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Biomedical subjects

M Hourmant

Publications and source records attributed to M Hourmant.

At least 19 recordsLinked to original sources
PubMed2006

Late ureteral stenosis following renal transplantation: risk factors and impact on patient and graft survival.

The aim of this retrospective study of a cohort of 1787 consecutive kidney transplantations was to analyze the risk factors associated with the occurrence of ureteral stenosis and the impact of ureteral stenosis on graft and patient survival. Between January 1990 and December 2002, 1787 renal transplantations were performed at our center. Only stenosis observed after the first month, were considered. Among the parameters studied were: donor age and serum creatinine before procurement; recipient age, cold ischemia time, delayed graft function (DGF), number of arteries and the presence of a double J stent. The follow-up parameters were the number and timing of acute rejection episodes, cytomegalovirus (CMV) infection, acute pyelonephritis, renal function and death. Ureteral stenosis occurred in 4.1% of patients and was correlated with donor age > 65 years (p = 0.001), kidneys with more than 2 arteries (p = 0.009) and DGF (p = 0.016). Ureteral stenosis did not affect 10-year patient and graft survival rates, which were respectively 90% and 64% for the stenosis group, 86% and 63% for the no-stenosis group (p = NS). These data suggest an important role for donor age, number of renal arteries and DGF for the occurrence of ureteral stenosis following renal transplantation.

Adult↗
PubMed2005

A prospective longitudinal study of BK virus infection in 104 renal transplant recipients.

BK virus (BKV) infection during the first year after renal transplantation was studied prospectively in 104 unselected consecutive patients. Viral DNA in urine (DNAuria) and plasma (DNAemia) samples was detected and quantified by real-time PCR. The noncoding control region (NCCR) of BKV isolates was sequenced. DNAuria and DNAemia occurred in 57% and 29% of patients, respectively. Three groups were defined, uninfected patients (group 1, n=45), patients with DNAuria (group 2, n=29) and patients with positive DNAemia (group 3, n=30). Active infection started within the first 3 months in 80% of patients. Cold ischemia duration over 24 h and the administration of tacrolimus were identified as significant risks factors for DNAuria, whereas it remains more frequently negative in patients receiving cyclosporine A. The risk for positive DNAemia was higher in patients with DNAuria (notably for viral load (VL)>4 log/mL) or treated with tacrolimus. No relationship was found with genetic variability in the NCCR sequence. Our data highlight the high frequency of active BKV infection after renal transplantation. Although high VL was detected in some patients, none developed a BKV nephropathy. A prospective follow-up of the whole population during the first year post renal transplantation is thus not useful to predict BKV disease.

BK Virus↗
PubMed2001

[Viruses involved in allograft recipients'cutaneous carcinomas].

BACKGROUND: Cutaneous carcinomas are frequent in renal allograft recipients. Their treatment can be difficult especially in cases of multiple carcinomas. The aim of this study was to determine whether human papillomavirus are more frequent in patients group with multiple cutaneous carcinomas and whether other viruses such as Epstein-Barr virus, cytomegalovirus, and herpes simplex might be associated in this kind of tumour. PATIENTS AND METHODS: Forty-three patients were included. Twenty-two had a single carcinoma (group 1) and 21 had multiple cutaneous carcinomas (group 2). Histologic analysis and in situ hybridization were used to search for Epstein-Barr virus, human papillomavirus, herpes simplex virus and cytomegalovirus latency genes. RESULTS: In both groups, epidermoid carcinomas were more frequent than basal cell carcinomas and delay between graft and first carcinoma was similar (5 years). In situ hybridization was more often positive in group 2 (41/50) than in group 1 (13/22). Human papillomavirus DNA was detected more frequently in the group with multiple carcinomas (26/50) than in the group with a single carcinoma (6/22). Moreover, cytomegalovirus was more frequent in group 2. CONCLUSION: This study shows a higher prevalence of human papillomavirus DNA in the carcinomas of the multiple carcinoma population. Moreover, for the first time, cytomegalovirus DNA was detected in carcinomas of renal allograft recipients with a higher frequency in the patients with multiple carcinomas.

