Detection of novel HLA alleles by Next-Generation Sequencing in the Croatian population.

The introduction of Next-Generation Sequencing (NGS) methodology in the histocompatibility testing for both allo-HSCT and solid organ transplantation enables the sequencing of all HLA genes, which in turn leads to the discovery of many new HLA alleles. Over the last 3 years, we have identified 28 novel alleles (HLA-A*02:1079, A*03:01:01:112, A*11:01:01:83, A*11:01:01:87, A*24:595, A*68:01:01:15, B*07:02:01:107, B*08:01:01:67, B*08:01:01:69, B*13:02:01:25, B*15:01:82, B*15:18:08, B*18:01:01:76, B*27:02:06, B*27:05:02:34, B*40:06:01:17, B*40:517, C*04:01:01:173, C*04:477, C*05:276, C*07:01:01:130, C*12:03:80, C*12:03:01:62, DQA1*05:01:01:10, DPB1*13:01:07, DPB1*1146:01, DPB1*1456:01 and DPB1*1514:01) using the NGS method. The presented data emphasises the benefits gained by the utilisation of the NGS-based techniques in HLA genotyping but also provides new insight on the HLA polymorphism in the Croatian population.

An intermediate-sized donor registry experience: HLA barriers in matching procedures.

The data enabling the estimation of the possibility of finding a matched unrelated donor (MUD) within a relatively short time is important for the success of hematopoietic stem cell transplantation (HSCT). In the present study, 738 unrelated Croatian patients in the program of unrelated HSCT were retrospectively analyzed for gender matching, donor origin (national or international), the distribution of HLA alleles and haplotypes, as well as for the probability of finding a 9-10/10 MUD. Almost 70% of the patients in our study group had a 10/10 MUD, while among the patients with a 9/10 MUD, a 1st field resolution level mismatched donor was selected for 55.0% of patients. The majority of pairs were HLA-A mismatched (33.8%). A comparison of HLA allele frequencies between two subgroups of patients revealed significant differences for 13 alleles. However, after p value correction, the difference in frequency remained significant only for four alleles; three HLA alleles (B*08:01, C*07:01, and DRB1*03:01) demonstrated a significantly higher frequency among patients with a 10/10 MUD (Pcorr < 0.0001, Pcorr = 0.0096, and Pcorr < 0.0001, respectively), while the B*35:08 allele was significantly more present among patients with a 9/10 MUD (Pcorr = 0.0328). The comparison of the distribution of HLA haplotypes between patients with a 10/10 MUD and patients with a 9/10 MUD showed significant differences for a number of two-locus and three-locus haplotypes, as well as for one five-locus haplotype (HLA-A*01:01~B*08:01~C*07:01~DRB1*03:01~DQB1*02:01), which was significantly more present in the group of patients with a 10/10 MUD. At least one HLA haplotype from the group of non-frequent HLA haplotypes (positions >1000) was carried by patients with a 9/10 MUD. The data obtained by the present study will contribute to a better estimation of the probability of finding a suitable 9-10/10 MUD for Croatian patients in need of HSCT.

HLA Polymorphisms and Clinical Manifestations in IgA Vasculitis.

Studies concerning the genetic background of IgA vasculitis (IgAV), a small-vessel vasculitis occurring predominantly in childhood, have confirmed that the HLA-DRB1 gene showed a strong association with disease susceptibility. The objective was to investigate human leukocyte antigen (HLA) polymorphisms among Croatian patients with IgAV and their influence on disease susceptibility and clinical heterogeneity. Thus, 130 children with IgAV and 202 unrelated healthy individuals were enrolled in the study. Genomic DNA was extracted from whole peripheral blood, and HLA-A, -B, -DRB1 and -DQB1 gene polymorphism analysis was performed. HLA-A*03 (21.4% vs. 12.38%, p = 0.0092), HLA-B*37 (2.9% vs. 0.2%, p = 0.0054) and HLA-DRB1*12 (3.1% vs. 0.7%, p = 0.0216) alleles were significantly more frequent in IgAV patients than in controls. High-resolution typing revealed significantly higher frequency of HLA-DRB1*10:01 and -DRB1*11:03 among IgAV patients with gastrointestinal manifestations of the disease in comparison to controls (p = 0.0021 and p = 0.0301, respectively), while HLA-DRB1*14:01P occurred significantly more often in the group of patients who developed nephritis during the course of the disease (17.5% vs. 4.5%, p = 0.0006). Our results demonstrated that there is an association of HLA-A*03, HLA-B*37 and HLA-DRB1*12 alleles with susceptibility to IgAV in the examined Croatian pediatric population. Studies which aim to determine the HLA profile may contribute to the elucidation of the genetic background of autoimmune diseases, including IgAV.

