Role of time from transplantation to biopsy in histologic ABMR: A single center report.

BACKGROUND: Allograft biopsies with lesions of Antibody-Mediated Rejection (ABMR) with Microvascular Inflammation (MVI) have shown heterogeneous etiologies and outcomes. METHODS: To examine factors associated with outcomes in biopsies that meet histologic ABMR criteria, we retrospectively evaluated for-cause biopsies at our center between 2011 and 2017. We included biopsies that met the diagnosis of ABMR by histology, along with simultaneous evaluation for anti-Human Leukocyte Antigen (HLA) donor-specific antibodies (DSA). We evaluated death-censored graft loss (DCGL) and used a principal component analysis (PCA) approach to identify key predictors of outcomes. RESULTS: Out of the histologic ABMR cohort (n = 118), 70 were DSA-positive ABMR, while 48 had no DSA. DSA(+)ABMR were younger and more often female recipients. DSA(+)ABMR occurred significantly later post-transplant than DSA(-)ABMR suggesting time-dependence. DSA(+)ABMR had higher inflammatory scores (i,t), chronicity scores (ci, ct) and tended to have higher MVI scores. Immunodominance of DQ-DSA in DSA(+)ABMR was associated with higher i+t scores. Clinical/histologic factors significantly associated with DCGL after biopsy were inputted into the PCA. Principal component-1 (PC-1), which contributed 34.8% of the variance, significantly correlated with time from transplantation to biopsy, ci/ct scores and DCGL. In the PCA analyses, i, t scores, DQ-DSA, and creatinine at biopsy retained significant correlations with GL-associated PCs. CONCLUSIONS: Time from transplantation to biopsy plays a major role in the prognosis of biopsies with histologic ABMR and MVI, likely due to ongoing chronic allograft injury over time.

Influence of patient characteristics and immunosuppressant management on mortality in kidney transplant recipients hospitalized with coronavirus disease 2019 (COVID-19).

The influence of patient characteristics and immunosuppression management on COVID-19 outcomes in kidney transplant recipients (KTRs) remains uncertain. We performed a single-center, retrospective review of all adult KTRs admitted to the hospital with confirmed COVID-19 between 03/15/2020 and 05/15/2020. Patients were followed from the date of admission up to 1 month following hospital discharge or study conclusion (06/15/2020). Baseline characteristics, laboratory parameters, and immunosuppression were compared between survivors and patients who died to identify predictors of mortality. 38 KTRs with a mean baseline eGFR of 52.5 ml/min/1.73 m2 were hospitalized during the review period. Maintenance immunosuppression included tacrolimus (84.2%), mycophenolate (89.5%), and corticosteroids (81.6%) in the majority of patients. Eleven patients (28.9%) died during the hospitalization. Older age (OR = 2.05; 1.04-4.04), peak D-dimer (OR = 1.20; 1.04-1.39), and peak white blood cell count (OR = 1.11; 1.02-1.21) were all associated with mortality among KTRs hospitalized for COVID-19. Increased mortality was also observed among KTRs with concomitant HIV infection (87.5% vs. 36.1%; p < .01). Conversely, immunosuppression intensity and degree of reduction following COVID-19 diagnosis were not associated with either survival or acute allograft rejection. Our findings potentially support a strategy of individualization of immunosuppression targets based on patient-specific risk factors, rather than universal immunosuppression reduction for KTRs at risk from COVID-19.

Conversion to belatacept maintenance immunosuppression in HIV-positive kidney transplant recipients.

There are only scattered case reports documenting belatacept use in HIV + kidney transplant recipients. We performed a retrospective review to describe short-term outcomes following conversion to belatacept in a cohort of HIV + patients. Patients were included if they were converted to belatacept between May 2015 and May 2019, had an HIV- donor, and received ≥4 doses of belatacept. All patients were treated with non-depleting induction and triple maintenance immunosuppression. Allograft and HIV-related outcomes were collected from the date of belatacept infusion until May 2020. Ten HIV + kidney transplant recipients were identified, who were converted to belatacept a median of 364 days post-transplant. At last follow-up (median 3.3 years), 8 patients remained on belatacept therapy, and all patients were alive with functioning allografts. Mean estimated glomerular filtration rates (eGFR) improved from 31.6 mL/min at baseline to 42.8 mL/min at 1 year (P = .03). Two patients developed acute rejection, with one necessitating conversion back to tacrolimus. All patients maintained undetectable HIV-1 viral loads at last follow-up. One patient each developed pneumocystis pneumonia and Kaposi sarcoma following conversion, which were responsive to standard medical therapy. In our cohort of stable HIV + kidney transplant recipients, conversion to belatacept was associated with excellent early patient and allograft survival and improved eGFR at 1 year.

