Assessment of the influence of Fc-γ receptor polymorphisms on biologics' pharmacokinetics in Tunisian rheumatoid arthritis patients.

AIMS: This study aims to determine whether a modification in Fc-γ receptors' (FcgRs) affinity to Fc portion, caused by single nucleotide polymorphisms such as rs1801274-R131H FcgRIIa, rs396991-F158V FcgRIIIa and NA1/NA2-FcgRIIIb, might impact clearance of therapeutic monoclonal antibodies and thus serum drug levels and the development of anti-drug antibodies. METHODS: A cross sectional, multicentral and noninterventional study was conducted in Tunisian RA patients treated with rituximab (RTX), etanercept (ETA), infliximab (IFX) and adalimumab (ADL). Serum drug level (SDL) of the different biologics and ADA against them were measured. All patients were genotyped for the 3 FcgR single nucleotide polymorphisms. RESULTS: A total of 81 patients were included: 47 were under tumour necrosis factor inhibitors (18 ETA, 13 ADL and 16 IFX), and 34 were under RTX. Regardless of the type of biotherapy, SDL was in therapeutic range, in 35 patients (43.2%), of whom only 1 was treated with RTX. Fourteen patients (22.2%) developed ADA, but none of the patients treated with ETA had detectable ADA levels. There was no association between SDL positivity and FcgR polymorphisms. However, the high affinity FcgR2A 131 H/H receptor was statistically more prevalent in patients with detectable ADA treated with ADL, IFX and RTX (P = .018). The same result was obtained in the monoclonal antibody tumour necrosis factor inhibitor subgroup (n = 29, P = .022) as well as in patients treated only with IFX (n = 16, P = .029). CONCLUSION: Our work supports the hypothesis of an impact of FcgR single nucleotide polymorphisms on biologics' immunogenicity, particularly FcgR R131H polymorphism, but further studies with larger cohorts need to be undertaken to confirm these results.

Thrombotic microangiopathy due to acquired complement factor I deficiency in a male receiving interferon-beta treatment for multiple sclerosis.

AIMS: Interferon-beta (IFNß), the most widely prescribed medication for multiple sclerosis, is generally considered safe. Nevertheless, rare serious and/or life-threatening side effects have been reported such as thrombotic microangiopathy. A few mechanisms have been proposed to explain how interferon causes thrombotic microangiopathy, but immunological studies have been unable to pin this phenomenon down to a single pathophysiologic pathway. The aim of this article was to report a new mechanism explaining Interferon beta related thrombotic microangiopathy. METHODS: We report thrombotic microangiopathy in a 28-year-old male receiving interferon-beta treatment for multiple sclerosis. RESULTS: After three years of starting interferon beta therapy, the patient presented with malignant hypertension causing seizures, rapidly progressive renal failure requiring haemodialysis and haemolytic anaemia. Corticosteroid and plasma exchange sessions permitted haemolysis control. Nonetheless, the patient remained hemodialysis-dependent. Exploration of the complement system found a complement factor I deficiency whose activity normalized at the control carried out after 2 years. CONCLUSION: IFNß treatment may cause complement factor I deficit, which can lead to thrombotic microangiopathy and severe renal failure.

Pre- and Post-treatment Serum BAFF Levels and BAFF Gene Polymorphisms in Patients with Graves' Disease.

BACKGROUND: B cell activating factor (BAFF), a crucial factor for B cell survival and differentiation, has been linked to several autoimmune conditions. The aim of this study was to evaluate the association of BAFF gene's polymorphisms with its serum levels and to assess their effect on Graves' disease (GD) susceptibility and presentation. METHODS: Sixty-two GD patients and 152 healthy controls have been enrolled to investigate BAFF rs9514827 (-2841 T/C), rs1041569 (-2701 T/A) and rs9514828 (-871 C/T) gene's polymorphism by PCR-RFLP and serum BAFF level's kinetics under medical treatment by ELISA. RESULTS: Median serum BAFF level at baseline was significantly higher in GD patients (841.7 pg/ml [685.23-1058.32]) comparatively to controls (495.75 pg/ml [383.17-595.7]), p = 7.29 E-25. A ROC curve was used to assess BAFF performances in GD diagnosis and revealed an AUC of 94.9% [0.919-0.979], p = 7.29 E-25. At a cutoff value of 654.9 pg/ml of BAFF at baseline, the sensitivity and the specificity were, respectively, 83.9% and 90.8%. BAFF level was significantly increased in smoking patients (1079.55 pg/ml [875.35-1203]) comparatively to nonsmokers (746.95 pg/ml [643.2-915.7]), p = 3.1 E-5. While -2841 T/C and -2701 T/A genotypes and alleles frequencies were similar between patients and controls, the -871*T allele was significantly more prevalent in patients (0.613) than in controls (0.477); p = .01, OR [95% CI] = 1.73 [1.13-2.65]. The three studied polymorphisms were not associated with serum BAFF level at baseline. CONCLUSION: Serum BAFF level is significantly increased in GD especially in smoking patients. rs9514828 - 871*T allele might be a susceptibility variant for GD.

