Luovuttajaspesifisten HLA vasta-aineiden merkitys munuaisensiirroissa

Renal transplantation is a preferred choice of treatment for patients who have lost their kidney function due to end-stage renal disease (ESRD). Transplantations in Finland have been centralized to Helsinki University Hospital for both paediatric and adult patients. The results of the kidney transplantation program in Finland have improved over the years and are now excellent, with a one-year graft survival of over 90 %. The major improvements concern short-term problems, and the main challenge today is chronic rejection and long-term survival. The key to further improvements is prevention of chronic rejection and the adequate level of immunosuppression. This thesis was designed to study the prevalence of human leukocyte antigen (HLA) antibodies and to evaluate the relevance of identified donor-specific antibodies (DSA) in the graft outcome. The focus was on graft function, as assessed by the glomerular filtration rate (GFR) and occurrence of delayed graft function (DGF). Another goal for this study was to evaluate various techniques for measuring the immunisation status of a patient and the sensitivity and specificity of different crossmatch techniques with the aim of developing practices in histocompatibility testing. Several cohorts were used in this study. HLA allele frequency, haplotype and panel reactive antibody (PRA) calculations included the data provided by the Finnish Bone Marrow Donor Registry (19807 individuals) and the Finnish Cord Blood Bank (2699 individuals). In addition, 30 immunised patients were included. A total of 235 patients waiting for kidney transplant and 40 deceased donors were used in the prediction of crossmatch outcome. Retrospective clinical studies included 123 pediatric and 771 adult kidney transplant patients. In our study of the Finnish population, a limited amount of allelic diversity was found. For many HLA antigens, practically only one allele is identified. For example, it is extremely unlikely that A3, A11 and A24 are found to be alleles other than A*03:01, A*11:01 or A*24:02, respectively. Also, the most common Finnish HLA haplotypes have very high frequencies when compared to other populations and some haplotypes are unique to the Finnish population. In virtual PRA, HLA antibodies identified against all potential donors were assessed and reported as a PRA% value. This value describes the percentage of donors that present antigens that the patient is immunised against. Due to the uniqueness of the Finnish HLA composition, the use of a calculated population-specific PRA provides a more accurate and reliable estimate of the level of immunisation against available donors Three different crossmatch methods were compared against virtual crossmatch (VXM) results. The flow cytometric crossmatch (FCXM) and Luminex crossmatch (LXM) proved to be the most accurate methods according to the receiver operating characteristic (ROC) analysis, with area under curve (AUC) values of 0.861 and 0.805, respectively. The performance of the complement-mediated lymphocytotoxicity crossmatch (CDCXM) was not as good (AUC: 0.724). There was no clear correlation between the serum samples providing false positive and negative results in each crossmatch technique, which indicates that the main reason for the differences is that each method identifies a different type of antibodies. In the pediatric cohort, HLA antibodies were detected in half of the samples. During the follow-up, one third of the patients presented antibodies against the transplanted kidney. We did not find any association between DSA and poor GFR at the time of sampling or later during the follow-up. In the adult cohort one third (265/771) of the patients were immunised. DSA was detected in 13% (103/771) of the patients at the time of transplantation, even with a negative CDCXM. DGF was more common in patients with DSA than in non-immunised patients (48% and 26%, respectively). DSA against all loci contributed a risk for DGF, but DRB1 seemed to provide the highest relative risk (RR) individually (RR 2.4). Also, the number of DSA and the strength of DSA as measured by cumulative mean fluorescence intensity were significant factors.Munuaisensiirto on hoitomuoto potilaille, joiden omat munuaiset ovat menettäneet toimintakykynsä. Sekä aikuispotilaiden että lapsipotilaiden elinsiirtotoiminta on suomessa keskitetty Helsinkiin. Munuaisensiirtojen tulokset ovat parantuneet ja siirrännäisistä yli 90 % toimii edelleen vuoden kuluttua siirrosta. Etenkin varhaisvaiheen ongelmien hoito on kehittynyt ja tämän päivän haasteet liittyvät erityisesti krooniseen hyljintään ja siirrännäisen pitkäaikaisennusteen parantamiseen. Jotta munuaisensiirtojen tulokset voisivat parantua entisestään, tulisi kiinnittää huomiota kroonisen rejektion varhaiseen tunnistamiseen ja riittävän immunosupression ylläpitämiseen. Tämän väitöskirjatutkimuksen tavoitteena oli tutkia siirrännäiseen kohdistuvien HLA vasta-aineiden (DSA) vaikutusta munuaisensiirron ennusteeseen. Tutkimuksessa munuaisen toimintaa mitattiin munuaissuodoksella ja siirrännäisen viivästyneellä käynnistymisellä. Työssä vertailtiin myös useita potilaan immunisaatiotason mittaamiseen käytettäviä tutkimusmenetelmiä ja pyrittiin määrittämään DSA:lle raja-arvot, jotka ennustavat valkosolujen sopivuuskokeiden tuloksia. Tavoitteena oli kehittää elinsiirtoihin liittyvien kudossopeutuvuustutkimusten käytäntöjä. Kussakin väitöskirjatutkimuksen osatyössä käytettiin omaa tutkimusaineistoaan. Suomen Kantasolurekisterin (19807 liittyjää) ja Istukkaveripalvelun rekisterin (2699) luovuttajien HLA tietoja käytettiin HLA alleelifrekvenssien ja haplotyyppien määrittämiseen. 30 immunisoituneen potilaan vasta-ainetietoja käytettiin laskennallisen PRA:n määrittämiseen. Laboratoriotekniikoita vertailevassa osatyössä oli mukana 235 elinsiirtoa odottavaa potilasta ja 40 luovuttajaehdokasta. Munuaissiirteen ennusteeseen liittyvissä osatöissä oli mukana 123 lapsipotilasta ja 771 aikuispotilasta. Suomalaisessa väestössä havaittiin rajallinen määrä HLA-alleeleita. Yleisimmillä Suomalaisilla HLA-yhdistelmillä eli haplotyypeillä on hyvin korkea esiintyvyys verrattuna muihin väestöihin ja monet haplotyypeistä ovat väestöllemme omaleimaisia. Väestön HLA-jakauman perusteella voidaan määrittää laskennallinen PRA, joka kuvaa potilaan immunisaation tasoa suhteutettuna Suomalaiseen luovuttajajoukkoon. Elinsiirtoa odottavalle potilaalle pyritään löytämään kudostyypiltään sopiva luovuttaja, jota vastaan potilas ei ole immunisoitunut. Todennäköisyys sopivan siirrännäisen löytymiseen voidaan määrittää vertaamalla potilaan HLA-vasta-aineita luovuttajajoukon HLA-tekijöihin. Menetelmävertailussa havaittiin, että virtaussytometrinen- (FCXM) ja Luminex- (LXM) sopivuuskoe korreloivat parhaiten DSA-tulosten kanssa. Sytotoksinen sopivuuskoe yhdistettynä virtuaaliseen sopivuuskokeeseen kuitenkin antaa mahdollisuuden riskiarviointiin ja merkittävästi vähentää siirtoon liittyviä komplikaatioita. Lapsipotilailla tehdyssä tutkimuksessa puolessa tutkituista näytteistä todettiin HLA-vasta-aineita. Siirron jälkeisenä seuranta-aikana kolmanneksella potilaista todettiin HLA-vasta-aineita siirrännäistä kohtaan. Löydökset eivät kuitenkaan ennustaneet munuaissuodoksella mitattua munuaisen toimintakykyä. Aikuispotilailla tehdyssä tutkimuksessa havaittiin, että kolmannes potilaista oli immunisoitunut ennen munuaisensiirtoa ja 13 %:lla vasta-aineet kohdistuivat siirrännäiseen. Näillä potilailla siirrännäisen käynnistymisen viivästyminen onkin kaksi kertaa todennäköisempää

