الفهرس 
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Abstract
Progressive familial intrahepatic cholestasis (PFIC) is a group of inherited
disorders with severe cholestatic liver disease from early infancy. The natural
course of PFIC causes portal hypertension, liver failure, cirrhosis, hepatocellular
carcinoma, and extrahepatic manifestations.
Three types of PFIC have been identified. Types 1, 2 and 3 are due to
defects in genes involved in bile secretion (ATP8B1, ABCB11 and ABCB4
respectively). Each gene encodes for a protein (FIC1, BSEP and MDR3
respectively) that is involved in the transport of bile acids across the hepatocyte
membrane into the bile canaliculi. Absence or malfunction of any of the previous
proteins causes the disease to develop.
The disease typically manifests itself in the first year of life, and may present
with jaundice, irritability, growth failure, diarrhea, bleeding disorders, and/or an
enlarged liver. The hallmark feature of this disorder is severe debilitating pruritus.
There are several clinical differences in the three subtypes. PFIC1 (low-
GGT) is a systemic disease and can include problems in addition to liver disease;
pancreatitis, diarrhea, hearing problems and growth failure. PFIC2 (low-GGT)
solely involves the liver but has a more severe progressive course if untreated,
including the possible development of liver and bile duct malignancy. PFIC3 (high-
GGT) has a broad clinical spectrum. In the latter subtype, partial deficiency cause
milder effects, may include gallstones and intermittent itching and may not present
until adulthood. In complete deficiency, the effects are quite severe, and often
progress to cirrhosis and liver failure within the first few years of life.
Until recently, no specific test confirmed the diagnosis of PFIC. Typically, it
is characterized by elevated liver enzymes, elevated total and conjugated bilirubin,
abnormal bleeding times, low or normal GGT in PFIC1 and PFIC2 and high GGT in
PFIC3. Genetic testing is now available to confirm the diagnosis of PFIC.
The aim of our study was to assess the reliability of liver tissue
immunostaining in cholestatic patients and its role in discriminating PFIC from other cholestatic disorders and discriminating subtypes or PFIC from one another.
Fifty individuals were enrolled in this study, 25 patients with PFIC and 25
patients with cholestasis for causes other than PFIC. A normal kidney, liver and
placenta biopsies were included as controls for FXR, BSEP and MDR3
respectively. All patients underwent full history taking, thorough clinical examination
and the following investigations:
1. Complete blood count
2. Liver function tests (AST, ALT, GGT and ALP), Albumin, total proteins,
total bilirubin, direct bilirubin and prothrombin time)
3. Viral markers for Hepatitis B and C, and TORCH screen
4. Total serum bile acids
5. Further investigations according to the expected etiology of cholestasis
were requested
6. Abdominal ultrasound examination
7. Liver biopsy for histopathological findings (Liver biopsy was accepted
when obtained before commencing cause-specific treatment)
8. Liver tissue expression of FXR (NR1H4), BSEP (ABCB11) and MDR3
(ABCB4) protein using immunohistochemistry
The expression of positive cells in the immunostained sections was
interpreted in a qualitative method based on the presence or absence of the
immunoreaction and was expressed as positive or negative.
Data were collected, coded and processed by statistical analysis using
SPSS program version 17 and the results were put in tables and graphs.
Our results showed that:
1. PFIC and non-PFIC cholestasis groups were age and sex matched (Pvalue
> 0.05)
2. The occurrence of pruritus was significantly higher in PFIC group (28%)
than that in the non-PFIC cholestasis group (0.0%).
3. The occurrence of clay stool was significantly higher in the non-PFIC
cholestasis (56%) group than that in the PFIC group (16%).4. Clinical hepatomegaly was significantly higher in PFIC group (84%) than
that in the non-PFIC cholestasis group (56%).
5. By ultrasonography, hepatomegaly was significantly higher in PFIC group
(92%) than that in the non-PFIC cholestasis group (64%).
6. Abnormal gallbladder sonography (non-contractile or atretic) was
significantly higher in the non-PFIC cholestasis (76%) group than that in
the PFIC group (20%).
7. The mean level of serum GGT was significantly lower in PFIC group
(123.48 ± 173.97 U/l) than that in the non-PFIC cholestasis group (665.96
± 677.89 U/l). Moreover, the mean values of serum GGT level were
significantly lower in PFIC1 and PFIC2 compared to PFIC3 with the
values of 33.5 ± 20.51 U/l, 49.94 ± 27.12 U/l and 361 ± 230.28 U/l
respectively.
8. As regard liver function tests (total and direct bilirubin, albumin, AST,
ALT, ALP, PT and INR) in our study, the mean serum levels were
elevated in both groups with no significant difference between PFIC group
and non-PFIC cholestasis group.
9. AST mean levels in PFIC1, PFIC2 and PFIC3 groups were 53 ± 8.48 U/l,
437.24 ± 682.22 U/l and 231.17 ± 107.67 U/l respectively. Whilst ALT
mean levels in PFIC1, PFIC2 and PFIC3 groups were 24.5 ± 2.12 U/l,
225.71 ± 296.14 U/l and 118.83 ± 45.45 U/l respectively.