Molecular basis of complement factor I deficiency in Tunisian atypical haemolytic and uraemic syndrome patients.

AIM: The aim of the present study was to characterize the molecular basis of complement factor I deficiency in Tunisian atypical haemolytic and uremic syndrome patients with low factor I levels. METHODS: Six adults and seven children were enrolled in this study. Complement factor I levels were assessed by a homemade sandwich ELISA and ranged between 12.5% and 60%. Genomic DNA was amplified by way of a polymerase chain reaction using intronic primers flanking the 13 coding exons. Sequencing of amplified products was carried out by the dye terminator sequencing method. Molecular study was performed on parental samples for three dead paediatric patients. The control group consisted of 100 healthy Tunisian donors. RESULTS: We identified a total of 13 substitutions and one insertion: seven in introns, four in exons and three in UTR. The new mutations were c.-132G > C, c.71 + 181 T > A in 5'UTR and intron 1, respectively. Three intronic polymorphisms were predicted to have impact on splicing events: c.482 + 6C > T, c.884-42_884-41insTTAAA (rs34422850) and c.1429 + 33 A > G (rs9998151). They were three missense mutations leading to a p.Ile 357Met, p.Ile416Leu and p.GLu548Gln. p.Ile 357Met was found in two patients and one relative. Half of the patients had associated mutation and/or polymorphisms. CONCLUSION: This is the first genetic study in Tunisian and Maghrebin atypical haemolytic and uraemic syndrome patients. The high occurrence of Ile357Met mutation may reflect a founding effect. Functional impact of the two new mutations c.-132G > C and c.71 + 181A > T have to be studied. Association of simultaneous genetic abnormalities may explain the variability of atypical haemolytic and uraemic syndrome, penetrance and disease phenotype.

Response to clopidogrel and of the cytochrome CYP2C19 gene polymorphism.

INTRODUCTION: Clopidogrel (clopi) is a prodrug widely prescribed in the management of coronary artery disease and requires the intervention of hepatic cytochrome P450 2C19 (CYP2C19) for its activation. However, there is interindividual variability in response to clopi despite the use of recommended doses. Thus, the studies have highlighted the effect of the CYP2C19 gene polymorphism or Cyp2C19 gene on the response to clopi and particularly Cyp2C19 * 2 which may be associated with an increased risk of major cardiovascular events or MACE. OBJECTIVE: To evaluate the effect of Cyp2C19 * 2 polymorphism on MACE occurrence and hemorrhagic complications in patients treated with clopi. METHODS: We carried out a descriptive longitudinal study including 71 patients placed under clopi for a minimum duration of one month. Genotyping of the Cyp2C19 allele was performed by conventional polymerase chain reaction (PCR). After a follow-up period of 495 ± 183 days, we performed a statistical analysis to evaluate the association between the Cyp2C19 * 2 polymorphism and the occurrence of MACE or hemorrhagic complications. RESULTS: Among our patients, 51% had an angioplasty, 42% medical treatment and 7% a coronary artery bypass surgery. In our study population, 52% were heterozygous (HTZ), 28% homozygous (HMZ) healthy * 1 / * 1 and 20% HMZ had the loss of function allele * 2 / * 2. The allelic frequency of Cyp2C19 * 2 was 46%. Follow-up mean duration was of 495 ± 183 days. During this period, the prevalence of MACE was 11% and that of hemorrhagic complications was 13%. In our study, we did not observe a significant association between the occurrence of MACE or hemorrhagic complications with the genotype carrying the Cyp2C19 * 2 allele. CONCLUSION: Among patients treated with clopi, wearing a Cyp2C19 * 2 function loss allele didn't seem to be associated with a significantly higher risk of MACE, nor a significantly lower risk of hemorragic complications. This suggests the necessity of larger studies.

Complement Component C3 Variant (R102G) and the Risk of Neovascular Age-Related Macular Degeneration in a Tunisian Population.

