5Failure to respond to appropriate anti-P. carinii therapy
6The Growing Family of Viral Pathogens in Transplantation HERPES SIMPLEXVARICELLA ZOSTEREPSTEIN-BARR VIRUSCYTOMEGALOVIRUSHHV6 (& role with CMV)HHV7 (role?)HHV8/KSHVHIVWEST NILE VIRUSRABIESHEPATITIS B and CPAPILLOMAVIRUSPOLYOMAVIRUS BK/JCADENOVIRUS, RSVINFLUENZA, PARAINFLUENZAMETAPNEUMOVIRUSPARVOVIRUS B19SMALLPOX/VACCINIASARS coronavirus
7Effects of Viral Infection in Transplantation DIRECT CAUSATION OF INFECTIOUS DISEASE SYNDROMESNephrtitis, hepatitis, neutropeniaAllograft injury often greater than systemicIMMUNOMODULATORY EFFECTSSYSTEMIC IMMUNE SUPPRESSION -- OI’sCELLULAR EFFECTS - Graft Rejection, GvHDABROGATION OF TOLERANCEONCOGENESISHepatitis B: hepatocellular carcinomaEpstein Barr Virus: B-cell lymphoma (PTLD)Hepatitis C: splenic lymphoma (villous lymphocytes)Papillomavirus: Squamous cell & anogenital cancerHHV8 (KSHV): Kaposi’s sarcoma, effusion lymphoma
8CMV: Direct Effects Endothelial & smooth muscle cells, PBMC Macrophages in the lungsPancreas?Retina?Virus activated by allogeneic response, antilymphocyte antibodies, TNF (via NF-B), other proinflammatory cytokinesAJ Koffron et al, J Virol, 1998, 72:95-103; E. Fietz et al, Transplantation, 1994, 58: ; P. Reinke et al, Transplant. Infect Dis, 1999, 1: ; M Hummel et al, J Virol, 2001, 75:
11CMV cecal ulceration in patient with negative antigenemia and PCR assays for CMV
12CMV “Indirect Effects”: Possible Mechanisms Upregulation of MHC class II antigens and homolog of MHC class-I (HLA-DR, Fujinami RS, et al. J Virol. 1988;62: S. Beck, Nature. 1988;331: )Blocks CD8+ (MHC class I) recognitionBlocks CMV antigen processing and display (immediate early Ag modification, poor CTL response)Increased ICAM-1, VCAM, cellular myc & fosInversion of CD4/CD8 ratio (Schooley 1983, Fishman 1984)Increased cytokines: IL-1, TNF, IFN, IL-10, IL-4, IL-8, IL-2/IL-2R, C-X-C chemokines and IL-8 (Kern et al, 1996; CY Tong, 2001)Increased cytotoxic IgM (Baldwin et al, 1983)Stimulation of alloimmune response by viral proteins (Fujinami et al, 1988, Beck et al, 1988)Increased PDGF, TGFIncreased granzyme B CD8+ T-cells, -T-cells
13CMV: Likely Indirect Effects Indirect effects observed clinically are often uncertain given exogenous immune suppression, rejection, drugsOpportunistic infectionsCo-factor to EBV in PTLDHHV6 infectionGraft rejection (acute and chronic)Vanishing bile duct syndrome (if it exists)Co-factor in Bronchiolitis Obliterans SyndromeAccelerated atherogenesis in cardiac allografts
14Opportunistic Infections Promoted by CMV Infection in Transplant Patients Pneumocystis cariniiFungal infections (esp. intra-abdominal transplants):Candidemia and intra-abdominal infection in OLTx; patients with initial poor graft functionAspergillus spp. Role of CMV in promoting fulminant HCV hepatitis rather than direct effectBacteremia: Listeria monocytogenesEpstein-Barr virus infection (RC Walker et al, CID, 1995, 20: )HCV: risk for cirrhosis, retransplantation, mortality