Serum Fibrinogen and Renal Dysfunction as Important Predictors of Left Atrial Thrombosis in Patients with Atrial Fibrillation.

BACKGROUND: As has been shown previously, patients with atrial fibrillation (AF) who have left atrial thrombus (LAT) also have elevated plasma concentrations of fibrinogen. In this study, we tried to determine if this is the consequence of a genetic trait and whether elevated concentrations of fibrinogen could be used to predict LAT in patients with AF. METHODS: We recruited 181 consecutive patients scheduled for pulmonary vein isolation (PVI) or direct current cardioversion. The primary endpoint was the presence of LAT on transesophageal echocardiography (TOE). We recorded routine clinical and biochemical data as well as the polymorphism type of the fibrinogen gene for the ß chain. To control potentially interfering variables, we performed propensity score matching (PSM). Multivariable and univariable logistic regression models (LRM) were computed using the CHA2DS2-Vasc score, the fibrinogen concentration and creatinine clearance as estimated by the Cockcroft-Gault equation. RESULTS: 60 of 181 patients had LAT as detected by TOE. As expected, patients with LAT had significantly higher concentrations of fibrinogen (3.9 vs. 3.6 g/L); p = 0.01 in the unadjusted analysis. After performing PSM, there were no statistically significant differences between the groups, except for creatinine clearance (79.9 vs. 96.8 mL/min); p = 0.01. There were also no differences regarding the -455 G/A ßfibrinogen polymorphism distribution between the two groups. After constructing the LRM, we found no performance enhancement for the CHA2DS2-Vasc score by adding the fibrinogen concentration or creatinine clearance alone, but when all three variables were put together, there was a significant improvement in LAT prediction (AUC 0.64 vs. 0.72), p = 0.026. CONCLUSION: Our study found no evidence of elevated levels of circulating fibrinogen in patients with LAT or a connection between those levels and the A/A and A positive polymorphism. When used together with renal function markers such as creatinine clearance, plasma fibrinogen concentrations can provide additional power to the CHA2DS2-Vasc score for predicting LAT.

Alternative donor strategy in unrelated hematopoietic stem cell transplantation - outcome with mismatched donors.

PURPOSE: This study retrospectively investigated the association between the level of human leukocyte antigen (HLA) mismatches (MMs), direction of disparities and differences at particular HLA locus on clinical outcomes of hematopoietic stem cell transplantation (HSCT). Investigated outcomes were overall survival (OS) and disease-free survival (DFS), graft-versus-host disease (GvHD), relapse and non-relapse mortality (NRM). PATIENTS AND METHODS: Study cohort included 108 adult patients transplanted between 2011 and 2021 and their 9/10 mismatched unrelated donors (MMUD). All individuals were typed for HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1 loci using Polymerase Chain Reaction-Sequence Specific Primers, PCR-Sequence Based Typing and Next-Generation Sequencing. All statistical analyses were done in the MedCalc software, version 19.2.6. RESULTS: Patients with MMs at HLA-B locus demonstrated worse OS (P â€‹= â€‹0.0440, HR â€‹= â€‹2.00, n â€‹= â€‹20). Absence of HLA-DRB5 was associated with a higher incidence of GvHD (P â€‹= â€‹0.0112, HR â€‹= â€‹1.93, n â€‹= â€‹67). A lower incidence of GvHD was observed in patients with HLA class II MMs compared to patients with HLA class I MMs (P â€‹= â€‹0.0166, HR â€‹= â€‹1.94, n â€‹= â€‹29). Finally, analysis of PIRCHE score (PS) impact revealed that patients with HLA class II PS â€‹> â€‹10 in GvH direction showed higher incidence of GvHD compared to patients with HLA class II PS â€‹< â€‹10 (P â€‹= â€‹0.0073, HR â€‹= â€‹2.01, n â€‹= â€‹55). CONCLUSION: Obtained results undisputedly indicate the necessity to further investigate this matter on a larger patient group, with focus on specific HLA alleles to define precisely priority criteria for selecting the best donor for all patients, thus improving the outcome of HSCT with an MMUD.

