1. Possible Causes of Primary Sclerosing Cholangitis London 2006
Roger Chapman
John Radcliffe Hospital,
Oxford ,UK

2. Results of 30 years research in pathogenesis of PSC?
“The Scream”

3. ERCP Normal bile ducts Scleros Cholangitis

4. Liver histology in PSC “Onion skin fibrosis”
Atrophy and eventual bile duct loss.
Ludwig Stage 1 = portal hepatitis with little or no periportal inflammation and fibrosis
Ludwig Stage 4 = frank biliary cirrhosis
Cuff of inflamed fibrous tissue around bile duct
Histology staged 1–4

5. Causes of Secondary Sclerosing cholangitis
Biliary Calculi
Biliary stricture
Biliary Atresia
Bile duct malformations
Biliary infections
-Cytomegalovirus
-Cryptosporidium
-Ascariasis
-Asc cholangitis
Chemotherapy eg FUDR
Formalin treatment for Hydatid cysts

6. Etiopathogenesis of PSC?

7. Small Duct PSC Normal ERCP Abnormal Liver biopsy Three recent studies
Rarely progresses to large duct PSC (< 25% over 10 yrs)
No cases of cholangioca
Urso - no evidence of benefit
Effect on UC/dysplasia unknown
Abandon the term“pericholangitis”
Normal ERCP
Abnormal Liver biopsy

8. PSC, and Inflammatory Bowel Disease
PSC -uncommon ?
-7-9/100,000 pop 1993
-21/100,00 pop
PSC % have associated IBD in Northern Europe
PSC -occurs in 5-10% of
Total UC
-underestimate?
PSC % normal LFTs
ERCP
MRCP

9. Frequency of IBD in Pts with PSC different parts of the world
First author
country
No of pt
IBD
[%] UC
Crohn’s
Schrumpf
Norway 77 96 75 14
Broome
Sweden
305 81 72
Farrant UK
126 73 71
Wiesner US
174
Olikosany
Italy
117 54 36 10
Escorell
Spain 43 46 44 2
Kocher
India 18 50
Takikawa
Japan
192 21 20 1

10. Cancer in PSC -conclusions
Risk of hepatobiliary cancer is constant at 1.5% per year
Overall prevalence of 30 %
Cancer is now commonest mode of death in PSC
Increased risk of colonic cancer
Pancreatic cancer may also be increased
?shared colonic /hepatobiliary risk of malignancy
Mechanism is unknown cp chronic inflammation
PSC is premalignant condition

11. “PSC-IBD”
Does the IBD associated with PSC differ from UC?

12. Clinical Features of UC assoc with PSC -“PSC-UC” – Different clinical phenotype?
Male predominance [2:1] cp UC alone [1:1.1]
Total in distribution – but symptomatically mild
Rectal sparing in 23% -cp 5% of UC alone
Backwash Ileitis in 64%-cp 18% of UC alone
-backwash ileitis assoc with colon ca /dysplasia
Increased rate of pouchitis post colectomy

13. Clinical Features of UC assoc with PSC -“PSC-UC” – Different clinical phenotype?
Male predominance [2:1] cp UC alone [1:1.1]
Total in distribution – but symptomatically mild
Rectal sparing in 23% -cp 5% of UC alone
Backwash Ileitis in 64%-cp 18% of UC alone
-backwash ileitis assoc with colon ca /dysplasia
Extra colonic manifestations are different
-rheumatoid arthritis cp seroneg arthropathy,
& rare skin or eye involvement in PSC/IBD
Increased rate of pouchitis post colectomy

14. PSC-IBD Genetic differences between PSC-IBD and pan ulcerative colitis
Lower carriage of B*44 and DRB1*0103 (associated with peripheral arthritis and severe disease)
Lower carriage of TNF-1031C
(associated with erythema nodosum)

15. PSC-IBD: Conclusions PSC-IBD is characterized by
Extensive disease
Mild symptoms
High colorectal carcinoma rate
Low incidence of IBD-associated EIMS
High incidence of rheumatoid arthritis
Lower rates of extraintestinal manifestations in PSC-IBD are reflected in lower carriage rates of HLA alleles associated with these EIMs

16. Susceptibility to PSC Male gender Inflammatory bowel disease
Non cigarette smoking
Immunogenetics
-MHC genes
-Non-MHC immunoregulatory genes
Cystic fibrosis genes

17. PSC :Male Predominance !!

19. Relationship between smoking habit & appendicectomy in 170 pts with PSC*UC
Controls
pvalue
smoking
never
66%
52%
39%
<0.001
ever
34%
48%
61%
former
27%
36%
<0.05
current 7%
25%
appendicectomy no
86%
88%
87%
yes
14%
12%
13%
*Mitchell et al;GUT 2002*

20. Smoking habits in PSC with and without IBD*
PSC without IBD
Controls
never
65%
68%
37%
ever
35%
32%
63%
former
27%
current 8% 5%
26%
*Mitchell et al :Gut 2002

21. ?PSC
Appears protective!

