A homozygous loss-of-function C1S mutation is associated with Kikuchi-Fujimoto disease.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a self-limited inflammatory disease of unknown pathogenesis. Familial cases have been described and defects in classical complement components C1q and C4 have been identified in some patients. MATERIAL AND METHODS: We describe genetic and immune investigations of a 16 years old Omani male, a product of consanguineous marriage, who presented with typical clinical and histological features of KFD. RESULTS: We identified a novel homozygous single base deletion in C1S (c.330del; p. Phe110LeufsTer23) resulting in a defect in the classical complement pathway. The patient was negative for all serological markers of SLE. In contrast, two female siblings (also homozygous for the C1S mutation), one has autoimmune thyroid disease (Hashimoto thyroiditis) and a positive ANA and the other sibling has serology consistent with SLE. CONCLUSION: We report the first association between C1s deficiency and KFD.

Short and long-term immune changes in different severity groups of COVID-19 disease.

BACKGROUND: There are limited data on short- versus long-term changes in adaptive immune response across different COVID-19 disease severity groups. METHODS: A multicenter prospective study of 140 adult patients with COVID-19 (a total of 325 samples) were analyzed for inflammatory markers and lymphocyte subsets at presentation, week 2, and week 24. RESULTS: Inflammatory markers at presentation were higher in the critical/severe than in moderate and mild groups. A predominance of memory B cell response in the mild and moderate group was noted by week 2. In contrast, the immune system in the severe/critical group was dysfunctional, with expansion of exhausted CD8+ T cells and atypical memory B cells. By 24 weeks, there was a possible trend of normalization. CONCLUSION: There was substantial difference in the degree of inflammation and distribution of different B and T cell subsets in the different disease severity groups. Despite the initial dysfunctional immune response in the severe/critical group, a comparable memory B and CD8+ T cell responses to the mild group was achieved at 24 weeks.

Prevalence of Coeliac Disease in Omani Adults with Iron Deficiency Anaemia of Unknown Cause: Case-finding study.

Objectives: This study aimed to estimate the serological prevalence of coeliac disease in patients with iron deficiency anaemia (IDA) of unknown cause at a primary healthcare facility in Oman. Methods: This prospective case-finding study was conducted at the primary care clinics in Sultan Qaboos University Hospital, Muscat, Oman from September 2018 to June 2020. Patients aged 18 to 55 years, with a haemoglobin (Hb) level <11.5 g/dL for males and <11.0 g/dL for females and a ferritin level <30 ng/mL for males and <13 ng/mL for females, were included in the study. Blood samples were obtained for initial serological screening using serum immunoglobulin (Ig)A level; those samples with normal levels of IgA, IgA anti-tissue transglutaminase antibody (tTG) and IgA anti-deamidated gliadin peptide (DGP) were determined. Positive IgA-tTG test was confirmed using IgA-endomysial antibodies. Patients with low IgA levels were tested using IgG-tTG and IgG-DGP. Results: A total of 104 patients participated in this study. Eight patients (7.7%) were found to have a positive serological screening result for coeliac disease; of these patients, three (37.5%) had a positive IgA-tTG result. Two of those three (66.7%) had a positive IgA-endomysial antibody. The IgA-DGP result was positive in seven (6.7%) of the 104 patients. Out of those seven patients, two also had a positive IgA tTG. Conclusion: Coeliac disease is not a rare disorder. There is a need to increase awareness among healthcare professionals about coeliac disease and its non-classical manifestations such as IDA.

Immune Dysregulation in Monogenic Inborn Errors of Immunity in Oman: Over A Decade of Experience From a Single Tertiary Center.