The prevalence and genotype of 21-hydroxylase deficiency in the Croatian Romani population.

Objective: Congenital adrenal hyperplasia (CAH) owing to 21-hydroxylase deficiency (21-OHD) is a rare autosomal recessive disorder caused by pathological variants in the CYP21A2 gene. After a high prevalence of classic 21-OHD CAH in the Romani population was reported in the Republic of North Macedonia, we decided to estimate the prevalence of 21-OHD in Croatia and, if high, assess the possible causes and estimate the frequency of particular CYP21A2 variants. Design: Cross-sectional study. Methods: Data from a Croatian 21-OHD genetic database was reviewed, and only Romani patients were included in the study. CYP21A2 genotyping was performed using allele-specific PCR, MLPA, and Sanger sequencing. Results: According to a survey conducted in 2017, Croatia had 22,500 Romani people and six of them had a salt-wasting (SW) form of 21-OHD. All were homozygous for the c.IVS2-13A/C-G pathological variant in intron 2 and descended from consanguineous families belonging to different Romani tribes. The calculated prevalence of 21-OHD in Croatian Romani is 1:3,750, while in the Croatian general population, it is 1:18,000. Three of the six Romani patients originated from two neighboring villages in North-western Croatia (Slavonia County), as well as the seventh patient who is of mixed Romani/Croatian descent and heterozygous for the c.IVS2-13A/C-G pathological variant (not included in the prevalence calculation). Conclusion: A high prevalence of SW 21-OHD in the Croatian Romani population caused by the homozygous cIVS2-13A/C-G pathological variant was found. In addition to isolation and consanguinity, other possible reasons could be the heterozygous advantage of the CYP21A2 gene pathological variant and the bottleneck effect as a result of the Romani Holocaust in World War II.

Various approaches for accessing the influence of human leukocyte antigens disparity in haploidentical stem cell transplantation.

INTRODUCTION: We investigated the association of HLA on clinical outcomes in our cohort of patients in the haplo-HSCT program using the HLAMatchmaker (EM) and PIRCHE score (PS) algorithms. METHODS: The group comprised 64 patients (male = 35-54.7%, female 29-45.3%; median age 43 years) and their related haplo-HSCT donors (male = 30-46.9%, female 34-53.1%). HLA-A/B/C/DRB1/DQB1/DPB1 loci were analyzed. RESULTS: Multivariate analysis of the association between different HLA or patient/donor-related parameters and clinical outcome revealed the following associations with statistical significance: GvHD and HLA class I PS in the GvH direction (p = .0420) and relapse with diagnosis (p = .0163). For OS, the only variable showing a tendency of association was the source of HSCT (p = .0965). CONCLUSION: Combined results of univariate and multivariate analysis suggest that the patients awaiting the selection of the best haplo-HSCT donor could benefit the most from the combination of all three approaches, in cases when a suitable donor can be chosen from a number of potential donors.

HLA-A, -C, -B, -DRB1, -DQA1, and -DQB1 Allele and Haplotype Repertoires in the Albanian Population from Kosovo.