22. Protective effect of smoking in PSC?
Powerful effect
Mechanism in PSC (as for IBD) is unknown
Theories:
- alteration in mucosal blood flow
-effect on immune system
- effect on mucus

23. Pathogenesis of PSC Hypotheses/considerations
Strong association with IBD partic UC
but the paradox:
PSC can occur many years before development of UC
PSC can occur many years after colectomy
Clinical activities of colitis and PSC not related
unlike other EIM’s
ie Skin,eyes, seronegative arthropathies

24. Pathogenesis of PSC What are the possible pathogenic mechanisms?
Non-Immune
portal bacteremia
portal endotoxemia
absorbed colonic toxins
toxic bile acids
copper accumulation/toxicity
viral infections
ischaemic damage
Immune Mediated

25. Key HLA Susceptibilty Haplotypes assoc with PSC*
Significance in PSC
B8-TNF*2-DR3*0101-DRB1*0301-DQA1*0501-DQB1* DR3
Strong association;“auto-immune haplotype”
DRB3*0101-DRB1*1301-DQA1*0103-DQB1* DR6
Strong association
DRB5*0101-DRB1*1501-DQA1*0102-DQB1* DR15
Weak association
DRB4*0103-DRB1*0401-DQA1*03-DQB1* DR4
Strong association with disease protection
*Cullen S &Chapman R: Autoimmune Reviews 2003

26. MHC Susceptibility Genes in PSC*
Complex disease –not attributable to single gene locus
3 key haplotypes associated with PSC
Responsible for 90% of all PSC pts
?common susceptibility allele for all 3
Candidate is MICA*008 (mapping on HLA Class I /Class II boundary between B8 &TNFA) : occurs in 2 of key candidate haplotypes
Could all be linkage disequilibrium
*Cullen S & Chapman R:Autoimmune Reviews 2003

27. Is PSC an Autoimmune disease? Evidence for immune dysfunction
Autoimmunity
HLA DR3 DQ2 haplotype
Autoimmune disease associations
HLA DR3 DQ2 allele frequency was 26% in PSC patients cf 16% of UC patients cf 10% of controls
25% of PSC patients have another autoimmune disease
9% of IBD patients have another autoimmune disease (Ulrike Broome group Sweden 2000)
2:1 male to female
Poor response to immunosuppression

28. Evidence for immune dysfunction
Autoantibodies found in PSC
Antibody
Prevalence
Atypical p-ANCA
33-87%
Antinuclear antibody
7-77%
Anti smooth muscle antibody
13-20%
Anti-endothelial cell antibody
35%
Anti-cardiolipin antibody
4-66%
Thyroperoxidase
7-16%
Thyroglobulin 4%
Rheumatoid factor
15%
Indicate an altered state of immune responsiveness.
No help in determining prognosis
Most - low prevalence and low titres
Atypical p-ANCA distinct staining pattern on indirect fluoroscopy
Recent paper has shown

29. Evidence for immune dysfunction
Autoantibodies
Indicate an altered state of immune responsiveness.
Low prevalence and low titres
No help in determining prognosis
Functional significance?

30. ANCA
control
ANCA positive
Alcohol fixed normal neutrophils

31. Diagnostic Role of ANCA in PSC*
Number of pts tested
% ANCA
positive
Prim Scl Chol 80
78%
Prim Bil Cirr 70
EH bile duct obstruction 21
Hepatitis C 38
Autoimmune Hep 56
42%
Ulcerative colitis 96
34%
Crohn’s disease 48 4%
*Bansi D & Chapman R Gut 1996

32. Evidence for immune dysfunction -Autoantibodies
Atypical p-ANCA
most common autoantibody found in PSC
Sensitive not specific:overlap with AIH
Antigen(s) not yet clear but may be neutrophil nuclear protein*
Limited diagnostic role
Autoantibodies to surface antigen on biliary epithelial cells – may indicate mechanism of action of antibodies in the development of clinical disease
*Terjung &Worman 2005

33. Evidence for immune dysfunction - cellular immune abnormalities
Infiltration of portal tract with lymphocytes
(monoclonal antibody
stain for CD3)
Dispute regarding circulating T-lymphocytes subsets. Fall in CD8 cells as disease progresses

