Introduction:
Lenalidomide is an effective therapy of POEMS syndrome. However, there is concern that exposure to lenalidomide may reduce the efficiency of blood cell collection in persons who may eventually receive an autotransplant. We studied the impact of lenalidomide therapy on subsequent blood cell mobilization and collection including frequency of blood CD34+ cells and CXCR4 expression before and after mobilization with cyclophosphamide and granulocyte-colony stimulating factor (G-CSF).

Material and methods:
Forty-three subjects with POEMS were assigned to receive lenalidomide and dexamethasone for 2–4 28 d cycles (n = 19) or no therapy (n = 24). All subjects then received cyclophosphamide and G-CSF. Neither cohort had substantial numbers of blood CD34+ cells before mobilization.

Results:
Mobilization increased blood CD34+ frequency in lenalidomide-treated subjects and controls similarly (0.25% (95% confidence interval (CI): 0.03–1.39% vs. 0.32%, 0.04–1.47%), p = 0.472). Increases in blood CD34+ numbers were also similar (10 × 106/l) (5–77 × 106/l) vs. 14 × 106/l (6–101 × 106/l), p = 0.312). Mean CXCR4 fluorescence intensity on bone marrow cells from controls decreased from 58 ±34 (mean ± SD) to 31 ±16 after mobilization (p = NS). In contrast, mean CXCR4 intensity on bone marrow cells in lenalidomide-treated subjects increased from 55 ±43 to 89 ±40 (p = 0.017, comparing the deviation between two groups). Median numbers of CD34+ cells collected in lenalidomide-treated subjects and controls were 2.3 × 106/kg (0.6–6.8 × 106/kg) and 2.8106/kg (1.0–8.9 × 106/kg; p = 0.521).

Conclusions:
Brief lenalidomide treatment for POEMS did not reduce numbers of CD34+ blood cells collected but increased CXCR4 expression on bone marrow CD34+ cells.