Immunophenotypic differences between diagnosis and relapse in childhood AML: Implications for MRD monitoring

BACKGROUND

Determination of antigen expression patterns is, in addition to morphologic analysis, essential to the diagnosis of acute myeloid leukemia (AML). The present study was performed to determine (a) the degree of changes in immunophenotype and their consequences on the monitoring of minimal residual disease (MRD) in childhood AML and (b) whether certain clusters of changes in antigen expression patterns exist between diagnosis and relapse.

METHODS

Bone marrow specimens of 48 children enrolled in the German AML-BFM-93/98 (Acute Myeloid Leukemia-Berlin-Frankfurt-Munster) studies were analyzed immunologically, morphologically, and genetically at diagnosis and at first relapse.

RESULTS

The immunophenotypes by flow cytometry differed by at least one antigen between samples at presentation and relapse in 42 of 48 children (88%). More children displayed an immature phenotype at relapse (43 of 47, 91.5%, vs. 37 of 48, 77%; P = 0.05) with expression of CD34 and/or CD117. This was reflected by a gain of markers that are associated with lineage immaturity in 18 of 25 (72%) of cases, whereas the loss of such antigens was observed in 6 of 25 (24%) patients. We did not observe significant changes for lineage specific markers, with comparable occurrences of loss or gain of myeloid and lymphoid antigens in the sample pairs. Only minimal changes were seen for morphologic and genetic features.

CONCLUSION

An antigenic shift was observed in 88% of cases in this study. The antibody panels used for MRD monitoring in childhood AML should therefore not be restricted to the immunophenotype detected at presentation but should include in particular markers of lineage immaturity. The clinical observation of a shift toward a more immature phenotype of the myeloblasts is consistent with the model of a clonal evolution of a leukemic stem cell.

AIDS-related B-cell lymphoma (ARL): correlation of prognosis with differentiation profiles assessed by immunophenotyping

This study was undertaken to analyze the differentiation profiles assessed by immunophenotyping in AIDS-related B-cell lymphoma (ARL) and their relation to the clinical course. Paraffin-embedded sections of 89 ARL cases during 1989 to 2004 were stained immunohistochemically with antibodies to CD3, CD10, CD20, CD38, CD138/Syndecan-1 (Syn-1), multiple myeloma-1/interferon regulatory factor-4 (MUM1/IRF4), B-cell lymphoma protein-2 (BCL-2), BCL-6, latent membrane protein-1 (LMP-1), and Ki-67. Expression of CD10 and CD20 were associated with better overall survival (OS; P = .009 and P = .04, respectively). Expression of CD20 was associated with longer disease-free survival (DFS; P = .03), whereas expression of CD138/Syn-1 was associated with shorter DFS (P = .03). OS and DFS were worse in patients with immunophenotypic profiles related to post-germinal center (GC) differentiation (BCL-6 and CD10 negative, MUM1/IRF4 and/or CD138/Syn-1 positive) when compared with GC differentiation (P = .01). When controlled for age-adjusted International Prognostic Index (IPI), prior AIDS-defining illness (ADI), and year of ARL diagnosis, a post-GC differentiation remained significantly associated with poor OS and DFS. Expression of CD10 was associated with a preserved immunocompetence, whereas CD20 was less frequent in patients developing ARL while on highly active antiretroviral therapy (P = .04). In summary, lack of CD20 or CD10 expression and a post-germinal center signature are associated with a worse prognosis in ARL.