Conversion to belatacept within 1-year of renal transplantation in a diverse cohort including patients with donor-specific antibodies.

Early conversion from a calcineurin inhibitor to belatacept has the potential to improve long-term renal allograft function; however, there remains limited experience with this strategy among African Americans and patients with preformed donor-specific antibodies (DSA). To examine these subgroups, we performed a single-center review of kidney transplant recipients converted to belatacept within 1-year of transplant between 01/2011 and 10/2017. All patients received lymphocyte-depleting induction with maintenance tacrolimus and mycophenolate +/- corticosteroids. Patients were switched to belatacept for clinical indication and followed from date of conversion until allograft failure or study conclusion. The primary endpoint at 1-year was a composite of allograft loss, biopsy proven rejection, de novo DSA formation, proteinuria, and declining renal function. Thirty-two patients were included in the review. The majority were African American, and 28.1% had DSA at transplant. Patient and allograft survival at 1-year was 96.9% and 93.8%, respectively, and estimated glomerular filtration rate improved from 41.9 to 58.4 mL/min. No African Americans or patients with pretreatment DSA developed rejection or allograft failure within 1-year. The only clinical variable correlated with suboptimal allograft function was baseline weight ≥80 kg (OR = 6.2; 95% CI, 1.2-32.3). Early conversion to belatacept appears safe for select patients with DSA and African Americans receiving lymphocyte-depleting induction.

Liver, simultaneous liver-kidney, and kidney transplantation from hepatitis C-positive donors in hepatitis C-negative recipients: A single-center study.

Transplantation of organs from hepatitis C virus (HCV)-antibody (Ab) and -nucleic acid test (NAT) positive donors into HCV-negative recipients has been proposed to expand the donor pool and shorten waiting times. Data on early single-center outcomes are lacking. Nineteen liver (LT, including seven simultaneous liver-kidney [SLKT]) and 17 kidney transplant (KT) recipients received organs from HCV (+) donors; of these, 13 were HCV NAT (+) in each group. All patients who received organs from HCV NAT (+) donors developed HCV viremia post-transplant except for 2 KT recipients. Patients were treated with a variety of direct-acting antiviral regimens, with high rates of sustained virologic response among those with at least 12 weeks of follow-up past the end of treatment: 12/13 (92%) and 8/8 (100%) among LT/SLKT, and KT recipients. Median time to treatment start was 42 days (interquartile range [IQR] 35-118 days) and 40 days (IQR 26-73) post-LT/SLKT and KT, respectively. One death occurred in a SLKT recipient unrelated to HCV or its treatment. There was no significant increase in rejection, proteinuria, or changes in immunosuppression in any group. Organs from HCV-viremic donors can be utilized for HCV-uninfected recipients with good short-term outcomes.

Kidney transplantation using lymphocyte depleting induction and standard maintenance immunosuppression at the height of the SARS-CoV-2 pandemic in New York City: A single-center experience.

