Table 3. Biological parameters and JAK2V617F status.

	All Patients	Primary myelofibrosis- fibrotic type	Prefibrotic myelofibrosis	P§	Primary myelofibrosis-fibrotic type with BM fibrosis grade 1	P§§	Primary myelofibrosis-fibrotic type with BM fibrosis grade 2 or 3	P §§§
Biological parameters
Serum LDH, U/L; median (range)	N = 464, 661 (120–3444)	N = 380, 743 (120–3444)	N = 84, 451 (149–1145)	<0.001	N = 137, 597 (156–2645)	<0.001	N = 243, 826 (120–3444)	<0.001
CD34+ cell in PB, ×106/L; median (range)	N = 276, 13.8 (0.78–1902)	N = 213, 24.6 (0.81–1902)	N = 63, 3.24 (0.78–27)	<0.001	N = 82, 17.5 (0.81–800)	<0.001	N = 131, 34.3 (0.88–1902)	<0.002
CXCR4 on CD34+ cell, %; median (range)	N = 98, 29.4 (1.7–93.2)	N = 79, 25.0 (1.7–93.2)	N = 19, 46.5 (7.1–84.6)	0.035	N = 23, 46.6 (5.1–93.2)	<0.001	N = 56, 20.9 (1.7–88.6)	0.003
Serum cholesterol, mg/dL; median (range)	N = 241, 158 (64–304)	N = 201, 148 (64–288)	N = 40, 162 (94–304)	0.028	N = 77, 163 (66–272)	NS	N = 124, 144 (64–288)	NS
Abnormal cytogenetics, n. of patients (%)	N = 148, 46 (31)	N = 110, 39 (35.4)	N = 36, 5 (13.8)	0.025	N = 53, 12 (22.6)	0.008	N = 57, 27 (47.3)	0.008

^§P value refers to the difference between prefibrotic myelofibrosis and myelofibrosis-fibrotic type;

^§§P value refers to the difference between prefibrotic myelofibrosis and myelofibrosis-fibrotic type with bone marrow (BM) fibrosis grade 1;

^§§§P value refers to the difference between myelofibrosis-fibrotic type with BM fibrosis grade 1 and with BM fibrosis grade 2 or 3; ULN = Upper limit of normal; NS = Not significant.