CD38 Expression above 20% Predicts Disease Progression in Chronic Lymphocytic Leukemia and Is a Useful Prognostic Marker Where Cytogenetic and Molecular Markers Are Not Available

The prognostic significance of CD38 expression and the cut off value has not been fully investigated. As CD38 is readily available test in patients with chronic lymphocytic leukemia (CLL), we investigated its role in prediction of disease progression when a cut off value of 20% is used. Progression free survival (PFS) was defined as the time from diagnosis to first treatment or last follow up. An electronic database search of pts with CLL who presented at St Paul’s Hospital between 1969 and 2007 was performed. Among 465 pts with CLL, 161 pts (35%) had their CD38 expression measured by flow cytometry. CD38 expression and its association with other prognostic factors such as age, Rai stage, lymphocyte count at diagnosis, gender and other immunophenotypic makers were analyzed. Out of 161 pts, positive CD38 expression (>20%) was found in 36 patients (22%). Comparing the baseline characteristics of the CLL pts with CD38+ and negative disease, we found CD38 positivity more common in male pts than in female pts (p=0.03). Also patients with CD38 positive disease tend to present with more advanced stage disease (p=0.056). Progression free survival at 2, 5 and 10y for the CD38+ CLL pts was 89%, 61% and 41% respectively compared with 95%, 81% and 62% for the CD38 negative group (p=0.03). Univariate analysis revealed the following factors as significant or marginally significant for disease progression: CD38+ (p=0.03), male gender (p=0.07), Rai stage (p<0.0001), lymphocyte count above 20 ×109/l at diagnosis (p<0.0001), CD5 expression <10% (p=0.01). On multivariate analysis, only disease stage at diagnosis (p<0.0001) and CD38 expression above 20% (p=0.04) retained significant and were predictive for disease progression. We conclude that CD38 expression above 20% at the time of diagnosis can be prognostically useful and predicts for disease progression and along with Rai staging can provide inexpensive tool to follow and monitor patients with CLL.

Table: Characteristics of patients with CLL based on CD38 ≥20% and <20%

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Progression free survival for patients with CLL based on CD38 expression, cut off level 20%.

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Progression free survival for patients with CLL based on CD38 expression, cut off level 20%.

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