Academic Appointments

Research & Scholarship

Current Research and Scholarly Interests

1. Flow Cytometry of Hematopoietic Neoplasms.
2. Automated Hematology Instrumentation.
3. Wright-Giemsa Cytology of CSF and Body Fluids.
4. Blood/Bone Marrow Pathology


2016-17 Courses


All Publications

  • Low CD27 expression in plasma cell dyscrasias correlates with high-risk disease: An immunohistochemical analysis AMERICAN JOURNAL OF CLINICAL PATHOLOGY Morgan, T. K., Zhao, S., Chang, K. L., Haddix, T. L., Domanay, E., Cornbleet, P. J., Arber, D. A., Natkunam, Y. 2006; 126 (4): 545-551


    Genome-wide expression studies using complementary DNA microarrays recently suggested a number of intriguing candidate genes for distinguishing plasma cell dyscrasias. Our objective was to test select markers using immunohistochemical analysis and a tissue microarray from paraffin-embedded bone marrow core biopsy specimens obtained from 8 patients with monoclonal gammopathy of undetermined significance, 17 with plasmacytoma, 160 with multiple myeloma, and 15 with plasma cell leukemia (PCL). We immunostained serial sections for CD138, CD27, CD56, p27, Ki-67, CD3, and CD20. Each core was scored in duplicate by observers blinded to phenotype and reported as the average percentage of CD138+ cells. The Mann-Whitney U test was used to determine significance between groups. PCL showed significantly less immunostaining for CD27 (P < .01) and p27 (P < .05) compared with plasmacytoma and multiple myeloma. Low CD27 expression also was associated with plasmacytoma progression to multiple myeloma (P <.05). Our results support the hypothesis that low CD27 expression correlates with high-risk disease, including primary PCL and decreased progression-free survival in solitary plasmacytoma.

    View details for DOI 10.1309/ELGMGX81C2UTP55R

    View details for Web of Science ID 000240638900007

    View details for PubMedID 16938662

  • Clinical utility of the band count CLINICS IN LABORATORY MEDICINE Cornbleet, P. J. 2002; 22 (1): 101-?


    Enumeration of band neutrophils has a long clinical tradition as a diagnostic test for bacterial infection. Yet, the band count is a nonspecific, inaccurate, and imprecise laboratory test. Review of the literature provides little support for the clinical utility of the band count in patients greater than 3 months of age. The white blood cell count and the automated absolute neutrophil count are better diagnostic tests for adults and most children. Absolute numbers of bands are required for the Rochester criteria, a diagnostic algorithm for acutely ill, febrile children less than 3 months of age. No studies, however, assess the independent contribution of bands to the performance of the algorithm, or the use of the automated total neutrophil count as a replacement for the band count. Band counts also are required to calculate an immature to total neutrophil ratio (I:T ratio), an index widely used to aid in the diagnosis of neonatal sepsis. Studies, however, show a wide range of sensitivity and specificity for the I:T ratio, indicating variable performance. In the near future, rapid analysis of inflammatory factors, adhesion molecules, cytokines, neutrophil surface antigens, or even bacterial DNA may be superior alternative tests for the early diagnosis of sepsis.

    View details for Web of Science ID 000174935800008

    View details for PubMedID 11933571

  • Natural killer cell precursor acute lymphoma/leukemia presenting in an infant ARCHIVES OF PATHOLOGY & LABORATORY MEDICINE Natkunam, Y., Cherry, A. M., Cornbleet, P. J. 2001; 125 (3): 413-418


    Lymphoma/leukemia derived from immature natural killer (NK) cells occur most commonly in adults and are characterized by blastic cytologic features and an aggressive outcome. Predilection for extranodal sites and absence of the Epstein-Barr virus associated with mature NK cell malignancies further distinguish this entity. We present a NK precursor acute lymphoma presenting with multiple masses in an infant without circulating blasts or marrow replacement by disease. The diagnostic difficulty arose from several factors, including young age, presentation with multiple masses, blastic cytologic features mistaken for a small, round, blue cell tumor, and the absence of lineage-specific markers. The CD56+, CD34+, CD33+, MPO-, cytoplasmic CD3+, CD45-, CD7-, HLA-DR-, and TdT- immunophenotype of this neoplasm overlaps with previously reported cases of myeloid/NK precursor acute leukemia and blastic NK cell lymphoma/leukemia. This case emphasizes the need for a strong index of suspicion to recognize this rare entity and to distinguish it from solid tumors and other hematolymphoid neoplasms that occur in infancy.