Abnormalities of CD4 T cell subpopulations in ANCA-associated vasculitis

In patients with ANCA-associated vasculitis (AAV), CD25 expression is increased on circulating T cells. Although in animal experiments the role of CD4(+) CD25(+) T-regulatory-cells (T(reg)) in protection against autoimmunity is well established, the role of these cells in AAV is unknown. To investigate the hypothesis that an increased expression of CD25 on T cells is related to persistent T cell activation and not to disturbances in T(reg) cells in AAV (34 patients, six of them after renal transplantation), we investigated CD25 expression in different subpopulations of CD4(+) cells and FOXP3 mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). In addition, T cell proliferation and cytokine secretion after stimulation with anti-CD3 and anti-CD28 and intracellular cytokine production after stimulation with phorbol myristate acetate (PMA)-ionomycin was determined. Controls were non-vasculitic renal transplant patients (n = 9) and healthy controls (HC) (n = 13). In AAV the total number of lymphocytes, CD4(+) lymphocytes and the percentage of naive T cells are lower than in HC and RTX. An increased percentage of CD25(+) cells was found in AAV and AAV/RTX, irrespective of disease activity, but not in HC or RTX. This was confined to the naive (CD4(+) CD45RB(high)) population only. FOXP3 mRNA expression in CD4(+) T cells did not differ between AAV patients and healthy controls. In vitro T cell proliferation was enhanced in AAV patients compared to HC (P < 0.01). PBMC of AAV patients produced significantly less interleukin (IL)-10 and interferon (IFN)-gamma after anti-CD3/CD28 stimulation. The percentage of IL-10 and IL-12, but not IFN-gamma, IL-4 or tumour necrosis factor (TNF)-alpha-producing cells was significantly higher in patients compared to HC. These findings were confined to the memory population of CD4(+) cells. We conclude that AAV patients are lymphopenic and have low numbers of CD4(+) T cells, which seem to be in a persistent state of activation.

Absolute CD4 T-Cell Counting in Resource-Poor Settings

Flow cytometry is an accurate but expensive method to determine absolute CD4 cell counts. We compared different methods to measure absolute CD4 counts in blood samples from HIV-infected and uninfected subjects using a research/clinical flow cytometer (FACScan); a dedicated clinical instrument (FACSCount); and a volumetric, mobile, open-system flow cytometer equipped with 3 fluorescence and 2 light scatter detectors (Cyflow SL blue). The FACScan and Cyflow were used as single-platform instruments, but they differ in running cost, which is a central factor for resource-poor settings. Direct volumetric and bead-based CD4 measurements on the Cyflow were compared with 2 bead-based single-platform CD4 measurements on the FACSCount and on FACScan (TruCount) in "Le Dantec" Hospital, Dakar, Senegal, using whole blood samples from 102 HIV+ and 28 HIV- subjects. The agreement between the various measurement methods was evaluated by Bland-Altman analysis. Volumetric CD4 measurements on the Cyflow using a no-lyse-no-wash (NLNW) procedure and a lyse-no-wash (LNW) procedure correlated well with each other (R2 = 0.98) and with CD4 measurements on the FACSCount (R2 = 0.97) and FACScan (R2 = 0.97), respectively. Red blood cell lysis had no negative effect on the accuracy of absolute CD4 counting on the Cyflow. An excellent correlation was observed between bead-based CD4 measurements on the Cyflow and CD4 measurements on the FACSCount (R2 = 0.99) and FACScan (R2 = 0.99). Rigid internal and external quality control monitoring and adequate training of technicians were considered essential to generate accurate volumetric CD4 measurements on the Cyflow.

C-kit receptor (CD117) expression on plasma cells in monoclonal gammopathies

The surface expression of CD117 antigen (c-kit) on plasma cells from 158 multiple myeloma (MM), 12 plasma cell leukemia (PCL), 7 MGUS, 7 IgM lymphoplasmacytic lymphoma patients and 10 healthy subjects has been analyzed by flow cytometry using triple staining with the monoclonal antibodies CD138, CD117 and CD38. The antigen expression intensity was calculated as relative fluorescence intensity (RFI) and for direct quantitative analysis the QuantiBRITE test (Becton Dickinson) was applied. Antibody bounding capacity (ABC) was calculated using QuantiCALC software. CD117 antigen was present in 49/158 MM, 5/12 PCL and 5/7 MGUS patients. The RFI values ranged from 0.2 to 20.2 in particular MM patients (mean: 11.0+/-5.3; median 11.5) while the number of CD117 binding sites (ABC) on MM plasma cells ranged from 637 to 6217 (mean: 3029+/-1568; median 2946) (r=0.8328). In responsive to chemotherapy c-kit positive MM patients the percentage of CD117+ plasma cells in the bone marrow decreased significantly while in c-kit negative MM patients the percentage of CD117+ cells in bone marrow did not change and remained in the normal limits. When comparing the clinical and biological disease characteristics (monoclonal protein isotype, albumin, beta2-microglobulin, lactate dehydrogenase, stage of disease, response to chemotherapy, survival time) of c-kit positive and c-kit negative cases, no significant differences were found. In CD117 positive PCL cases expression of CD117 was detected in bone marrow plasma cells as well as in peripheral blood plasma cells. Normal plasma cells and those in IgM lymphoplasmacytic lymphoma did not show reactivity for the CD117 antigen. We conclude that it may be rationale to consider usefulness of therapy with tyrosine kinase inhibitors in the management of c-kit positive plasma cell proliferations. In one third of MM and PCL patients c-kit antigen could be considered as a "tumor associated marker" and together with CD38 and CD138 it may be of value for the identification of the malignant clone in minimal residual disease as it was first suggested by Spanish authors.

