Table 1.
Patient characteristics
| Patient characteristics | n = 50 |
|---|---|
| Disease (CD/UC) | 25/25 |
| Gender (female/male) | 27/23 |
| Age (years) | 37 (range 19–80) |
| Remission/active disease | 43/7 |
| Corticosteroids (yes/no) | 7/43 |
| 5-ASA (yes/no) | 24/26 |
| AZA/6-MP | 39/11 |
| AZA dose (mg kg−1 day−1) | 2.06 (0.83–2.94) |
| 6-MP dose (mg kg−1 day−1) | 0.92 (0.33–1.62) |
| Indication for immunosuppression* | |
| Relapses >2 times per year | 7 |
| Steroid dependency | 16 |
| Chronically active disease | 24 |
| Intestinal fistulae | 1 |
| Remission maintenance | 4 |
| Postoperative prophylaxis | 2 |
| IMPDH (nmol mg−1 h−1) | 14.0 (range 7.0–21.7) |
| TPMT (U ml−1 pRBC) | 11.4 (range 5.4–15.8) |
| 6-TGN† (pmol per 8 × 108 RBC) | 154.6 (range 39.2–383.1) |
| meTIMP‡ (pmol per 8 × 108 RBC) | 1500 (range 0–11 700) |
| WBC (109 l−1) | 4.7 (range 2.7–10.2) |
| Neutrophil count (109 l−1) | 2.8 (range 1.3–9.3) |
| Lymphocyte count (109 l−1) | 1.2 (range 0.4–2.7) |
| Thrombocyte count (109 l−1) | 278 (range 148–494) |
Four patients were categorized as having more than one indication for immunosupression.
6-TGN: The lowest calibrator is 20 pmol per 8 × 108 RBC. If a result was reported as ‘traces of 6-TGN’ it was set to a concentration of 19 pmol per 8 × 108RBC. If 6-TGN was reported as ‘not detectable’, the result was set to a concentration of 0 pmol per 8 × 108RBC.
meTIMP: The lowest calibrator is 300 pmol per 8 × 108RBC. Numerical values reported <300 were accepted. When the concentration was reported as ‘traces of meTIMP’ it was set to a concentration of 200, and when reported as ‘not detectable’ it was set to a concentration of 0 pmol per 8 × 108 RBC. Reference ranges: leucocyte count 3.5–8.8 × 109 l−1; neutrophil count 1.7–8.0 × 109 l−1; lymphocyte count 1.1–4.8 × 109 l−1; thrombocyte count, females 165–387 × 109 l−1, males 145–348 × 109 l−1. CD, Crohn's disease; UC, ulcerative colitis; 5-ASA, 5-aminosalicylic acid; 6-MP, 6-mercaptopurine; IMPDH, inosine-5′-monophosphate dehydrogenase; TPMT, thiopurine S-methyltransferase; 6-TGN, 6-thioguanine nucleotide; meTIMP, 6-methylthioinosine 5′-monophosphate.