Background: Inborn errors of immunity (IEIs) are being recognized as an important cause of morbidity and mortality in communities with a high frequency of consanguinity, such as Oman, and thus recessively inherited conditions. Various monogenic causes of IEI have been recently discovered; however, the disease phenotype may be variable and does not always include infection at presentation, leading to a delay in diagnosis and a poor outcome. It is now well recognized that immune dysregulation manifestations are observed in a significant proportion of patients with IEI and occasionally precede infection. Methods: Here, we retrospectively report the epidemiological, clinical, immunological, and molecular findings and outcomes from 239 patients with IEI who were diagnosed and managed at the Royal Hospital, Oman, from January 2010 to October 2021. Results: The estimated annual cumulative mean incidence of IEI was 25.5 per 100,000 Omani live births with a total prevalence of 15.5 per 100,000 Omani population. Both the high incidence and prevalence are attributed to the high rate of consanguinity (78.2%). Defects affecting cellular and humoral immunity including severe combined immunodeficiency (SCID), combined immunodeficiency (CID), and CID with syndromic features were the predominant defects in IEI (36%). Immune dysregulation was a prominent manifestation and occurred in approximately a third of all patients with IEI (32%), with a mean age of onset of 81 months and a mean diagnostic delay of 50.8 months. The largest percentage of patients who showed such clinical signs were in the category of diseases of immune dysregulation (41%), followed by predominantly antibody deficiency (18%). The overall mortality rate in our cohort was 25.1%, with higher death rates seen in CID including SCID and diseases of immune dysregulation. Conclusion: Immune dysregulation is a frequent manifestation of Omani patients with IEI. Early detection through raising awareness of signs of IEI including those of immune dysregulation and implementation of newborn screening programs will result in early intervention and improved overall outcome.

Proteomics: Concepts and applications in human medicine.

Proteomics is the complete evaluation of the function and structure of proteins to understand an organism's nature. Mass spectrometry is an essential tool that is used for profiling proteins in the cell. However, biomarker discovery remains the major challenge of proteomics because of their complexity and dynamicity. Therefore, combining the proteomics approach with genomics and bioinformatics will provide an understanding of the information of biological systems and their disease alteration. However, most studies have investigated a small part of the proteins in the blood. This review highlights the types of proteomics, the available proteomic techniques, and their applications in different research fields.

Immunological predictors of disease severity in patients with COVID-19.

BACKGROUND: Identifying the immune cells involved in coronavirus disease 2019 (COVID-19) disease progression and the predictors of poor outcomes is important to manage patients adequately. METHODS: This prospective observational cohort study enrolled 48 patients with COVID-19 hospitalized in a tertiary hospital in Oman and 53 non-hospitalized patients with confirmed mild COVID-19. RESULTS: Hospitalized patients were older (58 years vs 36 years, P < 0.001) and had more comorbid conditions such as diabetes (65% vs 21% P < 0.001). Hospitalized patients had significantly higher inflammatory markers (P < 0.001): C-reactive protein (114 vs 4 mg/l), interleukin 6 (IL-6) (33 vs 3.71 pg/ml), lactate dehydrogenase (417 vs 214 U/l), ferritin (760 vs 196 ng/ml), fibrinogen (6 vs 3 g/l), D-dimer (1.0 vs 0.3 µg/ml), disseminated intravascular coagulopathy score (2 vs 0), and neutrophil/lymphocyte ratio (4 vs 1.1) (P < 0.001). On multivariate regression analysis, statistically significant independent early predictors of intensive care unit admission or death were higher levels of IL-6 (odds ratio 1.03, P = 0.03), frequency of large inflammatory monocytes (CD14+CD16+) (odds ratio 1.117, P = 0.010), and frequency of circulating naïve CD4+ T cells (CD27+CD28+CD45RA+CCR7+) (odds ratio 0.476, P = 0.03). CONCLUSION: IL-6, the frequency of large inflammatory monocytes, and the frequency of circulating naïve CD4 T cells can be used as independent immunological predictors of poor outcomes in COVID-19 patients to prioritize critical care and resources.

Malformin-A1 (MA1) Sensitizes Chemoresistant Ovarian Cancer Cells to Cisplatin-Induced Apoptosis.