The development of methods for immunophenotypic and lymphocyte function analyzes for assessment of Southern sea otter (Enhydra lutris nereis) health

The Southern sea otter (Enhydra lutris nereis) is listed as threatened under the Endangered Species Act. The population began a pattern of slow decline in 1995. The decline was attributed to high adult mortality rates with infectious disease being the major cause of death. Multiple pathogens were implicated in these deaths including opportunistic pathogens such as Coccidiodes immitis and Toxoplasma sp. These findings suggested that the immunological health of mature animals in this population might be compromised. The primary goal of this study was to establish techniques for assessing phenotypic and functional baseline data for peripheral blood mononuclear cells (PBMC) in free-ranging sea otters. Standard total and differential white blood cell counts were augmented by emumeration of T and B lymphocyte subsets. Lymphocyte function was determined by both mitogen-induced proliferation and expression of IL-2 receptors. In addition to establishing normal ranges for adult animals, age-related changes were identified in B lymphocyte numbers and cell-surface density of major histocompatability complex class II (MHC II) proteins. The predominant lymphocyte subpopulation in Southern sea otters is the T lymphocyte. Substantial variation among individual animals was observed within the B lymphocyte population both in cell number and density of MHC II expression. Pups had greater numbers of T and B lymphocyte, as well as, greater MHC II expression on B lymphocytes than adults. Mitogen-induced proliferation of peripheral blood mononuclear cells (PBMC) was variable among individual animals with no significant difference in cell response between age class and gender. Concanavalin (ConA) was a more effective mitogen in stimulating proliferation and interleukin (IL)-2 receptor expression than pokeweed. This data can be used to augment routine hematology profiles and aid in the identification of animals with immunologic perturbations.

[Sensitivity and specificity analysis of the lineage related antibodies in acute leukemia immunophenotyping by flow cytometry]

To evaluate the sensitivity and specificity analysis of the lineage related antibodies in acute leukemia immunophenotyping by flow cytometry (FCM), immunophenotyping in 184 patients with acute leukemia was performed by FCM analysis. The results showed that in the lineage-related antibodies of acute myelocytic leukemia (AML), the sensitivity of CD13 and CD33 was higher (95.5% and 91.2%, respectively), the specificity of them was deficient (72.5% and 62.2%, respectively); the sensitivity of MPO was low (69.1%), but the specificity was high (100%); the sensitivity and specificity of CD117 were high (88.2% and 100%, respectively); the sensitivity of CD14 and CD15 was low (18.4% and 27.2%, respectively); the specificity of CD14 with monocytes was high. As the lineage-related antibodies of B-lineage ALL were concerned, CD19 showed high sensitivity and low specificity (100% vs 83.4%); the sensitivity and specificity of CD79a (96.4% vs 100%) and CD22 (100% vs 100%) were high; the sensitivity and specificity of CD10 (53.6% vs 82.5%) and CD20 (70.4% vs 87.5%) were low. In T-lineage ALL, the specificity of CD3 was high (97.5%), but the sensitivity was below the mark (80.0%); the sensitivity of CD7 was high (100%), but the specificity was low (77.9%); while the sensitivity and specificity of CD5, CD2 and CD1a were all deficient. In conclusion, the sensitivity and specificity analysis of the lineage-related antibodies in acute leukemia immunophenotyping are coincident with St Jude immunophenotyping project. It seems only that CD117 is superior to MPO in defining AML, but the sensitivity and specificity analysis of CD22 and CD79 are similar in defining B-lineage ALL, therefore, anyone of them may be selected as your need.