15CMV and Graft Dysfunction: Renal Distinguish between studies demonstrating link of CMV to graft dysfunction and improved outcomes with prevention - may be the same or different effects (Herpes Virus Infection Syndrome)CMV Disease causes poor renal graft function at 6 mos and CMV & HHV6 are associated with chronic dysfunction (3 yrs) (CY Tong et al, Transplant , 74:576-8)Acute but not Chronic allograft rejection is reduced by CMV prevention in liver and kidney (D+/R-) Tx (D Lowance et al, NEJM 1999, 340: ; E. Gane et al, Lancet 1998, 350: )HHV6 increases CMV infection and OI’s and possibly some acute rejection in renal (A. Humar, Transplant 2002, 73: ) & liver recipients (JA DesJardin CID 2001, 33: ; PD Griffiths et al, J Antimicrob Chemother, 2000, 45 sup 29-34)HHV7 associated with increased CMV infection and with acute rejection (IM Kidd et al, Transplant 2000, 69:2400-4)
16CMV and Graft Dysfunction: Liver CMV is associated with cirrhosis, graft failure, retransplantation, and death in liver allograft recipients (KW Burak et al, Liver Transplant 2002, 8:362-9)CMV is associated with more aggressive HCV recurrence and fibrosis after OLTx (partially attributed to HHV6) (A. Sanchez-Fueyo et al, Transplant 2002, 73:56-63; N Singh et al, Clin Transplant 2002, 16:92-6; HR Rosen et al, Transplant 1997, 64:721; R. Patel et al, Transplant 1996, 61:1279)Roles of immune suppression, CMV-induced immune suppression & HCV, CMV-induced TGF/fibrosis
17Impact of CMV in Heart & Lung Transplantation Obliterative bronchiolitis (BOS) increased in:Serologic R+ and D+ combinationRole of asymptomatic CMV replication?CMV infection raises OB to ~60% (Zamora MR. TransID 2001; 3: and Am J Tx 2004, 4: )Infection of vascular endothelia and smooth muscle cells Adhesion molecules (VCAM,ICAM,LFA-1,VLA-4) HLA-DR and MHC Class I mimic Anti-endothelial Abs? Cytotoxic T-cells?
18CMV and Graft Dysfunction: Heart-Lung CMV is associated with Coronary allograft vasculopathy (MT Grattan et al, J Am Med Assoc 1989,261:3562-6)Prophylaxis using CMVIg with ganciclovir reduces cardiac transplant vasculopathy (HA Valantine et al, Circulation 1999, 100:61-6; HA Valentine et al, Transplantation 2001, 72: )CMVIG plus DHPG reduced CMV incidence, rejection, and death vs. DHPG aloneCoronary Tx vasculopathy reducedLung and heart-lung recipients had less obliterative brohchiolitis, death from OB, better survival, fewer infectionsLess PTLD in double RxCMV disease and D+/R- status are associated with chronic rejection, bacterial and fungal pneumonia, OB and death in Lung Tx (SR Duncan 1992; NA Ettinger 1993; K Bando 1995; RE Girgis 1996; RN Husni 1998)Reduction in BOS and fungus with iv ganciclovir (SR Duncan et al, Am J Crit Care Resp Dis 1994, 150: ; DR Snydman NEJM 1987, 317: ; JA Wagner et al Transplant 1995, 60:1473-7)
19Special Risks for CMV in Heart & Lung Transplantation? Lungs:Exposure to environment (stimulation)Lymphatic tissue with graftMacrophage burden with graftMajor site of viral “latency” (Balthesen M et al, J Virol 1993; 67: )Recurrent infections - stimulation
20How best to impact indirect effects? Does prophylaxis delay or prevent CMV infection and disease? - Yes (M Halme Transplant Int 1998, S ; JL Kelly et al, Transplant 1995, 59:1144-7)Does prophylaxis delay or prevent CMV-mediated effects? Role of CMV may be uncertain but clinical data support this concept.Do we need to prevent other viral infections? YesHow to best use “screening tests” depends on goal of therapy - prevent CMV disease vs. asymptomatic infection & presumed indirect effects?What is the optimal regimen? Need further data.
