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.

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.

HLA-A*26-A*30 and HLA-DRB1*10 could be predictors of nasopharyngeal carcinoma risk in high-risk Tunisian families.

We investigated human leukocyte antigen (HLA) profiles for Tunisians with nasopharyngeal carcinoma (NPC), their families, and a sample of unrelated healthy Tunisians in order to identify HLA specificities associated with familial NPC. HLA-A, -B, and -DRB1 typing was successful for 36 NPC patients, 72 unaffected family members, and 130 community controls, and the chi square or Fisher exact test was used to compare allele frequencies between cases and controls. We observed a consistent protective effect of HLA-DRB1*10 on NPC development. However, none of the NPC patients or their family members had a positive result for this HLA marker (0% vs 9.2% in controls, P = 0.047). In addition, HLA-A*26 was probably an induction marker, as its allelic frequency was significantly higher among NPC patients than among controls (P = 0.003) and among NPC patients than among at-risk family members (P = 0.067). Logistic regression analysis of the joint effect of selected HLA specificities showed that HLA-A*26 and HLA-A*30 were co-associated and have an important effect on NPC risk. Despite the small size of our cohort, we showed that HLA-A*26-A*30 and HLA-DRB1*10 might be predictive markers for NPC screening of Tunisian families with a high risk of NPC.

Risk factors and consequences of delayed graft function.

The impact of delayed graft function (DGF) on the outcome of renal transplantation remains controversial. We analyzed the risk factors for DGF and its impact on graft and patient survival. A total of 354 renal transplants performed between June 1986 and April 2000 were analyzed. Variables analyzed included donor and recipient age, method and duration of renal replacement therapy, HLA mismatch, cold and warm ischemia times, biopsy-confirmed acute rejection, length of stay in the hospital, serum creatinine at the end of first hospitalization as well as graft and patient survival at one, three, five and ten years. The study patients were divided into two groups: patients with DGF (G1) and those without DGF (G2). DGF occurred in 50 patients (14.1%), and it was seen more frequently in patients transplanted from deceased donors (60% vs. 40%, P <0.0001). The cause of DGF was acute tubular necrosis, seen in 98% of the cases. Univariate analysis showed a statistically significant difference between the two groups G1 and G2 in the following parameters: average duration on dialysis (52.3 vs. 36.4 months, P = 0.006), HLA mismatch (44.9% vs. 32.11% P = 0.015), donor age (35.9 vs. 40.2 years, P = 0.026), cold ischemia time (23 vs. 18.2 h, P = 0.0016), warm ischemia time (41.9 vs. 38.6 mn, P = 0.046), length of stay in the hospital during first hospitalization (54.7 vs. 33.2 days, P <0.0001), serum creatinine at the end of first hospitalization (140 vs. 112 µmol/L, P <0.0001) and at three months following transplantation (159 vs. 119 µmol/L, P = 0.0002). Multivariate analysis revealed the following independent risk factors for DGF: deceased donor (RR = 13.2, P <0.0001) and cold ischemia time (RR = 1.17, P = 0.008). The graft survival at one, three, five and ten years was 100%, 93%, 88.3% and 78.3% in G1 versus 100%, 95.9% 92.8% and 82.3% in G2; there was no statistically significant difference. The patient survival at one, three, five and ten years was 100%, 91.3%, 83.6% and 74.4% in G1 versus 100%, 95.9%, 94% and 82.6% in G2 with a statistically significant difference (P = 0.04). Prolonged cold ischemia time and transplantation of kidneys from deceased donors were the main risk factors for DGF in our study. Also, DGF significantly affected patient survival but had no influence on graft survival.

Anti-CCP antibodies, rheumatoid factors and anti-keratin antibodies: clinical value in established rheumatoid arthritis.

BACKGROUND: It is well documented that in early rheumatoid arthritis, anti-CCP antibodies have better diagnostic value than rheumatoid factors and anti-keratin antibodies. However, their role is less well defined in patients with established or long duration disease. AIM: To evaluate and to compare diagnostic performances of anti- CCP, anti-keratin, IgM and IgA rheumatoid factors in established rheumatoid arthritis. METHODS: In a cross-sectional study, 90 patients with established rheumatoid arthritis and 100 controls were tested for these autoantibodies. The association of these markers with disease activity and severity was investigated. The sensitivity and specificity were calculated for each of four tests, using the clinical diagnosis as the gold standard. RESULTS: The anti-CCP and IgM rheumatoid factor exhibited the best diagnostic value. None of the tested antibodies had any significant association with the disease activity score (DAS28). After adjustment by multiple linear regression, only anti-CCP positivity was found to be significantly associated with erosive disease. CONCLUSION: In long duration rheumatoid arthritis, anti-CCP and IgM rheumatoid factor have similar diagnostic value. However anti- CCP are useful in seronegative patients. They are also a reliable marker of severe erosive disease.