BACKGROUND: Concerns have been raised regarding proceeding with kidney transplantation using standard immunosuppression in COVID-19 endemic areas. METHODS: We performed a single-center review of all adult kidney transplants performed during the COVID-19 pandemic in New York City. Patients were managed with standard immunosuppression protocols, including lymphocyte depleting induction and trough-guided tacrolimus. Retrospective data were collected for 3 months from the date of transplantation or until study conclusion (5/7/2020). The primary outcomes assessed included patient and allograft survival as well as COVID-19 related hospital readmission. RESULTS: 30 kidney transplants were performed during the height of the COVID-19 pandemic. After a median follow-up of 51.5 days, 93.3% of patients were alive with 100% death-censored allograft survival. 9 patients were readmitted to the hospital during the study period, 4 (13.3%) related to infection with COVID-19. Infections were mild in 3/4 patients, with one patient developing severe disease leading to respiratory failure. Patients readmitted with COVID-19 were numerically more likely to be African American, have a BMI > 30 kg/m2, have a lymphocyte count ≤ 300 cells/mL, and be on maintenance corticosteroids. CONCLUSIONS: Kidney transplantation in areas endemic to COVID-19 using standard induction and maintenance immunosuppression appears to be associated with a modest risk for severe COVID-19 related disease.

Different outcomes after kidney transplantation between African Americans and Whites: A matter of income? A single-center study.

BACKGROUND: Our center has one of the largest representations of African Americans in listed and transplanted patients. We investigated if and how racial differences affect outcomes in our patient population. METHODS: We performed a retrospective analysis of all kidney transplants in African American and (non-Hispanic) White patients in our center from 1/1/2005 to 12/31/2014. Cox regression was performed to evaluate the adjusted hazard ratios for graft loss. We investigated the influence of socioeconomic status on transplant outcomes. We stratified our patients into three groups based on income: lower (<$50 000 annual household income), medium ($50 000-100 000 annual household income), and higher (>$100 000 annual household income. RESULTS: There were 1333 patients in our study, 696 Whites and 637 African Americans. The 1-, 5-, and 10-year graft survival between the two groups was 96.5% vs 91.1%, 89% vs 80.7%, and 77% vs 66.3%, respectively (P < .001 by Log Rank, Breslow and Taron-Ware). When we compared the two groups separately in each income category, we found no statistical difference between African Americans and Whites in graft survival. In the regression model, income and not race was the significant factor influencing graft survival (P < .001 vs P = .61).

Acanthamoeba endophthalmitis during treatment for cutaneous disease in a renal transplant patient.

Acanthamoeba infections are difficult to diagnose and treat. We present a renal transplant patient who developed Acanthamoeba endophthalmitis on therapy with posaconazole and miltefosine for cutaneous acanthamobiasis. The patient was maintained on intracameral voriconazole injections, and oral azithromycin, fluconazole, and flucytosine. This case highlights novel presentations and treatments for acanthamoebic infection.

Differences in Attitudes Toward Immunosuppressant Therapy in a Multi-ethnic Sample of Kidney Transplant Recipients.

Barriers for renal transplant patients to immunosuppressant medication adherence are poorly understood, despite the high rate and toll of non-adherence. We sought to assess factors that contribute to barriers to immunosuppressive medication adherence in an ethnically diverse sample of 312 renal transplant patients recruited from three transplant centers across New York City. Transplant patients who were at least 6 months post-transplant completed questionnaires while waiting for their medical appointment. Ethnic differences were observed on barriers to immunosuppressant adherence. Black and Hispanic participants reported significantly more barriers to adherence compared to Caucasian participants. Differences in perception about the potential harm and necessity of immunosuppressant medications also were present. Using hierarchical multiple regression, age and income were significant predictors of reported barriers to adherence, even while controlling for ethnicity. The most robust predictor of reported barriers was the perception of the medication cost-benefit differential, i.e., the balance between concerns about immunosuppressant medications and their perceived helpfulness (B = - 0.5, p < .001), indicating that varying beliefs about the medication's necessity and utility rather than ethnicity explain the differences in barriers to medication adherence. Future interventions targeting non-adherence should aim to reduce the barriers to adherence by addressing perceived risks and benefits of taking immunosuppressant medication.

Clinical and molecular significance of microvascular inflammation in transplant kidney biopsies.

