RT Journal Article
SR Electronic
T1 Quantitative flow cytometric identification of aberrant T cell clusters in erythrodermic cutaneous T cell lymphoma. Implications for staging and prognosis
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 431
OP 436
DO 10.1136/jclinpath-2013-201748
VO 67
IS 5
A1 Horna, Pedro
A1 Deaver, Darcie M
A1 Qin, Dahui
A1 Moscinski, Lynn C
A1 Sotomayor, Eduardo M
A1 Glass, L Frank
A1 Sokol, Lubomir
YR 2014
UL http://jcp.bmj.com/content/67/5/431.abstract
AB Aims Assessment of peripheral blood tumour burden for staging of cutaneous T cells lymphoma is most often accomplished by flow cytometry (FC) using various non-standarised strategies. We report the results of calculating absolute Sezary cell counts (SCCs) by FC, based on the identification of aberrant T cell clusters on a virtual 6-dimensional space and independently of the expected immunophenotype (6D-FC SCC). Methods 6D-FC SCCs were calculated on 65 peripheral blood specimens from 28 patients with erythrodermic cutaneous T cells lymphoma (stage III or IV). Comparisons were made with recommended FC strategies and correlations with overall mortality were studied. Results At first visit, 17 of 28 patients (61%) had 6D-FC SCCs meeting current criteria for Stage IV disease (≥1000 SC/μL); while only 2 patients (7%) met Stage IV criteria on other tissues. As defined by comprehensive staging using clinicomorphological criteria and 6D-FC SCCs, Stage IV disease identified a subgroup of patients with worse overall survival (p=0.0227). Residual non-aberrant CD4 T cells were markedly decreased in Stage IV disease (p=0.018). Among 65 specimens, discrepancies were observed between 6D-FC SCCs and usual FC thresholds for Stage IV disease, namely a CD4:CD8 ratio ≥10:1 (9 discrepancies, 14%), and ≥40% aberrant CD4 T cells (4 discrepancies, 6%). Surprisingly, 8 cases (12%) from 6 patients exhibited two distinctively separate clusters of aberrant CD4 T cells with different CD7 and/or CD26 expression. Conclusions Visual 6-dimensional identification of aberrant T cell clusters by FC allows for the calculation of clinically significant SCCs. Simplified gating strategies and relative quantitative values might underestimate the immunophenotypical complexity of Sezary cells.