Impact of interleukin-21 in the pathogenesis of primary Sjogren's syndrome: increased serum levels of interleukin-21 and its expression in the labial salivary glands

Kang, Kwi Young,Kim, Hyun-Ok,Kwok, Seung-Ki,Ju, Ji Hyeon,Park, Kyung-Su,Sun, Dong-Il,Jhun, Joo Yeon,Oh, Hye Jwa,Park, Sung-Hwan,Kim, Ho-Youn BioMed Central 2011 ARTHRITIS RESEARCH AND THERAPY Vol.13 No.5

<P><B>Introduction</B></P><P>Interleukin (IL)-21 is a cytokine that controls the functional activity of effector T helper cells and the differentiation of Th17 cells, and promotes B-cell differentiation. To test whether IL-21 participates in the pathogenesis of primary Sjögren's syndrome (SS), serum IL-21 level was measured and IL-21 expression in the labial salivary glands (LSG) was examined.</P><P><B>Methods</B></P><P>Serum IL-21 levels in 40 primary SS, 40 rheumatoid arthritis (RA), and 38 systemic lupus erythematosus (SLE) patients and 20 healthy controls were measured. Serum IL-21 levels of SS patients were assessed for correlations with laboratory data, including anti-nuclear antibody, anti-Ro/La antibodies, globulin, immunoglobulin (Ig) class, and IgG subclass. LSGs from 16 primary SS and 4 controls with sicca symptoms were evaluated for IL-21 and IL-21 receptor (IL-21R) expression by immunohistochemistry. Confocal microscopy was performed to further characterize the IL-21 positive cells.</P><P><B>Results</B></P><P>Primary SS patients had significantly higher serum IL-21 levels than controls, and these increments correlated positively with levels of IgG, IgG1. Serum IgG1 levels correlated with anti-Ro antibody titers. Immunohistochemical analyses showed that lymphocytic foci and the periductal area of the LSGs from SS patients expressed high levels of IL-21 and lower levels of IL-21R, whereas the control LSGs showed minimal expression of both antigens. The more the lymphocyte infiltrated, IL-21expression in LSGs showed a tendency to increase. Confocal microscopic analyses revealed that IL-21 expressing infiltrating lymphocytes in the LSGs of SS patients also expressed CXCR5.</P><P><B>Conclusions</B></P><P>Primary SS is associated with high serum IL-21 levels that correlate positively with serum IgG, especially IgG1, levels. The expression of IL-21 is increased as more lymphocytes infiltrated in LSGs. These observations suggest that IL-21 may play an important role in primary SS pathogenesis.</P>

Positive and negative roles of interleukin-6 in bone metabolism , inflammation and cell differentiation : application in oriental medical research

Lee, Dong Kyu,Kang, Dong Hwi,Kim, Dong Il,Lee, Tae Kyun,Park, Young Guk,Kim, Cheorl Ho 대한한의학회 부인과학회 2000 大韓韓方婦人科學會誌 Vol.13 No.2

