Impact of belatacept conversion on kidney transplant function, histology, and gene expression - a single-center study.

Prior studies on belatacept conversion from calcineurin inhibitor (CNI) have been limited by an absence of postconversion surveillance biopsies that could underestimate subclinical rejection, or a case-controlled design. A total of 53 adult patients with allograft dysfunction underwent belatacept conversion (median: 6 months) post-transplant. At a median follow-up = 2.5 years, patient survival was 94% with a death-censored graft survival of 85%. Seven (13%) patients had acute rejection (including 3 subclinical) at median 6 months postconversion. Overall, eGFR improved (P = <0.001) from baseline = 31±15 to 40.2 ± 17.6 ml/min/1.73m2 by 6 months postconversion, but then stayed stable. This improvement was also observed (P < 0.001) in comparison with a propensity matched control cohort on CNI, where eGFR stayed stable (mean ~ 32ml/min/1.72m2 ) over 2-year follow-up. Patients converted < 6 months post-transplant were more likely to have a long-term improvement in kidney function. Paired gene expression analysis of 30 (of 53) consecutive pre- and postconversion surveillance biopsies did not reveal changes in inflammation/acute injury; although atrophy-fibrosis score worsened (mean = 0.28 to 0.44; P = 0.005). Thus, improvement in renal function with belatacept conversion occurred early and then sustained in comparison with controls where renal function remained unchanged overtime. We were unable to show molecular signals that could be related to CNI administration and regressed after withdrawal.

Tumor necrosis factor beta gene polymorphisms associated with urinary tract infections after renal transplantation.

INTRODUCTION: We investigated whether tumor necrosis factor (TNF) beta(low) or TNFbeta(high) alleles predicted susceptibility to infection or rejection after renal transplantation. METHODS: TNFbeta alleles were determined in 137 (ESRD) patients and correlated with urinary tract infections and rejection within 60 days among 75 consecutive renal transplant recipients. RESULTS: TNFbeta low was more prevalent among African-Americans than caucasians (83 vs. 63%, P=0.02). After renal transplantation, patients with TNFbeta low experienced more urinary tract infections (50 vs. 10%, P=0.002). The incidence of TNFbeta low and urinary tract infections were equivalent in patients treated with mycophenolate mofetil/cyclosporine (CsAA) (n=37) versus mycophenolate mofetil/tacrolimus (n=38). TNFbeta low was not associated with the incidence of delayed graft function (5 vs. 2, P=NS), early rejection (21 vs. 18%, P=NS) or actuarial 1-year graft survival (96 vs. 90%, P=NS). CONCLUSIONS: TNFbeta low was associated with urinary tract infections and TNFbeta high was associated with freedom from urinary tract infections. Neither gene correlated with rejection or l-year graft survival.

CXCR3 Expression Elevated on Peripheral CD8(+) Lymphocytes from HIV/HCV Coinfected Individuals.

HIV/HCV coinfected patients tend to develop hepatitis C (HCV)-associated liver disorders. Because the chemokine receptor CXCR3 participates in lymphocyte trafficking during hepatic inflammation, it may participate in the escalated liver disorders of coinfected patients. However, to date, the relative frequency and density of receptor on lymphocytes has not been established. This study compared the CXCR3(+) phenotype under various in vitro conditions between lymphocytes from healthy and coinfected individuals. Peripheral lymphocytes were stimulated with phytohemagluttinin for 0-7 d and phenotypes were determined by flow cytometry. Secreted cytokines were measured in culture supernatants by ELISA. Phenotypic differences were observed between groups. CD4(+)CXCR3(+) frequency between groups was equivalent before and during early activation, but increased only among non-infected individuals during late activation (p<0.001). In contrast, CD8(+)CXCR3(+) frequency was consistently greater (p<0.05) among HIV/HCV patients throughout activation. Among those who were non-infected, CD8(+)CXCR3(+) frequency increased (p=0.002) during late activation. However, CD8(+)CXCR3(+) frequency among HIV/HCV patients increased within 24 h of activation (p=0.008), and was nearly universal by late activation (p<0.001). Both groups elaborated Th-1 cytokine profiles; however, coinfected patients released more inflammatory cytokines (p<0.01) than non-infected individuals. In summary, we demonstrated that CD8(+) lymphocytes from HIV/HCV-infected patients expressed more CXCR3 and showed greater upregulatory ability upon activation. The atypical CXCR3 expression and enhanced Th-1 cytokine elaboration among coinfected patients could potentially stimulate increased lymphocyte migration during hepatic inflammation.

Organ procurement and transplantation network/united network for organ sharing histocompatibility committee collaborative study to evaluate prediction of crossmatch results in highly sensitized patients.