The diagnostic criteria for antibody-mediated rejection (AMR) are continuously evolving. Here we investigated the clinical and molecular significance of different Banff microvascular inflammation (MVI) scores in transplant kidney biopsies. A total of 356 patients with clinically indicated kidney transplant biopsies were classified into three groups based on MVI scores of 0, 1, 2, or more for Groups 1-3, respectively. Gene expression profiles were assessed using arrays on a representative subset of 93 patients. The incidence of donor-specific anti-HLA antibodies was increased from 25% in Group 1 to 36% in Group 2 and to 54% in Group 3. Acute and chronic AMR were significantly more frequent in Group 3 (15% and 35%) compared with the Group 2 (3% and 15%) and Group 1 (0% and 5%), respectively. Gene expression profiles showed increased interferon-γ and rejection-induced, cytotoxic and regulatory T-cell, natural killer cell-associated and donor-specific antibody (DSA)-selective transcripts in Group 3 compared with Groups 1 and 2. There was no significant difference in gene expression profiles between the Groups 1 and 2. Increased intragraft expression of DSA-selective transcripts was found in the biopsies of C4d- Group 3 patients. Thus, an MVI score of 2 or more was significantly associated with a histological diagnosis of acute and chronic antibody-mediated rejection. Hence, increased intragraft DSA-selective gene transcripts may be used as molecular markers for AMR, especially in C4d- biopsies.

Pregnancy in sensitized kidney transplant recipients: a single-center experience.

BACKGROUND: We aimed to examine the clinical outcomes of sensitized pregnant kidney transplant recipients. METHODS: A retrospective cohort study of female patients who received kidney transplant at Montefiore transplant center between June 1, 2009 through December 31, 2014 and had a documented pregnancy in our system. RESULTS: We found that 11 women had pregnancies during this period with a median age of 36 yr (range 22, 39). Pregnancies occurred at a median of 3.1 yr (1.1, 8.7) after transplantation. Pre-pregnancy patients' median serum creatinine levels and spot urine protein/creatinine ratio were 1.1 mg/dL (1.1, 2.1) and 0.55 g/d (0, 1.2), respectively. Eight patients were sensitized with panel reactive antibody (PRA) levels > 0% and three had PRA of 0%. The sensitized group had a higher incidence of adverse pregnancy outcomes; one stillbirth and two second trimester miscarriage. During a median follow-up of 2.3 yr (1.2, 4) after delivery, three high PRA patients (37%) developed antibody-mediated rejection that led to graft loss. CONCLUSIONS: We observed an increased risk of rejection, graft loss, and adverse pregnancy outcomes in sensitized kidney recipients.

Kidney transplant complications from undiagnosed benign prostatic hypertrophy.

BACKGROUND: It is estimated that approximately 50% of males over 50 have benign prostatic hypertrophy (BPH). BPH is underappreciated in anuric patients with end stage renal disease, and failure of diagnosis in this population can lead to complications after kidney transplantation. METHODS: A single-center retrospective review of male patients over 50 yr of age transplanted from January 1, 2010, until September 30, 2013, was performed. Outcomes assessed were as follows: graft survival, urinary retention, discharge with Foley catheter, and urinary tract infection (UTI). RESULTS: Of 147 patients, 17.0% were diagnosed with BPH before transplant, 19.0% received a BPH diagnosis after transplant, and 64% did not have BPH. Compared to those without BPH, a post-transplant BPH diagnosis was associated with urinary retention during the transplant admission (0% vs. 46.4%, p < 0.01), discharge with Foley catheter (0% vs. 21.4%, p < 0.01), readmission related to urinary retention (0% vs. 46.4%, p < 0.01), and UTI (18.0% vs. 64.3%, p < 0.01). Patients with prior diagnosis of BPH and on therapy had similar outcomes to those without BPH. CONCLUSIONS: Following kidney transplant, urinary tract complications are more common in patients with BPH; however, being on medical therapy prior to transplantation diminishes the incidence of these complications significantly.

Kidney transplantation in patients with severe preoperative hypertension.