[IL1/IL1 Ra, CTLA-4 and Apo1/Fas genes polymorphisms and susceptibility to IgA nephropathy in Tunisian patients]. / Polymorphismes des gènes de l'IL1/IL1 Ra, CTLA-4 et Apo1/Fas et susceptibilité à la néphropathie à IgA chez des patients Tunisiens.

BACKGROUND: The IgA nephropathy (IgA-N) is considered the most common form of primary glomerulonephritis and its pathogenic mechanisms are very complex. The study of several genes which encode for immunoregulator molecules in inflammatory and immunological responses during the disease, allowed to describe some number of polymorphisms would be involved in the molecular expression, the road marking, the synthesis and\or the binding to the receptors. So an abnormality of the molecular function associated with its polymorphism would be suggested in the genetic predisposition to the disease. AIM: To determine interleukin 1 (IL1), interleukin1 receptor antagonist (IL1 Ra), CTLA-4 and Apo1/Fas genes polymorphisms frequencies in IgA-N in order to estimate the impact of these polymorphisms in the disease susceptibility. METHODS: The polymorphism of a single nucleotide (SNP) at (-889) IL1 a of 21 IgA-N patients and 100 healthy blood donors, as controls, was studied by PCRSSP. The SNPs of the IL1 ß (+3954), CTLA-4 (+49) and l'Apo1/Fas were analyzed by PCR RFLP and finally the polymorphism of the IL1 Ra gene was determined by a PCR VNTR (variable number tandem repeat). RESULTS: Investigation of IL1a/ß and Apo1/Fas polymorphisms showed no differences in genotypes and alleles frequencies between IgA-N patients and controls. However, genotype AA of CTLA-4 exon1 (+49) was significantly higher in patients (47.62%) than in controls (9.1%) p<0.001. Nevertheless, the clinical, histological and biological characteristics of IgA-N were similar in AA CTLA-4 genotype patients compared to AG or GG genotype patients. We fund also, a significant increased frequency of 1/1 IL1 Ra genotype in IgA-N patients (95.24%) compared to controls (54%) (p<0.001) (p<0.001). CONCLUSION: We conclude that the susceptibility to IgA-N seems to be associated with the presence of CTLA-4 AA and IL1 Ra 1/1 genotypes in Tunisian population. However, the lack of association between IL1 a/ß and Apo1/fas genes polymorphisms should be further investigated by large population based studies.

[Association Budd Chiari syndrome, antiphospholipid syndrome and Grave's disease]. / Association syndrome de Budd Chiari, syndrome des antiphospholipides et maladie de Basedow.

BACKGROUND: Antiphospholipid syndrome is revealed by Budd Chiari syndrome in 5% of the cases. Antiphospholipid syndrome is characterized by venous or arterial thrombosis, foetal loss and positivity of antiphospholipid antibodies, namely lupus anticoagulant, anticardiolipin antibodies and anti-beta2-glycoprotein I. Anticardiolipin antibodies was reported in auto-immune thyroid disorders, particularly in Grave's disease. Antiphospholipid syndrome associated to Grave's disease was reported in only three cases. AIM: To describe a case report of association of Grave's disease and antiphospholipid syndrome. OBSERVATION: We report the first case of Grave's disease associated with antiphospholipid syndrome, revealed by Budd Chiari syndrome. CONCLUSION: Our observation is particular by the fact that it is about a patient presenting a Grave's disease associated with antiphospholipid syndrome revealed by Budd Chiari syndrome. This triple association has never been reported in literature. Although association between antiphospholipid syndrome and Grave's disease was previously described, further studies evaluating the coexistence of these two affections in the same patient would be useful.

[Auto-immune serological disorders in chronic viral C hepatitis: prevalence and clinical significance]. / Anomalies serologiques auto-immunes au cours de l'hepatite chronique virale C: prevalence et signification clinique.

BACKGROUND: Hepatitis C viral (HCV) infection has been shown to lead to auto-immune phenomena. AIMS: We review the prevalence of serological auto-immune disorders associated to HCV infection and to clarify their clinical significance. METHODS: Literature review. RESULTS: The serological immune response to HCV infection may include the development of cryoglobulinemia, rheumatoid factor, anticardiolipin, antinuclear, anti-liver-kidney-microsome 1 and anti-smooth muscle antibodies. Serological auto-immune manifestations were explained by the lymphotropism of HCV and the polyclonal activation of B cells. Interferon-based treatment of HCV infection may precipitate or exacerbate the associated auto-immune disease. CONCLUSION: In patients with serological auto-immune disorders associated with HCV infection, a very careful analysis of clinical and biological features is needed. Application of classification criteria of systemic auto-immune diseases and testing more specific antibodies can resolve this point.