| Virology Journal | |
| Human Polyomavirus JC monitoring and noncoding control region analysis in dynamic cohorts of individuals affected by immune-mediated diseases under treatment with biologics: an observational study | |
| Valeria Pietropaolo6  Anna Teresa Palamara4  Salvatore Cucchiara2  Ada Francia7  Guido Valesini5  Silvia Carluccio8  Lucia Nencioni1  Giovanni Di Nardo2  Federica Ferrari2  Simona Pontecorvo7  Manuela Morreale3  Rossana Scrivo5  Sara Cioccolo9  Donatella Maria Rodio9  Elena Anzivino9  Anna Bellizzi9  | |
| [1] Department of Public Health and Infectious Diseases, Institute Pasteur, Cenci-Bolognetti Foundation, Sapienza University of Rome, Rome, Italy;Department of Pediatrics, Pediatric Gastroenterology and Liver Unit, Sapienza University of Rome, Rome, Italy;Department of Medico-Surgical Sciences and Biotechnologies, Section of Neurology, Sapienza University of Rome, Rome, Italy;San Raffaele Pisana Scientific Institute for Research, Hospitalization and Health Care, Rome, Italy;Department of Internal Medicine and Medical Disciplines, Rheumatology, Sapienza University of Rome, Rome, Italy;Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania, USA;Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy;Department of Biomedical, Surgery and Dental Sciences, University of Milan, via Pascal 36, 20123 Milan, Italy;Department of Public Health and Infectious Diseases, Sapienza University, P.le Aldo Moro, 5, 00185 Rome, Italy | |
| 关键词: VP1; NCCR; anti-TNF; Crohn’s disease; Chronic inflammatory rheumatic diseases; Natalizumab; Multiple sclerosis; JCPyV-specific antibodies; q-PCR; JCPyV; | |
| Others : 821256 DOI : 10.1186/1743-422X-10-298 |
|
| received in 2013-07-04, accepted in 2013-09-27, 发布年份 2013 | |
PDF
|
|
【 摘 要 】
Background
Progressive multifocal leukoencephalopathy (PML) onset, caused by Polyomavirus JC (JCPyV) in patients affected by immune-mediated diseases during biological treatment, raised concerns about the safety profile of these agents. Therefore, the aims of this study were the JCPyV reactivation monitoring and the noncoding control region (NCCR) and viral protein 1 (VP1) analysis in patients affected by different immune-mediated diseases and treated with biologics.
Methods
We performed JCPyV-specific quantitative PCR of biological samples collected at moment of recruitment (t0) and every 4 months (t1, t2, t3, t4). Subsequently, rearrangements’ analysis of NCCR and VP1 was carried out. Data were analyzed using χ2 test.
Results
Results showed that at t0 patients with chronic inflammatory rheumatic diseases presented a JCPyV load in the urine significantly higher (p≤0.05) than in patients with multiple sclerosis (MS) and Crohn’s disease (CD). It can also be observed a significant association between JC viruria and JCPyV antibodies after 1 year of natalizumab (p=0.04) in MS patients. Finally, NCCR analysis showed the presence of an archetype-like sequence in all urine samples, whereas a rearranged NCCR Type IR was found in colon-rectal biopsies collected from 2 CD patients after 16 months of infliximab. Furthermore, sequences isolated from peripheral blood mononuclear cells (PBMCs) of 2 MS patients with JCPyV antibody at t0 and t3, showed a NCCR Type IIR with a duplication of a 98 bp unit and a 66 bp insert, resulting in a boxB deletion and 37 T to G transversion into the Spi-B binding site. In all patients, a prevalence of genotypes 1A and 1B, the predominant JCPyV genotypes in Europe, was observed.
Conclusions
It has been important to understand whether the specific inflammatory scenario in different immune-mediated diseases could affect JCPyV reactivation from latency, in particular from kidneys. Moreover, for a more accurate PML risk stratification, testing JC viruria seems to be useful to identify patients who harbor JCPyV but with an undetectable JCPyV-specific humoral immune response. In these patients, it may also be important to study the JCPyV NCCR rearrangement: in particular, Spi-B expression in PBMCs could play a crucial role in JCPyV replication and NCCR rearrangement.