Interleukin 6 (IL-6)은 여러종류의 세포에서 분화 및 주화인자로 작용하는 사이토카인이다. 사람 IL-6의 분자구조는 21에서 28 kDa의 분자량을 갖는 하나의 폴리펩타이드 단백질로서 N-형과 O-형당부가반응과 세린잔기에 인산화를 수반하여 수식되어 있다. 이 사이토카인은 수성의 28-아미노산 자기로 구성된 시그날배열을 가진 212 아미노산의 전구체 단백질로서 생합성된다. IL-6와 가장 밀접한 분자구조를 갖는 물질로는 granulocyte colony-stimulating factor (G-CSF)가 있으며 사람 IL-6의 유전자는 염색체 7p21에 암호화되어 있다. IL-6는 IL-6수용체 (80 kDa subunit, IL-6Ra)의 a-사슬의 세포의 영역과 상호작용을 거쳐 세포표면에 결합하게 되며 이렇게 생성된 결합체는 gp130수용체와 상호작용하며, 이때 gp130 subunit는 JAK/STAT signaling cascade의 계속적인 활성화능력을 보유하도록 리간드-의존적인 2량화 형성이 유도된다. IL-6Ra의 세포내 영역도메인은 신호전달반응에 아무런 역할을 하지 않으며 IL-6Ra의 세포막통과와 세포질도메인이 결여된 수용성 IL-6수용체도 마찬가지로 IL-6와 반웅하며 상승제로서 가능을 하게 된다. 이러한 광범위한 발현과 효과 때문에 IL-6생성의 생체내에서의 부적절한 발현과 조절은 중요한 생리적인 변화를 야기시킨다. 본 총설에서는 생리적이고 병태생리적인 조건에서의 IL-6의 역할과 기능을 검토하였으며 한의학에서의 면역, 천식, 골대사, 당뇨, 암, 순환기계질환, 신경계질환의 약물개발과 기전해석의 수단으로서 검토하였다. Interleukin 6 (IL-6) is a cytokine that functions as a trophic and differentiating factor in cells of many types. Human IL-6 is a single-chain protein with a molecular mass ranging from 21 to 28 kDa. IL-6 is modified by N- and O-glycosylations, as well as by phosphorylation on serine residues. The cytokine is synthesized as a precursor protein of 212 amino acids with a hydrophobic 28-residue signal sequence. Its closest homolog is granulocyte colony-stimulating factor (G-CSF). The gene for human IL-6 is located on chromosome 7p21. IL-6 binds to the cell surface via an interaction with the extracellular region of the a-chain of the IL-6 receptor (80 kDa subunit, IL-6Ra). This complex then associates with the gp130 receptor. The gpl30 subunit undergoes ligand-dependent dimerization with subsequent activation of the JAK/STAT signaling cascade. The intracellular domain of IL-6Ra does not play a role in signal transduction. The soluble IL-6 receptor, which lacks the transmembrane and cytoplasmic domain of IL-6Ra, is also responsive to IL-6 and acts as an agonist. Because of its wide-ranging expression and effects, the inappropriate expression and modulation of IL-6 production has important physiological consequences. Presently, it was examined that role of IL-6 under physiological and pathophysiological conditions, and its feasibility as a drug discovery target are meaningful in fields of oriental medical research.

Two-Track Medical Treatment Strategy According to the Clinical Scoring System for Chronic Rhinosinusitis

Kim, Dong-Kyu,Kang, Seong Il,Kong, Il Gyu,Cho, Young Hoon,Song, Seul Ki,Hyun, Se Jin,Cho, Sung Dong,Han, Sang-Yoon,Cho, Seong-Ho,Kim, Dae Woo The Korean Academy of Asthma, Allergy and Clinical 2018 Allergy, Asthma & Immunology Research Vol.10 No.5

<P><B>Purpose</B></P><P>The previously reported Japanese clinical scoring study (JESREC) suggests that chronic rhinosinusitis (CRS) can be divided into 4 subtypes according to the degree of eosinophilic CRS (ECRS) and offers the information regarding the prognosis of CRS to clinicians. However, this scoring system has not yet been validated by an immunological study and needs to provide treatment guidelines based on underlying immunologic profiles. We investigated the immunologic profile of each CRS subgroup according to the JESREC classification and suggest its clinical application.</P><P><B>Methods</B></P><P>A total of 140 CRS patients and 20 control subjects were enrolled. All patients were classified into 4 groups according to the JESREC (non-, mild, moderate and severe ECRS). Nasal tissues were analyzed for mRNA expression of major cytokines (IL-5, IL-10, IL-13, IL-17A, IL-22, IL-23p19, IFN-γ, periostin, thymic stromal lymphopoietin [TSLP] and ST2), major chemokines (CCL11, CCL24, CXCL1 and CXCL2), transcription factors (T-bet, GATA3, RORC and FOXP3) and COL1A1 for type I collagen. Protein levels of 3 major cytokines (IL-5, IL-17A and IFN-γ) were also measured by multiplex immunoassay. Principal component analysis (PCA) was conducted to investigate the overall profile of multiple mediators.</P><P><B>Results</B></P><P>The moderate/severe ECRS showed up-regulation of type 2-related mediators (IL-5, IL-13, periostin, TSLP and ST-2), whereas INF-γ (type 1 cytokine) and CXCL1 (neutrophil chemokine) expressions were increased in non-/mild ECRS compared with moderate/severe ECRS. The JESREC classification reflected an immunological endotype. In PCA data, PCA1 indicates a relative type 2 profile, whereas PCA2 represents a type 1/type 17-related profile. In this analysis, mild ECRS was indistinguishable from non-ECRS, whereas moderate to severe ECRS showed a distinct distribution compared with non-ECRS. The JESREC classification could be divided into 2 categories, non-/mild vs. moderate/severe ECRS based on underlying immunological analyses.</P><P><B>Conclusions</B></P><P>The CRS clinical scoring system from the JESREC study reflects an inflammatory endotype. However, the immunologic profile of mild ECRS was similar to that of non-ECRS. Therefore, we propose type 2-targeted medical treatment for moderate to severe ECRS and type 1/type 17-targeted for non-ECRS and mild ECRS as the first treatment option.</P>

