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.