[Immunophenotypes in 115 patients with acute myeloid leukemia by multi-color flow cytometry]

Immunophenotyping has become common in the diagnosis and classification of leukemia. To evaluate the immunophenotype of acute myeloid leukemia (AML), multiparameter flow cytometry and CD45/SSC gating were used to analyze the surface and cytoplasmic antigen expressions in 115 cases of AML. The results were compared with the French-American-British (FAB) Cooperative Group classification to help define the best use and role of multiparameter flow cytometry in the diagnosis and proper classification of AML. The results showed that CD38, CD38 and CD13 were the most commonly expressed antigen (94.8%, 91.3% and 89.6%, respectively). CD7 was the most commonly expressed lymphoid antigen (20.2%), followed by CD19 (16.5%) and CD2 (15%). Some immunophenotypes correlated with FAB type, including increased frequency of CD2 in M(3); lack of HLA-DR, CD34 and CD56 expression in M(3); increased frequency of CD19 in M(2), CD14 and CD56 in M(5) and lack of MPO in M(0). In conclusion, multiparameter flow cytometry is a reliable technique in the diagnosis of AML, and some immunophenotypes correlate with FAB type.

Clonal plasma cells from monoclonal gammopathy of undetermined significance, multiple myeloma and plasma cell leukemia show different expression profiles of molecules involved in the interaction with the immunological bone marrow microenvironment

The immunological bone marrow (BM) microenvironment plays a major role in controlling growth and survival of clonal plasma cells (PC); this might translate into different patterns of expression of molecules involved in immune responses on PC from different types of monoclonal gammopathies (MG). We have studied the expression of a group of nine such molecules on both BMPC and the plasma of 61 newly diagnosed MG patients (30 MG of undetermined significance (MGUS), 27 multiple myeloma (MM) and four plasma cell leukemia (PCL)) and five normal individuals. Clonal PC from all MG displayed significantly increased levels of CD56, CD86 and CD126, and decreased amounts of CD38 (P<0.001). Additionally, HLA-I and beta2-microglobulin were abnormally highly expressed in MGUS, while CD40 expression was decreased in MM and PCL (P<0.05). Interestingly, a progressive increase in the soluble levels of beta2-microglobulin was found from MGUS to MM and PCL patients (P=0.03). In contrast, all groups showed similar surface and soluble amounts of CD126, CD130 and CD95, except for increased soluble levels of CD95 observed in PCL. Overall, those phenotypic differences are consistent with increased antigen presentation and costimulatory capacities in MGUS, which progressively deteriorate in malignant MG (MM and PCL).

Differential expression of the cytokine receptors for human interleukin (IL)-12 and IL-18 on lymphocytes of both CD45RA and CD45RO phenotype from tonsils, cord and adult peripheral blood

The objective of this study was to demonstrate the variable expression of cytokine receptors on naive versus memory human CD4+ T cell subpopulations in tonsillar tissue, cord blood and adult blood. We prove that the receptors for both interleukin (IL)-12 and IL-18 are expressed exclusively on memory T cells. This observation was seen not only on the CD45RO+ memory T cells but also on a significant percentage of the CD45RA+, CD62L-, CD27- and CCR7- populations. Furthermore, CD45RA+ CD62L+, CD27+ or CCR7+ CD4+ T cells that expressed IL-12Rbeta1 and IL-18Ralpha did not express CD31, a marker for recent thymic emigrants. We reveal that cord blood lymphocytes do not express IL-12Rbeta1 whereas IL-18Ralpha expression was detected at low levels. Importantly, the IL-12Rbeta2 signalling chain, which is absent in all resting T cells, was up-regulated in both CD45RA+ and CD45RO+ T cells as a result of stimulation with anti-CD3 and anti-CD28 in vitro. This observed up-regulation was, however, restricted to 80% of the total CD4+ population. Finally, a very small proportion of the CD4+ CD45RO+ tonsillar T cells expressed the IL-12 and IL-18 receptors, thereby establishing the differential expression of these receptors between peripheral and tonsillar memory T cell subpopulations.

