[1228] Immunophenotypic Alterations by Flow Cytometry in Patients with Granulocyte Colony Stimulating Factor (G-CSF) Therapy May Mimic Changes Seen in Myelodysplastic Syndrome (MDS)

FA Khokhar, LJ Medeiros, JL Jorgensen. UT MD Anderson Cancer Center, Houston, TX

Background: G-CSF is often given to neutropenic patients after chemotherapy or stem cell transplant (SCT), and occasionally to patients with suspected MDS. Kussick and Wood (Arch Pathol Lab Med. 2003; 1140-1147) described immunophenotypic changes seen in G-CSF-treated patients by flow cytometry (FC). In this study, we assessed FC findings in a series of patients with known G-CSF therapy, or status/post (s/p) chemotherapy for acute myeloid leukemia (AML).
Design: Patients were identified from our institutional databases from 2006-2008. All patients had known G-CSF therapy within the last 21 days, or were s/p chemotherapy for AML with no available history of G-CSF therapy. All showed diploid cytogenetics, with morphologic features on bone marrow aspirates (BMA) not diagnostic for dysplasia or residual disease. Patients who received G-CSF included 2 SCT patients; 1 AML patient and 7 patients with other neoplasms, all s/p chemotherapy; and 1 patient with neutropenia of unknown etiology. BMA specimens were studied with a cytopenia screening panel that included CD13, CD16, CD45 and CD56. Side scatter (SSC) was measured on granulocytes, gated using CD45. FC results were compared with ranges established using 20 apparently normal bone marrows, submitted for lymphoma staging but negative for disease.
Results: Patients with known G-CSF therapy most often had an altered expression pattern of the maturation markers CD13 and CD16 (Table 1). Many also had decreased granulocyte SSC (correlating with cytoplasmic hypogranularity). A few had increased expression of CD56 on granulocytes and/or monocytes. Patients s/p chemotherapy for AML had similar findings, at a lower frequency. The patient with neutropenia of unknown etiology had a followup BMA 3.5 months later, which showed reversal of all immunophenotypic changes.

	Total patients	Altered CD13/CD16 pattern	Decreased SSC	Increased CD56+ Granulocytes	Increased CD56+ Monocytes
Known G-CSF	11	7 (64%)	5 (45%)	3 (27%)	1 (9%)
AML s/p chemotherapy	9	2 (22%)	3 (33%)	2 (22%)	1 (11%)

Conclusions: G-CSF therapy led to immunophenotypic alterations in most patients, but the pattern of changes varied from patient to patient. Some patients s/p AML chemotherapy had similar findings, perhaps due to the effects of endogenous growth factors. All of these FC findings have also been described in patients with MDS. We believe that a suggested diagnosis of MDS by FC should be made with caution in a patient with a history of recent G-CSF therapy.
Category: Hematopathology

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 194, Wednesday Afternoon