    View details for Web of Science ID 000167405000023

    View details for PubMedID 11231495

  • Blastic/blastoid transformation of follicular lymphoma - Immunohistologic and molecular analyses of five cases AMERICAN JOURNAL OF SURGICAL PATHOLOGY Natkunam, Y., Warnke, R. A., Zehnder, J. L., Jones, C. D., Milatovich-Cherry, A., Cornbleet, P. J. 2000; 24 (4): 525-534


    Progression of follicular lymphoma to a higher-grade malignancy frequently heralds a poor prognosis. Clinical transformation is variably accompanied by a spectrum of histologic changes characterized by alteration in growth and cytology. Although several cytogenetic events and potential oncogenes have been documented in this progression, the underlying molecular mechanisms are largely unknown. We present five patients with an unusual histologic transformation of follicular lymphoma manifested by blastic/blastoid morphology. This transformation is histologically distinct from other types of transformation of follicular lymphoma. All five cases exhibited the t(14;18) translocation and expressed the BCL-2 protein. In addition, two of the five patients showed increased levels of the p53 protein within neoplastic cells implicating a possible role for this oncogene in blastic/blastoid transformation. The lack of BCL-1 and myeloid antigens by immunohistochemistry and flow cytometry studies served to distinguish blastic/blastoid transformation of follicular lymphoma from its morphologic mimics. This distinction is clinically important because lymphoblastic and myeloid leukemias require significantly different therapeutic modalities and show better prognosis. Moreover, the lack of Epstein-Barr virus-specific mRNA suggests that this virus is unlikely to participate in blastic/blastoid transformation of follicular lymphoma.

    View details for Web of Science ID 000086211700006

    View details for PubMedID 10757399

  • Aggressive natural killer-like T-cell malignancy with leukemic presentation following solid organ transplantation AMERICAN JOURNAL OF CLINICAL PATHOLOGY Natkunam, Y., Warnke, R. A., Zehnder, J. L., Cornbleet, P. J. 1999; 111 (5): 663-671


    NK-like T-cell malignancies are part of a spectrum of lymphoproliferative diseases that complicate immunosuppression associated with solid organ transplantation. We describe 2 patients with long-standing immunosuppression following solid organ transplantation. Both patients had systemic symptoms that included fever, myalgia, and weight loss. Organ involvement and lymphadenopathy were not initially observed. Unique to these 2 cases are the initial leukemic symptoms, which led to further characterization and identification of NK-like T-cell malignancies. Both patients exhibited an anomalous T/NK phenotype, CD56 positivity, and atypical blastic architecture of the large granular lymphocytes. Clonal rearrangement of T-cell receptor genes was detected in both patients. In 1 patient, a cytogenetic abnormality involving 8q24 was demonstrated. The disease course in both patients was aggressive, with involvement of multiple sites and rapid demise. This study emphasizes the importance of including NK-like T-cell malignancies in the differential diagnosis of lymphoproliferative disorders associated with immunosuppression and recognizing that an aggressive clinical course may follow leukemic presentation of disease.

    View details for Web of Science ID 000079920500011

    View details for PubMedID 10230357

  • IgM myeloma: Case report with immunophenotypic profile AMERICAN JOURNAL OF HEMATOLOGY Haghighi, B., YANAGIHARA, R., Cornbleet, P. J. 1998; 59 (4): 302-308


    Immunoglobulin (Ig)M myeloma is a distinct subtype of multiple myeloma (MM) displaying clinical and pathologic features of both MM and Waldenström's macroglobulinemia (WM). Although the immunophenotypic characteristics of classic MM and WM have been reported, the surface antigen expression of IgM myeloma has not been reported. We report a case of IgM myeloma and describe its immunophenotypic profile using flow cytometry. The cells showed a hybrid MM-WM phenotype, strongly expressing CD38 but lacking CD45 and DR, typical for plasma cells; however, pan-B cell antigens CD20 and FMC7 as well as weak monoclonal surface Ig also were positive, resembling B-cell lymphoproliferative malignancies. Discordant B-cell antigen expression was present, in that pan-B antigens CD19 and CD22 were absent. In addition, B-cell activation antigen CD23, early B-precursor antigen CD10, and pan-T antigen CD5 were not expressed. Although CD20 and weak surface Ig expression have been reported in MM, FMC7 positivity has not been seen. The data therefore suggest that IgM myeloma may have a unique phenotype with characteristics of both MM and WM.