Antibody microarray for correlating cell phenotype with surface marker

To correlate cell surface markers with the cell phenotype, an antibody microarray prepared by covalently immobilizing antibodies onto a cellulose membrane and subsequent immunocytochemical staining were employed. The direct binding assay of a lymphoblastic leukemia cell line on the microarray showed that the immobilized antibody served to capture cells expressing the specific antigen. The density of bound cells increased linearly with an increasing content of antigen-expressing cells in suspension. The method was further applied to the analysis of surface antigens expressed on neural stem cells. A binding assay was performed with neural cells obtained from the neurosphere culture of the rat fetal striatum on a microarray spotted with eight kinds of antibodies and four different proteins, followed by immunocytochemical staining of cells bound to the microarray using antibodies to the intracellular markers of immature (nestin and vimentin) and mature (beta-tubulin III and glial fibrillary acidic protein) neural cells. As a result, the phenotype of bound cells could be correlated to surface antigen expression, which illustrated the potential of the solid-phase cytometry developed here for the identification of surface markers.

Inhibition of tumour necrosis factor-alpha by antisense targeting produces immunophenotypical and morphological changes in injury-activated microglia and macrophages

Microglia respond in a stereotypical pattern to a diverse array of pathological states. These changes are coupled to morphological and immunophenotypical alterations and the release of a variety of reactive species, trophic factors and cytokines that modify both microglia and their cellular environment. We examined whether a microglial-produced cytokine, tumour necrosis factor-alpha (TNF-alpha), was involved in the maintenance of microglial activation after spinal cord injury by selective inhibition using TNF-alpha antisense deoxyoligonucleotides (ASOs). Microglia and macrophages harvested from 3 d post-contused rat spinal cord were large and rounded (86.3 +/- 9.6%). They were GSA-IB4-positive (GSA-IB4(+)) (Griffonia simplicifolia lectin, microglia specific; 94.8 +/- 5.1%), strongly OX-42 positive (raised against a type 3 complement/integrin receptor, CD11b; 78.9 +/- 9.1%), ED-1 positive (a lysosomal marker shown to correlate well with immune cell activation; 97.2 +/- 2.6%) and IIA positive (antibody recognizes major histocompatibility complex II; 57.2 +/- 5.6%), indicative of fully activated cells, for up to 48 h after plating. These cells also secreted significant amounts of TNF-alpha (up to 436 pg/microg total protein, 16 h). Fluoroscein isothiocyanate-labelled TNF-alpha ASOs (5, 50 and 200 nm) added to the culture medium were taken up very efficiently into the cells (> 90% cells) and significantly reduced TNF-alpha production by up to 92% (26.5 pg/microg total protein, 16 h, 200 nm TNF-alpha ASOs). Furthermore, few of the treated cells at this time were round (5.4 +/- 2.7%), having become predominantly spindle shaped (74.9 +/- 6.3%) or stellate (21.4 +/- 2.7%); immunophenotypically, although all of them remained GSA-IB4 positive (91.6 +/- 6.2%), many were weakly OX-42 positive and few expressed either ED-1 (12.9 +/- 2.5%) or IIA (19.8 +/- 7.4%). Thus, the secretion of TNF-alpha early in spinal cord injury may be involved in autoactivating microglia/macrophages. However, at the peak of microglial activation after injury, the activation state of microglia/macrophages is not stable and this process may still be reversible by blocking TNF-alpha.

Immunohistochemical analysis of Hodgkin's disease in Kampala, Uganda

BACKGROUND

Histopathological examination remains crucial for diagnosis and classification of Hodgkin's disease (HD) but poses problems when characteristic features of HD are not present and hence the value of immunohistochemistry. Experience with immunohistochemistry in developing countries is limited due to cost.

OBJECTIVE

To describe the immunophenotypic and histologic types of Hodgkin's disease in Kampala, Uganda

DESIGN

A cross-sectional study.

SETTING

Makerere University Medical School, Department of Pathology.

