In vitro IL-12 treatment of peripheral blood mononuclear cells from patients with leukemia or myelodysplastic syndromes: increase in cytotoxicity and reduction in WT1 gene expression.
Interleukin-12 (IL-12) has potent antitumor activities. We examined whether IL-12 enhanced the cytotoxicity of peripheral blood mononuclear cells (PBMNC) and decreased leukemia cells in 30 patients with leukemia or myelodysplastic syndromes (MDS): 12 acute myeloid leukemia (AML) (five in complete remission (CR) and seven in non-CR); six chronic myeloid leukemia (CML); and 12 MDS (three refractory anemia (RA), eight RA with excess of blasts and one chronic myelomonocytic leukemia). PBMNC from patients and five healthy volunteers were cultured at 5 x 10(5)/ml parallel with or without 100 units/ml of IL-12 for 3 days. Cytotoxicity of PBMNC against K562 cells was assessed by flow cytometry. To quantify the amount of leukemia cells, WT1 mRNA was measured by competitive reverse transcription polymerase chain reaction (RT-PCR), since WT1 mRNA is considered as a marker of minimal residual disease (MRD) in leukemia or MDS. The cytotoxicity of non-IL-12-treated PBMNC of 30 patients was 13.4+/-9.3% at the effector to target (E:T) ratio of 20:1, and significantly lower than that of normal subjects (25.7+/-8.4%). The cytotoxicity increased to 30.6+/-17.9% in the IL-12-treated PBMNC. WT1 mRNA in PBMNC of five healthy volunteers was less than 10(3) copies/microg of total RNA. Following the 3-day IL-12 treatment, mean WT1 mRNA of PBMNC was reduced from 10(4.8) to 10(4.2) copies/microg of total RNA in six CML patients, from 10(5.4) to 10(4.8) copies/microg in 12 MDS patients and from 10(5.0) to 10(4.2) copies/microg in five AML patients in CR, but not reduced in five of seven AML in non-CR. These results showed that IL-12 significantly enhanced PBMNC cytotoxicity and decreased the quantity of leukemia cells in PBMNC of most patients with MDS, CML and AML in CR. IL-12 might be of considerable benefit in the elimination of MRD in patients with hematological malignancies.
Pan
L
L
Department of Medicine III, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Ohnishi
K
K
Zhang
W J
WJ
Yoshida
H
H
Maksumova
L
L
Muratkhodjaev
F
F
Shigeno
K
K
Nakamura
S
S
Luo
J M
JM
Hao
H L
HL
Fujisawa
S
S
Naito
K
K
Shinjo
K
K
Takeshita
A
A
Ohno
R
R
D000328:Adult; D000368:Aged; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology* / Q000627:therapeutic use; D020014:K562 Cells; D007938:Leukemia / Q000097:blood / Q000235:genetics* / Q000473:pathology; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000097:blood / Q000235:genetics* / Q000473:pathology; D018365:Neoplasm, Residual / Q000188:drug therapy / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics*; D025721:WT1 Proteins
D004268:DNA-Binding Proteins; D007376:Interleukin-2; D012333:RNA, Messenger; D014157:Transcription Factors; D025721:WT1 Proteins