Serum level of neopterin is not a marker of disease activity in treated rheumatoid arthritis patients

Neopterin has been measured in many autoimmune diseases and was reported as a marker of cellular immunity activation in rheumatoid asthritis (RA). The aim of this work was to assess serum neopterin as a marker of disease activity in treated RA patients. We measured serum level of neopterin in 120 treated RA patients and 100 age- and sex-matched controls by high-performance liquid chromatography (HPLC) method, and disease activity score was calculated in all patients by DAS28-CRP score. Significantly higher levels of neopterin were observed in RA patients (11.46 ± 3.56 nmol/L) compared to healthy controls (4.74 ± 1.98 nmol/L), P < 0.0001. Significantly higher neopterin levels were observed among male RA patients [median (IQR), 13.44 (12.65–16.21)] than female RA patients [median (IQR), 11.86 (7.91–13.44)], P <0.0001. No significant correlations between neopterin and age, age of disease onset, disease duration, or any of the disease activity parameters were found. Moreover, no significant difference regarding neopterin levels in different disease activity phases was identified. Our results indicated that neopterin is a marker of RA but not a marker of disease activity in treated RA patients.