METHODOLOGY

Two hundred formalin fixed, paraffin- embedded biopsies, which had been previously diagnosed as Hodgkin's disease in the Makerere University, Department of Pathology from 1980--2000, were re-assessed with haematoxylin and eosin. The sections were then subjected to immunohistochemistry using monoclonal antibodies: leucocyte common antigen (CD45), antibodies to Reed-Sternberg cells (CD15, CD30) and to B cells (CD20).

RESULTS

Of the 200 biopsies, 171 (71.3%) were diagnosed as Hodgkin's disease using immunohistochemistry. The mean age of the 171 cases was 26.1(SD 16.2) years; mode 20.0; median 22.5 years. The 15-24 year age group was most affected (47.2%). There were more males (65.9%) than females and most were Baganda who are the main tribe in the central region of Uganda. Mixed cellularity (35.7 %) and lymphocyte depleted (24.6 %) HD were the commonest histological types. Classic HD (CD30, CD 15, CD20, CD45) was the most commonest (77.8%) immunophenotype.

CONCLUSION

Classic Hodgkin's disease (CD30, CD 15, CD20 and CD45) is the most commonest immunophenotype in Kampala, Uganda, and mixed cellularity and Iymphocyte depleted are the main histologic subtypes.

Establishment of a microplate assay for flow cytometric assessment and it is use for the evaluation of age-related phenotypic changes in canine whole blood leukocytes

The effectiveness of flow cytometric assays for canine use is still requiring standardization. Despite several studies using purified mononuclear cells, no methodology or reference ranges are available for immunophenotyping of whole blood leukocytes (WBL). Fresh and pre-fixed WBL were used to identify cell-subsets, (Thy-1(+)/CD5(+)/CD4(+)/CD8(+)/CD21(+) and CD14(+)) and measure MHC-II, CD45RA/CD45RB expression. We described here an efficient method for fast quantification of canine-WBL, using pre-fix in a microplate assay, which allows long-term sample storage prior to phenotyping. Decreased percentage of CD5(+)-T-cells within the lymphocyte-gate and increased percentage of CD21(+)-B-cells were observed in young animals, which led to higher T/B cell ratios in middle-aged dogs. Lower numerical counts of Thy-1(+), CD4(+), CD8(+) and CD21(+) lymphocyte were observed when compared to young animals. In addition, we identified an age-related decline of MHC-II/CD45RA expression by lymphocytes. We proposed an improved method for phenotyping of canine peripheral blood mononuclear cells (PBMC) that has significant use for researchers and veterinary clinicians. The hematological changes of senescence previously identified on PBMC could be adequately reproduced on features identified by whole blood. Furthermore, this study supplies normal range references as baseline standards for clinical purposes, besides specific immunological parameters to monitor canine aging process.

Gammadelta and alphabeta T-cell acute lymphoblastic leukemia: comparison of their clinical and immunophenotypic features

Gammadelta-T-cell acute lymphoblastic leukemia (ALL) is a rare variant of ALL. The comparison of some clinical and laboratory features in children and adults with gammadelta-T-ALL or alphabeta-ALL showed that in gammadelta-T-ALL the CD45RAEth/CD45RO+ phenotype was predominant, the hemoglobin concentration was lower in children and the presence of splenomegaly and the white cell counts was higher in adults.

Flow cytometry identification and characterization of mononuclear cell subsets in the neotropical primate Saimiri sciureus (squirrel monkey)

BACKGROUND

The neotropical primate squirrel monkey is used in many areas of biomedical research including neuroendocrinology, immunology and infectious diseases. However, research has been hampered by the lack of immunological tools for this primate.

METHODS

A series of 67 commercially available monoclonal antibodies to human CD antigens or cytokines were tested on Saimiri mononuclear cells and the specificity was assessed by double staining using flow cytometry.

RESULTS

Monoclonal antibodies defining the main mononuclear cells subsets (monocytes, B, T, including CD4 and CD8 T cells) as well as activation markers have been identified. The conditions to specifically identify the various cell subsets using two color flow cytometry and establish their relative proportions have been set-up. We also have established normal values of the main circulating mononuclear cell subsets for adult Saimiri sciureus monkeys from the breeding unit of Institut Pasteur in French Guiana. The distribution between spleen, blood and lymph nodes has been compared.

