Factors affecting physicians' decision to start prehospital blood product transfusion in blunt trauma patients: A cohort study of Helsinki Trauma Registry.

BACKGROUND: Prehospital blood transfusions are increasing as a treatment for bleeding trauma patients at risk for exsanguination. Triggers for starting transfusion in the field are less studied. We analyzed the factors affecting the decision of physicians to start prehospital blood product transfusion (PHBT) in blunt adult trauma patients. STUDY DESIGN AND METHODS: Data of all adult blunt trauma patients from the Helsinki Trauma Registry between March 2016 and July 2021 were retrospectively analyzed. Univariate analysis for the identification of predictive factors and multivariate regression analysis for their importance as predictive factors for the initiation of PHBT were applied. RESULTS: There were 1652 patients registered in the database. A total of 556 of them were treated by a physician-level prehospital emergency care unit, of which by transfusion-capable unit in 394 patients. PHBT (red blood cells and/or plasma) was started in 19.8% of the patients. We identified three statistically highly important clinical triggers for starting PHBT: high crystalloid volume need, shock index ≥0.9, and need for prehospital pleural decompression. DISCUSSION: PHBT in blunt adult trauma patients is initiated in ~20% of the patients in Southern Finland. High crystalloid volume need, shock index ≥0.9 and prehospital pleural decompression are associated with the initiation of PHBT, probably reflecting patients at high risk for bleeding.

Low titer group O whole blood and risk of RhD alloimmunization: Rationale for use in Finland.

BACKGROUND: Prehospital low-titer group O whole blood (LTOWB) used for patients with life-threatening hemorrhage is often RhD positive. The most important complication following RhD alloimmunization is hemolytic disease of the fetus and newborn (HDFN). Preceding clinical use of RhD positive LTOWB, we estimated the risk of HDFN due to LTOWB prehospital transfusion in the Finnish population. STUDY DESIGN AND METHODS: We collected data on prehospital transfusions in Tampere and Helsinki University Hospital areas. Using the mean of reported alloimmunization rates in trauma studies (24%) and a higher reported rate representing trauma patients of 13-50 years old (42.7%), we estimated the risk of HDFN and extrapolated it to the whole of Finland. RESULTS: We estimated that in Finland, with the current prehospital transfusion rate we would see 1-3 cases of severe HDFN due to prehospital LTOWB transfusions every 10 years, and fetal death due to HDFN caused by LTOWB transfusion less than once in 100 years. DISCUSSION: The estimated risk of serious HDFN due to prehospital LTOWB transfusion in the Finnish population is similar to previous estimates. As Finland routinely screens expectant mothers for red blood cell antibodies and as the contemporary treatment of HDFN is very effective, we support the prehospital use of RhD positive LTOWB in all patient groups.

In vitro comparison of cold-stored whole blood and reconstituted whole blood.

BACKGROUND AND OBJECTIVES: Cold-stored whole blood (CSWB) is increasingly used in damage control resuscitation. Haemostatic function of CSWB seems superior to that of reconstituted whole blood, and it is sufficiently preserved for 14-21 days. To provide evidence for a yet insufficiently studied aspect of prehospital CSWB use, we compared in vitro haemostatic properties of CSWB and currently used in-hospital and prehospital blood component therapies. MATERIALS AND METHODS: Blood was obtained from 24 O RhD positive male donors. Three products were prepared: CSWB, in-hospital component therapy (red blood cells [RBCs], OctaplasLG and platelets 1:1:1) and prehospital component therapy (RBCs and lyophilized plasma 1:1). Samples were drawn on days 1 and 14 of CSWB or RBC cold storage. On day 14, platelet concentrates at their expiry (5 days) were used for 1:1:1 mixing. Conventional clotting assays, rotational thromboelastometry, thrombin formation and platelet function were assessed. RESULTS: Haemoglobin, platelet count, fibrinogen and coagulation factor levels remained closest to physiological in CSWB. Factor VIII activity decreased markedly by day 14 in CSWB. The decline in platelet function was prominent in CSWB. However, CSWB on day 14 yielded physiological EXTEM MCF, suggesting haemostatically sufficient platelet function. Despite haemodilution and lower coagulation factor levels, in-hospital component therapy was haemostatically adequate. Prehospital component therapy formed the weakest clots. Thrombin formation potential remained comparable and stable in all groups. CONCLUSION: Current prehospital component therapy fails to offer the clotting potential that CSWB does. CSWB and current in-hospital 1:1:1 component therapy show similar haemostatic potential until 14 days of storage.