BACKGROUND: The requirement for a prospective crossmatch limits some organ allocation to local areas. The delay necessitated by the crossmatch restricts the distance across which offers can be made without unduly increasing the ischemia time. A collaborative study involving 14 transplant centers was undertaken by the Organ Procurement and Transplantation Network/United Network for Organ Sharing (OPTN/UNOS) Histocompatibility Committee to evaluate the accuracy with which the detection of unacceptable human leukocyte antigen (HLA) antigens by most advanced solid phase immunoassays can predict crossmatch results. In addition, using actual patients' unacceptable HLA antigens, the number of compatible donors that would have been available from the OPTN deceased kidney donors during 2002 to 2004 were investigated. METHODS: Panel reactive antibodies were performed by conventional or solid phase assays, and crossmatches were performed by cytotoxicity or flow cytometry. Analyses were stratified for T and B cell and by method of identifying unacceptable HLA antigens and crossmatch techniques. RESULTS: Combination of solid phase immunoassays and flow cytometry crossmatches resulted in a higher prediction rates of positive T cell (86.1%-93.5%) and B-cell crossmatches (91%-97.8%). Prediction of negative crossmatches based on different combination of panel reactive antibodies and crossmatch techniques varied from 14.3% to 57.1%. Furthermore, numerous potential compatible donors were identified for each patient, regardless of their ethnicity, in the OPTN database, when predicted incompatible ones were excluded. CONCLUSIONS: The above results showed that with the advent of solid phase immunoassays, HLA antibodies can now be accurately detected resulting in prediction of crossmatch outcome. This should facilitate organ allocation and prevents shipment of organs to distant incompatible recipients.

Cellular immunity impaired among patients on left ventricular assist device for 6 months.

BACKGROUND: Sustained maintenance on left ventricular assist device (LVAD) is associated with an increased frequency of severe infections. Although temporary changes in cellular immunity are seen immediately after implantation, the consequence of sustained LVAD treatment on immunity is unknown. METHODS: In vitro functional and phenotypic markers of T cell activation and 6 month clinical outcome were compared between patients with > or = 6-month LVAD therapy and heart failure control patients. RESULTS: Recipients of LVADs had more infections (45.5% versus 0%; p < 0.05) and mortality (54% versus 16%; p < 0.05) than control patients. T-cell proliferative responses were lower among LVAD recipients than control patients when challenged with phytohemagglutinin (3.4 +/- 4.7 versus 28.5 +/- 19.6; p < 0.01), anti-CD3 (4.3 +/- 4.5 versus 16.4 +/- 17; p < 0.01), and staphylococcal enterotoxin B (7.2 +/- 6.3 versus 26.1 +/- 15.6; p = 0.002). Proliferative hyporesponsiveness among LVAD recipients was not caused by apoptosis (2.6% +/- 2.7% versus 2.7% +/- 2.1%; p = 0.94) or insufficient CD4+ cells (42.1% +/- 11.3% versus 40.2% +/- 7.5%; p = 0.71) relative to control patients. Instead, CD3+ cells from LVAD patients expressed less interleukin 2 (2.5% +/- 1.5% versus 5.2% +/- 3.1%; p = 0.03) and tumor necrosis factor-alpha (6.0% +/- 3.5% versus 25.8% +/- 8.7%; p < 0.001) and more interleukin 10 (5.8% +/- 6.1% versus 2.6% +/- 2.1%; p < 0.05). In addition, suppressive T-regulatory cells were more prevalent in LVAD patients than control patients (12.9% +/- 3.2% versus 1.2% +/- 1.1%; p < 0.001). CONCLUSIONS: Cellular immunity is compromised among long-term LVAD recipients because of a downregulatory cytokine imbalance and emergence of suppressive T-regulatory cells.

Allograft TNFbeta and IL16 polymorphisms influence HCV recurrence and severity after liver transplantation.

Hepatitis C (HCV) recurrence after liver transplantation is universal although severity varies. We explored whether certain donor cytokine gene polymorphisms may be useful markers of susceptibility to severe recurrence. Allograft tumor necrosis factor (TNF) beta and interleukin (IL) 16 gene polymorphisms were correlated with l-yr clinical outcome among HCV+ recipients. Recipients of donor TNFbeta(2,2) (n = 8) experienced less recurrence (50% vs. 71%, P < 0.05), less fibrosis (25% vs. 76%, P < 0.01), and less rejection (25% vs. 71%, P < 0.01) than donor TNFbeta(1,1) (n = 19). Recipients of donor TNFbeta(1,2) (n = 27) demonstrated an intermediate picture with less fibrosis (56%, P < 0.01) and less rejection (37%, P < 0.01) than TNFbeta(1,1). Recipients with donor IL16(TC) (n = 22) showed less recurrence (65% vs. 78%, P = 0.05), less fibrosis (53% vs. 67%, P = 0.06), and less rejection (41% vs. 55%, P = 0.06) than IL16(TT) (n = 32) genotype. Recipients of the combination TNFbeta(2,2)/IL16(TC) donor genotype had the most benign clinical outcome with less recurrence (33% vs. 75%, P < 0.01), no fibrosis (0% vs. 50%, P < 0.001), and fewer rejections (33% vs. 75%, P < 0.01) than donor TNFbeta(1,1)/IL16(TT) genotype. In vitro production of cytokines correlated with genotype. Release of soluble TNFbeta for TNFbeta(1,1) vs. TNFbeta(1,2) and TNFbeta(2,2) was 4803 +/- 2142 pg/mL vs. 5629 +/- 3106 (P = not significant [ns]) and 7180 +/- 3005 (P = ns). Release of soluble IL16 for IL16(TT) vs. IL16(TC) was 437 +/- 86 pg/mL vs. 554 +/- 39 (P = 0.06). In conclusion, allograft TNFbeta and IL16 gene polymorphisms may be useful markers to predict the severity of disease recurrence among HCV+ patients after liver transplantation.

