Synthesis of Ruthenium Complex Containing Conjugated Polymers and Their Applications in Dye‐Sensitized Solar Cells

The synthesis of two ruthenium terpyridine complexes containing conjugated polymers is reported and their application as photosensitizers in dye‐sensitized solar cells (DSSC) was studied. The polymers were synthesized by the palladium‐catalyzed coupling reaction between the ruthenium complex monomer and the fluorene‐based comonomer. One polymer was functionalized with carboxylic acid groups on the main chain, which strongly facilitate the anchorage of polymer dye molecules on the electrode surface. DSSCs based on TiO₂ nanoparticles and nanotubes were fabricated. It was found that the ruthenium complexes played an important role in the photosensitization process, and the power conversion efficiencies measured were in the order of 0.1%. Annealing of TiO₂ nanotubes in ammonia gas flow did not result in significant improvement in cell performance.

     

Terminal complement inhibition decreases antibody-mediated rejection in sensitized renal transplant recipients

Sensitized renal transplant recipients with high levels of donor-specific alloantibody (DSA) commonly develop antibody-mediated rejection (AMR), which may cause acute graft loss or shorten allograft survival. We examined the efficacy of terminal complement inhibition with the humanized anti-C5 antibody, eculizumab, in the prevention AMR in renal transplant recipients with a positive crossmatch against their living donor. The incidence of biopsy-proven AMR in the first 3 months posttransplant in 26 highly sensitized recipients of living donor renal transplants who received eculizumab posttransplant was compared to a historical control group of 51 sensitized patients treated with a similar plasma exchange (PE)-based protocol without eculizumab. The incidence of AMR was 7.7% (2/26) in the eculizumab group compared to 41.2% (21/51) in the control group (p = 0.0031). Eculizumab also decreased AMR in patients who developed high levels of DSA early after transplantation that caused proximal complement activation. With eculizumab, AMR episodes were easily treated with PE reducing the need for splenectomy. On 1-year protocol biopsy, transplant glomerulopathy was found to be present in 6.7% (1/15) eculizumab-treated recipients and in 35.7% (15/42) of control patients (p = 0.044). Inhibition of terminal complement activation with eculizumab decreases the incidence of early AMR in sensitized renal transplant recipients (ClincalTrials.gov number NCT006707).     

Clinical and histopathologic features of antibody‐mediated rejection among pediatric renal transplant recipients with preformed vs de novo donor‐specific antibodies

Preformed and de novo donor specific antibodies (pDSA and dnDSA) are risk factors for ABMR. This study compares the effects of pDSA vs dnDSA in pediatric kidney transplant recipients. Sixteen pediatric patients with biopsy‐proven ABMR were evaluated. Strong DSA (MFI >10 000) was recorded at transplant, rejection, and follow‐up. DSAs with the highest MFI were termed iDSAs. Allograft biopsies were scored according to Banff 2013 criteria. Seven of 16 (44%) patients had pDSA at transplant; 9 (56%) developed dnDSA. Patients with pDSA developed ABMR earlier (median = 63 vs 1344 days, P = .017), while patients with dnDSA were more likely to have strong Class II iDSA (100% vs 28%, P = .009). Viral infection or non‐adherence was more common in patients developing dnDSA (88.8% vs 28.6%, P < .01). Pathology in those with pDSAs demonstrated worse transplant glomerulitis (g score 1.57 ± 0.98 vs 0.56 ± 0.73, P = .031); however, those with dnDSAs exhibited higher C4d+ ABMR (P = .013). Patients developing dnDSAs showed ABMR later post‐transplant with predominance of HLA‐Class II iDSAs. Inadequate immunosuppression likely contributes to dnDSA formation. Patients with no DSA who have unprotocolized decreases in immunosuppression should be screened for dnDSA as it could lead to early intervention and potentially better outcomes.     