Adult↗
PubMed2000

Low incidence of kidney rejection after simultaneous kidney-pancreas transplantation after antithymocyte globulin induction and in the absence of corticosteroids: results of a prospective pilot study in 28 consecutive cases.

BACKGROUND: Recipients of simultaneous kidney-pancreas transplantation receive a combination of polyclonal antithymocyte globulin (ATG), cyclosporin or tacrolimus, mycophenolate mofetil (MMF) and corticosteroids (Cs). To avoid the side effects and adverse events associated with Cs, we investigated a new immunosuppressive regimen without Cs after simultaneous kidney-pancreas transplantation. METHODS: A total of 28 consecutive patients who underwent simultaneous kidney-pancreas transplantation were included in this study. All patients received ATG, cyclosporin, and MMF. RESULTS: All patients but one tolerated the ATG course well. MMF was definitively discontinued in three patients because of leukopenia. Cytomegalovirus infection was diagnosed in eight patients (28.5%). Only two patients (7%) required an antirejection treatment. Patient, kidney, and pancreas survival is currently 96.4, 96.4, and 75%, respectively. CONCLUSIONS: The combination of ATG, cyclosporin, and MMF, without Cs, was well tolerated. The unexpectedly low (7%) incidence of acute kidney rejection observed suggests that Cs may partially interfere with the immunosuppressive effect of ATG.

Adolescent↗
PubMed2000

A global appraisal of immunodominant CD8 T cell responses to Epstein-Barr virus and cytomegalovirus by bulk screening.

Knowledge of the immunodominant responses to Epstein-Barr Virus (EBV) and human cytomegalovirus (HCMV) should help to generate cytotoxic T cell lines to these herpesviruses. Here we report on the analysis of CD8 T cell responses to EBV and HCMV in the blood of kidney transplant recipients undergoing viral reactivation (n = 16) and in healthy virus carriers (n = 10). We used a transient COS transfection assay that permits semi-quantitative estimation of CD8+ T cell responses against a larger number of HLA/viral protein combinations within polyclonal T cell lines and thus allows a rapid identification of major epitopes. From the comparison of these responses to those that we previously described in the synovial fluid of patients suffering from various forms of chronic arthritis (n = 32), it appears that EBV-specific T cells are mainly directed against a restricted set of immunodominant epitopes, primarily generated during the early lytic cycle and that both IE1 and pp65 are targets of the anti-HCMV response. We suggest that this method could be generally applied to the rapid identification of immunodominant T cell epitopes in viral and tumor immunity, and could help selecting HLA-peptide complexes that could be used to detect and sort specific T cell populations.

Amino Acid Sequence↗
PubMed2000

Prevention of acute rejection with antithymocyte globulin, avoiding corticosteroids, and delaying cyclosporin after renal transplantation.

BACKGROUND: Despite their well-known side-effects, corticosteroids (Cs) are currently used after kidney transplantation. Avoidance of Cs may improve patient quality of life and eventual long-term survival. We report on a regimen using antithymocyte globulin (ATG) and mycophenolate mofetil (MMF) for induction, and cyclosporin (CsA) plus MMF for maintenance treatment of recipients of primary kidney transplantation. METHODS: We studied 11 consecutive, non-sensitized renal transplant patients (nine cadaver and two living donors). Initial immunosuppression consisted of ATG (1.5 mg/kg/day, i.v.) given for 10 days and MMF (1.0 g/b.i.d.). CsA (8 mg/kg, in two divided doses) was started on post-operative day 11. Cs were only allowed in the case of MMF discontinuation, for the treatment of acute rejection, and in the event of recurrence of the primary glomerulonephritis. RESULTS: All patients completed the entire 10-day ATG course. Main side-effects included fever (>38 degrees C) and serum sickness, observed in 73 and 27% of the patients respectively. The incidence of acute rejection was 27% (three of 11 patients). In two patients with acute rejection, serum sickness was concomitantly diagnosed and renal histology was partially compatible with immune-complex disease. The remaining patient had two episodes of low-grade rejection. All rejection episodes were rapidly reversed. Two patients (18%) were treated with ganciclovir for cytomegalovirus (CMV) infection. Two patients (18%) are currently receiving Cs for recurrence of the native glomerulonephritis and two rejection episodes respectively. All patients are currently alive with functioning kidneys (average follow-up of 8.4 months; average creatinine level of 128 micromol/l). CONCLUSION: This pilot study suggests that ATG induction in combination with MMF and delayed introduction of CsA, in the absence of Cs, is not well tolerated in recipients of kidney transplants. An earlier introduction of calcineurin inhibitors and/or a shorter course of ATG may reduce the incidence of fever and serum sickness secondary to ATG.

