Mobilized CD34+ cells selected as autografts in patients with primary light-chain amyloidosis: rationale and application.
BACKGROUND
Concern about tumor cell contamination in stem cell preparations has led to the use of CD34+ cell selection as a means of purging. Increasing the number of CD34+ cells per leukapheresis may help to provide an adequate dose of CD34+ cells.


METHODS
The reverse transcriptase polymerase chain reaction (RT-PCR) was employed to clone overexpressed clonotypic immunoglobulin light-chain variable region genes (Ig VL) from bone marrows of patients with primary light-chain amyloidosis (AL). Patient-specific primers were designed to evaluate stem cell collections for contamination. CD34+ cell selection was performed on components from AL patients who underwent mobilization with granulocyte-colony-stimulating factor (G-CSF) (filgrastim; 16 microg/kg/d for 4 days) and collection by large-volume leukapheresis (LVL;25L) on Days 4 and 5. The selected cells alone were transfused after patients received mephalan (200 mg/m2).


RESULTS
Contamination was found in collections from 4 to 7 patients, which provided the rationale for a subsequent trial of CD34+ cell selection. The median number of CD34+ cells per kg collected on Days 4 and 5, and in toto, was 4.0 x 10(6)(1.1-12.7), 7.9 x 10(6)(1.8-12.7), and 10.7 x 10(6)(2.9-25.4), respectively (n = 9 patients). The median yield per selection was 38 percent, with a purity of 85 percent (45-97%), and the viability of CD34+ cells averaged 96.4 +/- 3.6 percent (n = 18 selections). The median number of CD34+ cells infused was 5.9 x 10(6) per kg (2.1-10.1). In comparison with AL patients given unselected autografts, patients receiving selected CD34+ cells experienced similar reconstitution of neutrophils and platelets but slower lymphocyte recovery.


CONCLUSIONS
Patients with AL often have contamination with clonotypic cells in their blood autografts. G-CSF mobilization and LVL provide components that allow the selection of adequate doses of CD34+ cells. The use of CD34+ cells in patients with AL achieves rapid neutrophil and platelet recovery but delayed lymphocyte recovery. CD34+ cell selection is feasible in the treatment of AL, but its effectiveness in purging clonotypic cells remains to be ascertained.
Comenzo
R L
RL
Department of Pathology and Laboratory Medicine, Boston Medical Center, Boston University School of Medicine, Masschusetts 02118-2393, USA.
Michelle
D
D
LeBlanc
M
M
Wally
J
J
Zhang
Y
Y
Kica
G
G
Karandish
S
S
Arkin
C F
CF
Wright
D G
DG
Skinner
M
M
McMannis
J
J
D000328:Adult; D000686:Amyloidosis / Q000628:therapy*; D018952:Antigens, CD34 / Q000097:blood*; D002469:Cell Separation; D002999:Clone Cells; D015331:Cohort Studies; D017931:DNA Primers; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use; D006410:Hematopoiesis; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007937:Leukapheresis / Q000379:methods; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D019172:Transplantation Conditioning / Q000379:methods; D014182:Transplantation, Autologous
D018952:Antigens, CD34; D017931:DNA Primers; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D016179:Granulocyte Colony-Stimulating Factor