Acetyl salicylic acid inhibits Th17 airway inflammation via blockade of IL-6 and IL-17 positive feedback

문형근,Chil Sung Kang,최준표,최동식,Hyun Il Choi,최용욱,전성규,유주연,Myoung Ho Jang,고용송,김윤근 생화학분자생물학회 2013 Experimental and molecular medicine Vol.45 No.1

T-helper (Th)17 cell responses are important for the development of neutrophilic inflammatory disease. Recently, we found that acetyl salicylic acid (ASA) inhibited Th17 airway inflammation in an asthma mouse model induced by sensitization with lipopolysaccharide (LPS)-containing allergens. To investigate the mechanism(s) of the inhibitory effect of ASA on the development of Th17 airway inflammation, a neutrophilic asthma mouse model was generated by intranasal sensitization with LPS plus ovalbumin (OVA) and then challenged with OVA alone. Immunologic parameters and airway inflammation were evaluated 6 and 48 h after the last OVA challenge. ASA inhibited the production of interleukin (IL)-17 from lung T cells as well as in vitro Th17 polarization induced by IL-6. Additionally, ASA, but not salicylic acid, suppressed Th17 airway inflammation,which was associated with decreased expression of acetyl-STAT3 (downstream signaling of IL-6) in the lung. Moreover, the production of IL-6 from inflammatory cells, induced by IL-17, was abolished by treatment with ASA, whereas that induced by LPS was not. Altogether, ASA, likely via its acetyl moiety, inhibits Th17 airway inflammation by blockade of IL-6 and IL-17positive feedback.

Free Paper Session : Upper Gastrointestinal Tract 1 ; Prevalence And Risk Factors For Atrophic Gastritis And Intestinal Metaplasia

( Na Young Kim ),( Dong Ho Lee ),( Joo Sung Kim ),( Hyun Chae Jung ),( In Sung Song ),( Kyung Phil Kang ),( Jung Hoon Lee ),( Jae Il Chung ),( Hyun Cheul Choi ),( Taek Man Nam ),( Sang Hyup Lee ),( Yo 대한소화기학회 2007 SIDDS Vol.9 No.-

Background/Aims: The prevalence of gastric cancer and Helicobacter pylori (Hp) infection is high in Korea. This study was performed to evaluate the prevalence rate of atrophic gastritis (AG) and intestinal metaplasia (IM) and their risk factors in the aspect of Hp virulence factors, environmental and host factors in normal population. Methods: The subjects consisted of 389, 135 H. pylori-negative and 254 H. pylori-positive. AG and IM were scored histologically by the Sydney classification in the antrum and body, respectively. Prevalence rate and bacterial factors such as cagA, vacA m1, m2, and oipA; environmental factors such as smoking, alcohol drinking; host factors such as genetic polymorphisms for IL-IB-511, IL-IRN, TNF-A, IL-10-592, IL-10-819, IL-10-1082, IL-8-251, IL-6-572, GSTP1, and p53 codon 72 were evaluated. Risk factors were calculated by multiple logistic regression analysis. Results: The prevalence rate of AG increased from 25%, 0% in the age of 20s, 45% and 22% in the 40s and 50% and 35% in the over 70s in the antrum and body, respectively (p<0.001). In case of IM it increased from 11.1% and 6.4% in the 30s up to 43% and 43% in over 70s in the antrum and body, respectively, (p<0.001). The positive rates of AG and IM were significantly higher in the Hp-positive than in the Hp-negative subjects. Multivariate analysis showed that the risk factors for AG were Hp infection, age ≥60, cagA and vacA m1 positive. In case of IM the risk factors were Hp infection, age ≥60, smoking, spicy food, occupation (unemployed or non professional vs. professional), IL6-572 G carrier over C/C and IL10-592 C/A vs. A/A. Conclusions: The prevalence rate of AG and IM increased proportional to age. The most risk factor for AG and IM was Hp infection. Bacterial factors were important for AG but environmental and host factors were rather important in case of IM.

