1. Figure 2 Percentage of CD19+/CD34+ cells with decreased CD81 median fluorescence intensity (MFI; <388 units) in specimens negative for minimal residual disease (A) and specimens positive for residual precursor B-cell acute lymphoblastic leukemia (B). In A, only 1 of 139 specimens (<1%) had more than 10% CD81-dim cells. In B, 113 (85.0%) of 133 specimens had more than 10% CD81-dim cells. Of the remaining 20 specimens, 3 showed a discrete population of aberrant CD81-dim blasts (asterisks). Overall, 116 (87.2%) of 133 specimens with residual leukemia showed aberrantly decreased CD81 expression.
From: Aberrant Underexpression of CD81 in Precursor B-Cell Acute Lymphoblastic LeukemiaUtility in Detection of Minimal Residual Disease by Flow Cytometry
Am J Clin Pathol. 2015;132(5): doi: /AJCP02RPVOKTNWEC
Am J Clin Pathol | © American Society for Clinical Pathology

2. Image 2 CD81 expression by normal B-cell subsets (A and B) and a typical case of precursor B-cell acute lymphoblastic leukemia (pre-B-ALL) (C). Shown are total CD19+ cells with low side scatter. In A and B, CD10+/CD34+ immature hematogones (red) and more mature CD10+/CD34− hematogones (green) are CD81-bright. Mature B cells (blue) show moderate CD81 expression. Many pre-B-ALL blasts show decreased CD81 expression (C). APC, allophycocyanin; Cy5.5, cyanine 5.5; FITC, fluorescein isothiocyanate; PE, phycoerythrin; PerCP, peridinin chlorophyll protein.
From: Aberrant Underexpression of CD81 in Precursor B-Cell Acute Lymphoblastic LeukemiaUtility in Detection of Minimal Residual Disease by Flow Cytometry
Am J Clin Pathol. 2015;132(5): doi: /AJCP02RPVOKTNWEC
Am J Clin Pathol | © American Society for Clinical Pathology

3. Figure 1 CD81 median fluorescence intensity (MFI) of benign hematogones (12 cases) vs leukemic lymphoblasts (98 cases). The CD81 MFI was significantly lower for leukemic cells (647) than for hematogones (1,460; P = .0034).
From: Aberrant Underexpression of CD81 in Precursor B-Cell Acute Lymphoblastic LeukemiaUtility in Detection of Minimal Residual Disease by Flow Cytometry
Am J Clin Pathol. 2015;132(5): doi: /AJCP02RPVOKTNWEC
Am J Clin Pathol | © American Society for Clinical Pathology

4. Image 1 CD81 expression by normal bone marrow cell subsets
Image 1 CD81 expression by normal bone marrow cell subsets. The hematogones (red) are located in the blast gate with dim CD45 expression and low SSC (A). Hematogones show the brightest CD81 expression among all subsets (B). Also shown are myeloblasts (orange), lymphocytes (blue), monocytes (cyan), granulocytes (green), and erythrocytes (gray). PE, phycoerythrin; PerCP, peridinin chlorophyll protein; SSC, side scatter.
From: Aberrant Underexpression of CD81 in Precursor B-Cell Acute Lymphoblastic LeukemiaUtility in Detection of Minimal Residual Disease by Flow Cytometry
Am J Clin Pathol. 2015;132(5): doi: /AJCP02RPVOKTNWEC
Am J Clin Pathol | © American Society for Clinical Pathology

5. Figure 3 CD81 median fluorescence intensity (MFI) in 6 representative cases of precursor B-cell acute lymphoblastic leukemia at diagnosis and at 1 or more follow-up time points during and/or after chemotherapy. All 6 cases had blasts with aberrantly dim CD81 expression at diagnosis, and in these cases, blasts remained aberrantly CD81-dim in all specimens following chemotherapy.
From: Aberrant Underexpression of CD81 in Precursor B-Cell Acute Lymphoblastic LeukemiaUtility in Detection of Minimal Residual Disease by Flow Cytometry
Am J Clin Pathol. 2015;132(5): doi: /AJCP02RPVOKTNWEC
Am J Clin Pathol | © American Society for Clinical Pathology

6. Image 3 CD81 expression by CD19+/CD34+ cells in follow-up specimens from patients with a history of precursor B-cell acute lymphoblastic leukemia (pre-B-ALL). A threshold of 388 fluorescence units for CD81-PE is shown, and the percentage of CD19+/CD34+ cells with decreased CD81 is indicated on each plot. In a specimen negative for minimal residual disease (A), the benign immature hematogones are CD81-bright (median fluorescence intensity [MFI], 1,231). In specimens positive for residual pre-B-ALL (B–F), total CD19+/CD34+ cells show a range of CD81 MFI, as follows: B, 302; C, 2,696; D, 771; E, 1,145; and F, 87. E contains a small leukemic blast population (0.09% of total analyzed cells), forming a discrete cluster in a background of hematogones. F is from the same patient, 6 months later in overt relapse. Cy5.5, cyanine 5.5; PE, phycoerythrin; PerCP, peridinin chlorophyll protein.
From: Aberrant Underexpression of CD81 in Precursor B-Cell Acute Lymphoblastic LeukemiaUtility in Detection of Minimal Residual Disease by Flow Cytometry
Am J Clin Pathol. 2015;132(5): doi: /AJCP02RPVOKTNWEC
Am J Clin Pathol | © American Society for Clinical Pathology