Pyrenophora tritici-repentis in Tunisia: Race Structure and Effector Genes.

Tan spot is a destructive foliar wheat disease worldwide and caused by the ascomycete fungus Pyrenophora tritici-repentis (Ptr); it has become more frequent in Tunisia over the last decade. In this study, the virulence of 73 single-spore isolates, collected from durum and bread wheat fields during 2017-2018 growing season, was evaluated on four differential wheat genotypes. This was followed by polymerase chain reaction tests with specific primers for the effector genes ToxA, ToxB, and toxb (ToxB-homolog). Sequence analysis to validate the identity of the amplified genes was followed, and ToxA amplicons from a subset of 22 isolates were analyzed to determine its haplotype identity. Ptr isolates from Tunisia were grouped in races 2, 4, 5, and 7, and 44% of the tested isolates did not fit under any known race, and were denoted here as atypical. These atypical isolates induced the same symptoms as race 7 isolates, extensive necrosis, and chlorosis on susceptible genotypes, but lacked the ToxA gene. ToxA is the only identified necrosis-inducing effector in Ptr, and was amplified in 51% of tested isolates, and shared identical sequence to previously identified haplotype (H15). ToxB and its homolog toxb were present in 97% and 93% of tested isolates, respectively. Ptr in Tunisia lacked Ptr ToxC activity, and none of the tested isolates induced the specific symptoms of that effector. Race 7 and the atypical isolates dominated the Tunisian Ptr population, while races 2, 4, and 5 were found at low percentages. In conclusion, ToxB and its homolog were the most dominant genes in Ptr from Tunisia, and the majority of the isolates induced necrosis and chlorosis on Ptr ToxA and Ptr ToxB susceptible wheat genotypes. However, only about half of that necrosis can be attributed to ToxA presence, this result necessitates further research to investigate the prevalence of additional necrotic effector(s). Terminology: in this paper, Pyrenophora tritici-repentis abbreviated as Ptr, the effectors are referred to by Ptr ToxA, Ptr ToxB and Ptr ToxC, and the genes coding for them are written in italic as ToxA, ToxB, and ToxC, respectively.

Expression Analysis of Pyrenophora teres f. maculata-Responsive Loci in Hordeum vulgare

Abstract Pyrenophora teres f. maculata is the causal agent of barley spot form net blotch (SFNB), a major stubble-borne disease in many barley-growing areas worldwide. In plants, the Nucleotide-Binding Site-Leucine-Rich Repeat (NBS-LRR) gene family functions in immunity against a variety of pathogens and pests. From a pre-established set of NBS-type resistance gene candidates, we have selected three candidate genes, HvNBS10, HvNBS72 and HvNBS85, to analyze their possible involvement in P. teres f. maculata resistance. The studied genes were mapped on chromosomes 5H and 7H. Expression profiles using qRT-PCR, 48 hours after infection by P. teres. f. maculata, revealed that the transcription of all genes acted in the same direction (down-regulation) in both resistant and susceptible cultivars, although they showed a variation in transcript dosage. This result suggests that coordinated transcriptional responses of multiple barley NBS genes would be required to an efficient response against P. teres f. maculata. Moreover, the phylogenetic analysis revealed that the studied barley candidate R genes were characterized by a high homology with the barley Nbs2-Rdg2a gene conferring resistance to the fungus Pyrenophora graminea, suggesting a common origin of P. graminea and P. teres resistance genes in barley, following pathogens evolution. The genes characterized in the present study hold potential in elucidating the molecular pathways and developing novel markers associated with SFNB resistance in barley.

Pauci-immune crescentic glomerulonephritis in the Down's syndrome.

Kidney disease is a rare complication in patients with the Down's syndrome. However, with increased survival, it appears that a growing number of these patients present with glomerulonephritis. Most cases have been reported as case reports and include lesions such as mesangiocapillary glomerulonephritis with hypo-complementemia, crescentic glomerulonephritis with anti-neutrophil cytoplasmic antibodies (ANCA), amyloidosis and immunotactoid glomerulopathy. We report the observation of a 38-year-old man with the Down's syndrome who presented with severe renal failure, proteinuria and microscopic hematuria evolving over two months. There was no history of congenital heart disease or urinary symptoms. Percutaneous renal biopsy revealed fibrous crescents, rupture of Bowman's capsule and peri-glomerular granuloma; there were no deposits on immunofluorescence study. Thoracic computerized tomography scan showed alveolar congestion. The patient tested negative for ANCA. At the time of reporting, the patient is on regular chronic hemodialysis. Our case illustrates a distinct entity that further expands the spectrum of renal disease known to occur in the Down's syndrome. Early detection of the renal disorders may prevent or slow down the progression.

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.

Urinary tract infections following renal transplantation: a single-center experience.