CONCLUSIONS

These tools allow documenting the phenotype of most Saimiri mononuclear cell subsets and assessing their activation level. This opens new perspectives for vaccinology and immunopathology research in this experimental non-human primate host, in particular for malaria research.

Impaired Dendritic Cell Immunophenotype and Function in Heart Transplant Patients Undergoing Active Cytomegalovirus Infection

BACKGROUND

Human cytomegalovirus (HCMV) infects dendritic cells (DCs) in vitro and inhibits their maturation properties and their ability to stimulate T-cell proliferation and cytotoxicity. This study analyzed HCMV infection of DCs in vivo.

METHODS

We compared blood DCs and monocyte-derived DCs from heart-transplant patients undergoing an acute HCMV infection with DCs obtained from HCMV-negative transplant patients. Diagnosis of active HCMV infection was established by antigenemia test.

RESULTS

We detected viral RNA and antigens in defined DC subsets obtained from patients undergoing an active HCMV infection. In addition, we found an impaired immunophenotype in immature DCs from HCMV-positive subjects and a reduced ability of mature DCs from the same group of patients to stimulate allogenic T-cell proliferation.

CONCLUSIONS

The impaired immunophenotype and function detected in DCs from transplant patients undergoing an active HCMV infection may be a mechanism used by the virus to interfere with early immune functions and thereby contributing to the HCMV-induced immunosuppression in these patients.

Relative contributions of enzyme cytochemistry and flow cytometric immunophenotyping to the evaluation of acute myeloid leukemias with a monocytic component and of flow cytometric immunophenotyping to the evaluation of absolute monocytoses

We evaluated the contributions of enzyme cytochemical stains and flow cytometric immunophenotyping (FCI) data to detection of monocytic cells (MCs) in acute myelomonocytic and acute monocytic leukemias (AMMLs and AMoLs) and compared FCI findings in AMoL, chronic myelomonocytic leukemia (CMML), and normal peripheral blood (PB) and bone marrow (BM) monocytes to classify and evaluate absolute monocytoses (AMs). We reviewed 10 AMMLs and 6 AMoLs with a-naphthyl-acetate esterase (ANAE) and a-naphthyl-butyrate esterase stains and a complete FCI profile and compared FCI data for 6 AMoLs, 7 CMMLs, 2 AMs, and normal monocytes. We confirmed increased sensitivity of ANAE staining to FCI data in detecting MCs in AMML and AMoL. CD14 was insensitive for confirming MCs; other characteristic markers of MCs were absent or partially lost in AMML and AMoL. Aberrant expression of CD56 (detected in 50% of AMMLs and AMoLs), CD34, and CD117 indicated malignancy. The mature MCs of the CMMLs revealed variable FCI abnormalities (partial loss of CD13, CD14, and CD15; expression of CD56), as in the monoblasts of AMoL. These FCI abnormalities in morphologically mature MCs might indicate markers for CMML. AMs revealed FCI abnormalities, indicating clues to their correct classification as CMML.

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma With Trisomy 12 and Focal Cyclin D1 Expression: A Potential Diagnostic Pitfall

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and mantle cell lymphoma usually are distinctly different in regard to clinical presentation, morphology, immunophenotype, and molecular/genetic findings. In spite of this, select cases may show overlapping characteristics and represent a diagnostic challenge. Cyclin D1 immunohistochemical staining is usually envisioned as a definitive method for resolving this differential diagnosis, with positivity supporting a diagnosis of mantle cell lymphoma. We report a case involving a 58-year-old man with a diagnosis of CLL/SLL for several years. A lymph node excision was performed after increased adenopathy was noted in the cervical region. The excised lymph node showed typical morphologic findings of CLL/SLL, including the presence of characteristic proliferation centers. Cyclin D1 staining, using 3 different antibodies, was present in scattered prolymphocytes and paraimmunoblasts, mostly within proliferation centers. Fluorescence in situ hybridization and conventional cytogenetics demonstrated trisomy 12 and an absence of t(11;14) in lymph node tissue. Focal cyclin D1 expression by immunohistochemistry in nodal CLL/SLL is quite unusual and is discussed as a potential diagnostic pitfall.

