Recurrent Bacterial Infections Research Articles

Structural basis for EROS binding to human phagocyte NADPH oxidase NOX2

Essential for reactive oxygen species (EROS) protein is a recently identified molecular chaperone of NOX2 (gp91phox), the catalytic subunit of phagocyte NADPH oxidase. Deficiency in EROS is a recently identified cause for chronic granulomatous disease, a genetic disorder with recurrent bacterial and fungal infections. Here, we report a cryo-EM structure of the EROS-NOX2-p22phox heterotrimeric complex at an overall resolution of 3.56Å. EROS and p22phox are situated on the opposite sides of NOX2, and there is no direct contact between them. EROS associates with NOX2 through two antiparallel transmembrane (TM) α-helices and multiple β-strands that form hydrogen bonds with the cytoplasmic domain of NOX2. EROS binding induces a 79° upward bend of TM2 and a 48° backward rotation of the lower part of TM6 in NOX2, resulting in an increase in the distance between the two hemes and a shift of the binding site for flavin adenine dinucleotide (FAD). These conformational changes are expected to compromise superoxide production by NOX2, suggesting that the EROS-bound NOX2 is in a protected state against activation. Phorbol myristate acetate, an activator of NOX2 in vitro, is able to induce dissociation of NOX2 from EROS with concurrent increase in FAD binding and superoxide production in a transfected COS-7 model. In differentiated neutrophil-like HL-60, the majority of NOX2 on the cell surface is dissociated with EROS. Further studies are required to delineate how EROS dissociates from NOX2 during its transport to cell surface, which may be a potential mechanism for regulation of NOX2 activation.

Qualitative Immunoglobulin Deficiency Causes Bacterial Infections in Patients with STAT1 Gain-of-Function Mutations.

STAT1 is a transduction and transcriptional regulator that functions within the classical JAK/STAT pathway. In addition to chronic mucocutaneous candidiasis, bacterial infections are a common occurrence in patients with STAT1 gain-of-function (GOF) mutations. These patients often exhibit skewing of B cell subsets; however, the impact of STAT1-GOF mutations on B cell-mediated humoral immunity remains largely unexplored. It is also unclear whether these patients with IgG within normal range require regular intravenous immunoglobulin (IVIG) therapy. Eleven patients (harboring nine different STAT1-GOF mutations) were enrolled. Reporter assays and immunoblot analyses were performed to confirm STAT1 mutations. Flow cytometry, deep sequencing, ELISA, and ELISpot were conducted to assess the impact of STAT1-GOF on humoral immunity. All patients exhibited increased levels of phospho-STAT1 and total STAT1 protein, with two patients carrying novel mutations. In vitro assays showed that these two novel mutations were GOF mutations. Three patients with normal total IgG levels received regular IVIG infusions, resulting in effective control of bacterial infections. Four cases showed impaired affinity and specificity of pertussis toxin-specific antibodies, accompanied by reduced generation of class-switched memory B cells. Patients also had a disrupted immunoglobulin heavy chain (IGH) repertoire, coupled with a marked reduction in the somatic hypermutation frequency of switched Ig transcripts. STAT1-GOF mutations disrupt B cell compartments and skew IGH characteristics, resulting in impaired affinity and antigen-specificity of antibodies and recurrent bacterial infections. Regular IVIG therapy can control these infections in patients, even those with normal total IgG levels.

Investigation on the treatment of empagliflozin in glycogen storage disease type Ib

Objective: To investigate the safety, efficacy and effective dose of empagliflozin in the treatment of glycogen storage disease type Ⅰb (GSD Ⅰb). Method: This was a cross sectional study. A total of 28 children with GSDⅠb who started oral empagliflozin treatment from January 2021 to June 2023 in the WeChat group of patients with glycogen storage disease were selected as the study objects. Clinical data such as general situation, current situation of medication and adverse reactions of the children were collected through questionnaires from June 18 to 30, 2023. The differences of symptoms and laboratory tests before and after empagliflozin treatment were compared by using paired chi-square test and Wilcoxon signed rank sum test. Results: Totally 28 children with GSD Ⅰb were from 12 different provinces, autonomous regions and municipalities in China. There were 14 males and 14 females, Empagliflozin treatment was started at the age of 4.8(2.4, 10.8) years, the time of treatment was 14.5(11.3, 21.5) months, the initial dosage was (0.23±0.11) mg/(kg·d), and the maintenance dosage was (0.28±0.12) mg/(kg·d). Empagliflozin showed positive effects on neutropenia, severity of inflammatory bowel disease like symptoms(Z=-3.70, -2.65, both P<0.05), The proportion of recurrent oral ulcers, recurrent bacterial infections and anemia was significantly lower than that before medication 18% (5/28) vs. (46% (13/28), 14% (4/28) vs. 46% (13/28), 21% (6/28) vs. 46% (13/28), χ²=4.05, 5.26, 3.05, all P<0.05). GCSF was once used in 5 children with GSD Ⅰb, all of them had completely stopped GCSF after empagliflozin treatment. The most common adverse events during empagliflozin treatment were hypoglycemia (5 children) and urinary infection (3 children). All 28 patients had no serious adverse reactions. Conclusions: Empagliflozin can increase the neutrophil count of children with GSD Ⅰb, and had a favorable effect on symptoms such as recurrent oral ulcers, and recurrent infection. The common adverse events during empagliflozin treatment were hypoglycemia and urinary infection.

