Detection of ZAP-70 in patients with chronic lymphocytic leukemia.
OBJECTIVE
To determine the presence and prognostic significance of ZAP-70 in patients with B chronic lymphocytic leukemia (B-CLL). Expression of ZAP-70 in B-CLL is a continuum ranging from absent to high, affecting the prognostic reliability of this marker.


METHODS
32 patients with B-CLL treated from March 2006 to February 2007 were prospectively studied. Patients were stratified in two groups: those diagnosed with B-CLL within 18 months and a retrospective group diagnosed before 18 months since the beginning of this study. Patients were predominantly males (78.1%), over 60 years old (81.25%). ZAP-70 was detected on EPICX-XL flow cytometer with System II software. Directly conjugated antibodies CD19 PE, ZAP-70 FITC (clone 1E7.2) and CD2 APC were used. Leuoperm was used for permeabilization. All samples with over 20% ZAP-70/CD19 double positive B lymphocytes were considered positive.


RESULTS
ZAP-70 was absent in a group of 22 patients with B-CLL diagnosed over 18 months from the beginning of this study, while 2 out of 10 (20%) patients from the group of newly diagnosed patients were ZAP-70(+). During follow up both ZAP-70(+) cases showed worsening of their clinical status resulting to death in one patient. In borderline cases with ZAP-70(+) ranging from 10.9-19.9% there was no correlation of the level of ZAP-70 expression with disease activity or clinical scoring systems.


CONCLUSIONS
Very high percentage of ZAP-70(+) cells is a sign of poor prognosis in B-CLL. Borderline expression of ZAP-70, although more frequent, could not be successfully assigned into a risk group.
Marjanovic
G
G
Clinic of Hematology, Clinical Centre Nis, Serbia. prof.marjanovic@gmail.com
Stanojevic
I
I
Jankovic-Velickovic
Lj
Lj
Hubl
W
W
Marjanovic
V
V
D000328:Adult; D000368:Aged; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000097:blood*
D051746:ZAP-70 Protein-Tyrosine Kinase