To give new insight into the huge polymorphism of HLA system and supplement the existing data, an analysis of HLA alleles and HLA-A~C~B~DRB1~DQA1~DQB1 haplotype distribution in 124 Albanian individuals from Kosovo was performed. All samples were HLA-typed applying the polymerase chain reaction-sequence specific oligonucleotide probing (PCR-SSOP) method and all ambiguous HLA typing results were additionally confirmed by the standard PCR-Sequence Specific Primers (PCR-SSP) high-resolution protocol. Twenty-two HLA-A, 21 HLA-C, 37 HLA-B, 27 HLA-DRB1, 11 HLA-DQA1 and 14 HLA-DQB1 allele groups were detected. Sixteen out of 172 different six-locus estimated haplotypes were found at a frequency higher than 1.00% with a cumulative frequency of 28.82%. The most prevalent haplotype was found to be HLA-A*02:01~C*07:01~B*18:01~DRB1*11:04~DQA1*05:05~DQB1*03:0(5.2%).A total of 13 haplotypes were observed with higher frequency than in populations reported in HaploStats and The Allele Frequency Net Database. The proposed origin of the most frequent haplotypes reflects a basic Euro-Mediterranean background of Albanians in Kosovo. This is the first report of high-resolution HLA-A~C~B~DRB1~DQA1~DQB1 haplotype distribution among the Albanian population from Kosovo, which provides valuable anthropological data and confirms population-specific characteristics.

Mapping the Human Leukocyte Antigen Diversity among Croatian Regions: Implication in Transplantation.

In the present study, HLA allele and haplotype frequencies were studied using the HLA data of 9277 Croatian unrelated individuals, typed using high-resolution methods for the HLA-A, -B, -C, and -DRB1 loci. The total numbers of observed alleles were 47 for HLA-A, 88 for HLA-B, 34 for HLA-C, and 53 for HLA-DRB1. HLA-A∗02:01 (29.5%), B∗51:01 (10.5%), C∗04:01 (15.8%), and DRB1∗16:01 (10.4%) were the most frequent alleles in the Croatian general population. The three most frequent haplotypes were HLA-A∗01:01~C∗07:01~B∗08:01~DRB1∗03:01 (4.7%), HLA-A∗03:01~C∗07:02~B∗07:02~DRB1∗15:01 (1.7%), and HLA-A∗02:01~C∗07:01~B∗18:01~DRB1∗11:04 (1.5%). Allele and haplotype frequencies were compared between national and regional data, and differences were observed, particularly in the North Croatia region. The data has potential use in refining donor recruitment strategies for national registries of volunteer hematopoietic stem cell donors, solid organ allocation schemes, and the design of future disease and anthropological studies.

The role of HLA in Balkan endemic nephropathy.

Balkan endemic nephropathy (BEN), a progressive chronic tubulointerstitial disease, occurs in the endemic focus of Croatia in a population of about 10,000 inhabitants. One of its most peculiar characteristics is a strong association with upper tract urothelial carcinoma (UTUC). Despite a high number of studies, currently there are insufficient data about the association of BEN and HLA genes. The aim of this study was to investigate the polymorphism of HLA-A, -B, and -DRB1 alleles and haplotypes among BEN patients and to determine whether an association between HLA and BEN exists. In this study, we investigated HLA-A, -B, and -DRB1 alleles and haplotypes in a population of patients with BEN (N = 111) and matched healthy controls (N = 190). All individuals were tested by PCR-SSO and PCR-SSP methods to assess the possible contribution of HLA alleles and haplotypes to the development of/protection from BEN. Our results showed a positive association between the presence of HLA-B*35:02 and DRB1*04:02 alleles and BEN (P = 0.0179 and P = 0.0151, respectively) in contrast to the protective effect of HLA-A*01:01, B*27:05 and B*57:01 alleles (P = 0.0111, P = 0.0330 and P = 0.0318, respectively). Moreover, when BEN patients' HLA haplotypes were compared to controls, two haplotypes were associated with BEN susceptibility among Croatians (HLA-A*02:01~B*08:01~DRB1*03:01 and HLA-A*02:01~B*27:02~DRB1*16:01, P = 0.0064 and P = 0.0023, respectively), while haplotypes HLA-A*02:01~B*27:05~DRB1*01:01 and HLA-A*02:01~B*38:01~DRB1*13:01 each showed a possible protective effect (P = 0.0495). Our results point toward genetic susceptibility to BEN and observed differences in both susceptible/protective HLA profiles indicate the necessity of further studies in order to elucidate the pathogenesis of this disease.

Impact of HLA polymorphisms among cadaveric donors on kidney graft allocation.

