Nucleoside diphosphate-linked moiety X-type motif 15 R139C genotypes impact 6-thioguanine nucleotide cut-off levels to predict thiopurine-induced leukopenia in Crohn’s disease patients

Table 1 Characteristics of the 411 Crohn’s disease patients included in this study

Characteristic	All patients	With leukopenia	Without leukopenia	P value
No. of subjects (%)	411	72 (17.5)	339 (82.5)	-
Gender
Male, n (%)	305 (74.0)	52 (17.0)	253 (83.0)	0.180
Female, n (%)	106 (26.0)	20 (18.9)	86 (81.1)
NUDT15 R139C
CC, n (%)	342 (80.4)	35 (10.2)	307 (89.8)	2.40 × 10-15
CT, n (%)	65 (17.9)	33 (50.2)	32 (49.8)
TT, n (%)	4 (1.7)	4 (100)	0
TPMT*3C				0.26
AA, n (%)	398 (96.8)	68 (17.1)	330 (82.9)
AG, n (%)	13 (3.2)	4 (30.8)	9 (69.2)
Age in years, median (range)	28 (12-70)	26(12-70)	27(12-60)	0.734
Medication
Azathiopurine	337 (82.0)	57 (17.3)	273 (82.7)	0.113
Mercaptopurine	74 (18.0)	14 (18.9)	60 (81.1)
Thiopurines dose, mg/kg per day, median (range)	1.7 (0.2-3.1)	1.5 (0.5-2.6)	1.7 (0.2-3.1)	0.030
CD
Ileal L1	34	6	28	0.495
Colorectal L2	21	6	15
Ileocolonic L3	292	48	244
Upper gastrointestinal L4	61	12	49
Co-medication	211	45	166	0.74
Corticosteroids	79	15	64
Thalidomide	51	13	38
Anti-TNF agent	64	13	51
5-ASA	4	0	4
Allopurinol	13	4	9

Patients carrying the nucleoside diphosphate-linked moiety X-type motif 155 R135C CT and TT genotypes were more likely to develop thiopurine-induced leukopenia (^bP < 0.01). NUDT15: Nucleoside diphosphate-linked moiety X-type motif 15; CD: Crohn’s disease.