A Multicenter Case-control Study of the Effect of Acute Rejection and Cytomegalovirus Infection on Pneumocystis Pneumonia in Solid Organ Transplant Recipients.

BACKGROUND: Pneumocystis pneumonia (PCP) is associated with morbidity and mortality in solid organ transplant (SOT) recipients. In this case-control study, we determined the association between posttransplant PCP and 3 variables: cytomegalovirus (CMV) infection, allograft rejection, and prophylaxis. METHODS: Eight transplant centers participated. For each case (SOT recipient with PCP), 3-5 controls (SOT recipients without PCP) were included. Controls were matched to the cases based on transplant center, type of allograft, and date of transplantation (±6 months). RESULTS: We enrolled 53 cases and 209 controls. Transplant types included kidney (n = 198), heart (n = 30), liver (n = 15), kidney-pancreas (n = 14), and lung (n = 5). PCP occurred beyond 12 months after transplantation in 43 (81.1%) cases. Thirty-four cases (64.1%) required admission to the intensive care unit, and 28 (52.8%) had mechanical ventilation. Allograft failure occurred in 20 (37.7%) cases, and 14 (26.9%) died. No patient developed PCP prophylaxis breakthrough. The proportion of female sex (P = .009), kidney dysfunction (P = .001), cardiac diseases (P = .005), diabetes mellitus (P = .03), allograft rejection (P = .001), CMV infection (P = .001), and severe lymphopenia (P = .001) were significantly higher in cases. In the logistic regression model, CMV infection (adjusted odds ratio [aOR], 4.6 [95% confidence interval {CI}, 2.0-10.5]) and allograft rejection (aOR, 3.0 [95% CI, 1.5-6.1]) significantly increased the likelihood of PCP. CONCLUSIONS: PCP was mostly a late-onset disease occurring after complete course of prophylaxis, particularly among patients with CMV infection or allograft rejection. PCP is associated with significant allograft loss. Extended prophylaxis targeting recipients with allograft rejection or CMV infection may reduce the risk of PCP.

Peritoneal dialysis versus hemodialysis in patients with delayed graft function.

Delayed graft function (DGF) in kidney transplantation affects adverse outcomes. It remains unclear whether the post-transplant dialysis modality alters perioperative or long-term graft outcomes. We performed a retrospective observational quality initiative at two Canadian renal transplant centers, in which DGF occurred in the recipient, necessitating one of peritoneal dialysis (PD) or hemodialysis (HD). There was no difference in baseline factors between patients with post-transplant PD (n = 14) or HD (n = 63). The use of PD was associated with an increased risk of wound infection/leakage (PD 5/14 vs. HD 6/63, p = 0.024), shorter length of hospitalization (13.7 vs. 18.7 d, p = 0.009) and time requiring dialysis post-operatively (6.5 vs 11.0 d, p = 0.043). There were no differences in readmission to hospital within 6 months (4/14 vs. 23/63, p = 0.759), graft loss (0/14 vs. 2/63, p = 1.000) or acute rejection episodes (1/14 vs. 4/63, p = 1.000) at one yr, and GFR did not differ between the PD or HD groups at 30 d (35.7 vs. 33.8 mL/min/m(2), p = 0.731), six months (46.9 vs. 45.5 mL/min/m(2), p = 0.835) or one yr (46.6 vs. 44.5 mL/min/m(2), p = 0.746). Further research is needed to determine which transplant patients are most appropriate to undergo PD catheter removal at the time of transplantation.

Prediabetes: a must to recognise disease state.

UNLABELLED: Prediabetes mellitus (PDM) is defined as a state of abnormal glucose homeostasis in which deficiency or resistance to insulin is the hallmark. PDM precedes the development of overt type 2 DM. It is associated with increased mortality and morbidity and thus fits well with the criteria of a disease condition. Framing PDM as a disease and not a risk or a 'pre' stage for diabetes is needed to facilitate early management. AIM: This review aims therefore to increase awareness of PDM as a disease state. METHODS: To do so, we shall preview guidelines for its diagnosis. Its prevalence and hazards will be then discussed. Finally, we shall elaborate on the current treatment guidelines. RESULT: Enough evidence support the notion that PDM is a curable disease state. CONCLUSIONS: The current recommendations for the treatment of PDM should be adhered. In addition, there is a room for the use of other pharmacological agents.