High-grade epithelial ovarian cancer is a fatal disease in women frequently associated with drug resistance and poor outcomes. We previously demonstrated that a marine-derived compound MalforminA1 (MA1) was cytotoxic for the breast cancer cell line MCF-7. In this study, we aimed to examine the effect of MA1 on human ovarian cancer cells. The potential cytotoxicity of MA1was tested on cisplatin-sensitive (A2780S) and cisplatin-resistant (A2780CP) ovarian cancer cell lines using AlamarBlue assay, Hoechst dye, flow cytometry, Western blot, and RT-qPCR. MA1 had higher cytotoxic activity on A2780S (IC50 = 0.23 µM) and A2780CP (IC50 = 0.34 µM) cell lines when compared to cisplatin (IC50 = 31.4 µM and 76.9 µM, respectively). Flow cytometry analysis confirmed the cytotoxic effect of MA1. The synergistic effect of the two drugs was obvious, since only 13% of A2780S and 7% of A2780CP cells remained alive after 24 h of treatment with both MA1 and cisplatin. Moreover, we examined the expression of bcl2, p53, caspase3/9 genes at RNA and protein levels using RT-qPCR and Western blot, respectively, to figure out the cell death mechanism induced by MA1. A significant down-regulation in bcl2 and p53 genes was observed in treated cells compared to non-treated cells (p < 0.05), suggesting that MA1 may not follow the canonical pathway to induce apoptosis in ovarian cancer cell lines. MalforminA1 showed promising anticancer activity by inducing cytotoxicity in cisplatin-sensitive and cisplatin-resistant cancer cell lines. Interestingly, a synergistic effect was observed when MA1 was combined with cisplatin, leading to it overcoming its resistance to cisplatin.

Circulating activated neutrophils in COVID-19: An independent predictor for mechanical ventilation and death.

OBJECTIVES: Critical illness in COVID-19 is attributed to an exaggerated host immune response. Since neutrophils are the major component of innate immunity, we hypothesize that the quantum of activated neutrophils in the blood may predict an adverse outcome. DESIGN: In a retrospective study of 300 adult patients with confirmed COVID-19, we analyzed the impact of neutrophil activation (NEUT-RI), interleukin-6 (IL-6) and the established clinical risk factors of age, diabetes, obesity and hypertension on the clinical outcome. RESULTS: Significant predictors of the need for mechanical ventilation were NEUT-RI (Odds Ratio (OR) = 1.22, P < 0.001), diabetes (OR = 2.56, P = 0.00846) and obesity (OR = 6.55, P < 0.001). For death, the significant predictors were NEUT-RI (OR = 1.14, P = 0.00432), diabetes (OR = 4.11, P = 0.00185) and age (OR = 1.04, P = 0.00896). The optimal cut-off value for NEUT-RI to predict mechanical ventilation and death was 52 fluorescence intensity units (sensitivity 44%, specificity 88%, area under the curve 0.67 and 44%, 86%, 0.64, respectively). CONCLUSION: This finding supports an aberrant neutrophil response in COVID-19, likely due to uncontained viral replication, tissue hypoxia and exacerbated inflammation, introduces a novel biomarker for rapid monitoring and opens new avenues for therapeutic strategies.

Overlapping demyelinating syndrome (Neuromyelitis optica spectrum disorders NMOSD with anti-NMDA receptor encephalitis); A case report.

Neuromyelitis optica spectrum disorder (NMOSD) represents an evolving spectrum of inflammatory demyelinating central nervous system-based autoimmune diseases; while anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is another severe immune-mediated syndrome that occurs in association with IgG antibodies against the GluN1 subunit of the NMDAR and has been predominantly reported in young females (Dalmau et al., 2008 Dec). Although It has been recognized that anti-NMDAR encephalitis can coexist in the same patient who has serological markers of another autoimmune disease (e.g. neuronal autoantibodies and demyelination AQP4 or MOG antibodies) (Titulaer et al., 2014), rare cases are reported with anti-NMDAR encephalitis that overlap with a demyelinating syndrome; such as neuromyelitis optica spectrum disorders associated with Anti- Aquaporin 4 (AQP4) antibodies (Titulaer et al., 2013). We report here an unusual and rare overlapping autoimmune syndrome in a young Omani female who first presented in 2011 with the clinical and radiological presentations of neuromyelitis optica spectrum disorder (NMOSD) and had a complete recovery. Five years later, she was admitted with the diagnosis of anti-NMDAR encephalitis and was found to have positive serum as well as CSF analyses results for AQP4 and anti-NMDAR antibodies. The patient showed significant improvement, for both clinical syndromes with good response to steroid and immunomodulating therapy.

A Decade Experience on Severe Combined Immunodeficiency Phenotype in Oman, Bridging to Newborn Screening.

