Rapid Detection of Uropathogens Using an Integrated Multiplex Digital Nucleic Acid Detection Assay Powered by a Digital-to-Droplet Microfluidic Device.

The digital nucleic acid detection assay features the capability of absolute quantitation without the need for calibration, thereby facilitating the rapid identification of pathogens. Although several integrated digital nucleic acid detection techniques have been developed, there are still constraints in terms of automation and analysis throughput. To tackle these challenges, this study presents a digital-to-droplet microfluidic device comprising a digital microfluidics (DMF) module at the bottom and a droplet microfluidics module at the top. Following sample introduction, the extraction of nucleic acid and the dispensation of nucleic acid elution for mixing with the multiple amplification reagents are carried out in the DMF module. Subsequently, the reaction droplets are transported to the sample inlet of the droplet microfluidic module via a liquid outlet, and then droplet generation in four parallel units within the droplet microfluidics module is actuated by negative pressure generated by a syringe vacuum. The digital-to-droplet microfluidic device was employed to execute an integrated multiplex digital droplet nucleic acid detection assay (imDDNA) incorporating loop-mediated isothermal amplification (LAMP). This assay was specifically designed to enable simultaneous detection of four uropathogens, namely, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterococcus faecalis. The entire process of the imDDNA is completed within 75 min, with a detection range spanning 5 orders of magnitude (9.43 × 10-2.86 × 104 copies µL-1). The imDDNA was employed for the detection of batched clinical specimens, showing a consistency of 91.1% when compared with that of the conventional method. The imDDNA exhibits simplicity in operation and accuracy in quantification, thus offering potential advantages in achieving rapid pathogen detection.

Rapid and sensitive detection of heart-type fatty acid binding protein using aggregation-induced emission nanoparticles on digital microfluidics workstation.

Early and rapid diagnostic of acute myocardial infarction (AMI) during its developing stage is crucial due to its high fatality rate. Heart-type fatty acid binding protein (h-FABP) is an ideal biomarker for the quantitative diagnosis of AMI, surpassing traditional markers such as myoglobin, creatine phosphokinase-MB, and troponin in terms of sensitivity, specificity, and prognostic value. To obtain diagnostic and prognostic information, a precise and fully quantitative measurement of h-FABP is essential, typically achieved through an immunosorbent assay like the enzyme-linked immunosorbent assay. Nevertheless, this method has several limitations, including extended detection time, complex assay procedures, the necessity for skilled technicians, and challenges in implementing automated detection. This research introduces a novel biosensor, utilizing aggregation-induced emission nanoparticles (AIENPs) and integrated with a digital microfluidic (DMF) workstation, designed for the sensitive, rapid, and automated detection of h-FABP in low-volume serum samples. AIENPs and magnetic beads in nanoscale were served as the capture particles and the fluorescent probe, which were linked covalently to anti-h-FABP antibodies respectively. The approach was based on a sandwich immunoassay and performed on a fully automated DMF workstation with assay time by 15 min. We demonstrated the determination of h-FABP in serum samples with detection limit of 0.14 ng/mL using this biosensor under optimal condition. Furthermore, excellent correlations (R2 = 0.9536, n = 50) were obtained between utilizing this biosensor and commercialized ELISA kits in clinical serum detecting. These results demonstrate that our flexible and reliable biosensor is suitable for direct integration into clinical diagnostics, and it is expected to be promising diagnostic tool for early detection and screening tests as well as prognosis evaluation for AMI patients.

Targeting AURKA to induce synthetic lethality in CREBBP-deficient B-cell malignancies via attenuation of MYC expression.

Loss-of-function mutations in CREBBP, which encodes for a histone acetyltransferase, occur frequently in B-cell malignancies, highlighting CREBBP deficiency as an attractive therapeutic target. Using established isogenic cell models, we demonstrated that CREBBP-deficient cells are selectively vulnerable to AURKA inhibition. Mechanistically, we found that co-targeting CREBBP and AURKA suppressed MYC transcriptionally and post-translationally to induce replication stress and apoptosis. Inhibition of AURKA dramatically decreased MYC protein level in CREBBP-deficient cells, implying a dependency on AURKA to sustain MYC stability. Furthermore, in vivo studies showed that pharmacological inhibition of AURKA was efficacious in delaying tumor progression in CREBBP-deficient cells and was synergistic with CREBBP inhibitors in CREBBP-proficient cells. Our study sheds light on a novel synthetic lethal interaction between CREBBP and AURKA, indicating that targeting AURKA represents a potential therapeutic strategy for high-risk B-cell malignancies harboring CREBBP inactivating mutations.