Myocardial Perfusion Scans and Mortality in Asymptomatic Patients Awaiting Renal Transplantation.

Cardiac risk assessment for asymptomatic patients awaiting renal transplantation is controversial. Patients awaiting renal transplantation in Southern Saskatchewan from 2005 to 2015 were retrospectively reviewed. Patients underwent cardiac risk stratification with stress myocardial perfusion scan. Baseline clinical characteristics, nuclear scan results, all-cause mortality, and cardiovascular events were analyzed. Abnormal scans were defined as studies with reversible defects, wall motion abnormalities, lung uptake, or transient ischemic dilation. Descriptive statistics and survival analysis were calculated. Charts from 285 consecutive patients with 608 nuclear scans were analyzed. Mean age was 55.2 ± 11.7 years and 34.7% were female. Forty-three (15.1%) patients were transplanted and 99 (40.9%) patients died while awaiting renal transplantation. One hundred fifty-three patients (63.2%) had at least one abnormal scan. The mean follow-up period was 5.47 ± 3.11 years. An abnormal scan was not associated with decreased survival and/or coronary events (hazard ratio: 0.94, P = .77; 95% confidence intervals: 0.62 to 1.43). Patients awaiting renal transplantation in Saskatchewan with abnormal myocardial perfusion scans were not at greater risk of death or coronary events.

Prevalence of weight gain in patients with better renal transplant function.

AIMS: This study investigates the association between renal function and change in weight after kidney transplantation. METHODS: Retrospective analyses of 165 transplant patients on maintenance steroids who were followed-up for 6.2 +/- 2.4 years. RESULTS: 101 males and 64 females participated in the study. Results are expressed as mean +/- SD. At the first post-transplant outpatient visit (time 0), BMI was 25.3 +/- 4.8 kg/m2. It increased significantly by 7.7 +/- 10.8% and 10.9 +/- 12.6% at 1 and 5 years. 18 and 29% of patients had a BMI > 30 kg/m2 at times 0 and 5 years, respectively. Thereafter, diminishing glomerular filtration rate (GFR) was associated with the loss of the excess weight. Multivariate analysis showed that GFR, but not age, race, sex, source of graft, number of HLA mismatches or length of dialysis was significant to post-transplant weight gain. 38 patients gained weight > 1 SD above the mean of the population and were designated the high weight gain (HWG) group. 41 patients gained weight < the mean - 1 SD of the population and were designated the low weight gain (LWG) group. GFR in the high and low weight gain groups at time 0 was 71.8 +/- 20.3 ml/min/1.73 m2 and 66.4 +/- 23.1 ml/min/1.73 m2, respectively (p = NS), as compared to 77.4 +/- 23.3 ml/min/1.73 m2 and 61.5 +/- 24.5 ml/min/ 1.73 m2 at 6 months, respectively (p < 0.01) and continued to be significant thereafter (72.7 +/- 17.2 ml/min/1.73 m2 and 58.9 +/- 19.8 ml/min/1.73 m2, p < 0.05 at 6 years). CONCLUSIONS: Patients with relatively better renal transplant function gained more weight, suggesting a pivotal role of improved appetite on weight gain post transplantation. Most of the weight gain occurred during the first year.

Performance of creatinine clearance equations on the original Cockcroft-Gault population.

BACKGROUND: Prediction of endogenous creatinine clearance by mathematical equations such as the Cockcroft-Gault formula is used in clinical practice in spite of the reported concern for their limited predictability. The aim of this study is to determine whether the measured creatinine clearance can be predicted accurately by a number of published equations including the recently modified Cockcroft-Gault formula = Cockcroft-Gault formula x 1.73 m2/body surface area from the original Cockcroft-Gault population. METHODS: The performance of the mathematical equations in patients with different creatinine clearance and body mass indices was assessed by computing accuracy at different percentiles, bias and precision from the original Cockcroft-Gault data. RESULTS: Refitting the modified formula to the Cockcroft-Gault data gave superior results compared to the original Cockcroft-Gault formula with an overall accuracy in the general and subgroup analysis above 70% agreement within 30% estimate of the measured creatinine clearance. On the other hand, analysis of the other equations, including the original Cockcroft-Gault, demonstrated a limited accuracy to predict creatinine clearance particularly in patients with creatinine clearance below 50 ml/min with an overall accuracy in less than 1/3 of the calculated creatinine clearance within 30% range from the measured creatinine clearance. CONCLUSION: The current creatinine clearance equations and even the original Cockcroft-Gault formula did not accurately predict the measured creatinine clearance. Normalization for body surface area in the original Cockcroft-Gault formula demonstrated more accuracy to estimate creatinine clearance, particularly in patients with diminished renal function and is recommended to physicians who wish to use the Cockcroft-Gault formula in their practice until more credible formulas are developed.

Health Literacy, Knowledge, and Patient Satisfaction Before Kidney Transplantation.

BACKGROUND: Poor health literacy is associated with inferior outcomes in kidney transplant recipients, and knowledge remains suboptimal in this population. The goal of this study was to characterize the health literacy, kidney transplant knowledge, medication beliefs, and education satisfaction in a cohort of patients waiting to undergo kidney transplantation. METHODS: All patients on the wait-list in 1 Canadian center were invited to participate in the study. A research assistant administered the Short Test of Functional Health Literacy in Adults and its numeracy section, the Beliefs about Medicines Questionnaire, the Kidney Transplant Understanding Tool, and questions regarding satisfaction. Descriptive and univariate statistics were calculated between demographic variables and the assessments. RESULTS: Thirty-nine percent of patients (41 of 106) patients participated in the study. Overall, 95% and 86% were defined as having adequate health literacy and numeracy, respectively. The mean score on the Kidney Transplant Understanding Tool was 79%, and the majority (97.4%) had strong beliefs regarding the necessity of medication and little concern about adverse effects (73.8%). Participants with higher literacy scores had increased knowledge (r = 0.52; P = .05), understanding of why antirejection pills are necessary (r = 0.38; P = .05), and confidence about taking posttransplant medications (r = 0.32; P = .05). Overall, 30.7% were unsatisfied with their education regarding medications, and 22.5% were unsatisfied with what to expect after the transplant. CONCLUSIONS: Before transplantation, health literacy, transplant knowledge, and scores on the Beliefs about Medicines Questionnaire were high in this cohort of patients. However, patient satisfaction regarding educational content remained suboptimal.

The differential effect of alloantigen-blocking antibodies on unprimed and memory T helper cells.

Responsiveness to recall antigens by memory and naive T helper cells is different. To study whether such a difference is also applicable to affinity for allorecognition, we analyzed the effect of an IgG MLR blocking antibody separated from sera of patients with known kidney transplant chronic rejection on primed and unprimed CD4+ T cell alloreactivity. The results show that addition of the IgG fraction inhibits the patient's own unprimed T helper cell responses to a panel of four different alloantigens as well as a third-party mixed lymphocyte response. The same IgG fraction inhibited third-party naive T helper cell, but not autologous unprimed T helper cell, proliferation to adherent anti-CD3 antibody, which suggests that the mechanism of inhibitory action of the IgG is allogeneic-dependent. This IgG also did not induce inhibition of any of the T helper cell clone responsiveness, raised from the same or other patients, when stimulated with the same alloantigens used for unprimed cell alloactivation. Differential responses of naive and memory CD4+ T cells to alloantigens may explain some differences between the in vivo and in vitro systems and why allograft rejection can proceed in the presence of allogeneic blocking antibodies.

Heightened CD40 ligand gene expression in peripheral CD4+ T cells from patients with kidney allograft rejection.

