HLA Class Ia Research Articles

HLA-E-restricted SARS-CoV-2-specific T cells from convalescent COVID-19 patients suppress virus replication despite HLA class Ia down-regulation.

Pathogen-specific CD8+ T cell responses restricted by the nonpolymorphic nonclassical class Ib molecule human leukocyte antigen E (HLA-E) are rarely reported in viral infections. The natural HLA-E ligand is a signal peptide derived from classical class Ia HLA molecules that interact with the NKG2/CD94 receptors to regulate natural killer cell functions, but pathogen-derived peptides can also be presented by HLA-E. Here, we describe five peptides from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that elicited HLA-E-restricted CD8+ T cell responses in convalescent patients with coronavirus disease 2019. These T cell responses were identified in the blood at frequencies similar to those reported for classical HLA-Ia-restricted anti-SARS-CoV-2 CD8+ T cells. HLA-E peptide-specific CD8+ T cell clones, which expressed diverse T cell receptors, suppressed SARS-CoV-2 replication in Calu-3 human lung epithelial cells. SARS-CoV-2 infection markedly down-regulated classical HLA class I expression in Calu-3 cells and primary reconstituted human airway epithelial cells, whereas HLA-E expression was not affected, enabling T cell recognition. Thus, HLA-E-restricted T cells could contribute to the control of SARS-CoV-2 infection alongside classical T cells.

Distinctive phenotype for HLA-E- versus HLA-A2-restricted memory CD8 αβT cells in the course of HCMV infection discloses features shared with NKG2C+CD57+NK and δ2-γδT cell subsets.

The human cytomegalovirus (HCMV) triggers both innate and adaptive immune responses, including protective CD8+ αβT cells (CD8T) that contributes to the control of the infection. In addition to CD8T restricted by classical HLA class Ia molecules, HCMV also triggers CD8T recognizing peptides from the HCMV UL40 leader peptide and restricted by HLA-E molecules (HLA-EUL40 CD8T). This study investigated the frequency, phenotype and functions of HLA-EUL40 CD8T in comparison to the immunodominant HLA-A2pp65 CD8T upon acute (primary or secondary infection) or chronic infection in kidney transplant recipients (KTR) and in seropositive (HCMV+) healthy volunteer (HV) hosts. The frequency of hosts with detected HLA-EUL40 CD8T was similar after a primary infection (24%) and during viral latency in HCMV+ HV (26%) and equal to the frequency of HLA-A2pp65 CD8T cells in both conditions (29%). Both CD8T subsets vary from 0.1% to >30% of total circulating CD8T according to the host. Both HLA-EUL40 and HLA-A2pp65 CD8T display a phenotype specific of CD8+ TEMRA (CD45RA+/CCR7-) but HLA-EUL40 CD8T express distinctive level for CD3, CD8 and CD45RA. Tim3, Lag-3, 4-1BB, and to a lesser extend 2B4 are hallmarks for T cell priming post-primary infection while KLRG1 and Tigit are markers for restimulated and long lived HCMV-specific CD8T responses. These cell markers are equally expressed on HLA-EUL40 and HLA-A2pp65 CD8T. In contrast, CD56 and PD-1 are cell markers discriminating memory HLA-E- from HLA-A2-restricted CD8T. Long lived HLA-EUL40 display higher proliferation rate compared to HLA-A2pp65 CD8T consistent with elevated CD57 expression. Finally, a comparative immunoprofiling indicated that HLA-EUL40 CD8T, divergent from HLA-A2pp65 CD8T, share the expression of CD56, CD57, NKG2C, CD158 and the lack of PD-1 with NKG2C+CD57+ NK and δ2-γδT cells induced in response to HCMV and thus defines a common immunopattern for these subsets.