This study provides data on HLA-A, -B, and -DRB1 frequencies among 861 end-stage renal disease (ESRD) patients from Croatia and estimates the benefit of the kidney exchange program by comparing HLA distribution and assessing HLA mismatches (MMs) within a group of ESRD patients who received kidney grafts from 707 cadaveric donors (422 from Croatia and 285 from Eurotransplant). Patients positive for HLA-B*07, -B*08, or -B*44 genes more often received a kidney from ET donors, while HLA-DRB1*11 and -DRB1*16 positive patients more frequently received a kidney from CRO donors. ABDR MM 000 was more frequently present in the case of transplantation from ET donors, while MM 222 was significantly more frequent when the donor was from Croatia. Sensitized patients received kidney more frequently from ET donors (P < .0001). A large pool of organ donors with different HLA gene distributions allows for a higher probability of transplantation from HLA highly matched donor.

Detection of novel and confirmation of very rare and rare HLA alleles by next generation sequencing in Croatia.

Routine HLA typing in clinical practice encompassing solid organ and hematopoietic stem cells transplantation programs, disease association typing, volunteer marrow donor typing and population studies, provided a large dataset for studying HLA allele polymorphism in the Croatian population which led to the identification of new, very rare and rare HLA alleles. Over the last 4 years we have identified six new HLA alleles (HLA-A*01:200, A*02:836, A*11:01:01:44, B*08:251, B*18:169 and C*05:46:01:02) and a number of very rare (HLA-B*08:78, DRB1*12:39, DRB1*13:23:02 and DQB1*06:09:04) or rare (HLA-A*24:41, B*39:40:01N, B*51:78:01, DRB1*01:31 and DRB1*14:111) alleles using sequence-based typing methods. The reported data enhance the knowledge about HLA polymorphisms in the Croatian population and provide a foundation for further studies in population genetics.

The MHC gamma block matching: Impact on unrelated hematopoietic stem cell transplantation outcome.

Matching for HLA-A, -B, -C, -DRB1, -DQB1 alleles is the gold standard in hematopoietic stem cell transplantation (HSCT). However, this is often not enough to prevent postransplantational complications. The HLA mismatches (MM) have been associated with higher risk of acute graft versus host disease (GvHD). Gamma block (GB) is located in central HLA region, between HLA-B/C and HLA-DRB/DQB blocks and contains many inflammatory and immune regulatory genes. Single nucleotide polymorphisms (SNPs) within that block can be considered as markers for MHC haplotype matching. Aim of the research was to test whether MM in GB impact the outcome of HSCT in 51 patients transplanted with HLA 10/10 matched unrelated donor. The recipient-donor pairs were typed using PCR SSP kit that detects 25 SNPs within GB. Fifteen out of 51 (29.41%) pairs were GT matched (GT-M) while 36 out of 51 pairs (70.59%) were mismatched (GT-MM). In a univariate analysis, GT-MM was a significant risk factor associated with aGvHD (P = 0.041), although this association was not seen in multivariate analysis. No significant difference in overall survival and relapse occurrence was seen. These results were obtained on a small sample, and it is necessary to further test the possible role of GT matching in unrelated HSCT.

Quantitative polymerase chain reaction technology in chimerism monitoring after hematopoietic stem cell transplantation: One center experience.

Chimerism status evaluation is a routine test performed in post-hematopoietic stem cell transplantation (HSCT) period. The aim of the study was to evaluate a quantitative polymerase chain reaction (qPCR) method (GenDx, Utrecht, the Netherlands) applicability for this purpose. The study included 74 recipient/donor pairs tested for informative markers: median of four and six informative markers was found for patients (related and unrelated donor, respectively). Higher sensitivity of qPCR method was confirmed by analysis of recipient post-HSCT samples (N = 800) among which microchimerism (0.1%-1% recipient DNA) was detected in 21.8% of cases. The ability to detect less than 1% of minor population, as opposed to the short tandem repeat (STR) method for which 1% is the limit, translated into earlier identification of a disease relapse for four patients in our study sample.

HLA Haplotype Association with Celiac Disease in Albanian Pediatric Patients from Kosovo.

