Search Results (74)

Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, continues to be a significant global health issue, especially in Latin America, with increasing international prevalence due to migration. Despite advancements in diagnosis and treatment, it remains a neglected tropical disease characterized by significant morbidity and mortality, mainly influenced by the complex interaction between parasite diversity and host immune responses. Importantly, the remarkable genetic diversity of T. cruzi lineages also contributes to clinical heterogeneity, influencing immune evasion, therapeutic responses, and vaccine feasibility. This review analyzes the impact of immunogenetics on host–parasite interactions in Chagas disease and explores its implications for personalized therapy approaches. Recent research, particularly over the last decade, has indicated that processes including antigenic variation, extracellular vesicle-mediated regulation, and disruption of host signaling pathways facilitate parasite persistence. Host genetic variables significantly influence susceptibility, disease development, and treatment outcomes, including changes in Human Leukocyte Antigen (HLA) genes, cytokine gene polymorphisms, and immunogenetic determinants of cardiac pathology. These findings underscore the potential of immunogenetic markers as tools for prognosis and as targets for personalized therapies. However, there are still considerable research deficiencies. Inadequate comprehension of gene–environment interactions, lack of representation of varied populations, and inconsistencies in study design limit the use of immunogenetic findings in therapeutic settings. At present, the concept of personalized medicine in Chagas disease remains largely aspirational, better understood as a framework for precision public health or stratified interventions guided by host immunogenetic and parasite lineage data. Addressing these issues necessitates comprehensive genomic research, mechanistic investigations of host–parasite interactions, and clinical validation of genetic markers. This study emphasizes the necessity of incorporating immunogenetics into personalized patient management strategies based on existing evidence. This integration has the potential to improve diagnosis, enhance treatment efficacy, and inform preventive interventions, thereby advancing personalized therapy for Chagas disease. Full article

Background/objectives: Psoriatic disease (PsD) encompasses psoriasis (PsO) and psoriatic arthritis (PsA) and is associated with heterogeneous cardiometabolic risk. Integrating immunogenetic markers such as HLA-Cw6 into data-driven analyses may refine phenotyping and uncover clinically meaningful endotypes. We aimed to identify cardiometabolic phenotypes across PsD, integrating HLA-Cw6 and exploring disease-specific heterogeneity and predictors of high-risk profiles. Methods: In a cross-sectional study of 572 PsD patients (401 PsO, 171 PsA), eight demographic and clinical variables, including HLA-Cw6, were entered into k-means clustering (k = 4). Cardiometabolic risk factors were profiled post hoc. Cluster validity was assessed by Gaussian Mixture Models and principal component analysis (PCA). Stratified analyses (k = 3) were conducted separately for PsO and PsA. Predictors of the high-risk phenotype were examined using bootstrap-resampled logistic regression. Results: Four cardiometabolic phenotypes were identified, ranging from younger patients with active PsO and low cardiometabolic burden to a small, high-risk subgroup (~6%) combining older age, universal cardiovascular disease, and a clustering of hypertension, diabetes, and dyslipidemia. Disease-stratified analyses showed that high-risk phenotypes were present in both PsO and PsA. In stratified analyses, HLA-Cw6 showed opposite associations—enriched in high-risk PsO (OR 2.0, 95% CI 1.3–3.1) but depleted in high-risk PsA (OR 0.24, 95% CI 0.11–0.52). Conclusions: Incorporating HLA-Cw6 into clustering identified reproducible cardiometabolic phenotypes with distinct genetic signatures. The inverse HLA-Cw6 risk patterns in PsO and PsA suggest disease-specific patterns that may have differing cardiometabolic implications, which should be tested in longitudinal studies. Full article

Statin exposure has been associated with a broad spectrum of muscle toxicity, ranging from asymptomatic creatine kinase (CK) elevation to immune-mediated necrotizing myopathy (IMNM) with anti-3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) antibodies. The mechanisms underlying these adverse effects are not fully understood, and genetic predisposition may play a role. This observational study evaluated the association of HLA-DRB1*11 and SLCO1B1 rs4149056 variants with statin-induced muscle toxicity. A total of 62 statin-exposed patients treated at a single tertiary center were included and classified as follows: IMNM with anti-HMGCR antibodies (n = 11), non-immune myotoxicity (n = 20), and statin-exposed controls without myopathy (n = 31). The mean age was 66 ± 7.5 years, and 62% were women. The frequency of the HLA-DRB1*11 allele was significantly higher in patients with anti-HMGCR IMNM compared to those with non-immune myotoxicity (81.0% vs. 25.0%; OR = 13.5, 95% CI 1.73–15.3; p < 0.01) and controls (81.0% vs. 17.2%; OR = 21.6, 95% CI 2.87–23.7; p < 0.01). No significant difference was found between the non-immune myotoxicity and control groups. Likewise, the SLCO1B1 rs4149056 variant showed no association with either IMNM or non-immune muscle toxicity. These findings confirm a strong association between the HLA-DRB1*11 allele and anti-HMGCR IMNM. This genetic marker may help to better distinguish immune-mediated from non-immune forms of statin-related myopathy. Full article