Mouse and human antibodies bind HLA-E-leader peptide complexes and enhance NK cell cytotoxicity

The non-classical class Ib molecule human leukocyte antigen E (HLA-E) has limited polymorphism and can bind HLA class Ia leader peptides (VL9). HLA-E-VL9 complexes interact with the natural killer (NK) cell receptors NKG2A-C/CD94 and regulate NK cell-mediated cytotoxicity. Here we report the isolation of 3H4, a murine HLA-E-VL9-specific IgM antibody that enhances killing of HLA-E-VL9-expressing cells by an NKG2A+ NK cell line. Structural analysis reveal that 3H4 acts by preventing CD94/NKG2A docking on HLA-E-VL9. Upon in vitro maturation, an affinity-optimized IgG form of 3H4 showes enhanced NK killing of HLA-E-VL9-expressing cells. HLA-E-VL9-specific IgM antibodies similar in function to 3H4 are also isolated from naïve B cells of cytomegalovirus (CMV)-negative, healthy humans. Thus, HLA-E-VL9-targeting mouse and human antibodies isolated from the naïve B cell antibody pool have the capacity to enhance NK cell cytotoxicity.

Structure-guided stabilization of pathogen-derived peptide-HLA-E complexes using non-natural amino acids conserves native TCR recognition.

The nonpolymorphic class Ib molecule, HLA‐E, primarily presents peptides from HLA class Ia leader peptides, providing an inhibitory signal to NK cells via CD94/NKG2 interactions.Although peptides of pathogenic origin can also be presented by HLA‐E to T cells, the molecular basis underpinning their role in antigen surveillance is largely unknown. Here, we solved a co‐complex crystal structure of a TCR with an HLA‐E presented peptide (pHLA‐E) from bacterial (Mycobacterium tuberculosis) origin, and the first TCR‐pHLA‐E complex with a noncanonically presented peptide from viral (HIV) origin. The structures provided a molecular foundation to develop a novel method to introduce cysteine traps using non‐natural amino acid chemistry that stabilized pHLA‐E complexes while maintaining native interface contacts between the TCRs and different pHLA‐E complexes. These pHLA‐E monomers could be used to isolate pHLA‐E‐specific T cells, with obvious utility for studying pHLA‐E restricted T cells, and for the identification of putative therapeutic TCRs.

HLA-E diversity unfolded: Identification and characterization of 170 novel HLA-E alleles.

HLA‐E is a member of the nonclassical HLA class Ib genes. Even though it is structurally highly similar to the classical HLA class Ia genes, it is less diverse and only 45 alleles and 12 proteins were known in December 2019 (IPD‐IMGT/HLA, release 3.38.0). Since 2017, we have genotyped over 3 million voluntary stem cell donors for HLA‐E by sequencing the most relevant allele‐determining bases of exons 2 and 3. As expected, most donors harbor the two predominant alleles HLA‐E*01:01 and/or HLA‐E*01:03. However, in 1666 (0.05%) of our samples we detected 345 distinct novel HLA‐E sequences. The most frequent one was identified in 162 samples and has by now been named HLA‐E*01:114. To characterize these novel alleles in full‐length, we used both short‐read Illumina and long‐read PacBio sequencing to obtain fully phased and highly accurate sequences. This resulted in 234 submissions to IPD‐IMGT/HLA comprising 170 novel HLA‐E alleles, which encode for 93 novel HLA‐E proteins, as well as 64 confirmations or sequence extensions. Consequently, the number of HLA‐E alleles in the database (release 3.42.0) has now increased to 256 HLA‐E alleles and 110 HLA‐E proteins.

The role of donor-unrestricted T-cells, innate lymphoid cells, and NK cells in anti-mycobacterial immunity.

Vaccination strategies against mycobacteria, focusing mostly on classical T‐ and B‐cells, have shown limited success, encouraging the addition of alternative targets. Classically restricted T‐cells recognize antigens presented via highly polymorphic HLA class Ia and class II molecules, while donor‐unrestricted T‐cells (DURTs), with few exceptions, recognize ligands via genetically conserved antigen presentation molecules. Consequently, DURTs can respond to the same ligands across diverse human populations. DURTs can be activated either through cognate TCR ligation or via bystander cytokine signaling. TCR‐driven antigen‐specific activation of DURTs occurs upon antigen presentation via non‐polymorphic molecules such as HLA‐E, CD1, MR1, and butyrophilin, leading to the activation of HLA‐E–restricted T‐cells, CD1‐restricted T‐cells, mucosal‐associated invariant T‐cells (MAITs), and TCRγδ T‐cells, respectively. NK cells and innate lymphoid cells (ILCs), which lack rearranged TCRs, are activated through other receptor‐triggering pathways, or can be engaged through bystander cytokines, produced, for example, by activated antigen‐specific T‐cells or phagocytes. NK cells can also develop trained immune memory and thus could represent cells of interest to mobilize by novel vaccines. In this review, we summarize the latest findings regarding the contributions of DURTs, NK cells, and ILCs in anti–M tuberculosis, M leprae, and non‐tuberculous mycobacterial immunity and explore possible ways in which they could be harnessed through vaccines and immunotherapies to improve protection against Mtb.

