• The Korean Journal of Cytopathology
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• v.18 no.2
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• pp.165-169
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• 2007

The authors present the fine needle aspiration cytology (FNAC) cytologic findings of a case of extranodal marginal zone B cell lymphoma (MZBCL), which featured abundant plasma cells and eosinophilic histiocytes arising in both parotid glands. A 49-year-old female presented with palpable masses in both parotid glands. She had been suffering from systemic lupus erythematosus and rheumatoid arthritis. The lesions were evaluated by FNAC and smears showed a small number of clusters of oncocytic cells with abundant eosinophilic granular cytoplasm and small nuclei, intermixed with small to medium-sized lymphoid cells containing round to lobulated nuclei, which suggested Warthin's tumor. Some of lymphoid cells had a plasmacytoid appearance, and some scattered large cells contained a large amount of eosinophilic cytoplasm. Bilateral superficial parotidectomy was performed and a histopathologic study indicated MZBCL with abundant plasma cells, intermixed with eosinophilic histiocytes. The presence of oncocytic cells and a mixture of lymphoid and plasma cells indicates Warthin's tumor, but the cytologic features of a relatively monotonous small to medium-sized lymphoid infiltrate suggest the possibility of MZBCL in the clinical setting of an FNAC study performed on a patient suffering from a connective tissue disease.

• Biomolecules & Therapeutics
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• v.25 no.2
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• pp.130-139
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• 2017

$CXCR5^+$ T follicular helper (Tfh) cells are associated with aberrant autoantibody production in patients with antibody-mediated autoimmune diseases including lupus. Follicular regulatory T (Tfr) cells expressing CXCR5 and Bcl6 have been recently identified as a specialized subset of $Foxp3^+$ regulatory T (Treg) cells that control germinal center reactions. In this study, we show that retroviral transduction of CXCR5 gene in $Foxp3^+$ Treg cells induced a stable expression of functional CXCR5 on their surface. The Cxcr5-transduced Treg cells maintained the expression of Treg cell signature genes and the suppressive activity. The expression of CXCR5 as well as Foxp3 in the transduced Treg cells appeared to be stable in vivo in an adoptive transfer experiment. Moreover, Cxcr5-transduced Treg cells preferentially migrated toward the CXCL13 gradient, leading to an effective suppression of antibody production from B cells stimulated with Tfh cells. Therefore, our results demonstrate that enforced expression of CXCR5 onto Treg cells efficiently induces Tfr cell-like properties, which might be a promising cellular therapeutic approach for the treatment of antibody-mediated autoimmune diseases.

• Tuberculosis and Respiratory Diseases
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• v.82 no.4
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• pp.285-297
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• 2019

Connective tissue disease (CTD) is a collection of disorders characterized by various signs and symptoms such as circulation of autoantibodies in the entire system causing damage to internal organs. Interstitial lung disease (ILD) which is associated with CTD is referred to as CTD-ILD. Patients diagnosed with ILD should be thoroughly examined for the cooccurrence of CTD, since the treatment procedures and prognosis of CTD-ILD are vary from those of idiopathic interstitial pneumonia. The representative types of CTD which may accompany ILD include rheumatoid arthritis, systemic sclerosis (SSc), Sjogren's syndrome, mixed CTD, idiopathic inflammatory myopathies, and systemic lupus erythematous. Of these, ILD most frequently co-exists with SSc. If an ILD is observed in the chest, high resolution computed tomography and specific diagnostic criteria for any type of CTD are met, then a diagnosis of CTD-ILD is made. It is challenging to conduct a properly designed randomized study on CTD-ILD, due to low incidence. Therefore, CTD-ILD treatment approach is yet to been established in absence of randomized controlled clinical trials, with the exception of SSc-ILD. When a patient is presented with acute CTD-ILD or if symptoms occur due to progression of the disease, steroid and immunosuppressive therapy are generally considered.

