HLA-G Genotype Research Articles

HLA-G gene polymorphisms as predictors of survival in colorectal cancer: A unified machine learning approach

ObjectivesHuman leukocyte antigen (HLA-G) is a potent molecule involved in immune-tolerance. Here, we investigated the contribution of HLA-G gene polymorphisms (14 bp Ins/Del and +3142C/G) for accurate prediction of colorectal cancer (CRC) overall survival (OS) status. Our study presents a comprehensive investigation of the prognostic value of HLA-G genotypes and haplotypes in predicting OS status in 266 Tunisian patients with CRC. MethodsWe used a machine learning (ML)-based framework described below: (1) A dimensionality reduction approach was used to examine evidence of an association between HLA-G genotypes and OS status. (2) Decision-tree ML models were used to explore the performance of the HLA-G genotype as a relevant contributing feature to accurately predict OS status. ResultsHLA-G polymorphisms were highly predictive of OS status when a random forest classifier was used. The HLA-G 14 bp Ins/Del polymorphism outperformed the HLA-G + 3142C/G polymorphism as a predictor of OS. The Del/Del genotype was associated with worse OS and the G/G genotype was associated with favorable OS. The InsC haplotype predicted a favorable prognosis, and the DelG haplotype predicted a worse OS. The combined prediction demonstrated, with 100 % precision and high accuracy, that Del/Del genotype associated with key clinical features, can efficiently predict poor OS. The results were evaluated through an external validation process to ensure their reliability. ConclusionsWe demonstrated the potential of HLA-G gene polymorphisms as robust candidate biomarkers to predict OS in CRC patients. Research on the HLA-G gene present a promising avenue for developing an innovative decision-making tool to identify candidates for personalized therapeutic interventions.

HLA-G Alleles Impact the Perinatal Father-Child HPV Transmission.

The host factors that influence father-to-child human papillomavirus (HPV) transmission remain unknown. This study evaluated whether human leukocyte antigen (HLA)-G alleles are important in father-to-child HPV transmission during the perinatal period. Altogether, 134 father-newborn pairs from the Finnish Family HPV Study were included. Oral, semen and urethral samples from the fathers were collected before the delivery, and oral samples were collected from their offspring at delivery and postpartum on day 3 and during 1-, 2- and 6-month follow-up visits. HLA-G alleles were tested by direct sequencing. Unconditional logistic regression was used to determine the association of the father-child HLA-G allele and genotype concordance with the father-child HPV prevalence and concordance at birth and during follow-up. HLA-G allele G*01:01:03 concordance was associated with the father's urethral and child's oral high-risk (HR)-HPV concordance at birth (OR 17.00, 95% CI: 1.24-232.22). HLA-G allele G*01:04:01 concordance increased the father's oral and child's postpartum oral any- and HR-HPV concordance with an OR value of 7.50 (95% CI: 1.47-38.16) and OR value of 7.78 (95% CI: 1.38-43.85), respectively. There was no association between different HLA-G genotypes and HPV concordance among the father-child pairs at birth or postpartum. To conclude, the HLA-G allele concordance appears to impact the HPV transmission between the father and his offspring.

The Impact of HLA-G and HLA-E Polymorphisms on CMV Reinfection in Liver Transplant Recipients.

