Serum levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and pentraxin 3 (PTX3) as markers of infection in febrile patients with systemic lupus erythematosus.

OBJECTIVE

To investigate the role of sTREM-1 and PTX3 as markers of infection in febrile patients with SLE.

METHODS

In febrile (body temperature > or =38 degrees C) patients with SLE, blood samples of day 0, 1, 2, and 14 after presentation were drawn and relevant clinical data were collected. The patients were allocated to an infection group (n=19) or disease flare group (n=14). Serum levels of sTREM-1 and PTX3 were measured by ELISA using the serum samples of SLE patients and age- and sex-matched healthy controls (n=31).

RESULTS

A total of 33 febrile episodes occurred in 32 SLE patients (19 infections, 14 flares) were studied. sTREM-1 levels on day 0 were significantly higher in the infection group than in the flare group (109.9 pg/ml (median) vs. 48.0 pg/ml, p=0.002), but PTX3 levels were similar in these two groups. The difference of sTREM-1 levels between infection group and flare group was persistent on day 1 and 2 (day 1, p=0.007; day 2, p=0.034). The highest diagnostic value (sensitivity=1.0, specificity=0.664) of sTREM-1 was obtained at the threshold value of 53.2 pg/mL.

CONCLUSION

Serum sTREM-1 levels were significantly higher in the infection group than in the flare group of febrile SLE patients. Our findings suggest that serum sTREM-1 levels could be used to determine whether SLE patients have contracted an infection.