【 授权许可】
2013 Bellizzi et al.; licensee BioMed Central Ltd.
【 预 览 】
| Files | Size | Format | View |
|---|---|---|---|
| 20140712071453462.pdf | 1122KB | ||
| Figure 3. | 82KB | Image | |
| Figure 2. | 36KB | Image | |
| Figure 1. | 31KB | Image |
【 图 表 】
Figure 1.
Figure 2.
Figure 3.
【 参考文献 】
- [1]Bellizzi A, Nardis C, Anzivino E, Rodìo DM, Fioriti D, Mischitelli M, Chiarini F, Pietropaolo V: Human polyomavirus JC reactivation and pathogenetic mechanisms of progressive multifocal leukoencephalopathy and cancer in the era of monoclonal antibody therapies. J Neurovirol 2012, 18:1-11.
- [2]Padgett BL, Walker DL, Zu Rhein GM, Echroade RJ, Dessel BH: Cultivation of papova-like virus from human brain with progressive multifocal leukoencephalopathy. The Lancet 1971, 1:1257-1260.
- [3]Kean JM, Rao S, Wang M, Garcea RL: Seroepidemiology of human polyomaviruses. PLoS Pathog 2009, 5:e1000363.
- [4]Brew BJ, Davies NW, Cinque P, Clifford DB, Nath A: Progressive multifocal leukoencephalopathy and other forms of JC virus disease. Nat Rev Neurol 2010, 6:667-679.
- [5]Del Valle L, Khalili K: Detection of human polyomavirus proteins, T-antigen and agnoprotein, in human tumor tissue arrays. J Med Virol 2010, 82:806-811.
- [6]Agostini HT, Deckhut A, Jobes DV, Girones R, Schlunck G, Prost MG, Frias C, Pérez-Trallero E, Ryschkewitsch CF, Stoner GL: Genotypes of JC virus in East, Central and Southwest Europe. J Gen Virol 2001, 82:1221-1331.
- [7]Tan CS, Koralnik IJ: Progressive multifocal leukoencephalopathy and other disorders caused by JC virus: clinical features and pathogenesis. Lancet Neurol 2010, 9:425-437.
- [8]Weissert R: Progressive multifocal leukoencephalopathy. J Neuroimmunol 2011, 231:73-77.
- [9]Major EO: Progressive multifocal leukoencephalopathy in patients on immunomodulatory therapies. Annu Rev Med 2010, 61:35-47.
- [10]Carson KR, Focosi D, Major EO, Petrini M, Richey EA, West DP, Bennett CL: Monoclonal antibody-associated progressive multifocal leucoencephalopathy in patients treated with rituximab, natalizumab, and efalizumab: a review from the Research on Adverse Drug Events and Reports (RADAR) project. Lancet Oncol 2009, 10:816-824.
- [11]Bellizzi A, Anzivino E, Rodio DM, Palamara AT, Nencioni L, Pietropaolo V: New insights on Human Polyomavirus JC and pathogenesis of progressive multifocal leukoencephalopathy. Clin Dev Immunol 2013. doi:10.1155/2013/839719
- [12]Bloomgren G, Richman S, Hotermans C, Subramanyam M, Goelz S, Natarajan A, Lee S, Plavina T, Scanlon JV, Sandrock A, Bozic C: Risk of natalizumab-associated progressive multifocal leukoencephalopathy. N Engl J Med 2012, 366:1870-1880.
- [13]Perkins MR, Ryschkewitsch C, Liebner JC, Monaco MC, Himelfarb D, Ireland S, Roque A, Edward HL, Jensen PN, Remington G, Abraham T, Abraham J, Greenberg B, Kaufman C, LaGanke C, Monson NL, Xu X, Frohman E, Major EO, Douek DC: Changes in JC virus-specific T cell responses during natalizumab treatment and in natalizumab-associated progressive multifocal leukoencephalopathy. PLoS Pathog 2012, 8(11):e1003014. doi:10.1371/journal.ppat.1003014
- [14]Sørensen PS, Bertolotto A, Edan G, Giovannoni G, Gold R, Havrdova E, Kappos L, Kieseier BC, Montalban X, Olsson T: Risk stratification for progressive multifocal leukoencephalopathy in patients treated with natalizumab. Mult Scler 2012, 18(2):143-52.