Background/Objectives: Human leukocyte antigen B27 (HLA-B27) is a genetic marker strongly associated with various inflammatory rheumatic diseases, particularly those within the spondyloarthritis spectrum. Its presence influences disease onset, clinical severity, and therapeutic strategies. However, comparative data between HLA-B*27-positive and -negative patients, especially in Eastern European populations, remain limited. The study aimed to investigate the clinical, paraclinical, and psychosocial differences between HLA-B*27-positive and -negative individuals diagnosed with rheumatic diseases, in order to better understand the implications of HLA-B27 status on disease expression and patient quality of life. Methods: A cross-sectional, observational study was conducted between June 2023 and December 2024 at the Emergency Clinical Hospital for Children “Sf Ioan” in Galati, Romania, in collaboration with “Dunarea de Jos” University. Fifty adult patients with various rheumatic conditions were enrolled and stratified into HLA-B*27-positive (n = 22) and -negative (n = 28) groups. Data collection included clinical evaluations, laboratory biomarkers (CRP = C-reactive protein; ESR = erythrocyte sedimentation rate), and a structured quality-of-life questionnaire. Statistical analysis was performed using SPSS v27. Results: HLA-B*27-positive patients were significantly younger (mean age 46.00 vs. 55.07 years, p = 0.018) and had higher CRP levels (>1 mg/dL in 53.33% vs. 0%, p = 0.001). Ankylosing spondylitis was more prevalent in this group (22.73% vs. 3.57%, p = 0.039). Magnetic resonance imaging (MRI) was more frequently used (68.18% vs. 39.29%, p = 0.042), indicating greater suspicion of axial involvement. HLA-B27-positive patients also reported higher perceived stress (mean score 2.41 vs. 1.21, p < 0.001). Conclusions: HLA-B*27 positivity is associated with earlier disease onset, increased systemic inflammation, greater axial involvement, and higher psychological stress. These findings emphasise the need for personalised, multidisciplinary care that integrates both medical and psychological support for HLA-B*27-positive patients. Full article

Background: Pancreas and pancreas–kidney transplantation are well-established therapeutic options for patients with type 1 diabetes mellitus (T1DM) and end-stage kidney disease (ESKD), offering the potential to restore endogenous insulin production and kidney function. It improves metabolic control, quality of life, and long-term survival. While surgical techniques and immunosuppressive strategies have advanced considerably, graft rejection and limited long-term graft survival remain significant clinical challenges. Method: To better understand these risks, the genetic and immunological factors that influence transplant outcomes are examined. Beyond traditional human leukocyte antigen (HLA) matching, non-HLA genetic variants such as gene deletions and single-nucleotide polymorphisms (SNPs) have emerged as contributors to alloimmune activation and graft failure. Result: Polymorphisms in cytokine genes, minor histocompatibility antigens, and immune-regulatory pathways have been implicated in transplant outcomes. However, the integration of such genomic data into clinical practice remains limited due to underexplored gene targets, variability in study results, and the lack of large, diverse, and well-characterized patient cohorts. Initiatives like the International Genetics & Translational Research in Transplantation Network (iGeneTRAiN) are addressing these limitations by aggregating genome-wide data from thousands of transplant donors and recipients across multiple centers. These large-scale collaborative efforts aim to identify clinically actionable genetic markers and support the development of personalized immunosuppressive strategies. Conclusions: Overall, genetic testing and genomics hold great promise in advancing precision medicine in pancreas and pancreas–kidney transplantation. Full article

