Research progress on the roles and mechanisms of γδT cells in periodontitis / 口腔疾病防治

@#Periodontitis is a chronic infectious disease that occurs in periodontal support tissues. Plaque microorganisms are its initiating factor, while local inflammation and alveolar bone loss resulting from periodontitis are the most common causes of tooth loss. Interleukin-17 (IL-17), which plays an important role in the immune response to periodontitis, mostly originates from T helper cell 17 (Th17) and γδT cells. In periodontitis, the role of Th17 cells has been demonstrated broadly, but the role of γδT cells was not revealed until recent years. As a highly heterogeneous group of T lymphocytes, γδT cells are considered a link between innate immunity and adaptive immunity. Studies have found that γδT cells are mostly distributed in the oral epithelium near the biofilm, where they can interact with microorganisms to produce IL-17, recruit neutrophils, macrophages, etc., and participate in the host immune response to periodontitis. They also play a role in the association between periodontitis and relevant systemic diseases. In addition, γδT cells have been proven to produce tissue repair-related factors with a protective effect against periodontitis. The possible mechanism of γδT cells in periodontitis is discussed in this review.

Research progress on fluoride-releasing restorative materials for caries control / 口腔疾病防治

@#Restorative materials such as conventional glass ionomer cement (CGIC), resin-modified glass ionomer cement (RMGIC), polyacid-modified composite resin (compomer), and giomer have the properties of fluoride release and refill, which may prevent or slow down the progression of caries. The caries resistance of these materials was evaluated according to the following criteria: fluorine-releasing ability, antibacterial activity, mechanical properties and anti-aging properties. The anti-caries effect of these materials mainly depends on the effect of fluoride ions on mineralization. However, materials with strong fluorine release ability, such as CGIC, are mainly used in pediatric dentistry and temporary restoration due to their poor mechanical properties. It is difficult to achieve both fluoride ion release potential and mechanical strength, and there are few materials that can provide ideal mechanical strength while maintaining a high standard of fluoride release. The fluoride releasing and recharging capacity of CGIC, RMGIC, compomer and giomer decrease successively. The trend of material modification, to a certain extent, tends to sacrifice the fluoride release capacity of materials to maintain the ideal mechanical strength. In recent years, scholars have tried to add a variety of fillers to further enhance the anti-cracking ability of materials and add antibacterial agents to compensate for the anti-caries effect to reduce the loss of fluoride release.

Research progress on the relationship between periodontal pathogens and colorectal cancer / 口腔疾病防治

@#With the deepening of the research on the relationship between oral microbiota and systemic diseases, researchers have found that periodontitis is closely related to diabetes, cardiovascular disease, digestive system disease and other systemic diseases. Fusobacterium nucleatum (Fn) and Porphyromonas gingivalis (Pg) are common periodontal pathogens, which play a key role in the occurrence and development of periodontitis. At present, it is also found that Fn and Pg are closely related to the occurrence and development of colorectal cancer (CRC). They can affect the occurrence and development of CRC and the therapeutic effect and prognosis of CRC patients through a variety of ways. It can promote tumor cell proliferation by regulating cell division cycle and inhibiting cell apoptosis, inhibit immune cell function to mediate immune escape and tumor metastasis, and create a pro-inflammatory microenvironment suitable for tumor survival. The study of the effect of periodontal pathogens on the occurrence and development of colorectal cancer and its mechanism also allows us to think about new methods, such as vaccine development, immune agents and antibiotic use to better prevent and treat colorectal cancer and improve the prognosis of patients with colorectal cancer.

Clinical phenotypes of primary ciliary dyskinesia / 中南大学学报(医学版)

Primary ciliary dyskinesia (PCD) is a hereditary disease characterized by airway mucociliary clearance dysfunction. The estimated prevalence of PCD is 1꞉10 000 to 1꞉20 000. The main respiratory manifestations in children are cough, expectoration, chronic rhinitis, sinusitis, and chronic otitis media, while the most common symptoms in adults are chronic sinusitis, bronchiectasis, and infertility. About 50% of patients with certain PCD-related gene variants are combined with situs inversus, and the incidence of congenital heart disease is also high. The pathogenesis behind PCD is that gene variants cause structural or functional disorders of respiratory cilia and motile cilia of other organs, leading to a series of heterogeneous clinical manifestations, which makes it difficult to identify and diagnose PCD. Combining different disease screening tools and understanding the relationship between genotypes and phenotypes may facilitate early diagnosis and treatment for PCD.