- [15]Berger JR, Houff S: Opportunistic infections and other risks with newer multiple sclerosis therapies. Ann Neurol 2009, 65:367-377.
- [16]Ransohoff RM: Thinking without thinking about natalizumab and PML. J Neurol Sci 2007, 259:50-52.
- [17]Zohren F, Toutzaris D, Klarner V, Hartung HP, Kieseier B, Haas R: The monoclonal anti-VLA-4 antibody natalizumab mobilizes CD34+hematopoietic progenitor cells in humans. Blood 2008, 111:3893-3895.
- [18]Tan CS, Ellis LC, Wuthrich C, Ngo L, Broge TA Jr, Saint-Aubyn J, Miller JS, Koralnik IJ: JC virus latency in the brain and extraneural organs of patients with and without progressive multifocal leukoencephalopathy. J Virol 2010, 84:9200-9209.
- [19]Andreoletti L, Lescieux A, Lambert V, Si-Mohamed A, Matta M, Wattré P, Belec L: Semiquantitative detection of JCV-DNA in peripheral blood leukocytes from HIV-1-infected patients with or without progressive multifocal leukoencephalopathy. J Med Virol 2002, 66:1-7.
- [20]Marzocchetti A, Tompkins T, Clifford DB, Gandhi RT, Kesari S, Berger JR, Simpson DM, Prosperi M, De Luca A, Koralnik IJ: Determinants of survival in progressive multifocal leukoencephalopathy. Neurology 2009, 73:1551-1558.
- [21]Sabath BF, Major EO: Traffic of JC virus from sites of initial infection to the brain: the path to progressive multifocal leukoencephalopathy. J Infect Dis 2002, 186:S180-186.
- [22]Rudick RA, O’Connor PW, Polman CH, Goodman AD, Ray SS, Griffith NM, Jurgensen SA, Gorelik L, Forrestal F, Sandrock AW, Goelz S: Assessment of JC virus DNA in blood and urine from natalizumab-treated patients. Ann Neurol 2010, 68:304-310.
- [23]Gorelik L, Lerner M, Bixler S, Crossman M, Schlain B, Simon K, Pace A, Cheung A, Chen LL, Berman M, Zein F, Wilson E, Yednock T, Sandrock A, Goelz SE, Subramanyam M: Anti-JC virus antibodies: implications for PML risk stratification. Ann Neurol 2010, 68:295-303.
- [24]Laroni A, Giacomazzi CG, Grimaldi L, Gallo P, Sormani MP, Bertolotto A, McDermott JL, Gandoglia I, Martini I, Vitello G, Rinaldi F, Barzon L, Militello V, Pizzorno M, Bandini F, Capello E, Palù G, Uccelli A, Mancardi GL, Varnier OE: Urinary JCV-DNA testing during Natalizumab treatment may increase accuracy of PML risk stratification. J Neuroimmune Pharmacol 2012, 7:665-672.
- [25]Mancuso R, Saresella M, Hernis A, Marventano I, Ricci C, Agostini S, Rovaris M, Caputo D, Clerici M: JC virus detection and JC virus-specific immunity in natalizumab-treated multiple sclerosis patients. J Transl Med 2012, 10:248. doi:10.1186/1479-5876-10-248 BioMed Central Full Text
- [26]Calabrese LH, Molloy ES, Huang D, Ransohoff RM: Progressive multifocal leukoencephalopathy in rheumatic diseases: evolving clinical and pathologic patterns of disease. Arthritis Rheum 2007, 56:2116-2128.
- [27]Molloy ES, Calabrese LH: Progressive multifocal leukoencephalopathy: a national estimate of frequency in systemic lupus erythematosus and other rheumatic diseases. Arthritis Rheum 2009, 60:3761-3765.
- [28]Kothary N, Diak IL, Brinker A, Bezabeh S, Avigan M, Dal Pan G: Progressive multifocal leukoencephalopathy associated with efalizumab use in psoriasis patients. J Am Acad Dermatol 2011, 65:546-551.
- [29]Molloy ES, Calabrese LH: Progressive multifocal leukoencephalopathy associated with immunosuppressive therapy in rheumatic diseases: evolving role of biologic therapies. Arthritis Rheum 2012, 64:3043-3051.