BACKGROUND: CD40 ligand (CD40L) gene expression is increased in rejecting allograft biopsies. We, therefore, tested the possibility that CD40L gene expression is heightened in peripheral CD4+ T cells during renal allograft rejection. METHODS: CD40L gene expression in peripheral blood CD4+ T cells from two renal transplant groups was measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR). Group 1: 20 patients with excellent renal transplant function; group 2: 25 patients with findings of acute and/or chronic allograft nephropathy (CAN); and group 3 of 12 normal controls. CD4+ cells were isolated by positive selection. The modifying effect of cyclosporine (CsA) and FK506 on CD40L gene expression was further tested in vitro in CD4+ T lymphocytes separated from pokeweed mitogen- (PWM) activated peripheral blood lymphocytes (PBL) preparations. RESULTS: Mean+/-SD expressions of CD40L gene, in aM, in groups 1-3 were as follows: 0.0052+/-0.0094; 0.022+/-0.023 (P=0.0038 vs. group 2); and 0.014+/-0.005. Levels of CD40L gene expression correlated significantly with acute rejection Banff 97 score (R2=0.44, P=0.0004) and severity of intertubular capillary changes (ITCC) (R2=0.33, P=0.011). After in vitro activation, CD40L gene expression increased by approximately 4-fold and the addition of CsA or FK506 diminished CD40L gene expression to a base level. CONCLUSION: Peripheral CD4+ T cell CD40L gene expression increases significantly in acute rejection and CAN and may serve as a non-invasive method to monitor allograft function and determine the biological response to CsA and FK506.

Production of human alloreactive antibodies by uremic sensitized lymphocytes engrafted in severe combined immunodeficient mice.

BACKGROUND: Numerous studies have documented antibody responses to nominal antigens in human peripheral blood lymphocyte (hu-PBL)-severe combined immunodeficient (SCID) mice engrafted with PBL. We suggest, therefore, that engraftment of SCID mice by allosensitized cells produces alloreactive antibodies (allo-Ab). As such, SCID mice can be used as a model to examine the cellular basis of the sustenance of humoral alloresponses. METHODS: C.B-17 SCID mice were engrafted intraperitoneally with PBL from sensitized uremic patients for 5 weeks and classified into the following: group 1, 8 mice engrafted with unactivated cells (n = 5; n = sensitized patients); group 2, 6 mice engrafted with unactivated PBL (n = 3) followed 2 days later by in vivo activation with interleukin-2 (IL-2) and lipopolysaccharide (LPS); group 3, 11 mice engrafted with cells preactivated in vitro with IL-2 and LPS (n = 6); group 4, 9 mice engrafted with cells preactivated with irradiated allogeneic transformed B cells, IL-2, and LPS (n = 5); group 5, 10 mice engrafted with cells preactivated with IL-2, LPS, and HLA class II allopeptides and adjuvant (n = 6); group 6, 8 control mice engrafted with control cells preactivated with IL-2 and LPS. Two weeks later, each group was rechallenged by the same stimuli. Allo-Ab production was measured by the panel-reactive antibody PRA-STAT ELISA method. Results. Allo-Ab was produced in 54.5% of group 3, 43% of group 4; 80% of group 5, and 0% of groups 1, 2, and 6. The ratio of alloreactive positive wells in the allo-Ab-producing PBL-hu-SCID mice to that present in the respective patient's sera was 82%, 52%, and 87% in groups 3, 4, and 5, respectively. Conclusions. The study demonstrates the feasibility of using the hu-PBL-SCID model to study alloreactive memory B-cell function in humans. Discrete HLA-class allopeptides (group 5) appeared more potent allo-Ab producers than allogeneic cells (group 4).

HLA-identity--long-term renal graft survival, acute vascular, chronic vascular, and acute interstitial rejection.