Scandiatransplant acceptable mismatch program-10 years with an effective strategy for transplanting highly sensitized patients.

In March 2009, the Scandiatransplant acceptable mismatch program (STAMP) was introduced as a strategy toward improving kidney allocation to highly sensitized patients. Patients with a transplantability score ≤ 2% are potential candidates for the program. Samples are analyzed and acceptable antigens (HLA-A, B, C, DRB1, DRB3/4/5, DQB1, DQA1, DPB1, DPA1) are defined by the local tissue typing laboratory and finally evaluated by a steering committee. In the matching algorithm, patients have the highest priority when the donor's antigens are all among the recipient's own or acceptable HLA antigens. In the period from 2009 to 2020, we have transplanted 278 highly sensitized kidney patients through the program. The graft survival of the STAMP patients was compared with 9002 deceased donor kidney-transplanted patients, transplanted in the same time period. The 10-year graft survival was 73.4% (95% CI: 60.3-90.0) for STAMP and 82.9% (95% CI: 81.6-84.3) for the reference group. (p = .2). In conclusion, the 10-year allograft survival demonstrates that the STAMP allocation algorithm is immunological safe. The program is continuously monitored and evaluated, and the introduction of matching for all HLA loci is a huge improvement to the program and demonstrate technical adaptability as well as clinical flexibility in a de-centralized organization.

HLA-selected platelets for platelet refractory patients with HLA antibodies: a single-center experience.

BACKGROUND: Platelet refractoriness due to HLA immunization represents a problem in transfusion management of thrombocytopenic hematology patients. Refractory patients can be managed by HLA-selected platelet transfusions, but the optimal matching strategy is debated and how the degree of HLA mismatch influences transfusion outcome is poorly studied. STUDY DESIGN AND METHODS: We studied 32 hematology patients who received 142 matched platelet units between 2007 and 2016. Four matching strategies were compared: 1) genomic HLA typing at the two digit level, performed using polymerase chain reaction-sequence-specific oligonucleotide probing; 2) serologic "eplet score" calculated using HLAMatchmaker; 3) cross-matching using lymphocyte cytotoxicity; and 4) matching based on donor-specific antibody (DSA) specificity, determined using Luminex. A 1-hour corrected count increment (CCI) of more than 7.5 × 109 /L was considered a successful response. RESULTS: Selection of platelets with either a complete HLA match or an acceptable HLA mismatch based on genomic typing and DSA information, each predicted 86% successful transfusion responses. For HLA-mismatched transfusions, the eplet score correlated with CCI and the fraction of successful transfusions, but less well compared to DSA matching. Cytotoxic crossmatching was least predictive. For transfusions across one to four DSAs, the antibody reaction strength correlated with the 1-hour CCI, but many transfusions were successful despite the presence of DSA. CONCLUSION: A complete HLA-A and -B match or an acceptable mismatch based on DSA should guide identification of donors. Still, transfusions across DSAs are often successful, emphasizing that the presence of DSA is necessary but not sufficient for platelet clearance.

Renal function after combined liver-kidney transplantation: A longitudinal study of pediatric and adult patients.

It has been proposed that the liver protects the kidney in CLKT. However, few studies have examined long-term renal function after CLKT and contrasted renal function of CLKT patients to KT patients beyond one year after transplantation. We studied long-term renal function of CLKT patients and compared renal function of CLKT patients to KT patients between one and five years after transplantation. Patients who underwent CLKT between 1993 and 2011 were included (n = 34; 11 children and 23 adults). Ninety-six (27 children and 69 adults) KT patients were selected as controls. GFR was estimated (eGFR) and measured (mGFR) with 51 Cr-EDTA clearance. Mean mGFR was 63 at one and 70 at ten years after pediatric CLKT. Mean eGFR was 75 at one and 50 at ten years after adult CLKT. Difference in mean mGFR between pediatric CLKT and KT patients was 8 (95% CI -7 to 23) and 11 (95% CI -4 to 26) at one and five years after transplantation, respectively. Difference in mean eGFR between adult CLKT and KT patients was 8 (95% CI -5 to 20) and 1 (95% CI -10 to 12) at one and five years after transplantation, respectively. Longitudinal changes in GFRs were somewhat similar in CLKT and KT patients in both age-groups but pediatric CLKT patients had on average higher GFRs than pediatric KT patients. In long-term follow-up, renal function remains stable in pediatric CLKT patients but declines in adult CLKT patients.

