Designing Metasurfaces for Efficient Solar Energy Conversion

Metasurfaces have recently emerged as a promising technological platform, offering unprecedented control over light by structuring materials at the nanoscale using two-dimensional arrays of subwavelength nanoresonators. These metasurfaces possess exceptional optical properties, enabling a wide variety of applications in imaging, sensing, telecommunication, and energy-related fields. One significant advantage of metasurfaces lies in their ability to manipulate the optical spectrum by precisely engineering the geometry and material composition of the nanoresonators' array. Consequently, they hold tremendous potential for efficient solar light harvesting and conversion. In this Review, we delve into the current state-of-the-art in solar energy conversion devices based on metasurfaces. First, we provide an overview of the fundamental processes involved in solar energy conversion, alongside an introduction to the primary classes of metasurfaces, namely, plasmonic and dielectric metasurfaces. Subsequently, we explore the numerical tools used that guide the design of metasurfaces, focusing particularly on inverse design methods that facilitate an optimized optical response. To showcase the practical applications of metasurfaces, we present selected examples across various domains such as photovoltaics, photoelectrochemistry, photocatalysis, solar-thermal and photothermal routes, and radiative cooling. These examples highlight the ways in which metasurfaces can be leveraged to harness solar energy effectively. By tailoring the optical properties of metasurfaces, significant advancements can be expected in solar energy harvesting technologies, offering new practical solutions to support an emerging sustainable society.

Plasmonic titanium nitride nanomaterials prepared by physical vapor deposition methods

Titanium nitride (TiN) has recently emerged as an alternative to coinage metals to enable the development of integrated plasmonic devices at visible and medium-infrared wavelengths. In this regard, its optical performance can be conveniently tuned by tailoring the process parameters of physical vapor deposition methods, such as magnetron sputtering and pulsed laser deposition (PLD). This review first introduces the fundamental features of TiN and a description on its optical properties, including insights on the main experimental techniques to measure them. Afterwards, magnetron sputtering and PLD are selected as fabrication techniques for TiN nanomaterials. The fundamental mechanistic aspects of both techniques are discussed in parallel with selected case studies from the recent literature, which elucidate the critical advantages of such techniques to engineer the nanostructure and the plasmonic performance of TiN.

Nanoporous Titanium Oxynitride Nanotube Metamaterials with Deep Subwavelength Heat Dissipation for Perfect Solar Absorption

We report a quasi-unitary broadband absorption over the ultraviolet-visible-near-infrared range in spaced high aspect ratio, nanoporous titanium oxynitride nanotubes, an ideal platform for several photothermal applications. We explain such an efficient light-heat conversion in terms of localized field distribution and heat dissipation within the nanopores, whose sparsity can be controlled during fabrication. The extremely large heat dissipation could not be explained in terms of effective medium theories, which are typically used to describe small geometrical features associated with relatively large optical structures. A fabrication-process-inspired numerical model was developed to describe a realistic space-dependent electric permittivity distribution within the nanotubes. The resulting abrupt optical discontinuities favor electromagnetic dissipation in the deep sub-wavelength domains generated and can explain the large broadband absorption measured in samples with different porosities. The potential application of porous titanium oxynitride nanotubes as solar absorbers was explored by photothermal experiments under moderately concentrated white light (1-12 Suns). These findings suggest potential interest in realizing solar-thermal devices based on such simple and scalable metamaterials.

Thermoplasmonic In Situ Fabrication of Nanohybrid Electrocatalysts over Gas Diffusion Electrodes for Enhanced H2O2 Electrosynthesis

Large-scale development of electrochemical cells is currently hindered by the lack of Earth-abundant electrocatalysts with high catalytic activity, product selectivity, and interfacial mass transfer. Herein, we developed an electrocatalyst fabrication approach which responds to these requirements by irradiating plasmonic titanium nitride (TiN) nanocubes self-assembled on a carbon gas diffusion layer in the presence of polymeric binders. The localized heating produced upon illumination creates unique conditions for the formation of TiN/F-doped carbon hybrids that show up to nearly 20 times the activity of the pristine electrodes. In alkaline conditions, they exhibit enhanced stability, a maximum H2O2 selectivity of 90%, and achieve a H2O2 productivity of 207 mmol gTiN-1 h-1 at 0.2 V vs RHE. A detailed electrochemical investigation with different electrode arrangements demonstrated the key role of nanocomposite formation to achieve high currents. In particular, an increased TiOxNy surface content promoted a higher H2O2 selectivity, and fluorinated nanocarbons imparted good stability to the electrodes due to their superhydrophobic properties.