Acute Disease↗
PubMed1999

[Renal ischemia reperfusion syndrome].

Ischemia reperfusion injury is an uncommon kind of inflammation. Oxygen deprivation is followed by cellular dysfunction, reversible or not and mainly tubular. Ischemia initiates and amplifies the fundamental events of reperfusion injury, that are going to occur after oxygen reintroduction. Reperfusion is characterized by the production of oxygen reactive species, endothelial activation, endothelial release of chemoattractants, chemokines and cytokines, expression of adhesion molecules, that are going to mediate the recruitment and activation of circulating leucocytes, later responsible for the main lesions of reperfusion injury. Studies in kidney transplantation have brought evidence that the fibrotic healing of reperfusion injury have long term and significant consequences on kidney function.

Cell Hypoxia↗
PubMed1998

Effect of long-term immunosuppression in kidney-graft recipients on cancer incidence: randomised comparison of two cyclosporin regimens.

BACKGROUND: Long-term administration of cyclosporin carries a risk of renal toxicity, and immunosuppressants are associated with an increased rate of malignant disorders. We undertook an open randomised study of the risks and benefits of two long-term maintenance regimens of cyclosporin in kidney-allograft recipients. The primary endpoint was graft function; secondary endpoints were survival and occurrence of cancer and rejection. METHODS: 231 recipients of a first allograft with at most one previous rejection episode were randomised 1 year after transplantation. Most were receiving cyclosporin and azathioprine. One group received cyclosporin doses adjusted to yield trough blood concentrations of 75-125 ng/mL (low-dose group); the second received doses that yielded trough concentrations of 150-250 ng/mL (normal-dose group). Analysis was by intention to treat. FINDINGS: At 66 months' follow-up, the low-dose and normal-dose groups were similar in mean serum creatinine (182 [SD 160] vs 184 [157] micromol/L; p=0.9) and mean creatinine clearance (47.5 [25.1] vs 45.3 (22.5] mL/min; p=0.6). Nine of 116 patients in the low-dose group and one of 115 in the normal-dose group had symptoms of rejection (p<0.02). There was no difference between the low-dose and normal-dose groups in survival (95 vs 92%; p=0.7) or graft survival (89 vs 82%; p=0.17) at 6 years. 60 patients developed cancers, 37 in the normal-dose group and 23 in the low-dose group (p<0.034); 66% were skin cancers (26 vs 17; p<0.05). INTERPRETATION: We found no evidence that halving of trough blood cyclosporin concentrations significantly changes graft function or graft survival. The low-dose regimen was associated with fewer malignant disorders but more frequent rejection. The design of long-term maintenance protocols for transplant recipients based on powerful immunosuppressant combinations should take these potential risks into account.

Adolescent↗
PubMed1998

Delayed graft function of more than six days strongly decreases long-term survival of transplanted kidneys.

BACKGROUND: We reviewed 843 first cadaver kidney transplants carried out consecutively at our center to examine the effect on long-term graft survival of the duration of delayed graft function (DGF), defined as the time taken for the kidney to attain the threshold of a Cockcroft calculated creatinine clearance (cCCr) > or = 10 ml/min. METHODS: Using a multivariate Cox survival analysis we evaluated the consequences of DGF on allograft survival, and then by regression analysis identified the factors contributing to the occurrence of DGF. Finally, using a Kaplan Meier analysis we compared the profiles of graft failure according to the duration of DGF. RESULTS: Defining DGF in terms of cCCr rather than necessity for dialysis after transplantation allowed better prediction of long-term graft loss. Indeed, patients with a Cockcroft-based DGF > six days who did not require dialysis (12%) had a significantly poorer long-term graft outcome than those with a DGF < or = six days. Furthermore, we showed that a DGF of six days could be taken as a cut-off point that marked a significant difference in the long-term graft survival rate (P < 0.0001). Surprisingly, further extension of the duration of DGF > six days was not associated with further worsening of graft survival (except in DGF > 30 days). CONCLUSION: Our results suggest a threshold effect in the lesions that ultimately results in long-term functional deficiency. In addition, we show that the need for dialysis is not an adequate criterium for DGF in terms of long-term outcome prediction.

