BACKGROUND:Patients with partial DiGeorge syndrome (pDGS) can present with immune dysregulation, the most common being autoimmune cytopenia (AIC). There is a lack of consensus on the approach to type, combination, and timing of therapies for AIC in pDGS. Recognition of immune dysregulation early in pDGS clinical course may help individualize treatment and prevent adverse outcomes from chronic immune dysregulation. OBJECTIVES:Objectives of this study were to characterize the natural history, immune phenotype, and biomarkers in pDGS with AIC. METHODS:Data on clinical presentation, disease severity, immunological phenotype, treatment selection, and response for patients with pDGS with AIC were collected via retrospective chart review. Flow cytometric analysis was done to assess T and B cell subsets, including biomarkers of immune dysregulation. RESULTS:Twenty-nine patients with the diagnosis of pDGS and AIC were identified from 5 international institutions. Nineteen (62%) patients developed Evan's syndrome (ES) during their clinical course and twenty (69%) had antibody deficiency syndrome. These patients demonstrated expansion in T follicular helper cells, CD19hiCD21lo B cells, and double negative cells and reduction in CD4 naïve T cells and regulatory T cells. First-line treatment for 17/29 (59%) included corticosteroids and/or high-dose immunoglobulin replacement therapy. Other overlapping therapies included eltrombopag, rituximab, and T cell immunomodulators. CONCLUSIONS:AIC in pDGS is often refractory to conventional AIC treatment paradigms. Biomarkers may have utility for correlation with disease state and potentially even response to therapy. Immunomodulating therapies could be initiated early based on early immune phenotyping and biomarkers before the disease develops or significantly worsens.

Introduction: Diagnostic criteria for Autoimmune Lymphoproliferative Syndrome (ALPS) is based on clinical, laboratory and genetic findings. The underlying pathomechanisms are largely related to defects in the lymphocyte apoptosis pathways (FAS, FAS ligand, or CASP10) but other combined immunodeficiencies may also present with ALPS-like features (e.g. CASP8, NFKB1, CTLA4, ALP1). Clinically, patients often present with progressive autoimmune cytopenias and treatment relies on T cell immune modulation. Hereby, we present diagnostic and treatment challenges in a pediatric patient with ALPS-like phenotype with rapid decline during an episode of severe autoimmune hemolytic anemia.

Activated PI3K delta syndrome (APDS) is a rare inborn error of immunity (IEI) due to a heterozygous gain-of-function mutation in the PIK3CD or PIK3R1 genes. APDS patients have high variability in clinical manifestations including recurrent sinopulmonary infections, lymphoproliferation, and susceptibility to CMV and/or EBV viremia. APDS is characterized by a block in B-cell development to follicular stage. Therefore, increase in transitional compartment is almost exclusively seen in untreated APDS patients. We describe a family that present with APDS-like clinical and laboratory findings, while harboring a novel variant in ATP binding cassette subfamily B member 1 (ABCB1), which is involved in adenosine salvage and mTORC1 pathways. Retrospective chart review was performed for clinical and laboratory data. Extensive immune phenotyping was obtained. Genetic evaluation included targeted immune panel and whole exome sequencing. Mitotracker-green detection by flow cytometry was used to determine progression to follicular B cell stage. Index case is a 14-year-old female with a complex presentation of infectious and non-infectious complications notable for lifelong hypogammaglobulinemia with poor vaccine response, multiple intubations for upper respiratory illnesses, bronchiectasis, and short stature. Patient had 3 other siblings who also had similar presentation with varied severity, including features of short stature, recurrent infections, alopecia universalis and immune dysregulation. Three siblings required immunoglobulin replacement therapy. Extensive immune-phenotyping revealed significant expansion of CD24hiCD38hi transitional and CD19hiCD21lo B-cells, with decrease in follicular and memory B-cell compartment in all. Although clinical and lab findings prompted APDS diagnosis, repeated targeted genetic panel testing did not show variants in PIK3CD or PIK3R1. Consequent whole exome sequencing revealed a candidate variant in ABCB1 p.Ala1187Thr that was shared among all. Interestingly, surface expression of ABCB1 was significantly elevated in patients compared to healthy controls. Initial functional testing showed disruption in mitochondrial efflux, further supporting the block from transitional to follicular stage. Determining diagnostic approaches in APDS-like disorders liked to ABCB1 variant is challenging, especially when pathogenesis is yet to be determined. Although further functional testing of ABCB1 and its potential role in PI3K signaling is needed, ABCB1 gene may play an important role in APDS pathology.