Different profiles of acute graft pyelonephritis among kidney recipients from standard or elderly donors.

Acute graft pyelonephritis (AGPN) is a relatively common complication in kidney transplants (KTs); however, the effects on allograft function, diagnostic criteria, and risk factors are not well established. Retrospective analysis of all consecutive adult KTs was performed between 01 January 2011 and 31 December 2018 (follow-up ended on 31 December 2019) to examine the association between the diagnosis of AGPN (confirmed with magnetic resonance imaging [MRI]) during the first post-transplantation year and graft outcomes. Among the 939 consecutive KTs (≈50% with donors ≥60 years), we identified 130 MRI-confirmed AGPN episodes, with a documented association with recurrent and multidrug-resistant bacterial urinary tract infections (UTIs) (p < 0.005). Ureteral stenosis was the only risk factor associated with AGPN (OR 2.9 [95% CI, 1.6 to 5.2]). KTs with AGPN had a decreased allograft function at the first year (ΔeGFR 6 mL/min/1.73 m2 [-2-15] in non-AGPN vs. -0.2 [-6.5-8.5] in AGPN, p < 0.001), with similar and negative profiles in KTs from standard or elderly donors. However, only KTs with AGPN and a donor <60 years showed reduced death-censored graft survival (p = 0.015); most of this subgroup received anti-thymocyte globulin (ATG) induction (40.4% vs. 17.7%), and their MRI presented either a multifocal AGPN pattern (73.9% vs. 56.7%) or abscedation (28.3% vs. 11.7%). No difference was noted in death-censored graft survival between early (<3 months post-KT) or late (3-12 months) AGPN, solitary/recurrent forms, or types of multidrug-resistant pathogens. Linear regression confirmed the independent role of multifocal pattern, abscedation, ATG induction, and donor age on the eGFR at the first year. AGPN, influenced by multifocal presentation, ATG induction, donor age, and abscedation, affects kidney function and significantly impacts allograft survival in KTs with donors <60 years.

Catalase-templated nanozyme-loaded microneedles integrated with polymyxin B for immunoregulation and antibacterial activity in diabetic wounds

Diabetic wounds are characterized by chronic trauma, with long-term non-healing attributed to persistent inflammation and recurrent bacterial infections. Exacerbation of the inflammatory response is largely due to increased levels of reactive oxygen species (ROS). In this study, catalase (CAT) was used as a biological template to synthesize nanozyme-supported natural enzymes (CAT-Mn(SH)x) using a biomimetic mineralization method. Subsequently, polymyxin B (CAT-Mn(SH)x@PMB) was immobilized on its surface through electrostatic assembly. CAT-Mn(SH)x@PMB demonstrates the ability for slow and sustained release of hydrogen sulfide (H2S). Finally, CAT-Mn(SH)x@PMB loaded microneedles (MNs) substrate were synthesized using polyvinyl alcohol (PVA) and hydroxyethyl methacrylate (HEMA), and named CAT-(MnSH)x@PMB-MNs. It exhibited enhanced enzyme and antioxidant activities, along with effective antibacterial properties. Validation findings indicate that it can up-regulate the level of M2 macrophages and reduce the level of pro-inflammatory cytokine tumor necrosis factor-α (TNF-α). Additionally, it promotes angiogenesis and rapid nerve regeneration, thereby facilitating wound healing through its dual anti-inflammatory and antibacterial effects. Hence,this study introduces a time–space tissue-penetrating and soluble microneedle patch with dual anti-inflammatory and antibacterial effects for the treatment of diabetic wounds.

Effect of Different Induction Immunosuppression on the Incidence of Infectious Complications after Kidney Transplantation-Single Center Study.