Urinary tract infection (UTI) is the most frequent infectious complication among renal transplant recipients and a frequent cause of bacteremia, sepsis and acute graft failure. To evaluate the incidence, risk factors, type of pathogens and long-term effect of UTIs on graft and patient survivals in our center, we performed a retrospective cohort study reviewing the medical records of patients who received a renal transplant at our center from June 1986 to December 2009, excluding patients who lost their grafts in the first month due to arterial or veins thrombosis and acute antibody-mediated rejection. We studied 393 kidney-transplanted recipients; at least one UTI occurred in 221 (53.69%) patients during the follow-up period. The most frequent pathogens isolated in urine culture were Escherichia coli (n = 39, 18.4%) and Klebsiella pneumonia (n = 31, 14.6%). When patients with UTIs were compared with those without UTIs, female gender and use of mycophenolate mofetil or azathioprine seemed to be risk factors for UTIs on univariate analysis. However, female gender was the only independent risk factor on multivariate analysis RR = 1.964 (1.202-3.207), P = 0.007. This study confirmed that UTIs remain a major problem in renal transplant recipients, and female gender was the only independent risk factor.

Short- and long-term outcomes of kidney donors: a report from Tunisia.

Kidney transplantation remains the best treatment option of end-stage renal disease. Kidney donations are of particular interest with the currently increasing practice of living-donor transplantation. The purpose of this study was to analyze retrospectively the general health status as well as renal and cardiovascular consequences of living-related kidney donation. A total of 549 living-related kidney donors had donated their kidneys between 1986 and 2007. We attempted to contact all donors to determine short- and long-term outcome following kidney donation. All kidney donors who responded underwent detailed clinical and biochemical evaluation. The data were compared with age-matched health tables of the Tunisian general population. In all, 284 donors (52%) had a complete evaluation. They included 117 men and 167 women with a mean age of 42 ± 12 years. The major peri-operative complications that occurred in these donors included four cases of pneumothorax, six cases of surgical site infection, one case of phlebitis and one case of pulmonary embolism. None of the study cases died. The median length of hospital stay after donor nephrectomy was 6.5 days (range: 3-28 days). The median follow-up period was eight years. The mean creatinine clearance after donation was 90.4 ± 25 mL/min in men and 81.5 ± 27.2 mL/min in women. Proteinuria was >300 mg/24 h in 17 cases (5.9%). Fifty-eight (20.4%) donors became hypertensive and 19.6% of the men and 37.2% of the women became obese. Diabetes mellitus developed in 24 (8.4%), and was more common in patients who had significant weight gain. Our study suggests that kidney donors have minimal adverse effects on overall health status. Regular follow-up identifies at-risk populations and potentially modifiable factors. Creation of a national registry of living donors and their monitoring are an absolute necessity.

[Acute tubular necrosis in kidney transplantation]. / La nécrose tubulaire aiguë en transplantation rénale.

BACKGROUND: The acute tubular necrosis (ATN) is common after kidney transplantation. Acute tubular necrosis (ATN) is multifactorial and represents one of the main causes of the delayed graft function. Its impact on graft and patients survival is documented. AIMS: To study the prevalence of the ATN in kidney transplanted patients, the acute rejection rate and their impact on the graft and the patient survival. METHODS: We retrospectively studied the frequency of ATN, its causes and its impact on patient and graft survival in 255 kidney transplanted patients between 1986-2006. RESULTS: Thirty-nine patients had ATN (15.29%). They are 25 men and 14 women with mean age of 30.1 ± 12.6 years (8-61) followed for an average of 98 ± 61.76 months. The majority was treated by hemodialysis (79.48%) and half of them were transplanted from kidney of deceased donor. All patients received anti lymphocyte serum and the majority anticalcineurins (69.23%). The outcome was favorable in 26 patients (66.66%) with recovery of diuresis and normalization of renal function after 6 weeks on average. An acute rejection was diagnosed in 21 patients (53.48%). The mean creatinine at 1, 5 and 10 years was 135.3, 159.9 and 121.4 µmol / l. Eight patients had creatinine ² 130 µmol / l at 10 years. Ten patients died from infectious and cardiovascular causes. By comparing the 2 groups ATN + and ATN - we found a statistically significant correlation between ATN and cold ischemia (10 ± 10.9 vs 1.2 ± 4.7 hours, p <0.0001) and the interval between the start of dialysis and transplantation (42.18 ± 38.44 vs. 31.1 ± 25.2 months, p= 0.02). No statistical correlation was found between the ATN and gender, age of recipient and donor, warm ischemia, acute rejection, chronic rejection and graft and patient survival at 1, 5 and 10 years. CONCLUSION: The ATN is more common among transplanted patients from deceased donors. It had good evolution in the majority of cases and it's correlated to cold ischemia and duration of dialysis. Finally, it has no impact on patients and graft survival.

[Association of post-transplant lymphoproliferative disease and visceral leishmaniasis after kidney transplantation]. / Association d'un syndrome lymphoprolifératif et d'une leishmaniose viscérale après transplantation rénale.