Cytomegalovirus (CMV) reinfection in transplant patients has been associated with graft loss and decreased patient survival. In this regard, the HLA-G molecule has the immunomodulatory characteristic and its soluble isoforms have important roles in immunity to viruses. The 14bp insertion/deletion polymorphism impacts HLA-G mRNA stability. Regarding the HLA-E molecule, two nonsynonymous alleles, HLA-E*0101, and HLA-E*0103 are different in their functions including the affinity of the relative peptide. To explore the possible link between HLA-G and HLA-E polymorphisms with CMV reinfection among liver transplant recipients (LTRs). In this study, a total of 140 liver transplantations were performed; of which 70 CMV-reactivated LTRs and 70 CMV non-reactivated ones were recruited. The cut-off value of CMV DNA was determined to be 100 copies/mL. PCR evaluated different genotypes for HLA-G and ARMS-PCR for HLA-E*0101 and *0103. Neither the HLA-G genotypes (-14 bp/-14bp and +14bp/+14 bp homozygous genotypes with the p-values: 0.43, and 0.13, respectively +14 bp⁄-14 bp heterozygous genotype with p-value: 0.49) nor the HLA-E genotypes (HLA-E*0101/0103, HLA-E*0101/0101, and HLA-E*0103/0103 with the p-values: 0.152, 0.249, and 0.391, respectively) had any association with CMV reinfection in the LTRs. No difference was observed in the HLA-E and HLA-G genotype frequencies between our studied groups. Further studies are needed to explore other genetic variations and evaluate soluble HLA-G and HLA-E levels in the transplant population.

The association of HLA-G polymorphism with oral and genital HPV infection in men

The host genetic factors that influence the natural history of human papillomavirus (HPV) infection in men are not well known. Our aim was to evaluate the role of human leukocyte antigen (HLA)-G polymorphism in oral and genital HPV infection in men. Altogether, 130 men from the Finnish Family HPV Study, with a 6-year follow-up, were included in the analyses. HLA-G alleles were tested by direct sequencing. Oral, urethral, and semen samples were collected and analyzed for 24 different HPV genotypes. Unconditional logistic regression was used to determine associations between HLA-G alleles and genotypes with HPV infection and its outcomes. Overall, eight different HLA-G alleles were identified with 15 different HLA-G genotype combinations. The most common HLA-G allele among the men was G*01:01:01 (86.2%, n = 112) followed by G*01:01:02 (36.2%, n = 47). Allele G*01:01:02 showed to be protective against any- and high-risk (HR) oral HPV (OR range of 0.20–0.24, 95% CI range of 0.06–0.85). Men having allele G*01:01:01 showed a reduced risk for incident (OR 0.30, 95% CI 0.11–0.84) and persistent (OR 0.24, 95% CI 0.08–0.69) oral infections. Allele G*01:01:03 was associated with increased risk for urethral HR-HPV infections (OR 4.94, 95% CI 1.34–18.27). Among self-reported demographic data, genotype G*01:01:01/01:01:03 was associated with an increased risk for oral warts (OR 8.00, 95% CI 1.23–51.89) and allele G*01:03:01 increased the risk of pollen and/or animal allergy (OR 13.59, 95% CI 1.57–117.25). To conclude, HLA-G polymorphism in men largely impacts the outcome of an oral HPV infection and seems to associate with self-reported allergies.

HLA-G polymorphism impacts the outcome of oral HPV infections in women

BackroundHuman leukocyte antigen (HLA)-G may have an important role in the natural history of human papillomavirus (HPV) infection. Our aim was to evaluate the role of HLA-G in the outcome of genital and oral HPV infections in women.MethodsAnalyses included 306 women from the Finnish Family HPV-study and were followed-up for six years. Genital and oral samples were tested for 24 different HPV types with multiplex HPV genotyping. HLA-G alleles were determined through direct DNA-sequencing. Unconditional logistic regression was used to determine the associations between HLA-G genotypes and HPV infection outcomes.ResultsTen HLA-G alleles were identified. Most common HLA-G genotypes were the wild type G*01:01:01/01:01:01 (31.3%) followed by G*01:01:01/01:01:02 (26.8%). G*01:01:01/01:01:01 genotype was associated with increased risk of oral HPV infections by any HPV type or single-type with OR = 1.86 (95% CI 1.14–3.04, P = 0.01) and 2.22 (95% CI 1.14–3.71, P = 0.02), respectively. G*04:01+ allele and the G*01:01:01/01:04:01 genotype both protected from any and single oral HPV infections; OR = 0.46 (95% CI 0.23–0.89, P = 0.02) and 0.53 (95% CI 0.23–0.97, P = 0.03), respectively. G*01:01:02/01:04:01 genotype increased significantly the risk of infertility and its treatments, with respective OR = 5.06 (95% CI 1.22–21.02, P = 0.03) and OR = 9.07 (95% CI 1.22–39.50, P = 0.03). Both HLA-G alleles and genotypes showed several significant associations with the outcomes of oral HPV infections, but none of them had any impact on the outcomes of genital HPV infections in these women.ConclusionsThe host HLA-G genotypes appear to impact the outcomes of oral HPV infections in women but have little if any effect on genital HPV status or infection outcomes.