Background/Objectives: Potent immunosuppression lowers the incidence of acute graft rejection but increases the risk of infections. In order to decrease either infectious complications or acute rejection, it is necessary to identify risk groups of patients profiting from personalized induction immunosuppressive treatment. The aim of our analysis was to find whether there were higher incidences of infectious complications after kidney transplantation (KT) in groups with different induction immunosuppressive treatment and also to find independent risk factors for recurrent infections. Materials: We retrospectively evaluated all patients with induction treatment with basiliximab after kidney transplantation from 2014 to 2019 at our center relative to age- and sex-matched controls of patients with thymoglobulin induction immunosuppression. Results: Our study consisted of two groups: basiliximab (39) and thymoglobulin (39). In the thymoglobulin group we observed an increased incidence of recurrent infection in every observed interval; however, acute rejection was seen more often in the basiliximab group. A history of respiratory diseases and thrombocytopenia were identified as independent risk factors for recurrent bacterial infections from the first to sixth month after KT. Decreased eGFR from the first month, infections caused by multi-drug-resistant bacteria, and severe infections (reflected by the need for hospitalization) were identified as independent risk factors for recurrent bacterial infections from the first to the twelfth month after KT. Conclusions: We found that in the group of patients with thymoglobulin induction immunosuppressive treatment, infectious complications occurred significantly more often during the entire monitored period with decreased incidence of acute humoral and cellular rejection occurred more often.

Successful Treatment of Severe Aplastic Anemia with Hematopoietic Stem Cell Transplantation in the Setting of Active Mucormycosis.

Severe aplastic anemia (SAA) is a life-threatening hematological disease characterized by the suppression of the bone marrow. Patients with SAA are predisposed to recurrent bacterial infections and invasive fungal infections (IFI) due to profound and persistent neutropenia. Mucorales are the second most common cause of IFI encountered in SAA. Here we present a pediatric case of SAA with active mucormycosis infection of the paranasal sinuses. In the first step, surgical debridement was performed and combined antifungal therapy (liposomal amphotericin B, posaconazole, caspofungin) was started. Due to severe neutropenia, daily granulocyte transfusion was added to therapy. Hyperbaric oxygen therapy was applied for wound healing. After all this the patient went under flap surgery. One week after the successful flap procedure, HSCT was performed and he had no complications related to HSCT. The patient was followed in the outpatient clinic for 6months with posaconazole. Now, he is out of drugs and followed without problems for 15months after HSCT. Our case confirms that urgent HSCT with multiple therapies (surgical debridement, granulocyte support, combined antifungal therapy, hyperbaric O2) is crucial for saving life in SAA patients with active mucormycosis.

Nijmegen syndrome in childhood: a clinical case

Nijmegen syndrome is a rare monogenic pathology with an autosomal recessive type of inheritance. The disease is manifested by congenital developmental anomalies and microcephaly, primary immunodeficiency, frequent recurrent viral and bacterial infections, retardation in physical and neuropsychic development. In the medical literature, 150 cases of the syndrome are described; pathology occurs more often among the Slavic population. Nijmegen syndrome belongs to a group of diseases with chromosomal instability. The pathogenetic feature of the syndrome is congenital immunodeficiency of the humoral (B-lymphocytes) and cellular (T-lymphocytes) components. According to statistics, 40 % of children with Nijmegen syndrome are diagnosed with malignant neoplasms. lymphoid tissue is more often affected (non-Hodgkin’s B and T-cell lymphomas, acute lymphoblastic leukemia), and the development of solid neoplasia is also possible. To diagnose Nijmegen syndrome, in addition to assessing the patient clinical status, it is necessary to conduct an extended immunological examination with the determination of immunoglobulins A, M, G and molecular genetic studies.The article presents a clinical case of diagnosis and treatment of Nijmegen syndrome in childhood.