Natural killer (NK) cells play a key role in the innate immune response against viral infections. Their activity is regulated by a balance of activating and inhibitory signals, which are modulated by interactions with HLA class I molecules, including HLA-E. The HLA-B 21M/T dimorphism influences the availability of HLA-B leader peptides that stabilize HLA-E expression and modulate NK cell function via the NKG2A/CD94 receptor. To investigate the association between the HLA-B –21M/T dimorphism and the clinical severity of COVID-19, we analyzed a cohort of hospitalized patients with primary SARS-CoV-2 infection, who were genotyped for the HLA-B –21M/T dimorphism. Clinical data, lymphocyte counts, the neutrophil-to-lymphocyte ratio (NLR), and inflammatory markers were compared across genotypes. Contrary to previous studies suggesting a protective effect of the M/M genotype, we found no significant association between the HLA-B –21M/T dimorphism and COVID-19 severity, lymphocyte parameters, or inflammatory biomarkers. Our findings do not support a role for the HLA-B –21M/T dimorphism in modulating COVID-19 outcomes. These results underscore the complexity of NK cell regulation and highlight the need for integrative studies combining genetic, immunological, and functional data to better understand host factors influencing disease progression. Full article

A large cohort of Romanian children suspected of celiac disease (CD) received comprehensive evaluation through this study regarding serological, genetic, and biochemical markers. This study investigated the relationships between anti-tissue transglutaminase (anti-tTG), anti-endomysium antibodies (EMAs), anti-gliadin deamidated (DGP) antibodies, and HLA genotyping. A strong association was observed between high anti-tTG IgA titers (>100 U/mL) and EMA IgA positivity, with a 95% concordance rate. Furthermore, anti-tTG IgA positive correlated with a significant prevalence of DGP antibodies, suggesting the complementary diagnostic role of DGP antibodies in equivocal cases. Genetic testing for HLA-DQ2/DQ8 alleles validated their association with celiac disease susceptibility, with 50% of the studied patients exhibiting these markers. The research reveals that vitamin D insufficiency affects a large number of children with anti-tTG antibodies, thus requiring both screening and supplementation practices. Furthermore, associations with other autoimmune conditions were explored, including thyroid and diabetes-related autoantibodies. This research demonstrates why CD diagnosis and management require a complete approach that combines serological tests with genetic evaluation and prompt intervention for related health conditions. Full article

Lamotrigine is the drug of choice for the treatment of depressive episodes in bipolar disorder (BD). Despite its generally favorable tolerability profile, lamotrigine use is associated with a risk of Cutaneous Adverse Drug Reactions (cADRs), including Stevens–Johnson Syndrome (SJS) and Lyell’s syndrome, also known as toxic epidermal necrolysis (TEN). Genetic markers HLA and, in particular, HLA-B 15:02 and HLA-A 31:01 are crucial in predicting individuals’ susceptibility to developing the symptoms. The symptoms are triggered by type IV hypersensitivity developing because of CTL and NK cell activation, leading to keratinocyte apoptosis, epidermal necrosis and skin detachment. The exact pharmacotherapy that should be widely utilized in treating affected patients has not yet been established. New therapies including JAK inhibitors or cyclosporine show potential in improving outcomes by reducing mortality and enhancing the period of recovery. Key factors in preventing cADRs may include adequate patient observation, gradual titration of the patient’s dose, and reduction of risk factors through screening for HLA polymorphisms. When the initial symptoms of cADR are identified, it is imperative to make an immediate decision to discontinue treatment, as this can significantly reduce the risk of progression to SJS/TEN and systemic complications. The purpose of this review is to identify a significant correlation between lamotrigine use in BD and the occurrence of SJS by showing the risk factors, neuropharmacological mechanisms, immune response and correctness of pharmacotherapy. Full article