34. Features of PSC cp Classical Autoimmune disease
Characteristic
Classical autoimmune disease
Primary Sclerosing Cholangitis
Age
Children and adults
Sex
Female predominance
Male Predominance
Assoc AI Disease
Yes
HLA Association(Class I & II )
Response to Immunosuppression
Usually good
Good in children
Poor in most adults

35. Role of biliary epithelial cells in the immune process?
Target of immune attack
AND
Participant in immune response
HLA expression on bile duct epithelium

36. Biliary epithelial cells
Aberrant expression of HLA Class II antigens
Allows binding of autoantigens or exogenous antigens
Normal BECS only express HLA Class I.
Present peptides to Class II restricted T-lymphocytes
Immune response

37. Bacteria,Infective Agents and PSC
Do bacteria / other infective agents gain access to portal circulation via inflamed and leaky bowel wall?

38. Bacteria/Infective agents – evidence
Portal bacteraemia
Found in 25% of colectomy patients in 1960’s
Confounded by introduction of bacteria during ERCP
Animal studies eg bacterial peptides in rectum of rats /rabbits with colitis appear in bile and initiate a small duct cholangitis

39. Bacteria - evidence Portal bacteraemia
Presence of intact colon in male patients at time of liver transplant for PSC may be a risk factor for recurrence of PSC in the allograft.
(Vera et al,Lancet 2003)
Neuberger, Birmingham Lancet 2002

40. Unifying hypothesis for pathogenesis of PSC 1 (JM Vierling)
Immunogenetically susceptible host
Bacterial antigens
Kupfer cell activation
Cytokine and chemokine secretion
Neutrophils, monocytes,lymphocytes and fibroblasts
Kuppfer cell = hepatic macrophage
JM Vierling – Cedars-Sinai Los Angeles
Concentric fibrosis around bile ducts
Ischaemia and atrophy of BEC
Cholestasis,fibrosis and biliary cirrhosis

41. The role of viruses ,unlikely bacteria,and protozoans in the pathogenesis of PSC?

42. PROTOZOANS in PSC ?PSC ?SSC
Cryptosporidium parvum implicated in AID’s &
inherited immunodeficiency syndromes (eg CD40 ligand deficiency)
Causes papillary stenosis and SC*
Evidence in PSC is lacking!
*Cello et al.1990
Adult with CD40 ligand def

43. Viruses and Etiology PSC
Virus “small piece of bad news wrapped up in a protein coat”
Sir Peter Medawer
Evidence for viral infection in PSC?

44. Candidate Viruses in PSC
Reovirus type 3 - neonatal biliary atresia
- not found in PSC/PBC tissue
Minuk et al,J Hepatol 1987
Cytomegalovirus - cholestatic hepatitis in immunocompromised pts /AID’s SC
- not confirmed in PSC
Retroviuses not confirmed in pSC

45. Candidate Viruses in PSC Ponsioen CW et al; Eur J Gastroenterol/Hepatol 2000; 14: 641-6
CONCLUSION :
No evidence of higher titres of any virus tested

46. Candidate viruses in PSC conclusion
NO consisent or reproduceable data to support role of viruses in on going pathogenesis of PSC
Possible that micro-organism need no longer to be present once pathologenetic process is activated
“hit and run phenomenon”

47. Unlikely Bacteria and PSC*
*Eur J Gastroenterol & Hepatol 2000;14:

48. Chlamydia in PSC Ponsioen CW et al; Eur J Gastroenterol/Hepatol 2000; 14: 641-6

49. Chlamydia in PSC Broad LPS assay % positive sera per immunoglobulin subclass
NB anti –LPS immunohistochemical staining neg in 14 PSC livers tested

50. Chlamydia in PSC* Conclusion
Increased seroprevalence of chlamydia –LPS compared with controls
“Chlamydia may be inciting noxious agent in PSC”
HOWEVER
NO increase or correlation with specific C.trachomatis and C.pneumoniae assays
NO chlamydial bodies found in PSC liver tissue
Further confirmatory studies needed
*Ponsioen et al Eur J GastroHepatol 2000

51. Helicobacter & PSC
Isolated from chronic cholangitis pts (in Chile); H.hepaticus and H bilis
Helicobacter sp in 50% of bile and liver from PSC patients (also PBC)
-however results not confirmed
Helicobacter hepaticus

52. Helicobacter and PSC Wadstrom,Ljungh & Willen; Gut 2001
Helicobacter pylori in PSC liver
Helicobacter species may invade human biliary tree and liver
New species of Helicobacter in cotton top tamarinds
“Helicobacter may play a role in pathogenesis of PSC and biliary malignancy”