    View details for Web of Science ID 000077138200006

    View details for PubMedID 9840911

  • Human granulocytic ehrlichiosis: Report of a case in Northern California CLINICAL INFECTIOUS DISEASES Gewirtz, A. S., Cornbleet, P. J., Vugia, D. J., Traver, C., Niederhuber, J., Kolbert, C. P., Persing, D. H. 1996; 23 (3): 653-654

    View details for Web of Science ID A1996VF94700049

    View details for PubMedID 8879806

  • Treatment of cutaneous T-Cell lymphoma with chimeric anti-CD4 monoclonal antibody BLOOD Knox, S., Hoppe, R. T., Maloney, D., Gibbs, I., Fowler, S., Marquez, C., Cornbleet, P. J., Levy, R. 1996; 87 (3): 893-899


    Chimeric anti-CD4 monoclonal antibody was administered intravenously as a single dose to eight patients with mycosis fungoides. The dose was escalated throughout the study between patients groups, and individual patients received 50, 100, or 200 mg per dose. Seven of eight patients responded to treatment with an average freedom from progression of 25 weeks (range, 6 to 52 weeks). The treatment was well tolerated, and there was no clinical evidence of immunosuppression. Following treatment, there was significant suppression of peripheral blood CD4 counts in all patients for 1 to 22+ weeks. Only one patient made a very low titer human antichimeric antibody response. All but two patients made primary antibody and T-cell proliferative responses to a foreign antigen administered 24 hours after antibody infusion. However, there was generally marked, but temporary suppression of T-cell proliferative responses in vitro to phytohemagglutinin (PHA), tetanus toxoid, and normal donor lymphocytes. We conclude that at the dose levels studied, this antibody (1) had clinical efficacy against mycosis fungoides; (2) was well tolerated; (3) had a low level of immunogenicity; (4) decreased T-cell proliferative responses in vitro, and (5) did not induce tolerance to a foreign antigen.

    View details for Web of Science ID A1996TT48400008

    View details for PubMedID 8562959



    Hematogones (HGs) comprise a B-lineage lymphoid precursor cell population in the bone marrow (BM) that may simulate acute lymphoblastic leukemia or lymphoma. Increased numbers of HGs have been noted in children, but few reports describe their occurrence in adults. We identified 13 adult patients with significant numbers of BM lymphoid cells with the morphologic and immunophenotypic features of HGs. Common features in these patients included (1) presence of small numbers of lymphoid cells in the BM aspirate with morphologic features of HGs; (2) absence of cytologic atypia or abnormal localization of lymphoid cells in the BM biopsy; (3) absence of abnormal morphology or CD10 (common acute lymphoblastic leukemia antigen) expression in circulating lymphocytes; (4) normal BM karyotype; (5) persistence of cytopenia(s) without apparent cause, often for a prolonged period of time; and (6) no evidence of neoplastic marrow involvement, confirmed by clinical follow-up. Flow cytometry demonstrated surface expression of CD10, CD19, a lower percentage of CD20, minimal expression of CD22, and limited but polyclonal immunoglobulin light chain. Nine patients had received previous immunosuppressive therapy or BM transplantation or both, seven for hematolymphoid neoplasia. However, four patients with cytopenias of unknown etiology had no antecedent history of malignancy or marrow suppressive therapy. These findings demonstrate the clinical, morphologic, and immunophenotypic features of HGs in adults, and emphasize the difficulty in distinguishing these cells from residual marrow blasts after chemotherapy.

    View details for Web of Science ID A1994PA50000014

    View details for PubMedID 8042590

  • Classifying segmented and band neutrophils. CAP today / College of American Pathologists Cornbleet, P. J., Novak, R. W. 1994; 8 (5): 37-41

    View details for PubMedID 10147368



    Chronic lymphocytic leukemia (CLL) and hairy cell leukemia (HCL) are differentiated B-cell leukemias with well-described clinical, morphologic, and immunologic characteristics. We encountered two patients with indolent chronic B-cell leukemia showing overlapping features of these malignancies. The patients had progressive splenomegaly, minimal lymphadenopathy, and abnormal lymphoid cells with abundant cytoplasm and villi, which were strongly positive for surface antigens CD22 and CD11c, features associated with HCL. However, blood counts showed lymphocytosis without neutropenia and monocytopenia, and the bone marrow biopsies demonstrated tightly aggregated nodules of lymphocytes. In addition, the lymphoid cells were dual positive for CD19 and CD5, displaying weak-to-moderately positive monoclonal surface immunoglobulin, findings strongly suggestive of CLL. One patient failed to respond to therapy with chlorambucil and prednisone. The second patient showed a partial response to treatment with 2-chlorodeoxyadenosine. We compare our patients with similar variants of differentiated B-cell leukemias reported in the literature, including disorders described as hairy cell variant (HCL-V) or splenic lymphoma with villous lymphocytes (SLVL).