Elevated serum level of progranulin is associated with increased mortality in critically ill patients with candidemia.

Candidemia is a severe disease with high mortality in both intensive care unit (ICU) and non-ICU settings. Considering that progranulin (PGRN) is a potential therapeutic target for the candidemia caused by Candida albicans, we determined the serum level of PGRN after candidemia and evaluated its association with mortality. A retrospective discovery cohort (62 patients) and a validation cohort (70 patients) were enrolled. Blood was collected on day of first blood culture positivity for C. albicans, and serum PGRN levels were then measured. In the discovery cohort, all serum PGRN studied were expressed at higher levels in candidemia patients than in bacteremia patients and healthy volunteers, non-survivors presented with significantly higher serum PGRN concentrations when compared with survivors. Serum PGRN concentration was associated with 30-day mortality and patients at a higher risk of death showed higher serum PGRN levels. These results were confirmed in the independent validation cohort. Interestingly, in vitro study demonstrated that macrophages, neutrophils and lymphocytes may be the major source of PGRN production after C. albicans infection instead of epithelial cells. Our findings highlight that serum PGRN appears as a biomarker in candidemia patients and as a promising tool for mortality risk stratification in managing candidemia.

Musashi-2 (MSI2) promotes neuroblastoma tumorigenesis through targeting MYC-mediated glucose-6-phosphate dehydrogenase (G6PD) transcriptional activation.

Neuroblastoma (NB) is the deadliest pediatric solid tumor due to its rapid proliferation. Aberrant expression of MYCN is deemed as the most remarkable feature for the predictive hallmark of NB progression and recurrence. However, the phenomenon that only detection of MYCN in the nearly 20% of NB patients hints that there should be other vital oncogenes in the progression of NB. Here, we firstly show that MSI2 mRNA is augmented by analyzing public GEO datasets in the malignant stage according to International Neuroblastoma Staging System (INSS) stages. Although accumulating evidences uncover the emerging roles of MSI2 in several cancers, the regulatory functions and underlying mechanisms of MSI2 in NB remain under-investigated. Herein, we identified that high-expressed MSI2 and low-expressed n-Myc group account for 43.1% of total NB clinical samples (n = 65). Meanwhile, MSI2 expression is profoundly upregulated along with NB malignancy and negatively associated with the survival outcome of NB patients in the NB tissue microarray (NB: n = 65; Ganglioneuroblastoma: n = 31; Ganglioneuroma: n = 27). In vitro, our results revealed that MSI2 promoted migration, invasion, and proliferation of NB cells via enhancing pentose phosphate pathway. Mechanistically, MSI2 upregulated the key enzyme glucose-6-phosphate dehydrogenase (G6PD) via directly binding to 3'-untranslated regions of c-Myc mRNA to facilitate its stability, resulting in enhancing pentose phosphate pathway. Our findings reveal that MSI2 promotes pentose phosphate pathway via activating c-Myc-G6PD signaling, suggesting that MSI2 exhibits a novel and powerful target for the diagnosis and treatment of NB.

Distribution and Drug Resistance of Bacterial Infection in Hospitalized Patients at the Respiratory Department before and after the COVID-19 Pandemic in Guangzhou, China.

Since COVID-19 might have a lasting impact on global public health, it is crucial to analyze its effect on drug-resistant bacterial infections in the respiratory system for the prevention and control of hospital infections. This work aimed to investigate the impact of the COVID-19 outbreak on the clinical distribution and antibiotic resistance of bacterial infection among hospitalized patients in the respiratory unit in order to establish strategies to control antibiotic-resistant infections. Electronic clinical data registry records from 2018 to 2022 were retrospectively analyzed. A total of 36,829 clinical specimens, including sputum, bronchoalveolar lavage fluid, blood, and urine, were collected from 16,073 patients admitted to the Guangzhou First People's Hospital from January 2018 to December 2022. Among them, 2209 samples were culture-positive. The bacterial isolation rates of different types of samples showed a similar trend from 2019 to 2022, with an increase in 2020 and 2022 and a decrease in 2021. Different bacterial species were separated from different types of samples. The most reported pathogens were identified in sputum samples. Gram-positive isolates were prevalent in urine samples, while Gram-negative bacilli were the predominant pathogenic bacteria isolated from respiratory tract and blood samples. Pseudomonas aeruginosa (P. aeruginosa), Acinetobacter baumannii (A. baumannii) complex, and Klebsiella pneumoniae (K. pneumoniae) were the most abundant Gram-negative bacteria in sputum samples, of which A. baumannii complex had the highest resistance to all tested antibiotics except colistin. Notably, there has been a substantial prevalence of carbapenem-resistant P. aeruginosa, A. baumannii, and K. pneumoniae in the past five years. This alarming situation calls for greater attention and precaution with prescribed antibiotics to limit the generation and spread of new multidrug-resistant bacteria and improve therapeutic management.