Shorter Cold Ischemia Time in Deceased Donor Kidney Transplantation Reduces the Incidence of Delayed Graft Function Especially Among Highly Sensitized Patients and Kidneys From Older Donors

Background. Long cold ischemia time (CIT) is the most important factor contributing to delayed graft function (DGF) after kidney transplant. Improvements in pretransplant procedures may reduce CIT and improve clinical outcome. Materials and Methods. Pretransplant histocompatibility tests were modernized at our laboratory in 2015, leading to significant decrease of time consumed for these enabling earlier surgery. The effects of this on kidney transplant CIT, DGF, and other clinical outcomes were studied. The study population consisted of 896 consecutive deceased donor kidney recipients, of which 442 patients received a transplant with the old crossmatch and 454 received a transplant with the new crossmatch. Results. CIT shortened from mean 20 hours 6 minutes to 15 hours 52 minutes (P <.001). The incidence of DGF was significantly reduced from 31% to 24% (P = .02). Reduction in the frequency of DGF was more pronounced among the highly sensitized patients (53% to 28%, P = .01) or in patients with pretransplant donor-specific antibodies (50% to 20%, P = .002) and among patients who received kidneys from donors older than 65 years (38% to 27%, P = .04). Conclusions. Process optimization that reduces CIT decreases occurrence of DGF, especially in highly sensitized patients and patients who receive kidneys from older donors.Peer reviewe

IL-10 polymorphisms+434T/C,+504G/T, and-2849C/T may predispose to tubulointersititial nephritis and uveitis in pediatric population

