Limited relevance and progression of histological alterations in the liver during thioguanine therapy in inflammatory bowel disease patients

Figures & data

Table 1. Grading of histopathological characteristics.

	Grade 0	Grade 1	Grade 2	Grade 3	Grade 4
Nodularity	Absent	Focal nodularity in reticuline staining only	Diffuse nodularity in reticuline staining only	Focal or diffuse nodularity in reticuline and H&E staining	N.A.
Phlebosclerosis	Absent	<50% of portal tracts	50% of portal tracts	>50% of portal tracts	N.A.
Perisinusoidal fibrosis	Absent	1/3 of lobular area	2/3 of lobular area	Whole lobular area	N.A.
Sinusoidal dilatation	Absent	1/3 of lobular area	2/3 of lobular area	Whole lobular area	N.A.
Perivenular fibrosis	Absent	<50% of central veins	>50% of central veins	N.A.	N.A.
Periportal fibrosis	Absent	Non-septal periportal fibrosis	<50% of portal tracts with fibrous septa	>50% of portal tracts with fibrous septa	Cirrhosis
Steatosis	<5%	5%–33%	33%–66%	>66%	N.A.
Portal inflammation	Absent	Mild	Moderate	Severe	N.A.
Interface inflammation	Absent	Mild	Moderate	Severe	N.A.
Lobular inflammation	Absent	Mild	Moderate	Severe	N.A.

N.A.: not applicable.

Figure 1. Flow-chart of patients with inflammatory bowel diseases (IBD) with at least two liver biopsies prior to, at time of, or after cessation of thioguanine (TG) treatment.

Table 2. Patient and disease characteristics.

	N	%/SD/range
Total patients	25
Sex – male/female	10/15	40%/60%
Age, year	43.9	SD: 13.0
Body-mass index	25.0	SD: 5.0
IBD – CD/UC	15/10	60%/40%
IBD disease duration, year	8.7	0.0–25.6
Location/behavior/extent
CD – Ileum	5	33%
CD – Colonic	5	33%
CD – Ileocolonic	5	33%
CD – Non-stricturing, non-penetrating	6	40%
CD – Stricturing	4	27%
CD – Penetrating	5	33%
UC – Extensive	5	50%
UC – Left sided	3	30%
UC – Proctitis	2	20%
Thiopurine therapy prior to thioguanine
Azathioprine	17	68%
Mercaptopurine	2	8%
Azathioprine and mercaptopurine	6	24%
Intolerance	24	96%
Gastrointestinal		7
Fever	5
Liver injury		2
Fatigue	2
Pancreatitis		1
Arthralgia		1
Myelotoxicity		1
Rash	1
Unknown		4
Refractory	1	4%
Other previous immunomodulating drugs
Infliximab	4	16%
Methotrexate	3	12%
Cyclosporine	1	4%
Surgery
None	17	68%
Small bowel resection	7	28%
Colonic resection	1	4%

N: number; SD: standard deviation; IBD: inflammatory bowel disease; CD: Crohn’s disease; UC: ulcerative colitis.

Figure 2. Histopathological findings as observed in sequential liver biopsies obtained during thioguanine treatment. Histopathological abnormalities were graded from 0 to 3 according to the characteristics depicted in Table 1. The first and second bars represent the observed histopathological abnormalities in the first and second biopsy, respectively. No statistical significant differences between the first and second biopsy specimens were found although a trend towards statistical significance was observed for phlebosclerosis.

Figure 3. Microscopic examination of a liver biopsy with hepatic sinusoidal dilatation. Histopathology of a liver biopsy with hepatic sinusoidal dilatation characterized by widening of hepatic sinusoids in a patient with inflammatory bowel disease during thioguanine treatment (Hematoxylin-Eosin stained).

Figure 4. Microscopic examination of a liver biopsy with phlebosclerosis. Histopathology of a liver biopsy with phlebosclerosis characterized by sclerosis of the portal tract with diminished caliber of the portal vein caliber and extraportal shunt vessels in a patient with inflammatory bowel disease treated with thioguanine (Hematoxylin-Eosin stained).