Local Photochemical Nanoscopy of Hot-Carrier-Driven Catalytic Reactions Using Plasmonic Nanosystems

Nanoscale investigation of the reactivity of photocatalytic systems is crucial for their fundamental understanding and improving their design and applicability. Here, we present a photochemical nanoscopy technique that unlocks the local spatial detection of molecular products during plasmonic hot-carrier-driven photocatalytic reactions with nanometric precision. By applying the methodology to Au/TiO₂ plasmonic photocatalysts, we experimentally and theoretically determined that smaller and denser Au nanoparticle arrays present lower optical contribution with quantum efficiency in hot-hole-driven photocatalysis closely related to the population heterogeneity. As expected, the highest quantum yield from a redox probe oxidation is achieved at the plasmon peak. Investigating a single plasmonic nanodiode, we unravel the areas where oxidation and reduction products are evolved with subwavelength resolution (∼200 nm), illustrating the bipolar behavior of such nanosystems. These results open the way to quantitative investigations at the nanoscale to evaluate the photocatalytic reactivity of low-dimensional materials in a variety of chemical reactions.

SARS-CoV-2 Spike protein activates TMEM16F-mediated platelet procoagulant activity

Thrombosis of the lung microvasculature is a characteristic of COVID-19 disease, which is observed in large excess compared to other forms of acute respiratory distress syndrome and thus suggests a trigger for thrombosis that is endogenous to the lung. Our recent work has shown that the SARS-CoV-2 Spike protein activates the cellular TMEM16F chloride channel and scramblase. Through a screening on >3,000 FDA/EMA approved drugs, we identified Niclosamide and Clofazimine as the most effective molecules at inhibiting Spike-induced TMEM16 activation. As TMEM16F plays an important role in stimulating the procoagulant activity of platelets, we investigated whether Spike directly affects platelet activation and pro-thrombotic function and tested the effect of Niclosamide and Clofazimine on these processes. Here we show that Spike, present either on the virion envelope or on the cell plasma membrane, promotes platelet activation, adhesion and spreading. Spike was active as a sole agonist or, even more effectively, by enhancing the function of known platelet activators. In particular, Spike-induced a marked procoagulant phenotype in platelets, by enhancing Ca²⁺ flux, phosphatidylserine externalization on the platelet outer cell membrane, and thrombin generation. Eventually, this increased thrombin-induced clot formation and retraction. Both Niclosamide and Clofazimine blocked this Spike-induced procoagulant response. These findings provide a pathogenic mechanism to explain lung thrombosis-associated with severe COVID-19 infection. We propose that Spike, present in SARS-CoV-2 virions or exposed on the surface of infected cells in the lungs, enhances the effects of inflammation and leads to local platelet stimulation and subsequent activation of the coagulation cascade. As platelet TMEM16F is central in this process, these findings reinforce the rationale of repurposing Niclosamide for COVID-19 therapy.

Nanoporous Titanium (Oxy)nitride Films as Broadband Solar Absorbers

Broadband absorption of solar light is a key aspect in many applications that involve an efficient conversion of solar energy to heat. Titanium nitride (TiN)-based materials, in the form of periodic arrays of nanostructures or multilayers, can promote significant heat generation upon illumination thanks to their efficient light absorption and refractory character. In this work, pulsed laser deposition was chosen as a synthesis technique to shift metallic bulk-like TiN to nanoparticle-assembled hierarchical oxynitride (TiO_xN_y) films by increasing the background gas deposition pressure. The nanoporous hierarchical films exhibit a tree-like morphology, a strong broadband solar absorption (∼90% from the UV to the near-infrared range), and could generate temperatures of ∼475 °C under moderate light concentration (17 Suns). The high heat generation achieved by treelike films is ascribed to their porous morphology, nanocrystalline structure, and oxynitride composition, which overall contribute to a superior light trapping and dissipation to heat. These properties pave the way for the implementation of such films as solar absorber structures.

