Cellular and humoral markers of systemic inflammation in acute reactive arthritis and early rheumatoid arthritis

Objective : To compare systemic inflammation in reactive arthritis (ReA), rheumatoid arthritis (RA), and sepsis using novel markers of systemic inflammation, and to study whether they are helpful in distinguishing between ReA and RA. Methods : In 28 patients with acute ReA, 16 patients with early untreated RA, and 25 patients with blood culture-positive sepsis, phagocyte CD11b expression was measured by flow cytometry, serum procalcitonin (PCT) levels by immunoluminometric assay, and soluble E-selectin (sE-selectin) levels by enzyme-linked immunosorbent assay (ELISA). Results : Neutrophil and monocyte CD11b expression and serum levels of PCT and sE-selectin were higher in patients with sepsis than patients with ReA or RA, or in healthy subjects (all p<0.01). They were comparable in healthy subjects, ReA, and RA. Conclusion : Patients with acute ReA and early RA have normal CD11b expression levels on phagocytes and normal PCT and sE-selectin levels in serum. Elevated levels suggest possible sepsis.