Neopterin in acute pancreatitis

Activation of the cellular immune system may play a role in the pathogenesis of acute pancreatitis (AP); it has recently been proposed that excessive leukocyte stimulation may lead to the most severe forms of AP. The aim of this study was to investigate serum neopterin, a useful in vivo marker of macrophage activation, in mild and severe AP and its relationship with other markers of leukocyte activation, such as interleukin-6 (IL-6) and tumor necrosis factor (TNF).

Serum levels of neopterin (mmol/ml), IL-6 (pg/ml), and TNF (pg/ml) were measured on the 1st and 7th day of hospitalization in 17 patients with severe AP and 24 with mild AP. Severe AP was defined in accordance with the Atlanta criteria: all patients have necrosis at contrast-enhanced computerized tomography scan.

Day 1: Neopterin and IL-6 levels were significantly higher in severe than in mild AP and normal controls; mild AP values were also significantly higher than in normal controls. The best neopterin cutoff level we obtained (30 mmol/ml) reached a specificity of 76% and a sensitivity of 46% in distinguishing severe from mild AP. Day 7: Neopterin was significantly higher in severe AP than in mild AP and in normal controls; no difference was seen between mild AP values and normal controls; neopterin serum levels were significantly higher on day 7 than on day 1 in severe AP but not in mild AP; in both groups of patients IL-6 was significantly higher on day 1 than on day 7. Using a neopterin cutoff level of 40 mmol/ml, we found specificity and sensitivity value of 92% in differentiating severe from mild AP. With regard to TNF values, no difference was seen on day 1 and 7 in the two groups of patients in comparison with normal controls. Neopterin serum values did not correlate with IL-6 and TNF on either day.

These results confirm the activation of the cellular immune system in AP. Initially enhanced NEOP and IL-6 serum levels reflect the severity of the disease; neopterin may be considered a reliable prognostic indicator also at a distance from AP onset because its levels increase during the 1st week of AP in patients with severe forms only.