Development of Microfluidic Chip-Based Loop-Mediated Isothermal Amplification (LAMP) Method for Detection of Carbapenemase Producing Bacteria.

The rapid and accurate diagnostic methods to identify carbapenemase-producing organisms (CPO) is of great importance for controlling the CPO infection. Herein, we have developed a microfluidic chip-based technique to detect CPO and assessed its clinical value in detecting CPO directly from blood cultures (BCs). The detection performance of the microfluidic chip-based LAMP amplification method was analyzed retrospectively on a collection of 192 isolates including molecularly characterized 108 CPO and 84 non-CPO and prospectively on a collection of 133 positive BCs with or without CPO suspicion, respectively. In the retrospective study, the microfluidic chip-based LAMP amplification method exhibited 87.5% accuracy (95% CI [82.0-91.5]), 97.7% sensitivity (95% CI [91.2-99.6]), 78.8% specificity (95% CI [69.5-86.0]), 79.6% positive predictive value (PPV) (95% CI [70.6-86.5]) and 97.6% negative predictive value (NPV) (95% CI [90.9-99.6]). Among the 192 isolates, 22 (11.5%) false-positives (FP) and 2 (1.0%) false negatives (FN) were observed. In the prospective study, the 133 routine isolates of positive BCs including 18 meropenem-resistant CPO and 115 non-CPO were assessed, and 4 FP were observed in non-CPO and CPO, respectively. The current method showed a total detection performance of 94.0% accuracy (95% CI [88.4-97.1]), 100.0% sensitivity (95% CI [73.2-100.0]), 93.2% specificity (95% CI [86.7-96.8]), 63.6% PPV (95% CI [40.8-82.0]) and 100.0% NPV (95% CI [95.8-100.0]). In summary, the microfluidic chip-based LAMP amplification method is reliable for the rapid screening and detection of CPO with high accuracy, sensitivity, and specificity, and could easily be implemented in clinical microbiology laboratories. IMPORTANCE Rapid and accurate identification of CPO may reduce the genetic exchanges among bacteria and prevent further dissemination of carbapenemases to non-CPO. The current method had designed microfluidic chip-based LAMP amplification method for multiplex detection of carbapenemase genes and evaluated the detection performance of the newly method. The current method can rapidly screen and detect CPO with high accuracy, sensitivity, and specificity, and could easily be implemented in clinical microbiology laboratories, as this will reduce the carbapenem resistance issues worldwide.

Epstein-Barr virus-encoded microRNA BART22 serves as novel biomarkers and drives malignant transformation of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy ubiquitously associated with Epstein-Barr virus (EBV). EBV generates various viral microRNAs (miRNAs) by processing the BHRF1 and BamHI A rightward (BART) transcripts. These BART miRNAs are abundantly expressed in NPC, but their functions and molecular mechanisms remain largely unknown. Our study found that the EBV-encoded microRNA BART-22 was significantly upregulated in NPC tissues and positively correlated with tumor progression. Furthermore, we found that EBV-miR-BART-22 was a significant predictor of poor prognosis in NPC. A reliable nomogram model to predict the preoperative overall survival (OS) of NPC patients was established. The area under the receiver operating characteristic (ROC) curve value for 5-year survival was 0.91. Elevated levels of EBV-miR-BART-22 significantly promoted the epithelial-mesenchymal transition (EMT) and metastasis of NPC cells in vivo and in vitro. We found that EBV-miR-BART-22 directly targets the 3'-UTR of MOSPD2 mRNA to promote the EMT and metastasis of NPC cells by activating the Wnt/ß-catenin signaling pathway. Our findings provide a potential prognostic biomarker and new insight into the molecular mechanisms of NPC metastasis.

IL-27 induces LL-37/CRAMP expression from intestinal epithelial cells: implications for immunotherapy of Clostridioides difficile infection.