• Clinical and Experimental Pediatrics
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• v.51 no.11
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• pp.1217-1221
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• 2008

Purpose : An association between idiopathic thrombocytopenic purpura (ITP) and systemic lupus erythematosus (SLE) has been recognized for decades because thrombocytopenia is the first manifestation in some patients with SLE. However, the risk of later development of SLE in childhood ITP is currently unknown. We retrospectively evaluated the incidence and clinical significance of the positive antinuclear antibody (ANA) in children with acute ITP. Methods : This study was retrospectively performed to review the clinical and laboratory characteristics in 77 children diagnosed to have acute ITP and admitted to the Pusan National University Hospital between January 2003 and December 2006. Patients tested positive for ANA were regularly followed-up for at least 12 months for symptoms indicative of SLE. Results : Seventy-seven children were included in the study; 38 males (49.4%) and 39 females (50.5%), the mean age was 4.5 years. Sixteen (20.8%) ITP patients had a positive ANA, with a median titer of 1:320. The mean age of the patients with positive ANA was 9.3 years, which is much older than 3.3 years for patients with negative ANA (P<0.05). The positive ANA group was predominantly female (81.3%) compared to the negative ANA group (P<0.05). There was no statistically significant difference in mean platelet counts between both groups. No statistically significant difference was found in ANA positivity and progression to chronic ITP or SLE. After the median follow-up of 32 months, SLE was diagnosed only in one ITP patient with positive ANA. Conclusion : Our data demonstrated that ANA positivity is often found in children with acute ITP. Large-scale studies should be considered to determine the significance of ANA positivity in childhood ITP for the later development of SLE.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.1
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• pp.153-157
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• 2014

Purpose: SLE (systemic lupus erythematosus) is an inflammatory autoimmune disease, characterized by various autoantibody. The detection of Anti double-stranded DNA (Anti-ds DNA) is important in the diagnostics of SLE, and include the American College of Rheumatology (ACR) diagnostic criteria for SLE. Also SLE disease activity and correlativity with the level Anti-ds DNA antibody have been reported and Anti-ds DNA antibody quantitative test is very useful for tracing before and after SLE treatment. When These Anti-ds DNA antibody test (Farr assay: $^{125}I$ labeled ds-DNA and bound Anti-ds DNA antibodies complex in serum is precipitated by ammonium sulfate and used to centrifugation, measured it) inhaled supernatant after centrifugation, a lipemic specimen does not facilitate the formation of precipitate and also occurs situation was inhaled with precipitate. To solve these problems, The Influence of the degree of lipemic specimen was evaluated. Materials and Methods: September 2012 to February 2013, We selected lipemic samples (n=81) of specimen commissioned by Anti-ds DNA antibody test. Lipemic samples were done pre-treatment (high-speed centrifugation: 14,000 rpm 5 mins) used a micro-centrifuge (Eppendorf Model 5415D). At the same time lipemic specimen and pre-treatment samples were performed Anti-ds DNA antibody test (Anti-ds DNA kit, Trinity Biotech, Ireland). Statistical analysis were analyzed Pearson's correlation coefficients and regression and paired t-test, and Difference (%). Results: Experimental group 1 (Lipemic Specimen Anti-ds DNA Ab concentration ${\leq}7IU/mL$) at y=0.368X+4.732, $R^2=0.023$, Pearson's correlation coefficient was 0.154, paired t-test (P=0.003), Difference (%) mean 65.7 and showed a statistically significant difference. Experimental group 2 (Lipemic Specimen Anti-ds DNA Ab concentration ${\geq}8IU/mL$) at y=0.983X+0.298, $R^2=0.994$, Pearson's correlation coefficient showed 0.997, paired t-test (P=0.181), Difference (%) mean -5.53 made no statistically significant difference. Conclusion: Lipemic sample of low Anti-ds DNA Ab concentration (2.5-7 IU/mL) and the result is obtained pre-treatment (high-speed centrifugation: 14,000 rpm 5 mins) were made a significant difference statistically. Anti-ds DNA is one of the primary auto-antibodies present in patients with SLE, and remain an important diagnostic test for SLE. Therefore, we recommend preprocessing (high-speed centrifugation: 14,000 rpm 5 mins) in order to exclude the influence of lipemic specimen.

• Journal of Animal Science and Technology
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• v.53 no.4
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• pp.303-310
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• 2011

