Renal transplantation in human immunodeficiency virus-infected recipients: a case-control study from the Brazilian experience.

BACKGROUND: Highly active antiretroviral therapy has turned human immunodeficiency virus (HIV)-infected patients with end-stage renal disease into suitable candidates for renal transplantation. We present the Brazilian experience with kidney transplantation in HIV-infected recipients observed in a multicenter study. METHODS: HIV-infected kidney transplant recipients and matched controls were evaluated for the incidence of delayed graft function (DGF), acute rejection (AR), infections, graft function, and survival of patients and renal grafts. RESULTS: Fifty-three HIV-infected recipients and 106 controls were enrolled. Baseline characteristics were similar, but a higher frequency of pre-transplant positivity for hepatitis C virus and cytomegalovirus infections was found in the HIV group. Immunosuppressive regimens did not differ, but a trend was observed toward lower use of anti-thymocyte globulin in the group of HIV-infected recipients (P = 0.079). The HIV-positive recipient group presented a higher incidence of treated AR (P = 0.036) and DGF (P = 0.044). Chronic Kidney Disease Epidemiology Collaboration estimated that glomerular filtration rate was similar at 6 months (P = 0.374) and at 12 months (P = 0.957). The median number of infections per patient was higher in the HIV-infected group (P = 0.018). The 1-year patient survival (P < 0.001) and graft survival (P = 0.004) were lower, but acceptable, in the group of HIV-infected patients. CONCLUSIONS: In the Brazilian experience, despite somewhat inferior outcomes, kidney transplantation is an adequate therapy for selected HIV-infected recipients.

Outcomes in obese kidney transplant recipients.

BACKGROUND: Kidney transplantation (KT) in obese patients is controversial. The present study aimed to evaluate patient and graft survival and post-transplantation complications between obese and nonobese recipients. METHODS: Patients (n = 3,054) receiving a KT from 1998 to 2008 were divided according to body mass index (BMI) into 3 groups for analysis: group I: BMI <30 kg/m(2) (nonobese); group II: ≥30-34.9 kg/m(2) (class I obese); and group III: ≥35 kg/m(2) (class II and III obese). RESULTS: Mean BMIs were: group I (n = 2,822): 22.6 ± 3.3 kg/m(2); group II (n = 185): 31.9 ± 1.3 kg/m(2); and group III (n = 47): 36.8 ± 1.7 kg/m(2). There were no differences among the 3 groups in patient demographic variables regarding race, sex, or organ source. One-year (I, 98%; II, 98%; III, 95%) and 5-year (I, 90%; II, 92%; III, 89%) patient survival rates were similar among groups. Graft survival rates at 1 year were 96% for groups I and II and 91.5% for group III. Five-year graft survivals were: I, 81%; II, 96%; and III, 79%. The most common cause of graft loss was death, and the main cause of death was infection in all groups. Obese patients were more likely to experience wound dehiscence (I, 1.9%; II, 7.6%; III, 19.1%; P < .001), develop new-onset diabetes after transplantation (NODAT; I, 16.2%; II, 27%; III, 36%; P < .001), and have a prolonged length of hospital stay (I, 11.3 ± 11.4 d; II, 14.5 ± 14.3 d; III, 15.9 ± 16.7 d; P < .001). CONCLUSIONS: Obese recipients demonstrated outcomes similar to nonobese patients regarding patient and graft survival. However, they had higher rates of prolonged length of hospital stay, wound dehiscence, and NODAT.

Late presentation of Alport posttransplantation anti-glomerular basement membrane disease.

We describe a female patient with Alport disease who developed antiglomerular basement membrane nephritis late after kidney transplantation during the treatment of an acute bacterial pyelonephritis and discuss the potential role of the infection as a trigger for the development of this nephritis.

Risk factors associated with graft loss and patient survival after kidney transplantation.