Syngas Evolution from CO2 Electroreduction by Porous Au Nanostructures

Electrocatalytic reduction of CO₂ recently emerged as a viable solution in view of changing the common belief and considering carbon dioxide as a valuable reactant instead of a waste product. In this view, we herein propose the one-step synthesis of gold nanostructures of different morphologies grown on fluorine-doped tin oxide electrodes by means of pulsed-laser deposition. The resulting cathodes are able to produce syngas mixtures of different compositions at overpotentials as low as 0.31 V in CO₂-presaturated aqueous media. Insights into the correlation between the structural features/morphology of the cathodes and their catalytic activity are also provided, confirming recent reports on the remarkable sensitivity toward CO production for gold electrodes exposing undercoordinated sites and facets.

Solar Thermoplasmonic Nanofurnace for High-Temperature Heterogeneous Catalysis

Most of existing solar thermal technologies require highly concentrated solar power to operate in the temperature range 300-600 °C. Here, thin films of refractory plasmonic TiN cylindrical nanocavities manufactured via flexible and scalable process are presented. The fabricated TiN films show polarization-insensitive 95% broadband absorption in the visible and near-infrared spectral ranges and act as plasmonic "nanofurnaces" capable of reaching temperatures above 600 °C under moderately concentrated solar irradiation (∼20 Suns). The demonstrated structures can be used to control nanometer-scale chemistry with zeptoliter (10^-21 L) volumetric precision, catalyzing C-C bond formation and melting inorganic deposits. Also shown is the possibility to perform solar thermal CO oxidation at rates of 16 mol h^-1 m^-2 and with a solar-to-heat thermoplasmonic efficiency of 63%. Access to scalable, cost-effective refractory plasmonic nanofurnaces opens the way to the development of modular solar thermal devices for sustainable catalytic processes.

Plasmon-Enhanced Photoelectrochemical Water Splitting for Efficient Renewable Energy Storage

Photoelectrochemical (PEC) water splitting is a promising approach for producing hydrogen without greenhouse gas emissions. Despite decades of unceasing efforts, the efficiency of PEC devices based on earth-abundant semiconductors is still limited by their low light absorption, low charge mobility, high charge-carrier recombination, and reduced diffusion length. Plasmonics has recently emerged as an effective approach for overcoming these limitations, although a full understanding of the involved physical mechanisms remains elusive. Here, the reported plasmonic effects are outlined, such as resonant energy transfer, scattering, hot electron injection, guided modes, and photonic effects, as well as the less investigated catalytic and thermal effects used in PEC water splitting. In each section, the fundamentals are reviewed and the most representative examples are discussed, illustrating possible future developments for achieving improved efficiency of plasmonic photoelectrodes.

Accreditation of histocompatibility and immunogenetics laboratories: Achievements and future prospects from the European Federation for Immunogenetics Accreditation Programme

The importance of demonstrating adherence to good practice in the provision of clinical services is well recognised, and there are many legislative and regulatory requirements that aim to ensure that services are appropriately reviewed and certified. Therefore, for regulatory purposes, laboratories must provide assurance of the quality of the services they provide. Additionally in the field of transplantation, where donor organs and stem cells are exchanged across national boundaries, adoption of a common set of standards by laboratories across many different countries is an important factor. The European Federation for Immunogenetics (EFI) Accreditation Programme was established to provide assurance that Histocompatibility & Immunogenetics laboratories providing services for transplantation, transfusion, and disease association testing meet the requirements of the specialty specific EFI standards. The first H&I laboratories achieved EFI accreditation in 1995, and currently there are over 260 EFI accredited laboratories in 36 countries. The programme depends on the voluntary participation of the inspectors, who are all experts in the field of H&I, and who, over the last 22 years, have performed over 1400 onsite inspections of laboratories. Inspection findings show the areas that are most frequently found to be deficient in meeting the requirements of the standards, and this can be used to inform educational and other activities with the aim of improving laboratory compliance with the standards. The EFI standards have been regularly updated to reflect the changes in the field with 19 versions over the last 22 years, and the data from the accreditation programme show how laboratories have changed their practices to incorporate new techniques that support patient care.

[Genotyping in patients affected by HLA-related diseases. App development for diagnostic support.]

