Combination of neutrophil to lymphocyte ratio, platelet to lymphocyte ratio with plasma D-dimer level to improve the diagnosis of deep venous thrombosis (DVT) following ankle fracture.

PURPOSE: To investigate the relationship between neutrophil to lymphocyte ratio (NLR)/platelet to lymphocyte ratio (PLR) with deep venous thrombosis (DVT) following ankle fracture and the diagnostic ability of combination model. METHOD: This retrospective study included patients with a diagnosis of ankle fracture who had undergone preoperative Duplex ultrasound (DUS) examination for detecting the possible deep venous thrombosis (DVT). The variables of interest, the calculated NLR and PLR and others (demographics, injury, lifestyles and comorbidities) were extracted from the medical records. Two independent multivariate logistics regression models were used to detect the relationship between NLR or PLR and DVT. If any, combination diagnostic model was constructed and its diagnostic ability was evaluated. RESULTS: There were 1103 patients included, and 92 (8.3%) were found to have preoperative DVT. The NLR and PLR, which had respective optimal cut-off point of 4 and 200, were significantly different between patients with and without DVT either in continuous or categorical variable. After adjustment for covariates, both NLR and PLR were identified as independent risk factors associated with DVT, with odd ratio of 2.16 and 2.84, respectively. The combination diagnostic model, including NLR, PLR and D-dimer, demonstrated to significantly improved the diagnostic performance than any one alone or combined (all P < 0.05), and the area under the curve was 0.729 (95% CI 0.701-0.755). CONCLUSION: We concluded the relatively low incidence rate of preoperative DVT after ankle fracture, and both NLR and PLR were independently associated with DVT. The combination diagnostic model can be considered as a useful auxiliary tool for identifying high-risk patients for DUS examination.

Drain vs. no-drain for acetabular fractures after treatment via a modified stoppa approach: A retrospective study.

Objective: The aim of this study was to compare the clinical efficacy of close suction drainage (CSD) and no-CSD after a modified Stoppa approach for the surgical fixation of acetabular fractures. Methods: This retrospective study included 49 consecutive acetabular fracture patients, who presented to a single level I trauma center for surgical fixation, using a modified Stoppa approach from January 2018 to January 2021. All surgeries were performed by a senior surgeon using the same approach, and the patients were divided into two groups based on whether CSD was used after the operation. Details of the patient demographics, fracture characteristics, intraoperative indicators, reduction quality, intra and postoperative blood transfusion, clinical outcomes, and incision-related complications were collected. Results: No significant differences were found in the demographics, fracture characteristics, intraoperative indicators, reduction quality, clinical outcomes, and incision-related complications between the two groups (P > 0.05). The use of CSD was associated with a significantly higher postoperative blood transfusion volume (P = 0.034) and postoperative blood transfusion rate (P = 0.027). In addition, there was a significant difference in postoperative temperatures, especially on postoperative Day 2 (no-CSD 36.97 ± 0.51°C vs. CSD 37.34 ± 0.69°C, P = 0.035), and higher visual analogue scale (VAS) scores, especially on postoperative Day 1 (no-CSD 3.00 ± 0.93 vs. CSD 4.14 ± 1.43, P = 0.002) and 3 (no-CSD 1.73 ± 0.94 vs. CSD 2.48 ± 1.08, P = 0.013). Conclusion: The results of this study suggest that routine use of CSD should not be recommended for patients with acetabular fractures after surgical fixation using a modified Stoppa approach.

Clinical effect of closed reduction minimally invasive fixation in intra-articular comminuted fractures of the femoral condyle.

Objective: To evaluate the advantages of double reverse traction closed reduction combined with minimally invasive fixation in treating femoral condylar comminuted fractures. Methods: We retrospectively enrolled a total of 24 patients with femoral condylar comminuted fractures (AO = 33C3) admitted to Third Hospital of Hebei Medical University from March 2018 to February 2020. The patients were divided into two groups: experimental group (double reverse traction, n = 12) and control group (conventional surgery, n = 12). Patient demographics, fracture characteristics, operation time, incision length, and postoperative complications were then collected. The Hospital for Special Surgery (HSS) scores were recorded at the last follow-up visit. Results: The average surgical time was 52.2 (41-73) min in the experimental group and 71.2 (45-103) min in the control group. In addition, the mean total incision length was 13.8 (11-17) cm in the experimental group and 16.3 (14-19) cm in the control group. The average HHS scores at the final follow-up were 86.3 (78-93) and 82.7 (76-90) in the experimental group and control group, respectively. Conclusion: It was found that double reverse traction closed reduction combined with minimally invasive fixation can provide good repositioning results and functional extremity. Moreover, patients tolerate postoperative functional knee exercises well.