The object is analysis of the impact of acute and chronic rejection on long-term function in HLA-identical renal transplants performed from 1967 to 1995 by the Saskatchewan Renal Transplant Unit. Forty-eight grafts in 46 patients were studied, of which 39 were first and nine second grafts. Forty-two were for primary and six for secondary renal disease. Thirty-five received azathioprine/prednisone prophylaxis, and 13 received cyclosporine/prednisone with/without azathioprine. Ten-year all graft actuarial survival was 84%, 10-year actuarial graft survival in patients with primary renal disease 90%, and with subsequent graft after first HLA graft failed 97.5%, for age-matched population 98.5% (P=NS). Overall death rate was 8.7% (4/46); in secondary renal disease patients 50% (3/6); in primary renal disease patients 2.5% (1/40, P=0.004). All (9/9) HLA-identical second grafts functioned. Acute rejection with azathioprine/prednisone prophylaxis occurred in 55% (9/17) of grafts treated with <6 pre-graft blood transfusions, with the same prophylaxis but >5 units in 12% (2/16, P=0.015), and with cyclosporine prophylaxis in 13% (2/15, P=0.021). Pulse steroids alone reversed all acute rejection. Grafts failed in 6.2% (3/48), all in primary renal disease patients and one from technical one noncompliance, and one chronic rejection. Graft cost/patient/year amortized over 9 years is $3,855 and comparable dialysis cost would be $35,650; cost for all patients on dialysis for 9 years would be $11,293,320 while comparable graft cost was 1,221,418, a savings of 89.2%. Our conclusions are that HLA-identity associates with the following: (1) a 10-year actuarial survival in primary renal disease that equals that of the age-matched population, (2) uniform success in repeat grafts, (3) virtual absence of chronic rejection despite a high incidence of acute rejection in azathioprine/prednisone grafts that (4) always reversed on pulse steroids, and (5) a cost reduction for grafting of 93.2% compared with dialysis therapy.

Analysis of the relationship between chimerism and the allgeneic humoral response.

BACKGROUND: Persistence of antigens has been suggested to play a role in two opposing immunological phenomena: tolerance and memory. Therefore, we studied the impact of chimerism on alloreactive antibody (allo-Ab) production in kidney transplant patients. METHODS: Thirty-five female renal transplant recipients of male donor organs were classified into the following groups: group 1, 13 sensitized uremic patients on dialysis; group 2, 5 nonsensitized uremic patients on dialysis; group 3, six sensitized patients experiencing graft rejection (3 acute vascular, 1 acute cellular, and 2 chronic); and group 4, 11 nonsensitized with functioning allografts (9 with good function, 1 with acute cellular rejection, and 1 with chronic rejection). Mean duration of dialysis after graft failure was similar in groups 1 (56+/-29.7 months) and 2 (41.8+/-42.4 months), as was dialysis efficiency. Chimerism was measured indirectly in the peripheral blood lymphocytes by polymerase chain reaction amplification of a specific Y chromosome DNA gene sequence with a detection sensitivity limit of 1 male cell per 1 million female cells. Allo-Ab production was measured by the PRA-STAT enzyme-linked immunosorbent assay (Sangstat) method. RESULTS: Chimerism was observed in 60% of groups 1 and 2, 83% of group 3, and 82% of group 4. Among all groups, graft existence, irrespective of its function, positively predicted chimerism in 92% with a sensitivity of 88% and a specificity of 78%. In group 3, all three patients with acute vascular rejection had chimerism and donor-specific allo-Abs. In group 4, eight of the nine patients with no rejection had chimerism. CONCLUSION: Chimerism relates to persistence of allogeneic stimulus irrespective of its function. Chimerism did not confer protection against allo-Ab production or vascular rejection, and its existence was not crucial for sustenance of allo-Ab production.

Alloantigen-blocking antibodies in sera from highly sensitized uremic patients: antibody class and relationship with lymphocytotoxins.

BACKGROUND: Previously, we identified an antimitogenic IgG antibody separated from sera of patients with known kidney transplant chronic rejection. This antibody inhibits individual patients' own unprimed T helper cell responses to alloantigens as well as a third-party mixed lymphocyte response, but does not inhibit autologous unprimed T helper cell proliferation to adherent anti-CD3 antibody. We suggest that the mechanism of inhibitory action is allogeneic-dependent. METHODS: We used a series of similar experimental designs to test the presence of this antibody in uremic, sensitized patients and have studied its relationship to sensitization as defined by the presence of lymphocytotoxins in four uremic groups: highly sensitized with or without previous graft loss, moderately sensitized with or without graft loss, nonsensitized without previous graft loss, and nonsensitized with graft loss. RESULTS: (1) Sensitization is associated with the presence of a potent antibody that blocks primary mixed lymphocyte response. Primed cells are less susceptible to its antimitogenic action. (2) The blocking antibody activity is present only in sensitized patients who have IgG lymphocytotoxic activity against the same HLA class I antigens. (3) The blocking activity is unequal in the following order: IgG 3 > IgG 1 > IgG 2. (4) Although IgG 1 and 2 fractions contain lymphocytotoxic activity against HLA class I antigens, the IgG 3 fraction does not. CONCLUSIONS: The differential effect of IgG antibodies on naive and memory T cells may explain why humeral responses to alloantigens can be maintained in the presence of blocking antibodies.