- [30]Kumar D, Bouldin TW, Berger RG: A case of progressive multifocal leukoencephalopathy in a patient treated with infliximab. Arthritis Rheum 2010, 62:3191-3195.
- [31]Marshall LJ, Major EO: Molecular regulation of JC virus tropism: insights into potential therapeutic targets for progressive multifocal leukoencephalopathy. J Neuroimmune Pharmacol 2010, 5:404-417.
- [32]Marshall LJ, Moore LD, Mirsky MM, Major EO: JC virus promoter/enhancers contain TATA box-associated Spi-Bbinding sites that support early viral gene expression in primary astrocytes. J Gen Virol 2012, 93:651-661.
- [33]Bellizzi A, Anzivino E, Ferrari F, Di Nardo G, Colosimo MT, Fioriti D, Mischitelli M, Chiarini F, Cucchiara S, Pietropaolo V: Polyomavirus JC reactivation and noncoding control region sequence analysis in pediatric Crohn’s disease patients treated with infliximab. J Neurovirol 2011, 17:303-313.
- [34]Kurtzke JF: Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS). Neurology 1983, 33:1444-1452.
- [35]Jensen PN, Major EO: A classification scheme for human polyomavirus JCV variants based on the nucleotide sequence of the noncoding regulatory region. J Neurovirol 2001, 7:280-287.
- [36]Frisque RJ, Bream GL, Cannella MT: Human polyomavirus JC virus genome. J Virol 1984, 51:458-469.
- [37]Padgett BL, Walker DL, ZuRhein GM, Hodach AE, Chou SM: JC papovavirus in progressive multifocal leukoencephalopathy. J Infect Dis 1976, 133:686-690.
- [38]Yogo Y, Kitamura T, Sugimoto C, Ueki T, Aso Y, Hara K, Taguchi F: Isolation of a possible archetypal JC virus DNA sequence from nonimmunocompromised individuals. J Virol 1990, 64:3139-3143.
- [39]Elenkov IJ, Chrousos GP: Stress hormones, proinflammatory and antiinflammatory cytokines, and autoimmunity. Ann N Y Acad Sci 2002, 966:290-303.
- [40]Egli A, Infanti L, Dumoulin A, Buser A, Samaridis J, Stebler C, Gosert R, Hirsch HH: Prevalence of polyomavirus BK and JC infection and replication in 400 healthy blood donors. J Infect Dis 2009, 199:837-846.
- [41]Koralnik IJ, Du Pasquier RA, Kuroda MJ, Schmitz JE, Dang X, Zheng Y, Lifton M, Letvin NL: Association of prolonged survival in HLA-A2 progressive multifocal leukoencephalopathy patients with a CTL response specific for a commonly recognized JC virus epitope. J Immunol 2002, 168:499-504.
- [42]Du Pasquier RA, Kuroda MJ, Zheng Y, Jean-Jacques J, Letvin NL, Koralnik IJ: A prospective study demonstrates an association between JC virus specific cytotoxic T lymphocytes and the early control of progressive multifocal leukoencephalopathy. Brain 2004, 127:1970-1978.
- [43]Chen Y, Bord E, Tompkins T, Miller J, Tan CS, Kinkel RP, Stein MC, Viscidi RP, Ngo LH, Koralnik IJ: Asymptomatic reactivation of JC virus in patients treated with natalizumab. N Engl J Med 2009, 361:1067-1074.
- [44]Sadiq SA, Puccio LM, Brydon EW: JCV detection in multiple sclerosis patients treated with natalizumab. J Neurol 2010, 257:954-958.
- [45]Ryschkewitsch CF, Jensen PN, Monaco MC, Major EO: JC virus persistence following progressive multifocal leukoencephalopathy in multiple sclerosis patients treated with natalizumab. Ann Neurol 2010, 68:384-391.
- [46]Sweet TM, Del Valle L, Khalili K: Molecular biology and immunoregulation of human neurotropic JC virus in CNS. J Cell Physiol 2002, 191:249-256.