Achieving Consensus: Severity-Graded Definitions of Fontan-Associated Complications to Characterize Fontan Circulatory Failure

BackgroundFontan physiology leads to chronic changes in other organ systems that may affect long-term survival and the success of heart transplantation. Inadequate assessment and treatment of the extra-cardiac effects of Fontan may contribute to poor outcomes. Severity-graded/ordinal consensus definitions of Fontan complications are lacking, which limits understanding of how Fontan-specific morbidity affects patients’ outcomes. Methods and ResultsA panel of Fontan patient and physiology experts, including pediatric, adult congenital, heart failure, and critical-care cardiology as well as pediatric nephrology, hepatology and psychology, convened to develop definitions of Fontan complications. Definitions were created by using a severity-graded ordinal scale: grade 1, mild; grade 2, moderate; grade 3, severe; grade 4, disabling or life threatening. Following definition creation, a second panel of 21 experts in Fontan circulatory failure used a modified Delphi methodology to modify and vote on definitions until consensus (> 90% agreement without recommended further modification) was reached on final definitions. After 3 rounds of modifications and voting, consensus agreement was achieved on all Fontan-specific definitions. The defined complications and morbidities of Fontan include: anatomic Fontan pathway obstruction, cyanosis, systemic venous abnormalities resulting from venous insufficiency, atrial arrhythmia, ventricular arrhythmia, bradycardia, chronic pleural effusions, chronic ascites, protein-losing enteropathy, plastic bronchitis, hemoptysis and pulmonary hemorrhage, sleep apnea, Fontan-associated liver disease, portal and hepatic variceal disease, acute kidney injury affecting clinical treatment, polycythemia, thrombotic disease, recurrent or severe bacterial infection, skin atrophy, adrenal insufficiency, physical impact of previous stroke, mood/behavior disorder, and neurodevelopmental disorder. ConclusionConsensus and severity-graded definitions of Fontan-specific cardiac and extra-cardiac complications were achieved and are available for use in research. They will allow future robust analyses of Fontan patient outcomes.

Epidemiological insights into seasonal, sex‑specific and age‑related distribution of bacterial pathogens in urinary tract infections.

Urinary tract infections (UTIs) are prevalent and recurrent bacterial infections that affect individuals worldwide, posing a significant burden on healthcare systems. The present study aimed to explore the epidemiology of UTIs, investigating the seasonal, gender-specific and age-related bacterial pathogen distribution to guide clinical diagnosis. Data were retrospectively collected from electronic medical records and laboratory reports of 926 UTIs diagnosed in Fuding Hospital (Fujian University of Traditional Chinese Medicine, Fuding, China). Bacterial isolates were identified using standard microbiological techniques. χ2 tests were performed to assess associations between pathogens and the seasons, sex and age groups. Significant associations were found between bacterial species and seasons. Enterococcus faecium exhibited a substantial prevalence in spring (χ2, 12.824; P=0.005), while Acinetobacter baumannii demonstrated increased prevalence in autumn (χ2, 16.404; P=0.001). Female patients showed a higher incidence of UTIs. Gram-positive bacteria were more prevalent in males, with Staphylococcus aureus showing significant male predominance (χ2, 14.607; P<0.001). E. faecium displayed an age-related increase in prevalence (χ2, 17.775; P<0.001), whereas Escherichia coli tended to be more prevalent in younger patients (χ2, 12.813; P=0.005). These findings highlight the complex nature of UTIs and offer insights for tailored diagnostic and preventive strategies, potentially enhancing healthcare outcomes.

Trained immunity in recurrent Staphylococcus aureus infection promotes bacterial persistence.

Bacterial persister cells, a sub-population of dormant phenotypic variants highly tolerant to antibiotics, present a significant challenge for infection control. Investigating the mechanisms of antibiotic persistence is crucial for developing effective treatment strategies. Here, we found a significant association between tolerance frequency and previous infection history in bovine mastitis. Previous S. aureus infection led to S. aureus tolerance to killing by rifampicin in subsequent infection in vivo and in vitro. Actually, the activation of trained immunity contributed to rifampicin persistence of S. aureus in secondary infection, where it reduced the effectiveness of antibiotic treatment and increased disease severity. Mechanically, we found that S. aureus persistence was mediated by the accumulation of fumarate provoked by trained immunity. Combination therapy with metformin and rifampicin promoted eradication of persisters and improved the severity of recurrent S. aureus infection. These findings provide mechanistic insight into the relationship between trained immunity and S. aureus persistence, while providing proof of concept that trained immunity is a therapeutic target in recurrent bacterial infections involving persistent pathogens.

New Antimicrobial Strategies to Treat Multi-Drug Resistant Infections Caused by Gram-Negatives in Cystic Fibrosis.

People with cystic fibrosis (CF) suffer from recurrent bacterial infections which induce inflammation, lung tissue damage and failure of the respiratory system. Prolonged exposure to combinatorial antibiotic therapies triggers the appearance of multi-drug resistant (MDR) bacteria. The development of alternative antimicrobial strategies may provide a way to mitigate antimicrobial resistance. Here we discuss different alternative approaches to the use of classic antibiotics: anti-virulence and anti-biofilm compounds which exert a low selective pressure; phage therapies that represent an alternative strategy with a high therapeutic potential; new methods helping antibiotics activity such as adjuvants; and antimicrobial peptides and nanoparticle formulations. Their mechanisms and in vitro and in vivo efficacy are described, in order to figure out a complete landscape of new alternative approaches to fight MDR Gram-negative CF pathogens.

