Cytopenia Associated with Abnormal T-Cell Response
Jiankun Tong, Song Lu, Neil G Haycocks, Richard Y Zhao, Sanford A Stass, Xianfeng Frank Zhao. University of Maryland School of Medicine, Baltimore, MD
Background: Cytopenia is defined as isolated anemia, leukopenia, thrombocytopenia or any of these two or three combined, and represents one of the most frustrating syndromes to both hematologists and hematopathologists. While cytopenia is a feature of various diseases including aplastic anemia (AA), paroxysmal nocturnal hemoglobinemia (PNH), myelodysplastic syndrome (MDS), T-cell large granular lymphocytic leukemia (T-LGL), and any malignancies that involve the bone marrow, not all cytopenias show bone marrow abnormalities. We have identified a subset of patients with not-well-defined cytopenia associated with abnormal T-cell clones. Thus, the current study attempts to substantiate our observation and to uncover the mysteries of this subset of cytopenias with unknown causes.
Design: To evaluate the possible correlation between cytopenias and the abnormal T cell populations, 19 patients who presented with various cytopenias but no clear causes were identified. T-cell receptor (TCR) gene rearrangement studies were performed on either bone marrows or peripheral blood in all these patients due to the clinical suspicion of T-LGL. Analysis of the bone marrow pathology, cytogenetics, and molecular study results was performed, and correlation with the clinical information of these patients was investigated.
Results: Based on the TCR gene (TCRγ and TCRρ) rearrangement results (with a cut-off of 5%), the 19 patients were categorized into two groups. Group One includes 9 patients with no clearly defined pathological diagnosis, but with a small population of monoclonal T-cells (<5%). Group Two consists of 10 patients with no clearly defined marrow abnormality, but with oligoclonal T-cells (>5%). Molecular follow up revealed that the T cells evolved from oligoclonal to monoclonal populations in several Group One patients. Clinical follow up showed that some of the Group One patients responded to steroids, suggesting a possible abnormal T-cell immune response being involved. Group Two is often associated with reactive conditions (such as HIV and Hepatitis C infections, etc.) and managed with clinical follow up and supportive care.
Conclusions: Although cytopenias with nonspecific pathological findings pose a diagnostic challenge to hematopathologists, molecular study is a useful tool in identifying such cases. Dysregulated T-cell immune response may account for the cytopenia associated with oligoclonal populations or small monoclonal population of T cells.
Wednesday, March 21, 2012 9:30 AM
Poster Session V # 200, Wednesday Morning