Adolescent↗
PubMed1998

Randomized comparison of triple therapy and antithymocyte globulin induction treatment after simultaneous pancreas-kidney transplantation.

BACKGROUND: The incidence of acute rejection is considered to be higher after simultaneous pancreas-kidney (SPK) transplantation as compared to renal transplant alone. Therefore, the majority of SPK transplant recipients commonly receive a combination of cyclosporine (CsA) or tracolimus, and azathioprine or mycophenolic mofetyl, corticosteroids and/or antilymphocyte preparations. This study was designed to compare two immunosuppressive protocols for the prevention of acute rejection in patients undergoing SPK transplantation. The primary end-point was the incidence of acute rejection during the first 12 months after transplantation METHODS: Fifty patients with type-I insulin-dependent diabetes and chronic renal failure were randomized to receive a triple drug immunosuppressive regimen including CsA, azathioprine and corticosteroids (N = 25), or the quadruple sequential combination of rabbit antithymocyte globulin (ATG) given for 10 days, azathioprine, corticosteroids and delayed CsA (N = 25). Maintenance immunosuppression (CsA and azathioprine, without corticosteroids) was similar in both arms. RESULTS: The average follow-up was 36 months in both groups (range 9 to 60 months). No patient was excluded from the study. Although the percentage of patients with adverse events was higher in the ATG group (80 vs. 40%, P < 0.01), none of them resulted in premature discontinuation of the drug. Patients receiving ATG experienced a lower incidence (36% vs. 76%, P < 0.01) and number (13 vs. 29, P < 0.05) of acute renal rejection episodes. However, no difference was observed in patient, pancreas and kidney survival rates between groups. No case of isolated pancreas rejection was observed. CONCLUSIONS: The quadruple sequential combination ATG, azathioprine, corticosteroid and CsA significantly reduced the one year incidence of acute renal rejection after SPK transplantation, compared to a triple immunosuppressive regimen.

Adrenal Cortex Hormones↗
PubMed1997

Frequency of mucosal HPV DNA detection (types 6/11, 16/18, 31/35/51) in skin lesions of renal transplant patients.

Human papillomaviruses (HPV) probably play a role in the development of skin cancer in renal transplant recipients. Since some mucosal HPV are strongly related to cervical cancer, we compared the frequency of HPV DNA detection (mucosal types 6/11, 16/18, and 31/33/51) in skin cancer of renal transplant recipients (21 lesions) with that in normal subjects without immunodeficiency (21 lesions) and studied the frequency of these same HPV in benign lesions of renal transplant recipients (34 lesions) and normal subjects (30 lesions). An in situ hybridization technique employing cold biotin probes was used. HPV DNA was not significantly (P = 0.095) more frequent in malignant skin cancer in renal transplant recipients (42.9%) than in normal subjects (19.04%), but was significantly more frequent in benign lesions in renal transplant recipients (32.4%) than in controls (10%; P < 0.05). These results on a limited number of skin lesions do not allow one to confirm the predominant role of mucosal HPV in the development of skin cancer in renal transplant recipients. HPV interaction with other factors related to the immunosuppressive state may play a role.

Adult↗
PubMed1997

[Outcome of nephrogenic metaplasia of the bladder in kidney transplant recipients].

OBJECTIVES: To evaluate the risk of recurrence and malignant degeneration of vesical nephrogenic metaplasia in renal transplant recipients. MATERIAL AND METHODS: Fourteen patients with known nephrogenic metaplasia were systematically followed. Vesical biopsies were performed with a resector, stained with eosin haemalun saffron, analysed and compared to initial results. Labelling by anti-EBV and anti-CMV monoclonal antibodies was performed in 5 cases of intense inflammatory reactions. RESULTS: All patients were males, with a median age of 39 years. Nephrogenic metaplasia had been diagnosed 7 to 80 months after renal transplantation (median = 37.8). Twelve patients were reviewed 5 to 116 months after the initial diagnosis (median = 52). Relapse was observed in 83% of cases, but without any malignant degeneration. CONCLUSION: Nephrogenic metaplasia is therefore a benign recurrent disease. The importance of the initial blood supply and fibrosis in the case of recurrence suggest a disorder of the blood supply, probably traumatic in origin. Only symptomatic patients are currently followed.