MOF-encapsulated copper-doped carbon dots nanozymes with excellent biological activity promote diabetes wound healing.

Poor wound healing in diabetics is primarily caused by persistently high levels of inflammation and recurrent bacterial infections. The catalytic therapy technique based on nanozyme medicine has emerged as a beacon of hope for patients with diabetic wounds. However, the use of a single-atom nanozyme may still have limitations, including nanozyme burst release, immunological clearance and insufficient antibacterial activity. To address the aforementioned problems, we provide a new nano-catalytic therapeutic agent for diabetic skin ulcers that incorporates a single-atom nanozyme with high antioxidant activity into a metal-organic framework (ZIF-Cu/C-dots). First, a Cu single-atom nanozyme supported by ultra-small carbon dots (Cu/C-dots) with high antioxidant activity was created. A nanozyme-integrated metal-organic framework was then created, utilizing Cu/C-dots as ligands and Zn2+ as the core metal. Cu/C-dots have good oxidase-like activity, shielding the biological system from ROS damage and reducing the expression of TNF-α and IL-1β. Zn2+ also has good antibacterial activity (the antibacterial rate was more than 90%). This integrated technique prevents nanozyme aggregation, improves nanozyme biocompatibility, slows down the breakdown of ZIF and allows for the regulated release of Cu/C-dots and Zn2+ as needed. Finally, in vivo studies have shown that ZIF-Cu/C-dots can effectively alleviate inflammation at the site of diabetic wounds, accelerate vascular regeneration, promote collagen deposition and enhance tissue remodeling, serving as a novel nano-catalytic platform for the treatment of wounds that are difficult to heal.

Immunodeficiency 70 (IMD 70)

Background: Immunodeficiency 70 is a rare disease and there are only very few cases in the literature. Case History: Young boy in his early 20’s from Indian subcontinent presented with recurrent episodes of fever, oral ulcers, loss of weight for past 3 years. Four episodes (july 2019, april 2020, APRIL 2021, Jan 2022) of fever, each high grade associated with chills, rigor, nausea, myalgia, throat pain, holo-cranial headache, painful oral ulcers over the tongue and painless over lips. Initial episode of fever was associated with leucopenia (3200) and thrombocytopenia (122000), acute kidney injury (creatinie-3.0) and pyelonephritis, transaminitis. He received 2 weeks of parenteral antibiotics and improved. Subsequent episodes of fever is not associated with any localizing symptoms or signs. No history Suggestive of connective tissue disease. Family history was non contributory. Physical examination: He was febrile (101 degree F), pulse rate 100/minute, respiratory rate 18/minute, tongue ulceration in lateral border, no lymphadenopathy, no organomegaly, normal sytemic examination. Evaluation: The patient was evaluated for chronic infections, hematalogical malignancy, Behcet’s disease, auto inflammatory syndromes like Haplo insufficiency of A20. His complete blood count, electrolytes, renal function test, liver function test urine microscopy, blood culture were normal. CRP was elevated (58 mg/l). Tzanck smear from buccal mucosa was negative. CT thorax and abdomen showed no significant lymphadenopathy, organomegaly, evidence of infections or malignancy. In view of oral ulcers &amp; fever Behcet’s disease was considered and HLA b51 was sent and came negative. Exome genome sequencing was done to diagnose immunodeficiency or autoinflammatory syndromes which came positive for immunodeficiency 70. Treatment: He was treated with colchicine and fever subsided and leucopenia improved Discussion: Immunodeficiency-70 (IMD70) is an autosomal dominant immunologic disorder characterized by severe cutaneous warts on the hands, feet, and face, suggesting increased susceptibility to human papillomavirus (HPV) infection. Affected individuals may also have recurrent bacterial infections like pneumonia, boils, sinusitis, as well as feature of autoinflammation, such as colitis, celiac disease, and retinal vasculitis. Laboratory studies show decreased CD4+ T cells and decreased CD19+ B cells; hypogammaglobulinemia, combined T cell and B cell immunodeficiency characterized by decreased CD4+ T cells, decreased CD19+ B cells, recurrent bacterial infections, and severe cutaneous warts on the hands, feet, and face that has material basis in heterozygous mutation in IVNS1ABP on chromosome 1q25.3.