COMMENTS

Testicular germ cell tumors (TGCTs) are the most common cancer affecting young men. TGCT is a polygenic trait and genes that control susceptibility for TGCT development have not yet been identified. The 129/Sv inbred strain of mice is an important experimental model to study the genetics and development of TGCTs. We review several novel approaches that were developed to study the susceptibility of TGCTs in the 129/Sv mouse model and its application in humans. These approaches showed that several spontaneous and engineered mutations interact with 129/Sv-derived susceptibility genes to enhance or suppress susceptibility; two of these mutations (Ter and Trp53) revealed novel linkages for susceptibility genes in sensitized polygenic trait analysis. Linkage analysis with a chromosome substitution strains suggests that as many as 100 genes control susceptibility. Bilateral TGCTs result from the coincidental occurrence of unilateral tumors. These results highlight the important contributions that this mouse model can make to studies of TGCT susceptibility in humans.     

Highly Successful and Low-Cost Desensitization Regime for Sensitized Living Donor Renal Transplant Recipients

10–30% of dialysis population awaiting renal transplantation is sensitized. Present desensitization protocols use intravenous immune globulins, rituximab, and plasmapheresis in various combinations; however, these regimens are unaffordable by many in developing countries. We tried desensitization with mycophenolate mofetil and plasmapheresis. Methods. Patients with high PRA titre (≥50%) or positive crossmatch (>10%) were treated with MMF for a month before proposed transplant and were given five sittings of plasmapheresis. Results. 11 of 12 patients had normalization of PRA/crossmatch with this regimen and were successfully transplanted. One patient lost the graft due to graft vein thrombosis, and two patients died within three months after transplant due to septicemia and pulmonary embolism, respectively, with a functioning graft. No patient, including the two who died, developed clinical rejection over a mean follow-up of 10 months (range 1–16 months). Mean serum creatinine at last follow up was 1.1 mg/dL (range 0.9–1.3 mg/dL). Conclusions. Though the number of patients studied is small, we feel that highly sensitized patients awaiting living donor renal transplant should be tried on this simple and cost-effective regime before transplant. The more aggressive and expensive approaches incorporating IVIg and rituximab should be used only if this relatively low-cost regime is unsuccessful.     

The effectiveness of the combination of rituximab and high‐dose immunoglobulin in the immunomodulation of sensitized kidney transplant candidates

Kidney transplantation faces many challenges not the least of which is the presence of pre‐formed HLA antibodies. At our institution, we have used a combination of methods to immunomodulate sensitized patients. Most recently, this has been attempted with a combination of immunoglobulin (IVIG) and rituximab (Rituxan; Genetech, CA, USA). A total of 31 patients were followed for up to one yr following treatment with IVIG (2 gm/kg on day 1 and day 30) and rituximab (1 g – day 15). Antibody levels were followed serially at designated time points via solid‐phase single‐antigen beads (SAB) method (One Lambda, Inc., Canoga Park, CA, USA). Concentration of antibodies was based on median fluorescence intensity (MFI). The majority of patients had both class I and class II antibodies (79%). Our results showed that this protocol appeared to be patient and antibody specific. The most pronounced MFI reduction in antibodies occurred within the 30‐ to 100‐d period post‐treatment. Calculated panel‐reactive antibodies decreased but rebound tended to occur by 104 d after antibody MFI nadir. Because of this rebound, it can be inferred that the patients did not show a durable increase in their potential for transplantation. The search for a more effective method to immunomodulate patients continues.     

