Absolute Lymphocyte Count at the End of Induction as a Surrogate Marker for Minimal Residual Disease in T-cell Acute Lymphoblastic Leukemia.

The relation of absolute lymphocyte count (ALC) with minimal residual disease (MRD) in T cell - acute lymphoblastic leukemia (T-ALL) is not known. The objective of the study was to correlate ALC with MRD, steroid-response and complete remission (CR). De-novo T- ALL patients (age 1-18 y) recruited prospectively; 52 enrolled, 9 excluded, and 43 analyzed. 39 achieved CR and MRD was available for 28 patients; 23 were MRD negative. ALC did not correlate with steroid response and CR. Median (range) ALC at the end of induction was significantly higher in patients who were MRD negative compared to MRD positive [1.24 (0.12, 6.69) vs 0.62 (0.15, 0.87); P=0.03], respectively. Patients having ALC ≥700 ×109 /L were significantly more likely to be MRD negative than those with lower values (P= 0.028). Our study suggests that ALC is a favorable factor, and may act as surrogate marker for MRD.