High absolute basophil count is a powerful independent predictor of inferior overall survival in patients with primary myelofibrosis

Figures & data

Figure 1. Peripheral blood smear in PMF patient showing circulating basophile among characteristically deformed red blood cells (dacryocytes).

Figure 2. ROC curve for ABC using the survival status as classification variable.

Table 1. Patients’ characteristics stratified in two groups: ABC >0.1 (high ABC) and ≤0.1 (low ABC).

	All patients	High ABC	Low ABC	P-value
Number	58	29/58 (50%)	29/58 (50%)	–
Age	66.5 ± 9.4	67.8 ± 8.2	65.1 ± 10.4	0.266
Male gender	37/58 (63.8%)	20/29 (69%)	17/29 (58.6%)	0.412
JAK2 mutated	36/56 (64.3%)	19/27 (70.4%)	17/29 (58.6%)	0.359
CALR mutated	6/46 (13%)	3/23 (13%)	3/23 (13%)	1.000
MPL mutated	2/44 (4.5%)	1/23 (4.3%)	1/21 (4.8%)	1.000
Advanced bone marrow fibrosis	33/58 (56.9%)	19/29 (65.5%)	14/29 (48.3%)	0.185
Blast phase disease	2/58 (3.4%)	2/29 (6.9%)	0/29 (0%)	0.491
WBC	10.6 IQR (6.9–16)	15.9 IQR (9.4–29.4)	8.6 IQR (5.9–11.1)	<0 . 001
≥1% circulatory blasts	22/56 (39.3%)	17/27 (63%)	5/29 (17.2%)	<0 . 001
Hemoglobin	111.4 ± 25.5	109.6 ± 25.8	113.1 ± 25.7	0.610
RDW	20 IQR (18.3–21.4)	20.3 IQR (19.6–21.5)	19.4 IQR (17.2–20.8)	0 . 035
Platelets	327 IQR (177–527)	316 IQR (180–437.3)	331 IQR (164–574)	0.549
LDH	516 IQR (292–801)	743.5 IQR (578.3–1054.5)	348 IQR (224–533)	<0 . 001
CRP	5.9 IQR (1.9–13.4)	10.2 IQR (4–16.6)	4.7 IQR (1.4–9.8)	0.143
Constitutional symptoms	19/56 (33.9%)	13/27 (48.1%)	6/29 (20.7%)	0 . 030
Massive splenomegaly	20/54 (37%)	14/26 (53.8%)	6/28 (21.4%)	0 . 014

Note: ABC: absolute basophil count, JAK2: Janus kinase 2, CALR: calreticulin, MPL: myeloproliferative leukemia virus oncogene, WBC: white blood cells, IQR: interquartile range, RDW: red cell distribution width, LDH: lactate dehydrogenase, CRP: C reactive protein. P values <0.05 were considered statistically significant and are marked in bold.

Figure 3. There was a significant trend of increase in ABC over DIPSS categories, Jonckheere–Terpstra trend test, P = 0.002. 1 = low risk, 2 = intermediate-1 risk, 3 = intermediate-2 risk, 4 = high risk.

Figure 4. ABC >0.1 was associated with inferior overall survival, log-rank test, HR 4.79, P < 0.001.

Table 2. Overview of a Cox regression model showing that ABC >0.1, AMC >1.4 and the DIPSS have additional prognostic properties and are able to predict overall survival in PMF patients independently of each other.

Variable	HR with 95% confidence interval	P-value
ABC > 0.1	4.04 [1.24–13.18]	0 . 021
AMC > 1.4	6.18 [1.47–26.05]	0 . 013
DIPSS	2.38 [1.24–4.56]	0 . 009
Age	1.05 [0.98–1.12]	0.142
Male gender	1.47 [0.44–4.84]	0.530
WBC	1.02 [1–1.05]	0.054
Platelets < 100 × 10^9/L	1.6 [0.31–8.16]	0.571
Transfusion dependency	1.4 [0.46–4.27]	0.557

Note: ABC: absolute basophil count, AMC: absolute monocyte count, DIPSS: Dynamic International Prognostic Scoring System, WBC: white blood cells. P values <0.05 were considered statistically significant and are marked in bold.