Purpose To explore the association between the polymorphism (S/F) p.R102G in the complement component 3 (C3) gene and age-related macular degeneration (AMD) in a Tunisian population. Methods The molecular study was performed by polymerase chain reaction using sequence-specific primers (PCR-SSP) in 207 control subjects free of any eye disease (fundus normal) and 145 patients with exudative AMD. The CH50 activity and quantification of C3 and C4 have been made by technical home method and nephelometry, respectively. Results The prevalence of C3 GG genotype polymorphism was significantly higher in AMD patients compared to controls (OR: 2.41, IC 95% [1.90-3.05], p = 0.0007). However, no correlation was found between this allelic variant and the type of neovascularization. Similarly, there is no association between this polymorphism and the presence of functional and/or quantitative hypocomplementemia. Conclusions The C3 GG genotype of the gene could be a susceptibility factor for AMD in the Tunisian population. However, it does not seem to influence the clinical profile of the disease.

[The epithelial-mesenchymal transition and fibrosis of the renal transplant]. / La transition épithélio-mésenchymateuse et la fibrose du transplant rénal.

Epithelial-mesenchymal transition (EMT) is a process by which differentiated epithelial cells undergo a phenotypic conversion and acquire a mesenchymal phenotype, including elongated morphology, enhanced migratory and invasion capacity, and greatly increased production of extracellular matrix (ECM) components. This phenomenon plays a pivotal role in embryonic development, wound healing and tissue regeneration. It has also been involved in organ fibrosis. Some studies suggest that following injury, renal tubular epithelial cells undergo reprograming in mesenchymal cells, and thus constitute an important source of de novo myofibroblasts invading the renal interstitium and contributing to fibrosis. However, an increasing number of studies raise doubts about the existence of this process in vivo. The role of EMT in the development of renal fibrosis remains a matter of intense debate and may depend on the model studied. In this review, we describe the role of EMT in the development of fibrosis of renal graft, and then we propose approaches for detecting and treating renal fibrogenesis by targeting TEM.

Impact of IL-10 gene promoter polymorphisms on treatment response in HCV patients: A systematic review, a meta-analysis, and a meta-regression.

The impact of interleukin-10 (IL-10) gene promoter polymorphisms (SNPs) on treatment response in HCV patients was dissimilarly estimated. Hence, the aim of this meta-analysis was to robustly assess the effect of IL-10 SNPs on treatment response in HCV patients. An electronic literature search was carried out through PubMed, EMBASE, Web of science, and Scopus databases. Studies assessing the association between IL-10 polymorphisms and treatment response in HCV patients were included. Studies were excluded if genotype frequencies are not consistent with the Hardy-Weinberg Equilibrium (HWE) or in case of including patients with hepatitis B virus coinfection. Risk of bias in included studies was assessed using the Newcastle-Ottawa Scale. Meta-analyses were performed for the influence of IL-10 gene promoter SNPs (rs1800896 (-1082 A/G), rs1800871 (-819 C/T), and rs1800872 (-592 C/T)) and haplotypes on treatment response in HCV patients. Subgroup analyses, meta-regressions, publication bias assessment, and sensitivity analyses were also conducted. Overall, 32 studies with a total of 5943 HCV cases and 2697 controls were included in the present study. The -1082*G allele was significantly associated with increased risk of non-response (NR) to treatment, OR [95% CI] = 1.29 [1.1-1.51], p = .002. Besides, the rs1800872 -592*C allele was significantly associated with increased NR risk, OR [95% CI] = 1.22 [1.02-1.46], p = .03. Subgroup analysis showed that this association remained significant only in patients treated with PEG-IFN alone, p = .01. The -1082*G/-819*C/-592*C (GCC) haplotype was significantly associated with increased NR risk, OR [95% CI] = 1.62 [1.13-2.23], p = .009. Our results suggest that the IL-10 rs1800896 was associated with NR risk especially in North-African and Asian populations. Moreover, the IL-10 gene promoter -1082*G/-819*C/-592*C (GCC) haplotype which has been associated with higher production of IL-10, was significantly associated with increased NR risk.

Association of HLA class II alleles and haplotypes with bullous and mucus membrane pemphigoid risk: A systematic review, a meta-analysis and a meta-regression.