Proximal femoral bionic nail (PFBN)-an innovative surgical method for unstable femoral intertrochanteric fractures.

PURPOSE: Intertrochanteric femoral fractures (IFF) are one of the most common traumatic conditions, but there are no established treatment methods for this condition due to implant failure and re-operation rates. The proximal femoral bionic nail (PFBN), which is a new design of the cephalomedullary nail, was developed by our team. The objective of this study was to assess the clinical and radiographic outcomes of PFBN in patients with unstable IFF. METHODS: From October 2020 to August 2021, 12 patients diagnosed with unstable IFF (31-A2, 3) were treated with PFBN at the Third Hospital of Hebei Medical University. We evaluated the clinical therapeutic effects of this treatment by measuring peri-operative indicators and post-operative complications. Clinical outcomes, specific radiographic parameters, and post-operative complications were collected and analyzed within the first post-operative year. RESULTS: The average age of the patients was 72.4 ± 16.1 years (five males and seven females). The mean operation time was 90.4 ± 16.0 min, whereas the operation time of 31-A2 fractures (83.1 ± 12.2 min) was shorter than that of 31-A3 fractures (105.0 ± 12.9 min) (p < 0.05). The blood loss was 175 ml (range: 50 to 500 ml), and the length of hospitalization was 10.0 ± 1.9 days. The prognosis evaluation was assessed at three, six and 12 months after the operation; for these time points, the Harris hip scores were 69.6 ± 4.1, 77.8 ± 3.8, and 82.6 ± 4.6, respectively, and the Parker-Palmer scores were 5.3 (5.0, 7.0), 6.3 (5.3, 7.0), and 7.8 (7.0, 8.0), respectively. CONCLUSION: PFBN has shown advantages in the treatment of unstable IFF (particularly in geriatric patients) and possesses both stability and safety. This innovative method may provide a new option for treating unstable IFFs.

Aging induces severe SIV infection accompanied by an increase in follicular CD8+ T cells with overactive STAT3 signaling.

The number of elderly people living with HIV is increasing globally, and the condition of this population is relatively complicated due to the dual effects of aging and HIV infection. However, the impact of HIV infection combined with aging on the immune homeostasis of secondary lymphoid organs remains unclear. Here, we used the simian immunodeficiency virus mac239 (SIVmac239) strain to infect six young and six old Chinese rhesus macaques (ChRMs) and compared the infection characteristics of the two groups in the chronic stage through multiplex immunofluorescence staining of lymph nodes. The results showed that the SIV production and CD4/CD8 ratio inversion in old ChRMs were more severe than those in young ChRMs in both the peripheral blood and the lymph nodes, especially when a large number of CD8+ T cells infiltrated the follicles and germinal centers. STAT3 in these follicular CXCR5+CD8+ T cells was highly activated, with high expression of granzyme B, which might be caused by the severe inflammatory milieu in the follicles of old ChRMs. This study indicates that aging may be a cofactor involved in SIV-induced immune disorders in secondary lymphoid tissues, affecting the effective antiviral activity of highly enriched follicular CXCR5+CD8+ cells.

A Possible Sterilizing Cure of HIV-1 Infection Without Stem Cell Transplantation.

BACKGROUND: A sterilizing cure of HIV-1 infection has been reported in 2 persons living with HIV-1 who underwent allogeneic hematopoietic stem cell transplantations from donors who were homozygous for the CCR5Δ32 gene polymorphism. However, this has been considered elusive during natural infection. OBJECTIVE: To evaluate persistent HIV-1 reservoir cells in an elite controller with undetectable HIV-1 viremia for more than 8 years in the absence of antiretroviral therapy. DESIGN: Detailed investigation of virologic and immunologic characteristics. SETTING: Tertiary care centers in Buenos Aires, Argentina, and Boston, Massachusetts. PATIENT: A patient with HIV-1 infection and durable drug-free suppression of HIV-1 replication. MEASUREMENTS: Analysis of genome-intact and replication-competent HIV-1 using near-full-length individual proviral sequencing and viral outgrowth assays, respectively; analysis of HIV-1 plasma RNA by ultrasensitive HIV-1 viral load testing. RESULTS: No genome-intact HIV-1 proviruses were detected in analysis of a total of 1.188 billion peripheral blood mononuclear cells and 503 million mononuclear cells from placental tissues. Seven defective proviruses, some of them derived from clonally expanded cells, were detected. A viral outgrowth assay failed to retrieve replication-competent HIV-1 from 150 million resting CD4+ T cells. No HIV-1 RNA was detected in 4.5 mL of plasma. LIMITATIONS: Absence of evidence for intact HIV-1 proviruses in large numbers of cells is not evidence of absence of intact HIV-1 proviruses. A sterilizing cure of HIV-1 can never be empirically proved. CONCLUSION: Genome-intact and replication-competent HIV-1 were not detected in an elite controller despite analysis of massive numbers of cells from blood and tissues, suggesting that this patient may have naturally achieved a sterilizing cure of HIV-1 infection. These observations raise the possibility that a sterilizing cure may be an extremely rare but possible outcome of HIV-1 infection. PRIMARY FUNDING SOURCE: National Institutes of Health and Bill & Melinda Gates Foundation.