21Summary: Effects of Antiviral Agents on Allograft Injury Valacyclovir in kidney recipients 50% in rejectionOral ganciclovir in heart, liver, kidney recipients trend in rejectionProphylactic IV ganciclovir in heart recipients long-term benefit in of vasculopathyUnfortunately, we do not know much about the effect of antivirals at this point. Valacyclovir, the valine ester of acyclovir, is more effective than placebo in terms of prophylaxis, and it has been shown to reduce rejection rates among kidney recipients.1 Ganciclovir is an extremely potent anti-CMV drug. When administered for 1 month to heart transplant recipients, IV ganciclovir provided a long-term benefit as evidenced by a decrease in vasculopathy in seropositive recipients.2 To date, a trend toward a decrease in rejection has been seen with oral ganciclovir.3,4Lowance D, et al, for the International Valacyclovir Cytomegalovirus Prophylaxis Transplantation Study Group. N Engl J Med. 1999;340:Valantine HA, et al. Circulation. 1999;100:61-66.Ahsan N, et al. Clin Transplant. 1997;11:
22Indirect Effects of CMV: Summary Renal: Decreased early graft function and some chronic dysfunction (increased by HHV6 and HHV7)Acute but possibly not chronic allograft rejection is reduced by CMV prophylaxisLiver: CMV associated with cirrhosis, graft failure, need for retransplantation & deathMore aggressive HCV recurrence and fibrosis after OLTx (partially attributed to HHV6)CMV disease is preventableHeart: cardiac allograft vasculopathyReduced by ganciclovir +/- CMV IgLungs: CMV and D+/R- associated with Bronchiolitis Obliterans Syndrome, infection, deathReduced by iv ganciclovir +/- CMV IgPancreas: Not studied (no CMV yet in islets)
23Indirect Effects: Other Viruses Cytomegalovirus: best studied, global immune suppression, increased graft rejectionHepatitis B and C: increased incidence of opportunistic infectionEpstein-Barr virus: link to non-Hodgkin's lymphomaParvovirus B19: elaboration of cytokines, autoimmune effects, Cellular apoptosisRSV, Coronavirus, influenza: ciliary injury, local suppression
24“Herpes Virus Infection Syndrome” in Transplant Patients HHV6 and HHV7 are risk factors for CMV disease, invasive fungal infection (DH Dockrell et al, Transplant. 1999, JID, 1997; S. Chapenko et al, Clin Transplant 2000, 14:486-92; CY Tong et al, Transplant 2000, 70:213-6; IM Kidd et al, Transplant 2000, 69:2400-4) CMV D+/R- and D-/R+ groups with invasive disease more likely to have co-infection with HHV6, HHV7)HHV6 and HHV7 associated with positive CMV antigenemia in liver Tx (I. Lautenschlager, J. Clin Virol 2002)HHV6 and CMV associated with more severe recurrence/fibrosis with HCV (A. Humar et al, Am J Transplant 2002)Ganciclovir reduces load of all 3 viruses (JC Mendez et al, JID, 2001; 183: ) while CMVIg does not (JA Desjardins et al, JID, 1998, 178:1783-6).
26Examples: Parvovirus B19 Ubiquitous virus (50-90%) of children and adults. Spread by contact, transfusion.Peak incidence in late Winter and early Spring.DNA virus, 5600 bp. Features:Tropism for erythroid cells via P-glycoprotein (glyboside)Causes elaboration of cytokinesCellular apoptosis (caspase 3 inhibition via down-regulation of Bcl-2)Cellular cytotoxicity in vitro (in vivo?)