Introduction: Nuclear factor kappa B subunit 1 (NFKB1) gene plays an essential role in immune cell signaling. Heterozygous NFKB1 variants are the most common cause of Common Variable Deficiency (CVID). Patients are susceptible to recurrent infections and non-infectious complications often requiring immune modulation. Intrafamilial variability of clinical phenotypes causes challenges in diagnosis and determining personalized treatment strategies. We describe a family with a novel NFKB1 variant and challenges in diagnostic and treatment approaches.

Clinicians are faced with evaluating real and alleged reactions to foods that may be allergic or nonallergic. Pathogenesis, diagnosis, and treatment of various non-IgE-mediated diseases are discussed in this review. These food-related conditions range from mild to severe. Referral for an allergy workup may be pursued despite the lack of IgE-mediated symptoms. Diagnostic testing is available for defined non-IgE-mediated food diseases that are either immunologic or nonimmunologic. These include celiac disease and related disorders, carbohydrate maldigestion, pancreatic insufficiency, and histamine intolerance. In contrast, there is a paucity of definitive studies to prove food intolerance diseases. There are no definitive diagnostic criteria or testing for nonceliac gluten sensitivity. Functional gastrointestinal disorders, such as irritable bowel syndrome, are better stratified diagnostically but still lack reliable testing. Both nonceliac gluten sensitivity and irritable bowel syndrome are linked to dietary triggers including fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Therefore, dietary alteration alone may be diagnostic and therapeutic when all other conditions are ruled out. These conditions are important considerations when evaluating a patient with history of a food reaction. There is little evidence that foods are causative in other ailments such as acne, migraines, and nasal congestion and hypersecretion.

Inborn errors of immunity (IEI) may present with immune dysregulation due to a variety of impairments in tolerance mechanisms. Several lymphocyte subsets have been proposed as biomarkers for immune dysregulation, but their importance in pathomechanisms and monitoring disease activity is unclear. Patients with IEI linked to immune dysregulation were enrolled through referrals and/or from our Jeffrey Modell Foundation registry (over 850 cases [2016 to 2022]). Peripheral blood samples were tested by flow cytometry for biomarkers of immune dysregulation including TCRab CD4-CD8- (DN), T follicular helper (Tfh), regulatory T (Treg) and CD19hiCD21lo B cell subsets. Forty-one IEI patients were identified with ALPS (n=4) or variants in CTLA4 (n=16), NFKB1 (n=9), PI3K (n=8), RAG (n=1) and 22q11del (n=3). Extensive immune phenotyping was available for 78 timepoints from 31 of 41 patients. Compared to healthy donors, expansion was noted in Tfh (52 timepoint; 26 patients), CD19hiCD21lo B (36 timepoints; 21 patients) and DN (32 timepoints; 19 patients) cell populations. A reduction in Treg compartment was observed (42 timepoints; 23 patients). The relative contribution of the four biomarker subsets in specific disorders were variable. Notable was the dual expansion of Tfh and CD19hiCD21lo B cells in patients with NFKB1 variant, whereas DN T cells correlated with Tfh expansion only in CTLA4 deficient patients. Our study investigates the utility of cellular biomarkers of immune dysregulation. Recognition of specific subsets of immune dysregulation may help monitor disease activity and individualize treatment strategies in IEI.

COVID-19 related encephalitis has been reported in pediatric patients; however, there are no reports in patients with inborn errors of immunity (IEI). Activated PI3K Delta Syndrome (APDS) is a disease of immune dysregulation with immunodeficiency, autoimmunity, and abnormal lymphoproliferation resulting from autosomal dominant gain-offunction variants in PIK3CD or PIK3R1 genes. We investigate a family with APDS, one mother and three children, one of whom developed COVID-19 related encephalitis. Patients were consented to an IRB-approved protocol at our institution. Medical records and detailed immunophenotyping were reviewed. Family members were sequenced for IEI with a targeted gene panel. The index case is a 10-year-old female with a known pathogenic variant in PIK3CD (c.3061 G > A, p.Glu1021Lys), who contracted SARS-COV-2 despite one COVID-19 vaccination in the series. Her disease course included COVID-related encephalitis with cerebellitis and compression of the pons, resulting in lasting truncal ataxia and cerebellar mutism. At that time, the patient was not on immunoglobulin replacement therapy (IgRT), but was receiving Sirolimus. Besides the index case, 3 family members (2 brothers, 1 mother) also share the same PIK3CD variant with variable clinical and immunological phenotypes. All children exhibited high transitional B-cells, consistent with developmental block to follicular B cell stage. Increased non-class switched IgM+ memory B cells and skewing towards CD21lo B cell subset, which is considered autoreactive-like, was observed in all patients. Of note, the patient had low plasmablasts, but normal immunoglobulins. Of her family members, only one was receiving both sirolimus and IgRT. We describe a rare case of COVID-19-related encephalitis in a patient with inborn error of immunity while not on IgRT. This may indicate infection susceptibility because of a lack of sufficient immunity to SARS-CoV-2, unlike the rest of her family with the same PIK3CD variant.