Genome-wide identification of HSF family in peach and functional analysis of PpHSF5 involvement in root and aerial organ development.

BACKGROUND: Heat shock factors (HSFs) play important roles during normal plant growth and development and when plants respond to diverse stressors. Although most studies have focused on the involvement of HSFs in the response to abiotic stresses, especially in model plants, there is little research on their participation in plant growth and development or on the HSF (PpHSF) gene family in peach (Prunus persica). METHODS: DBD (PF00447), the HSF characteristic domain, was used to search the peach genome and identify PpHSFs. Phylogenetic, multiple alignment and motif analyses were conducted using MEGA 6.0, ClustalW and MEME, respectively. The function of PpHSF5 was confirmed by overexpression of PpHSF5 into Arabidopsis. RESULTS: Eighteen PpHSF genes were identified within the peach genome. The PpHSF genes were nonuniformly distributed on the peach chromosomes. Seventeen of the PpHSFs (94.4%) contained one or two introns, except PpHSF18, which contained three introns. The in silico-translated PpHSFs were classified into three classes (PpHSFA, PpHSFB and PpHSFC) based on multiple alignment, motif analysis and phylogenetic comparison with HSFs from Arabidopsis thaliana and Oryza sativa. Dispersed gene duplication (DSD at 67%) mainly contributed to HSF gene family expansion in peach. Promoter analysis showed that the most common cis-elements were the MYB (abiotic stress response), ABRE (ABA-responsive) and MYC (dehydration-responsive) elements. Transcript profiling of 18 PpHSFs showed that the expression trend of PpHSF5 was consistent with shoot length changes in the cultivar 'Zhongyoutao 14'. Further analysis of the PpHSF5 was conducted in 5-year-old peach trees, Nicotiana benthamiana and Arabidopsis thaliana, respectively. Tissue-specific expression analysis showed that PpHSF5 was expressed predominantly in young vegetative organs (leaf and apex). Subcellular localization revealed that PpHSF5 was located in the nucleus in N. benthamiana cells. Two transgenic Arabidopsis lines were obtained that overexpressed PpHSF5. The root length and the number of lateral roots in the transgenic seedlings were significantly less than in WT seedlings and after cultivation for three weeks. The transgenic rosettes were smaller than those of the WT at 2-3 weeks. The two transgenic lines exhibited a dwarf phenotype three weeks after transplanting, although there was no significant difference in the number of internodes. Moreover, the PpHSF5-OE lines exhibited enhanced thermotolerance. These results indicated that PpHSF5 might be act as a suppresser of growth and development of root and aerial organs.

Application of a double reverse traction repositor in the retrograde intramedullary nailing of distal femur fractures.