Investigations of sequencing data and sample type on HLA class Ia typing with different computational tools.

Human leukocyte antigen (HLA) can encode the human major histocompatibility complex (MHC) proteins and play a key role in adaptive and innate immunity. Emerging clinical evidences suggest that the presentation of tumor neoantigens and neoantigen-specific T cell response associated with MHC class I molecules are of key importance to activate the adaptive immune systemin cancer immunotherapy. Therefore, accurate HLA typing is very essential for the clinical application of immunotherapy. In this study, we conducted performance evaluations of 4 widely used HLA typing tools (OptiType, Phlat, Polysolver and seq2hla) for predicting HLA class Ia genes from WES and RNA-seq data of 28 cancer patients. HLA genotyping data using PCR-SBT method was firstly obtained as the golden standard and was subsequently compared with HLA typing data by using NGS techniques. For both WES data and RNA-seq data, OptiType showed the highest accuracy for HLA-Ia typing than the other 3 programs at 2-digit and 4-digit resolution. Additionally, HLA typing accuracy from WES data was higher than from RNA-seq data (99.11% for WES data versus 96.42% for RNA-seq data). The accuracy of HLA-Ia typing by OptiType can reach 100% with the average depth of HLA gene regions >20x. Besides, the accuracy of 2-digit and 4-digit HLA-Ia typing based on control samples was higher than tumor tissues. In conclusion, OptiType by using WES data from control samples with the high average depth (>20x) of HLA gene regions can present a probably superior performance for HLA-Ia typing, enabling its application in cancer immunotherapy.

Between Innate and Adaptive Immune Responses: NKG2A, NKG2C, and CD8⁺ T Cell Recognition of HLA-E Restricted Self-Peptides Acquired in the Absence of HLA-Ia.

On healthy cells the non-classical HLA class Ib molecule HLA-E displays the cognate ligand for the NK cell receptor NKG2A/CD94 when bound to HLA class I signal peptide sequences. In a pathogenic situation when HLA class I is absent, HLA-E is bound to a diverse set of peptides and enables the stimulatory NKG2C/CD94 receptor to bind. The activation of CD8+ T cells by certain p:HLA-E complexes illustrates the dual role of this low polymorphic HLA molecule in innate and adaptive immunity. Recent studies revealed a shift in the HLA-E peptide repertoire in cells with defects in the peptide loading complex machinery. We recently showed that HLA-E presents a highly diverse set of peptides in the absence of HLA class Ia and revealed a non-protective feature against NK cell cytotoxicity mediated by these peptides. In the present study we have evaluated the molecular basis for the impaired NK cell inhibition by these peptides and determined the cell surface stability of individual p:HLA-E complexes and their binding efficiency to soluble NKG2A/CD94 or NKG2C/CD94 receptors. Additionally, we analyzed the recognition of these p:HLA-E epitopes by CD8+ T cells. We show that non-canonical peptides provide stable cell surface expression of HLA-E, and these p:HLA-E complexes still bind to NKG2/CD94 receptors in a peptide-restricted fashion. Furthermore, individual p:HLA-E complexes elicit activation of CD8+ T cells with an effector memory phenotype. These novel HLA-E epitopes provide new implications for therapies targeting cells with abnormal HLA class I expression.