Chronological changes in inflammatory cytokines immunoreactivities in the mouse hippocampus after systemic administration of high dosage of tetanus toxin.

Yan, Bing Chun,Park, Joon Ha,Kim, In Hye,Shin, Bich Na,Ahn, Ji Hyeon,Yoo, Ki-Yeon,Lee, Deuk-Sik,Kim, Myong Jo,Kang, Il-Jun,Won, Moo-Ho Springer-Verlag 2012 Experimental brain research Vol.223 No.2

<P>Tetanus toxin (TeT) is an exotoxin and has a capacity for neuronal binding and internalization. In the present study, we compared changes in the immunoreactivities and protein levels of interleukin (IL-) 2 as a pro-inflammatory cytokine and IL-4 as an anti-inflammatory cytokine in the hippocampus proper (HP) and dentate gyrus (DG) after systemic treatment of 10 or 100?ng/kg TeT into mice. In this study, we could not find any neuronal damage or loss in any subregions of the hippocampus after TeT treatment. In the control groups, strong IL-2 immunoreactivity was shown in the stratum pyramidal (SP) of the HP and in the granule cell layer (GCL) of the DG. At 6?h post-treatment, IL-2 immunoreactivity was hardly detected in the SP and GCL; however, strong IL-2 immunoreactivity was shown in the stratum oriens of the HP in both the groups. Thereafter, intermediate IL-2 immunoreactivity was shown in the SP and GCL. On the other hand, intermediate IL-4 immunoreactivity was detected in the SP and GCL of the control groups. At 6?h post-treatment, IL-4 immunoreactivity in the SP and GCL was apparently increased. Thereafter, IL-4 immunoreactivity was lower than that at 6?h post-treatment. In brief, IL-2 and 4 immunoreactivities were easily detected in SP and GCL in the controls and dramatically decreased and increased at 6?h post-treatment, respectively.</P>

골수이식 후 사이토카인과 골교체 생화학적표지자의 변화 및 상관관계

민우성,강무일,한제호,강성구,오기원,이원영,김혜수,문성대,손현식,신완식,김춘추,윤건호,차봉연,이광우,손호영 대한내분비학회 2000 Endocrinology and metabolism Vol.15 No.1

Background : Loss of bone mass is usually detected after BMT. The causes of bone loss are related with gonadal dysfunction and immunosuppressants. Cytokines, especially IL-6, play an important role in the pathogenesis of postmenopausal osteoporosis. However, the pathogenetic role of cytokines in post-BMT bone loss is unknown and data on the changes of cytokines in accordance with bone turnover markers are scarce. The aim of this study is to assess the relationship of bone turnover markers and cytokines of peripheral blood and bone marrow before and after allogeneic BMT. Methods : This prospective study included two analyses. The first was a study of 46 BMT recipients, examining the relationship between bone turnover markers and cytokines of serum which were measured before and 1, 2, 3, 4 week and 3 months after BMT. The second was a study of 14 BMT patients, measuring bone marrow plasma cytokines such as IL-6 and TNF-? at post-BMT 3 week and bone turnover marker at the same time to assess the relationship beween two parameters. Results : Serum ICTP, bone resorption marker, increased progressively until 4 weeks (peak) after BMT and then decreased thereafter. Serum osteocalcin, bone formation marker, decreased progressively until 3 weeks after BMT and then increased thereafter. There was positive correlation between serum ICTP and bone marrow IL-6 levels at the post-BMT 3 week with a statistical significance, but the correlation between bone turnover markers and bone marrow TNF-? or peripheral blood cytokines was not found. Conclusion : Our data suggest that the progressive increase of bone resorption after BMT is related with the increase of bone marrow IL-6, which is a potent stimulator of bone resorption in vivo(J Kor Soc Endocrinol 15:85-96, 2000).