Emergence of IgG3 alloantibody after renal transplantation associated with early graft failure.

In this small study, emergence of complement-fixing alloantibody in the early post-operative period was associated with clinical antibody-mediated rejection that required treatment. It appears that IgG3 alloantibody may be a significant determinant of poorer allograft outcome and failure to respond to PE therapy. Intuitively, it is reasonable that IgG3 may escalate the damage to an allograft over IgG1 alone due to its higher affinity for complement fixation. However, the inability to remove IgG3 by PE filtration was unexpected and may promote refractory rejection. On the other hand, the conversion of alloantibody to IgG2 among the Rescued group may be pivotal to their successful reversal of rejection. The clinical consequences of these atypical isotype presentations upon long-term renal allograft survival are unknown and warrant further study.

Proliferative suppression and class I insufficiency on peripheral blood cells from hepatitis C patients overcome by exogenous cytokines or high-dose mitogen.

An abnormal T cell response to HCV viral infection is speculated to cause viral persistence, although the mechanism(s) is not understood. Using a classical in vitro test of T cell vigor, proliferative responses to PHA were determined in PBLs from 92 HCV+ individuals and 35 healthy noninfected controls. In addition, since HLA antigens modulate proliferation, surface HLA content was measured by quantitative flow cytometry. The proliferative response of cells from HCV+ individuals was lower than that of controls (SI of 91 +/- 70 vs 219 +/- 70, P < .0001). In addition, class I content was underexpressed on cells from HCV+ individuals (4540 +/- 1359 vs 13,180 +/- 5511 MESF units, P < .0001) after 5 days of PHA stimulation. Class II content was also lower than that of controls (89 +/- 17 vs 124 +/- 61 MESF units, P < .0001) after PHA stimulation. Treatment of cells from HCV+ individuals with a high dose of PHA corrected proliferative hyporesponsiveness (P < 0.01) and class I and II insufficiency (P = 0.02). Treatment with exogenous IL-2 or IFN-gamma corrected proliferative reduction (P < 0.01) but not HLA antigen content (P = ns). The results show a biochemical and functional abnormality in PBLs from HCV+ individuals, which may contribute to HCV chronicity.

Comparison of two drug regimens upon clinical outcome among renal transplant recipients with positive flow cytometric crossmatches.

Renal transplant recipients with positive flow cytometric crossmatches (FCXM) face greater risk of early rejection and graft failure. It is clear that the pharmacologic needs of this high risk group have not been identified. We retrospectively compared the impact of two drug regimens upon early rejection and 5 yr actuarial survival among 324 primary cadaveric transplant recipients with positive and negative FCXM. Patients received either Regimen I (OKT3 induction, cyclosporine and steroids) or Regimen II (mycophenolate mofetil with cyclosporine or Prograf). Recipient gender, age, disease etiology, ethnic distribution and cytotoxic panel reactive antibody (PRA) were equivalent between regimens (p=ns). With Regimen I, the incidence of rejection was greater for FCXM positive vs. FCXM negative patients (51 vs. 21%, p=0.001). In contrast, with Regimen II the incidence of rejection for FCXM positive and FCXM negative patients was equivalent (18 vs. 12%, p=ns) and lower than patients treated with Regimen I (p < 0.01). Ethnic variation was only observed with Regimen I in which African Americans with positive FCXM had more rejections than Caucasians (60 vs. 45%, p < 0.05). Five-year actuarial survival was lower for FCXM positive vs. FCXM negative patients treated with Regimen I (40 vs. 75%, p=0.0006) or Regimen 2 (60 vs. 90%, p=0.001). Allograft survival was equivalent (p=ns) among FCXM positive individuals receiving Regimen I or II. However, allograft survival among FCXM negative individuals improved with Regimen II (p < 0.05). Ethnic variation in survival was not observed with either regimen (p=ns).