Although, several studies have assessed the association of HLA Class II and genes with bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP), results were inconsistent and between-studies heterogeneity needs to be investigated. An electronic literature search for eligible studies among all papers published prior to May 31, 2024, was conducted through PubMed, EMBASE, Web of science and Scopus databases. Meta-analyses together with subgroup analyses and meta-regressions were performed for the three following HLA genes: DRB1, DQA1 and DQB1. Combined analyses revealed a significant increase in pemphigoid risk conferred by the following alleles: DQB1*0301, DRB1*11, DRB1*1101 subtype and DQA1*0505, all p-values <.001. However, there was a moderate to high level of between-studies heterogeneity. Subgroup analyses revealed that the risk conferred by the aforementioned alleles was significantly higher in case of dipeptidyl peptidase-4 inhibitors induced BP (DBP) comparatively to idiopathic BP and MMP. In addition, the risk conferred by the DQB1*0301 was significantly higher in MMP (OR [95% CI] = 5.25 [4.03-6.84]) than in BP (OR [95% CI] = 2.22 [1.87-2.65]), p = .007. Besides, the DRB1*1101-DQB1*0301 and DRB1*11-DQA1*05-DQB1*0301 haplotypes were significantly associated with an increased pemphigoid risk, both p-values <.001. Conversely, the DQA1*0201 allele was significantly associated with reduced pemphigoid risk (OR [95% CI] = 0.3 [0.17-0.52]), with no between-studies heterogeneity (I2 = 0%, p = .76). This meta-analysis demonstrated that the DRB1*1101, DQA1*0505 and DQB1*0301 were significantly associated with increased pemphigoid risk. These associations were found to be significantly stronger in case of DBP comparatively to idiopathic pemphigoid. The DQA1*0201 allele seems to play a protective role against pemphigoid. Registration: This review has been registered on PROSPERO: CRD42024552821, Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024552821.

Association of 10 Polymorphisms in PLA2R1 and HLA DQA1 Genes with Primary Membranous Nephropathy Risk: A Meta-Analysis and a Meta-Regression.

Background: Although, several studies have assessed the association of the phospholipase A2 receptor (PLA2R) and HLA-DQA1 SNPs with primary membranous nephropathy (PMN), results were inconsistent and between-studies heterogeneity needs to be investigated. Objectives: The aim of this review was to summarize existing data on the contribution of 10 SNPs in the PLA2R and HLA-DQA1 genes to PMN susceptibility and to investigate the between-studies heterogeneity by subgroup analyses and meta-regressions. Design: This study was performed according to the PRISMA guidelines for systematic reviews and meta-analyses. Data sources and methods: An electronic literature search for eligible studies among all papers published prior to January 10, 2024, was conducted through PubMed, EMBASE, Web of science and Scopus databases. Meta-analyses together with subgroup analyses and meta-regressions were performed for the 10 following SNPs: rs4664308, rs3749117, rs3749119, rs35771982, rs3828323, rs16844715, rs1511223, rs6757188, rs2715918, and rs2187668. Results: Combined analyses revealed a significant increase in PMN risk conferred by the following alleles: rs4664308*A, rs3749117*T, rs3749119*C, rs35771982*G, rs3828323*C, rs16844715*C, rs1511223*A, rs2715918*A, and rs2187668*A, all P-values < .001. Moreover, the PLA2R-rs4664308/HLA-DQA1-rs2187668 interaction was significantly associated with an increased PMN risk, P < .001. However, there was a substantial between-studies heterogeneity for some SNPs. Subgroup analyses by ethnicity for the 9 PLA2R SNPs did not show any cross-ethnic disparity. Inversely, the risk conferred by the HLA-DQA1 rs2187668*A allele was significantly higher in Caucasians (OR [95% CI] = 3.929 [3.251-4.748]) than in Asians (OR [95% CI] = 2.537 [1.94-3.318], P = .007. Besides, meta-regressions revealed for the majority of investigated SNPs significant correlations of the effect size with albumin, 24-hours proteinuria, serum creatinine, and eGFR levels. Hence, the influence on PMN risk conferred by the PLA2R and HLA-DQA1 SNPs was rather noted in patients with a severe disease. Conclusion: This meta-analysis showed that 9 out of the 10 investigated SNPs in PLA2R and HLA-DQA1 genes were associated with increased PMN risk. Heterogeneity could be due to disparate patient groups in terms of disease presentation for almost all SNPs, and ethnicity for the HLA-DQA1 rs2187668 SNP. Registration: This review has been registered on PROSPERO: CRD42024506729. Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024506729.