Clostridioides difficile infection is currently the leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis worldwide. Cathelicidins, a major group of natural antimicrobial peptides, have antimicrobial and immunomodulatory activities in Clostridioides difficile infection. Here, we have shown that cytokine IL-27 induced human cathelicidin antimicrobial peptide (LL-37) expression in primary human colonic epithelial cells. IL-27 receptor-deficient mice had impaired expression of cathelicidin-related antimicrobial peptide (CRAMP, mouse homolog for human LL-37) after Clostridioides difficile infection, and restoration of CRAMP improved Clostridium difficile clearance and reduced mortality in IL-27 receptor-deficient mice after Clostridioides difficile challenge. In clinical samples from 119 patients with Clostridioides difficile infection, elevated levels of IL-27 were positively correlated with LL-37 in the sera and stools. These findings suggest that IL-27 may be involved in host immunity against Clostridioides difficile infection via induction of LL-37/CRAMP. Therefore, IL-27-LL-37 axis may be a valuable pathway in the development of immune-based therapy.

A pocket-sized device automates multiplexed point-of-care RNA testing for rapid screening of infectious pathogens.

Rapid screening of infectious pathogens at the point-of-care (POC) is ideally low-cost, portable, easy to use, and capable of multiplex detection with high sensitivity. However, satisfying all these features in a single device without compromise remains a challenging task. Here, we introduce an ultraportable, automated RNA amplification testing device that allows rapid screening of infectious pathogens from clinical samples. In this device, 3D-printed structural parts incorporated with off-the-shelf mechanic/electronic components are utilized to create an inexpensive and automated droplet manipulation platform. On this platform, a simple configuration that couples a linear displacement of the chip with a tunable magnet array allows parallel and versatile droplet operations, including mixing, splitting, transporting, and merging. By exploiting a multi-channel droplet array chip to preload necessary reagents in "water-in-oil" format, bacteria lysis, RNA extraction and amplification are seamlessly integrated and implemented by the combination of droplet operations. Furthermore, visual readout and geometrically-multiplexed quantitative detection are provided by an integrated wireless video camera-enabled wide-field fluorescence imaging. We demonstrated that this droplet-based device could have a shorter RNA extraction time (12 min) and lower detection limits for pathogenic RNA (approaching to 102 copies per reaction). We also verified its clinical applicability for the rapid screening of four sexually transmitted pathogens from urine specimens. Results show that the sample-to-answer assay could be completed in approximately 42 min, with 100% concordance with the laboratory-based molecular testing. The exhibiting features may render this microdevice an easily accessible POC molecular diagnostic platform for infectious disease, especially in resource-limited settings.

Upregulation of PEDF Predicts a Poor Prognosis and Promotes Esophageal Squamous Cell Carcinoma Progression by Modulating the MAPK/ERK Signaling Pathway.

Invasion and metastasis represent the primary causes of therapeutic failure in patients diagnosed with esophageal squamous cell carcinoma (ESCC). The lack of effective treatment strategies for metastatic ESCC is the major cause of the low survival rate. Therefore, it is crucial to understand the molecular mechanisms underlying ESCC metastasis and identify potential biomarkers for targeted therapy. Herein, we reported that PEDF is significantly correlated with tumor cell invasion and metastasis in ESCC. The high expression of PEDF is an independent unfavorable prognostic factor for ESCC patients' overall survival (OS). We successfully developed and verified a nomogram to predict the preoperative OS of ESCC patients, and the actual and nomogram-predicted 1-, 3-, and 5-year survival rates had good consistency. The receiver operating characteristic (ROC) curve showed that the area under the curve (AUC) values for 1-, 3- and 5- survival were 0.764, 0.871, and 0.91, respectively. Overexpression of PEDF significantly promoted the migration and invasion of ESCC cells in vitro, while silencing PEDF yielded the opposite effects. Elevated levels of PEDF altered the expression of proteins involved in epithelial-mesenchymal transition (EMT), as indicated by the upregulation of N-cadherin and the downregulation of α-catenin and E-cadherin in ESCC cells. Mechanistically, PEDF promoted tumor cell motility and EMT by activating the MAPK/ERK signaling pathway. In conclusion, our results reveal that PEDF is involved in ESCC metastasis and could act as a prognostic factor for ESCC. Our research provides a fresh perspective into the mechanism of ESCC metastasis.

Misidentification of Burkholderia pseudomallei, China.

We report a case of melioidosis in China and offer a comparison of 5 commercial detection systems for Burkholderia pseudomallei. The organism was misidentified by the VITEK 2 Compact, Phoenix, VITEK mass spectrometry, and API 20NE systems but was eventually identified by the Bruker Biotyper system and 16S rRNA sequencing.