OBJECTIVE: The purpose of this prospective study was to introduce the application of a double reverse traction repositor (DRTR) in the retrograde intramedullary nailing (RE-IMN) of AO/OTA 33A distal femur fractures. PATIENTS AND METHODS: A total of 27 patients with AO/OTA type 33A distal femur fractures who were admitted from January 2015 to May 2017 to a level I trauma center of a tertiary university hospital were enrolled in this prospective study. A DRTR was used to facilitate RE-IMN for the reduction of distal femur fractures in all patients. The demographic and fracture characteristics, surgical data, postoperative complications, and prognostic indicators of 24 patients were recorded. RESULTS: The DRTR helped achieve and maintain the reduction of all distal femur fractures in the present study. All surgeries were conducted by closed reduction, and excellent alignment was observed in the postoperative X-ray images. In the present study, 18 males and 6 females were included, and the average age of all patients was 51.3 years (range, 24-68 years). The mean operation time, intraoperative blood loss, intraoperative fluoroscopy time, and length of postoperative hospital stay were 137 min (range from 80 to 210 min), 320 ml (range from 200 to 600 ml), 28 (from 24 to 33), and 9 days (from 5 to 14 days), respectively. Eleven patients were found to have postoperative deep venous thrombosis before discharge. No cases of wound infection were observed. No cases of nonunion or malunion were observed. The average follow-up duration was 21 months (18-30 months). The average HHS, LKFS, and VAS scores at the 1-year follow-up were 89.9 (86-97), 79.1 (75-87), and 2.1 (from 0 to 5). No complications associated with DRTR were found. CONCLUSIONS: A DRTR can be successfully applied in the treatment of distal femur fractures with RE-IMN, and it can not only help achieve or maintain the reduction of distal femur fractures with closed methods but also promote fixation with RE-IMN.

Traction methods in the retrograde intramedullary nailing of femur shaft fractures: the double reverse traction repositor or manual traction.

OBJECTIVE: The purpose of this prospective study was to compare the double reverse traction repositor (DRTR) and manual traction in retrograde intramedullary nailing (RE-IMN) for femoral shaft fractures. PATIENTS AND METHODS: Seventy-seven patients with femur shaft fractures were randomized to undergo surgery with either DRTR or manual traction (MT) to facilitate RE-IMN between January 2018 and January 2019. Demographics, fracture characteristics, surgical data, post-operative complications, and functional outcomes were assessed. Data from 72 patients completing the final follow-up (12 months) were analysed in this study. RESULTS: The average number of intra-operative perspectives in the DRTR group was 27.7, which was significantly reduced compared with that in the MT group (31.3, p < 0.001). Fewer assistants were required in the DRTR group compared with the MT group (1.1 vs 1.9, p < 0.001). Fewer patients with open reduction were discovered in the DRTR group compared with the MT group (2.8 vs 19.4, p=0.024). Demographics, fracture characteristics, other surgical data, and prognostic parameters were comparative between the two groups. CONCLUSIONS: The DRTR can be effectively and safely used to treat femur shaft fractures with RE-IMN. The DRTR achieves similar results as MT and is also superior to MT in terms of intra-operative perspectives, the number of assistants, and the open reduction rate.

Epidemiological investigation of hospitalized patients with traumatic fractures: a cross-sectional study.

OBJECTIVE: This study was performed to explore major risk factors for traumatic fracture by comparing related data of hospitalized patients with traumatic fracture and patients with lumbar disc herniation. METHODS: Patients with traumatic fracture and patients with lumbar disc herniation requiring surgical treatment in the orthopedics department of our hospital from March to May 2018 were divided into a fracture group and a non-fracture group. Clinical data were collected from the two groups by questionnaires. Major risk factors for traumatic fracture were analyzed using multivariate logistic regression. RESULTS: Univariate analysis showed statistically significant differences in family history of fracture, smoking history, drinking history, sex, sleep duration, chronic disease history, osteoporosis history, age, body mass index, occupation, and education level between the two groups. Multivariate logistic regression analysis showed that patients aged 25 to 44 years were more prone to traumatic fracture than patients aged ≥65 years, male patients were more prone to fracture than female patients, drinking alcohol was a risk factor for traumatic fracture, and sufficient sleep duration (>7 hours/night) was a protective factor for traumatic fracture. CONCLUSION: Young age, male sex, and drinking are risk factors for traumatic fracture, whereas sufficient sleep duration is a protective factor.

Loss of Bcl-6-Expressing T Follicular Helper Cells and Germinal Centers in COVID-19.

Humoral responses in coronavirus disease 2019 (COVID-19) are often of limited durability, as seen with other human coronavirus epidemics. To address the underlying etiology, we examined post mortem thoracic lymph nodes and spleens in acute SARS-CoV-2 infection and observed the absence of germinal centers and a striking reduction in Bcl-6+ germinal center B cells but preservation of AID+ B cells. Absence of germinal centers correlated with an early specific block in Bcl-6+ TFH cell differentiation together with an increase in T-bet+ TH1 cells and aberrant extra-follicular TNF-α accumulation. Parallel peripheral blood studies revealed loss of transitional and follicular B cells in severe disease and accumulation of SARS-CoV-2-specific "disease-related" B cell populations. These data identify defective Bcl-6+ TFH cell generation and dysregulated humoral immune induction early in COVID-19 disease, providing a mechanistic explanation for the limited durability of antibody responses in coronavirus infections, and suggest that achieving herd immunity through natural infection may be difficult.

