Reduction in mucosal-associated invariant T cells (MAIT) in APECED patients is associated with elevated serum IFN-γ concentration.

Mucosal-associated invariant T cells (MAIT) are innate-like lymphocytes enriched in mucosal organs where they contribute to antimicrobial defense. APECED is an inborn error of immunity characterized by immune dysregulation and chronic mucocutaneous candidiasis. Reduction in the frequency of circulating MAITs has been reported in many inborn errors of immunity, but only in a few of them, the functional competence of MAITs has been assessed. Here, we show in a cohort of 24 patients with APECED, that the proportion of circulating MAITs was reduced compared with healthy age and sex-matched controls (1.1% vs. 2.6% of CD3+ T cells; p < 0.001) and the MAIT cell immunophenotype was more activated. Functionally the IFN-γ secretion of patient MAITs after stimulation was comparable to healthy controls. We observed in the patients elevated serum IFN-γ (46.0 vs. 21.1 pg/mL; p = 0.01) and IL-18 (42.6 vs. 13.7 pg/mL; p < 0.001) concentrations. Lower MAIT proportion did not associate with the levels of neutralizing anti-IL-22 or anti-IL-12/23 antibodies but had a clear negative correlation with serum concentrations of IFN-γ, IL-18, and protein C-reactive protein. Our data suggest that reduction of circulating MAITs in patients with APECED correlates with chronic type 1 inflammation but the remaining MAITs are functionally competent.

Increased type 1 inflammation in gynecologic cervicovaginal samples in patients with APS-1.

BACKGROUND: Inborn errors of immunity offer important insights into mucosal immunity. In autoimmune polyendocrine syndrome type-1 (APS-1), chronic mucocutaneous candidiasis has been ascribed to neutralizing IL-17 autoantibodies. Recent evidence implicates excessive T-cell IFN-γ secretion and ensuing epithelial barrier disruption in predisposition to candidiasis, but these results remain to be replicated. Whether IL-17 paucity, increased type I inflammation, or their combination underlies susceptibility to chronic mucocutaneus candidiasis in APS-1 is debated. OBJECTIVE: Our aim was to characterize the immunologic features in the cervicovaginal mucosa of females with APS-1. METHODS: Vaginal fluid was collected with a flocked swab from 17 females with APS-1 and 18 controls, and cytokine composition was analyzed using Luminex (Luminex Corporation, Austin, Tex). Cervical cell samples were obtained with a cervix brush from 6 patients and 6 healthy controls and subjected to transcriptome analysis. RESULTS: The vaginal fluid samples from patients with APS-1 had IFN-γ concentrations comparable to those of the controls (2.6 vs 2.4 pg/mL) but high concentrations of the TH1 chemokines CXCL9 and CXCL10 (1094 vs 110 pg/mL [P < .001] and 4033 vs 273 pg/mL [P = .001], respectively), whereas the IL-17 levels in the samples from the 2 groups were comparable (28 vs 8.8 pg/mL). RNA sequencing of the cervical cells revealed upregulation of pathways related to mucosal inflammation and cell death in the patients with APS-1. CONCLUSION: Excessive TH1 cell response appears to underlie disruption of the mucosal immune responses in the genital tract of patients with APS-1 and may contribute to susceptibility to candidiasis in the genital tract as well.

Dysregulated germinal center reaction with expanded T follicular helper cells in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy lymph nodes.

BACKGROUND: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED, also called APS-1) is an inborn error of immunity with clear signs of B-cell autoimmunity such as neutralizing anti-IFN antibodies. In APECED, mutations in the AIRE gene impair thymic negative selection of T cells. The resulting T-cell alterations may then cause dysregulation of B-cell responses. However, no analysis of interactions of T and B cells in the germinal centers (GCs) in patients' secondary lymphatic tissues has been reported. OBJECTIVE: This study examined the relationship between B cells and follicular T helper cells (TfH) in peripheral blood and lymph node (LN) GCs in patients with APECED. METHODS: Immunophenotyping of peripheral blood B cells and TfH was performed for 24 patients with APECED. Highly multiplexed fluorescent immunohistochemical staining was performed on 7 LN biopsy samples from the patients to study spatial interactions of lymphocytes in the GCs at the single-cell level. RESULTS: The patients' peripheral B-cell phenotype revealed skewing toward a mature B-cell phenotype with marked loss of transitional and naive B cells. The frequency of circulating TfH cells was diminished in the patients, while in the LNs the TfH population was expanded. In LNs the overall frequency of Treg cells and interactions of Treg cells with nonfollicular T cells were reduced, suggesting that aberrant Treg cell function might fail to restrain TfH differentiation. CONCLUSIONS: GC reactions are disrupted in APECED as a result of defective T-cell control.

Neurological Diseases and Prevalence of Antineuronal Antibodies in Patients with Autoimmune Polyendocrine Syndrome Type 1 - A National Cohort Study.