TLR7 Expression Aggravates Invasive Pulmonary Aspergillosis by Suppressing Anti-Aspergillus Immunity of Macrophages.

Toll-like receptors (TLRs) play a critical role in early immune recognition of Aspergillus, which can regulate host defense during invasive pulmonary Aspergillosis (IPA). However, the role of TLR7 in the pathogenesis of IPA remains unknown. In this study, an in vivo model of IPA was established to investigate the contribution of TLR7 to host anti-Aspergillus immunity upon invasive pulmonary Aspergillus fumigatus infection. The effects of TLR7 on phagocytosis and killing capacities of A. fumigatus by macrophages and neutrophils were investigated in vitro We found that TLR7 knockout mice exhibited lower lung inflammatory response and tissue injury, higher fungal clearance, and greater survival in an in vivo model of IPA compared with wild-type mice. TLR7 activation by R837 ligand led to wild-type mice being more susceptible to invasive pulmonary Aspergillus fumigatus infection. Macrophages, but not neutrophils, were required for the protection against IPA observed in TLR7 knockout mice. Mechanistically, TLR7 impaired phagocytosis and killing of A. fumigatus by macrophages but not neutrophils. Together, these data identify TLR7 as an important negative regulator of anti-Aspergillus innate immunity in IPA, and we propose that targeting TLR7 will be beneficial in the treatment of IPA.

Microbiota-driven interleukin-17 production provides immune protection against invasive candidiasis.

BACKGROUND: The intestinal microbiota plays a crucial role in human health, which could affect host immunity and the susceptibility to infectious diseases. However, the role of intestinal microbiota in the immunopathology of invasive candidiasis remains unknown. METHODS: In this work, an antibiotic cocktail was used to eliminate the intestinal microbiota of conventional-housed (CNV) C57/BL6 mice, and then both antibiotic-treated (ABX) mice and CNV mice were intravenously infected with Candida albicans to investigate their differential responses to infection. Furthermore, fecal microbiota transplantation (FMT) was applied to ABX mice in order to assess its effects on host immunity against invasive candidiasis after restoring the intestinal microbiota, and 16S ribosomal RNA gene sequencing was conducted on fecal samples from both uninfected ABX and CNV group of mice to analyze their microbiomes. RESULTS: We found that ABX mice displayed significantly increased weight loss, mortality, and organ damage during invasive candidiasis when compared with CNV mice, which could be alleviated by FMT. In addition, the level of IL-17A in ABX mice was significantly lower than that in the CNV group during invasive candidiasis. Treatment with recombinant IL-17A could improve the survival of ABX mice during invasive candidiasis. Besides, the microbial diversity of ABX mice was significantly reduced, and the intestinal microbiota structure of ABX mice was significantly deviated from the CNV mice. CONCLUSIONS: Our data revealed that intestinal microbiota plays a protective role in invasive candidiasis by enhancing IL-17A production in our model system.

Mucosal Profiling of Pediatric-Onset Colitis and IBD Reveals Common Pathogenics and Therapeutic Pathways.

Pediatric-onset colitis and inflammatory bowel disease (IBD) have significant effects on the growth of infants and children, but the etiopathogenesis underlying disease subtypes remains incompletely understood. Here, we report single-cell clustering, immune phenotyping, and risk gene analysis for children with undifferentiated colitis, Crohn's disease, and ulcerative colitis. We demonstrate disease-specific characteristics, as well as common pathogenesis marked by impaired cyclic AMP (cAMP)-response signaling. Specifically, infiltration of PDE4B- and TNF-expressing macrophages, decreased abundance of CD39-expressing intraepithelial T cells, and platelet aggregation and release of 5-hydroxytryptamine at the colonic mucosae were common in colitis and IBD patients. Targeting these pathways by using the phosphodiesterase inhibitor dipyridamole restored immune homeostasis and improved colitis symptoms in a pilot study. In summary, comprehensive analysis of the colonic mucosae has uncovered common pathogenesis and therapeutic targets for children with colitis and IBD.