Cynara scolymus L. Inhibits the LPS-induced Inflammatory Reaction via Suppression of NF-κB Activity in RAW 264.7 Cells

Kyung-Jun Boo(Kyung-Jun Boo),Kiman Lee(Kiman Lee),Il-Ho Park(Il-Ho Park),Tae Jin Kang(Tae Jin Kang) 대한약학회 2023 약학회지 Vol.67 No.1

Cynara scolymus L. (artichoke) has been traditionally used in the treatment of digestive-related disease, severe hyperlipidemia and liver disease. Recently, anti-inflammatory effect of artichoke has been reported by several studies, but its mechanisms are still unclear. In this study, the anti-inflammatory mechanism of artichoke was studied using an in vitro acute inflammation model. The effect of artichoke on the expression of pro-inflammatory cytokines, such as interleukin- 1beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) in murine macrophage cell line, RAW264.7, was examined by using ELISA and RT-PCR. As a result, artichoke inhibited the expression of IL-1β, IL-6 and TNF-α in macrophages activated by lipopolysaccharide (LPS) at a dose dependent manner. The expression of inflammatory mediators such as NO and PGE2 was next investigated in RAW264.7 cells stimulated with LPS. Artichoke also inhibited the production of NO and PGE2 in the cells at a dose dependent manner. Artichoke suppressed the mRNA expression of iNOS and COX-2 in macrophages by LPS. The effect of artichoke on the activation of NF-κB was examined and LPS-induced NF-κB activation was decreased by treatment of artichoke, suggesting that artichoke has anti-inflammatory effect by inhibiting NF- κB activation.

다탐색(多探索) 법을 통한 저자극성 액체 세정제 조성물 개발

김배환 ( Peter Kim ),현기안 ( Ki-an Hyeon ),정지윤 ( Ji-youn Chung ),윤삼숙 ( Sanm-sook Yoon ),강한철 ( Han Chyul Kang ),박선희 ( Sun Hee Park ),고강일 ( Kang Il Ko ),김기호 ( Ki Ho Kim ) 대한화장품학회 2005 대한화장품학회지 Vol.31 No.1

세정제에 널리 상용화되어 있는 알킬에톡시설페이트 계의 음이온 계면활성제는 피부 흡착의 특성 때문에 충분히 헹구어 내지 않으면 피부에 잔존되어 자극의 원인이 되어 염증 반응을 일으키게 된다. 따라서 기존의 음이온 계면활성제를 대체 또는 보완하기 위해 기존의 계면활성제들을 단백질 변성 실험, 세포 독성 그리고 IL-1α 측정을 통해 선별하였다. 본 연구는 저자극성의 음이온 또는 비이온, 양쪽성 이온의 14종의 계면활성제와 민감성 피부를 위해 제조된 13종의 기존 세정제 제품에 대한 세포독성을 실시하여, 가장 독성이 낮은 계면활성제로 sodium laureth sulfate (음이온), sodium cocoyl isethionate (음이온), sodium lauroamphoacetate (양성이온), cocamidopropyl betaine (양성이온), alkyl polyglycoside (비이온)가 선택되었고 2종의 기존 세정제 제품을 비교 제형으로 선택하였다. 5종의 계면활성제를 20종의 formulation으로 제조하여 단백질 변성(<3M SLS (13.2%)), 세포독성 실험 및 폐첩포 실험을 통하여 다시 5종을 선별하였다. 이들 제형을 진피 배양으로 세포독성 및 IL-1α 방춘량을 조사하여 가장 자극이 낮은 계면활성제 제형을 선택하였으며, 첨가된 계면활성제의 자극을 완화하기 위하여 항염과 보습 효과가 우수한 마치현 추출물(3%, 5%)과 fructan (3%, 5%)을 농도별로 첨가한 제형을 제조하여 가장 안전성이 뛰어난 농도를 선택하였다. 최종적으로 선택된 제형 5번을 3차원 세포 배양을 통한 인공피부를 이용하여 가장 자극이 낮게 나타난 기존의 제품들과 세포 독성 및 IL-1α 방출량을 비교 조사하여 저자극성의 액체 세정제를 개발하였다. Alkyl ethoxy sulfate type surfactants, widely used in commercial cleansers, are easily adsorbed to skin to often cause skin irritation and inflammation if not thoroughly rinsed nut. In order to replace or complement existing surfactants, we screened the existing surfactants through protein denaturation method, cell cytotoxicity assay and human IL-1α assay, etc. Fourteen surfactants have been chosen from among too irritant anionic, cationic and/or zwitter-ionic ones and investigated for cell cytotoxicity in human fibroblast cell lines using monolayer culture with the thirteen commercially available cleansers for sensitive skin. From these results, we selected 5 surfactants and 2 commercial cleansers (names not shown), such as sodium laureth sulfate (anionic), sodium cocoyl isethionate (anionic), sodium lauroamphoacetate (zwitter-ionic), and cocamidopropyl betaine (zwitter-ionic), alkyl polyglycoside (non-ionic). 20 formulations were made out of 5 surfactants and five of them were chosen through a protein denaturation method (lower than 3 M sodium dodecyl sulfate solution (13.2%)), cell cytotoxicity and human patch test. These five selected formulations containing preservatives were compared to two selected commercial cleansers by cell cytotoxicity and human IL-1α ELISA assay using dermal equivalent. Finally, we selected the best formulation. To this formulation, fructan (3% or 5%) or/and portulaca extract (3% or 5%) well known for its anti-inflammatory and moisturizing effects were added and investigated for cell cytotoxicity using dermal equivalent. In cytotoxicity assay using dermal equivalent, two formulations containing 5% fructan and 3% or 5% portulaca extract were less toxic than the others. In cytotoxicity assay and human IL-1α ELISA using 3D culture, the selected formulation containing 5% fructan and 5% portulaca extract showed better efficiency than those of the others and 2 commercial cleansers. As a result, we could develop a low irritant and safe liquid cleanser.