Genetic factors in primary membranous nephritis Why was the study done? Primary membranous nephritis (PMN) is the most common etiology of adult-onset nephrotic syndrome. Understanding risk factors, particularly genetic ones, would provide a better understanding of its pathophysiological mechanisms in order to prevent and treat patients more effectively. What did the researchers do? The research team summarized published data on genetic factors associated with PMN including phospholipase A2 receptor (PLA2R) and HLA-DQA1 genes. What did the researchers find? The total number of included studies was 27. Nine out of ten genetic factors were found to be associated with PMN risk. Moreover, we noted significant interaction between PLA2R and HLA-DQA1 in potentializing PMN risk. Nevertheless, there was a significant between-studies heterogeneity which was found to be explained in part by disease severity. What do the findings mean? This study has identified some important some genetic factors associated with PMN together with confounding factors that could influence the aforementioned association.

Association of four CTLA-4 gene polymorphisms with pemphigus risk: a systematic review, meta-analysis, and meta-regression.

OBJECTIVES: This review aimed to summarize the existing data on the contribution of four single nucleotide polymorphisms (SNPs) in the cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) genes to pemphigus susceptibility. METHODS: An electronic literature search for eligible studies among those published prior to 30 April 2024 was conducted through the PubMed, EMBASE, Web of Science, and Scopus databases. To minimize publication bias, an additional search was performed via the Google Scholar and Semantic Scholar search engines. Meta-analyses, together with subgroup analyses and meta-regressions, were performed for the following four CTLA-4 SNPs: rs231775, rs5742909, rs3087243, and rs733618. RESULTS: Combined analyses revealed a significant increase in pemphigus risk conferred by the CTLA-4 rs5742909*C and rs733618*C alleles. Conversely, there was no evidence of any significant association between the rs231775*G and rs3087243*G alleles and susceptibility to pemphigus. Subgroup analyses by ethnicity and pemphigus type (vulgaris or foliaceus) and meta-regressions did not reveal any significant difference. CONCLUSION: This meta-analysis suggested that two of the four investigated CTLA-4 SNPs were significantly associated with increased pemphigus risk.Registration: This review has been registered on PROSPERO: CRD42024550668; available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024550668.

Knowledge and Attitudes Toward Organ Donation Among Tunisian Adults: Results of a National Survey.

OBJECTIVES: Attitudes and knowledge toward organ donation can influence a person's willingness to donate. The aim of this study was to assess attitudes and knowledge regarding organ donation among Tunisian adults. MATERIALS AND METHODS: We conducted a crosssectional survey at the national level from January 23 to February 15, 2017, among 1026 Tunisian adults. We used a standardized questionnaire to collect data by phone call. We performed statistical analyses with Stata software (version 11). RESULTS: The study included 495 male and 531 female participants. Forty-one percent of participants were 18 to 30 years old. In total, 81.7% had heard about organ donation. Fewer than half of respondents (47.8%) were aware that organ donation is regulated. In total, 80.7% accepted to donate their organs after death, and 32.2% had mentioned their opinion to relatives or friends. Only 1% had added their donor status on their national identity cards. CONCLUSIONS: Tunisian adults seem to have positive attitudes regarding organ donation. However, the proportion of respondents who included their donor status on their national identity cards was low. It is important to enhance information and education on organ donation in an effort to mitigate the shortage of organs.

A regression predictive model for QuantiFERON-TB Gold Plus® indeterminate results in immunosuppressed patients.

Background: Screening for latent tuberculosis infection using Interferon-Gamma Release Assays is a routine procedure prior to the initiation of anti-tumor necrosis factor (TNF) biotherapy or immunosuppressive therapy. However, indeterminate results are relatively frequent and are an obstacle to treatment initiation. Aim: The aim of this cross-sectional study was to estimate the frequency of indeterminate QuantiFERON-TB Gold Plus® test results in Tunisian patients, and to analyze the potential clinico-biological risk factors associated with these indeterminate results. Methods: Whole blood samples from 712 patients being monitored for autoimmune diseases and candidates for anti-TNF biotherapy or switch of immunosuppressive therapy were used to screen for latent tuberculosis infection using the QuantiFERON-TB Gold Plus® test. Based on literature background, the following variables were tested for the association with indeterminate results: gender, age, diabetes, immunosuppressive drugs, lymphocyte count, Neutrophil-to-lymphocyte ratio, serum albumin, and estimated glomerular filtration rate. Results: The QuantiFERON-TB Gold Plus® test was negative in 572 (80.3%) patients, positive in 106 (14.9%), and indeterminate in 34 (4.8%) cases. Positive results were significantly associated with a family history of confirmed and treated tuberculosis, OR (95% CI) = 52 (20.2-134.3). The use of immunosuppressive drugs and duration of treatment were significantly associated with the occurrence of indeterminate results: OR (95% CI) = 24.5 (5.8-103) and OR (95% CI) = 1.004 (1.002-1.007), respectively. Biologically, lymphopenia, hypoalbuminemia, and decreased estimated glomerular filtration rate were significant risk factors for indeterminate results: p = 5 E-6, p = 4.3 E-4, and p = 0.002, respectively. Thus, a multiple logistic regression model based on these three biological parameters enabled us to develop a predictive score for indeterminate results with a sensitivity of 91.2% and a specificity of 99.9%, AUC = 0.9964 (0.9917-1), p = 2.8 E-52. Conclusion: Immunosuppressive therapy, lymphopenia, hypoalbuminemia, and kidney failure appeared to be risk factors for indeterminate QuantiFERON-TB Gold Plus® results.