27Parvovirus B19 - Myocarditis Lymphocytic myocarditis in an 11 mo child (Papadogiannakis et al, CID 2002: 35, 1027)Patchy necrosis of myocardiumMononuclear cell infiltration of myocardium, lungsNormal bone marrowAnemia, lymphocytic myocarditis 2 mos post cardiac transplantation
28Parvovirus: Mechanisms P-receptor bindingErythroid precursors (fetal anemia, hydrops?) Giant pronormoblasts with intranuclear inclusions, vacuolesMegakaryoblasts (platelets)Endothelial cells (vasculitis)Myocardial cells (myocarditis uncommon but may be rapid and severe in normal hosts) (Porter et al, Lancet 1988; 1, 535-6; Naides & Weiner, Prenat Dx 1989; 9: )Autoimmune via-T-cells? (Eck et al, Am J Surg Path 1997; 21: )Lower level of virus in heart vs other unaffected tissues (Murray et al, Hum Path 2001, 32:342-5)CD8+ cell recruitment (Tolfuenstam et al, J Virol. 2001; 75:540)
30RSV: Pediatric Liver Transplant Recipients 3.5% of 493 children >5 years; median, 20 months old76% nosocomial; median, 24 days posttransplantationTachypnea 65%, cough 53%, fever 53%, wheeze 29%, pneumonia 35%Coinfections: bacteremia/fungemia 35%, fungal/bacterial pneumonia 24%, CMV 24%No ribavirin therapy: mortality 12%Peigue-Lafeuille H, Gazuy N, Mignot P, Deteix P, Beytout D, Baguet JC. Severe respiratory syncytial virus pneumonia in an adult renal transplant recipient: successful treatment with ribavirin. Scand J Infect Dis 22:87-9, 1990.Pohl C et al. J Infect Dis. 1992;165:
31Parainfluenza in Lung Transplant Recipients Median onset, 2.1 years (range, 0.6-5) posttransplantationPresenting symptomsCough 71%Shortness of breath 64%Fever 17%Pneumonia 17%18 (82%) had concurrent rejection; 32% progressed to bronchiolitis obliterans9 of 10 treated with ribavirin survivedVilchez RA, et al. Clin Infect Dis. 2001;33: Wendt CH et al. J Heart Lung Transplant : Hayden FG et al. Antivir Ther. 1996;1:51-56.
32Indirect Effects and Respiratory viral infections RVI increased risk of 2.1 fold for development of Aspergillus infections.(13)RVI risk factor for graft rejection, particularly chronic graft rejection in lung transplants.(14-19)RVI of the lower respiratory tract, but not the upper tract, predispose to bronchiolitis obliterans syndrome (BOS) (RR, 2.3; 95% CI, ).(14)Rat lung transplant model of Sendai virus infection, a virus related to parainfluenza virus (PIV) links lower tract disease and BOS.(20)Seasonal trend to BOS that peaks shortly after the peak of winter respiratory viral infections.(5)Marr KA et al. Blood 2002;100(13): ; Billings JL et al. J Heart Lung Transplant 2002;21(5):559-66; Chakinala MM, Walter MJ. Semin Thorac Cardiovasc Surg 2004;16(4):342-9.; Garantziotis S et al. 2001;119(4): ; Khalifah AP at al. Am J Respir Crit Care 2004;170(2):181-7; Vilchez RA et al. Am J Transplant 2003;3(3):245-9; Winter JB et al. Transplant. 1994;57(3):418-22).
33Where Do Indirect Effects Stop and Where Does Oncogenesis Start?
34Viral Oncogenesis and Proliferative Events in Transplantation CMV: Early arteriosclerosis, role in PTLD.Epstein Barr Virus: PTLD (B-cell), Hodgkin’s, T-cell (Asia), Burkitt’s (c-myc, P. falciparum), Cofactor in Kaposi’s?Papillomavirus: Squamous, Anogenital CancersHHV8/KSHV: Kaposi’s sarcoma, Castleman’s ds.Hepatitis B (C?): Hepatocellular carcinomaHepatitis C: Splenic, non-Hodgkin’s lymphoma (immunostimulation of villous B-lymphocytes)HTLV-1: Adult T-cell leukemia & lymphomaBK virus: Ureteric smooth muscle proliferationJC virus: PML, neuroglial tumors?