BK polyomavirus viremia and antibody responses of pediatric kidney transplant recipients in Finland.

BACKGROUND: BKPyV is an important cause of premature graft failure after KT. Most clinical studies describe BKPyV infection in adult KT patients. We studied the prevalence of post-transplant BKPyV viremia, serology, and graft function in pediatric KT recipients. METHODS: Forty-six pediatric patients transplanted between 2009 and 2014 were followed up for BKPyV DNAemia by plasma PCR for median 2.3 (range: 1-6) years. BKPyV-specific antibodies were retrospectively analyzed using virus-like particle ELISA. GFR was measured annually by 51 Cr-EDTA clearance, and serum samples were screened for DSAs by Luminex assay. RESULTS: BKPyV viremia was demonstrated in nine patients at a median of 6 months post-KT. Early BKPyV viremia at 3 months post-KT associated with decreased concomitant GFR and tendency for decreased subsequent graft function. Three of nine patients with BKPyV viremia developed DSA, all against class II antigens. PyVAN developed to four patients and responded to judicious reduction in IS. One graft was lost later due to ABMR. BKPyV-IgG was found in 18 of 31 patients (58%) tested at transplantation, and seven recipients seroconverted after transplantation with a significant increase in IgG levels with IgM. Finally, BKPyV-IgG was detectable in 31 of 40 patients (78%) at the end of the study. CONCLUSIONS: Post-transplant BKPyV viremia in pediatric KT patients may alter graft function and contribute to progression of chronic allograft injury. BKPyV-IgG predicts past exposure. Low or absent BKPyV-specific antibody levels were seen pretransplant in 42% of tested patients, but were not predictive of prolonged replication or poor outcome.

Anemia and low-grade inflammation in pediatric kidney transplant recipients.

BACKGROUND: Anemia and low-grade inflammation are reported to be associated with impaired long-term graft outcome in renal transplant (RTx) recipients. In this study, hemoglobin (Hb) and inflammation marker levels were correlated with measured glomerular filtration rate (GFR) in 128 pediatric RTx recipients over a median follow-up period of 10 years. METHODS: Serum levels of erythropoietin (EPO), hepcidin-25, high-sensitivity C-reactive protein (CRP) (hsCRP) and interleukin-6 (IL-6) were analyzed by enzyme-linked immunosorbent assays, and GFR was analyzed by 51Cr-EDTA clearance. RESULTS: The median levels of Hb (115 g/L), hsCRP (0.4 mg/L) and IL-6 (1.4 pg/mL) and the median erythrocyte sedimentation rate (ESR; 19 mm/h) remained stable after the first post-operative year. However, approximately half of the patients had a normocytic, normochromic anemia, and one-third had elevated levels of hsCRP (>1 mg/L) and ESR (>25 mm/h), indicating continuous low-grade inflammation. Low Hb levels preceded increased fibrosis in protocol biopsies taken at 1.5 and 3 years after transplantation and preceded decreased GFR by several years. Hb levels showed an inverse correlation with EPO levels (r = -0.206, p = 0.038) and ESR (r = -0.369, p < 0.001), but not with hepcidin-25, hsCRP or IL-6 levels. The levels of the major inflammatory markers IL-6 and hsCRP did not show a significant correlation with GFR at either the early maintenance phase or later. In the multivariable analysis, low Hb levels performed better than any other marker with respect to predicting concomitant and subsequent GFR. CONCLUSIONS: Anemia, but not elevated inflammatory indices, was associated with poor concomitant and subsequent graft function during a 10-year follow-up in pediatric RTx patients.

Donor-specific antibodies after pediatric liver transplantation: a cross-sectional study of 50 patients.

The role of donor-specific HLA antibodies (DSAs) after pediatric liver transplantation (LT) is inadequately established. We conducted a cross-sectional study on the prevalence of DSAs and their association with liver histology and biochemical variables after pediatric LT. Serum samples were drawn for HLA antibody analyses from 50 patients (76% of 66 eligible patients) operated on at age <18 years between 1987 and 2007 with a median of 10.0 (interquartile range 4.0-16.4) years after deceased donor LT. Mixed and single-antigen beads with Luminex were used for HLA antibody screening and detection. A mean fluorescence intensity (MFI) value of 1000 was used for positive cutoff. Twenty-six patients (52%; 95% confidence interval (CI) 39% to 65%) had DSAs. In 22 (85%) patients, DSAs were against class II HLA antigens with a mean (standard deviation) MFI of 13,481 (4727). The unadjusted prevalence ratio for portal inflammation in DSA-positive compared to DSA-negative patients (n = 47; 9/24 vs. 1/23) was 8.6 (95% CI 1.6 to 50.9). Laboratory values at the time of study were comparable between DSA-positive and DSA-negative patients. In conclusion, approximately half of patients studied had DSAs after pediatric LT. Portal inflammation was associated with DSA positivity although the wide confidence interval around the ratio estimate warrants cautious interpretation.

[Changes in consumption of blood products in Finland from 2007 to 2014]. / Verivalmisteiden kulutuksen muutokset Suomessa vuosina 2007-2014.

The Finnish Red Cross Blood Service (FRCBS) collects and distributes all cellular blood products in Finland. The use of red cells in Finland follows neither the aging of the Finnish population nor morbidity. The use of red blood cells has diminished 34% during the last 20 years and half of this decrease has taken place during the last three years. Use of platelet preparations per inhabitant in Finland clearly exceeds European median. An enhanced IT support for the blood supply chain is needed to maximize the effectiveness of use of blood products.

Late hepatic artery thrombosis after pediatric liver transplantation: a cross-sectional study of 34 patients.

Hepatic artery thrombosis (HAT) after liver transplantation (LT) increases patient morbidity and mortality. Early HAT is considered to occur within the first month after LT, whereas late HAT occurs after the first month. Few studies have addressed late HAT after LT, especially in pediatric patients. Between 1987 and 2007, 99 patients (age < 18 years) underwent deceased donor LT. Thirty-four of 66 eligible patients (52%) underwent magnetic resonance imaging (MRI) according to protocol. On the basis of MRI findings, the patients were grouped as those who experienced late HAT and those who did not. Additionally, potential risk factors for late HAT were analyzed retrospectively. P values were adjusted for multiplicity. The median age at LT was 1.7 years [interquartile range (IQR) = 1.0-9.6 years], and the median follow-up time at MRI was 9.5 years (IQR = 4.0-16.4 years). Late HAT was diagnosed in 15 of the 34 patients [44%, 95% confidence interval (CI) = 29%-61%] undergoing MRI and in 3 of these patients with angiography preceding MRI. Ultrasonography revealed late HAT in 6 of these 15 patients with a sensitivity of 40% (95% CI = 20%-64%). The donor/recipient weight ratio remained significantly higher for the patients with late HAT versus the patients without late HAT after P values were adjusted (5.4 versus 1.9, P = 0.03). No marked differences were observed in laboratory or liver histology parameters between the groups. In conclusion, late HAT is common after pediatric LT. The donor/recipient weight ratio was higher for patients with late HAT, and this was attributable to the lower weight of the recipients. No salient features of late HAT were observed with respect to laboratory or histological parameters, at least in terms of our study's cross-sectional period.

Very Low Frequency of Pathological Findings in One-year Protocol Biopsies of Uneventful Standard Risk Kidney Transplant Recipients: Results From the Nordic Protocol Biopsy Study.

Background: The clinical significance of kidney transplant protocol biopsies has been debated. We studied the frequency of borderline changes and T cell-mediated rejection (TCMR) in 1-y protocol biopsies in standard risk kidney transplant recipients. Methods: Consecutive non-HLA-sensitized recipients of kidney transplants between 2006 and 2017, who underwent a protocol biopsy at 1 y in 2 national transplant centers were studied retrospectively (N = 1546). Donor-specific HLA antibodies (DSAs), graft function (plasma creatinine), and proteinuria were measured at the time of 1-y protocol biopsy. The occurrence of subclinical acute TCMR (i2t2v0 or higher) or borderline changes suspicious of TCMR (i1t1v0 or higher) in the protocol biopsy was studied, together with frequency of findings causing changes in the composite score iBox. Results: Subclinical acute TCMR was detected in 30 of 1546 (1.9%) of the protocol biopsies, and borderline or TCMR in 179 of 1546 (12%). Among patients with no history of acute rejection, and no proteinuria or DSA, TCMR was detected in only 1 of 974 (0.1%) and borderline or TCMR in only 48 of 974 (4.9%) patients at 1 y. In the absence of proteinuria (<30 mg/g, or equivalent as measured with a negative dipstick proteinuria) or DSA, or history of acute rejection, only 50 of 974 (5.1%) biopsies showed any lesions significant for the iBox score. Conclusions: The likelihood of pathological findings in 1-y protocol biopsies in non-HLA-sensitized patients without previous immunological events is low. Clinical usefulness of protocol biopsies seems limited in these patients.

A Retrospective Study of Long-Term Outcomes in 16 ABO-Incompatible Deceased Donor Pediatric Liver Transplants from a National Transplant Center at Helsinki University Hospital, Finland, 1987-2022.

BACKGROUND The use of ABO-incompatible liver transplants (ABO-ILTs) from deceased donors has become more common due to the shortage of available donor livers and increased transplant waiting times. This retrospective study from a national transplant center at Helsinki University Hospital, Finland, aimed to assess the long-term outcomes of ABO-incompatible deceased donor pediatric liver transplants between 1987 and 2022. MATERIAL AND METHODS Sixteen (9.5%) of the 169 pediatric liver transplantations were ABO-ILTs. The median age at transplantation was 5.0 (0.5-15.4) years. Reasons for ABO-ILTs were acute liver failure (18.75%), malignancy (12.5%), small body size and long waiting time (25%), and other reasons (43.75%). The median post-transplant follow-up time was 147 (0.72-353) months. Patient and graft survival and occurrence of surgical complications were compared to ABO-identical transplants, and anti-ABO antibody titers were analyzed. RESULTS The 1-, 3-, and 5-year patient survivals were comparable between the ABO-I and ABO-compatible groups, being 81.3%, 73.9%, and 73.9% (ABO-I) and 87.5%, 82.5%, 77.9% (ABO-compatible), respectively. Three patients with ABO-ILTs died of sepsis and multiorgan failure during the first 3 months after transplantation. The occurrence of biliary complications and early vascular thrombosis (<30 days after transplantation) did not differ significantly between recipients with an ABO-ILT vs ABO-compatible liver graft. CONCLUSIONS The findings from this study support findings from previous studies that outcomes after ABO-incompatible liver transplants in children were comparable to outcomes from ABO-identical liver transplants.

[Graduate schools under change--case report on a Finnish national graduate school]. / Tutkijakoulut murroksessa--esimerkkinä Valtakunnallisen kliinisen tutkijakoulun tohtoriohjelma.

The independent status of Finnish doctoral programmes is changing as the funding is being transferred to the universities. The role of universities is correspondingly becoming stronger. The universities will establish a new organization for research training. We wanted to elucidate the significance of the nationally networked Finnish national graduate school of clinical medicine for research training. As an example we used the doctoral programme of the national graduate school of clinical medicine. The quality of research training as well as the continuation of training organizations created by nationally networked doctoral programmes must be guaranteed.

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.

Scandiatransplant Exchange Program (STEP): Development and Results From an International Kidney Exchange Program.

Background: Kidney transplant candidates may be incompatible with their intended living donors because of the presence of antibodies against HLA and/or ABO. To increase the possibility of finding an acceptable kidney donor for these patients, the Scandiatransplant Exchange Program (STEP) program within Scandiatransplant was launched in 2019. Methods: This is a retrospective review of our experiences from the first 4 y of the STEP program, including details about the match runs, performed transplantations, and recipient outcomes within the program. Results: During 2019-2022, 11 match runs and 4 reruns were performed. In total, 114 pairs and 6 anonymous donors participated in these match runs. Fifty-one pairs (45%) participated in 1 match run, 31 pairs (27%) participated in 2 match runs, and 32 pairs (29%) participated in ≥3 match runs. Seventy-two individuals (63%) participated because of HLA incompatibility, 19 (17%) because of ABO incompatibility, and 7 (6%) because of both HLA and ABO incompatibility.Forty percent of the patients enrolled in the program underwent transplantation. In total, 49 transplantations have so far been performed within the program, and 46 (94%) of the recipients had a functioning kidney graft at follow-up in February 2023. Conclusions: The STEP program offers sensitized patients an enlarged pool of living donors and a chance of a compatible international living donor, resulting in an increased number of total transplantations. Currently, STEP is one of the largest transnational kidney exchange programs and has improved the situation for patients waiting for kidney transplantation in Scandiatransplant.

Endoscopic surveillance and primary prophylaxis sclerotherapy of esophageal varices in biliary atresia.

OBJECTIVES: Evidence-based recommendations on endoscopic screening and prophylactic treatment of esophageal varices in patients with biliary atresia (BA) are scarce. We assessed the efficiency of endoscopic surveillance and risk factors of esophageal varices and associated upper gastrointestinal bleeding. METHODS: A total of 47 consecutive children with BA and portoenterostomy underwent yearly endoscopies and prophylactic injection sclerotherapy of esophageal varices between 1987 and 2009. The median follow-up was 1.7 years (range 0.5-18.9) and overall 2-year survival 71%. Disease characteristics, clearance of jaundice, laboratory tests reflecting liver function and hypersplenism, as well as sonographic signs of portal hypertension were related to endoscopic findings and bleeding episodes. RESULTS: Grade 2 to 3 varices developed with similar frequency after failed (18/28, 64%) and successful portoenterostomy (10/19, 53%) in 28 patients. Following failed portoenterostomy, esophageal varices were encountered significantly earlier (8 [4-23] vs. 19 [4-165] months, P = 0.004), and they reappeared after eradication more often (16/16 vs. 4/10, P = 0.001). Varices bled only after failed portoenterostomy (13/28 vs. 0/19, P < 0.001). Increased serum bilirubin concentration >40 µmol/L at 3 months after portoenterostomy was a risk factor of upper gastrointestinal bleeding (odds ratio [OR] 17, 95% confidence interval [CI] 1.7-175, P = 0.017). CONCLUSIONS: In future studies as well as clinical surveillance of BA patients' varices, successful and failed portoenterostomy patients should be approached as separate groups with divergent prognoses. After failed portoenterostomy, surveillance should start early, for example, at 6 months.

Donor-specific HLA antibodies and graft function in children after renal transplantation.

BACKGROUND: The presence of circulating donor-specific human leukocyte antigen antibodies (HLA-DSA) has been associated with chronic antibody-mediated rejection, leading to progressive graft dysfunction and poor graft survival.The aim of this study was to investigate the incidence and significance of HLA-DSA in paediatric renal transplantation(RTx) patients. METHODS: A total of 294 post-transplant serum samples from 123 RTx patients were retrospectively analysed for HLA antibodies. Positive samples were further tested for HLADSA by a Luminex Single Antigen bead assay. The antibody findings were correlated to measured glomerular filtration rate(GFR) and clinical outcome. RESULTS: HLA antibodies were detected in half of the routine samples (140/294) taken 1 month to 10 years after RTx, and 40% (62/140) of these were HLA-DSA. Overall, one-third(42/123) of the patients had HLA-DSA, which mostly(65%) reacted against class II antigens. Detection of HLADSA was not associated with poor GFR at the time of sampling, and no exceptional deterioration of GFR after the HLA-DSA detection was noted in individual patients regardless of the antibody level. The presence of HLA-DSA in the first 2 years posttransplantation was not associated with poorer graft function later on. CONCLUSION: Detection of HLA antibodies is common in children after RTx, and this finding, as such, does not predict any deterioration of graft function.

Mismatches in Gene Deletions and Kidney-related Proteins as Candidates for Histocompatibility Factors in Kidney Transplantation.

Introduction: The genomic mismatch level between donor and recipient may be associated with the risk of rejection and graft survival. We determined the association of genome-level matching with acute rejection in deceased-donor kidney transplantation. Methods: The study cohort consists of 1025 recipient-donor pairs transplanted in a single center from 2007 to 2017 in Helsinki. The associations between the sums of whole-genome missense variant mismatches and missense mismatches in transmembrane, secretory, and kidney-related proteins, with acute rejection were estimated using Cox model. In addition, we analyzed 40 deletion-tagging variants using Cox model. Results: The association analysis between mismatch sums of kidney-related proteins and acute rejection resulted in an unadjusted hazard ratio (HR) of 1.15 (95% confidence interval [CI], 1.01-1.30; P = 0.029) and adjusted HR of 1.13 (95% CI, 0.99-1.28; P = 0.071). In deletion analysis, a mismatch in rs7542235 genotype GG tagging a homozygous deletion at the complement factor H-related (CFHR), proteins locus, predisposed to acute rejection with an unadjusted HR of 3.10 (95% CI, 1.53-6.29; P = 0.002) and adjusted HR of 2.97 (95% CI, 1.46-6.05; P = 0.003). Conclusion: In conclusion, analyses of genome-level mismatches may be useful tools in prediction of transplantation outcome. The relative importance differs between populations, because we found evidence for CFHR deletion but could not replicate the finding of previously reported LIMS1 deletion.