OBJECTIVE: To evaluate the influence of traditional risk factors on major kidney transplantation outcome. PATIENTS AND METHODS: Data from kidney transplantation procedures performed between 2003 and 2006 were retrospectively analyzed for the influence of traditional risk factors on transplantation outcome. Of 2364 transplants, 67% were from living donors, 27% were from donors who met standard criteria, and 6% were from donor who met expanded criteria. Two hundred thirty-nine procedures (10%) were performed in pediatric patients. Immunosuppression was selected on the basis of subgroup population. RESULTS: At 1 year posttransplantation, cumulative freedom from a treated acute rejection episode (ARE) was 76.7%, with no difference between black vs nonblack recipients (75.0% vs 73.4%; P = .79). At 2 years, survival for patients (95.3% vs 88.3% vs 82.1%; P < .001) and grafts 92.3% vs 80.3% vs 70.9%; P < .001) was better in recipients of living donor grafts compared with donors who met standard or expanded criteria, respectively. Moreover, graft survival was poorer in black vs nonblack patients (83.6% vs 88.7%; P < .05) because of high mortality (13% vs 7%; P<.001). Risk factors associated with death included cadaveric donor organ (odds ratio [OR], 2.4) and black race (OR, 1.8), and risk factors associated with graft loss included cadaveric donor organ (OR, 2.1), extended-criteria criteria donor organ (OR, 2.0), delayed graft function (OR, 1.8), and any ARE (OR, 3.5). At 6 months posttransplantation, risk factors associated with death included cadaveric donor organ (OR, 2.5) or ARE (OR, 2.4), and risk factors associated with graft loss included cadaveric donor organ (OR, 2.0), extended-criteria donor organ (OR, 2.6), ARE (OR, 9.5), and impaired graft function (creatinine concentration >1.5 mg/dL; OR, 2.1). CONCLUSION: Traditional risk factors are still associated with transplantation outcome. Poorer graft survival in black vs nonblack recipients was due to higher mortality rather than graft loss.

Comparison of the biodistribution of free or liposome-entrapped Crotalus durissus terrificus (South American rattlesnake) venom in mice.

The local absorption rate, clearance and tissue distribution of Crotalus durissus terrificus venom, (Cdt) were examined using a two-antibody sandwich ELISA assay. We compared the biodistribution of both free or encapsulated Cdt in mice. Following subcutaneous injection of 10 microg/mouse of free Cdt (0.8 LD50), venom was detected in serum after 15 min, showed its highest level at 30 min (45+/-5 ng/ml) and was cleared from the circulation after 6 h. After 2 h of inoculation, venom was detected in the kidney (57+/-9 ng/g of tissue), spleen (18+/-4 ng/g of tissue) and brain (14+/-6 ng/g of tissue). For both subcutaneous or intravenous injection of free Cdt, venom was firstly detected in the kidney. No Cdt appeared either in the kidney, spleen, brain, or other tissues after subcutaneous inoculation of encapsulated venom even though a higher dose was used, 25 microg/mouse (2 LD50). Venom remained at the site of injection for a period of 1 week. Following intravenous injection of encapsulated venom (5 microg/mouse, 2 LD50), venom was detected in liver and spleen tissues. The biodistribution of encapsulated venom is discussed in relation to the effects of reduction of toxicity and increase of adjuvanticity.

Effect of membrane composition and of co-encapsulation of immunostimulants in a liposome-entrapped crotoxin.