Access to kidney transplantation for patients with end-stage renal failure in Maghreb countries: state of art and recommendations / Accès à la transplantation rénale des patients en insuffisance rénale chronique terminale dans les pays du Maghreb : état des lieux et recommandations

We present an overview of kidney transplantation activity in the Maghreb countries, based on data from the 9th Colloque France-Maghreb (Paris, May 20 and 21, 2022). For Algeria, Morocco and Tunisia, the incidence of end stage renal failure is respectively 120, 130 and 130 per million inhabitants, its prevalence 626, 900 and 833 per million inhabitants and the part of patients with a functional graft of 10.3, 1.8 et 8.5% with an annual number of transplants of 6.5, 0.8 and 8.7 per million inhabitants. Living donor transplants account for 99% of transplants in Algeria, 93% in Morocco and 80% in Tunisia. In conclusion, access to transplantation remains low in the Maghreb countries. All the modalities (living donor with enlargement of the circle of donors, deceased donors) must be further developed. Recommendations were issued to support activity.

Nous présentons un état des lieux de l'activité de transplantation rénale dans les pays du Maghreb à partir des données du 9e Colloque France-Maghreb (Paris, 20 et 21 mai 2022). Pour l'Algérie, le Maroc et la Tunisie, l'incidence de l'insuffisance rénale chronique terminale est respectivement de 120, 130 et 130 par million d'habitants, sa prévalence de 626, 900 et 833 par million d'habitants et la part des patients porteurs d'un greffon fonctionnel est de 10,3, 1,8 et 8,5 % avec un nombre annuel de transplantations de 6,5, 0,9 et 7,7 par million d'habitants. La transplantation avec donneur vivant représente 99 % des transplantations en Algérie, 93 % au Maroc et 80 % en Tunisie. En conclusion, l'accès à la transplantation reste faible dans les pays du Maghreb. Toutes les modalités (donneur vivant avec élargissement du cercle des donneurs, donneurs décédés) doivent être développées. Des recommandations ont été émises pour soutenir cette activité.

Impact of FCGR2A R131H, FCGR3A F158V and FCGR3B NA1/NA2 polymorphisms on response to Fc-containing TNF inhibitors in Tunisian rheumatoid arthritis patients.

OBJECTIVES: Single nucleotid polymorphisms (SNPs) of Fc-gamma receptors (FcgRs), by inducing a variation of their affinity to the Fc-region of immunoglobulins, might influence the efficacy of Fc-containing biologics prescribed in rheumatoid arthritis (RA). Our aim was to investigate associations of FCGR2A, FCGR3A and FCGR3B SNPs with TNF-inhibitors (TNFi)' response in Tunisian RA patients. METHODS: A cross-sectional, observational and analytic multicentric cohort study was conducted in a group of 47 Tunisian RA patients treated with (etanercept [ETA], adalimumab [ADL] and infliximab [IFX]). Treatment outcome was evaluated after 6 months. R131H-FCGR2A, F158V-FCGR3A and NA1/NA2-FCGR3B SNPs were genotyped. RESULTS: The analytic study including all types of TNFi showed that FCGR3A-F/F low-affinity receptor was associated with a greater decrease of DAS28, while FCGR3B-NA1/NA1 high-affinity receptor was associated with a lower decrease of DAS28 in ADL group. Furthermore, both of high affinity receptors FCGR3B-NA1/NA1 and FCGR3A-V/V were more prevalent in non-responders to ADL, according to EULAR criteria. CONCLUSIONS: Identifying reliable biomarkers of response to biologics in RA is necessary to improve responsiveness, preserve joints' functions and structure, and reduce treatment's cost. Our study showed that FCGR3A and FCGR3B polymorphisms might have an impact on TNFis' response in RA Tunisian patients since bad response was more frequent in homozygous carriers of high affinity alleles FCGR3A-V and FCGR3B-NA1.

The effects of the CYP3A5*3 variant on tacrolimus pharmacokinetics and outcomes in Tunisian kidney transplant recipients.