Five‐Year Outcomes in Living Donor Kidney Transplants With a Positive Crossmatch

Renal transplant candidates with high levels of donor‐specific anti‐HLA antibodies have low transplantation rates and high mortality rates on dialysis. Using desensitization protocols, good short‐term outcomes are possible in “positive crossmatch kidney transplants (+XMKTx)”, but long‐term outcome data are lacking. The aim of the current study was to determine actual 5‐year graft outcomes of +XMKTx. We compared graft survival and the functional and histologic status of 102 +XMKTx to 204 ?XMKTx matched for age and sex. Actual 5‐year death‐censored graft survival was lower in the +XMKTx group (70.7% vs. 88.0%, p < 0.01) and chronic injury (glomerulopathy) was present in 54.5% of surviving grafts. Graft survival was higher in recipients with antibody against donor class I only compared with antibody against class II (either alone or in combination with class I) (85.3% vs. 62.6%, p = 0.05) and was similar to ?XMKTx (85.3 vs. 88.0%, p = 0.64). Renal function and proteinuria ranged across a wide spectrum in all groups reflecting the different histological findings at 5 years. We conclude that when compared to ?XMKTx, +XMKTx have inferior outcomes at 5 years, however, almost half of the surviving grafts do not have glomerulopathy and avoiding antibodies against donor class II may improve outcomes.     

Intravenous human immunoglobulin treatment of serum from HLA-sensitized patients in kidney transplantation

Objective: Intravenous immunoglobulin (IVIG) products are known to have beneficial immunomodulatory effects on several inflammatory and autoimmune disorders. These effects could be attributed to a different inhibitory action on complement factors, but other mechanisms could be implicated, e.g., immunocomplexes development and/or anti-idiotypic antibodies. Positive results on the reduction of anti-Human Leukocyte Antigens (HLA) antibodies in highly sensitized patients have also been found. The present study focuses on the effect of IVIG on the reduction of Panel Reactive Antibody level and crossmatch positivity in sensitized patients awaiting kidney transplantation. Methods: The study was performed adapting an in vitro assay on sensitized patients’ sera in waiting list for kidney transplantation. Sera of twelve highly sensitized patients were evaluated for the cytotoxicity inhibition after 10% IVIG treatment. Results: A reduction of anti- HLA antibody levels was observed in 75% (9/12) of treated patients in vitro, while 25% (3/12) resulted unresponsiveness. Particularly, our data showed a significantly higher Panel Reactive Antibody reduction for T lymphocytes (p?p?Conclusions: In this study, we have used an in vitro assay to investigate susceptibility to desensitization with IVIG treatment of sensitized patient sera. These findings reveal that the variable effect of IVIG on reducing Panel Reactive Antibody in our immunized patients could be attributed to a different inhibitory action on complement, likely due to the type and the titre of anti-HLA antibodies.     

冻融抗原致敏的树突细胞对裸鼠人卵巢癌移植瘤治疗作用的研究

目的 :研究冻融抗原致敏的树突细胞 (DC)对裸鼠人卵巢癌移植瘤的治疗作用。方法 :联合应用粒性白细胞与巨噬细胞集落刺激因子 (GM CSF)及白介素 4 (IL 4 )从正常足月产妇分娩后新生儿脐血中培养出DC ,以人卵巢癌细胞系 3AO细胞冻融抗原激活DC ,测定其诱导的细胞毒性T淋巴细胞 (CTL)对 3AO的杀伤活性 ;CTL预防性接种于裸鼠皮下 ,观察裸鼠人卵巢癌移植瘤的发生率 ,以DC激活的CTL治疗裸鼠人卵巢癌移植瘤并观察治疗效果。结果 :体外抗原冲击致敏的DC能显著刺激T淋巴细胞增殖 ,其诱导的CTL对细胞系 3AO具有显著的杀伤作用 ,在效靶比为 4 0 :1、2 0 :1、10 :1、5 :1时 72h杀伤率平均分别为 90 .1%、67.4 %、4 0 .4 %、17.8%。DC激活的CTL能预防裸鼠人卵巢癌移植瘤的发生 (预防组 16.6% ,对照组 10 0 % ,P <0 .0 0 1) ,并能抑制移植瘤生长 ,对照组、治疗组移植瘤的大小分别为 (5 .6± 1.1)cm3 、(2 .7± 0 .78)cm3 (P <0 .0 1)。结论 :人卵巢癌细胞冻融抗原体外冲击致敏的DC可作为一种抗癌疫苗在免疫治疗卵巢癌患者中发挥重要作用