Introduction: Severe combined immunodeficiency (SCID) results from various monogenic defects that impair immune function and brings on early severe and life-threatening infections. The main stay of treatment for SCID is hematopoietic stem cell transplant (HSCT) with near normal survival at 5 years for an early transplant done at or before the age of 3.5 months of life and the patient is maintained free of infections. Although overall rare, it constitutes a major burden on affected children, their families and on the health system especially in communities with a high rate of consanguinity where incidence and prevalence of recessive inborn errors of immunity (IEI) are expected to be high. Method: Here, we report the clinical, immunological, and molecular findings in 36 children diagnosed with SCID from a single tertiary center in Oman for the last decade. Results: We observed a median annual incidence rate of 4.5 per 100,000 Omani live births, and 91.7% of affected children were born to consanguineous parents. Twenty-three children (63.9%) fulfilled the criteria for typical SCID. The median age at onset, diagnosis and diagnostic delay were 54, 135, and 68 days, respectively. The most common clinical manifestations were pneumonia, septicemia, and chronic diarrhea. Eleven children (30.6%) have received hematopoietic stem cell transplant (HSCT) with a survival rate of 73%. The most frequent genetic cause of SCID in this cohort (n = 36) was (RAG-1), encoding for recombination activating gene (n = 5, 13.9%). Similarly, Major histocompatibility complex type II deficiency accounted for (n = 5, 13.9%) of our cohort. Conclusion: Our report broadens the knowledge of clinical and molecular manifestations in children with SCID in the region and highlights the need to initiate newborn based screening program (NBS) program.

A randomized trial of serological and cellular responses to hepatitis B vaccination in chronic kidney disease.

BACKGROUND: Chronic kidney disease (CKD) is associated with an increased risk of hepatitis B infection and impaired seroconversion to hepatitis B vaccine (HBV). Studies examining augmented vaccine schedules to enhance seroconversion have so far been inconclusive. Furthermore, the defects responsible for impaired vaccine immunity in CKD have not yet been identified. METHODS: We studied serological and cellular responses to HBV in CKD to identify a defect in vaccine-induced cellular responses that could account for impaired seroconversion in CKD and clarify the effects of an augmented vaccine dose schedule. We compared these results with responses to seasonal influenza vaccination (Fluvax). RESULTS: We found a clear benefit in rates and magnitude of seroconversion after an augmented 40mcg HBV dose schedule in CKD. This permitted comparison of responders and non-responders. Serological non-responders with CKD exhibited reduction in CXCR3+CCR6- CXCR5+ memory T cells at baseline. Unlike Fluvax, HBV elicited a poor plasmablast (PB) response. Both vaccinations induced activation of the CXCR3+CCR6- CCR7- subset of circulating T follicular helper cells (cTFH), although this response was impaired in CKD after HBV. CONCLUSIONS: CKD confers a specific T cell defect that contributes to the impaired seroconversion to HBV.

Determination of an Aspergillus fumigatus-Specific Immunoglobulin G Reference Range in an Adult Omani Population.

OBJECTIVES: The presence of abnormally high levels of Aspergillus fumigatus-specific immunoglobulin (Ig) G antibodies can serve as a diagnostic criterion for severe conditions like allergic bronchopulmonary and chronic pulmonary aspergillosis. This study aimed to determine a reference range of A. fumigatus-specific IgG levels within a healthy adult Omani population. METHODS: This study took place during November 2015 at the Sultan Qaboos University Hospital, Muscat, Oman. The sera of 125 healthy Omani blood donors were tested for A. fumigatus-specific IgG levels using an automated fluorescence enzyme immunoassay. RESULTS: Initially, the data were not normally distributed; however, log transformation and the exclusion of four outliers resulted in an acceptable Gaussian distribution. The reference range was 2.0-68.7 mgA/L at the 2.5th and 97.5th percentiles, respectively, with 90% confidence intervals of 2.0-3.0 mgA/L and 48.0-76.0 mgA/L, respectively. CONCLUSION: The A. fumigatus-specific IgG reference range within a healthy adult Omani population was comparable to those reported in other populations.

STAT3 regulates cytotoxicity of human CD57+ CD4+ T cells in blood and lymphoid follicles.

A subset of human follicular helper T cells (TFH) cells expresses CD57 for which no distinct function has been identified. We show that CD57+ TFH cells are universally PD-1hi, but compared to their CD57- PD-1hi counterparts, express little IL-21 or IL-10 among others. Instead, CD57 expression on TFH cells marks cytotoxicity transcriptional signatures that translate into only a weak cytotoxic phenotype. Similarly, circulating PD-1+ CD57+ CD4+ T cells make less cytokine than their CD57- PD-1+ counterparts, but have a prominent cytotoxic phenotype. By analysis of responses to STAT3-dependent cytokines and cells from patients with gain- or loss-of-function STAT3 mutations, we show that CD4+ T cell cytotoxicity is STAT3-dependent. TFH formation also requires STAT3, but paradoxically, once formed, PD-1hi cells become unresponsive to STAT3. These findings suggest that changes in blood and germinal center cytotoxicity might be affected by changes in STAT3 signaling, or modulation of PD-1 by therapy.

