Modern - Blog Science Connections

Haematology and Blood Transfusion Vol. 26
Modern Trends in Human Leukemia IV
Edited by Neth, Gallo, Graf, Mannweiler, Winkler
© Springer-Verlag Berlin Heidelberg 1981
Quantitation of Chemotherapy-Induced Cytoreduction in Acute
Leukemia*
W. Hiddemann, M. Andreeff, and B. D. Clarkson
A. Introduction
In acute leukemia response to chemotherapy is
usually assessed by relative changes of the
percentage of leukemic blasts on bone marrow
smears. In contrast to quantitative evaluations
of cell numbers in peripheral blood which yield
a high accuracy, especially since the introducti
on of electronic equipment, similar approaches
have not been available for bone marrow
aspirates due to its variable cell and volume
composition of blood and bone marrow (bm).
We here report first results of a newly
developed technique which allows one to
accurately quantify the absolute number of
cells per mm 3 bm. This parameter was used to
measure treatment-induced cytoreduction rates
during induction therapy of acute non-Iymphocytic
leukemia (ANLL) and was also applied
to a phase II study of high dose thymidine
(TdR) therapy in end stage acute leukemias
and lymphomas.
B. Materials and Methods
The principle of the method is as folIows: Cell kinetic
differences between pure bm obtained by J amshidi
biopsy and bm aspirate and blood as measured by
flow cytometry (Andreeff et al. 1980; Traganos et al.
1977) are used to identify the proportion of contaminating
blood cellsin bm aspirates, wh ich subsequently
permits one to calculate the remaining proportion
of pure bm cells per mm 3 aspirate. Blood valurne
contamination is determined by the ratio of red cell
hematocrits in aspirate and blood, as distribution
studies of radioactive labeled erythrocytes have
shown that mature red cells circulate exclusively
* Supported by grants DFG Hi 288/1, ACS-CH
154, NCI-CA05826
intravascularly and are not present in pure bm tissue
(Fauci 1975; Donohue et al. 1958; Holdrinet et al.
1980). The red cell hematocrit in bm aspirates,
therefore, represents the admixed peripher al blood
volume. Combining the two described procedures,
pure bm volume and bm cell number are determined
from bm aspirates, and thus the absolute number of
bm cells per mm 3 bm volume be comes quantifiable.
The additional evaluation of the proportion of
leukemic cells on biopsy cytospin preparations
provides the means to determine the number of
leukemic bm cells per mm 3 bm (Hiddemann et al.
1980).
Leukemic cell number per mm 3 bm was measured
prior to and at the 2nd and 5th day of induction
therapy for ANLL in ten previously untreated
patients. The induction regimen consisted of daunorubicin
60 mg/m 2 per day on days 1, 2, and 3 and
cytosine arabinoside started with an initial loading
dose of 25 mg IV, followed by a 5 day infusion of 200
mg/m 2 per day and 6-thioguanine 200 mg/m 2 per
day orally administered from days 1 to 5 (Arlin et al.
1979). In four patients with end stage acute leukemias
and non-Hodgkin lymphomas, therapy induced
cytoreduction was monitored during clinical phase 11
evaluation of high dose TdR. TdR was administered
by continuous infusion over 18 to 28 days in a dose of
140 to 240 g/m 2 per day (Blumenreich et al. 1980).
c. Results
I. Induction therapy 01 ANLL
In ni ne of the ten patients a total cell kill of 2.0
to 3.9 10glO of leukemic bm cells was measured
during the 5 days of therapy as shown by the
examples in Fig. 1. In all nine patients less than
5 % bl asts were found on bm examinations
1 week after completion of chemotherapy. Six
of the nine patients subsequently went into
complete remission (CR), two died in bm
aplasia, and one developed an early relapse
73