Background: Although clinical studies have indicated a possible association between dyslipidemia and osteoporosis, the underlying genetic basis and mechanistic pathways remain insufficiently defined. Most prior research has concentrated on conventional lipid markers, which are prone to confounding and limit causal inference. Exploring lipidomic profiles offers a more comprehensive view of lipid metabolism and may reveal novel genetic links beyond traditional lipid traits. Additionally, alterations in immune cell function, often triggered by metabolic disturbances, may contribute to osteoporosis development; however, the potential mediating role of immune cells in the lipid–bone axis has not been systematically investigated. Methods: A total of 179 lipid species across 13 lipid classes were analyzed in 7174 Finnish individuals from the GeneRISK cohort. Genome-Wide Association Study (GWAS) summary statistics for osteoporosis and 731 immune cell immunophenotypes were sourced from the GWAS Catalog. A two-step, two-sample Mendelian randomization analysis, using inverse variance weighting (IVW), was conducted to explore the potential causal effects of lipids on osteoporosis and the mediating role of immune cells in the relationship between lipids and osteoporosis. Results: Mendelian randomization analysis indicated that triacylglycerol levels of 48:0 were possibly associated with an increased risk of osteoporosis (IVW: odds ratio [OR] 1.1320, 95% CI 1.0401–1.2321; p = 0.004), while triacylglycerol levels of 48:3 appeared to be associated with a reduced risk of osteoporosis (IVW: OR 0.9053, 95% CI 0.8364–0.9800; p = 0.014). Two statistically significant mediating effects were identified: First, IgD− CD38dim %B cells appeared to partially negatively mediate the association between triacylglycerol levels of 48:3 and osteoporosis, with a negative mediating effect of −0.00669 (95% CI: −0.0214, 0.00805), which accounted for 6.73% of the total effect. That is, the protective effect of triacylglycerol levels of 48:3 against osteoporosis was attenuated by IgD− CD38dim %B cells. Second, HLA DR++ monocytes% leukocytes also partially negatively mediated this relationship, with a mediating effect of −0.023 (95% CI: −0.0434, −0.00266), accounting for 23.2% of the total effect. This indicates that other immune cells, HLA DR++ monocytes %leukocytes, resisted the protective effect of triacylglycerol levels of 48:3 against osteoporosis, with a weakening effect stronger than that of IgD− CD38dim %B cells. Conclusions: Our findings contribute to the growing understanding of the potential causal relationships and shared pathogenic mechanisms between dyslipidemia and osteoporosis. The results suggest that the potential genetic effects of plasma lipid metabolites on osteoporosis may be partially down-regulated by specific kinds of immune cells. Full article

Background/Objectives: Diabetic kidney disease (DKD) is a common diabetic complication, driven by a multifactorial pathogenesis that includes various genetic components. However, the precise causative genes and their underlying biological pathways remain poorly understood. Methods: We performed a cross-tissue transcriptome-wide association study (TWAS) of DKD using expression quantitative trait loci (eQTL) data from 49 tissues in the Genotype—Tissue Expression (GTEx) version 8 (v8) resource. Five complementary analytical frameworks—sparse canonical correlation analysis (sCCA), functional summary-based imputation (FUSION), fine-mapping of causal gene sets (FOCUS), summary-data-based Mendelian randomization (SMR), and multi-marker analysis of genomic annotation (MAGMA)—were integrated to nominate candidate genes. Causal inference was refined using Mendelian randomization (MR), and biological significance was evaluated through pathway enrichment, protein interaction networks, and druggability profiling. Results: We identified 23 candidate genes associated with DKD risk, of which 13 were supported by MR analysis. Among these, 10 represent previously unreported susceptibility genes. Notably, four genes—HLA-DRB1, HLA-DRB5, NOTCH4, and CYP21A2—encode potentially druggable proteins, with HLA-DRB5 and CYP21A2 both qualifying as novel susceptibility genes and therapeutic targets. These genes converge on immune modulation, steroid biosynthesis, DNA repair, and transcriptional regulation—processes central to DKD pathogenesis. Conclusions: Our study represents the first systematic cross-tissue TWAS of DKD, revealing a prioritized set of genetically and functionally supported susceptibility genes. The identification of druggable targets among these genes provides critical insight into the mechanistic underpinnings of DKD and highlights their potential for future therapeutic development. These findings enhance our understanding of DKD pathophysiology and offer a foundation for precision medicine strategies in nephrology. Full article

Background and Objectives: Spondylarthritis is a complex group of inflammatory diseases closely associated with the HLA-B27 antigen. However, the role of non-HLA-B27 alleles in the disease’s pathogenesis has gained significant scholarly attention in recent years. Case presentation: This case study presents a 49-year-old male with a history of progressive inflammatory back pain, characterized by morning stiffness and restricted spinal mobility developed over several years. Initially presenting with non-specific symptoms, the patient eventually experienced persistent axial pain and deteriorating functional limitations, which required further evaluation. Radiographic imaging supported the diagnosis of ankylosing spondylitis (AS) by identifying bilateral sacroiliitis. HLA genotyping revealed a negative result for HLA-B27 but positive results for HLA-B13 and HLA-B37. This finding serves as a foundation for exploring alternative genetic factors contributing to spondylarthritis (SpA). HLA-B13 and HLA-B37 exhibit structural and functional similarities to HLA-B27, particularly in their peptide-binding grooves. This resemblance may lead to overlapping peptide repertoires and increased T cell cross-reactivity. Moreover, these alleles belong to overlapping cross-reactive groups (CREGs) and share the Bw4 epitope. This suggests that they may contribute to disease pathogenesis via similar mechanisms, such as molecular mimicry and the dysregulation of natural killer (NK) cell interactions, as observed in HLA-B27. Conclusions: This case emphasizes the necessity of expanding diagnostic criteria to incorporate non-HLA-B27 markers, particularly for patients who are HLA-B27-negative. Enhancing our understanding of the roles of alternative genetic markers can improve diagnostic accuracy, enable personalized treatment approaches, and enhance outcomes for the diverse SpA patient population. Full article