Immunophenotyping characteristic of the major lymphocyte populations and subpopulations in patients during salmonella infection

AIM

To study the quantitative changes in the major lymphocyte populations and subpopulations in the peripheral blood of patients during salmonellosis and find correlations of these changes with disease severity and bacterial clearance.

MATERIAL AND METHODS

The study included 24 adult patients with culture-proven gastrointestinal salmonellosis. Flow-cytometry was used to identify CD19+ (B lymphocytes), CD2+ (total T lymphocytes), CD3(+)CD4+ (helper T cells), CD3(+)CD8+ (suppressor/cytotoxic T lymphocytes), CD4(+)CD29+ and CD4(+)CD45(-)RA+ (helper/ inducer subpopulation and naive Tlymphocytes) in the acute and the convalescent phases of disease. The absolute number and percentage of cells in 1 microl of peripheral blood were also determined. Immunophenotype analysis was conducted on an EPICS XL-MCL flow cytometer, Coulter, USA using monoclonal antibodies produced by the same firm.

RESULTS

T and B lymphocytes and the immunocompetent T cells were slightly decreased transiently in the acute phase of the disease. Helper T lymphocytes were slightly increased with a significant increase observed of helper/inducer cells and decrease of the naive T lymphocytes.

CONCLUSION

The increase of B lymphocytes at the height of salmonellosis bears additionally a diagnostic significance in determining the severity of the disease while the increase of the helper T lymphocytes can be a prognostic marker of early bacterial clearance.

[Immunoglobulin heavy chain gene rearrangements in the monoclonal gammopathies]

Plasma cell neoplasia occurs as a result of the expansion of an immunoglobulin-secreting B-cells clones, known as monoclonal component or M component. Malignant neoplasias include multiple myeloma and Waldenstrom macroglobulinemia, while premalignant conditions comprise monoclonal gammopathies of unknown significance (MGUS). MGUS present a monoclonal component with no signs of multiple myeloma, Waldenström macroglobulinemia, primary amyloidosis or other disorders. Pathological, radiological and clinical features are required for the diagnosis. Approximately 25% of patients with MGUS will become multiple myeloma, primary amiloidosis, macroglobulinemia, or other lymphoproliferative disease, which would be a premyelomatous condition. The objective of this study was to determine the clinical implications of immunophenotyping by flow cytometry and of the detection of clonality by molecular biology. A total of 32 patients were studied. Seven of them were diagnosed with multiple myeloma, and 25 with monoclonal gammopathy under study. These 32 patients were divided into four groups, based on their clinical data and flow cytometry outcome. In patients with non-diagnostic flow cytometry detection of immunoglobulin heavy chain gene rearrangements by PCR was performed, and monoclonality was found in 59% of the cases. The study of immunoglobulin heavy chain gene rearrangements by molecular biology allows a more sensitive detection of clonality.

IgVH mutations in blastoid mantle cell lymphoma characterize a subgroup with a tendency to more favourable clinical outcome

Mantle cell lymphoma (MCL) is associated with a very unfavourable clinical course. This is particularly true for mantle cell lymphoma of the blastoid subtype (MCL-b). In order to define prognostic factors, we analysed the impact of immunoglobulin heavy chain variable (IgV H) gene somatic hypermutations on clinical outcome in a series of 21 cases of morphologically, phenotypically, and genotypically well-characterized MCL-b. Testing and estimation were performed using log-rank statistics and displayed on Kaplan-Meier graphs. Thirteen of 21 cases of MCL-b revealed a homology rate of > or = 99% compared to IgV H germ-line sequences in the databases and were scored as non-mutated. Eight of 21 cases (38%) of MCL-b were mutated. In MCL-b the mutation frequency was usually low and the mutation pattern was only rarely antigen-selected, in contrast to a control group of 11 cases with morphologically almost identical, but phenotypically and genotypically clearly distinguishable, diffuse large B cell lymphoma, derived, most likely, from germinal centre B cells. In our series of 21 MCL-b, positive IgV H mutational status, irrespective of varying homology thresholds, had no statistically significant prognostic impact on event-free or overall survival. However, mutated MCL-b tended to present more frequently at an earlier stage and without bone marrow involvement and to show lower rates of relapse and death, resulting in a more favourable clinical outcome.