Phylogenetic relationships of Jeju dogs to other domestic and foreign dog breeds were assessed using mtDNA D-loop sequences. Neighbor-joining trees were constructed using complete sequences (970 bp excluding the tandem repeat region) determined for five Cheju, four Jindo, four Sapsaree, five Pungsan, two of each East and West Laika dogs (Canis familiaris), two gray wolves (Canis lupus) and two coyotes (Canis latrans) and also published complete sequences for dogs. Coyote sequences were used as outgroups. In addition, a total of 214 haplotypes of 598bp D-loop sequences from 30 dog breeds were collected from GenBank and used to investigate genetic structure of population. In the analyses of full D-loop sequence variation and the phylogenetic trees constructed by neighbor-joining method, neither haplotypes nor clades specific for any domestic dog breeds were observed. The inter-species sequence variation (4.51%) between domestic dogs and wolves was much higher than the intra-species sequence variation within domestic dogs (1.63%) and wolves (3.64%). The divergence of the dog and wolf occurred approximately 1~2 million years ago based on these values. The taxa of Jeju dog breed in the phylogenetic tree are clustered separately and intermingled with other taxa of breeds, suggesting that active crossbreeding of Jeju dogs with other domestic breeds.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.38-45
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• 2005

Purpose : The purpose of this study was to analyze the therapeutic effect of plasmapheresis in various pediatric diseases. Methods : Therapeutic plasmapheresis was performed by COBE Spectra centrifugation. Nine cases were included in this study. The number an[;. method of plasmapheresis, together with the progress and prognosis of each case were retrospectively reviewed. Results : The patients' ages ranged from 26 mont]Is to 16 years of age, and the mean age was 9.9 years. There were S males and 4 females. The underlying diseases requiring plasmapheresis included 2 cases of hemolytic uremic svndrome(HUS), 1 case of lupus nephritis, 2 cases of rapidly Progressive glomerulonephritis(RPGN), 1 case of focal segmental glomorulosclerosis(FSGS), 1 case of systemic vasculitis after pulmonary hemorrhage, 1 case of acute renal failure associated with pulmonary hemoIThage, and 1 case of acute rejection after renal transplantation. The average number of plasmapheresis performed was 6.2 times with a range of 3 to 13 times. The patients with HUS, lupus nephritis, ANCA positive systemic vasculitis induced by pulmonary hemorrhage and ARF-associated pulmonary hemorrhage showed a good response to therapeutic plasmapheresis, but the patients with RPGN, refractory FSGS, and acute rejection after renal transplantation were not responsive to treatment. The most common side effect was hypocalcemia which was rarely symptomatic. Vital signs were not compromised. Conclusion : Although it is presumptuous to generalize the therapeutic effects of plasma pheresis in different diseases due to the small number of study subjects, this study shows that plasmapheresis may be an effective therapeutic modality in various pediatrics diseases and should be considered as a therapeutic option.

• Childhood Kidney Diseases
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• v.5 no.2
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• pp.78-86
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• 2001

Purpose: Rapidly progressive glomerulonephritis (RPGN) is characterized by the rapid increase in serum creatitnin and crescents formation involving more than $50\%$ of glomeruli. 10 patients who had been treated for RPGN were studied retrospectively for thier underlying diseases and clinical features Method: Cilinical review was performed on 10 children who were diagnosed with RPGN by clinical features and renal biopsy and followed up at department of pediatrics during tile last 10 years, from May 1990 to May 2000. Result: There were 6 males and 4 females between the ages of 2.1 and 14.3 years (mean $10.9{\pm}3.8$). 3 had Henoch-$Sch{\ddot{o}}nlein$ purpura nephritis; 2, idiopathic rapidly progressive glomerulonephritis; 2, lupus nephritis; 1, hemolytic uremic syndrome; 1, membranous glomerulonephritis and 1, microscopic polyangiitis. The most common chief complaints were gross hematuria and oliguria. Initial clinical features included proteinuria, edema, hypertension, nausea and arthralgia. Mean serum BUN was $74.2{\pm}39.1\;mg/dL$ mean serum creatinin, $3.2{\pm}1.8\;mg/dL$ and mean creatinin clearance, $26.5{\pm}13.2\;mL/min/1.73m^2$. Antineutrophil cytoplasmic antibody was positive only in microscopic polyangiitis. ANA and Anti-DNA antibody were positive in two lupus nephritis patients. Serum complements were decreased in 4 patients. All patients except Hemolytic uremic syndrome received steroid pulse therapy and immunosupressive agents. 3 patients were performed acute peritoneal dialysis and 2 patients were given plasmapheresis. At the last follow up, 1 patient was dead, 4 patients had elevated serum creatinin, 2 of these 4 patients were on chronic ambulatory peritoneal dialysis and 6 patients had normal renal function. Conclusion: Rapidly progressive glomerulonephritis is a medical emergency that requires very rapid diagnosis, classification, and therapy. Appropriate therapy selected on the basis of underlying disease mechanism can substantially improve renal survival. (J. Korean Soc Pediatr Nephrol 2001 ; 5 : 78-86)