Epilepsy is a prevalent neurological disorder that affects millions worldwide, with a significant portion of individuals experiencing drug-resistant forms of the condition. In Latin America, the challenge of identifying the underlying causes of multidrug-resistant epilepsy (MDRE) is particularly pressing. (1) Background: This systematic review aims to highlight the critical importance of understanding the etiology of MDRE in Latin America. (2) Methods: A systematic review of Medline (PubMed), Scopus, and Web of Science was conducted following the PRISMA methodology; articles were selected if they included information on the etiology of MDRE in Latin-American participants, and the NHLBI tool was used to assess bias. (3) Results: A total of 37 published articles were finally included in the review. The most frequently documented cause of drug-resistant epilepsy was structural, affecting 725 patients, with hippocampal atrophy and sclerosis predominantly involving both the right and left lobes. The second most common cause was genetic, identified in 362 individuals who exhibited polymorphisms in genes such as ABCB1, CYP2C9, SCN1A, SLC6A4, and MDR-1, among others. The third most frequent cause was metabolic, and the fourth was inflammatory, affecting 258 individuals, which was associated with various inflammatory markers, including IL-1β, IL-6, CD8+, CD-25, and HLA-DR. Finally, infectious causes were also reported. (4) Conclusions: Structural causes are the leading etiology of MDRE in Latin America, followed by genetic, metabolic, inflammatory, and infectious origins. The regional pattern contrasts with findings from Europe and Asia, highlighting the influence of socioeconomic, environmental, and population-specific genetic factors. Our findings underscore the urgent need for regionally tailored research and interventions, particularly in understudied areas such as infectious causes and neuroinflammation. Full article

Background: Behçet’s Disease (BD) is a complex vasculitis affecting multiple organ systems, with Neuro-Behçet’s Disease (NBD) representing a rare yet severe manifestation. Data on NBD are limited, particularly in Middle Eastern populations. Methods: This retrospective observational study, spanning from 2000 to 2021, involved 262 BD patients at a tertiary medical center in Lebanon. NBD was diagnosed based on International Consensus Recommendation diagnostic criteria. Clinical data, including demographics, manifestations, inflammatory blood markers, genetics, and treatments, were collected. The modified Rankin Scale (mRS) was used to assess disease severity. Results: Among the cohort, 27 (10.3%) had NBD, with headaches, weakness, and dizziness as the most common presenting symptoms. The prevalence of NBD was similar across genders, which differs from some regional studies. HLA-B51 positivity was found in 50 out of 60 (83.3%) tested BD patients. Parenchymal NBD cases exhibited greater disease severity than non-parenchymal cases, with female patients experiencing a more severe course compared to males. Elevated inflammatory markers (CRP and ESR) were more common in patients with severe NBD. Corticosteroids and colchicine were the most commonly used therapies overall, while patients with better disease severity were more frequently prescribed methotrexate, mycophenolate, cyclophosphamide, adalimumab, and rituximab. An analysis of disease progression showed that at presentation, 57.1% (n = 12) of NBD patients had mild to moderate disability, which increased to 76.2% (n = 16) at the last follow-up, including 10 patients who showed an improvement in their mRS score. Conclusions: This study provides valuable insights into the prevalence and clinical characteristics of NBD in a Middle Eastern population. These findings enhance our understanding of NBD in the Middle East, highlighting the need for further research to improve diagnosis and management. Full article

