The role of high serum CXCL13 level in Waldenström macroglobulinemia.

PURPOSE

To explore the value of elevated CXCL13 levels in Waldenström macroglobulinemia (WM).

METHODS

We collected serum samples from 41 patients and bone marrow tissues from 14 patients with newly diagnosed symptomatic WM. Serum and bone marrow samples from patients with other indolent B-cell lymphomas and MGUS were also collected for comparison. Serum CXCL13 levels were measured by enzyme-linked immunosorbent assay, and bone marrow tissues were examined by immunohistochemistry.

RESULTS

The median serum level of CXCL13 in patients with symptomatic WM was 2483.0 (range 36.8-5644.0) pg/ml, which was significantly higher than in patients with other indolent B-cell lymphomas with monoclonal IgM (median 380.9 pg/ml, range 23.8-5518.0 pg/ml) (p = 0.01). Serum CXCL13 >3250 pg/ml and serum M-protein >38 g/l diagnosed WM with a sensitivity of 98% and specificity of 85%. Serum CXCL13 was strongly correlated with hemoglobin levels (ρ=-0.46, p = 0.002), serum M-protein (ρ=0.47, p = 0.002), and IgM levels (ρ=0.30, p = 0.05) in patients with symptomatic WM. Immunohistochemistry analysis indicated that CXCL13 and activated mast cell levels were also higher in the bone marrow of WM patients compared to patients with IgM-MGUS or other indolent B-cell lymphomas with monoclonal IgM.

CONCLUSIONS

Serum CXCL13 levels were significantly elevated in patients with WM and correlated with tumor load. Detection of serum CXCL13 may therefore be helpful in the differential diagnosis of WM.