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.15 no.2
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• pp.271-288
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• 2002

Authors investigated the pathogenesis and treatment of dennatosurgical diseases in the ImJeungJiNamUiAn(臨證指南醫案). 1. The symptoms and diseases of dermatosurgery were as follows; 1) BanSaJinRa(반사진라) : eczema, atopic dermatitis, seborrheic dermatitis, psoriasis, lichen planus, pityriasis rosea, hives, dermographism, angioedema, cholinergic urticaria, urticaria pigmentosa, acne, milium, syringoma, keratosis pilaris, discoid lupus erythematosus, hypersensitivity vasculitis, drug eruption, polymorphic light eruption, rheumatic fever, juvenile rheumatoid arthritis(Still's disease), acute febrile neutrophilic dermatosis(Sweet's syndrome), Paget's disease, folliculitis, viral exanthems, molluscum contagiosum, tinea, tinea versicolor, lymphoma, lymphadenitis, lymphangitis, granuloma annulare, cherry angioma 2) ChangYang(瘡瘍) : acute stage eczema, seborrheic dermatitis, stasis ulcer, intertrigo, xerosis, psoriasis, lichen planus, ichthyosis, pityriasis rosea, rosacea, acne, keratosis pilaris, dyshidrosis, dermatitis herpetiformis, herpes gestationis, bullae in diabetics, pemphigus, lupus erythematosus, fixed drug eruption, erythema multiforme, toxic epidermal necrolysis, toxic shock syndrome, staphylococcal scaled skin syndrome, scarlet fever, folliculitis, impetigo, pyoderma gangrenosum, tinea, candidiasis, scabies, herpes simplex, herpes zoster, chicken pox, Kawasaki syndrome, lipoma, goiter, thyroid nodule, thyroiditis, hyperthyroidism, thyroid cancer, benign breast disorder, breast carcinoma, hepatic abscess, appendicitis, hemorrhoid 3) Yeok(疫) : scarlet fever, chicken pox, measles, rubella, exanthem subitum, erythema infectiosum, Epstein-Barr virus infection, cytomegalovirus infection, hand-foot-mouth disease, Kawasaki disease 4) Han(汗) : hyperhidrosis 2. The pathogenesis and treatment of dermatosurgery were as follows; 1) When the pathogenesis of BalSa(발사), BalJin(發疹), BalLa(발라) and HangJong(項腫) are wind-warm(風溫), exogenous cold with endogenous heat(外寒內熱), wind-damp(風濕), the treatment of evaporation(解表) with Menthae Herba(薄荷), Arctii Fructus(牛蒡子), Forsythiae Fructus(連翹) Mori Cortex(桑白皮), Fritillariae Cirrhosae Bulbus(貝母), Armeniaoae Amarum Semen(杏仁), Ephedrae Herba(麻黃), Cinnamomi Ramulus(桂枝), Curcumae Longae Rhizoma(薑黃), etc can be applied. 2) When the pathogenesis of BuYang(부양), ChangI(瘡痍) and ChangJilGaeSeon(瘡疾疥癬) are wind-heat(風熱), blood fever with wind transformation(血熱風動), wind-damp(風濕), the treatment of wind-dispelling(疏風) with Arctii Fructus(牛蒡子), Schizonepetae Herba(荊芥), Ledebouriellae Radix(防風), Dictamni Radicis Cortex(白鮮皮), Bombyx Batrytioatus(白？?), etc can be applied. 3) When the pathogenesis of SaHuHaeSu(사후해수), SaJin(사진), BalJin(發疹), EunJin(은진) and BuYang(부양) are wind-heat(風熱), exogenous cold with endogenous heat(外寒內熱), exogenous warm pathogen with endogenous damp-heat(溫邪外感 濕熱內蘊), warm pathogen's penetration(溫邪內陷), insidious heat's penetration of pericardium(伏熱入包絡), the treatment of Ki-cooling(淸氣) with TongSeongHwan(通聖丸), Praeparatum(豆？), Phyllostachys Folium(竹葉), Mori Cortex(桑白皮), Tetrapanacis Medulla(通草), etc can be applied. 4) When the pathogenesis of JeokBan(적반), BalLa(발라), GuChang(久瘡), GyeolHaek(結核), DamHaek(痰核), Yeong(？), YuJu(流注), Breast Diseases(乳房疾患) and DoHan(盜汗) are stagnancy's injury of Ki and blood(鬱傷氣血), gallbladder fire with stomach damp(膽火胃濕), deficiency of Yin in stomach with Kwolum's check (胃陰虛 厥陰乘), heat's penetration of blood collaterals with disharmony of liver and stomach(熱入血絡 肝胃不和), insidious pathogen in Kwolum(邪伏厥陰), the treatment of mediation(和解) with Prunellae Spica(夏枯草), Chrysanthemi Flos(菊花), Mori Folium (桑葉), Bupleuri Radix(柴胡), Coptidis Rhizoma(黃連), Scutellariae Radix(黃芩), Gardeniae Fructus(梔子), Cyperi Rhizoma(香附子), Toosendan Fructus(川？