HLA typing requests for association studies of immune-mediated diseases are often redundant and inadequate. We designed a series of meta-analyses to evaluate the accuracy of typing and distribution of HLA alleles predisposing to diseases, aiming at developing an app that can help doctors in choosing the most suitable molecular analysis. The first study was on celiac disease (CD) and HLA-DQ in children. We searched all english articles published in the main bibliographic databases up to May 2016. The search strategy has been developed using controlled terms (e.g. MeSH) and free terms. We identified 1885 articles. 1334 abstracts were examined. 46 manuscripts were evaluated, and 13 studies were included in the meta-analysis (740 CD and 943 controls). The risk of developing CD in children with allelic variants encoding the HLA-DQ2.5 and/or HLA-DQ8 molecules has been confirmed. The greatest CD risk resides in carriers of two DQ2.5 molecules, i.e. subjects homozygous for the DQB1*02:01 and DQA1*05 alleles (OR=5.4, 95 % CI=4.1-6.8) compared to any other DQ genotype. Carriers of two DQB1*02:01 (chain β2) alleles and one DQA1*05 (chain α5) allele have the same risk (p=0.8089) of DQ2.5 homozygotes (OR=5.3%, 95 CI=4,1 to 6.5). We found no differences between DQ8/β2 and DQ2.5/DQ8, nor between β2/DQX and DQ2.5/X. We suggest a two-step process: first typing the DQB1*02:01 allele and, in case of a negative result, full typing of HLA-DQ.

Factor-V HR2 haplotype and thromboembolic disease

OBJECTIVES

The objective of this study is to evaluate the prevalence of HR2 polymorphism among patients with pulmonary embolism (PE) and healthy subjects.

BACKGROUND

Polymorphism in the factor V gene named HR2 has been described as a possible risk factor for venous thromboembolism (VTE) development. Contradictive results on this association have been reported.

METHODS

Eighty-five patients admitted for PE and 72 healthy subjects were included in the study. Thrombophilia screening using genetic tests for factor V Leiden (G1691A/Leiden and HR2 haplotype) and other genetic mutations were investigated.

RESULTS

Of 85 patients with PE, 20 (23.53%) carried the HR2 haplotype. Further, a majority of the patients with HR2 haplotype had recurrent venous thrombosis or PE (15 out of 20 patients). The HR2 haplotype was detected in 6 (8.3%) out of 72 healthy subjects. Patients had significantly higher HR2 haplotype frequency than healthy controls (P = 0.001). HR2 carriers had a three-fold increase in risk of developing PE (OR = 3.38, 95% CI = 1.27-8.96, P = 0.011). After adjustment for other tested defects for thrombophilia, HR2 haplotype was associated with increased risk of thromboembolic events (OR = 3.05, 95% CI = 1.11-8.35, P = 0.03). However, after adjustment for sex and age, HR2 polymorphism was no longer associated with the risk of thromboembolic event (OR = 1.22, 95% CI = 0.34-4.38, P = 0.76).

CONCLUSIONS

Our study does not support the notion that factor V HR2 haplotype might be a risk factor for thrombosis despite its high prevalence among patients with PE.

The conundrum of HLA-DRB1*14:01/*14:54 and HLA-DRB3*02:01/*02:02 mismatches in unrelated hematopoietic SCT

Uncertainty still exists on the role of polymorphisms outside the HLA-DRB1 binding site or inside the HLA-DRB3 binding groove in unrelated hematopoietic SCT (HSCT). The ideal model to solve the conundrum consists of the transplants mismatched for HLA-DRB1*14:01/*14:54 and/or for HLA-DRB3*02:01/*02:02. A task force was set up in Italy to recruit transplanted pairs defined as HLA-DRB1*14:01 before 2006, the year crucial for the proper definition of the HLA-DRB1*14:54 allele in molecular biology. Out of 2723 unrelated pairs, 189 transplanted in Italy from 1995 to 2006 were HLA-DRB1*14:01 positive; 103/189 pairs with good historical DNA were retyped for HLA-DRB1*14 and HLA-DRB3 at-high resolution level; 31/103 pairs had HLA-DRB1*14 and/or HLA-DRB3 mismatched; 99/103, having complete clinical data, underwent statistical analysis for OS, TRM, disease-free survival and acute and chronic GvHD. No significant involvement of HLA-DRB1*14:01/*14:54 or HLA-DRB3*02:01/*02:02 mismatches was found, either alone or combined. Our findings suggest that disparities at exon 3 of the HLA-DRB1 gene seem unlikely to influence the outcome after HSCT. The same may be envisaged for HLA-DRB3(*)02:01 and (*)02:02 alleles which, although differing in the Ag binding site, seem unable to modulate an appreciable immune response in an HSCT setting.

