In EORTC-LCG AML-10 study patients with low CD34 mobilization profile showed a better outcome (Leukemia,2003,17:60-7). We hypothesized that patients with low pCD34 at the recovery period after RI therapy with de novo AML should have a better clinical outcome or vice versa and launched this prospective study. Between Jan 2002 and Oct 2004, 40 patients with AML (median age: 40 yrs, 17–60; 22M/18F) were enrolled to this study. Using flow cytometrical method CD34-expressing cells were measured in peripheral venous blood samples once WBC was between 1x10e9/L to 3x10e9/L at the recovery period after first RI therapy.

Results: The median time for estimation of pCD34 was 23 days (7–35) after RI. The pCD34 cell count was lower in patients responding to first RI therapy (12x10e6/L vs 68x10e6/L, p=0.011). We observed a weak, but statistically significant positive correlation between CD34 expression of the blasts at diagnosis and pCD34 at recovery period (p=0.048, r2:0.322). We could not show any significant negative impact of CD34 expression of the blasts at diagnosis and response to first RI (p=0.059). Only two of 8 patients not responding to the 1st RI achieved a complete remission after re-induction. The two-year probability of OS, LFS, relapse incidence and mortality rates were 47.1%, 37.2%, 55% and 42.5%, respectively (fig 1,2). If we set up a cut-off value of 18x10e6/L for pCD34, we did not observe any impact of pCD34 on relapse incidence but the mortality rate was significantly increased in patients with high CD34+ cell count (p=0.025).

Conclusion: We were able to show a positive impact of pCD34 estimations after first RI in AML patients on both remission and mortality rate. AML Patients with lower pCD34 after 1st RI tends to have a higher hematological remission rate and lower mortality. This impact of pCD34 as a predictive and prognostic marker in AML should be verified in large cohorts using multivariate analysis.

Table 1:

Distribution of risk factors at diagnosis according RI response

Variables1stCRafter1stRI (n=32 )NoCR after 1stRI (n=8 )P
*p<0.05; Abbr: NS: Non-Significant; ND: Not-Done 
pCD34 (x10e6/L) 12.4 (0–268) 68.6 (4.4–3820) 0.011* 
CD34 expr at dx 12% (0%–94%) 44% (9–89) 0.059 
Age, years 38.5 (17–57) 43 (20–60) NS 
WBC at dx (x10e9/L) 11.85 (0.7–175.0) 5.10 (2.7–114.7) 0.934 
EM involvement (Y/N) 7/25 0/8 NS 
Variables1stCRafter1stRI (n=32 )NoCR after 1stRI (n=8 )P
*p<0.05; Abbr: NS: Non-Significant; ND: Not-Done 
pCD34 (x10e6/L) 12.4 (0–268) 68.6 (4.4–3820) 0.011* 
CD34 expr at dx 12% (0%–94%) 44% (9–89) 0.059 
Age, years 38.5 (17–57) 43 (20–60) NS 
WBC at dx (x10e9/L) 11.85 (0.7–175.0) 5.10 (2.7–114.7) 0.934 
EM involvement (Y/N) 7/25 0/8 NS 
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Table 2:

The outcome of AML patients according to median pCD34 at recovery

VariablespCD34<Med 18x10e6/kg (n=20 )pCD34 ≥ Med 18x10.6/kg (n=20)p
CR1 (Y/N) after 1st RI 19/1 13/7 0.044* 
Relapse incidence 44% 54.5% NS 
Mortality rate 25% 60% 0.025* 
DFS 46.19%±12.6% 29.2%±10.4 NS 
OS 64.95%±13.2% 35.6%±11.3 NS 
VariablespCD34<Med 18x10e6/kg (n=20 )pCD34 ≥ Med 18x10.6/kg (n=20)p
CR1 (Y/N) after 1st RI 19/1 13/7 0.044* 
Relapse incidence 44% 54.5% NS 
Mortality rate 25% 60% 0.025* 
DFS 46.19%±12.6% 29.2%±10.4 NS 
OS 64.95%±13.2% 35.6%±11.3 NS 
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Topics:
cd34 antigens, prognostic marker, remission induction, suppository, disease remission, complete remission, leukemia, cell count, treatment outcome, blast cells

Author notes

Corresponding author

2005, The American Society of Hematology
2005
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