Safety and tolerability of cyclosporine and cyclosporine microemulsion during 18 months of follow-up in stable renal transplant recipients: a report of the Canadian Neoral Renal Study Group.

BACKGROUND: There has been concern that the increased drug exposure associated with treatment with cyclosporine microemulsion (CsA-ME) would lead to an increase in adverse events. METHODS: The long-term safety and tolerability of conventional cyclosporine (CsA) and CsA-ME were compared in a randomized, multicenter, pharmacoepidemiologic study involving 1097 stable renal transplant patients after 18 months of follow-up. RESULTS: No significant difference was seen in change in serum creatinine or calculated creatinine clearance between the two groups. Episodes of deterioration in renal function (change in serum creatinine > or = 20%) were categorized with the following results for CsA-ME versus CsA, respectively: acute rejection, 4.5% vs. 4.5%; chronic rejection, 8% vs. 11%; CsA nephrotoxicity, 12% vs. 7% (P=0.008); transient changes, 17% vs. 12%; other causes, 4% vs. 6%. During the first 6 months of the study, a transient increase in the incidence of gastrointestinal and neurological adverse events was seen in the CsA-ME group compared with the CsA group. Up to 18 months, patients in the CsA group reported significantly fewer hearing and vestibular disorders, but more cardiovascular problems than those in the CsA-ME group (P=0.035). CONCLUSIONS: Tolerance to CsA and CsA-ME was similar. Renal function over 18 months was not adversely affected by the increased drug exposure with CsA-ME, although there was a transient increase in nephrotoxicity. The frequency of acute and chronic rejection did not change.

A randomized, prospective multicenter pharmacoepidemiologic study of cyclosporine microemulsion in stable renal graft recipients. Report of the Canadian Neoral Renal Transplantation Study Group.

BACKGROUND: The safety, tolerability, and pharmacokinetics of conventional cyclosporine (ConCsA) and cyclosporine microemulsion (MeCsA) were compared under conditions of normal clinical practice in a prospective, randomized, concentration-controlled, pharmacoepidemiologic study. METHODS: Between September 1994 and March 1995, 1097 stable renal transplant recipients in 14 Canadian centers were randomized 2:1 to treatment with MeCsA or ConCsA. Patients were commenced on each study drug at a dose equal to their previous therapy with ConCsA, and the dose was adjusted to maintain predose whole blood cyclosporine concentrations within the therapeutic range established for each center. Prednisone and azathioprine were continued unless dose adjustment was required for clinical reasons. RESULTS: The mean cyclosporine concentration was comparable in both treatment groups at all time points throughout the 6 months of follow-up. The mean dose of cyclosporine was 3.6 mg/kg/day in both treatment groups at entry to the study, and declined by 0.3% and by 2.8% in patients receiving ConCsA and MeCsA, respectively. The nature and severity of adverse events were similar in both treatment groups, but there was a transient increase in neurological and gastrointestinal complications in the group receiving MeCsA within the first month after conversion (P<0.05). Serum creatinine and creatinine clearance did not change in either treatment group throughout the study. Biopsy-proven acute rejection occurred in three patients (0.8%) receiving ConCsA and in seven patients (0.9%) receiving MeCsA, with non-histologically proven acute rejection in an additional three patients (0.8%) receiving ConCsA and five patients (0.6%) receiving MeCsA (P=NS). Serum creatinine rose transiently in 35 patients (9.8%) receiving ConCsA and 138 patients (18.7%) receiving MeCsA (P<0.05) and resolved either spontaneously or after a reduction in the cyclosporine dose. One graft was lost in the MeCsA group due to irreversible rejection, and seven patients died, three in the group receiving ConCsA and four of those receiving MeCsA (P=NS). Absorption of cyclosporine was more rapid and complete from MeCsA than from ConCsA during the first 4 hr of the dosing interval, resulting in almost 40% greater exposure to the drug (P<0.001). There was close correlation between area under the time-concentration curve (AUC) over the first 4 hr of the 12-hr dosage interval and AUC over the entire 12-hr dosage interval for both formulations, making AUC over the first 4 hr a good predictor of total cyclosporine exposure. Using this parameter, patients with low absorption randomized to receive MeCsA showed a marked increase in drug exposure by months 3 and 6, whereas there was no change in those who continued on ConCsA. A limited sampling strategy utilizing samples at the predose and postdose trough levels provided an excellent correlation with drug exposure, particularly for patients receiving MeCsA (r2=0.94 MeCsA vs. r2=0.89 ConCsA). CONCLUSIONS: MeCsA appears to be a safe and effective therapy in stable renal transplant patients and provides superior and more consistent absorption of cyclosporine when compared with ConCsA. Transient toxicity after conversion to MeCsA occurs in some patients, and may reflect the increased exposure to cyclosporine. Use of a limited sampling approach combining trough and 2-hr postdose concentrations may provide an effective way to monitor this exposure.