Association between protective and deleterious HLA alleles with multiple sclerosis in Central East Sardinia

The human leukocyte antigen (HLA) complex on chromosome 6p21 has been unambiguously associated with multiple sclerosis (MS). The complex features of the HLA region, especially its high genic content, extreme polymorphism, and extensive linkage disequilibrium, has prevented to resolve the nature of HLA association in MS. We performed a family based association study on the isolated population of the Nuoro province (Sardinia) to clarify the role of HLA genes in MS. The main stage of our study involved an analysis of the ancestral haplotypes A2Cw7B58DR2DQ1 and A30Cw5B18DR3DQ2. On the basis of a multiplicative model, the effect of the first haplotype is protective with an odds ratio (OR) = 0.27 (95% confidence interval CI 0.13-0.57), while that of the second is deleterious, OR 1.78 (95% CI 1.26-2.50). We found both class I (A, Cw, B) and class II (DR, DQ) loci to have an effect on MS susceptibility, but we saw that they act independently from each other. We also performed an exploratory analysis on a set of 796 SNPs in the same HLA region. Our study supports the claim that Class I and Class II loci act independently on MS susceptibility and this has a biological explanation. Also, the analysis of SNPs suggests that there are other HLA genes involved in MS, but replication is needed. This opens up new perspective on the study of MS.

HLA genes and surnames show a similar genetic structure in Lombardy: Does this reflect part of the history of the region?

Lombardy, in northern Italy, is the most populated and industrialized Italian region. We attempt to study its genetic structure with two independent sets of data: HLA allele frequencies and surnames. According to our results, it is plausible to deduce that ancient history, more than genetic isolation and drift, may have contributed to the present genetic structure of Lombardy. The hypothesis seems to be confirmed by the results of the cluster analysis of the 11 provinces of the region, which was performed using two different types of markers. Both genes and surnames show approximately the same structure. Not only Celts but also ancient Ligurians (and Etruscans) probably shaped the region into the present three clusters in which the 11 provinces appear to be genetically structured. In particular, an ancient historic, archaeological, and linguistic boundary, along the Adda River, seems to be preserved in present-day Lombardy's population structure.

Distribution of killer cell immunoglobulin-like receptors genes in the Italian Caucasian population

Background

Killer cell immunoglobulin-like receptors (KIRs) are a family of inhibitory and activatory receptors that are expressed by most natural killer (NK) cells. The KIR gene family is polymorphic: genomic diversity is achieved through differences in gene content and allelic polymorphism. The number of KIR loci has been reported to vary among individuals, resulting in different KIR haplotypes. In this study we report the genotypic structure of KIRs in 217 unrelated healthy Italian individuals from 22 immunogenetics laboratories, located in the northern, central and southern regions of Italy.

Methods

Two hundred and seventeen DNA samples were studied by a low resolution PCR-SSP kit designed to identify all KIR genes.

Results

All 17 KIR genes were observed in the population with different frequencies than other Caucasian and non-Caucasian populations; framework genes KIR3DL3, KIR3DP1, KIR2DL4 and KIR3DL2 were present in all individuals. Sixty-five different profiles were found in this Italian population study. Haplotype A remains the most prevalent and genotype 1, with a frequency of 28.5%, is the most commonly observed in the Italian population.

Conclusion

The Italian Caucasian population shows polymorphism of the KIR gene family like other Caucasian and non-Caucasian populations. Although 64 genotypes have been observed, genotype 1 remains the most frequent as already observed in other populations. Such knowledge of the KIR gene distribution in populations is very useful in the study of associations with diseases and in selection of donors for haploidentical bone marrow transplantation.