Autoimmune polyendocrine syndrome type 1 (APS-1) is a rare monogenic disease caused by mutations in the autoimmune regulator gene. Although the disease-associated autoantibodies mostly target endocrine organs, autoantibodies from patients with APS-1 bind also to rat brain structures. The patients often have GAD65-antibodies, that can cause autoimmune encephalitis. However, neurological manifestations of APS-1 have not been systematically explored. We conducted a retrospective chart review on 44 Finnish patients with APS-1 (median age 38 years, 61% females) and collected all their neurological diagnoses. To assess the prevalence of serum antineuronal antibodies in APS-1, serum samples of 24 patients (median age 36 years, 63% females) were analyzed using a fixed cell-based assay. Of the 44 APS-1 patients, 10 (23%) had also received a diagnosis of a neurological disease. Of these neurological comorbidities, migraine (n = 7; 16%), central nervous system infections (n = 3; 7%), and epilepsy (n = 2; 5%) were the most prevalent. Other diagnoses recorded for single patients were axonal sensorimotor polyneuropathy, essential tremor, idiopathic intracranial hypertension, ischemic stroke, and trigeminal neuralgia. Serum antineuronal antibodies were detected in 42% of patients tested (10/24, 50% females, median age 42 years), GAD65 antibodies being the most common finding. Antibodies against glycine and aquaporin 4 were found in low titers. In four patients, relatively high titers of GAD65 antibodies without coexisting type 1 diabetes were found, but none presented with GAD65-encephalitis. Our study suggests an association between APS-1 and neurological disorders, the mechanisms of which are to be further investigated.

PLS3 Mutations in X-Linked Osteoporosis: Clinical and Genetic Features in Five New Families.

Childhood-onset osteoporosis is a rare but clinically significant condition. Studies have shown pathogenic variants in more than 20 different genes as causative for childhood-onset primary osteoporosis. The X-chromosomal PLS3, encoding Plastin-3, is one of the more recently identified genes. In this study, we describe five new families from four different European countries with PLS3-related skeletal fragility. The index cases were all hemizygous males presenting with long bone and vertebral body compression fractures. All patients had low lumbar spine bone mineral density (BMD). The age at the first clinical fracture ranged from 1.5 to 13 years old. Three of the identified PLS3 variants were stop-gain variants and two were deletions involving either a part or all exons of the gene. In four families the variant was inherited from the mother. All heterozygous women reported here had normal BMD and no bone fractures. Four patients received bisphosphonate treatment with good results, showing a lumbar spine BMD increment and vertebral body reshaping after 10 months to 2 years of treatment. Our findings expand the genetic spectrum of PLS3-related osteoporosis. Our report also shows that early treatment with bisphosphonates may influence the disease course and reduce the progression of osteoporosis, highlighting the importance of early diagnosis for prompt intervention and appropriate genetic counseling.

Low-grade inflammation from prenatal period to age 6-8 years in a Vitamin D trial.

BACKGROUND: Low-grade systemic inflammation measured as high sensitivity C-reactive protein (hs-CRP) has been associated with non-communicable disease risk. We assessed whether prenatal inflammation and early-childhood vitamin D are associated with inflammation until age 6-8. METHODS: We analyzed blood hs-CRP and 25-hydroxy vitamin D [25(OH)D] in pregnancy, at birth from umbilical cord blood (UCB), from offspring at ages 1, 2, and 6-8 years in the Vitamin D Intervention in Infants (VIDI) study. VIDI was a randomized-controlled trial of vitamin D supplementation of 10 µg/day or 30 µg/day from age 2 weeks until 2 years in 975 infants recruited in 2013-14, with follow-up at age 6-8 in 2019-21 (n = 283). RESULTS: Pregnancy hs-CRP was associated with UCB hs-CRP (r = 0.18, p < 0.001) but not independently with childhood hs-CRP (Estimate [95% CI] 0.04 [<-0.00, 0.09]). Higher UCB hs-CRP was associated independently with higher hs-CRP until 6-8 years (0.20 [0.12, 0.29]). Infant vitamin D dose had no effect on longitudinal hs-CRP (6-8 years, 0.11 [-0.04, 0.25]). Childhood 25(OH)D were associated positively with hs-CRP until age 6-8 (0.01 [>0.00, 0.01]). CONCLUSION: Our results indicate that in children, inflammation, assessed by hs-CRP, persists from birth until 6-8 years. We observed positive associations between 25(OH)D and hs-CRP in vitamin D-sufficient children. IMPACT: High sensitivity C-reactive protein (hs-CRP) concentrations tract from birth to age 8 years Our novel finding suggests a long-lasting pro-inflammatory phenotype in the child Higher vitamin D concentration - but not dose - is associated with higher childhood hs-CRP Chronic disease risk related to inflammation may in part originate from the prenatal period or early childhood Further studies are needed to investigate the effects of inflammation on long-term clinical health outcomes.

Bisphosphonate treatment for skeletal complications in paediatric cancer-Experience from a single tertiary centre.