- [47]Selgrad M, De Giorgio R, Fini L, Cogliandro RF, Williams S, Stanghellini V, Barbara G, Tonini M, Corinaldesi R, Genta RM, Domiati-Saad R, Meyer R, Goel A, Boland CR, Ricciardiello L: JC virus infects the enteric glia of patients with chronic idiopathic intestinal pseudo-obstruction. Gut 2009, 58:25-32.
- [48]Comar M, Secchiero P, De Lorenzo E, Martelossi S, Tommasini A, Zauli G: JCV+ Patients with inflammatory bowel disease show elevated plasma levels of MIG and SCF. Inflamm Bowel Dis 2012, 18:1194-1196.
- [49]Dajotoy T, Andersson P, Bjartell A, Löfdahl CG, Tapper H, Egesten A: Human eosinophils produce the T cell-attracting chemokines MIG and IP-10 upon stimulation with IFN-gamma. J Leukoc Biol 2004, 76:685-691.
- [50]Tan CS, Dezube BJ, Bhargava P, Autissier P, Wüthrich C, Miller J, Koralnik IJ: Detection of JC virus DNA and proteins in the bone marrow of HIV-positive and HIV-negative patients: implications for viral latency and neurotropic transformation. J Infect Dis 2009, 199:881-888.
- [51]Randhawa P, Baksh F, Aoki N, Tschirhart D, Finkelstein S: JC virus infection in allograft kidneys: analysis by polymerase chain reaction and immunohistochemistry. Transplantation 2001, 71:1300-1303.
- [52]Lindberg RL, Achtnichts L, Hoffmann F, Kuhle J, Kappos L: Natalizumab alters transcriptional expression profiles of blood cell subpopulations of multiple sclerosis patients. J Neuroimmunol 2008, 194:153-164.
- [53]Marshall LJ, Dunham L, Major EO: Transcription factor Spi-B binds unique sequences present in the tandem repeat promoter/enhancer of JC virus and supports viral activity. J Gen Virol 2010, 91:3042-3052.
- [54]Monaco MCG, Sabath BF, Durham LC, Major EO: JC virus multiplication in human hematopoietic progenitor cells requires the NF-1 class D transcription factor. J Virol 2001, 75:9687-9695.
- [55]Gallant S, Gilkeson G: ETS transcription factors and regulation of immunity. Arch Immunol Ther Exp (Warsz) 2006, 54:149-163.
- [56]Schmidlin H, Diehl SA, Nagasawa M, Scheeren FA, Schotte R, Uittenbogaart CH, Spits H, Blom B: Spi-B inhibits human plasma cell differentiation by repressing BLIMP1 and XBP-1 expression. Blood 2008, 112:1804-1812.
- [57]Comar M, Delbue S, Lepore L, Martelossi S, Radillo O, Ronfani L, D'Agaro P, Ferrante P: Latent viral infections in young patients with inflammatory diseases treated with biological agents: prevalence of JC virus genotype 2. J Med Virol 2013, 85:716-722.
- [58]Mischitelli M, Fioriti D, Anzivino E, Bellizzi A, Barucca V, Boldorini R, Miglio U, Sica S, Sorà F, De Matteis S, Chiarini F, Pietropaolo V: Viral infection in bone marrow transplants: is JC virus involved? J Med Virol 2010, 82:138-145.
- [59]Major EO: Reemergence of PML in natalizumab-treated patients: new cases, same concerns. N Engl J Med 2009, 361:1041-1043.
- [60]Arnett FC, Edworthy SM, Bloch DA, McShane DJ, Fries JF, Cooper NS, Healey LA, Kaplan SR, Liang MH, Luthra HS, Medsger TA Jr, Mitchell DM, Neustadt DH, Pinals RS, Schaller JG, Sharp JT, Wilder RL, Hunder GG: The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 1988, 31:315-324.
- [61]Taylor W, Gladman D, Helliwell P, Marchesoni A, Mease P, Mielants H, CASPAR Study Group: Classification criteria for psoriatic arthritis. Development of new criteria from a large international study. Arthritis Rheum 2006, 54:2665-2673.
- [62]van der Linden S, Valkenburg HA, Cats A: Evaluation of diagnostic criteria for ankylosing spondylitis. A proposal for modification of the New York criteria. Arthritis Rheum 1984, 27:361-368.