Comparative analysis of national regulations concerning blood safety across Europe

In October 2001, representatives of 17 European countries (Albania, Bosnia-Herzegovina, Bulgaria, Croatia, Czech Republic, Federal Republic of Yugoslavia, Finland, France, Germany, Greece, Italy, Macedonia, Romania, Slovenia, Spain, Turkey and UK) met in Sarajevo at a course organized by the European School of Transfusion Medicine to discuss their countries' regulations concerning different aspects of the safety of blood transfusion. Results are summarized in tables to facilitate comparisons. Most countries (13/17) have specific transfusion laws and 9/17 have hospital-based systems as opposed to national organizations. Quality assurance is common among investigated countries (14/17). Voluntary associations are responsible for donor promotion in the majority of countries (13/17). Exclusively, voluntary non-remunerated donors are found in 5/17 countries, whereas in the remaining ones, incentives, family replacement and remuneration are mechanisms stimulating blood donation. Medical doctors using official selection criteria are checking donor suitability in virtually all countries, which also perform main microbiological testing. Regulations on good clinical use of blood and derivatives are present in most countries but applied only in some. Although the data presented need to be interpreted with some caution, this preliminary analysis shows that, although some significant differences still exist, the majority of countries studied are moving in the same direction to ensure safety of their blood supply.

Platelet activation during plasma-reduced multicomponent PLT collection: a comparison between COBE Trima and Spectra LRS turbo cell separators

BACKGROUND

The wide diffusion of multicomponent collection in donor apheresis has led to the yielding of different components, such as plasma-reduced platelet-pheresis at high PLT concentration. We investigated whether this collection modality could induce more PLT activation compared to standard plateletpheresis.

STUDY DESIGN AND METHODS

Forty-one plateletpheresis collections (20 Trima and 21 Spectra LRS Turbo v.7.0, COBE) were evaluated. Donor, procedure, and product data were recorded. ADP, collagen, and U46619 (a thromboxane-A2 analog)-induced PLT aggregation was investigated in basal (donor) and final (plateletpheresis unit) samples. The expression of PLT activation marker P-selectin (CD62P) was studied using flow cytometry in basal and final samples. In all cases, P-selectin was investigated in final samples after stimulation with ADP to assess for a possible further release of the antigen. Four additional plateletpheresis procedures were performed in donors from Group A, using the traditional, nonplasma-reduced program.

RESULTS

Plateletpheresis obtained by means of the Trima device showed a lower response to in-vitro induced PLT aggregation and a higher percentage of P-selectin-expressing PLT when compared to products obtained using the Spectra device. Moreover, P-selectin release after ADP stimulation was reduced in plateletpheresis units obtained using the Trima device. These differences disappeared when a nonplasma-reduced collection program was used. In-vivo evaluation did not detect any difference between plateletpheresis obtained by means of the two cell separators.

CONCLUSIONS

Plateletpheresis units obtained by means of multicomponent collection show a higher degree of PLT activation compared to traditional plateletpheresis procedures when high-concentration plasma-reduced products are collected. Randomized clinical studies are needed to assess the real impact of these findings in terms of in-vivo efficacy of plasma-reduced plateletpheresis units.

Lymphocyte subsets in inline filtered packed red blood cell units: comparison between low and high spin procedures

Lymphocyte subsets were determined in 20 packed red blood cell units (PRC) before and after filtration (FPRC) with the Pall Leukotrap RC inline filter system; 10 units were prepared by low spin and platelet rich plasma (PRP) removal (Group A) and 10 with high spin, plasma and buffy-coat (BC) removal (Group B). Flow cytometry was employed for white blood cell (WBC) enumeration and phenotype analysis. Median WBCs in prefiltered units was 2.08 x 10(9) (Group A) vs. 0.8 x 10(9) (Group B) (p < 0.0001). Five Group A and three Group B filtered units had WBC counts above the limit of detection (LD), median values being 25.59 and 3.08 x 10(3), respectively. Whereas CD3+, CD3+CD4+ and CD3+CD8+ lymphocyte subsets were assessable in 20-40% of Group A units, inline filtration of Group B units lowered lymphocytes below the LD of the present study. Post-filtration CD19+ lymphocytes were below the LD in all the 20 units.