INTRODUCTION: Tacrolimus, exhibits interindividual pharmacokinetic variability and a narrow therapeutic index. The influence of the CYP3A5 6986A>G single nucleotide polymorphism (SNP) on this variability remains a topic of debate. AIM: To assess the impact of the aforementioned SNP on tacrolimus area under curve (AUC0-12h), adverse drug reactions (ADRs), and kidney graft outcomes. METHODS: Blood samples were collected from Tunisian kidney transplants over a five-year period during either the early (<3 months) or late (>3 months) post-transplant phases. Through blood concentration (C0) and AUC0-12h of tacrolimus were measured. Patients were prospectively followed to assess graft outcomes. Polymerase chain reaction of restriction fragment length polymorphism was used for CYP3A5 6986A>G genotyping. RESULTS: Fifty Tunisian kidney recipients receiving tacrolimus were enrolled in the study. Acute and chronic graft rejections were observed in eight and three patients, respectively. Twenty-one patients (42%) reported ADRs. C0 and AUC0-12h, showed a significant difference between CYP3A5*1 carriers (mean C0=4 ng.mL-1 and AUC0-12h=94.37 ng.h.mL-1) and CYP3A5*3/3 or poor metabolizers carriers (mean C0=7.45 ng.mL-1; AUC0-12h=151.27 ng.h.mL-1) (p=0.0001; p=0.003, respectively). Supratherapeutic tacrolimus levels were significantly more common in poor metabolizers (p=0.046; Odds-ratio =1.3; confidence interval 95% [1.12-1.66]). The impact of SNP was significant on C0, AUC0-12h, C0/Dose and AUC0-12h/Dose, only in the late phase (p=0.01, 0.002, 0.012, 0.003 respectively). CONCLUSION: CYP3A5*3 variant was significantly associated with tacrolimus pharmacokinetics but had no impact on graft outcomes.

Development and comparative evaluation of SARS-CoV-2 S-RBD and N based ELISA tests in various African endemic settings.

Management of the COVID-19 pandemic relies on molecular diagnostic methods supported by serological tools. Herein, we developed S-RBD- and N- based ELISA assays useful for infection rate surveillance as well as the follow-up of acquired protective immunity against SARS-CoV-2. ELISA assays were optimized using COVID-19 Tunisian patients' sera and prepandemic controls. Assays were further validated in 3 African countries with variable endemic settings. The receiver operating curve was used to evaluate the assay performances. The N- and S-RBD-based ELISA assays performances, in Tunisia, were very high (AUC: 0.966 and 0.98, respectively, p < 0.0001). Cross-validation analysis showed similar performances in different settings. Cross-reactivity, with malaria infection, against viral antigens, was noticed. In head-to-head comparisons with different commercial assays, the developed assays showed high agreement. This study demonstrates, the added value of the developed serological assays in low-income countries, particularly in ethnically diverse populations with variable exposure to local endemic infectious diseases.

Comparative study of six SARS-CoV-2 serology assays: Diagnostic performance and antibody dynamics in a cohort of hospitalized patients for moderate to critical COVID-19.

BACKGROUND: To overcome the COVID-19 pandemic, serology assays are needed to identify past and ongoing infections. In this context, we evaluated the diagnostic performance of 6 immunoassays on samples from hospitalized patients for moderate to critical COVID-19. METHODS: 701 serum samples obtained from 443 COVID-19 patients (G1: 356 positive RT-PCR patients and G2: 87 negative RT-PCR cases) and 108 pre-pandemic sera from blood donors were tested with 6 commercial immunoassays: (1) Elecsys Anti-SARS-CoV-2, Roche (Nucleocapsid, N), (2) Elecsys Anti-SARS-CoV-2 S, Roche (Spike, S), (3) Vidas SARS-COV-2 IgM/IgG, BioMérieux (S), (4) SARS-CoV-2 IgG, Abbott (N), (5) Access SARS-CoV-2 IgG, Beckman Coulter (Receptor Binding Domain), and (6) Standard F COVID-19 IgM/IgG Combo FIA, SD Biosensor (N). RESULTS: Global sensitivities of the evaluated assays were as follows: (1) Roche anti-N = 74.5% [69.6-79.3], (2) Roche anti-S = 92.7% [84.7-100], (3) Vidas IgM = 74.9% [68.6-81.2], (4) Vidas IgG = 73.9% [67.6-80.1], (5) Abbott = 78.6% [63.4-93.8], (6) Beckman Coulter = 74.5% [62-86.9], (7) SD Biosensor IgM = 73.1% [61-85.1], and (8) SD Biosensor IgG = 76.9% [65.4-88.4]. Sensitivities increased gradually from week 1 to week 3 as follow: (1) Roche anti-N: 63.3%, 81% and 82.1%; (2) Vidas IgM: 68.2%, 83.2% and 85.9%; and (3) Vidas IgG: 66.7%, 79.1% and 86.6%. All immunoassays showed a specificity of 100%. Seropositivity was significantly associated with a higher frequency of critical COVID-19 (50.8% vs. 38.2%), p = 0.018, OR [95% CI] = 1.668 [1.09-2.553]. Inversely, death occurred more frequently in seronegative patients (28.7% vs. 13.6%), p=3.02 E-4, OR [95% CI] = 0.392 [0.233-0.658]. CONCLUSION: Evaluated serology assays exhibited good sensitivities and excellent specificities. Sensitivities increased gradually after symptoms onset. Even if seropositivity is more frequent in patients with critical COVID-19, it may predict a recovery outcome.