Introduction: Autoimmune cytopenias (AICs) occur in the setting of immune dysregulation and autoimmunity. AICs are known to precede the classical presentation and subsequent diagnosis of primary immunodeficiency disorders (PIDs) in some cases, with a PID spectrum involving B, T, and Treg dysregulation. Conversely, PID patients are also at a markedly increased risk of AICs and patients co-diagnosed with AICs and PIDs face higher mortality rates likely due to delayed diagnosis or improper/delayed therapy. Further, co-diagnosed patients are often refractory to standard treatment. Early screening and diagnosis of PIDs in the setting of AICs could lead to more targeted therapies and potentially better patient outcomes. We intend to investigate biomarkers that differentiate immune dysregulation among those with or without PID in the setting of AIC. Methods: A retrospective analysis comparing clinical history, including symptoms, presence of PID, genetic testing and diagnosis and treatment outcomes was performed on AIC patients in our hospital from 2016 to 2019. We also performed extensive immune phenotyping by flow cytometric analysis. Patients with expansion of CD19hi CD21lo B cells were further evaluated for Tbet+ CD11chi features for potential autoreactivity. Results: Our original cohort of 103 AIC patients included patients who were diagnosed with AIC only (n=52) or co-diagnosed with AIC-PID (n=51). From this cohort, a total of 43 were evaluated for further immune phenotyping, including 35 AIC-PID patients and 8 AIC only patients. Of the AIC-PID patients, 23 (65.7%) had a genetically coded PID, including pathogenic variants in CTLA4, NFKB1, PI3K or partial DiGeorge, while 12 (34.3%) were diagnosed with CVID/CID. Flow cytometry analysis revealed significantly increased T-follicular helper cell (Tfh) population in the AIC-PID group compared to AIC only (p=0.03) and healthy donor (HD) (p=0.004). We saw a similar expansion of CD19hi CD21lo B cells within the AIC-PID group. Conversely, patients with AIC-PID had decreased percentage of T-regulatory cells (Tregs) when compared to AIC only and HD groups. These differences were amplified within the genetically coded AIC-PID patients in Treg and Tfh populations and maintained in CD19hi CD21lo B cells. Further investigation of clinical history within the symptomatic, genetically coded AIC-PID group yielded 3 (33.3%) patients responsive to treatment and 6 (66.7%) patients unresponsive or partially responsive to therapy. Interestingly, nonresponsive patients showed an increased percentage of CD19hi CD21lo B cells. Conclusions: Our analysis demonstrates the potential utility of biomarkers, notably CD19hi CD21lo B cells and their immunological function for detecting underlying PIDs within the setting of AIC patients. Though this B cell population needs further assessment regarding Tbet and CD11c expression, with studies ongoing, these biomarkers may lead to a screening methodology to increase clinical visibility and detection as well as hasten diagnosis of underlying PID and potentially predict response to therapy, therefore increasing effective treatment outcomes for patients co-diagnosed with AIC PID.

Bone marrow fibrosis (BMF) is a histopathological finding appreciated in a multitude of conditions such as myeloproliferative diseases and malignant neoplasms, along with autoimmune disorders. Autoimmune myelofibrosis (AIMF) is a particularly uncommon etiology of benign BMF. AIMF may be primary with serologic evidence of autoantibodies or secondary to an underlying autoimmune disease. The authors aim to emphasize the importance of distinguishing between primary versus secondary causes owing to significant prognostic and therapeutic discrepancies and in hopes of expediting the diagnostic journey. Research has recommended a treatment strategy of high-dose steroids followed by a steroid taper. However, our patient responded positively to a short course of high-dose steroids and intravenous immunoglobulins (IVIG) as evidenced by an improvement in cytopenias and bone marrow fibrosis grading. This outcome warrants further research on the necessity of steroid tapers in AIMF.