Crotoxin isolated from the venom of Crotalus durissus terrificus (South American rattlesnake) was incorporated into liposomes by the dehydration-rehydration vesicle method using different membrane compositions and the co-encapsulation of immunostimulants. Crotoxin was also encapsulated into liposomes formed from a non-phospholipid amphiphile, a mixture of polyoxyethylene 2-cetyl ether, dicetyl phosphate and cholesterol. The preparations were characterized in relation to stability, toxicity and the protection of mice against whole venom after immunization. All liposome preparations were quite stable, retaining more than 75% of the originally encapsulated crotoxin after 1 week of incubation at physiological temperature. Co-encapsulation with lipopolysaccharide increased the leakage of crotoxin. In contrast, co-encapsulation of the lipid moiety of lipopolysaccharide did not influence the stability of liposomes. Toxicity of liposomes was dependent on membrane composition. Liposomes made with phospholipids that were resistant to phospholipase A(2) activity were less toxic. Mice immunized with three doses of the 1 x LD50 of crotoxin encapsulated into liposomes, and with associated immunostimulants, were protected against challenge with 8 x subcutaneous LD50 of C. durissus terrificus venom. Using the same immunization schedule, liposomes made from a non-phospholipid mixture and without immunostimulants achieved 100% protection.

Immunization with liposome-encapsulated Bothrops jararaca venom.

The venom of Bothrops jararaca (BjV) snake was encapsulated into liposomes. The toxicity and ability of the resultant liposomes to protect mice were evaluated. No acute toxicity was found in mice, when liposomes were subcutaneously injected whereas the same dose of venom emulsified in Freund's adjuvant caused the mice to die. Immunization with the venom containing liposomes and associated immunostimulants, protected 50% of mice after challenge with BjV (4 x LD50). The hemorrhagic activity induced by BjV was reduced after immunization with liposomes associated with immunostimulants, similarly to immunization with BjV emulsified in Freund's adjuvant. However, mice immunized with BjV:Freund's were better protected against the lethal effects of the venom.

Encapsulation of native crotoxin in liposomes: a safe approach for the production of antivenom and vaccination against Crotalus durissus terrificus venom.

Crotoxin, the neurotoxic component of Crotalus durissus terrificus (Cdt) venom that displays phospholipase A2 activity, was successfully encapsulated into dehydration-rehydration vesicles (DRV/crotoxin) and reverse-phase evaporation vesicles (REV/crotoxin) made from sphingomyelin and cholesterol. The encapsulation efficiency of native crotoxin was higher in DRV/crotoxin than in REV/crotoxin. DRV/crotoxin was not toxic when i.v. inoculated in mice at a dose of crotoxin as high as 91 times its L.D50 or when s.c. inoculated at 42 times its LD50. On the other hand, crotoxin released from DRV/crotoxin retained its original toxicity. REV/crotoxin was found to be at least 1.9 times more toxic than DRV/crotoxin. The fact that DRV/crotoxin retained crotoxin more efficiently than REV/crotoxin may account for the difference in acute toxicity between the two preparations. DRV/crotoxin, when s.c. inoculated in mice, induced anti-crotoxin antibodies that protected animals against the lethal effect of Cdt venom. Following immunization with three doses of DRV/crotoxin (3 x 20 micrograms of crotoxin/mouse) and challenge with 8 x LD50 of Cdt venom, 75% of mice were protected. The DRV/crotoxin preparation was compared to crotoxin emulsified in Freund's adjuvant (FCA/crotoxin). DRV/crotoxin was found to be less toxic than FCA/crotoxin, and to induce lower levels of anti-crotoxin antibodies but similar levels of protection when inoculated at high doses (20 or 70 micrograms crotoxin/mouse). When DRV/crotoxin was adsorbed to alum at the time of immunization, it induced antibody and protection levels comparable to those produced by FCA/crotoxin.

Biological activities of venoms from South American snakes.