CVID With Unusual Peripheral Mononeuropathy and Associated IL-7 Receptor Mutation.

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency. It is characterized by hypogammaglobulinemia and can present with a broad range of symptoms including recurrent bacterial infections, autoimmunity, and malignancy. Rarely, it has been implicated with peripheral neuropathy. We present a case of CVID with peripheral neuropathy and a pathogenic heterozygous variant of IL-7 receptor gene. The patient is a 38-year-old female with a history of recurrent infections since childhood including pneumonia and sinus infections status post tonsillectomy and sinus surgery. She subsequently developed severe left leg and lower back pain that progressed to left foot drop and decreased sensation over the left leg. She was found to have severe hypogammaglobulinemia and poor polysaccharide and protein response, thus meeting criteria for CVID. Mononeuropathy is a rare finding in CVID. Genetic panel was performed and was significant for a single pathogenic variant in IL-7 receptor. Disruptions in the IL-7 and IL-7 receptor signaling pathway have been associated with autoimmunity such as rheumatoid arthritis and multiple sclerosis. Further investigation is indicated to determine the clinical significance of this variant.

Dual species sphingosine-1-phosphate lyase inhibitors to combine antifungal and anti-inflammatory activities in cystic fibrosis: a feasibility study

Cystic fibrosis (CF) is an autosomal recessive disorder characterized by respiratory failure due to a vicious cycle of defective Cystic Fibrosis Transmembrane conductance Regulator (CFTR) function, chronic inflammation and recurrent bacterial and fungal infections. Although the recent introduction of CFTR correctors/potentiators has revolutionized the clinical management of CF patients, resurgence of inflammation and persistence of pathogens still posit a major concern and should be targeted contextually. On the background of a network-based selectivity that allows to target the same enzyme in the host and microbes with different outcomes, we focused on sphingosine-1-phosphate (S1P) lyase (SPL) of the sphingolipid metabolism as a potential candidate to uniquely induce anti-inflammatory and antifungal activities in CF. As a feasibility study, herein we show that interfering with S1P metabolism improved the immune response in a murine model of CF with aspergillosis while preventing germination of Aspergillus fumigatus conidia. In addition, in an early drug discovery process, we purified human and A. fumigatus SPL, characterized their biochemical and structural properties, and performed an in silico screening to identify potential dual species SPL inhibitors. We identified two hits behaving as competitive inhibitors of pathogen and host SPL, thus paving the way for hit-to-lead and translational studies for the development of drug candidates capable of restraining fungal growth and increasing antifungal resistance.

Unraveling the Natural History of Good’s Syndrome: A Progressive Adult Combined Immunodeficiency

Good's syndrome (GS) is a rare immune deficiency described almost 6 decades ago. Despite numerous published individual case reports and data collected in cross-sectional studies of small cohorts, the natural history and long-term outcomes of this disease remain unknown. We aimed to determine the clinical and laboratory evolution of 8 adults diagnosed with GS and consecutively evaluated between 1983 and2023. In this prospective, longitudinal cohort study, newly diagnosed patients with GS were followed through repeated measures of clinical, immune, and hematologic changes, as well as targeted genetic screening. All patients reported a healthy childhood and adolescence with symptom onset during the third or fourth decade of life. All presented to our center with recurrent bacterial sinopulmonary infections, thymoma, hypogammaglobulinemia, and absence of B cells. The median age of GS diagnosis was 57 years. During follow-up, immunoglobin replacement therapy effectively minimized sinopulmonary infections. However, the majority experienced severe and systemic viral or fungal infections, 3 developed basal cell carcinomas, and 5 had progressive bronchiectasis and persistent splenomegaly. The most notable clinical feature was opportunistic infections and invitro evidence of cellular immune deficiency, which resulted in the death of 2 individuals. We also report a statistically significant, multidecade progressive decline in lymphocytes, platelets, hemoglobin, and red blood cells in our cohort, suggesting gradual bone marrow failure. Knowledge of the unique phenotype and temporal evolution of GS has allowed us to develop a more comprehensive diagnostic framework. It can be investigated as part of broader research into disease pathophysiology.