子), Curcumae Radix(鬱金), Moutan Cortex(牧丹皮), Paeoniae Radix Rubra(赤芍藥), Unoariae Ramulus Et Uncus(釣鉤藤), Cinnamorni Ramulus(桂枝), Paeoniae Radix Alba(白芍藥), Polygoni Multiflori Radix (何首烏), Cannabis Fructus (胡麻子), Ostreae Concha(牡蠣), Zizyphi Spinosae Semen(酸棗仁), Pinelliae Rhizoma(半夏), Poria(백복령). etc can be applied. 5) When the pathogenesis of BanJin(반진), BalLa(발라), ChangI(瘡痍), NamgChang(膿瘡). ChangJilGaeSeon(瘡疾疥癬), ChangYang(瘡瘍), SeoYang(署瘍), NongYang(膿瘍) and GweYang(潰瘍) are wind-damp(風濕), summer heat-damp(暑濕), damp-warm(濕溫), downward flow of damp-heat(濕熱下垂), damp-heat with phlegm transformation(濕熱化痰), gallbladder fire with stomach damp(膽火胃濕), overdose of cold herbs(寒凉之樂 過服), the treatment of damp-resolving(化濕) with Pinelliae Rhizoma(半夏), armeniacae Amarum Semen(杏仁), Arecae Pericarpium(大腹皮), Poria(백복령), Coicis Semen(薏苡仁), Talcum(滑石), Glauberitum(寒水石), Dioscoreae Tokoro Rhizoma(？？), Alismatis Rhizoma(澤瀉), Phellodendri Cortex(黃柏), Phaseoli Radiati Semen(？豆皮), Bombycis Excrementum(?沙), Bombyx Batryticatus(白？?), Stephaniae Tetrandrae Radix(防己), etc can be applied. 6) When the pathogenesis of ChangPo(瘡泡), hepatic abscess(肝癰) and appendicitis(腸癰) are food poisoning(食物中毒), Ki obstruction & blood stasis in the interior(기비혈어재과), damp-heat stagnation with six Bu organs suspension(濕熱結聚 六腑不通), the treatment of purgation(通下) with DaeHwangMokDanPiTang(大黃牧丹皮湯), Manitis Squama(穿山甲), Curcumae Radix(鬱金), Curcumae Longae Rhizoma(薑黃), Tetrapanacis Medulla(通草), etc can be applied. 7) When the pathogenesis of JeokBan(적반), BanJin(반진), EunJin(은진). BuYang(부양), ChangI(瘡痍), ChangPo(瘡泡), GuChang(久瘡), NongYang(膿瘍), GweYang(潰瘍), Jeong(정), Jeol(癤), YeokRyeo(疫？) and YeokRyeolpDan(疫？入？) are wind-heat stagnation(風熱久未解), blood fever in Yangmyong(陽明血熱), blood fever with transformation(血熱風動), heat's penetration of blood collaterals(熱入血絡). fever in blood(血分有熱), insidious heat in triple energizer(三焦伏熱), pathogen's penetration of pericardium(心包受邪), deficiency of Yong(營虛), epidemic pathogen(感受穢濁), the treatment of Yong & blood-cooling(淸營凉血) with SeoGakJiHwangTang(犀角地黃湯), Scrophulariae Radix(玄參), Salviae Miltiorrhizae Radix(丹參), Angelicae Gigantis Radix(當歸), Polygoni Multiflori Radix(何首烏), Cannabis Fructus(胡麻子), Biotae Semen(柏子仁), Liriopis Tuber(麥門冬), Phaseoli Semen(赤豆皮), Forsythiae Fructus(連翹), SaJin(사진), YangDok(瘍毒) and YeokRyeoIpDan(역려입단) are insidious heat's penetration of pericardium(伏熱入包絡), damp-warm's penetration of blood collaterals(濕溫入血絡), epidemic pathogen's penetration of pericardium(심포감수역려), the treatment of resuscitation(開竅) with JiBoDan(至寶丹), UHwangHwan(牛黃丸), Forsythiae Fructus(連翹), Curcumae Radix(鬱金), Tetrapanacis Medulla(通草), Acori Graminei Rhizoma(石菖蒲), etc can be applied. 9) When the pathogenesis of SaHuSinTong(사후신통), SaHuYeolBuJi(사후열부지), ChangI(瘡痍), YangSon(瘍損) and DoHan(盜汗) are deficiency of Yin in Yangmyong stomach(陽明胃陰虛), deficiency of Yin(陰虛), the treatment of Yin-replenishing(滋陰) with MaekMunDongTang(麥門冬湯), GyeongOkGo(瓊玉膏), Schizandrae Fructus(五味子), Adenophorae Radix(沙參), Lycii Radicis Cortex (地骨皮), Polygonati Odorati Rhizoma(玉竹), Dindrobii Herba(石斛), Paeoniae Radix Alba(白芍藥), Ligustri Lucidi Fructus (女貞子), etc can be applied. 10) When the pathogenesis of RuYang(漏瘍) is endogenous wind in Yang collaterals(陽絡內風), the treatment of endogenous wind-calming(息風) with Mume Fructus(烏梅), Paeoniae Radix Alba (白芍藥), etc be applied. 11) When the pathogenesis of GuChang(久瘡), GweYang(潰瘍), RuYang(漏瘍), ChiChang(痔瘡), JaHan(自汗) and OSimHan(五心汗) are consumption of stomach(胃損), consumption of Ki & blood(氣血耗盡), overexertion of heart vitality(勞傷心神), deficiency of Yong(營虛), deficiency of Wi(衛虛), deficiency of Yang(陽虛), the treatment of Yang-restoring & exhaustion-arresting(回陽固脫) with RijungTang(理中湯), jinMuTang(眞武湯), SaengMaekSaGunjaTang(生脈四君子湯), Astragali Radix (황기), Ledebouriellae Radix(防風), Cinnamomi Ramulus(桂枝), Angelicae Gigantis Radix(當歸), Ostreae Concha(牡蠣), Zanthoxyli Fructus(川椒), Cuscutae Semen(兎絲子), etc can be applied.

