The soluble transferrin receptor reflects tumor load in chronic lymphocytic leukemia.

Background: The soluble transferrin receptor (sTfR) is a parameter of erythropoietic activity and iron deficiency. Increased levels have also been described in hematological malignancies, especially in chronic lymphocytic leukemia (CLL).

Methods: We investigated the value of sTfR in the assessment of tumor mass in 61 previously untreated CLL patients. Both hemolysis and iron deficiency were excluded. sTfR was measured nephelometrically (normal 0.81-1.75 mg/L).

Results: All Binet A patients had normal sTfR values (1.36+/-0.22 mg/L). In Binet B patients, the sTfR was increased (3.08+/-1.70 mg/L, p<0.0001) compared to Binet A patients. Binet B patients with normal sTfR had a small tumor load and no abdominal involvement. A further increase of sTfR in Binet C (3.75+/- 2.32 mg/L) was not significant compared to Binet B patients. sTfR values decreased or even normalized after successful treatment, whereas relapse or disease progression was associated with another increase of sTfR.

Conclusions: The sTfR concentration directly reflects the tumor burden in CLL. Therefore, sTfR may be of clinical value in monitoring disease activity, response to treatment and disease progression.