An immunogenetic map of Lombardy (Northern Italy)

For this study we consulted the Bone Marrow Donors' Registry of Lombardy (Italy) and analyzed 43937 HLA-A,B phenotypes and 13922 HLA-A,B,DR phenotypes. We estimated the HLA-A,B and HLA-A,B,DR haplotype frequencies via the maximum-likelihood method. We analyzed the genetic structure of the 11 provinces of Lombardy by means of Principal Component Analysis and Correspondence Analysis, and estimated the variety of the different haplotypes at provincial level and the percentage of unique phenotypes at village level. We found 11189 different HLA-A,B phenotypes, 661 different HLA-A,B haplotypes and more than 4000 different HLA-A,B,DR haplotypes. We identified 20 villages, in Western Lombardy, very rich in unique/rare phenotypes. Here we report a formula which allows the identification of a putative donor matched for two haplotypes with a recipient. This result may be of great importance for the genetic study of the population of Lombardy and, even more, for bone marrow transplantation programs.

Bone marrow transplantation for childhood hematological disorders: a global pediatric approach in a twelve year single center experience

One hundred and 43 consecutive pediatric patients (June 1985-December 1996) with at least 18 months of follow-up, were considered: most of the patients (111/143, 77.6%) underwent allogeneic BMT. The median follow-up was 5.7 years. Overall survival and 5 years EFS were 48.6% and 46.9%, respectively. For patients who underwent allogeneic BMT from HLA-identical siblings, the 5 years EFS for ALL was 75% in 1st CR, 60.4% in 2nd CR, 22.3% in > 2nd CR and 86.7% for AML in 1st CR. The EFS for Allo-BMT in "good" and "poor" prognosis patients was 68.6% and 21.8%, respectively (p value = 0.001). Early mortality in Allo-BMT patients was 17.7% between 1985-1990 and 10.3% between 1991-1996. Early treatment-related organ complications occurred mostly in patients who underwent BMT from an unrelated or a mismatched family donor. Late toxicity was evaluated in 57 patients (median follow-up of 82 months): none of the patients complained of significant late cardiac or respiratory dysfunction. With regards to growth, 18/57 patients (31.6%) lost more than two height centile channels. Three cases of thyroid neoplasms were observed. Evaluation of psychosocial functioning, studied in 39 patients who had at least 2 years of follow-up in CR, did not reveal any evident quality of life impairment. The possibility of curing childhood hematological malignancies is based on a global pediatric and multidisciplinary approach. A continuous need to improve results in terms of EFS and quality of life suggests that further multicenter prospective studies should be carried out.

Comparison of plateletpheresis concentrates produced with Spectra LRS version 5.1 and LRS Turbo version 7.0 cell separators

BACKGROUND

The importance of transfusing WBC-reduced blood components is widely recognized, as it reduces the risk of alloimmunization and transfusion-transmitted CMV infections. The latest generation of cell separators allows the collection of WBC-reduced apheresis platelet concentrates (APCs).

MATERIALS AND METHODS

Consecutive APCs (n = 232) were retrospectively evaluated: 163 collected with the Spectra LRS [leukocyte-reduction system] Version 5.1 (Group A) and 69 with the LRS Turbo Version 7.0 (Group B) (both: COBE BCT). Donor peripheral blood count, procedure data, platelet yield, collection efficiency (CE), and residual WBC count in APCs were recorded.

RESULTS

The platelet yield was higher in Group B than in Group A: 5.5 +/- 1.4 versus 4.4 +/- 1.1, p<0.0001; residual WBCs were <5 x 10(6) in 99.4 percent of Group A APCs and in 97.1 percent of Group B APCs. CE was higher in Group B than in Group A: 51.4 +/- 8.7 versus 43.6 +/- 6.3, p<0.0001. Moreover, a correlation between predonation platelet count and platelet yield was observed in both groups. A double product (platelet yield >6.0 x 10(11)) was obtained in 28.9 percent of Group B APCs and in 9.2 percent of Group A APCs.

CONCLUSIONS

The Spectra LRS Turbo version 7.0 release showed a better CE and resulted in a higher platelet harvest than did the LRS version 5.1. High predonation platelet counts allow a higher platelet yield.

Donor organ procurement in the North Italy Transplant program (NITp) in 1994: the beginning of a promising trend?

Donor organ procurement is a world-wide problem. In Italy it is particularly so and the reasons for this are investigated. An overall increase in the number of donors has been noted in 1994 and the first 8 months of 1995, and ways of continuing this encouraging trend should be pursued by improvements in education, legislation, and hospital organization.