    View details for Web of Science ID A1994PD00100004

    View details for PubMedID 7527021

  • CILIATED CELL REMNANTS IN PERITONEAL-DIALYSIS FLUID ARCHIVES OF PATHOLOGY & LABORATORY MEDICINE Mahoney, C. A., Sherwood, N., Yap, E. H., Singleton, T. P., WHITNEY, D. J., Cornbleet, P. J. 1993; 117 (2): 211-213


    Ciliocytophthoria are anucleate remnants of ciliated epithelial cells derived from the lower respiratory tract and female reproductive tract. We report a case of ciliocytophthoria found in the effluent dialysis fluid of a young woman undergoing long-term ambulatory peritoneal dialysis. Inability to identify these "organisms" initially led to an extensive search for parasitic contamination or infection of the peritoneum. After identifying these "organisms" as ciliocytophthoria, a prospective study showed that ciliated cell remnants occur frequently in the effluent dialysate of young women, but not in older women or men. With increasing use of peritoneal dialysis, laboratory personnel can expect to see ciliocytophthoria in peritoneal dialysate effluent and should recognize them as benign, normal findings in young women.

    View details for Web of Science ID A1993KK44500023

    View details for PubMedID 8427572



    The authors evaluated the Coulter STKS (Coulter Corp., Hialeah, FL) five-part differential in a tertiary-care hospital using samples with a broad range of distributional and morphologic abnormalities. Particular attention was given to the performance of the instrument-generated suspect flags that occur as an aid to identify samples with abnormal leukocytes. A morphologically abnormal, or positive, blood smear was defined by the presence of any blasts, malignant lymphoid cells, grossly dysplastic neutrophils, nucleated red blood cells (nRBC), platelet clumps, or reactive lymphocytes of more than 5%. The presence of any white blood cell-related suspect flag, except for Immature Granulocyte/Bands (i.e., Blasts, Variant Lymph, NRBC, Platelet Clumps, Review Slide, or WBC*R), was considered to be a positive instrument result. The STKS showed excellent quantitative results for the WBC differential compared with the manual differential when these "morphologic abnormalities" were absent in a 400-cell manual differential or low in numbers (< or = 5%). Specificity of these non-immature granulocyte/band suspect flags was good, with a false-positive rate of only 11.7%. Overall sensitivity in 113 samples with morphologic abnormalities was 67.3%. Sensitivity to detection of > or = 1% abnormal WBCs or > or = 1 nRBC/100 WBCs (a subset of 78 samples) was 80.8%. Sensitivity to detection of more than 5% abnormal WBCs or more than 5 nRBC/100 WBCs (a subset of 53 samples) was 84.9%. The primary deficiency was the inability of the STKS to flag samples with lymphoma cells, lymphoid blasts, or more than 5% reactive lymphocytes.

    View details for Web of Science ID A1993KG79100017

    View details for PubMedID 8422021



    The CELL-DYN 3000 (Unipath Corp., Mountain View, CA) differential was evaluated in a tertiary care hospital using samples with a broad range of distributional and morphologic abnormalities. Particular attention was directed to the performance of the instrument-generated suspect flags that occur as an aid to identify samples with abnormal leukocytes, as well as the estimates of abnormal cells that are made by the instrument. The CELL-DYN 3000 showed excellent quantitative results for the white blood cell differential compared with a 400-cell manual differential, in which morphologic abnormalities were absent or occurred in low numbers (< or = 5%). Specificity of the BLAST, VARIANT LYMPH, NRBC, WBC, or DIFF suspect flags (with the requirement that the blast estimate and variant lymphocyte estimate by the instrument be > or = 1%) was 82.6%. Sensitivity of these flags to detection of more than 5% "abnormal" leukocytes (blasts, malignant lymphoid cells, grossly dysplastic neutrophils, nucleated red blood cells, or reactive lymphocytes) or significant platelet clumping was 81.6%. The primary deficiency was the inability of the CELL-DYN 3000 to flag samples with small numbers (< or = 5%) of nucleated erythrocytes, lymphoid blasts, or hairy cells, or more than 5% reactive lymphocytes. Specificity of the IG flag (with immature granulocyte estimate > or = 3%) for immature granulocytes (metamyelocytes, myelocytes, or promyelocytes) was 94.9%. Sensitivity of the immature granulocyte flag varied from 41.7% for identifying IG > or = 1% to 100% for the three samples with immature granulocytes > or = 3%. Calculation of sensitivity and specificity to varying percentages of bands showed poor flagging performance, with many false-positive and false-negative results at all levels.

    View details for Web of Science ID A1992KB87700012

    View details for PubMedID 1462958