Genetic predisposition to celiac disease (CD) is strongly associated with the presence of HLA alleles in the individual genotype encoding HLA-DQ2 and/or HLA-DQ8 heterodimers. The main aim of this study was to analyze the HLA-A, -B, -DRB1, and -DQ allele and five-locus haplotype frequencies in 60 Albanian pediatric CD patients and 124 non-CD children from Kosovo. The most prevalent haplotype in patients was the ancestral AH 8.1 haplotype present in 22.5% of the cases compared to 2.8% of the controls (P < 0.0001). Additionally, two other haplotypes were also overrepresented in patients (HLA-A∗02~B∗50~DRB1∗07~DQA1∗02:01~DQB1∗02:02 and HLA-A∗68~B∗44~DRB1∗07~DQA1∗02:01~DQB1∗02:02). Analysis showed that 95.0% of CD patients and 43.3% of controls were carriers of HLA-DQ2 and/or HLA-DQ8 heterodimers. The most frequent CD-predisposing HLA-DQ haplotypes in patients were HLA-DQ2.5 (46.7%) and HLA-DQ2.2 (11.6%), while the most prevalent genotypes were HLA-DQ2.5/DQX (58.3%) and HLA-DQ2.5/DQ2.2 (20.0%). The frequency of the HLA-DQ8 heterodimer among CD patients (4.2%) compared to the control group (8.1%) was without statistical significance. The given data demonstrate differences in the distribution of HLA haplotypes among Albanian CD patients from Kosovo in comparison to other European and non-European populations, as well as provide additional population data to supplement the thus far undisputed importance of the role of HLA-DQ2 and HLA-DQ8 heterodimers in the development of CD.

Combined association of recipient killer cell immunoglobulin-like haplotype AA and donor HLA-C*07 gene with BK virus associated nephropathy in kidney transplant patients.

Kidney transplant recipient killer cell immunoglobulin-like receptors (KIR) genotype and HLA-C status of their donors have been separately associated with BK virus-associated nephropathy (BKVAN) and BK virus infection. Our aim was to determine whether different combinations of recipients KIR genes and donor HLA-C ligands influence the risk of BKVAN. Retrospective case-control study included 23 recipients with BKVAN and 46 recipients with persistently negative BK virus. Donor HLA-C*07 positivity was associated with lower odds for BKVAN, recipients bearing KIR haplotype AA or lacking any activating KIR genes were more frequent in BKVAN while recipient/donor combination HLA-C*07 negative/KIR AA positive was significantly associated with BKVAN. Our study complements and confirms results from several previously published studies, suggesting potential clinical usefulness.

HLA allele and haplotype diversity in the Croatian population: State of the art.

The aim of this report was to compare our data with data presented in the European Federation for Immunogenetics (EFI) catalogue (version 1.0) and to evaluate whether or not current (CUR) HLA alleles found in the Croatian population fall into the same categories of common (COM) or well-documented (WD) HLA alleles as those listed in the EFI catalogue. Among 237 HLA-A, -B, -DRB1 alleles observed in the Croatian population so far, 181 alleles were observed ≥3 times. According to our criteria, 36 alleles at HLA-A locus, 71 alleles at HLA-B locus and 51 alleles at HLA-DRB1 locus were characterised as CUR in Croatia (COM or WD in EFI catalogue), while 23 local HLA alleles are not listed at all among COM or WD alleles in EFI catalogue.

Human Leukocyte Antigen class II polymorphisms among Croatian patients with type 1 diabetes and autoimmune polyglandular syndrome type 3 variant.