Distinct viral reservoirs in individuals with spontaneous control of HIV-1.

Sustained, drug-free control of HIV-1 replication is naturally achieved in less than 0.5% of infected individuals (here termed 'elite controllers'), despite the presence of a replication-competent viral reservoir1. Inducing such an ability to spontaneously maintain undetectable plasma viraemia is a major objective of HIV-1 cure research, but the characteristics of proviral reservoirs in elite controllers remain to be determined. Here, using next-generation sequencing of near-full-length single HIV-1 genomes and corresponding chromosomal integration sites, we show that the proviral reservoirs of elite controllers frequently consist of oligoclonal to near-monoclonal clusters of intact proviral sequences. In contrast to individuals treated with long-term antiretroviral therapy, intact proviral sequences from elite controllers were integrated at highly distinct sites in the human genome and were preferentially located in centromeric satellite DNA or in Krüppel-associated box domain-containing zinc finger genes on chromosome 19, both of which are associated with heterochromatin features. Moreover, the integration sites of intact proviral sequences from elite controllers showed an increased distance to transcriptional start sites and accessible chromatin of the host genome and were enriched in repressive chromatin marks. These data suggest that a distinct configuration of the proviral reservoir represents a structural correlate of natural viral control, and that the quality, rather than the quantity, of viral reservoirs can be an important distinguishing feature for a functional cure of HIV-1 infection. Moreover, in one elite controller, we were unable to detect intact proviral sequences despite analysing more than 1.5 billion peripheral blood mononuclear cells, which raises the possibility that a sterilizing cure of HIV-1 infection, which has previously been observed only following allogeneic haematopoietic stem cell transplantation2,3, may be feasible in rare instances.

Effect of pH or Metal Ions on the Oil/Water Interfacial Behavior of Humic Acid Based Surfactant.

Humic acid, a kind of widespread organic macromolecule on earth, is naturally formed through the microbial biodegradation of plant, animal, and microorganism residues. Because of the large number of active functional groups (phenolic hydroxyl and carboxyl), humic acid has been considered as a biocompatible, green, and low-cost biosurfactant recently. In this work, based on the sensitivity of humic acid to the external chemical environment, the oil/water interfacial behavior of sodium humate at different pH or in the presence of metal ions is closely investigated. Sodium humate is significantly enriched toward the oil/water interface at either low pH or high metal-ion concentration to adjust the properties of the prepared emulsion, but the mechanisms are proved to be different when considering the influence of pH and metal ions. Besides, to the best of our knowledge, humic acid based surfactant is proposed as a Pickering emulsifier for the first time, known as solid surfactant. This work promises the great potential of humic acid as a natural environment-responsive surfactant and has important implications for the application of humic acid based surfactant in industry and understanding of the role of humic acid in the natural environment.

Genome-wide identification and transcriptome profiling reveal that E3 ubiquitin ligase genes relevant to ethylene, auxin and abscisic acid are differentially expressed in the fruits of melting flesh and stony hard peach varieties.

BACKGROUND: Ubiquitin ligases (E3) are the enzymes in the ubiquitin/26S proteasome pathway responsible for targeting proteins to the degradation pathway and play major roles in multiple biological activities. However, the E3 family and their functions are yet to be identified in the fruit of peach. RESULTS: In this study, genome-wide identification, classification and characterization of the E3 ligase genes within the genome of peach (Prunus persica) was carried out. In total, 765 E3 (PpE3) ligase genes were identified in the peach genome. The PpE3 ligase genes were divided into eight subfamilies according to the presence of known functional domains. The RBX subfamily was not detected in peach. The PpE3 ligase genes were not randomly distributed among the 8 chromosomes, with a greater concentration on the longer chromosomes. The primary mode of gene duplication of the PpE3 ligase genes was dispersed gene duplication (DSD). Four subgroups of the BTB subfamily never characterized before were newly identified in peach, namely BTBAND, BTBBL, BTBP and BTBAN. The expression patterns of the identified E3 ligase genes in two peach varieties that display different types of fruit softening (melting flesh, MF, and stony hard, SH) were analyzed at 4 different stages of ripening using Illumina technology. Among the 765 PpE3 ligase genes, 515 (67.3%) were expressed (FPKM > 1) in the fruit of either MF or SH during fruit ripening. In same-stage comparisons, 231 differentially expressed genes (DEGs) were identified between the two peach cultivars. The number of DEGs in each subfamily varied. Most DEGs were members of the BTB, F-box, U-box and RING subfamilies. PpE3 ligase genes predicted to be involved in ethylene, auxin, or ABA synthesis or signaling and DNA methylation were differentially regulated. Eight PpE3 ligase genes with possible roles in peach flesh texture and fruit ripening were discussed. CONCLUSIONS: The results of this study provide useful information for further understanding the functional roles of the ubiquitin ligase genes in peach. The findings also provide the first clues that E3 ligase genes may function in the regulation of peach ripening.