BACKGROUND: Severe systemic hypertension (HTN) is a risk factor for perioperative cardiovascular complications; however, its impact at the time of kidney transplantation (KTX) is not well defined. METHODS: A retrospective cohort study of adult kidney-only transplant recipients between October 2009 and December 2012 was performed to examine outcomes between patients with (n = 111) and without (n = 98) severe preoperative HTN defined as SBP > 180 or DBP > 110 mmHg. RESULTS: Recipients with severe HTN were older (56.7 ± 13.0 vs. 53.5 ± 12.4 yr, p = 0.07) and significantly more likely to receive an expanded criteria donor kidney (32.7% vs. 12.2%, p = 0.02). No patients developed hypertensive crisis, intracranial hemorrhage, or life threatening ventricular arrhythmias within 30 d post-transplantation; however, three patients with severe HTN had cardiac events: two with demand ischemia and one with decompensate heart failure. Two patients in the control group had decompensated heart failure. There were no differences between the groups in terms of cardiac event (2.7% vs. 2.0%, p = 0.75), one-yr patient survival (98.2% vs. 98.0%, p = 0.90) or graft survival (90.1% vs. 92.9%, p = 0.48), nadir creatinine > 2 mg/dL (4.6% vs. 6.2%, p = 0.62), length of stay > 6 d (37.8% vs. 35.7%, p = 0.75), and DGF (52.3% vs. 63.3%, p = 0.11). CONCLUSIONS: Our results suggest that severe preoperative HTN should not be considered an absolute contraindication to kidney transplant in patients who are otherwise clinically stable.

Increased intragraft rejection-associated gene transcripts in patients with donor-specific antibodies and normal biopsies.

We investigated why some donor-specific antibody-positive patients do not develop antibody-mediated rejection. Of 71 donor-specific antibody-positive patients, 46 had diagnosis of antibody-mediated rejection and 25 had normal biopsies. Fifty donor-specific antibody-negative patients with normal biopsies were used as a control group. A subgroup of 61 patients with available biopsy and 64 with blood samples were analyzed by microarrays. Both donor-specific antibody-positive/antibody-mediated rejection-positive and negative biopsies showed increased expression of gene transcripts associated with cytotoxic T cells, natural killer cells, macrophages, interferon-gamma, and rejection compared to donor-specific antibody-negative biopsies. Regulatory T-cell transcripts were upregulated in donor-specific antibody-positive/antibody-mediated rejection-positive and B-cell transcripts in donor-specific antibody-positive/antibody-mediated rejection-negative biopsies. Whole-blood gene expression analysis showed increased immune activity in only donor-specific antibody-positive/antibody-mediated rejection-positive but not negative patients. During a median follow-up of 36 months, 4 donor-specific antibody-positive/antibody-mediated rejection-negative patients developed antibody-mediated rejection, 12 continued to have donor-specific antibody, but 9 lost their donor-specific antibody. Gene expression profiles did not predict the development of antibody-mediated rejection or the persistence of donor-specific antibody. Thus, donor-specific antibody-positive/antibody-mediated rejection-negative patients had increased rejection-associated gene transcripts in their allografts despite no histologic findings of rejection but not in their blood. This was found in both biopsy and blood samples of donor-specific antibody-positive/antibody-mediated rejection-positive patients.

Campath induction in HCV and HCV/HIV-seropositive kidney transplant recipients.

Alemtuzumab (AZ) induction in hepatitis C-seropositive (HCV+) kidney transplant (KTX) recipients may negatively affect patient survival; however, available information is scant. Using US registry data from 2003 to 2010 of adult HCV+ deceased-donor KTXs (n = 4910), we examined outcomes by induction agent - AZ (n = 294), other T cell-depleting agents, (n = 2033; T cell), IL-2 receptor blockade (n = 1135; IL-2RAb), and no induction (n = 1448). On multivariate analysis, induction therapy was associated with significantly better overall patient survival with AZ [adjusted hazards ratio (aHR) 0.64, 95% confidence interval (CI) 0.45, 0.92], T cell (aHR 0.52, 95% CI 0.41, 0.65) or IL-2RAb (aHR 0.67, 95% CI 0.53, 0.87), compared to no induction. A significant protective effect was also seen with AZ (aHR 0.63, 95% CI 0.40, 0.99), T cell (aHR 0.62, 95% CI 0.49, 0.78), and IL2R-Ab (aHR 0.62, 95% CI 0.47, 0.82) in terms of death-censored graft survival relative to no induction. There were 88 HIV+/HCV+ coinfected recipients. Compared to noninduction, any induction (i.e. three induction groups combined) was associated with similar overall patient survival (P = 0.2255) on univariate analysis. Induction therapy with AZ, other T cell-depleting agents, or IL-2RAb in HCV+ KTX is associated with better patient and death-censored graft survival compared to noninduction. In HCV/HIV coinfected patients, induction is not contraindicated.