HLA class Ia and Ib molecules and FOXP3+ TILs in relation to the prognosis of malignant melanoma patients

HLA class Ia (HLA-ABC) and HLA class Ib (HLA-E, -F and -G) molecules and FOXP3+ tumor-infiltrating lymphocytes (TILs) are often reported as relevant factors of tumor immune regulation. We investigated their expression as prognostic factors in 200 patients with primary cutaneous melanoma (PCM). In our cohort, patients with tumors showing upregulation of HLA-ABC molecules had significantly thicker tumors (32% vs 7%, P<0.001), frequent ulceration (20% vs 6%, P=0.007) and frequent nodular melanomas (20% vs 4%, P=0.001). Additionally, high expression of HLA-G in the tumor was a sign of bad prognosis for the patients, being associated with thick tumors (30% vs 12%, P=0.017), ulceration (24% vs 5%, P<0.001) and positive sentinel node (13% vs 6%, P=0.015). HLA-E, HLA-F and FOXP3+ TILs were not indicative of the prognosis in PCM. High HLA-ABC and HLA-G were associated with tumor aggressiveness and could be relevant predictive markers for effective immunotherapy of melanoma tumors.

HLA class Ib in pregnancy and pregnancy-related disorders.

The HLA class Ib genes, HLA-E, HLA-F, and HLA-G, were discovered long after the classical HLA class Ia genes. The elucidation of their functions had a modest beginning. However, their basic functions and involvement in pathophysiology and a range of diseases are now emerging. Although results from a range of studies support the functional roles for the HLA class Ib molecules in adult life, especially HLA-G and HLA-F have most intensively been, and were also primarily, studied in relation to reproduction and pregnancy. The expression of HLA class Ib proteins at the feto-maternal interface in the placenta seems to be important for the maternal acceptance of the semi-allogenic fetus. In contrast to the functions of HLA class Ia, HLA-G possesses immune-modulatory and tolerogenic functions. Here, we review an accumulating amount of data describing the functions of HLA class Ib molecules in relation to fertility, reproduction, and pregnancy, and a possible role for these molecules in certain pregnancy complications, such as implantation failure, recurrent spontaneous abortions, and pre-eclampsia. The results from different kinds of studies point toward a role for HLA class Ib, especially HLA-G, throughout the reproductive cycle from conception to the birth weight of the child.

P 56 The role of anti- and pro-inflammatory cytokines on the expression of the tolerogenic HLA class Ib molecules in relation to pregnancy and preeclampsia

Introduction Preeclampsia (PE) is a multi-systemic pregnancy disorder and an important cause of fetal and maternal morbidity and mortality worldwide. Although the exact etiology behind PE is unclear, one widely accepted hypothesis propose that a maladapted immune response in the mother cause inadequate trophoblast invasion and remodeling of the spiral arteries, leading to hypoxia and ischemia. Whereas uncomplicated pregnancies is characterized by immunological tolerance towards the fetal cells established through immunological mediators such as HLA-C and the non-classical HLA-Ib molecules and regulatory immune cells, PE is characterized by the presence of pro-inflammatory leukocytes and cytokines. The direct consequence of the presence of the pro-inflammatory cytokines in the local environment and on the fetal cells is less studied. Objectives The aim is to characterize the effect of the anti- and pro-inflammatory cytokines on the expression of HLA class I molecules on the trophoblast cell line JEG-3 and primary placenta tissue. Materials and methods JEG-3 cells are incubated in the presence of various concentrations of anti- and pro-inflammatory cytokines for up to 72 h. HLA-C, -E and -G surface expression is characterized by flow cytometry, mRNA levels of HLA class Ia and Ib is quantified by droplet digital PCR, and expression of the different isoforms of HLA-G (HLA-G1-7) is analyzed by fragment analysis. Results Our preliminary data suggests an upregulation of the HLA-Ib molecules upon culture with IFN-γ, whereas IL-12 seems to slightly downregulate the expression of HLA-G. The effect on mRNA level and on expression of different isoforms of HLA-G is currently being investigated. Conclusion Expression of HLA-I molecules seems to be affected by the presence of specific cytokines in the local environment. Whether this act of balancing is also seen in primary placenta tissue from healthy pregnancies or cases of PE will be determined in nearest future.

Feasibility study of multiple HLA-class IA restricted peptide vaccines (KRM-19) for metastatic triple negative breast cancer (TNBC).