• IMMUNE NETWORK
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• v.14 no.1
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• pp.21-29
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• 2014

Follicular helper T ($T_{FH}$) cells are recently highlighted as their crucial role for humoral immunity to infection as well as their abnormal control to induce autoimmune disease. During an infection, na$\ddot{i}$ve T cells are differentiating into $T_{FH}$ cells which mediate memory B cells and long-lived plasma cells in germinal center (GC). $T_{FH}$ cells are characterized by their expression of master regulator, Bcl-6, and chemokine receptor, CXCR5, which are essential for the migration of T cells into the B cell follicle. Within the follicle, crosstalk occurs between B cells and $T_{FH}$ cells, leading to class switch recombination and affinity maturation. Various signaling molecules, including cytokines, surface molecules, and transcription factors are involved in $T_{FH}$ cell differentiation. IL-6 and IL-21 cytokine-mediated STAT signaling pathways, including STAT1 and STAT3, are crucial for inducing Bcl-6 expression and $T_{FH}$ cell differentiation. $T_{FH}$ cells express important surface molecules such as ICOS, PD-1, IL-21, BTLA, SAP and CD40L for mediating the interaction between T and B cells. Recently, two types of microRNA (miRNA) were found to be involved in the regulation of $T_{FH}$ cells. The miR-17-92 cluster induces Bcl-6 and $T_{FH}$ cell differentiation, whereas miR-10a negatively regulates Bcl-6 expression in T cells. In addition, follicular regulatory T ($T_{FR}$) cells are studied as thymus-derived $CXCR5^+PD-1^+Foxp3^+\;T_{reg}$ cells that play a significant role in limiting the GC response. Regulation of $T_{FH}$ cell differentiation and the GC reaction via miRNA and $T_{FR}$ cells could be important regulatory mechanisms for maintaining immune tolerance and preventing autoimmune diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Here, we review recent studies on the various factors that affect $T_{FH}$ cell differentiation, and the role of $T_{FH}$ cells in autoimmune diseases.