Indoleamine 2,3-dioxygenase gene expression and kynurenine to tryptophan ratio correlation with nasopharyngeal carcinoma progression and survival.

INTRODUCTION: Indoleamine 2,3-dioxygenase (IDO) is an immunosuppressive tryptophan-depleting enzyme expressed in nasopharyngeal carcinoma (NPC) tissue. However, IDO has not been reported in the peripheral blood of NPC patients. The aim of this study was to analyze, IDO1 and IDO2 messenger RNA (mRNA) expression, the kynurenine (Kyn) and tryptophan (Trp) plasma levels, their clinical values and their relationship with cytokine levels in NPC. METHODS: We evaluated IDO1 and IDO2 mRNA expression in peripheral blood mononuclear cells (PBMC) by quantitative real-time PCR, plasma Trp and Kyn levels by HPLC, and cytokine levels by ELISA in 75 NPC patients and 51 healthy controls. RESULTS: Compared to controls, IDO1 mRNA expression was significantly upregulated and IDO2 mRNA expression was significantly downregulated in PBMC of patients. Also compared to controls, plasma Kyn levels and Kyn/Trp ratio were significantly higher in patients. At the time of diagnosis, the plasma Kyn/Trp ratio was associated with advanced cancer status and was an independent prognostic factor for worse disease-specific survival. According to cancer stages, IDO1 mRNA expression was positively correlated with plasma Kyn/Trp ratio in patients with earlier stages (I-II-III) but negatively correlated in patients with the late-stage cancer (IV). Tumor necrosis factor-α, interleukin (IL)-6 and IL-10 levels were significantly higher in patients compared to controls. Moreover, and despite treatment, patients simultaneously carrying high plasma Kyn/Trp ratio and high plasma IL-6 and IL-10 levels at diagnosis died approximately 1 year after first diagnosis. CONCLUSION: Measuring blood IDO mRNA expression and Kyn/Trp ratio at diagnosis could be a potential marker to evaluate NPC progression and predict survival outcome.

Interleukin-18 gene polymorphisms in tunisian patients with inflammatory bowel disease.

AIM: Interleukin (IL)-18 can regulate the Th2-mediated immune response and it may be involved in the pathogenesis of Th1 and Th2 chronic inflammatory diseases. This study sought to detect a possible association between two single nucleotide polymorphisms (SNPs) (-137G/C and -607C/A) in the IL-18 gene promoter region and susceptibility to inflammatory bowel disease (IBD) including Crohn's disease (CD) and ulcerative colitis (UC) in the Tunisian population. METHODS: The (-137G/C and -607C/A) IL-18 polymorphism was analyzed in 105 patients with CD, 59 patients with UC, and 100 controls using the sequence-specific polymerase chain reaction method. RESULTS: The distribution of allele and genotype frequencies illustrate that the -137G/G genotype frequency was significantly higher in UC than in controls (p value corrected (pc) = 0.038). On the other hand, we found a statistically significant association (pc = 0.033) between genotype AA of the IL-18 gene promoter (-607C/A) polymorphism in UC patients and the distal localization of the lesions. In CD, no significant differences were observed at positions -607 and -137. The analysis of IBD patients according to clinical behavior revealed no difference. CONCLUSION: The two SNPs at position -607 (C/A) and -137 (G/C) in the promoter region of the IL-18 gene was associated with the development of UC but not CD, providing a strong support for an IBD susceptibility gene in the region surrounding IL-18. It remains to be determined precisely how the IL-18 alleles influence the pathogenesis of IBD.