53. Can lymphocytes from the gut explain PSC?

54. Pathogenesis of PSC :Hypothesis
Known Factors
Immune mediated
Genetic predisposition
Environmental Factors
eg nonsmoking (cp PBC)
Hypothesis
1.Bacterial Ag’s access from leaky colon
2.Shared colonic /biliary antigens attacked by T lymphocytes

55. Summary of pathogenesis of PSC
Good evidence of immune dysregulation
Circumstantial evidence of bacterial involvement
No evidence for viruses/protozoaans
Memory T lymphocytes might also be the link between the gut and the liver

56. Conclusion No convincing evidence of any
single factor in triggering or
maintaining the pathogenetic
process in PSC
Unlikely that “the Holy Grail” will
ever be found

58. Can lymphocytes from the gut explain PSC?
Assoc between PSC and IBD may be explained by adhesion molecules that direct and regulate lymphocyte trafficking to tissues
Gut lymphocytes express chemokine receptor CCR9 and alpha 4 beta 7 integrins ie post code to gut
Specific gut ligands are CCL25 and MAdCAM25
Aberrantly expressed in PSC

59. Normal Gut ligand expression
PSC:Aberrant expression on
Explanation for aberrant liver expression in PSC is unknown

60. In PSC: Homing of gut derived lymphocytes to aberrant ligand expression on liver endothelium
Chemokine receptor
integrins

61. Unifying hypothesis for pathogenesis of PSC 2 AJ Grant (Lancet 2002)
Enterohepatic circulation of lymphocytes
Active inflammation in gut produces mucosal lymphocytes
Some persist as memory T cells which could circulate through the liver
Activation of memory T cells could cause hepatic inflammation
Professor David Adams group, Birmingham – LAncet 2002
Lymphocyte homing receptors shared by liver and gut

62. Potential therapy for IBD and PSC Inhibition of adhesion molecules
monoclonalAB,natalizumab, inhibits a4subunit of a4b7 integrin
Clinical efficacy shown in Crohn’s ?PSC

63. Explains independent course of inflammation in gut and PSC
Unifying hypothesis for pathogenesis of PSC 2 AJ Grant et al (Lancet 2002)
Explains independent course of inflammation in gut and PSC
Explains occurrence of PSC after colectomy

64. Clinical Presentation of PSC Changing Spectrum
PSC circa 1979
PSC circa 2005

65. Liver histology in PSC “Onion skin fibrosis”
Atrophy and eventual bile duct loss.
Ludwig Stage 1 = portal hepatitis with little or no periportal inflammation and fibrosis
Ludwig Stage 4 = frank biliary cirrhosis
Cuff of inflamed fibrous tissue around bile duct
Histology staged 1–4

66. Direction for future work
Look more closely at HLA associations of PSC
Collaborative international efforts eg European Study Group
Careful phenotyping of disease to clarify results

67. Pathogenesis of PSC Outline of presentation
Evidence for immune dysfunction
Role of bacteria in pathogenesis
Role of viruses /unusual organisms
Unifying hypotheses for pathogenesis of PSC

68. Small Duct PSC Normal ERCP Abnormal Liver biopsy Three recent studies
Rarely progresses to large duct PSC (< 25% over 10 yrs)
No cases of cholangioca
Urso - no evidence of benefit
Effect on UC/dysplasia unknown
Abandon the term“pericholangitis”
Normal ERCP
Abnormal Liver biopsy

69. PSC phenotype “Small duct” PSC

70. Retroviruses in PSC Results/Conclusion*
HIV-1 p24 gag seropositivity in 35% PBC and in 39% PSC /biliary atresia
HIAP (human intra cisternal A-type particle) prev found in Sjogren’s salivary glands 75%PBC 39% PSC
Conclusion: HIV-1 & HIAP Ab reactivity
? autoimmune response to viral protein
? immune response to uncharacterised viral proteins crossreacting with HIV-1 And HIAP
*Mason et al Lancet 1998

71. CMV DNA
0/19 control liver
1/37 PSC liver
CMV replication reactivation
CMVNOT implicated in progression of PSC

72. “Small duct” PSC Not necessarily associated with IBD
Better long term prognosis
Just an early stage of large duct disease?
Same age of onset
Similar follow - up period
Only 20% progress to large duct disease
3 studies – largest with 33 patients
All found 12% progress to large duct disease
No cholangioca
Bjornsson Oxford and Oslo
Broome – Stockholm
Lindor - Mayo