Research progress on salivary exosomes and oral diseases / 口腔疾病防治

@#Salivary exosomes are extracellular vesicles with a diameter of 30-50 nm in saliva. With the development of technology in recent years, many studies have revealed that salivary exosomes play an important role in the occurrence and development of various oral diseases. For example, salivary exosomal CD9 and CD81 promote tumor cell metastasis by regulating the cell adhesion and movement, salivary exosomal miR-24-3p promotes the tumor cell proliferation by acting on PER1, and salivary exosomal programmed cell death-ligand 1 (PD-L1) mRNA inhibits the destruction of inflammatory tissue, which can be biomarkers for the diagnosis of oral cancer, periodontitis and other oral diseases. Therefore, salivary exosomes can be used as potential prognostic and diagnostic markers for oral diseases. In addition to oral diseases, such as oral cancer, periodontitis, oral lichen planus, Sjogren’s syndrome, etc., salivary exosomes are closely related to distant tumors, such as pancreatic cancer, lung cancer, and systemic diseases, such as Parkinson’s disease, inflammatory bowel disease, etc. It is of great significance to study the role of salivary exosomes in the diagnosis and treatment of oral and systemic diseases and to develop the potential of salivary exosomes as biomarkers for disease diagnosis.

Study on the antifungal effect of amphotericin B combined with fluconazole at different time points / 口腔疾病防治

Objective@#To investigate the in vitro interaction of amphotericin B (AmB) and fluconazole (FLC) at different time points and provide a reference for clinical combined treatment therapy of polyenes and azoles.@*Methods@#Candida albicans ATCC SC5314 was used in the study. The minimum inhibitory concentration (MIC) of antifungal drugs was determined using the double microdilution broth method. The same amount of DMSO and low concentration drugs were added to the DMSO treatment group at different time points (0, 2, 4, 6 h) to determine whether the solvent background environment affected the growth of Candida albicans. In the experimental group, to observe the effect of low concentration AmB on the antifungal effect of FLC, the experimental group was administered a low concentration of AmB (0.25 μg/mL or 0.125 μg/mL) added to FLC at different time points (0, 2, 4, 6 h), and the same amount of DMSO was added to FLC at different time points in the single drug control group. In the experimental group, to observe the effect of low concentration of FLC on the antifungal effect of AmB, the experimental group was administered a low concentration of FLC (0.06 μg/mL or 0.03 μg/mL) in AmB at different time points (0, 2, 4, 6 h), and the same amount of DMSO was used at different time points as the single drug control group. In the solvent group, the same amounts of DMSO and low concentration drugs were added at different time points. After resuscitation, the colony growth of each solvent control group, single-drug control group and experimental group was observed to evaluate the interaction between drug concentration and time. Compared with the AmB single-drug control group, there was no significant change in the experimental group with added low concentrations of FLC at 0 h (F=0.27, P=0.775), which was 1.74-1.93 times that of the control group at 2-4 h (P < 0.001), and there was no significant difference in colony count after 6 h (P > 0.05). @*Results@# Under the treatment of FLC at an inhibitory concentration (0.25 μg/ml), adding low concentration AMB did not affect the antifungal effect of FLC, and the multiple of colony count differences were not significant (P > 0.05).@*Conclusion@#The interaction between AmB and FLC was time-dependent. At the early stage (0 h), the interaction effect between fluconazole and amphotericin B was not clear. The fungicidal effect of AmB could be weakened when FLC was supplied at 2-4 h, and the effect of FLC on AmB was absent after 6 h.

Research progress on the relationship between Fusobacterium nucleatum and periodontitis / 口腔疾病防治

@#Periodontitis is an infectious disease caused by a variety of microorganisms. Fusobacterium nucleatum is closely related to periodontitis with a high detection rate. Fusobacterium nucleatum is able to coaggregate with other microorganisms and attach and invade epithelial cells with the help of adhesins. It can also promote the occurrence and development of periodontal diseases and even systemic diseases by destroying periodontal tissues with virulence factors and metabolites and inducing a host immune response. However, at present, drugs assisting periodontal nonsurgical treatment clinically cannot target specific periodontal pathogens, such as Fusobacterium nucleatum, which may lead to problems such as dysbacteriosis or drug resistance. Therefore, studies on the pathogenic mechanism of Fusobacterium nucleatum provide new ideas for the prevention and treatment of periodontitis. The idea is to develop materials, drugs, or probiotics that target adhesins, virulence factors, and metabolites or cut off each pathogenic pathway of Fusobacterium nucleatum to inhibit its proliferation and inflammatory responses in deep periodontal pockets and achieve a balance with other oral microorganisms, and the host is beneficial for the control of periodontitis.

Research progress on nano-calcium phosphate modified dental materials for the prevention and treatment of dental pulp diseases / 口腔疾病防治

@#Nanomaterials usually refer to tiny particles with a diameter of 1-100 nm, which often have unique physicochemical properties and are one of the main areas of research interest for development of dental biomaterials. Nano-calcium phosphate modified dental materials have been widely used in pit and fissure sealing, dental resin restoration, tooth adhesion, and root canal sealing. The current research shows that the dental material modified by nano-calcium phosphate has stronger mechanical properties and shows long-term calcium and phosphorus ion release and excellent ion recharging ability, which can promote the remineralization of tooth hard tissue and has good prospects for application. However, it is difficult to accurately simulate the complex environment of the oral cavity. Therefore, the biocompatibility, cytotoxicity and effect of clinical application of nano-calcium phosphate modified dental materials still needs further study. This review summarizes and discusses the recent research progress regarding nano-calcium phosphate modified dental materials in the prevention and treatment of dental pulp diseases.

The relationship between Candida albicans infection and oral cancer / 口腔疾病防治

@#Oral cancer is one of the most common cancers that occur in the head and neck and can seriously affect the life span and living standard of oral cancer patients. Candida albicans （C. albicans） is the most common opportunistic pathogenic fungus in the oral cavity, shows pathogenicity and easily causes Candida infection when the host′s immune function is low. Recent studies have shown that C. albicans infection is closely related to oral cancer. This paper reviews the epidemiology of C. albicans infection in oral cancer patients, the influence of C. albicans infection on the occurrence and development of oral cancer and research on its mechanism. Existing studies have shown an increased risk of C. albicans infection in oral cancer patients, while C. albicans infection may promote the occurrence and development of oral cancer through mechanisms such as damaging the oral epithelium; producing carcinogens, including nitrosamine and acetaldehyde; and inducing a chronic inflammatory response and T helper cell 17 immune response. However, these mechanisms are still relatively superficial and lack sufficient direct evidence. In the future, additional in-depth studies are still needed to further clarify the cancer-promoting mechanisms of C. albicans and provide new ideas for the prevention and treatment of oral cancer.

Research progress on the relationship between Candida albicans and oral potentially malignant disorders / 口腔疾病防治

@#Oral potentially malignant disorders (OPMDs) refer to all epithelial lesions and conditions with an increased risk for malignant transformation, including oral leukoplakia, oral submucous fibrosis, oral lichen planus, erythroplakia, etc. Additionaly, oral infection of Candida albicans is considered to be closely related to the development of OPMDs. It was demonstrated in previous studies that the detection rate of Candida albicans was higher in the oral mucosa with OPMDs; in addition, Candida albicans showed high virulence by adhering to and destroying the epithelium. Moreover, Candida albicans was able to induce the immune response and cause chronic inflammation in the epithelium, producing carcinogenic products such as acetaldehyde. The factors mentioned above play a key role in the occurrence and development of OPMDs. Furthermore, the oral mucosa is highly susceptible to Candida albicans. The present review provides an introduction to the relationship between Candida albicans and OPMDs.

Advances in Treponema denticola and oral diseases / 口腔疾病防治

@#Treponema denticola is an important pathogenic Treponema pathogen in the human oral cavity. Early studies have found that Treponema denticola is closely related to the occurrence and development of periodontal diseases. With the development of technical methods in recent years, many studies have shown that Treponema denticola not only can participate in periodontal diseases through a variety of mechanisms but also can play an important role in the development of various oral diseases. Treponema denticola is detected in high concentrations in peri-apical diseases and peri-implant diseases, and its surface protein is also prevalent in oral tumor samples. This paper reviews the research progress of Treponema denticola in periodontal diseases, pulp peri-apical diseases, peri-implant diseases and oral tumors, and summarizes the relevant mechanisms. For example, Treponema denticola can cause immune regulation disorder, destroy the epithelial barrier, induce bone absorption, promote the occurrence and development of inflammation through a variety of surface proteins, including chymotrypsin-like protease complex (CTLP), major outer sheath protein (Mosp), Td92, and LOS. It can also escape complement-mediated killing effects through surface FhbB lipoproteins and promote the occurrence and development of oral tumors by regulating the tumor microenvironment. These theories provide a theoretical basis for further understanding the development of oral diseases, controlling the infection of Treponema denticola, and exploring more effective treatment strategies.

Research progress on factors affecting bacterial adhesion on the oral implant surface / 口腔疾病防治

@#Reducing the adhesion of microorganisms and the formation of biofilms on implant surfaces can prevent peri-implant inflammation and optimize the long-term prognosis of implanted dentures. To provide theoretical support for the development of new materials or the modification of existing materials and the improvement of the success rate of implant repair, a literature review was conducted, which shows that the factors influencing bacterial adhesion on dental implant surfaces included the type of implant material, material roughness, nonspecific physical and chemical properties, the type of antibacterial coating, the components of the acquired membrane on the implant surface, the structure of the bacterial cell wall, etc. The current research direction of implant materials aims to reduce bacterial adhesion and promote bone bonding. However, there is no consensus on the physical and chemical properties of implants that meet this requirement. At present, the development trend in implant materials is guided by research of the “core microbiome” of peri-implant inflammation, based on study of the factors related to the adhesion of pathogenic microorganisms to the implant surface, which is organically combined with a variety of modification methods to change the surface-related properties of the implant materials and even to endow the implant with antibacterial properties to reduce or inhibit the adhesion of pathogenic bacteria to the implant.

Association between PTCH1 gene polymorphisms and chronic obstructive pulmonary disease susceptibility in a Chinese Han population: a case-control study / 中华医学杂志(英文版)

BACKGROUND@#Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Genome-wide association studies in non-Asian population revealed a link between COPD and mutations in the PTCH1 gene encoding Patched1, a receptor in the Hedgehog signaling pathway important for lung morphogenesis and pulmonary function. The aim of this study was to investigate the association between PTCH1 polymorphisms and the COPD risk in the Chinese Han population.@*METHODS@#We performed a case-control study including 296 patients with COPD and 300 healthy individuals. Single-nucleotide polymorphisms in the PTCH1 gene were identified and genotyped based on the linkage disequilibrium analysis in all participants. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated using logistic regression analysis after adjustment for age, gender, and smoking.@*RESULTS@#In total, 28 single-nucleotide polymorphisms were identified in patients with COPD. Among them, "A" allele of rs28491365 (OR: 1.388, 95% CI: 1.055-1.827, P = 0.018), and "G" alleles of rs10512248 (OR: 1.299, 95% CI: 1.021-1.653, P = 0.033) and rs28705285 (OR: 1.359, 95% CI: 1.024-1.803, P = 0.033; respectively) were significantly associated with an increased COPD risk. Genetic model analysis revealed that the "T/T" genotype of rs34695652 was associated with a decreased COPD risk under the recessive model (OR: 0.490, 95% CI: 0.270-0.880, P = 0.010), whereas rs28504650/rs10512248 haplotype CG was significantly associated with an increased COPD risk after adjustment for age, gender, and smoking status (OR: 6.364, 95% CI: 1.220-33.292, P = 0.028).@*CONCLUSIONS@#The study provides a new insight into the role of PTCH1 polymorphisms in the susceptibility to COPD in the Chinese Han population.

Research progress on the effect of pH-sensitive drug delivery systems on oral microorganisms / 口腔疾病防治

@#Microorganisms are closely related to the occurrence and development of common oral diseases. Due to the unique physiological and anatomical characteristics of the oral cavity, locally introduced antibacterial drugs cannot be maintained in the effective concentration range under the effect of saliva erosion. Therefore, to enhance the retention and bioavailability of antibacterial drugs in biofilms, some scholars designed pH sensitive drug delivery systems with the fact that the pH value of oral biofilm is lower than the physiological pH value. This article reviews the research reports of a pH-sensitive drug delivery system in the oral cavity and elaborates its application in oral diseases such as dental caries, endodontic disease, periapical disease, peri-implant diseases, and oral candidiasis. Literature review Results show that the pH-sensitive drug delivery system loaded with antibacterial drugs could be used for the control of oral microorganisms with excellent pH sensitivity and antibacterial properties, especially in the application of acid-producing bacteria such as Streptococcus mutans for the prevention and treatment of dental caries. However, the research of pH-sensitive drug delivery systems in the oral cavity is still limited to basic research,and in clinical applications, it still faces many challenges, such as a complex design and synthesis, difficulties with lasting effects and eliminating drug-resistance and persistent bacteria. Further optimization of pH sensitive systems, as well as animal experiments and in vivo studies will be the focus of future research.

Factors influencing the structure of the oral microbiome / 口腔疾病防治

@#The oral microbiome has been identified as one of the most diverse microbial communities in the human body, and the ecological imbalance of the oral microbiome can not only induce a variety of oral diseases, such as dental caries, pulpitis, apical periodontitis, and periodontal diseases, but also is closely related to cardiovascular diseases, diabetes and other systemic diseases. The structure of the oral microbiome is affected by multiple factors. This paper reviews and summarizes the effects of genetics, the environment, diet and systemic diseases. Literature reviews have shown that environmental factors play an important role in the structure of the oral microbiome, while the influence of genetic and dietary factors is still controversial. In addition, systemic diseases may also affect the oral microbial community. High-throughput sequencing studies have identified some “core microbiota”, and “core microbiota” in different environments and in different genetic backgrounds will be the next research direction.

A morphological classification for vocal fold leukoplakia / Classificação morfológica das leucoplasias de prega vocal

Abstract Introduction: There is still no general method for discriminating between benign and malignant leukoplakia and identifying vocal fold leukoplakia. Objective: To evaluate the reliability of a morphological classification and the correlation between morphological types and pathological grades of vocal fold leukoplakia. Methods: A total of 375 patients with vocal fold leukoplakia between 2009 and 2015 were retrospectively reviewed. Two observers divided the vocal fold leukoplakia into flat and smooth, elevated and smooth, and rough type on the basis of morphological appearance. The inter-observer reliability was evaluated and the results of classification from both observers were compared with final pathological grades. Clinical characteristics between low risk and high risk group were also analyzed. Results: The percentage inter-observer agreement of the morphological classification was 78.7% (κ = 0.615, p < 0.001). In the results from both observers, the morphological types were significantly correlated with the pathological grades (p1 < 0.001, p2 < 0.001, Kruskal-Wallis test; r1 = 0.646, p1 < 0.001, r2 = 0.539, p2 < 0.001, Spearman Correlation Analysis). Multivariate analysis showed patient's age (p = 0.018), the size of lesion (p < 0.001), and morphological type (p < 0.001) were significantly different between low risk group and high risk group. Combined receiver operating characteristic curve analysis of significant parameters revealed an area under the receiver operating characteristic curve of 0.863 (95% CI 0.823-0.903, p < 0.001). Conclusions: The proposed morphological classification of vocal fold leukoplakia was consistent between observers and morphological types correlated with pathological grades. Patient's age, the size of lesion, and morphological type might enable risk stratification and provide treatment guidelines for vocal fold leukoplakia.

Resumo Introdução: Ainda não há um método universal estabelecido para diferenciar entre a leucoplasia benigna e maligna ou identificar as leucoplasias das pregas vocais. Objetivo: Avaliar a confiabilidade de uma classificação morfológica e a correlação entre os tipos morfológicos e os graus histopatológicos das leucoplasias de pregas vocais. Método: Os registros de 375 pacientes com leucoplasia da prega vocal assistidos entre 2009 e 2015 foram revisados retrospectivamente. Dois observadores dividiram a leucoplasia da prega vocal entre tipo plano e liso, elevado e liso, e rugoso, com base na aparência morfológica. A confiabilidade interobservador foi avaliada e os resultados de classificação de ambos os observadores foram comparados com os graus histopatológicos finais. As características clínicas entre os grupos de baixo risco e alto risco também foram analisadas. Resultados: A porcentagem da concordância interobservador da classificação morfológica foi de 78,7% (κ = 0,615, p < 0,001). Nos resultados de ambos os observadores, os tipos morfológicos correlacionaram-se significativamente com os graus histopatológicos (p1 < 0,001, p2 < 0,001, teste de Kruskal-Wallis; r1 = 0,646, p1 < 0,001, r2 = 0,539, p2 < 0,001, análise de correlação de Spearman). A análise multivariada mostrou que a idade do paciente (p = 0,018), o tamanho da lesão (p < 0,001) e o tipo morfológico (p < 0,001) foram significativamente diferentes entre o grupo de baixo risco e o de alto risco. A análise da curva ROC (Receiver Operating Characteristic) combinada de parâmetros significativos revelou uma área sob a curva de 0,863 (IC 95%: 0,823 ± 0,903, p < 0,001). Conclusões: A classificação morfológica proposta para leucoplasia de prega vocal foi consistente entre observadores e os tipos morfológicos correlacionaram-se com os graus histopatológicos. A idade do paciente, o tamanho da lesão e o tipo morfológico podem permitir a estratificação de risco e fornecem diretrizes de tratamento para a leucoplasia da prega vocal.

Enzymatic preparation of fructooligosaccharides-rich burdock syrup with enhanced antioxidative properties

Background: Burdock (Arctium lappa L.) is a fructan-rich plant with prebiotic potential. The aim of this study was to develop an efficient enzymatic route to prepare fructooligosaccharides (FOS)-rich and highly antioxidative syrup using burdock root as a raw material. Results: Endo-inulinase significantly improved the yield of FOS 2.4-fold while tannase pretreatment further increased the yield of FOS 2.8-fold. Other enzymes, including endo-polygalacturonase, endo-glucanase and endo-xylanase, were able to increase the yield of total soluble sugar by 11.1% (w/w). By this process, a new enzymatic process for burdock syrup was developed and the yield of burdock syrup increased by 25% (w/w), whereas with FOS, total soluble sugars, total soluble protein and total soluble polyphenols were enhanced to 28.8%, 53.3%, 8.9% and 3.3% (w/w), respectively. Additionally, the scavenging abilities of DPPH and hydroxyl radicals, and total antioxidant capacity of the syrup were increased by 23.7%, 51.8% and 35.4%, respectively. Conclusions: Our results could be applied to the development of efficient extraction of valuable products from agricultural materials using enzyme-mediated methods.

Research progress on the function and metabolism of d-alanine in bacteria / 口腔疾病防治

@#D-alanine is a chiral molecule of L-alanine that participates in the formation and regulation of cell wall peptidoglycans, phosphoteichoic acid, spore germination and respiratory metabolism in individual bacteria. D-alanine participates in the formation and regulation of biofilm in bacterial communities. The function and metabolism of D-alanine in bacteria are specific, and the enzymes and genes in its metabolic pathway can be used as drug targeting sites. In this paper, the synthesis, metabolism and function of D-alanine in bacteria were reviewed, and the relationship between D-alanine and pathogenicity of Streptococcus mutans was discussed to provide a theoretical basis for candidate targeting sites of anti-caries drugs. According to existing research results, the enzymes and related genes involved in D-alanine metabolism play important roles in the growth and biofilm formation of Streptococcus mutans, and D-alanine is expected to be a target for the design of anti-caries drugs.

Research progress on the mechanism of radiocaries formation / 口腔疾病防治

@#Radioactive caries is the most common complication of head and neck cancer after radiotherapy. It is a rapidly progressing and widespread destructive disease of tooth tissue after radiotherapy. It is currently believed that salivary gland dysfunction and direct damage to teeth by radiation are the main pathogenic factors of radiation caries. In this paper, the pathogenesis of radiation caries, especially the effect of radiotherapy on oral caries-related microorganisms, are reviewed, and future research directions are proposed. Existing research has revealed that the structures of oral microorganisms change significantly after radiotherapy. The number and proportion of some dental caries-related microorganisms such as Streptococcus mutans, Lactobacillus lactis and Candida albicans increased, and their virulence increased. This indicated that the changes in oral microorganisms caused by radiotherapy played an important role in radioactive caries.

Progress in researches on latent class analysis based subtyping of depression / 上海交通大学学报（医学版）

Depression is a highly heterogeneous syndrome. Homogeneous subtypes according to symptomatology of illness may contribute to development of individualized treatment, assessment on outcomes and prognosis. Latent class analysis is a flexible statistical approach to determine classes with similar symptom profiles in a heterogeneous group, which has been widely used in data-driven subtyping of depression to increase accuracy of subtyping. This article reviewed existing symptom-based subtypes of depression and findings of researches on latent class analysis based illness subtyping.