Positive impact of sulfamethoxazole-trimethoprim prophylaxis on prevention of severe infections in a patient with glycogen storage disease type Ib

ObjectiveGlycogen storage disease type Ib (GSD-Ib) is a very rare disease complicated by neutropenia with consequent recurrent bacterial infections. Treatment with Filgrastim is not always effective.The low CD4 count observed in our patient is likely the underlying cause of this treatment failure. This low value was previously examined in a small-scale study. Therefore, adding sulfamethoxazole-trimethoprim (SMX-TMP) might be a good strategy.MethodsWe present the case of a male patient with GSD-Ib. He has severe neutropenia (380/mm3) with recurrent infections. Despite neutrophil improvement with Filgrastim, he developed three severe infections requiring hospitalization. Lymphocyte phenotyping showed a deficit in T CD4 + cells (280/mm3) which led us to HIV testing returning negative. Based on this finding we initiated prophylaxis with SMX-TMP.ResultsSince the start of SMX-TMP along with Filgrastim, the patient was not admitted to the hospital for any bacterial infection.ConclusionTo date, no study has examined the significance of incorporating antibiotic prophylaxis for neutropenic patients with GSD-Ib based on CD4 count, akin to the approach of adding SMX-TMP to antiretroviral therapy for HIV patients. Cotrimoxazole is empirically prescribed without assessing the CD4 count or conducting a comparative analysis of the advantages of its addition to Filgrastim. Such practices could potentially exert a significant influence on the disease’s presentation and severity.

Patterns of Outpatient IVIG Use before and during the COVID Pandemic in Patients with Multiple Myeloma

Background: Infections in patients with multiple myeloma are a frequent cause of morbidity and mortality. Intravenous immunoglobulin (IVIG) replacement is a preventative strategy for infection risk reduction. The NCCN guidelines recommend IVIG therapy should be considered in the setting of recurrent serious infection and/or hypogammaglobinemia. The IMWG suggests a targeted use, limiting replacement to patients with IgG concentrations less than 400mg/dl and who have serious recurrent encapsulated bacterial infections. In this study, we sought to describe patterns of IVIG use prior to and during the COVID-19 epidemic. Methods: In this cross-section study, we sought to describe real-world patterns of outpatient IVIG use before and during the COVID-19 pandemic using the IBM MarketScan Commercial Claims and Encounters (CCAE) and Medicare Supplemental and Coordination of Benefits (COB, a.k.a. MDCR) databases. MarketScan is an administrative database of diagnostic and treatment data for more than 30 million commercially insured individuals in the United States. Patients included in this study had private insurance or were enrolled in a Medicare advantage plan. IVIG administration data was grouped by patient age, sex, geographic region, and metropolitan area defined by the Census Metropolitan Statistical Area,. Pre-pandemic time period is defined as the time prior to March 2020. Results: Our study showed changes in patterns of IVIG use with respect to patient age, sex, geographic region, and location of care delivery. A total of 12,893 patients were identified with multiple myeloma during this study period. Patients greater than age 65 made up 31.3% of the cohort. Location of IVIG administration was outpatient hospital (32.6%), Office (40.2%), Patient home (14.9%) and other (0.9%). Pre-pandemic IVIG usage rate in this cohort was 3.37 IVIG administrations per 100 patients studied compared to post-pandemic usage rate increased to 3.6 per 100 patients (p=0.038). A significant increase in utilization is noted by age with usage rate in patients over age 65 increasing from 1.96 to 2.54 (p&amp;lt;0.001). Prior to the pandemic, usage rate for males was 2.2 and increased to 2.51 after the pandemic (p&amp;lt;0.001). For females, usage rate also increased from 2.42 to 2.58 (p=0.07). Changes in utilization also occurred regionally with increased use in the Northeast and West. Usage rates in the Northeast prior to the pandemic were 2.37 compared to 3.28 IVIG administration (p&amp;lt;0.001). Similarly, pre-pandemic utilization rates in the West were 2.55 and increased to 3.21 (p&amp;lt;0.001). Usage rates were stable in the North Central region, only increasing from 2.09 to 2.15 (p=0.54). Interestingly, usage rates decreased slightly in the Southern region from 2.32 to 2.24 post pandemic (p=0.38). Metropolitan service areas saw a slight increase in utilization from 2.41 to 2.56 (p=0.06). However, non-metropolitan service areas had an increase from 2.1 to 2.56 (p&amp;lt;0.001). Conclusions: This study describes the variation in outpatient IVIG use by age, geographic region, sex and location of treatment before and during the COVID-19 pandemic. During the COVID-19 pandemic, there was significant uncertainty regarding optimal infection risk mitigation strategies for patients with multiple myeloma. In this real-world review of clinical practice patterns, variations in outpatient use of IVIG can be seen to vary most based on geographic region and patient age. Statistically significant increases are also seen in males and in non-metropolitan areas. Patients in regions impacted earliest and hardest by increase in COVID-19 infections saw the greatest increase in the use of IVIG while other regions saw stable or decreased utilization. Additionally, patients over age 65, who were at greatest risk for negative outcomes of COVID-19 infections saw the greatest increase in utilization compared to pre-pandemic rates. In the post pandemic time period, patients over age 65 continued to have statistically significant increased rates of utilization while patients less than age 65 also increased rates of utilization that was not statistically significantly increased. This study is limited by lack of clinical information including COVID 19 infection status and concomitant myeloma therapy. The variation in utilization of IVIG illustrates the need for prospective studies to guide its use.