Differential outcomes in 3 types of acute antibody-mediated rejection.

INTRODUCTION: The aim of this study is to investigate the prevalence, predictors, and clinical outcomes of acute antibody-mediated rejection (AAMR). METHODS: Retrospective analysis of 833 adult patients who received kidney transplantation between 1/1/2001 and 8/15/2007. RESULTS: The prevalence of AAMR and acute cellular rejection was 2% and 8.2%, respectively. Eight patients had type I, seven type II, and two type III AAMR. All patients had at least one strong donor-specific anti-HLA antibodies (DSA) with a median fluorescence intensity (MFI) value of over 6000 and the mean number of strong DSAs was 2.0 +/- 0.7. Fifteen of 17 patients received pre-transplant desensitization treatment. During a median 28 months of follow-up (range: 12-38 months), two patients died (88% patient survival), and nine lost their allografts (35% graft survival). While all type I AAMR patients responded to treatment, all type III patients, and four of seven patients with type II AAMR lost their allografts earlier, and three type II AAMR patients later due to transplant glomerulopathy. CONCLUSIONS: AAMR is mainly seen in patients with pre-transplant strong DSAs. There is a striking difference in clinical outcomes of AAMR that types II and III AAMR patients have poor prognosis compared to type I AAMR patients.

Increased access to transplantation of highly sensitized patients under the new kidney allocation system. A single center experience.

We aimed to investigate the impact of the new kidney allocation system (KAS) on the rate of transplantation of sensitized patients at our center. Pre-KAS and post-KAS intervals were Jan 1st to Dec 3rd 2014 and Jan 1st 2015 to Dec 3rd 2015, respectively. The number of deceased-donor crossmatches performed by flow cytometry increased from 715 pre-KAS to 1188 post-KAS. The percent of crossmatches performed for sensitized patients with calculated panel reactive antibody (cPRA)>0% increased from 19% pre-KAS to 26% post-KAS (p<0.0001). The number of deceased-donor kidney transplants performed at our center increased from 115 pre-KAS to 125 post-KAS (9% increase). There was a significant increase in the percentage of deceased-donor kidney transplants received by sensitized candidates (from 14% to 26% pre- and post-KAS, respectively; p<0.0001). The highest increase was seen in the patients with cPRA>98%, from 0% to 9%, followed by the group with cPRA 50-79%, from 5% to 8%. This increase was balanced by a decrease of 12% in the percentage of non-sensitized recipients, and a modest decrease of 1% in the group with cPRA 1-49%. In conclusion, transplant rate has increased in sensitized patients after KAS. The highest increase was observed among highly sensitized patients (cPRA>98%).

Clinical, Histological, and Molecular Markers Associated With Allograft Loss in Transplant Glomerulopathy Patients.

BACKGROUND: We aimed to investigate the clinical, histopathological, and molecular factors associated with allograft loss in transplant glomerulopathy (TGP) patients. METHODS: Of the 525 patients who underwent clinically indicated kidney biopsies, 52 (10%) had diagnosis of TGP. Gene expression profiles of 28 TGP and 11 normal transplant kidney biopsy samples were analyzed by Affymetrix HuGene 1.0 ST expression arrays. RESULTS: Over a median follow up of 23 months (1-46 months) after the diagnosis of TGP by biopsy, 17 patients (32%) lost their allografts at a median of 16 months (1-44 months). There was no difference between the 2 groups in terms of any demographic variables, serum creatinine, panel reactive antibody levels, donor-specific antibody frequency, or mean fluorescence intensity values. Patients who lost their allograft had a significantly higher median spot protein to creatinine ratio 2.81 (1.20-6.00) compared to no graft loss patients 1.16 (0.15-2.53), (P < 0.01), and a trends toward a higher mean chronic glomerulopathy (cg) score (1.65 ± 0.93 vs 1.11 ± 0.93) (P = 0.05). There was also no difference in microvascular inflammation or any other Banff injury scores between the 2 groups. Although 117 gene transcripts were upregulated in both groups, 86 and 57 were upregulated in graft loss and functioning allograft groups, respectively. There were significantly increased levels of intragraft endothelial cell-associated transcripts, gene transcripts associated with complement cascade, interleukins and their receptors and granulysin in graft loss patients compared to patients with a functioning allograft. CONCLUSION: Our results demonstrate differential intragraft gene expression profiles in TGP patients with allograft loss.