Analysis of the CD40/CD40L role in the sustenance of alloreactive antibody production.

CD40 ligand (CD40L) is important for T/B lymphocyte interaction. To understand the cellular basis of humoral allosensitization we, therefore: (1) measured CD40L protein and gene expression in sensitized and non-sensitized uremic unactivated peripheral CD4+ T lymphocytes; (2) studied the impact of blocking the CD40/CD40L pathway on alloreactive antibody (allo-Ab) production by engrafted sensitized PBLs into severe combined immunodeficient (SCID) mice after in vitro preactivation with IL2/LPs/HLA class II allopeptides and adjuvants as a potent stimulus to produce allo-Ab (Shoker et al. Transplantation 1999;68;1188); and (3) studied the modifying effect of CD40/CD40L blockade on T helper type I and II cytokine gene expression in the respective mice spleen. The CD40L protein was measured by flow cytometry and the gene expression was measured by quantitative RT-PCR. Alloreactive antibodies (alo-Abs) produced by sensitized PBLs engrafted into SCID mice with and without blockade of the CD40 receptor were measured by the PRA-STAT ELISA method. The modifying effects of CD40 blocking on allo-Ab production and cytokine gene expression by the engrafted cells measured by RT-PCR were then compared. There was no detectable CD40L protein expression in either the uremic or the control groups. The CD40L gene expression of 0.04 +/- 0.02 attomoles (aM) in the sensitized group was significantly higher than in the non-sensitized patients (0.009 +/- 0.007 aM, P < 0.0001) or the control CD4+ T cells (0.016 +/- 0.004 aM, P < 0.001). Blockade of the CD40 receptor abrogated the production of allo-Ab antibodies by the engrafted sensitized cells in 60% of the tested mice (n = 10); decreased the mean +/- S.D. optic density of allo-Ab to 0.1 +/- 0.13 and the mean +/- S.D. PRA to 12 + 16). In the presence of the control Ab, allo-Ab production in SCID sera was present in 100% of the 10 SCID mice tested; the mean +/- S.D. PRA was 75 +/- 20, and the mean + S.D. OD activity was 0.412 +/- 0.17. All cytokine genes were, otherwise, expressed in the presence or absence of CD40 blockade. The results suggest a potential role of an enhanced CD40/CD40L interaction in the sustenance of alloreactive antibody production without significant deviation to T helper-like I or II responses. Blocking the CD40/CD40L pathway may have a potential therapeutic benefit to treat sensitized uremic patients.

Immunopharmacologic therapy in renal transplantation.

The long-term kidney allograft survival rate is still far from optimum. Conventional immunosuppressive drugs used to prevent allograft rejection are associated with significant side effects. Moreover, withdrawal of these agents is often associated with graft loss due to rejection. No treatment is available for chronic rejection. Graft tolerance is difficult to achieve in humans, and therefore a continued goal in organ transplantation is to develop immunosuppressive regimens that are associated with fewer side effects and decreased rates of rejection, and that promote graft tolerance. The advent of newer pharmacologic agents and bioreagents is expected to improve patient and graft survival rates.