164 Background: Our previous phase II clinical trial has indicated that the therapeutic selected personalized peptide vaccines (PPV) were effective for boosting anticancer immunity and the immune response after PPV was associated with the clinical outcome as a prognostic factor for metastatic breast cancer (mBC). Based on the data from the PPV studies, we have conducted an early phase II study to evaluate the safety and the efficacy of a new regimen using multiple peptide vaccines (KRM-19) for pts with metastatic TNBC. Methods: KRM-19 consisted of 19 mixed peptides which were chosen from the previously reported 31 PPVs according to their anti-tumor immunologic effect and safety profile for mBC pts. All patients had histologically confirmed measurable ER-PgR-Her2- mBC and their human leukocyte antigen (HLA)-A molecules should be each of -A2, A3, A11, A24, A26, A31, or A33. KRM-19 (19mg/ml) was administrated subcutaneously in order with schedule of every week for a total of 6 doses. The concurrent conventional chemo- and/or endocrine therapy was not permitted for the combination, but was available for post-study treatment. Measurement of peptide-specific cytotoxic T lymphocyte (CTL) and IgG responses were conducted before and after vaccination. Levels of IgG reactive to each of the 19 peptides in the pre- and post-vaccination plasma were measured using the LUMINEX system at every 6 vaccinations. Peptide-specific CTL responses were examined by INF-ɤ ELISPOT. Clinical response was evaluated by RECIST criteria. Results: 10 patients with refractory metastatic TNBC received all 6 vaccines and 10/10 patients experienced Grade 1-2 skin reaction at injection site, 5/10 pts had Grade 2-3 liver function disorder, 3/10 and 1/10 pts had Grade 2 bone marrow suppression and nausea, respectively. The clinical responses were assessed in 8 pts included 1 PR case, 4 SD cases, and 3 PD cases. The evaluation of other clinical and immunologic data is underway. Conclusions: Subcutaneous KRM-19 vaccine administration was safe and resulted in a 12.5% objective response and 62.5% clinical benefit rate in TNBC pts, warranting further larger scale study. Clinical trial information: UMIN000014616.

Interaction of the LILRB1 inhibitory receptor with HLA class Ia dimers.

Leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) has been reported to interact with a wide spectrum of HLA class I (HLA-I) molecules, albeit with different affinities determined by allelic polymorphisms and conformational features. HLA-G dimerization and the presence of intracellular Cys residues in HLA-B7 have been shown to be critical for their recognition by LILRB1. We hypothesized that dimerization of classical HLA class Ia molecules, previously detected in exosomes, might enhance their interaction with LILRB1. A soluble LILRB1-Fc fusion protein and a sensitive cellular reporter system expressing a LILRB1-ζ chimera were employed to assess receptor interaction with different HLA class Ia molecules transfected in the human lymphoblastoid 721.221 cell line. Under these conditions, intracellular Cys residues and HLA-I dimerization appeared associated with increased LILRB1 recognition. On the other hand, a marginal interaction of LILRB1 with primary monocytic cells, irrespective of their high HLA-I expression, was enhanced by type I interferon (IFN). This effect appeared disproportionate to the cytokine-induced increase of surface HLA-I expression and was accompanied by detection of HLA class Ia dimers. Altogether, the results support that a regulated assembly of these noncanonical HLA-I conformers during the immune response may enhance the avidity of their interaction with LILRB1.

HLA Analysis of CD15+ Granulocytes of Leukemic Patients and Assessment of its Implication in Leukemia Immunotherapy

It is of common knowledge that most leukemic patients succumb to infectious complications beside dysfunction in proliferation/differentiation of hematopoietic cells . Recently, it has been shown by several groups that there is a locus specific HLA class I downregulation in the leukemic cells. However, the HLA status of the phenotypically/morphologically normal granulocytes which can cope up with the infectious complications are not known. Therefore it may be worthwhile to study the HLA status in these cell types. We, therefore, investigated the status of HLA-ABC and HLA-DR in the CD15 + granulocytes and observed a higher expression of HLA-DR in several leukemic samples in comparison to normal volunteers (NV). Our data also suggest that only CD15 + granulocytes of myeloid leukemia, a clonal stem cell disorder, have a tendency of decreased HLA class Ia antigen expression. Moreover CD15 + granulocytes of NV showed an enhanced HLA-DR expression in presence of leukemic cells. Interestingly, CD15 + granulocytes collected from normal volunteers were observed to have phagocytic oxidative burst activity towards HLA class Ia downregulated primary leukemic cells. We therefore suggest that neutrophil transplantation may be used for the treatment of leukemia.