Standard assay procedures for the characterization of snake venoms, developed by the World Health Organization (WHO) Collaborating Centre for the Control of Antivenoms (CCCA), were used to analyse 33 snake venoms including eight International Reference Venoms for the assessment of lethal, defibrinogenating, procoagulant, haemorrhagic and necrotizing properties. The International Reference Venoms were assayed as part of an International Collaborative Programme for the evaluation of Venoms and Antivenoms; the results showed a close relationship to those obtained by the CCCA. Twenty-five venoms from 13 different species of medically important snakes from South America were assayed as standardized by the WHO-CCCA. Additionally, evaluation of lethal activity by the i.p. and intra cerebroventricular routes, proteolytic effects and venom-induced edema were also determined. Venom yields from captive snakes are also presented. Among the venoms examined, from the subfamily Crotalinae, the members of the genera Bothrops and Lachesis had strong haemorrhagic, proteolytic and edema-inducing activities, whereas all Crotalus durissus species had none. The Elapinae, Micrurus frontalis showed no procoagulant, defibrinogenating, haemorrhagic, necrotizing or proteolytic activities. The results reflect differences among individual samples of the same species and of different geographical regions. The results suggest that there is little or no relationship between the properties of the different venoms and that the determination of one effect cannot predict the value of the others. Therefore, the characterization of the different activities of snake venoms is necessary if toxicity is to be properly evaluated and neutralized.

Immunization of horses with Crotalus durissus Terrificus (South American Rattlesnake) venom: a comparision of four different procedures

A comparative study was carried out on horses immunized with Crotalus durissus terrificus venom using four different inoculation procedures, which included the use Freund's adjuvant, A1(OH)3 and liposomes as adjuvants. The antibody titer was assessed by enzyme linked immunosorbent assay (ELISA) and the neutralizing potency by the neutralizing median effective dose (ED50). The inoculation schedule used in horses to obtain antivenom serum consisted of scinjections of a 7.5 mg venom starting dose in 5.0ml sterile saline emulsified with an equal volume sterile saline at 2-dayintervals. This immunization procedure, based in low doses of antigen (37.5mg/horse) emulsified with Freund's adjuvant, proceduced a more protective andsustained immune response whencompared with other procedures using A1(OH)3 and 5.0 mg/horse in liposome) or high (870.0 mg/horse in A1(OH)3 and 20.0 mg/horse in liposome) antigen doses. The ED50 values evaluated at the end of the procedure were 15.4 *l serum/20 gmouse when antigen was emulsified with Freund's adjuvant; 21.7 * serum/20 g mouse when 870,0 mg antigen/horse was emulsified with A1(OH)3 and 30.0 *l serum/20 g mouse when 50.0 mg antigen/hors was emulsified with a1(OH)3.When antigen was emulsified with liposome, the immune serum was ineffective against the lethal effects of C.d terrificus venom. The inoculation schedule used in horses to obtain hyperimmune serum consisted of reimmunization with sc booster injections of 7.5 mg venom in 5.0 ml sterile saline emulsified with an equal volume of Freund's incomplete adjuvant. One week later, 2.5 mg venom in 12.0 ml sterile saline was inoculated at 2-day intervals.This reimmunization schedule,based on low doses of antigen (15.0 mg/horse) emulsified with Freund's incomplete adjuvant or with saline, produced a protective andsustained immune response, regardless of the initial immunization procedure. The ED50 evaluatedfor each of the animals five days after the reimmunization period was never more than 20 * serum/20 g mouse. The liposome inoculation method employed a membrane-stabilized reverse phase evaporation preparation of sphingomyelin/cholesterol 2.5/1 (w/w) liposomes. This procedure permits incorporation of 1.0 mg protein per mg of phospholipid. This liposome inoculation method , which stimulates a rapid, sustained and protective immune response in mice and rabbits inoculated with both C.d. collineatus and C.d. terrificus, was not effective when horses were immunized with C.

Immunization of horses with Crotalus durissus terrificus (South American rattlesnake) venom. A comparison of four different procedures.