Background: Acute myeloid leukemia (AML) complicated by disseminated intravascular coagulation (DIC) poses major diagnostic and therapeutic challenges. While DIC is well documented in acute promyelocytic leukemia, its manifestations in non-APL AML remain underexplored, necessitating precise diagnostic strategies for effective management. Methods: AML patients with overt DIC were analyzed, including morphological, immunophenotypic, cytogenetic, and genetic evaluations. DIC was diagnosed using the ISTH scoring system, and AML subtypes were classified following WHO criteria. Results: Three diagnostic patterns were identified. (1) Acute promyelocytic leukemia: Leukemia characterized by PML::RARa rearrangements, FLT3 co-mutations, and frequent Auer rods and faggot bundles. Immunocytological analysis showed CD34 and HLA-DR negativity. (2) AML with FLT3 and/or NPM1 mutations: A high prevalence of cup-like blasts was found in 70% of cases. FLT3 mutations, often co-occurring with NPM1, dominated, while karyotypes were typically normal. Immunophenotyping revealed strong myeloid marker expression (MPO+, CD13+, and CD33+), with occasional CD34 negativity. (3) AML with monocytic differentiation: Leukemia defined by monoblastic/promonocytic morphology, DNMT3A mutations, and complex karyotypes or 11q23 rearrangements. Immunophenotyping demonstrated a dominance of monocytic markers (CD4+, CD14+, CD15+, and CD64+). Two patients presented unique profiles with no alignment to these patterns. Conclusions: This study highlights distinct hematopathological patterns of AML with overt DIC, providing a framework for early and precise diagnosis. Recognizing these patterns is critical for tailoring diagnostic and therapeutic approaches to improve outcomes in this high-risk population. Full article

Autism spectrum disorder (ASD) is an early-onset neurodevelopmental condition that now impacts 1 in 36 children in the United States and is characterized by deficits in social communication, repetitive behaviors, and restricted interests. Children with ASD also frequently experience co-morbidities including anxiety and ADHD, and up to 80% experience gastrointestinal (GI) symptoms such as constipation, diarrhea, and/or abdominal pain. Systemic immune activation and dysregulation, including increased pro-inflammatory cytokines, are frequently observed in ASD. Evidence has shown that the innate immune system may be impacted in ASD, as altered monocyte gene expression profiles and cytokine responses to pattern recognition ligands have been observed compared to typically developing (TD) children. In humans, circulating monocytes are often categorized into three subpopulations—classical, transitional (or “intermediate”), and nonclassical monocytes, which can vary in functions, including archetypal inflammatory and/or reparative functions, as well as their effector locations. The potential for monocytes to contribute to immune dysregulation in ASD and its comorbidities has so far not been extensively studied. This study aims to determine whether these monocyte subsets differ in frequency in children with ASD and if the presence of GI symptoms alters subset distribution, as has been seen for T cell subsets. Whole blood from ASD children with (ASD⁺GI⁺) and without gastrointestinal symptoms (ASD⁺GI⁻) and their TD counterparts was collected from children enrolled in the Childhood Autism Risk from Genetics and Environment (CHARGE) study. Peripheral blood mononuclear cells were isolated and stained for commonly used subset identifiers CD14 and CD16 as well as activation state markers CCR2, HLA-DR, PD-1, and PD-L1 for flow cytometry analysis. We identified changes in monocyte subpopulations and their expression of surface markers in children with ASD compared to TD children. These differences in ASD appear to be dependent on the presence or absence of GI symptoms. We found that the ASD⁺GI⁺ group have a different monocyte composition, evident in their classical, transitional, and nonclassical populations, compared to the ASD⁺GI⁻ and TD groups. Both the ASD⁺GI⁺ and ASD⁺GI⁻ groups exhibited greater frequencies of classical monocytes compared to the TD group. However, the ASD⁺GI⁺ group demonstrated lower frequencies of transitional and nonclassical monocytes than their ASD⁺GI⁻ and TD counterparts. CCR2⁺ classical monocyte frequencies were highest in the ASD⁺GI⁻ group. HLA-DR⁺ classical, transitional, and nonclassical monocytes were statistically comparable between groups, however, HLA-DR⁻ nonclassical monocyte frequencies were lower in both ASD groups compared to TD. The frequency of classical monocytes displaying exhaustion markers PD-1 and PD-L1 were increased in the ASD⁺GI⁺ group compared to ASD⁺GI⁻ and TD, suggesting potentially impaired ability for clearance of foreign pathogens or debris, typically associated with worsened inflammation. Taken together, the findings of differential proportions of the monocyte subpopulations and altered surface markers may explain some of the characteristics of immune dysregulation, such as in the gastrointestinal tract, observed in ASD. Full article