of 20 (90%) PID patients, in 14 out of 20 (70%) SID patients and in 74 out of 81 (96%) HCs after vaccination (and natural infection in some cases). Specific IFN-γ response was significantly higher in HC with respect to PID (1908.5 mUI/mL vs. 1694.1 mUI/mL; p = 0.005). Whereas all SID and HC patients mounted a specific humoral immune response, only 80% of PID patients showed positive anti-SARS-CoV-2 IgG. The titer of anti-SARS-CoV-2 IgG was significantly lower in SID compared with HC patients (p = 0.040), without significant differences between PID and HC patients (p = 0.123) and between PID and SID patients (p =0.683). High proportions of PID and SID patients showed adequate specific cellular responses to receptor binding domain (RBD) neoantigen, with a divergence between the two arms of the adaptive immune response in PID and SID patients. We also focused on the correlation of protection of positive SARS-CoV-2 cellular response to omicron exposure: 27 out of 81 (33.3%) HCs referred COVID-19 detected by PCR or antigen test, 24 with a mild course, 1 with moderate symptoms and the remaining 2 with bilateral pneumonia that were treated in an outpatient basis. Our results might support the relevance of these immunological studies to determine the correlation of protection with severe disease and for deciding the need for additional boosters on a personalized basis. Follow-up studies are required to evaluate the duration and variability in the immune response to COVID-19 vaccination or infection.