Food Allergen Sensitisation Patterns in Omani Patients with Allergic Manifestations.

OBJECTIVES: This study aimed to evaluate the relationship between food allergen sensitisation patterns and allergic manifestations in Omani patients and highlight the importance of specific immunoglobulin E (IgE) testing. METHODS: This retrospective study included all patients referred due to allergic manifestations to the Sultan Qaboos University Hospital (SQUH), Muscat, Oman, from November 2012 to November 2016. Specific IgE blood testing was performed to determine sensitisation to common foods known to cause allergic reactions. RESULTS: A total of 164 patients were referred to SQUH over the study period, with 35.4% presenting with one allergic manifestation, 48.8% with 2-3 and 15.9% presenting with more than three manifestations. There was a family history of allergies in 70.7% of patients. Eosinophil counts and total and specific IgE levels were elevated in 18.9%, 54.9% and 73.2% of patients, respectively. Patients demonstrated sensitisation to cow milk (47.6%), wheat (41.5%), chicken eggs (34.8%), mixed tree nuts (34.1%), lentils (33.5%), peanuts (32.9%), soy (32.3%), shrimp (23.2%) and fish (15.2%). Overall, 19.5% were sensitised to a single allergen, 14% were sensitised to 2-3 and 39.6% were sensitised to more than three allergens. Almost one-third (29.3%) of patients suffered from food-induced anaphylaxis, of which 85.4% were prescribed self-injectable adrenaline. CONCLUSION: To the best of the authors' knowledge, this study is the first to describe food allergen sensitisation patterns among Omani patients with allergic manifestations. In conjunction with clinical symptoms, the correct interpretation of specific IgE levels is important to diagnose food allergies and make safe decisions about reintroducing foods.

Agammaglobulinaemia despite terminal B-cell differentiation in a patient with a novel LRBA mutation.

Mutations in lipopolysaccharide-responsive vesicle trafficking, beach and anchor-containing protein (LRBA) cause immune deficiency and inflammation. Here, we are reporting a novel homozygous mutation in LRBA allele in 7-year-old Omani boy, born to consanguineous parents. He presented with type 1 diabetes, autoimmune haematological cytopenia, recurrent chest infections and lymphocytic interstitial lung disease. The patient was treated with CTLA4-Ig (abatacept) with good outcome every 2 weeks for a period of 3 months. He developed complete IgG deficiency, but remarkably, histological examination revealed germinal centres and plasma cells in lymphoid and inflamed lung tissue. Further charatecterisation showed these cells to express IgM but not IgG. This ex vivo analysis suggests that LRBA mutation confers a defect in class switching despite plasma cell formation.

Heterophile interference accounts for method-specific dsDNA antibodies in patients receiving anti-TNF treatment.

OBJECTIVE: To evaluate analytical explanations for the highly reported incidence of antibodies to dsDNA in patients receiving TNF antagonists. METHODS: Sixty serum samples from patients receiving biological anti-TNF medication were assessed for the presence of dsDNA antibodies using three standard diagnostic platforms [ELISA, IIF and multiplex bead array (MBA)], before and after treatment to block heterophile antibodies. Results were compared with those obtained using serum samples from patients with SLE. RESULTS: We identified significant method-specific discrepancies in the estimation of dsDNA antibodies in patients receiving TNF antagonists. dsDNA antibodies were frequent according to ELISA and IIF, but rare according to MBA. Blockade of heterophile antibodies resulted in a significant reduction in titres of dsDNA antibodies detected by IIF. In contrast, there was a much greater consistency for dsDNA antibody results in SLE, especially for those present in high titre, and blockade of heterophile antibodies did not result in a change between the two paired samples by IIF or MBA. CONCLUSION: There is a significant method-specific variation in the detection of dsDNA antibodies in patients receiving TNF antagonists, due in part to the effects of heterophile antibodies.