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I. Criado et al.
were representative of the original MBLlo cohort for all variables analyzed, except for a significantly lower age (P=0.02) vs. those 26 individuals that could not be fol- lowed - median age of 75 (range: 48-95 years)-. These later subjects could only be re-evaluated for their death vs. alive status at the end of the study because of: i) 12/26 (46%) died before the fifth year of follow-up; ii) 2 subjects declined continuing their participation in the study; and iii) the remaining 12 cases were lost to follow-up after >5y from recruitment. Eight of 65 cases followed for >5y (12%) died afterward, making a total of 21 (26%) deaths among MBLlo cases included in OS analyses.
In all 65 individuals who were evaluated after five years, ≥1 clonal B-cell population was reliably identified in PB at follow-up. In 22/65 (34%) cases ≥2 clones were detected (vs. 32% at baseline), resulting in a total of 86 MBLlo clones detected (Table 1 and Table 2). All MBLlo clones showed an identical phenotype at both time-points (Table 2). Thus, 74/86 B-cell clones (86%) showed a classical CLL-like phe- notype and 12 (14%) were classified as non CLL-like MBL clones. At year +7, 35/74 CLL-like clones (47%) corre- sponded to monoclonal cases and the remaining 39 (53%), to 19 subjects with bi(multi)clonal CLL-like MBLlo (Table 2); in two subjects, CLL-like and non CLL-like clones
Table 1. Clinical and biological characteristics of MBLlo subjects at baseline and after follow-up (year +7).
Follow-up time (months) Male/Female*
Age, years
Leukocytosis (>10x109/L)* Lymphocytosis (>4x109/L)* N. total T cells/mL
N. CD4+ T cells/mL
N. CD8+ T cells/mL
N. CD4+/CD8+ T cells/mL
N. CD4–/CD8– T cells/mL
N. NK cells/mL
N. total B cells/mL
N. normal B cells/mL
N. clonal B cells/ mL
Subjects with ≥2 MBL clones*
All subjects (n=65) CLL-like MBLlo subjects (n=54)
Baseline Follow-up Baseline Follow-up
0 84 0 84 (61-95) (61-95)
29/36 22/32 (45%/55%) (41%/59%)
70 75 68 75 (43-84) (49-91) (43-84) (49-91) 0 2 0 2 (0%) (3%) (0%) (3%)
0 3 0 2 (0%) (5%) (0%) (4%) 1261 1448 1290 1508 (341-2428) (276-3753) (341-2428) (460-3753) 687 840 684 898 (253-1572) (184-2045) (253-1572) (227-2045) 449 491 446 479 (71-1154) (66-1742) (71-1154) (96-1742) 4.3 8.2 4.5 8.2 (0.19-38) (1.1-147) (0.55-37) (1.3-147) 56 62 58 64 (8.1-254) (1.9-407) (8.0-214) (1.9-338) 304 373 297 373 (76-1138) (87-3415) (76-1138) (89-3415) 133 155 132 150 (26-1173) (22-1218) (41-478) (28-1218) 119 116 126 140 (23-478) (21-536) (37-478) (26-536) 0.99 2.0 0.75 1.7 (0.03-1101) (0.05-1149) (0.03-66) (0.05-808) 21 22 18 19 (32%) (34%) (33%) (35%)
Non CLL-like MBL subjects (n=11)
Baseline Follow-up
0 83 (63-87)
7/4 (64%/36%)
76 83 (58-81) (65-88) 0 0 (0%) (0%)
0 1 (0%) (9%) 1111 1206 (796-1965) (276-2907) 732 629 (351-1395) (184-1995) 453 617 (237-750) (66-848) 4.3 8.2 (0.19-27) (1.1-29) 36 34 (11-254) (8.1-406) 394 372 (150-848) (178-937) 137 190 (26-1173) (22-1207) 72 45 (23-136) (21-190) 56 90 (0.62-1101) (1.3-1149) 3 3 (27%) (27%)
P
NA
NA <0.01a,b,c
NS
NS <0.01a,b 0.015a,b <0.03a,b <0.02a,b,c <0.05a,b 0.001a,b <0.01a,b 0.08b <0.001a,b NS
1200
Progression* NA 1 NA 1 NA 0 NA (to MBLhi) (2%) (2%) (0%)
Deaths* NA 8 NA 7 NA 1 NA
CLL-like or non CLL-like with ≥1 B-cell clone with different phenotypes were classified depending on the phenotype of the larger clone. Results expressed as median (range) or *as number of cases (percentage). aBaseline vs. follow-up (year +7) for all cases. bBaseline vs. follow-up (year +7) for CLL-like MBL cases. cBaseline vs. follow-up (year +7) for non CLL-like MBL cases. CLL: chronic lymphocytic leukemia; MBLhi: high-count monoclonal B-cell lymphocytosis; MBLlo: low-count monoclonal B-cell lymphocytosis; N: num- ber; NA: not applicable; NK: natural killer; NS: not statistically significantly different (P>0.05).
(12%) (13%) (9%)
haematologica | 2018; 103(7)