1. A comparative study was carried out on horses immunized with Crotalus durissus terrificus venom using four different inoculation procedures, which included the use of Freund's adjuvant, A1(OH)3 and liposomes as adjuvants. The antibody titer was assessed by enzyme linked immunosorbent assay (ELISA) and the neutralizing potency by the neutralizing median effective dose (ED50). 2. The inoculation schedule used in horses to obtain antivenom serum consisted of sc injections of a 7.5 mg venom starting dose in 5.0 ml sterile saline emulsified with an equal volume of Freund's complete adjuvant. One week later, 7.5 mg venom in 5.0 ml sterile saline emulsified with an equal volume of Freund's incomplete adjuvant was injected. This was followed by three doses of 2.5 mg venom in 12.0 ml sterile saline at 2-day intervals. This immunization procedure, based on low doses of antigen (37.5 mg/horse) emulsified with Freund's adjuvant, produced a more protective and sustained immune response when compared with other procedures using A1(OH)3 or liposome emulsions with either low (50.0 mg/horse in A1(OH)3 and 5.0 mg/horse in liposome) or high (870.0 mg/horse in A1(OH)3 and 20.0 mg/horse in liposome) antigen doses. The ED50 values evaluated at the end of the procedure were 15.4 microliters serum/20 g mouse when antigen was emulsified with Freund's adjuvant; 21.7 microliters serum/20 g mouse when 870.0 mg antigen/horse was emulsified with A1(OH)3 and 30.0 microliters serum/20 g mouse when 50.0 mg antigen/horse was emulsified with A1(OH)3. When antigen was emulsified with liposome, the immune serum was ineffective against the lethal effects of C. d. terrificus venom. 3. The inoculation schedule used in horses to obtain hyperimmune serum consisted of reimmunization with sc booster injections of 7.5 mg venom in 5.0 ml sterile saline emulsified with an equal volume of Freund's incomplete adjuvant. One week later, 2.5 mg venom in 12.0 ml sterile saline was inoculated at 2-day intervals. This reimmunization schedule, based on low doses of antigen (15.0 mg/horse) emulsified with Freund's incomplete adjuvant or with saline, produced a protective and sustained immune response, regardless of the initial immunization procedure. The ED50 evaluated for each of the animals five days after the reimmunization period was never more than 20 microliters serum/20 g mouse. 4. The liposome inoculation method employed a membrane-stabilized reverse phase evaporation preparation of sphingomyelin/cholesterol 2.5/l (w/w) liposomes. This procedure permits incorporation of 1.0 mg protein per mg of phospholipid.(ABSTRACT TRUNCATED AT 400 WORDS)

Protection against the lethal effects of Crotalus durissus terrificus (South American rattlesnake) venom in animals immunized with crotoxin.

Mice and rabbits were immunized against crotoxin (the neurotoxic component isolated from Crotalus durissus terrificus venom) using small amounts of antigen in a water-in-oil emulsion. Following boosting (three times at 21-day intervals) a high titre of antibodies against crotoxin was obtained. Crotoxin immunoglobulin G antibody recognizes whole venom antigen at a level comparable with that of crotoxin antigen, using the ELISA method for antibody detection. The antibodies generated by crotoxin were capable of providing 100% protection against challenge with 11 and 50 i.p. LD50 doses of whole venom in mice. When 100 i.p. LD50 doses of whole venom were injected survival was 77.8%.

Use of liposomes for protective immunisation against Crotalus durissus (tropical rattlesnake) venom.

Crotalus durissus venom has been described as a weak antigen when injected in combination with Freund's complete adjuvant during the course of traditional methods of equine immunisation. Antibody production is slow and unpredictable, with a wide variation in individual responses. In this experimental study, C. durissus venom was incorporated into stabilised sphingomyelin-cholesterol liposomes both in the presence and absence of lipopolysaccharide immunostimulant and injected by both i.v. and s.c. routes into mice and rabbits. A rapid, sustained and protective immune response was obtained following a single injection of these preparations in mice. Antibody levels were estimated using enzyme-linked immunosorbent assay (ELISA), and the protective effect was evaluated by subsequent challenge with a subcutaneous minimum lethal dose of the venom. Results indicated that the immune response was significantly potentiated by the presence of immunostimulant in the venom liposomes. The use of C. durissus venom liposomes should be a useful tool for the immunisation of animals both in experimental and commercial procedures.