Absence of irreversible rejection in the presence of warm anti-donor-HLA class I cytotoxic IgG antibody.

Since the initial presentation by Kissmeyer-Nielsen and colleagues [1966] and later by Patel and Terasaki [1969], it has been accepted that renal transplantation should not be performed in the presence of cytotoxic alloreactive antibodies of the IgG fraction performed at room temperature against HLA Class I [Braun 1989] antigens. Such antibodies are feared to induce hyper-acute or accelerated rejection because of the presence of HLA Class I antigens on kidney cells. For this reason, the microlymphocytotoxicity crossmatch (XM test: recipient serum reacted against donor lymphocytes as surrogate for HLA antigens) is now universally used before transplantation [Ting 1983]. A positive XM performed against the recipient T lymphocyte at room temperature after treatment of recipient serum with dithiothreitol (DTT), an agent that removes immunoglobulin M, denotes the presence of cytotoxic alloreactive IgG antibodies against the potential donor HLA class I antigen. Herein, we present the case of a patient who developed positive XM test of the IgG isotype against HLA Class I of the donor antigens performed at room temperature seven days after she received a kidney allograft from her daughter. Although the development of a positive XM was associated clinically with acute rejection, the patient responded remarkably well to anti-rejection therapy and maintained excellent graft function thereafter. Thus, strategies to identify the role played by the different IgG isotypes determined against HLA Class I antigens and their relation to irreversible rejection are needed to differentiate between those potential kidney recipients who may benefit from kidney transplantation in the presence of innocent warm IgG subclass antibodies reactive against HLA Class I antigens and those patients who may not.

Pseudohypoaldosteronism with normal blood pressure.

In adults, persistent hyperkalemic distal renal tubular acidosis in the absence of impaired renal function is an unusual abnormality usually associated with the syndromes of aldosterone deficiency or resistance. Herein, we present an adult with a clinical picture consisting of a normal blood pressure of 125/80 mmHg, normal blood volume, and glomerular filtration rate, with hyperkalemic distal renal tubular acidosis. The patent could spontaneously lower her urine pH to less than 5.5. Plasma renin activity was normal. Serum aldosterone level was appropriately elevated for the level of serum potassium. Following alkalinization of the urine, she was able to generate a urinary to blood PCO2 gradient [U-B PCO2] of 55 mmHg, and had a ten fold increased potassium secretion. After salt restriction and furosemide administration, her potassium secretion rate increased only twofold despite correction of he acidosis. The acidosis, as well as the hyperkalemia, was completely corrected after 9-alpha-Fluorohydrocortisone administration. Hydrochlorothiazide corrected the acidosis and hyperkalemia. Collectively, this picture suggests an underlying chloride shunt as the possible pathophysiological mechanism. Our case in unique in that it is not associated with hypertension.

In vitro IgG1 alloreactive antibody production by circulating memory cells in humans.

This study was designed to investigate the presence of IgG1 alloreactive memory cells in the peripheral blood in humans and their in vitro activation requirements. Alloreactive antibody production was measured after cell activation with cytokines: Interleukin (IL) 2, IL-4 and IL-10, interferon gamma, alloantigens and/or OKT3, lipopolysaccharide or Pokeweed mitogen and Epstein-Barr virus transformation. The examined cells were taken from ten sensitized and five nonsensitized uremic patients with previous graft loss and five normal controls. The titers and percentage panel reactive IgG1 antibody reactivity present in the respective sera was further compared with the in vitro profile. Alloreactive antibody reactivity was measured by PRA-STAT ELISA method. The results show that: 1) Short term control T cell lines or nonsensitized cells were unable to provide the necessary help to autologous B cells to produce alloreactive antibodies of the IgG subclass. 2) Activated cells from sensitized patients produced low levels of alloreactive IgGl antibodies. 3) Stimulation with any of the cytokines and/or mitogens or alloantigens or allopeptides was not sufficient to produce consistent levels of alloreactive IgG 1 antibodies, in spite of its presence in the respective sera.