10. The mean level of serum bile acids was significantly higher in the PFIC
group (136.98 ± 92.27 μmol/l) than in the non-PFIC cholestasis group
(30.87 ± 52.08 μmol/l) with a P-value of 0.04 and at a cut-off value of 98
μmol/l had a clinical performance of 61.9% sensitivity, 100% specificity,
100% PPV, 27.3% NPV and 82.95% accuracy in discriminating between
PFIC and non-PFIC cholestasis groups.
11. There was no significant difference in the PELD score we estimated in the
PFIC and non-PFIC cholestasis groups.
12. The PELD score in PFIC1 (16.5 ± 0.71) group was significantly higher
than that in PFIC2 (11.24 ± 6.87) and PFIC3 (6.5 ± 6.4) groups.
13. The occurrence of intraductal bile plugs was significantly higher in the
non-PFIC cholestasis (44%) group than that in the PFIC group (12%).14. The occurrence of portal fibrosis score in the PFIC group was as follows:
no fibrosis (4%), fibrous expansion in some portal tracts (24%), fibrous
expansion in all portal tracts (36%), periportal or portal-portal septa with
an intact architecture (28%), bridging fibrosis with distorted architecture
(4%) and probable cirrhosis (4%).
15. The occurrence of portal fibrosis score in the non-PFIC cholestasis group
was as follows: fibrous expansion in some portal tracts (24%), fibrous
expansion in all portal tracts (24%), periportal or portal-portal septa with
an intact architecture (20%), bridging fibrosis with distorted architecture
(20%) probable cirrhosis (4%) and definite cirrhosis (8%)
16. The rarity of lobular necro-inflammation in PFIC1 (100%) compared to
PFIC2 (47.1%) and PFIC3 (83.3%) denoting the characteristic bland
cholestasis of PFIC1
17. The scarcity of giant cell transformation in PFIC1 (absent in 50%, rare in
50%) compared to higher occurrences in PFIC2 and PFIC3 (absent in
58.8% and 50%, rare in 17.6% and 16.7%, present in 23.5% and 33.3%
respectively) was found significant.
18. There was no significant difference in the negative expression of FXR in
liver tissue between PFIC (56%) and non-PFIC cholestasis (44%) groups.
19. There was no significant difference in the negative expression of FXR in
liver tissue between PFIC1 (100%), PFIC2 (58.8%) and PFIC3 (66.7%).
20. There was no significant difference in the negative expression of FXR in
liver biopsy between PFIC1 (100%) group versus PFIC2 group (58.8%).
21. Negative FXR expression in PFIC1 group versus PFIC2 group had a
sensitivity of 100%, specificity of 41.1%, PPV of 16%, NPV of 100% and
accuracy of 70.5%.
22. There was no significant difference in the negative expression of BSEP in
liver tissue between PFIC (76%) and non-PFIC cholestasis (52%) groups.
23. BSEP negative expression in liver tissue was significantly higher in PFIC2
(82.4%) compared to PFIC1 (0%) and PFIC3 (16.7%).
24. BSEP negative expression in liver tissue was significantly higher in PFIC2
group (82.4%) compared to PFIC1 group (0.0%).
25. Negative BSEP expression in PFIC2 group versus PFIC1 group had a sensitivity of 82.4%, specificity of 100%, PPV of 100%, NPV of 40% and
accuracy of 91.2%
26. MDR3 negative expression in liver tissue was significantly higher in PFIC
(64%) than in non-PFIC cholestasis (36%) groups.
27. There was no significant difference in the negative expression of MDR3 in
liver tissue between PFIC3 (83.3%), PFIC1 (100%) and PFIC2 (52.9%).
28. MDR3 negative expression in liver tissue was significantly higher in the
PFIC3 group (83.3%) compared to the non-PFIC cholestasis group
(36%).
29. Negative MDR3 expression in PFIC3 group versus non-PFIC cholestasis
group had a sensitivity of 83.3%, specificity of 64%, PPV of 35.71%, NPV
of 94.11% and accuracy of 73.65%
30. Combined negativity of liver tissue immunostaining was significantly
higher in PFIC (92%) than in non-PFIC cholestasis (44%) groups.
31. IHC negativity either isolated or combined was found in 100% of the PFIC
group whilst triple FXR, BSEP and MDR3 positive expression in liver
tissue was found in 20% of non-PFIC cholestasis group.
In conclusion, MDR3 immunostaining managed to discriminate PFIC3 from
neonatal cholestasis for causes other than PFIC. Also, BSEP immunostaining has
presented as a strong tool in differentiating low-GGT subtypes of PFIC from one
another.
IHC may also advocate the reallocation of PFIC cases from one type to the
other which confers a strong steering force towards better prognostics and
treatment modalities of PFIC. It had also endorsed the reliability of the phenotypical
diagnosis of PFIC.
As for the IHC results in the non-PFIC cholestasis group, it raised a query
regarding the molecular events similar to that of PFIC occurring in non-PFIC
cholestasis.