Posterior paraspinal muscle versus post-middle approach for the treatment of thoracolumbar burst fractures: A randomized controlled trial.

BACKGROUND: This randomized controlled trial (RCT) aimed to compare the clinical outcomes of thoracolumbar burst fractures (TLBFs) treated with open reduction and internal fixation via the posterior paraspinal muscle approach (PPMA) and the post-middle approach (PA). METHODS: Patients with a traumatic single-level TLBFs (T10-L2), treated at our hospital between December 2009 and December 2014, were randomly allocated to Group A (PPMA) and Group B (PA). Sex, age, time from injury to surgery, the American Spinal Injury Association Impairment Scale score (ASIAIS), comorbidities, vertebral level, pre- and postoperative kyphotic angle (KA), visual analog scale (VAS) pain score, and the Oswestry Disability Index (ODI) scores were included in the analysis. Operative time, intraoperative blood loss, x-ray exposure time, postoperative drainage volume, superficial infection, and occurrence of deep infection were documented. The patients were followed up at 2 weeks; 1, 3, and 6 months; 1 and 2 years; and every 6 months thereafter. Radiological assessments were performed to assess fracture union and detect potential loosening and breakage of the pedicle screws and rods at each follow-up. Postoperative VAS and ODI scores were used to evaluate the clinical outcomes. RESULTS: A total of 62 patients were enrolled (30 in Group A and 32 in Group B, respectively). The operative time (P < .001) and x-ray exposure time (P < .001) in Group A were significantly longer than those in Group B. However, compared to Group B, there were less intraoperative blood loss (P < .001), lower postoperative drainage volume (P < .001), lower VAS scores (2-week (P = .029), 1-month (P = .023), 3-month (P = .047), and 6-month follow-up (P = .010)), and lower ODI scores (2-week, P = .010; 1-month, P < .001; 3-month, P = .028; and 6-month follow-up, P = .033) in Group A. CONCLUSIONS: Although PPMA required a longer operative time and x-ray exposure time, PPMA provided several advantages over PA, including less intra-operative blood loss and lower postoperative drainage volume, and greater satisfaction with postoperative pain relief and functional improvement, than PA, especially at the 6-month follow-up after surgery. Further high-quality multicenter studies are warranted to validate our findings.

α3-Deletion Isoform of HLA-A11 Modulates Cytotoxicity of NK Cells: Correlations with HIV-1 Infection of Cells.

Alternative splicing occurs frequently in many genes, especially those involved in immunity. Unfortunately, the functions of many alternatively spliced molecules from immunologically relevant genes remain unknown. Classical HLA-I molecules are expressed on almost all nucleated cells and play a pivotal role in both innate and adaptive immunity. Although splice variants of HLA-I genes have been reported, the details of their functions have not been reported. In the current study, we determined the characteristics, expression, and function of a novel splice variant of HLA-A11 named HLA-A11svE4 HLA-A11svE4 is located on the cell surface without ß2-microglobulin (ß2m). Additionally, HLA-A11svE4 forms homodimers as well as heterodimers with HLA-A open conformers, instead of combining with ß2m. Moreover, HLA-A11svE4 inhibits the activation of NK cells to protect target cells. Compared with ß2m and HLA-A11, the heterodimer of HLA-A11svE4 and HLA-A11 protected target cells from lysis by NK cells more effectively. Furthermore, HLA-AsvE4 expression was upregulated by HIV-1 in vivo and by HSV, CMV, and hepatitis B virus in vitro. In addition, our findings indicated that HLA-A11svE4 molecules were functional in activating CD8+ T cells through Ag presentation. Taken together, these results suggested that HLA-A11svE4 can homodimerize and form a novel heterodimeric complex with HLA-A11 open conformers. Furthermore, the data are consistent with HLA-A11svE4 playing a role in the immune escape of HIV-1.