Aurora kinase A stabilizes FOXM1 to enhance paclitaxel resistance in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) has a relatively poor outcome. Acquired chemoresistance is a major clinical challenge for TNBC patients. Previously, we reported that kinase-dead Aurora kinase A (Aurora-A) could effectively transactivate the FOXM1 promoter. Here, we demonstrate an additional pathway through which Aurora-A stabilizes FOXM1 by attenuating its ubiquitin in TNBC. Specifically, Aurora-A stabilizes FOXM1 in late M phase and early G1 phase of the cell cycle, which promotes proliferation of TNBC cells. Knock-down of Aurora-A significantly suppresses cell proliferation in TNBC cell lines and can be rescued by FOXM1 overexpression. We observe that paclitaxel-resistant TNBC cells exhibit high expression of Aurora-A and FOXM1. Overexpression of Aurora-A offers TNBC cells an additional growth advantage and protection against paclitaxel. Moreover, Aurora-A and FOXM1 could be simultaneously targeted by thiostrepton. Combination of thiostrepton and paclitaxel treatment reverses paclitaxel resistance and significantly inhibits cell proliferation. In conclusion, our study reveals additional mechanism through which Aurora-A regulates FOXM1 and provides a new therapeutic strategy to treat paclitaxel-resistant triple-negative breast cancer.

A Simple Fecal Bacterial Marker Panel for the Diagnosis of Crohn's Disease.

Background and Aims: Intestinal dysbiosis is implicated in the pathogenesis of Crohn's disease (CD). We evaluated fecal and sera microbial markers for clinical use in detecting CD. Methods: Fecal samples from 346 Asian subjects were collected, including 95 patients with CD, 81 patients with ulcerative colitis (UC), 65 patients with irritable bowel syndrome (IBS), and 105 healthy subjects (HS). Microbial indicators Fusobacterium nucleatum (Fn), Faecalibacterium prausnitzii (Fp), and Escherichia coli (E. coli) were identified based on a review of the literature. The relative abundance of the three bacterial markers were measured by qPCR, and two serological microbial markers (anti-Fn, anti-E. coli) were measured by ELISA. We evaluated the diagnostic performance of these microbial markers by ROC curve analysis. Results: The quantification of Fp, Fn, and E. coli of fecal samples is relatively stable when stored up to 6 h at room temperature. The significant increasing abundances of Fn were accompanied by a decline of Fp in the CD group. Fn exhibited a slightly higher diagnostic value than Fp in distinguishing CD from HS (Area Under Curve, AUC = 0.841 vs. 0.811) or irritable bowel syndrome (IBS) groups (AUC = 0.767 vs. 0.658), and the further combination of Fn and Fp improved the diagnostic value (HS, AUC = 0.867; IBS, AUC = 0.771). However, anti-E. coli and anti-Fn antibodies in serum did not possess diagnostic value for CD or UC. Conclusion: A combination of fecal Fn and Fp was identified as a valuable marker for CD diagnosis. A CD bacterial marker panel may provide a simple non-invasive approach to screen for CD.

The association between the ApoE polymorphisms and the MRI-defined intracranial lesions in a cohort of southern China population.

BACKGROUND: The apolipoprotein E (APOE) ε4 allele is considered as a risk factor for Alzheimer's disease (AD). However, the association of APOE allele with MRI evidence of intracranial lesions has not been well understood. METHODS: Quantitative real-time PCR was performed to detect the APOE genotype; MRI was examined for intracranial lesions. Their association was evaluated in a cohort of 226 AD patients and 2607 healthy individuals in southern China. RESULTS: The frequencies of ε2, ε3, and ε4 alleles were 8.0%, 82.9%, and 9.1% in the whole study population. The frequency of APOE-ε4 allele was significantly higher in the AD subjects than that in the control group (14.4% vs 8.6%, P < 0.001). We found that brain atrophy occurred at a rate of 12.3% in ε4 allele group vs 8.5% in non-ε4 genotype group, with a significance of P = 0.008. Severe brain atrophy occurred at a rate of 1.0% in ε4 allele group vs 0.2% in non-ε4 genotype group (P = 0.011). The individuals carrying APOE ε4/ε4 had an odds ratio (OR) of 7.64 (P < 0.01) for developing AD, while the APOE ε3/ε4 gene carriers had an OR of 1.47 (P = 0.031) and the OR in APOE ε2/ε3 carriers is 0.81 (P = 0.372). Interestingly, we found that the risk of ε4/ε4 allele carrier developing AD was significantly higher in male (P < 0.001) than female (P = 0.478). CONCLUSION: Compared to ε2 and ε3 alleles, the presence of APOE-ε4 allele might increase the risk for AD in a dose-dependent manner in southern China. Moreover, the presence of APOE-ε4 allele results in a higher incidence of brain atrophy.