Genomics of BK viremia in kidney transplant recipients.

BACKGROUND: This study aimed to investigate global gene expression profiles of BK viremia and nephropathy (BKVN) samples using microarrays to investigate the immunologic response to BK virus. METHODS: Patients were monitored for BK viremia in the blood monthly for 6 months, then at 9 and 12 months after kidney transplantation. BKVN and normal transplant kidney biopsy samples, and whole blood samples of patients with and without BK viremia were analyzed by Affymetrix Human Gene 1.0 ST Arrays. RESULTS: During a mean follow-up of 917±325 days, 61 of the 289 patients (21%) developed BK viremia at a median 149 (27, 1,113) days after transplantation with a median peak PCR titers of 35,900 (1,000, 2,677,000). The only significant risk factor for development of BK viremia was induction with anti-thymocyte globulin (P=0.03). Only four patients developed BKVN (1.3%). Pathogenesis-based transcript analysis revealed a significant increased expression of interferon-gamma and rejection induced (GRIT), quantitative cytotoxic T-cell (QCAT), quantitative constitutive and alternate macrophage, B-cell and natural killer cell-associated transcripts (NKAT), indicating an active inflammatory immune response in BKVN biopsies (n=3) compared to normal transplant kidney biopsies with (n=3) and without BK viremia (n=11). The whole blood gene expression profiles of 19 BK viremia patients revealed significant increased expression of GRIT, QCAT, and NKAT compared to 14 patients without viremia. CONCLUSIONS: The results showed increased activity of cytotoxic T cells and natural killer cells in BKVN and viremia samples resembling acute rejection and suggested the involvement of both adaptive and innate immunity.

Pretransplant immunologic risk assessment of kidney transplant recipients with donor-specific anti-human leukocyte antigen antibodies.

BACKGROUND: Patients with pretransplantation strong donor-specific anti-human leukocyte antigen (HLA) antibodies (DSA) are at higher risk for rejection. We aimed to study the safety of kidney transplantation in patients with lower strength DSAs in a prospective cohort study. METHODS: Three hundred and seventy-three consecutive adult kidney transplant recipients with (DSA+; n=66) and without (DSA-; n=307) DSA were evaluated. Anti-HLA antibodies with mean fluorescence intensity values over 5,000 for HLA-A, HLA-B, and HLA-DR and more than 10,000 for HLA-DQ were reported as unacceptable antigens. Patients received transplant if flow cytometry T-cell and B-cell cross-match channel shift values were less than 150 and 250, respectively, with antithymocyte globulin and intravenous immunoglobulin induction treatment. RESULTS: Patients had a mean number of 1.6 ± 0.8 DSAs with a mean fluorescence intensity value of 2,815 ± 2,550. Twenty-seven percent were flow cytometry cross-match positive with T-cell and B-cell channel shift values of 129 ± 49 and 159 ± 52, respectively. During a median follow-up of 24 months (range, 6-50), there were no statistically significant differences in patient (99% vs. 95%) and graft survival (88% vs. 90%) rates between DSA+ and DSA- groups, respectively. Cumulative acute rejection rates of 11% in the DSA+ group and 12% in the DSA- group were similar. Two DSA+ (3%) and five DSA- (2%) patients developed chronic antibody-mediated rejection (3%). The mean serum creatinine levels were identical between the two groups (1.4 ± 0.6 mg/dL). CONCLUSION: Similar patient and graft survival, and acute rejection rates can be achieved in DSA+ patients compared to DSA- patients with pretransplantation immunologic risk assessment.