- [63]Fries JF, Spitz PW, Young DY: The dimensions of health outcomes: the Health Assessment Questionnaire, disability and pain scales. J Rheumatol 1982, 9:789-793.
- [64]Lesuis N, Befrits R, Nyberg F, van Vollenhoven RF: Gender and the treatment of immune-mediated chronic inflammatory diseases: rheumatoid arthritis, inflammatory bowel disease and psoriasis: an observational study. BMC Med 2012, 10:82. BioMed Central Full Text
- [65]Garrett S, Jenkinson T, Kennedy LG, Whitelock H, Gaisford P, Calin A: A new approach to defining disease status in ankylosing spondylitis: the Bath Ankylosing Spondylitis Disease Activity Index. J Rheumatol 1994, 21:2286-2291.
- [66]Best WR, Becktel JM, Singleton JW: Rederived values of the eight coefficients of the Crohn's Disease Activity Index (CDAI). Gastroenterology 1979, 77:843-846.
- [67]Frenz MB, Dunckley P, Camporota L, Jewell DP, Travis SP: Comparison between prospective and retrospective evaluation of Crohn's disease activity index. Am J Gastroenterol 2005, 100:1117-1120.
- [68]Present DH, Rutgeerts P, Targan S, Hanauer SB, Mayer L, van Hogezand RA, Podolsky DK, Sands BE, Braakman T, DeWoody KL, Schaible TF, van Deventer SJ: Infliximab for the treatment of fistulas in patients with Crohn's disease. N Engl J Med 1999, 340:1398-1405.
- [69]Lavagna A, Bergallo M, Daperno M, Sostegni R, Costa C, Leto R, Crocellà L, Molinaro G, Rocca R, Cavallo R, Pera A: Infliximab and the risk of latent viruses reactivation in active Crohn's disease. Inflamm Bowel Dis 2007, 13:896-902.
- [70]Bøyum A, Løvhaug D, Tresland L, Nordlie EM: Separation of leucocytes: improved cell purity by fine adjustments of gradient medium density and osmolality. Scand J Immunol 1991, 34(Suppl 6):697-712.
- [71]Delbue S, Branchetti E, Boldorini R, Vago L, Zerbi P, Veggiani C, Tremolada S, Ferrante P: Presence and expression of JCV early gene large T Antigen in the brains of immunocompromised and immunocompetent individuals. J Med Virol 2008, 80:2147-2152.
- [72]Costa C, Bergallo M, Sidoti F, Astegiano S, Terlizzi ME, Mazzucco G, Segoloni GP, Cavallo R: Polyomaviruses BK- and JC- DNA quantitation in kidney allograft biopsies. J Clin Virol 2009, 44:20-23.
- [73]Saiki RK, Scharf S, Faloona F, Mullis KB, Horn GT, Erlich HA, Arnheim N: Enzymatic amplification of β-globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia. Science 1985, 230:1350-1354.
- [74]Pietropaolo V, Videtta M, Fioriti D, Mischitelli M, Arancio A, Orsi N, Degener AM: Rearrangement patterns of JC virus noncoding control region from different biological samples. J Neurovirol 2003, 9:603-611.
- [75]Kwok S, Higuchi R: Avoiding false positive with PCR. Nature 1989, 339:232-238.
- [76]Flaegstad T, Sundsfjord A, Arthur RR, Pedersen M, Traavik T, Subramani S: Amplification and sequencing of the control regions of BK and JC virus from human urine by polymerase chain reaction. Virology 1991, 180:553-560.
- [77]Markowitz RB, Thompson HC, Mueller JF, Cohen JA, Dynan WS: Incidence of BK virus and JC virus viruria in human immunodeficiency virus-infected and uninfected subjects. J Infect Dis 1993, 167:13-20.
- [78]Jobes DV, Friedlaender JS, Mgone CS, Agostini HT, Koki G, Yanagihara R, Ng TCN, Chima SC, Ryschkewitsch CF, Stoner GL: New JC virus (JCV) genotypes from papua new guinea and micronesia (type 8 and type 2E) and evolutionary analysis of 32 complete JCV genomes. Arch Virol 2001, 146:2097-2113.
- [79]ClustalW2 - multiple sequence alignment http://www.ebi.ac.uk/Tools/msa/clustalw2/ webcite
PDF