Analysis of HLA-G long-read genomic sequences in mother\u2013offspring pairs with preeclampsia

Preeclampsia is a pregnancy-induced disorder that is characterized by hypertension and is a leading cause of perinatal and maternal–fetal morbidity and mortality. HLA-G is thought to play important roles in maternal–fetal immune tolerance, and the associations between HLA-G gene polymorphisms and the onset of pregnancy-related diseases have been explored extensively. Because contiguous genomic sequencing is difficult, the association between the HLA-G genotype and preeclampsia onset is controversial. In this study, genomic sequences of the HLA-G region (5.2 kb) from 31 pairs of mother–offspring genomic DNA samples (18 pairs from normal pregnancies/births and 13 from preeclampsia births) were obtained by single-molecule real-time sequencing using the PacBio RS II platform. The HLA-G alleles identified in our cohort matched seven known HLA-G alleles, but we also identified two new HLA-G alleles at the fourth-field resolution and compared them with nucleotide sequences from a public database that consisted of coding sequences that cover the 3.1-kb HLA-G gene span. Intriguingly, a potential association between preeclampsia onset and the poly T stretch within the downstream region of the HLA-G*01:01:01:01 allele was found. Our study suggests that long-read sequencing of HLA-G will provide clues for characterizing HLA-G variants that are involved in the pathophysiology of preeclampsia.

Examining extended human leukocyte antigen-G and HLA-F haplotypes: the HLA-G UTR-4 haplotype is associated with shorter time to pregnancy in an infertility treatment setting when both female and male partners are carriers

To study the impact of extended human leukocyte antigen (HLA)-G and HLA-F haplotypes on time to pregnancy as measured by the number of treatment cycles in a cohort of couples in infertility treatment. Prospective cohort study of couples undergoing infertility treatment. University hospital. A cohort of 127 couples and four single women in infertility treatment. Next-generation sequencing of the HLA-G gene and genotyping of three HLA-F locus single-nucleotide polymorphisms (SNPs). Extended HLA-F.HLA-G haplotypes, HLA-G promoter haplotypes and HLA-G 3'UTR haplotypes and their association with time to pregnancy as measured by number of treatment cycles until achievement of pregnancy with a live birth. Linkage disequilibrium between HLA-G variations and three HLA-F locus SNPs that impact time to pregnancy. The effect of the HLA-G 3'UTR haplotype, UTR-4, was significantly increased, or modified, if the partner was a carrier compared to being a noncarrier. Extended HLA-F.HLA-G haplotypes, HLA-G promoter haplotypes, and the HLA-G 14 bp indel of the female partners were not associated with time to pregnancy. However, a trend for an association of the HLA-G 14bp insertion allele with a higher frequency of miscarriage than the 14bp deletion allele was observed. Certain HLA-G variations are in linkage disequilibrium with three HLA-F locus SNPs that influence time to pregnancy. HLA-G UTR-4 is significantly associated with time to pregnancy in couples undergoing infertility treatment. The findings could imply that both male and female HLA class Ib genetics have clinical relevance in reproduction.

Evaluation of Plasma Levels of Soluble HLA-G and HLA-G Genotypes in Kidney Transplant Recipients

In the field of transplantation, expression of HLA-G, a nonclassical HLA molecule with immunosuppressive functions and limited gene polymorphism, is considered beneficial for graft acceptance; various studies have aimed to demonstrate this role in transplantation. Recently, in other clinical conditions, it has been observed that insulin resistance was associated with HLA-G14bpins/del polymorphism, the most studied regulatory polymorphism of this molecule. In the present study, plasma levels of the soluble form of HLA-G (sHLA-G) were analyzed in kidney transplant recipients (n = 103) with different HLA-G14bpins/del genotypes. In a group of 26 recipients, sHLA-G was detected before and after transplantation (1 year) to evaluate early variations. In 77 recipients, sHLA-G was detected after transplantation (3-24 years) and correlated with occurrence of long-term post-transplant morbidity (diabetes mellitus, hyperlipidemia, hypertension, obesity, etc.). MethodsLevels of sHLA-G were measured in plasma with an enzyme-linked immunosorbent assay; HLA-G14bpins/del and HLA-G+3142C>G genotypes were assessed using direct polymerase chain reaction. ResultsPlasma levels of sHLA-G significantly decreased during the first year after transplantation (P = .019); no significant correlations were found with genotypes or early post-transplant events. Lower levels of sHLA-G were found in recipients with post-transplant diabetes mellitus or obesity carrying the HLA-G14bpins/ins (P = .006 and P = .003, respectively) or HLA-G+3142G/G genotypes. ConclusionsA complex modulation of HLA-G, which includes both immunologic and metabolic effects, could affect the risk for long-term post-transplant morbidity in kidney transplant recipients. Associations of HLA-G, diabetes, and obesity deserve to be investigated by deeply exploring HLA-G regulatory variants.

Non-classical human leukocyte antigen class I in Tunisian children with autism.

Autism spectrum disorders (ASD) are one of the most common childhood morbidities characterized by deficits in communication and social skills. Increasing evidence has suggested associations between immune genes located in the human leukocyte antigen (HLA) complex and etiology of autism.In this study, we investigated whether the non-classical class I HLA-G, -E, and -F polymorphisms are associated with genetic predisposition to autism in Tunisia. We aimed to find a correlation between HLA-G genotypes and soluble HLA-G (sHLA-G) levels. We have analyzed the HLA-G, -E, and -F genotypes of 15 autistic children and their parents. DNA typing of HLA class I genes was performed using PCR-SSP and PCR-RFLP methods. Also, we evaluated the serum levels of HLA-G (1 and 5) by a validated ELISA technique in autistic probands and their parents.No association was found between any polymorphism and autism in the study subjects. Additionally, we found no correlation between sHLA-G1 and sHLA-G5 and autism. Also, no significant difference in sHLA-G testing in parents and offspring was found. However, parents carrying [GG] genotype presented a higher sHLA-G levels than those carrying ([CC]+[GC]) genotypes (p = 0.037).From this preliminary study, we conclude that the investigated polymorphisms of HLA-G, -E, and -F genes did not lead to autism susceptibility in Tunisian children. However, the CGTIGA haplotype was found to be associated with the disease.

The genetic contribution of HLA-E*01:03 and HLA-E*01:03-G*01:01 to Posner-Schlossman syndrome in southern Chinese.

The polymorphisms of classical HLA-Ia and HLA-II loci have been associated with Posner-Schlossman syndrome (PSS) in the southern Chinese population. However, the associations of non-classical HLA-Ib (e.g., HLA-E and HLA-G) loci with PSS have not been reported for in the southern Chinese population. This study aimed to evaluate the associations of the HLA-E and HLA-G loci with PSS in a southern Chinese Han population group. Ninety-seven unrelated patients with PSS and 90 ethnically matched control subjects were recruited from the Shenzhen Eye Hospital in China. The full-length sequences of HLA-E and HLA-G genes were amplified by long-range high-fidelity PCR, and the third exon of the HLA-E gene and the coding region of the HLA-G gene were sequenced. The allele frequency of HLA-E*01:03 in patients with PSS was significantly higher than that in the control group (P=0.017, corrected P=0.034, OR =1.66). The genotype frequencies of HLA-E*01:01/01:03 and HLA-E*01:03/01:03 in the PSS group were significantly higher than that in the control group (P=0.027, OR =2.62; P=0.011, OR =3.05; respectively). There were no significant differences in the frequency of HLA-G alleles and genotypes between the two groups (all P>0.05). The haplotype frequency of HLA-E*01:03-G*01:01 in the PSS group was significantly higher than that in the control group (P=0.019, OR =1.63), although this association did not survive the Bonferroni correction (corrected P=0.13). This study proved for the first time that HLA-E*01:03 and HLA-E*01:03-G*01:01 might be risk factors for PSS.

HLA-G and vertical mother-to-child transmission of human papillomavirus infection

Role of host factors in transmission of human papillomavirus (HPV)-infection from mother to her offspring is not known. Our aim was to study whether human leukocyte antigen (HLA)-G allele concordance among the mother–child pairs could facilitate vertical transmission of HPV, because HLA-G may contribute to immune tolerance in pregnancy. Altogether, 310 mother-child pairs were included from the Finnish Family HPV study. Overall, nine different HLA-G alleles were identified. The HLA-G genotype concordance of G∗01:01:01/01:04:01 increased the risk of high risk (HR)-HPV genotype positivity in cord blood and infant’s oral mucosa. The mother-child concordance of G∗01:01:02/01:01:02 increased the risk of oral HPV positivity with HR-HPV genotypes both in the mother and offspring; OR 2.45 (95%CI 1.24–4.85). Discordant HLA-G allele for G∗01:04:01 and for G∗01:06 was significantly associated with infant’s oral low risk (LR)-HPV at birth, OR 3.07 (95%CI 1.01–9.36) and OR 5.19 (95%CI 1.22–22.03), respectively. HLA-G had no association with HPV genotype-specific concordance between the mother and child at birth nor influence on perinatal HPV status of the child. Taken together, our results show that HLA-G molecules have a role in predicting the newborn’s likelihood for oral HPV infection at birth.

The Influence of Cytomegalovirus on Expression of HLA-G and its Ligand KIR2DL4 by Human Peripheral Blood Leucocyte Subsets.

HLA-G is a non-classical class I HLA antigen, normally expressed in high levels only on extravillous cytotrophoblast. It has immunosuppressive properties in pregnancy and has also been found to be upregulated on leucocytes in viral infection. In this study, proportions of all leucocyte subsets expressing HLA-G were found to be low in healthy subjects positive or negative for cytomegalovirus (CMV). Significantly greater proportions of CD4+ CD69+ and CD56+ T cells expressed HLA-G compared to other T cells. However, following stimulation with CMV antigens or intact CMV, proportions of CD4+, CD8+, CD69+ and CD56+ T cells, and also B cells expressing HLA-G, were significantly increased in CMV+ subjects. Despite some subjects having alleles of HLA-G associated with high levels of expression, no relationship was found between HLA-G genotype and expression levels. Purified B cells from CMV+ subjects stimulated in mixed culture with CMV antigens showed significantly increased HLA-G mRNA expression by real-time polymerase chain reaction. Serum levels of soluble HLA-G were similar in CMV- and CMV+ subjects but levels in culture supernatants were significantly higher in cells from CMV+ than from CMV- subjects stimulated with CMV antigens. The HLA-G ligand KIR2DL4 was mainly expressed on NK cells and CD56+ T cells with no differences between CMV+ and CMV- subjects. Following stimulation with IL-2, an increase in the proportion of CD56+ T cells positive for KIR2DL4 was found, together with a significant decrease in CD56dimCD16+ NK cells. The results show that CMV influences HLA-G expression in healthy subjects and may contribute to viral immune evasion.

Associations between fetal HLA-G genotype and birth weight and placental weight in a large cohort of pregnant women – Possible implications for HLA diversity

Birth weight and placental weight are crucial parameters for the survival of fetuses and newborns in mammals. High variation in the MHC is important for an effective adaptive immune response. The maternal immune system must be controlled in relation to the semi-allogenic fetus. The immunoregulatory HLA/MHC class Ib gene, HLA-G, is strongly expressed on extravillous trophoblast cells. We investigated birth weight and placental weight of the newborns in mothers heterozygous for an HLA-G 14bp insertion (Ins)/deletion (Del) gene polymorphism. Separate analyses for pregnancies without preeclampsia (n=185), pregnancies complicated by preeclampsia (n=101), and both groups combined, were performed. Interestingly, we observed the highest mean birth weight and placental weight in homozygous 14bp Del/Del newborns, and the lowest in 14bp Ins/Ins newborns (P=0.008 and P=0.009). The 14bp Del/Del genotype is also associated with high expression of HLA-G on the trophoblast membrane. In theory, fetuses and newborns with intermediate weights and sizes would be an optimal compromise for both the fetus/father and the mother compared with very high and low weights. If such fetuses/newborns more often are heterozygous at the HLA-G gene locus, then newborns with two distinct HLA haplotypes are favored, leading to a higher degree of HLA diversity. The results of the study may indicate that a compromise between an intermediate birth weight and placental weight, induction of maternal tolerance by a fetal-derived non-polymorphic HLA class Ib molecule, and favoring of HLA heterozygous offspring, have evolved in humans.

Correlation between maternal soluble HLA-G at midterm and term with umbilical cord soluble HLA-G and their association to maternal and fetal HLA-G genotypes

Correlation between maternal soluble HLA-G at midterm and term with umbilical cord soluble HLA-G and their association to maternal and fetal HLA-G genotypes

Correlation between maternal soluble HLA-G at midterm and term with umbilical cord soluble HLA-G and their association to maternal and fetal HLA-G genotypes

The immunotolerant HLA-G could generate seven isoforms including HLA-G1–-G7. The suppressive function of either HLA-G1 or HLA-G5 isoform to NK cell cytolysis has been well established. Whether HLA-G1 and HLA-G5 isoform have an additive effect on the cytolysis of NK cells remain to be explored. In this study, effects of expression of HLA-G1 and HLA-G5 isoforms and their combination on NK cytolysis was investigated. NK cell cytolysis was analyzed by detecting the NK cell surface CD107a expression. In this study, data showed that the inhibition capacity is dependent on the level of both HLA-G1 and HLA-G5 expression, but the HLA-G5 isoform has a more potent inhibition effect on the NK cytolysis (p < 0.01). Furthermore, HLA-G1 and HLA-G5 have an additive effect on the suppression of NK cell cytolysis. Our study provided further understanding for the roles of HLA-G1 and HLA-G5 isoform expression in target cells immune escaping from NK cells.

Association of 14-bp insertion/deletion polymorphism of HLA-G gene with idiopathic recurrent miscarriages in infertility center patients in Yazd, Iran

HLA-G is supposed to play a pivotal role in tolerance of the semi-allogeneic graft in pregnancy by inhibiting the cytotoxic functions of T and NK cells. A 14-bp insertion and/or deletion polymorphism in exon-8 has a possible role in HLA-G expression. The present study analyzed the 14-bp insertion/deletion polymorphism in normal pregnancy and recurrent miscarriage patients in order to discover a possible correlation between the 14-bp polymorphism and recurrent miscarriage (RM). In this study, genomic DNA from 200 RM patients and 200 normal fertile control individuals using the routine salting out method were isolated. Exon-8 of HLA-G gene of the two groups were amplified using polymerase chain reaction and analyzed by electrophoresis on 10% non-denaturing polyacrylamide gel electrophoresis containing ethidium bromide and visualized under ultraviolet light. HLA-G allele frequencies and genotypes in RM women and the fertile control group were compared using a Chi-square test. The results showed that there was a difference in allelic frequencies of 14-bp insertion polymorphism between fertile controls and RM patients; the frequency of +14 bp/−14 bp heterozygotes was significantly higher in RM patients as compared with fertile controls. Furthermore, the frequency of +14-bp insertion allele was significantly higher in those with RM as compared with normal fertile controls. From the findings here, it was concluded that a 14-bp insertion/deletion polymorphism in exon 8 could play a possible role in recurrent miscarriages. These results might ultimately be of significance for clinicians and those involved in understanding infertility and RM.

Human leukocyte antigen (HLA)-G during pregnancy part II: Associations between maternal and fetal HLA-G genotypes and soluble HLA-G

Human leukocyte antigen (HLA)-G is a class Ib molecule with restricted tissue distribution expressed on the extra-villous trophoblast and seems to have immunomodulatory functions during pregnancy. Studies have linked HLA-G polymorphisms to pregnancy complications such as preeclampsia and recurrent miscarriage. Levels of soluble HLA-G (sHLA-G) in blood plasma from non-pregnant donors seem to be associated with these polymorphisms. In the current study, we have genotyped 246 mothers and their offspring for HLA-G polymorphisms in the 3′-untranslated region (3′UTR) and measured sHLA-G in maternal blood plasma samples from gestational week 20 and at term, as well as in fetal umbilical cord blood samples. This is the first large study simultaneously performing HLA-G genotyping of mother and offspring and measuring sHLA-G in both maternal and umbilical cord blood. The results showed that increasing numbers of 14bp ins (rs66554220) alleles in the mother–child genotype combinations were associated with higher maternal sHLA-G levels at term when restricting the analysis to 14bp ins/del heterozygous mothers (p=0.015). Furthermore, increasing numbers of 14InsG haplotypes (14bp ins/del and +3142C/G (rs1063320) polymorphism) in mother–child genotype combinations were associated with higher levels of sHLA-G at term in heterozygous 14DelC/14InsG mothers (p=0.005). In conclusion, the results indicate that there is an association between combined feto-maternal HLA-G genotypes and sHLA-G levels in maternal blood plasma.

Human Leukocyte Antigen-G Within the Male Reproductive System: Implications for Reproduction.

In sexual reproduction in humans, a man has a clear interest in ensuring that the immune system of his female partner accepts the semi-allogenic fetus. Increasing attention has been given to soluble immunomodulatory molecules in the seminal fluid as one mechanism of ensuring this, possibly by "priming" the woman's immune system before conception and at conception. Recent studies have demonstrated the presence of the immunoregulatory and tolerance-inducible human leukocyte antigen (HLA)-G in the male reproductive organs. The expression of HLA-G in the blastocyst and by extravillous trophoblast cells in the placenta during pregnancy has been well described. Highly variable amounts of soluble HLA-G (sHLA-G) in seminal plasma from different men have been reported, and the concentration of sHLA-G is associated with HLA-G genotype. A first pilot study indicates that the level of sHLA-G in seminal plasma may even be associated with the chance of pregnancy in couples, where the male partner has reduced semen quality. More studies are needed to verify these preliminary findings.

Human Leukocyte Antigen-G Polymorphisms Influence Clinical Outcome in Diffuse Large B-Cell Lymphoma

There is growing evidence that genetic variations in the human leukocyte antigen (HLA) genes play a role in the etiology and clinical course of NHL. HLA-G belongs to the non-classical class I major histocompatibility complex-1 (MHC-I) polymorphic molecules and due to its suppression of immune response it is able to facilitate tumor escape from immunosurveillance. Several polymorphisms in the HLA-G gene have been reported to significantly affect its expression. Therefore, we investigated whether functionally relevant HLA-G polymorphisms, HLA-G-725C/G/T and HLA-G 14-bp, have any influence on the susceptibility to, and clinical course of, diffuse large B-cell lymphoma (DLBCL). The polymorphisms were genotyped in 207 previously untreated patients with DLBCL and 150 unrelated controls. A significant difference in genotype distribution of HLA-G polymorphic genotypes between the patients and controls was found. The frequencies of the HLA-G-725GG or the HLA-G-725GC genotype were lower (OR [odds ratio]= 0.47, P= 0.004), and those of the HLA-G ins/ins genotype were higher (OR= 2.08, P= 0.004) in the patients compared to controls. In univariate logistic regression analysis, neither HLA-G -725C/G/T nor HLA-G 14-bp influenced the probability of achieving a remission. There was no influence of HLA-G polymorphisms on the probability of progression-free survival (PFS). However, the patients carrying the HLA-G-725CC genotype presented a higher probability of 5-year overall survival (OS) than subjects with other genotype combinations of HLA-G-725C/G/T (38.2% vs 21.7%, P=0.003, log-rank test). The estimated 5-year OS among the homozygotes HLA-G del/del was 18.9% compared to the 35.3% in the subjects carrying the HLA-G del/ins or the 46.1% in those with the HLA-G ins/ins genotype (P=0.009, log-rank test). In a multivariate Cox analysis adjusted for IPI factors, we found that both the HLA-G -725C/G/T polymorphism (P= 0.01) and the IPI (P< 0.0001) retained their independent prognostic impact on OS The influence of the particular genotypes of the HLA-G -725C/G/T and the HLA-G 14-bp polymorphism on OS allow us to single out two HLA-G genotype-based risk groups. The low risk (LR) group included the patients carrying the HLA-G -725CC genotype and the HLA-G del/ins or the HLA-G ins/ins genotype. In contrast, the high risk (HR) group comprised those patients with other HLA-G genotype combinations. It is worth noting that the estimated 5-year OS rate of patients with LR genotypes was 42.7% in comparison to the 19.3% (P= 0.001, log-rank test) in patients with HR genotypes. An additional multivariate analysis, including HLA-G genotype-based risk groups and the IPI, revealed that both the intermediate high/high IPI risk group (P< 0.0001) and the HR genotype group (P= 0.004) independently increased the risk of death.This is the first study indicating an important role for HLA-G polymorphisms in the clinical course of DLBCL. The potential influence of HLA-G polymorphisms on the susceptibility to DLBCL deserves further study. It would seem that the inherited ability of the host to suppress anti-tumor immune response and then facilitate tumor escape from immunosurveillance might contribute to the pathogenesis and prognosis of B-cell malignancies. DisclosuresRobak:MorphoSys AG: Research Funding.

Soluble human leukocyte antigen-G in seminal plasma is associated with HLA-G genotype: possible implications for fertility success.

We have previously shown that human seminal plasma contains immunomodulatory soluble HLA-G (sHLA-G). We investigated whether sHLA-G levels in seminal plasma are associated with a specific 14 base pair (bp) insertion/deletion (ins/del) polymorphism in the 3'-untranslated region of the HLA-G gene and/or with the outcome of assisted reproduction treatments (ART) in couples attending a fertility clinic. In a total of 54 unselected couples, sHLA-G levels were measured in seminal plasma samples and blood samples, HLA-G genotyping was performed, and clinical data were collected. The concentration of sHLA-G in seminal plasma samples was significantly associated with the HLA-G 14 bp ins/del genotype of the men; the del14 bp/del14 bp genotype showed the highest level of sHLA-G, and the ins14 bp/ins14 bp genotype showed the lowest level (P = 0.003). We observed a trend for higher seminal plasma levels of sHLA-G/total protein and total sHLA-G in cases with reduced semen quality, where the female partner became pregnant after ART, compared with those couples in which no pregnancy was achieved. These first results are in accordance with a possible role of seminal sHLA-G as an immunomodulatory factor in the female reproductive tract before and at the time of conception.