Figure 5. Microscopic examination of a liver biopsy with nodular regenerative hyperplasia (NRH). Histopathology of a liver biopsy with NRH characterized by nodules of hypertrophic hepatocytes surrounded by a rim of atrophic liver plates with compression of sinusoids in a patient with inflammatory bowel disease treated with thioguanine without signs of (non-cirrhotic) portal hypertension (Hematoxylin-Eosin stained).

Table 3. Histopathological irregularities of the liver and their progression during time of TG treated IBD patients (n = 22).

	Biopsy 1	Biopsy 2	Grade increased	Grade decreased	Grade unaltered	p Value
Nodularity	4 (18%)	4 (18%)	3 (14%)	3 (14%)	16 (72%)	1.00
Phlebosclerosis	8 (36%)	15 (68%)	12 (55%)	4 (18%)	6 (27%)	.09
Perisinusoidal fibrosis	20 (91%)	20 (91%)	4 (18%)	5 (23%)	13 (59%)	1.00
Sinusoidal dilatation	15 (68%)	15 (68%)	7 (32%)	5 (23%)	10 (45%)	1.00
Perivenular fibrosis	6 (27%)	9 (41%)	6 (27%)	3 (14%)	13 (59%)	.51

Table 5. Histopathological and clinical alterations in 3 patients who ceased thioguanine due to hepatotoxicity.

	Patient 1		Patient 2		Patient 3^a
Sex	Female		Female		Female
Age, year	33		62		62
Type of IBD	Crohn’s disease		Crohn’s disease		Crohn’s disease
Duration of disease, year	6		3		2
Location	Colon		Ileum		Colon
Previous thiopurine treatment	MP		AZA and MP		MP
TG therapy duration, months	18		25		21
Time between stop TG + 2nd biopsy, months	21		17		8
Grade of:	1st biopsy	2nd biopsy	1st biopsy	2nd biopsy	1st biopsy	2nd biopsy
Nodularity	3	0	3	1	0	0
Phlebosclerosis	2	0	0	0	1	0
Perisinusoidal fibrosis	2	1	3	2	1	1
Sinusoidal dilatation	2	1	1	1	1	0
Perivenular fibrosis	1	1	1	0	0	0
Platelet count (×10^9/L)	131	251	111	176	402	596
Gamma glutamyl-transferase (U/L)	425	262	214	85	99	244
Alkaline phosphatase (U/L)	393	164	131	77	127	340
Medical imaging (ultrasound/CT-scan)	N.A.	N.A.	Normal	Normal	Normal	Normal

^aPatient three has liver test abnormalities, most likely explained by mild steatosis observed in both liver biopsies.

IBD: inflammatory bowel disease; TG: treatment; MP: mercaptopurine; AZA: azathioprine; CT: computed tomography; N.A.: not available.

Table 4. Laboratory findings at time of first and second liver biopsy.

	Biopsy 1	Biopsy 2	p Value
Hemoglobin (mmol/L)	8.3 (±1.1)	8.8 (±0.7)	.05
Platelet count (×10^9/L)	278 (±116)	265 (±134)	.36
White blood cell count (×10^9/L)	6.3 (4.4–11.3)	6.3 (3.3–9.1)	.85
Mean cellular volume (fl)	90 (±5)	91 (±6)	.26
Aspartate aminotransferase (U/L)	24 (13–78)	25 (14–52)	.67
Alanine aminotransferase (U/L)	28 (10–85)	24 (9–103)	.78
Alkaline phosphatase (U/L)	76 (43–204)	75 (56–133)	.84
Gamma glutamyl-transferase (U/L)	22 (6–126)	23 (10–216)	.36
6-thioguaninenucleotides (pmol/10^8 RBC)	414 (156–847)	342 (36–942)	.61