Innovative Strategies to Identify M. tuberculosis Antigens and Epitopes Using Genome-Wide Analyses

In view of the fact that only a small part of the Mtb expressome has been explored for identification of antigens capable of activating human T-cell responses, which is critically required for the design of better TB vaccination strategies, more emphasis should be placed on innovative ways to discover new Mtb antigens and explore their function at the several stages of infection. Better protective antigens for TB-vaccines are urgently needed, also in view of the disappointing results of the MVA85 vaccine, which failed to induce additional protection in BCG-vaccinated infants (1). Moreover, immune responses to relevant antigens may be useful to identify TB-specific biomarker signatures. Here, we describe the potency of novel tools and strategies to reveal such Mtb antigens. Using proteins specific for different Mtb infection phases, many new antigens of the latency-associated Mtb DosR-regulon as well as resuscitation promoting factor proteins, associated with resuscitating TB, were discovered that were recognized by CD4+ and CD8+ T-cells. Furthermore, by employing MHC binding algorithms and bioinformatics combined with high-throughput human T-cell screens and tetramers, HLA-class Ia restricted polyfunctional CD8+ T-cells were identified in TB patients. Comparable methods, led to the identification of HLA-E-restricted Mtb epitopes recognized by CD8+ T-cells. A genome-wide unbiased antigen discovery approach was applied to analyze the in vivo Mtb gene expression profiles in the lungs of mice, resulting in the identification of IVE-TB antigens, which are expressed during infection in the lung, the main target organ of Mtb. IVE-TB antigens induce strong T-cell responses in long-term latently Mtb infected individuals, and represent an interesting new group of TB antigens for vaccination. In summary, new tools have helped expand our view on the Mtb antigenome involved in human cellular immunity and provided new candidates for TB vaccination.

Phase II study of personalized peptide vaccination for refractory bone and soft tissue sarcoma patients

Refractory bone and soft tissue sarcomas are challenging diseases to treat because of their robustness to chemotherapy. Although cancer vaccines have the potential to become an attractive treatment modality, their progress has been hampered by the presence of many subtypes of sarcomas and different human leukocyte antigen (HLA)‐types. We investigated whether personalized peptide vaccination (PPV) would be feasible for the vast majority of sarcoma patients. Twenty refractory bone and soft tissue sarcoma patients with nine different subtypes and 11 different HLA‐class IA phenotypes were enrolled in this study. A maximum of four HLA‐matched peptides showing higher peptide‐specific IgG responses in pre‐vaccination plasma were selected from 31 pooled peptide candidates applicable for the HLA‐A2, ‐A3, ‐A11, ‐A24, ‐A26, ‐A31, and ‐A33 types, and were subcutaneously administered weekly for 6 weeks and bi‐weekly thereafter. Measurement of peptide‐specific CTL and IgG responses along with other laboratory analyses were conducted before and after vaccination. No patients were excluded by either sarcoma subtypes or different HLA‐types. No severe adverse events associated with PPV were observed in any patients. Peptide‐specific immunological boosting was observed in the post‐vaccination samples from the majority of patients. Tumor reduction of the lung metastasis and a long stable disease was observed in each case, and the median overall survival time of the 20 cases was 9.6 months. Taken together, PPV could be feasible for the vast majority of refractory sarcoma patients because of the safety and higher rates of immunological responses regardless of the presence of different sarcoma subtypes and various HLA‐types.

Association of HLA Class IA Polymorphisms with BK Virus Nephropathy in Kidney Transplant Recipients

Background: The association of HLA class I locus A polymorphisms with BK Virus Nephropathy (BKVN) is unclear. Methods: Using OPTN/UNOS database as of Oct 2011, we selected first kidney only transplants during 2004-5. Recipients with primary graft failure or failure before discharge were excluded. Logistic regression was used to examine the risk of BKVN according to donor and recipient HLA class I locus A and donor/recipient (D/R) mismatch. Results were adjusted by recipient age, donor type, induction, maintenance drugs and PRA. Results: Of 28,306 transplants, 962(3.4%) developed BKVN within a median time of 352 days (p25-75: 189-608) and 442 graft failures. One year incidence was 2.1%. Risk factors for BKVN were: pediatric recipients (vs. adults), use of thymoglobulin (vs. no induction), 3 to 6 HLA mismatches (vs. zero mismatch and considering HLA A, B and DR), and use of Mycophenolate Mofetil (vs. no anti-proliferative drug). Odds ratio (OR) for BKVN associated with one and two HLA A mismatch was 1.58(1.30-1.92) and 1.86(1.53-2.27), respectively, compared to zero HLA A mismatch. Taking other risk factors into account, the adjusted OR for BKVN associated with HLA A polymorphisms are shown in the Table.Table: No Caption available.Conclusion: HLA-A mismatch was associated with 58 to 86% increase in risk of BKN. Mismatch involving A1, A25, and A33 was associated with increased risk of BKN, while HLA A2, A26, and A68 expression in both donor and recipient was associated with decreased risk of BKN. This association with HLA disparity may be related to the pathogenesis of BKVN, and is under investigation in our laboratories.

Association of HLA Class IA Polymorphisms with BK Virus Nephropathy in Kidney Transplant Recipients

Association of HLA Class IA Polymorphisms with BK Virus Nephropathy in Kidney Transplant Recipients

Immunological evaluation of personalized peptide vaccination for metastatic breast cancer patients with triple-negative types.

e13046 Background: To develop cancer vaccine, we investigated immune responses of the patients (pts) with metastatic breast cancer (MBC) with triple negative (TN) types to personalized peptide vaccine (PPV). Methods: Thirty-four pts including 8 TN-MBC were enrolled a phase II study of PPV. A maximum of four HLA-class IA (A2, A3s, A24, A26)-matched peptides showing higher antigen-specific IgG responses were administered. Levels of IgG reactive to each of the 31 peptides in the pre- and post-treatment plasma at every 6 times of vaccination were measured using LUMNEX system. Peptide-specific CTL responses were examined by INF-g ELISPOT. Results: All 34 pts had significant pre-existing humoral immunity, whereas only 13 of 31 patients, including 3 of 6 TN cases, showed pre-existing cellular immunity. Thirty-one of 34 pts, including 6 TN cases, achieved more than one cycle (6 times) of vaccination. The augmentation of the IgG responses specific to at least one of the vaccinated peptides was observed in 18 of 31 pts, including 3 of 6 TN cases. CTL responses were augmented in 16 of 31 pts, including 5 of 6 TN cases. IgG responses were boosted to greater levels with 12th vaccination in all 31 pts tested including 6 TN cases. Best clinical responses of 6 TN cases were 1 CR, 0 PR, 5 SD, and 0 PD, while those of the other 25 cases were 1 CR, 1 PR, 17 SD, and 6 PD, respectively. Conclusions: There were no significant differences between TN cases and the other cases of MBC with regard to immunological humoral and/or cellular responses to PPV.

Phase II study of personalized peptide vaccine for refractory breast cancer patients.

e13050 Background: To develop therapeutic cancer vaccine, we conducted a phase II study of personalized peptide vaccine (PPV) for refractory breast cancer patients. Methods: Thirty-four refractory breast cancer patients, including 8 triple negative (TN) cases, were enrolled to this study. A maximum of four HLA-class IA (A2, A3s, A24, A26)-matched peptides showing higher antigen-specific IgG responses were administered. Inflammatory markers, cytokines, and peptide-specific CTL and IgG responses were examined before and after vaccination to identify prognostic factors for overall survival (OS). Results: No vaccine-related severe adverse events were observed. Median numbers of preceding chemo- and/or hormone therapy regimens and median treatment duration from the recurrence to the vaccination were 2 regimens and 37 months, respectively. Three patients did not complete the 6th vaccination because of rapid disease progression. CTL or IgG boosting by PPV was observed in 16 or 18 of 31 patients at the time of 6th vaccination. IgG boosting was observed in all 24 patients tested at 12th vaccination. Median survival time of 31 patients receiving &gt; 6th vaccination after the vaccination was 474 days with 2 complete responses and 1 partial response. There were no significant differences between 8 TN cases and the other cases from points of immunological and clinical responses. Lymphocyte frequency (Hazard ratio of 0.906, p=0.019) well associated with OS by multivariate Cox proportional hazard regression analysis for pre-vaccination samples. Conclusions: Next steps of PPV for the refractory breast cancer patients were warranted because of the lower toxicity and favorite immune responses along with possible clinical benefits.