BACKGROUND: The extraction of RNA from leukocytes for reverse transcription-PCR (RT-PCR) is time-consuming and contributes to variation in analysis of the Philadelphia (Ph1) chromosome of @entity1860 ( @entity1860 ) by RT-PCR. To detect residual @entity1860 after bone marrow transplantation, mRNA from at least 10(5) leukocytes should be analyzed, but the RNase activity of the cells precludes simple leukocytes lysis as an alternative to RNA extraction. We sought to identify the main source of RNase activity of leukocytes. METHODS: We used a three-step chromatographic process and @entity535 sequence analysis. We selected eosinophil-free granulocytes by using a biotinylated @entity4071 antibody and selected mononuclear cells by fractionating the leukocytes with a Ficoll-Paque(R) density gradient. RESULTS: Chromatography and @entity535 sequencing identified @entity14335 ( @entity14335 ) as the main source of leukocyte RNase. Depletion of eosinophils reduced the @entity14335 content of cell lysates by approximately 90%, allowing a signal from a lysate of 50 K562 Ph1-positive cells mixed with 10(5) @entity4071 (+) granulocytes that was equivalent to 77% of the signal in the absence of leukocytes. A similar lysate with mononuclear cells gave a signal equivalent to 53% of that without mononuclear cells. RNA extraction gave a signal equivalent to only 24% of the leukocyte-free control. CONCLUSION: The depletion of eosinophils during the preparation of leukocyte samples for RT-PCR efficiently reduces the risk of mRNA degradation by ribonucleases, enabling RT-PCR analysis directly from cell lysates with a better signal than can be obtained by RNA extraction.

Major interference from leukocytes in reverse transcription-PCR identified as neurotoxin ribonuclease from eosinophils: detection of residual XXXX from cell lysates by use of an eosinophil-depleted cell preparation.

@entity535 :: ('CHEBI:33704', 'Chemical') :: ['amino acid'] @entity4071 :: ('2214', 'Gene') :: ['CD16'] @entity1860 :: ('MESH:D015464', 'Disease') :: ['CML', 'chronic myelogenous leukemia'] @entity14335 :: ('6036', 'Gene') :: ['EDN', 'eosinophil-derived neurotoxin']
@entity1860 :: (MESH:D015464,Disease) :: ['chronic myelogenous leukemia']