Malignancies and opportunistic infections are frequently observed after solid-organ transplantation. Their occurrence strongly affects recipient survival. We report the case of a 29-year-old Tunisian kidney-recipient who was diagnosed simultaneously with post-transplant lymphoproliferative disease (PTLD) and visceral leishmaniasis (VL). Withdrawal of immunosuppressive therapy together with antiparasitic treatment using liposomal amphotericin B, and anti-CD20 antibodies medication resulted in cure of leishmaniasis and remission from PTLD. This case is of clinical interest because of the uncommon association of VL with PTLD after solid organ transplantation. It is also original by the favourable outcome of VL and PTLD, both known as life-threatening diseases. Also, it illustrates the predisposing role of immunosuppressive therapy in occurrence of opportunistic infections and malignancies after solid organ transplantation.

The role of generics in kidney transplant: mycophenolate mofetil 500 versus mycophenolate: 2-year results.

OBJECTIVES: The introduction of mycophenolate mofetil has proven itself effective in preventing acute rejection in renal transplant recipients. However, this cost is ineffective with countries with a limited income. This study sought to compare the clinical and therapeutic profiles of a generic formulation with mycophenolate mofetil. MATERIALS AND METHODS: This 2-year, single-center, prospective, randomized, open-label study investigated the efficacy and safety of a new mycophenolate mofetil generic formulation compared with mycophenolate renal transplant recipients. The study divided patients in 2 groups: 8 patients in G1 received mycophenolate mofetil 500 and 10 patients in G2 received mycophenolate. Their demographics were similar: mean age, 36.6±7.1 and 33.3±11.7 years; sex M/F: 2/6 and 5/5; mean donor age, 42.6±11.1 and 43.6±13.9 years; mean HLA mismatches, 2.7±1.2 and 3.3±1.5; deceased donors, 25% and 20%; and warm ischemia time, 40.2±11.9 and 38.7±10.5 minutes. All patients received 2 g daily of mycophenolate mofetil 500 or mycophenolate with initial dosage of 0.1 mg/kg/d and prednisolone. RESULTS: One patient of 7 in the mycophenolate mofetil group and 4 of 6 in the mycophenolate group had 1 episode of acute tubular necrosis, and 1 patient in each group had an acute rejection with no significant differences between the groups. The area under the curve of the mycophenolate mofetil did not show any difference between the 2 groups. The values of serum creatinine were also comparable. Patient survival rate at 6, 12, and 24 months was 100% in the groups. The frequencies of digestive and hematologic adverse effects were comparable in the groups with no significant differences. CONCLUSIONS: Use of mycophenolate mofetil 500 provided safe and effective immunosuppressive therapy compared with mycophenolate. However, as the duration of the study was short, these results need to be confirmed in a long-term study.

[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.

[Treatment of uremic patients by automated peritoneal dialysis: study of 78 cases]. / Prise en charge des patients urémiques en dialyse péritonéale automatisée : a propos de 78 cas.

BACKGROUND: Automated peritoneal dialysis has been increasingly used in recent years. The quality of life is improved in patients on automated peritoneal dialysis with more time for work, family and social activities compared to patients on continuous ambulatory peritoneal dialysis. AIM: We report our experience concerning patients on continuous ambulatory peritoneal dialysis. METHODS: From July 1997 to June 2003, we review retrospectively 78 patients with chronic renal failure treated by automated peritoneal dialysis. Tenckhoff catheter was used for all patients with 1 cuff in 39 cases (35.5%) and 2 cuffs in 71 cases (64.5%). RESULTS: There were 46 males and 32 females. Their mean age was 38.6 +/- 14.5 years. Their main nephropathies were glomerular in 23 patients (29.%), diabetic in 20 patients (25.6%) and vascular in 19 patients (24.4%). Among the 78 patients, 61 (78.2%) were autonomous while 17 (21.8%) were assisted by a member of their family. The mean period of therapy was 25.5 months (3 to 61 months). Peritonitis was the main complication, it was observed in 45 cases after a mean delay of 17 months (1 to 38 months). The mean rate of peritonitis was 36.5 months/patient. Their etiology was identified in 21 (46.7%) cases (8 septic manipulations of catheter and 13 tunnel infections). The principal organism isolated in peritoneal fluid were 18 gram-positive cocci (13 staphylococcus aureus, 4 coagulase-negative staphylococci, 1 streptococcus) and 10 gram-negative bacilli. The outcome of peritonitis was favourable in 39 cases (86.7%). The actuarial technique survival at 1, 3 and 5 years was respectively 94.6%, 80.1% et 49.3%. The actuarial patient survival at 1, 3 and 5 years was respectively 93.3%, 76.8% et 52.2%. At the end of the study, 43 patients (56.4%) left the automated peritoneal dialysis program: 22 (28.2%) were shifted to hemodialysis, 15 (19.3%) died, 6 (7.7%) were transplanted and 1 patient (1.3%) was shifted to continuous ambulatory peritoneal dialysis. CONCLUSION: Our experience concerning automated peritoneal dialysis is recent with a small number of patients. Our results were acceptable and we have to encourage and extend automated peritoneal dialysis to the most new patients with end-stage renal failure.