Modeling TCIRG1 Neutropenia By Utilizing Patient Derived Induced Pluripotent Stem Cells

Background: Severe congenital neutropenia (SCN) is a hereditary hematopoietic disorder characterized by recurrent infections and leukemic transformation. We previously identified a novel heterozygous missense mutation (R736S) in TCIRG1 causing SCN in a large multigenerational family (PMID: 24753205). We also identified a statistically significant correlation in individuals with lower ANC with rare missense variants in TCIRG1 in a large cohort of population-based genome screening (PMID: 27229898). Recently, we have discovered another TCIRG1 heterozygousvariant: R736C in two unrelated families with congenital neutropenia. Independently, Shinwari et al identified a novel TCIRG1 mutation, V52L, which was correlated with the neutropenic phenotype (PMID: 35573728). Homozygous mutations of TCIRG1 are causing autosomal recessive osteopetrosis (ARO), which is characterized by osteopetrosis and secondary hematological and neurological abnormalities. The Genome Aggregation Database (gnomAD) has no data about TCIRG1 R736S and R736C variants accruing in the healthy population. This is in contrast of numerous healthy individuals with a various heterozygous variants throughout the TCIRG1 gene. Aims: We aim to generate in-vitro model of TCIRG1 neutropenia by utilizing patient derived induced pluripotent stem cells (iPSCs) and characterize the hematological abnormalities caused by mutant TCIRG1 expression. We also aim to characterize the incidence of TCIRG1-associated neutropenia and the prevalence of TCIRG1 variants by sharing this new information within the scientific community through identifying more cases/families with this disease. Methods: Medical history, differential WBC counts and whole exome sequencing (WES) was used to identify the genetic basis of neutropenia in the family with R736S mutation. The R736C mutation in the new families also were identified by WES of the index cases. Medical history, blood counts and Sanger sequencing identified their affected relatives. iPSC lines of 4 affected individuals from 2 families harboring TCIRG1 R736S and R736C mutations and healthy volunteer were generated using standard methodology. S732F benign heterozygous TCIRG1 variant was generated by utilizing CRISPR/Cas9 knock-In gene editing using a healthy volunteer iPSC line. iPSCs hematopoietic differentiation was achieved by using STEMdiff Hematopoietic Kit. Resultant CD34+ cells were differentiated towards neutrophils using a published protocol (PMID: 35795780). Cell proliferation, survival and differentiation characteristics were measured by automated cell counter and flow cytometry, cell viability staining and surface markers analysis for granulocytic differentiation. Results: The discovery of these families came through the reputation and work of the Severe Congenital Neutropenia International Registry (SCNIR) and the expanding use of WES to identify the causes of hereditary disorders. With the identification of the index cases, we have identified several affected family members in each family. In all three families the severity of neutropenia is variable and correlates with the incidence of recurrent bacterial infections. Myeloid differentiation of CD34+ cells derived from iPSCs of 4 patients from two families with R736S and R736C mutations revealed maturation, survival and proliferation abnormalities compared to volunteer cells and cell line harboring benign S732F heterozygous TCIRG1 mutation. All patient cells had from 2 to 3-fold drop in cell proliferation and cell viability drop by over 70% for the patients with R736S and up to 90% with R736C mutation compared to the controls. The myeloid differentiation in the patients' cells, measured by flow cytometry and assessed by CD66b+/CD14+ and CD11b+/CD15+ markers was impaired by 38% and 23% respectively for the patients with R736S and 43% and 24% for the patients harboring R736C mutation. Conclusions: The pathogenesis of TCIRG1-associated neutropenia is currently unknown. Carriers of pathogenic variants from these families appear to have neutropenia with variable severity. Our preliminary studies show that patient iPSC derived hematopoietic cells closely recapitulate the neutropenic phenotype. Population based genomic studies; careful family histories and WES will identify new patients with this disorder.