CD177 Enhances the Detection of Myelodysplastic Syndrome by Flow Cytometry.

OBJECTIVES: Previously we demonstrated that a decreased percentage of CD177-positive granulocytes detected by flow cytometry (FCM) was associated with myelodysplastic syndrome (MDS). Here we expand on those findings to more rigorously evaluate the utility of CD177 for the detection of MDS. METHODS: Two hundred patient samples (100 MDS and 100 controls) were evaluated for granulocyte expression of CD177 and 11 other flow cytometric parameters known to be associated with MDS. RESULTS: We show that CD177, as a single analyte, is highly correlated with MDS with a receiver operating characteristic area under curve value of 0.8. CD177 expression below 30% demonstrated a sensitivity of 51% and a specificity of 94% for detecting MDS with a positive predictive value of 89.5%. In multivariate analysis of 12 MDS-associated FCM metrics, CD177 and the Ogata parameters were significant indicators of MDS, and CD177 increased sensitivity of the Ogata score by 16% (63%-79%) for predicting MDS. Finally, diagnostic criteria incorporating these parameters with a 1% blast cutoff level and CD177 resulted in a sensitivity of 90% and specificity of 91% for detecting MDS. CONCLUSIONS: The findings indicate CD177 is a useful FCM marker for MDS.

CD317 is over-expressed in B-cell chronic lymphocytic leukemia, but not B-cell acute lymphoblastic leukemia.

CD317 was first identified as a multiple myeloma-associated antigen. Here we report the expression of CD317 in normal B cells and B-cell malignancies. In normal bone marrow, CD317 demonstrates a biphasic expression pattern, with higher expression on stage 1 and stage 3 hematogones, but not on stage 2 hematogones. CD317 is over-expressed in B-cell chronic lymphocytic leukemia, and appears associated with negative CD38 expression. Moreover, CD317 is barely detectable in B-cell acute lymphoblastic leukemia. Our results suggest that CD317 expression might be of prognostic significance for B-CLL, and CD317 could be used as a new marker for minimal residual disease detection in B-ALL.

CD22 expression on blastic plasmacytoid dendritic cell neoplasms and reactivity of anti-CD22 antibodies to peripheral blood dendritic cells.

We identified CD22 expression on a blastic plasmacytoid dendritic cell (pDC) neoplasm presenting as a leukemia in a child. CD22 expression, as determined by the antibody s-HCL-1, was also noted on the neoplastic cells from three additional patients with blastic pDC tumors identified at our institution. Subsequently we determined that peripheral blood pDCs react with the s-HCL-1 antibody demonstrating that normal pDCs express CD22. Evaluation of five additional anti-CD22 antibodies indicated that staining of pDCs with these reagents was poor except for s-HCL-1. Therefore, the detection of CD22 on pDCs is best demonstrated with the use of this specific antibody clone. All anti-CD22 antibodies stained conventional DCs. We also evaluated the reactivity of the anti-CD22 antibodies with basophils and noted that the pattern of staining was similar to that seen with pDCs. The studies demonstrate that normal DCs and pDC neoplasms express CD22, and highlight clone specific differences in anti-CD22 antibody reactivity patterns on pDCs and basophils.

Bimodal cell populations are common in chronic lymphocytic leukemia but do not impact overall survival.

Flow cytometric histograms were evaluated for bimodal antigen expression on samples from 246 patients diagnosed with chronic lymphocytic leukemia (CLL) at University Hospitals of Cleveland, Cleveland, OH. Survival data were obtained, and the clinical significance of bimodality was evaluated using the Kaplan-Meier method and the log-rank test. Bimodal antigen expression was found in 107 cases (43.5%). CD38 and CD13 were the most common antigens to demonstrate bimodality at 14.5% and 12.9%, respectively, and CD20, CD11c, CD5, FMC-7, and surface immunoglobulin also were frequently bimodal. Bimodal antigen expression, the number of bimodal antigens, and bimodality of a specific antigen were not associated with decreased survival in patients with CLL, although bimodality for CD38 trended toward worse overall survival. Therefore, although bimodal antigen expression is common in CLL, the presence of bimodality does not seem to have significant prognostic importance

Platelet counting by the coulter LH 750, sysmex XE 2100, and advia 120: a comparative analysis using the RBC/platelet ratio reference method.

We compared the accuracy and precision of the impedance platelet counts generated by the Beckman Coulter LH 750 and the Sysmex XE 2100 and the optical platelet counts produced by the Advia 120 and the Sysmex XE 2100 withflow cytometric reference platelet counts. Samples analyzed had platelet counts less than 150 x 10(3)/microL (150 x 10(9)/L) with a platelet flag or less than 75 x 10(3)/microL (75 x 10(9)/L) on the Sysmex SE 9500. The 105 samples were run sequentially through each analyzer. Anti-CD41 and anti-CD61 monoclonal antibodies were used for flow cytometric determination of the reference platelet count by the RBC/platelet ratio method. The Beckman Coulter and the Sysmex impedance platelet counts showed better correlation with the reference method than the optical platelet counts by the Advia and the Sysmex. At platelet transfusion thresholds of 10 and 20 x 10(3)/microL (10 and 20 x 10(9)/L), the precision of the impedance methods was somewhat better than that of the optical methods. Current methods of optical platelet counting may not be superior to impedance platelet counts for all patient populations.