AIMS: The aim was to analyse the use and safety of bisphosphonate treatment for metabolic bone complications in paediatric cancer patients. METHODS: We retrospectively describe our experience with bisphosphonate treatment in 25 childhood cancer patients (aged <18 years) in a single tertiary hospital between 1999 and 2020. RESULTS: The most common primary diagnosis was acute lymphoblastic leukaemia (n = 16) and Hodgkin lymphoma (n = 3). Eleven patients (44%) had received allogeneic stem cell transplantation and two patients autologous stem cell transplantation. Sixteen patients (64%) had been treated with radiotherapy, either total-body (n = 11) or local (n = 5). The main indication for bisphosphonates was osteoporosis with vertebral compression fractures in 13/25, osteonecrosis in 6/25 and hypercalcaemia in 2/25. The bisphosphonate treatment was started on average 13 (range 0-76) months after the diagnosis of the bone complication. Bisphosphonate treatment lasted between weeks (hypercalcaemia) to 5 years (severe osteoporosis). Mild, non-symptomatic hypophosphatemia (n = 8), hypocalcaemia (n = 6) and moderate, transient pain (n = 6) were the most common adverse effects. No severe side effects were observed even when bisphosphonates were administered concomitantly with chemotherapy. Bone mineral density significantly improved with the bisphosphonate treatment (mean lumbar spine Z-score -1.17 vs. -0.07, p < 0.001). CONCLUSION: Bisphosphonate treatment was well tolerated in this paediatric patient cohort.

A gene-centric approach to biomarker discovery identifies transglutaminase 1 as an epidermal autoantigen.

Autoantigen discovery is a critical challenge for the understanding and diagnosis of autoimmune diseases. While autoantibody markers in current clinical use have been identified through studies focused on individual disorders, we postulated that a reverse approach starting with a putative autoantigen to explore multiple disorders might hold promise. We here targeted the epidermal protein transglutaminase 1 (TGM1) as a member of a protein family prone to autoimmune attack. By screening sera from patients with various acquired skin disorders, we identified seropositive subjects with the blistering mucocutaneous disease paraneoplastic pemphigus. Validation in further subjects confirmed TGM1 autoantibodies as a 55% sensitive and 100% specific marker for paraneoplastic pemphigus. This gene-centric approach leverages the wealth of data available for human genes and may prove generally applicable for biomarker discovery in autoimmune diseases.

Bone Tissue Evaluation Indicates Abnormal Mineralization in Patients with Autoimmune Polyendocrine Syndrome Type I: Report on Three Cases.

Autoimmune polyendocrine syndrome type-1 (APS1) is characterized by autoimmune manifestations affecting different organs from early childhood on. Immunological abnormalities, the resulting endocrinopathies, and their treatments may compromise bone health. For the first time in APS1, we analyzed transiliac bone biopsy samples by bone histomorphometry and quantitative backscattered electron imaging in three adult patients (female P1, 38 years; male P2, 47 years; male P3, 25 years). All had biallelic mutations in the autoimmune regulator gene and in addition to endocrinopathies, also significant bone fragility. Histomorphometry showed bone volume in the lower normal range for P1 (BV/TV, - 0.98 SD) and P3 (- 1.34 SD), mainly due to reduced trabecular thickness (TbTh, - 3.63 and - 2.87 SD). In P1, osteoid surface was low (OS/BS, - 0.96 SD); active osteoblasts and double labeling were seen only on cortical bone. P3 showed a largely increased bone turnover rate (BFR/BV, + 4.53 SD) and increased mineralization lag time (Mlt, + 3.40 SD). Increased osteoid surface (OS/BS, + 2.03 and + 4.71 SD for P2 and P3) together with a large proportion of lowly mineralized bone area (Trab CaLow, + 2.22 and + 9.81 SD for P2 and P3) and focal mineralization defects were consistent with abnormal mineralization. In all patients, the density and area of osteocyte lacunae in cortical and trabecular bone were similar to healthy adults. The bone tissue characteristics were variable and included decreased trabecular thickness, increased amount of osteoid, and abnormal mineralization which are likely to contribute to bone fragility in patients with APS1.

Nosology of genetic skeletal disorders: 2023 revision.

The "Nosology of genetic skeletal disorders" has undergone its 11th revision and now contains 771 entries associated with 552 genes reflecting advances in molecular delineation of new disorders thanks to advances in DNA sequencing technology. The most significant change as compared to previous versions is the adoption of the dyadic naming system, systematically associating a phenotypic entity with the gene it arises from. We consider this a significant step forward as dyadic naming is more informative and less prone to errors than the traditional use of list numberings and eponyms. Despite the adoption of dyadic naming, efforts have been made to maintain strong ties to the MIM catalog and its historical data. As with the previous versions, the list of disorders and genes in the Nosology may be useful in considering the differential diagnosis in the clinic, directing bioinformatic analysis of next-generation sequencing results, and providing a basis for novel advances in biology and medicine.