Background Tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU) are likely to be autoimmune diseases. Based on previous studies, adults with isolated idiopathic uveitis have polymorphisms in interleukin 10 (IL-10) and tumor necrosis factor a (TNF-alpha) genes. We aimed to evaluate the presence of IL-10 and TNF-alpha polymorphisms in a nationwide cohort of pediatric TIN/TINU patients. Methods Single nucleotide polymorphisms in IL-10 (+434T/C, +504G/T, -1082G/A, -2849C/T) and in TNF alpha (-308G/A, -238G/A, -857C/T) genes were genotyped in 30 well-defined pediatric patients with idiopathic TIN/TINU syndrome. Control group frequencies for these SNPs were obtained from 393 independent Finnish subjects. Results The homozygous minor allele in IL-10 +434T (rs2222202) and IL-10+504G (rs3024490) was found in all patients with TIN or TINU syndrome while the frequency of these minor alleles in the control population was 44% and 23%, respectively (p <0.001). In IL-10 SNP -2849 (rs6703630) a significant difference was found with genotype TT in all patients (p = 0.004) and in subgroups with TINU syndrome (p = 0.017) and TINU syndrome with chronic uveitis (p = 0.01) compared to reference population. There were no statistical differences in any of the studied TNF-alpha genotypes between TIN/TINU patients and control population. Conclusions A significant difference in the frequency of IL-10+434T and +504G alleles was found between TIN/TINU patients and control population. Genotype -2849TT was more frequently present in patients with TINU syndrome than in the reference subjects. Genetic variation in the inflammatory mediators may predispose to autoimmune nephritis and uveitis.Peer reviewe

Effect of cluster configuration and auxiliary variables on the efficiency of local pivotal method for national forest inventory

201

Sperm Physiological Response to Female Serum—Potential New Insights into the Reproductive Incompatibility Diagnostics

Infertility is assumed to arise exclusively from male- and female-dependent pathological factors. However, recent studies have indicated that reproductive failure may also result from the reproductive incompatibility of the partners. Selection against such incompatibilities likely occurs via female-derived reproductive secretions, including follicular fluid (FF), that mediate gamete-level mate choice towards the sperm of specific males. To facilitate potential development of diagnostic tests for human reproductive incompatibility, we examined whether sperm physiological response to female serum indicate male–female compatibility in the presence of FF. We performed a full-factorial experiment, in which the sperm of 10 males were treated with the FF and serum of 6 healthy females. We found that sperm motility and viability in both biofluids were highly similar and that in 70% of the males, sperm serum treatment predicted male–female compatibility. We also identified male human leucocyte antigen (HLA) alleles and female (FF and serum) anti-HLA antibodies and tested whether the number of allele–antibody matches predict sperm physiological response to female fluids. However, no association was found between measured sperm traits and the number of allele–antibody matches. Overall, the present results may open novel possibilities for the future development of reproductive incompatibility tests and may pave the way towards more accurate infertility diagnostics and treatments

Recurrent Mild Acute Rejections and Donor-specific Antibodies as Risk Factors for Cardiac Allograft Vasculopathy in a National Pediatric Heart Transplant Cohort

Background. Immune-mediated factors such as acute cellular rejections and donor-specific antibodies (DSAs) are risk factors for cardiac allograft vasculopathy (CAV). We studied a national cohort with a unified setting and thorough protocol endomyocardial biopsy (EMB) data for an association between cellular rejections, especially when mild and recurrent, and DSAs with CAV in pediatric heart transplant (HTx) patients. Methods. This is a retrospective, national cohort study of 94 pediatric HTxs performed between 1991 and 2019 and followed until December 31, 2020. Diagnosis of CAV was based on reevaluation of angiographies. Protocol and indication EMB findings with other patient data were collected from medical records. Associations between nonimmune and immune-mediated factors and CAV were analyzed with univariable and multivariable Cox regression analyses. Results. Angiographies performed on 76 patients revealed CAV in 23 patients (30%). Altogether 1138 EMBs (92% protocol biopsies) were performed on 78 patients (83%). During the first posttransplant year, grade 1 rejection (G1R) appeared in 45 patients (58%), and recurrent (>= 2) G1R findings in 14 patients (18%). Pretransplant DSAs occurred in 13 patients (17%) and posttransplant DSAs in 37 patients (39%). In univariable analysis, pretransplant DSAs, appearance and recurrence of G1R findings, and total rejection score during the first posttransplant year, as well as recurrent G1R during follow-up, were all associated with CAV. In multivariable analysis, pretransplant DSAs and recurrent G1R during the first posttransplant year were found to be associated with CAV. Conclusions. Our results indicate that pretransplant DSA and recurrent G1R findings, especially during the first posttransplant year, are associated with CAV after pediatric HTx.Peer reviewe

Integrating biological HLA-DPB1 mismatch models to predict survival after unrelated hematopoietic cell transplantation

</p