<i>In vivo</i> genotoxicity evaluation of lung cells from Fischer 344 rats following 28 days of inhalation exposure to MWCNTs, plus 28 days and 90 days post-exposure

Kim, Jin Sik,Sung, Jae Hyuck,Choi, Byung Gil,Ryu, Hyeon Yeol,Song, Kyung Seuk,Shin, Jae Hoon,Lee, Jong Seong,Hwang, Joo Hwan,Lee, Ji Hyun,Lee, Gun Ho,Jeon, Kisoo,Ahn, Kang Ho,Yu, Il Je Informa Healthcare 2014 INHALATION TOXICOLOGY Vol. No.

<P>Despite their useful physico-chemical properties, carbon nanotubes (CNTs) continue to cause concern over occupational and human health due to their structural similarity to asbestos. Thus, to evaluate the toxic and genotoxic effect of multi-wall carbon nanotubes (MWCNTs) on lung cells <I>in vivo</I>, eight-week-old rats were divided into four groups (each group = 25 animals), a fresh air control (0 mg/m<SUP>3</SUP>), low (0.17 mg/m<SUP>3</SUP>), middle (0.49 mg/m<SUP>3</SUP>), and high (0.96 mg/m<SUP>3</SUP>) dose group, and exposed to MWCNTs <I>via</I> nose-only inhalation 6 h per day, 5 days per week for 28 days. The count median length and geometric standard deviation for the MWCNTs determined by TEM were 330.18 and 1.72 nm, respectively, and the MWCNT diameters ranged from 10 to 15 nm. Lung cells were isolated from five male and five female rats in each group on day 0, day 28 (only from males) and day 90 following the 28-day exposure. The total number of animals used was 15 male and 10 female rats for each concentration group. To determine the genotoxicity of the MWCNTs, a single cell gel electrophoresis assay (Comet assay) was conducted on the rat lung cells. As a result of the exposure, the olive tail moments were found to be significantly higher (<I>p</I> < 0.05) in the male and female rats from all the exposed groups when compared with the fresh air control. In addition, the high-dose exposed male and middle and high-dose exposed female rats retained DNA damage, even 90 days post-exposure (<I>p</I> < 0.05). To investigate the mode of genotoxicity, the intracellular reactive oxygen species (ROS) levels and inflammatory cytokine levels (TNF-α, TGF- β, IL-1, IL-2, IL-4, IL-5, IL-10, IL-12 and IFN-γ) were also measured. For the male rats, the H<SUB>2</SUB>O<SUB>2</SUB> levels were significantly higher in the middle (0 days post-exposure) and high- (0 days and 28 days post-exposure) dose groups (<I>p</I> < 0.05). Conversely, the female rats showed no changes in the H<SUB>2</SUB>O<SUB>2</SUB> levels. The inflammatory cytokine levels in the bronchoalveolar lavage (BAL) fluid did not show any statistically significant difference. Interestingly, the short-length MWCNTs deposited in the lung cells were persistent at 90 days post-exposure. Thus, exposing lung cells to MWCNTs with a short tube length may induce genotoxicity.</P>