Objective: To assess the Infliximab Infusion and its Relation on Disease Activity, Severity and Acute Phase Reactant Protein in Iraqi Patients with Ankylosing Spondylitis.

Patients and Method: Sixty (60) patients were included in this study, were diagnosed as established AS patients who were attending the rheumatology outpatient clinic of Baghdad teaching hospital, thirty (30) patients of them were on conventional treatment (steroid and/or cytotoxic drugs), while the other thirty (30) patients were on biological treatment (infliximab infusion). Mean serum level of matrix metalloproteinase-3 was statistically higher in patient group (4.42 ± 3.05 ng/ml) than control group (2.69 ± 2.57 ng/ml), and also was statistically higher in patients on conventional treatment (5.31 ± 3.16 ng/ml) than those on biological treatment (3.54 ± 2.70 ng/ml). The study shown that matrix metalloproteinase-3 was higher in patient group than control group and also was higher in patients on conventional treatment than in patients on biological treatment