This study included 161 patients: 92 patients had type 1 diabetes (T1D) while 69 patients had a combination of T1D and autoimmune thyroiditis, the so-called autoimmune polyglandular syndrome type 3 variant (APS3v). Those patients, as well as 93 controls, were typed for HLA-DRB1 and -DQB1 genes to assess their possible contribution to the development/protection of T1D with/without autoimmune thyroiditis. Both HLA-DRB1*04 and -DRB1*03 frequencies were significantly higher among T1D and APS3v patients than in controls. The frequencies of HLA-DRB1*11 and -DRB1*15 were lower among T1D patients, while HLA-DRB1*07 and -DRB1*11 occurred significantly less frequently among APS3v patients in comparison to controls. HLA-DQB1*03:01 and -DQB1*03:02 were associated with a higher risk of developing T1D and APS3v; HLA-DQB1*02 was significantly more present among APS3v patients while HLA-DQB1*03:03 was observed with a significantly lower frequency only among T1D patients. HLA-DRB1*03~DQB1*02 and HLA-DRB1*04~DQB1*03:02 were associated with both diseases. The higher frequency of HLA-DRB1*03/DRB1*03 among APS3v patients was the only significant difference in genotype frequency when compared to T1D patients, while high risk (HLA-DRB1*03/DRB1*04) and medium risk genotypes for T1D (HLA-DRB1*04/DRB1*04) occurred with similar frequencies in both patient groups. Although some of the results point toward shared genetic susceptibility of T1D and APS3v, observed differences in both susceptible/protective HLA profiles indicate the necessity of further studies in order to elucidate the pathogenesis of these diseases.

Testicular adrenal rest tumors in congenital adrenal hyperplasia-cross-sectional study of 51 Croatian male patients.

Testicular adrenal rest tumors (TARTs) are common cause of infertility in males with congenital adrenal hyperplasia (CAH). We studied the role of genotype and disease regulation on TART development, their impact on gonadal function, and frequency in 47 21-hydroxylase deficiency (21-OHD) and four 11-hydroxylase deficiency (11-OHD) male patients. Testicular ultrasound (TU), genotype, hormonal measurement in 51, and spermiogram in five patients were performed. TARTs were detected in 14 SW21-OHD and one 11-OHD patient: 1/8 patients aged <7 years (1.8 years old is the youngest), 1/8 patients aged <12 years, 5/17 patients aged <18 years, and in 8/18 adults. All 21-OHD TART patients had exclusively severe mutations of CYP21A2 gene. Poor hormonal control in 8/15 patients with and 12/36 patients without TART indicates correlation of tumor development with poor disease control. None of the TART patients fathered a child. Low inhibin-B was found in 7/15 TART patients. Azoospermia was found in four and oligoasthenozoospermia in one patient. CONCLUSION: TART was detected exclusively in patients with severe CYP21A2 mutations. Disease regulation plays a role in development of TART that impairs testicular function and increases the risk of infertility. Screening for TART by TU is indicated from early childhood. What is Known: • Due to improved diagnostic and therapeutic possibilities, majority of the male patients with congenital adrenal hyperplasia nowadays reach adulthood and screening for long-term complications is becoming more important. • Testicular adrenal rest tumors (TARTs) are common cause of infertility and impaired gonadal function in males with CAH. What is New: • A 1.8-year-old boy described in this paper is the youngest reported patient with TART. • Screening for TART by testicular ultrasound from early childhood, especially in patients with severe CYP21A mutations, is recommended.

HLA-DPB1 matching in unrelated hematopoietic stem cell transplantation program contributes to a higher incidence of disease relapse.

The impact of patient/donor matching for HLA-A, -B, -C, -DRB1 and -DQB1 genes in hematopoietic stem cell transplantation (HSCT) is well-recognized, but typing for additional genes, such as HLA-DPB1, is still controversial. Based on defined T-cell epitope (TCE) groups, all HLA-DPB1 mismatches can be classified as permissive or non-permissive. In this retrospective study we analysed 82 patient-matched unrelated donor (MUD) pairs who underwent HSCT, and explored the impact of HLA-DPB1 matches, permissive and non-permissive mismatches on transplantation outcomes. Patient-MUD pairs matched for HLA-DPB1 alleles in univariate analysis were associated with a significantly higher incidence of disease relapse compared to pairs who were permissive/non-permissive HLA-DPB1 mismatched according to the TCE3 and TCE4 algorithms (P=0.025 and P=0.026, respectively), although the significance was lost in multivariate analysis. The analysis did not reveal any significant influence of HLA-DPB1 alleles on overall survival (OS), non-relapse mortality (NRM) or graft-versus-host disease (GvHD) incidence. In conclusion, our study presents evidence that HLA-DPB1 matching influenced the relapse rate in patients after HSCT so the HLA-DPB1 alleles should be implemented in the MUD search algorithm as a transplantation determinant.