HLA-DRB1 compatibility in cadaver kidney transplantation: correlation with graft survival and function

The introduction of genomic HLA-DR typing has stimulated a re-evaluation of the role of HLA-DR compatibility on cadaver kidney transplantation. We retrospectively studied the influence of HLA-DRB1 matching on the survival of 416 patients using univariate and Cox regression analysis as well as its influence on the occurrence of rejection episodes and on creatinine level at the 3rd month in the 198 recipients for whom these data were available. The following parameters were also considered: HLA-A,B compatibility, donor and recipient age, graft number, pre-transplant blood transfusions and panel reactive antibodies (PRA). Twenty-four month graft survival was 100% for transplants with zero mismatches (n = 47), 87.9% for those with one mismatch (n = 191) and 81.3% for those with two mismatches (n = 178). In the Cox model, HLA-DRB1 matching was the most significant variable influencing graft survival (47% of chi 2 P = 0.001), followed by HLA-A,B matching (23%, P = 0.02) and donor age (19%, P = 0.04). Ninety-two percent of the patients with zero mismatches experienced no rejection episodes in the first 3 posttransplant months compared with 62% and 41% of patients with one and two mismatches, respectively. Mean creatinine level (mg/dl) was 1.2, 1.4, and 1.5 in patients with zero, one, and two mismatches, respectively. Should these results be confirmed by prospective studies, HLA-DRB1 compatibility will have to be considered as an organ allocation criterion.

Genomic HLA-DR compatibility in long-term surviving recipients of cadaver kidney transplants

The finding that HLA-DR compatibility assessed by DNA typing correlates with short-term graft outcome better than serology prompted us to study the degree of genomic HLA-DR compatibility on 55 patients with a graft functioning for more than 10 years (group A), compared with 82 patients with more recent transplants regardless of survival (group B). Because adequate blood donor samples were not available for group A long-term survivors, we used donor renal cells obtained by fine needle aspiration biopsy as a source of DNA. We found that in long-term survivors, the distribution of HLA-DR mismatches was significantly different from that observed in group B patients. In particular, whereas a similar proportion of patients with 1 mismatch was seen in both groups, 27.3% of group A patients vs. 6.1% of group B patients had no mismatch, and 23.6% of group A vs. 41.5% of group B patients received transplants with no HLA-DR compatibility (P = 0.001). We also investigated a possible correlation between number of incompatibilities and graft function. Well-matched patients received less steroid pulses than less well-matched recipients, and steroid-resistant rejection episodes were more common among less well-matched recipients. These results suggest a prognostic role of genomic HLA-DR compatibility on long-term success of cadaver kidney transplantation.

A randomized prospective trial comparing cyclosporine monotherapy with triple-drug therapy in renal transplantation

In a prospective trial 151 recipients of renal transplants were randomly assigned to treatment with CsA alone (74 patients) and to low dose of AZA, prednisolone, and CsA (77 patients). At two years, graft survival was 84% for the monotherapy and 90% for the triple therapy. This difference was not statistically significant. The number of rejection episodes was similar in the two groups, but the severity of rejection was significantly worse among the patients on monotherapy. More kidneys were lost because of rejection (6 versus 3), and a higher number of methylprednisolone pulses was used for treating rejection (5.2 +/- 2.3 versus 4.3 +/- 2.9; P = 0.0077). CsA nephrotoxicity episodes were more frequent among patients on monotherapy (23 versus 7; P less than 0.02). Infectious episodes were equally distributed between the two groups. Creatinine clearance was poorer in the monotherapy-treated patients at the third month (42 +/- 16 ml/min versus 48 +/- 15 ml/min; P = 0.02), but no differences were observed between the two groups since the sixth month after transplantation. Many patients on monotherapy required changes in maintenance therapy. In fact, one patient was switched to conventional immunosuppression because of Cremophor-induced anaphylaxis. Another patient who developed Kaposi's sarcoma 4 months after surgery was switched to steroids alone. Excluding 5 patients who lost their grafts a few days after transplantation, only 30 of 74 patients (40%) could be kept without steroids. We conclude that both the therapeutic protocols can give good results in renal allotransplantation; however, monotherapy could create some problems in keeping the balance between drug toxicity and significant immunosuppression. On the contrary, triple therapy is easier to handle, especially in the early posttransplant period when the differential diagnosis between acute rejection and CsA-related nephrotoxicity can be difficult even for a skilled clinician.