Adolescent↗
PubMed1996

A randomized multicenter trial comparing leukocyte function-associated antigen-1 monoclonal antibody with rabbit antithymocyte globulin as induction treatment in first kidney transplantations.

Adhesion molecules are involved in several steps in the immune response: leukocyte adhesion to the endothelium, transendothelial migration, cooperation between immunocompetent cells, and cytotoxicity. Leukocyte function-associated antigen-1 plays a central role among adhesion molecules. In a multicenter randomized open trial, we compared a monoclonal antibody directed against the alpha chain of LFA-1 (Oduli-momab; IMTIX/Pasteur Mérieux Sérums et Vaccins) with rabbit antithymocyte globulin (rATG; IMTIX/Pasteur Mérieux Sérums et Vaccins), as part of a quadruple sequential protocol in 101 patients receiving a first kidney transplant. Clinical tolerance of anti-LFA-1 mAb was better than that of rATG. Short-term rejection rates (< 15 days) were not significantly different (15% and 16% for anti-LFA-1 mAb and rATG, respectively). However, 11% of the anti-LFA-1 mAb patients experienced rejection during the first 10 days of the treatment course compared with none of the patients treated with rATG. The incidence and severity of acute rejection in the first 3 months was not significantly different between groups. Of the LFA-1 and rATG patients, 96% and 92% of the grafts, respectively, were functioning at 12 months. The incidence and severity of infection, whatever the origin, were comparable in both groups. In addition, it was observed that fewer patients required posttransplantation dialysis in the anti-LFA-1 mAb group (19%, vs. 35% for rATG), although the difference was not statistically significant. Altogether, the beneficial action of this monoclonal antibody on short-term renal function recovery makes it a useful tool in the management of renal patients undergoing kidney transplantation.

Acute Disease↗
PubMed1996

Anti-CD4 MoAb therapy in kidney transplantation--a pilot study in early prophylaxis of rejection.

B-F5, a mouse IgG1 anti-CD4 MoAb, was used in recipients of a first cadaveric kidney allograft. Eighteen patients received 30 mg/day MoAb with a quadruple sequential therapy. All but one kidney were functioning at 6 months, with a mean serum creatinine of 153 micromol/L. However, 50% of the patients had an acute rejection episode within the first three months, and most of the early episodes (i.e., < 1 month) occurred in patients with low levels of circulating MoAb. The biological analysis showed a strong depleting effect on the CD4+ cell counts, a saturation by the MoAb of the remaining circulating CD4+ cells, and no detectable immunization against B-F5. Although the biological parameters indicate an action of B-F5 in vivo, the clinical data associated with poor MoAb bioavailability suggest the need for an improved pharmacokinetic behavior of the MoAb to determine its use for prophylaxis of early rejection.

Adult↗
PubMed1996

A dose-searching trial of an anti-LFA1 monoclonal antibody in first kidney transplant recipients.

25.3, a mouse IgG1 monoclonal antibody (MoAb), directed at the alpha chain of the LFA1 molecule (CD11a) has been used in prophylaxis of rejection in recipients of cadaveric kidney graft. Promising clinical results have been obtained for both tolerance and efficacy [1]. The aim of this trial was to determine the optimal dosage, base on a pharmacokinetic-pharmacodynamic analysis of the data obtained from the 15 patients included in this dose-searching study. Biological parameters, such as circulating levels and functional inhibition (as detected in an adhesion assay of patient lymphocytes), were measured during and after treatment. A Hill relation was calculated between the effect and the concentration measured and led us to select a 15 mg/day dose for further clinical trials, with a loading dose of 30 mg. An additional group receiving this protocol was submitted to the same calculation, and the results from this last group were in agreement with this previous analysis.

Adolescent↗