35HHV8/KSHV Risk Factors: Risk of KS increased with positive HHV8 serology (RR: )Immune Status:Risk of KS increased by CyA vs. AzaRisk of KS increased by MMF vs. AzaHHV8 activated by steroids in vitro (BCBL-1)Antilymphocyte antibodies - Relative Risk=11.3Non-neoplastic lymphoproliferative (plasmacytoid) disorders (Matsushima, Am J Surg Path 1999, 23: ) and PEL (Dotti, Leukemia 1999, 13:664-70) post-TXMany proliferative disorders
36PTLD and EBV Infection in Transplantation 28-49-fold increase in transplant recipients above age-matched controls.55% “Benign” polyclonal B-cell proliferation (“infectious mono”)30% Polyclonal or oligoclonal +/- early malignant transformation15% Extranodal, monoclonal B-cell disease (Based on Ig rearrangements or EBV genome termini)Of non-Hodgkin’s lymphomas: 87.0% arose in B-lymphocytes, 12.6% of T-cell origin, 0.4% null cell origin.
38Colitis36 year old male status post heart transplant with abdominal pain, diarrhea, no h/o bowel disease.
39EBV Colitis? Uncommon Syndrome? In Situ Hybridization: Edematous colonic mucosa, focal ulceration and granulation tissue with bizarre stromal cells; No viral cytopathic changes are identified, and immunostains for CMV, HSV-1 and HSV-2 are negative.In-situ hybridization for EBV (EBER probe) reveals occasional positive cells in the epithelium. The pattern of staining in most cells is suggestive of cytoplasmic staining by endocrine cells. THE LYMPHOID CELLS ARE NEGATIVE.
41Why is tolerance difficult to produce? It is worth recalling that the adaptive immune system (specificity and memory) was (likely) developed to protect against infectious challenges, not allografts.Successful (animal) tolerance induction has generally been achieved in mice relatively free of long-lived memory T-cells. These are usually pathogen-free mice capable of generating anergy, deletion (apoptosis), suppression (Tregs) or immune deviation (non-harmful phenotype) of naïve T-cells.
42Heterologous Immunity What is the effect of prior infectious exposures to immune responses to allografts?Virally induced alloreactive memory provides a barrier to transplantation tolerance (AB Adams et al, JCI 2003:111: ) and may autoimmunityAlloreactive T-cells are activated by viral infections (Yang H and Welsh RM JI 1986: ; Braciale TJ et al J Exp Med 1981, 153: ; Chen HD 2001, Nat Imm 2: )Allo-cross reactivity of CMV and EBVPre-existing alloreactive memory T-cells increase rejection rate (Heeger PS et al. JI 1999, 163: )
43Heterologous Immunity Viral infections alloreative memory T-cellsThese CD8+ central memory T-cells confer resistance to tolerance inductionThe level of resistance to tolerance induction is related to the number of prior infectious exposuresResistance can be adoptively transferredStudied vaccinia virus, vesicular stomatitis virus, lymphocytic choriomeningitis virus
44Longer term implications? The role of “persistent” infection in alloimmune responses is under studyDown-regulation of immune responses to virus over time (Treg CD4+ cells) also decrease anti-tumor responses (e.g., HCV, CMV, murine Friend virus)Other viruses escape immune responses by altering cytokine responses (pox & herpes) or hiding (papillomavirus)These infections may serve as models for the host response to allografts (e.g., Zinkernagel)
45Hemorrhagic Fever Viruses What’s Next?VariolaVacciniaSmallpoxEbolaMarburgAgents of BioterrorismHemorrhagic Fever VirusesUnknownThe most lethal agents known to manEbola: mortality of 88% (in some outbreaks)Marburg: 25%Lassa: 5-10%Depending who you read….To date, reservoirs of these two agents are unknown(By comparison, mortality of pneumonic plague: 40-70%)SARS
46Thank you for inviting me. I would be happy to answer questions. If I can help: