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Unsupervised immunophenotypic profiling of chronic lymphocytic leukemia.

BACKGROUND: Proteomics and functional genomics have revolutionized approaches to disease classification. Like proteomics, flow cytometry (FCM) assesses concurrent expression of many proteins, with the advantage of using intact cells that may be differentially selected during analysis. However, FCM has generally been used for incremental marker validation or construction of predictive models based on known patterns, rather than as a tool for unsupervised class discovery. We undertook a retrospective analysis of clinical FCM data to assess the feasibility of a cell-based proteomic approach to FCM by unsupervised cluster analysis. METHODS: Multicolor FCM data on peripheral blood (PB) and bone marrow (BM) lymphocytes from 140 consecutive patients with B-cell chronic lymphoproliferative disorders (LPDs), including 81 chronic lymphocytic leukemia (CLLs), were studied. Expression was normalized for CD19 totals, and recorded for 10 additional B-cell markers. Data were subjected to hierarchical cluster analysis using complete linkage by Pearson's correlation. Analysis of CLL in PB samples (n = 63) discovered three major clusters. One cluster (14 patients) was skewed toward "atypical" CLL and was characterized by high CD20, CD22, FMC7, and light chain, and low CD23. The remaining two clusters consisted almost entirely (48/49) of cases recorded as typical BCLL. The smaller "typical" BCLL cluster differed from the larger cluster by high CD38 (P = 0.001), low CD20 (P = 0.001), and low CD23 (P = 0.016). These two typical BCLL clusters showed a trend toward a difference in survival (P = 0.1090). Statistically significant cluster stability was demonstrated by expanding the dataset to include BM samples, and by using a method of random sampling with replacement. CONCLUSIONS: This study supports the concept that unsupervised immunophenotypic profiling of FCM data can yield reproducible subtypes of lymphoma/chronic leukemia. Expanded studies are warranted in the use of FCM as an unsupervised class discovery tool, akin to other proteomic methods, rather than as a validation tool.

ADP-ribosyl Cyclase 1↗

Primary diagnosis and REAL/WHO classification of non-Hodgkin's lymphoma by fine-needle aspiration: cytomorphologic and immunophenotypic approach.

The Revised European American lymphoma (REAL) and World Health Organization (WHO) classification of non-Hodgkin's lymphoma (NHL) relies on the constellation of cytologic, phenotypic, genotypic, and clinical characteristics of NHL. For the most part, the classification does not rely on architectural pattern for classification of neoplasms. This classification makes it possible to diagnose and classify lymphomas by fine-needle aspiration (FNA). In this study, we attempted to evaluate the accuracy of FNA in diagnosing and classifying NHL within the context of the REAL/WHO classifications. Cases included only those in which FNA was the primary diagnosis, followed by a surgical biopsy for confirmation. Flow cytometry (FCM) for phenotyping was carried out whenever material was available. Two groups of pathologists were identified. Group A consisted of pathologists with background training in cytopathology and/or hematopathology (three pathologists). Group B consisted of experienced surgical pathologists with no training in cytopathology and/or hematopathology (four pathologists). Seventy-four cases were included in the study. FCM phenotyping was performed in 53 cases (71%). Large cell lymphoma constituted 63% of the cases. The remaining lymphomas included Burkitt's, small lymphocytic, lymphoblastic, follicle center cell, Ki-1, mantle cell, marginal zone, and natural killer cell lymphoma. The diagnosis of lymphoma was rendered for all cases. The correct classification was seen in 63% of the cases. Classification was more accurate in immunophenotyped than in nonimmunophenotyped cases (84% vs 33%; P = 0.00004). Group A pathologists showed higher incidence of proper classification than group B (80% vs 56%; P = 0.046). The diagnosis and classification of NHL can be achieved in a large number of cases on FNA material. This accuracy can be increased if cytomorphologic criteria are established for different entities of NHL aided by FCM for phenotyping.

Biopsy, Needle↗

Quantitative analysis of integrin expression in effusions using flow cytometric immunophenotyping.

We have previously shown that flow cytometric (FCM) immunophenotyping is a useful adjunct to morphology, in the diagnosis of serous effusions. The objective of the present study was to evaluate the possible application of FCM to quantitative analysis of adhesion molecule expression in this clinical setting. Fresh frozen cells from 67 effusions underwent quantitative analysis of alphaV, alpha6, beta1, and beta3 integrin subunit expression, using FCM. Specimens were diagnosed as carcinoma (n = 48), reactive (n = 12), or malignant mesothelioma (MM; n = 7) using morphology and, in selected cases, immunocytochemistry prior to FCM analysis. Antibodies against established epithelial, lymphoid, and mesothelial cell epitopes (Ber-EP4, anti-epithelial membrane antigen; (EMA), anti-CD45, anti-CD14, and anti-CD15) completed the panel. Results (percentage of cells expressing the antigen) were analyzed for relationship with the morphologic diagnosis. Frequent expression of the alphaV, alpha6, and beta1 subunits was seen in all diagnostic groups, with significantly higher expression of the alpha6 subunit in MM (P = 0.029, Kruskal-Wallis H test). The beta3 integrin subunit was not detected in any of the specimens. Ber-EP4 and CD15 expression was significantly higher in carcinomas compared with reactive effusions and MM (P < 0.001 and P = 0.001, Kruskal-Wallis H test), and EMA expression was higher in carcinomas and MM, compared with reactive specimens (P < 0.001, Kruskal-Wallis H test). In conclusion, FCM is an efficient tool for quantitative analysis of adhesion molecules in effusions. The high alpha6 integrin subunit expression in MM suggests involvement of this receptor in tumor attachment to laminin. The frequent expression of the alphaV and beta1 subunits support attachment to fibronectin and vitronectin as the major ECM ligands in body cavities.

Ascitic Fluid↗

Detection of monocyte/macrophage cell populations in effusions: a comparative study using flow cytometric immunophenotyping and immunocytochemistry.

The objective of the present study was to compare the efficiency of immunophenotyping using flow cytometry (FCM) and immunocytochemistry (ICC) in the detection of macrophages in serous effusions. Cytoblock sections from 90 effusions were stained for the monocyte/macrophage marker CD14, using ICC. Fresh-frozen samples of all cases were analyzed for CD14 expression, using FCM. Epithelial, lymphoid, and mesothelial cell populations were identified using antibodies against Ber-EP4, CD45, and N-cadherin, respectively. Results were compared with clinical parameters and morphological diagnosis. Thirty-nine specimens were cytologically diagnosed as malignant, containing tumor cells of nonhematologic origin, whereas 46 were interpreted as benign. Two additional specimens were diagnosed as indeterminate or suspicious for malignancy, and 3 specimens contained lymphoma cells. CD14-positive cells were detected in 85/90 (94%) of effusions using FCM, and in all 90 specimens using ICC. The percentage of CD14-positive cells was highly variable, but in some specimens was as high as 76% using FCM and 85% using ICC. A good association was observed between the two methods in the detection of CD14-positive cells (P < 0.001). The presence of macrophages in effusions showed an association with female gender, using both FCM (P = 0.002) and ICC (P = 0.011), but none with effusion site, patient age, clinical and cytological diagnosis, or presence of Ber-EP4-positive cells (P > 0.05). The presence of Ber-EP4-positive cells showed a strong association with the cytological diagnosis of malignancy (P < 0.001). In conclusion, macrophages are a significant cell population in effusions, of both benign and malignant etiology, due to both their size and their possible confusion with cancer cells. Both FCM and ICC aid in the recognition of these cells, and thus provide an effective tool for the identification of different cell populations in effusions.

Adult↗

Fine-needle aspiration cytology combined with flow cytometry immunophenotyping is a rapid and accurate approach for the evaluation of suspicious superficial lymphoid lesions.

The authors report a prospective study on 88 samples of superficial lesions (lymph nodes, skin nodules, and breast tumors), performed by fine-needle aspiration cytology (FNAC) in 74 patients, allowing (i) morphologic analysis combined with immunophenotyping by flow cytometry (FCM) and (ii) a cytogenetic study in 33 cases. Thirty-nine FNAC (44.3%) were performed at the time of diagnosis. The cytology results were correlated with histopathologic examination in 32 cases. Forty-nine FNAC (55.7%) were performed in the context of follow-up of a lymphoma and the results were correlated with those of histopathologic examination in 14 cases. In this study, the concordance between FNAC plus FCM and histopathologic examination was 90% for low-grade non-Hodgkin's malignant lymphomas (NHLs) and 83% for high-grade NHL. The limits of this morphologic and phenotypic approach are (i) partial tumor infiltrations, (ii) Hodgkin lymphoma, and (iii) T-cell NHL. In conclusion, it may be said that this combined approach is very useful for diagnosis and follow-up of patients but requires teams experienced in the sampling technique and the morphologic diagnosis of the various types of low-grade NHL in which supplementary ancillary studies may be performed when morphology and flow cytometry immunophenoyping are not conclusive.

Adolescent↗

Comparison of two techniques (flow cytometry and alkaline immunophosphatase) in the evaluation of alveolar macrophage immunophenotype.

The alveolar macrophage (AM) plays an essential role in the pathogenesis of interstitial lung diseases. The expression of specific membrane antigens is related to the functional or madurative status of the cells of mononuclear phagocyte system. The aim of this study was to analyze the expression of several markers (HLA-DR, CD11b, CD16, CD14) in AM obtained by bronchoalveolar lavage from control patients (n = 6), patients with sarcoidosis (n = 6), diffuse neoplastic infiltration of the lung (n = 7), pulmonary fibrosis (n = 4), and hypersensitivity pneumonitis (n = 3) by two evaluation techniques (flow cytometry and alkaline immunophosphatase). In the light of the results we can conclude that in the immunophenotypical study of the alveolar macrophage, flow cytometry (with semiquantitative evaluation to avoid the problem of autofluorescence) is a useful tool in the evaluation of those antigens that are only weakly or moderately expressed on AM (CD11b or CD14), whereas the alkaline immunophosphatase technique is of great interest in the evaluation of those that are strongly expressed (i.e., HLA DR). Additionally, the variable expression of the different antigens in the different alveolar-interstitial pathological states is patent in some diseases.

Alkaline Phosphatase↗

Immunophenotyping of lymphocytes in liver tissue of patients with chronic liver diseases by flow cytometry.

Immunological factors are important in the pathogenesis of a spectrum of hepatobiliary diseases. To characterize the nature of specific immunological responses in liver disease, we determined lymphocyte changes in liver tissue and in blood using flow cytometry. A total of 113 liver biopsy specimens was collected from patients with the following diseases: 19 chronic hepatitis B; 39 chronic non-A, non-B hepatitis; 27 alcoholic liver disease; 10 hepatic malignancy; 8 autoimmune hepatitis; 6 fatty liver and 4 primary biliary cirrhosis. The lymphocytes were isolated from the liver biopsy specimens by mechanical and enzymatic methods. The lymphocyte yield was 7,901 +/- 575 cells/mg of liver tissue. The viability of lymphocytes was 97.7% +/- 0.3%. Lymphocytes were stained with four pairs of two-color mixed fluorescein-conjugated monoclonal antibodies, including T4-T8 (CD4/CD8), T11-B1 (CD2-CD20), NKH1-T8 (CD56-CD8), IL-2R1-T11 (CD25-CD2), and the ratios were determined by an Epics Profile flow cytometer. Immunophenotyping of lymphocytes in whole blood samples was simultaneously analyzed. Variability in lymphocyte yield and different patterns of lymphocyte subsets were found in the liver biopsy specimens. The yields of lymphocytes from patients with chronic non-A, non-B and autoimmune hepatitis were highest, and the lowest yield was from patients with fatty liver. Patients with primary biliary cirrhosis, fatty liver and hepatic malignancy had relatively high ratios of CD4/CD8, CD56/CD8 and CD25/CD2; whereas patients with chronic hepatitis B, autoimmune hepatitis and non-A, non-B hepatitis had lower ratios of CD4/CD8, CD56/CD8 and CD25/CD2. No difference in lymphocyte ratios between the patients with cirrhotic and noncirrhotic alcoholic liver disease was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Separation↗

Modulation of the immunophenotype of ovarian cancer cells by N,N-dimethylformamide and transforming growth factor-beta 1.

Exposure of HOC-7 ovarian adenocarcinoma cells to regulators of cell differentiation caused inducer-dependent alterations of the antigenic pattern of the cells. Immunocytochemistry revealed that N,N-dimethylformamide (DMF) elevated the membrane staining for epidermal growth factor (EGF)-receptor and for desmoplakins I and II. DMF also stimulated cytoplasmic and surface labeling for CA 125 and the deposition of fibronectin into the extracellular matrix. Stimulation of fibronectin was also seen after addition of transforming growth factor (TGF)-beta 1. These responses were quantified using a fixed-cell, enzyme-linked immunosorbent assay (ELISA) and revealed that DMF dose-dependently induced expression of EGF-receptor, CA 125, fibronectin, and desmoplakins I and II. TGF-beta 1 stimulated fibronectin and desmoplakins I and II only. Production of EGF and TGF-alpha was not affected by these inducers. Immunocytochemistry, ELISA and Western blotting showed that both inducers caused down-regulation of myc oncoproteins. DMF was more effective in changing the immunophenotype of HOC-7 cells than TGF-beta 1. Desmoplakins I and II demonstrated elevated epithelial differentiation, whereas fibronectin indicated stimulation of extracellular matrix formation. Elevated EGF-receptor could not compensate for the growth inhibition induced by DMF. The expression of myc oncoproteins was inversely related to cell proliferation. CA 125, however, seems to be unrelated to cell growth.

Blotting, Western↗

Immunophenotypic and ultrastructural heterogeneity of macrophage differentiation in bone marrow and fetal hematopoiesis of mouse in vitro and in vivo.

The present in vitro study revealed marked differences in immunophenotypic expression and ultrastructure among macrophage colony-stimulating factor (M-CSF)-derived, granulocyte-macrophage colony-stimulating factor (GM-CSF)-derived, and multi-CSF-derived macrophages. M-CSF-derived macrophages were larger and had more markedly differentiated intracellular organelles and more cytoplasmic projections than GM-CSF-or multi-CSF-derived macrophages. By the combined method of ultrastructural peroxidase cytochemistry and immunoelectron microscopy, ER-MP12 was demonstrated mainly on blastic cells; ER-MP20 on promonocytes, monocytes, and immature macrophages; and F4/80 or BM8 on immature and mature macrophages and monocytes. Macrophage heterogeneity was demonstrated to occur at the stage of macrophage precursor cells, and macrophage differentiation was different between bone marrow hematopoiesis and early fetal hematopoiesis. In vivo, F4/80- or BM8-positive (+) macrophages and ER-MP12 (+) cells developed in the yolk sac prior to the appearance of ER-MP20 (+) monocytic cell series. These results imply that CSFs are important factors for the generation of phenotypic heterogeneity of macrophage populations not only in bone marrow but also in fetal hematopoiesis, suggesting that there are different pathways of macrophage differentiation.

Animals↗

High-Dimensional Immunophenotyping of Post-COVID-19 and Post-Influenza Patients Reveals Persistent and Specific Immune Signatures After Acute Respiratory Infection.

Long-term consequences of SARS-CoV-2 infection are unknown since recovered individuals can experience symptoms and latent viral reactivation for months. Indeed, acute post-infection sequelae have also been observed in other respiratory viral infections, including influenza. To characterize post-COVID-19 and post-influenza induced alterations to the cellular immunome, peripheral blood mononuclear cells (PBMCs) were obtained from patients 3 months after recovery from COVID-19 (n&#x2009;=&#x2009;93) or influenza (n&#x2009;=&#x2009;25), and from pre-pandemic healthy controls (n&#x2009;=&#x2009;25). PBMCs were characterized using a 40-plex mass cytometry panel. Principal component analysis (PCA), classification models, and K-means clustering were subsequently applied. PCA identified distinct immune profiles between cohorts, with both post-COVID and post-flu patients displaying an altered chemokine receptor expression compared to pre-pandemic healthy controls. These alterations were more prominent in post-COVID patients since they exhibited highly increased expression of chemokine receptors CXCR3 and CCR6 by various lymphoid populations, while post-influenza patients mainly showed a decrease in CCR4 expression by na&#xef;ve T cells, monocytes, and conventional dendritic cells. Classification models using immunophenotyping data confirm the three groups, while K-means clustering revealed two subgroups among post-COVID patients, with younger patients showing more pronounced immune alterations in the chemokine receptor profile, independently of long COVID symptoms. In conclusion, post-COVID and post-influenza patients exhibit distinct and unique persistent immune alterations. Understanding these altered immune profiles can guide targeted therapies for post-COVID syndrome and highlight differences in immune recovery from various respiratory infections.

Humans↗

Germinal centre-like versus undifferentiated stromal immunophenotypes in follicular lymphoma.

Follicular dendritic cells (FDCs) in reactive germinal centres (GCs) show modulated expression of antigens indicative of step-wise maturation from more undifferentiated stroma. The present study compared the expression of FDC markers CD21, CD23, CD35, and chemokine CXCL13 and the stromal markers low-affinity nerve growth factor receptor (LNGFR) and CNA.42 in 35 follicular lymphoma (FL) cases with reactive lymphoic tissue. CXCL13 was expressed by follicular stroma in all FLs but most cases showed either partial (11/35 cases, 31%) or complete (10/35 cases, 29%) absence of other FDC antigens, most commonly CD23, followed by CD21 and CD35, with variable patterns of LNGFR and CNA.42 immunostaining. Only a minority of FL cases (14/35, 40%) showed stroma that resembled mature FDCs (CD23+, CD21+, CD35+) and these tumours were always associated with numerous intrafollicular T-cells, similar to reactive GCs. In the 25 FL cases that had identifiable extrafollicular tumour cells, the immunophenotype of follicular stroma showed the same variability but the extrafollicular stroma showed an absence of FDC markers, with the exception of frequent strong LNGFR staining. Stromal phenotypic changes in FL were not correlated with mean follicle size, percentage of diffuse growth, tumour mitotic rate or the proliferation index as determined by PCNA immunostaining. Serial biopsy specimens analysed in a subset of 15 patients showed either a stable stromal phenotype (seven cases, 47%) or loss of FDC antigens in tumour-associated stroma over time (seven cases, 47%). The GC-like subset of FLs, having both abundant intrafollicular T-cells and fully differentiated CD23+ FDCs, comprises a minority of FL cases that likely have different growth requirements from FLs that lack these features. The pattern of FDC antigen loss in stroma of FL is a readily assessable biological feature that appears independent of architectural growth pattern and may serve as a useful surrogate marker of tumour progression.

Biomarkers, Tumor↗

c-Kit immunophenotyping and metalloproteinase expression profiles of mast cells in interstitial lung diseases.

Diverse interstitial lung diseases (ILD) demonstrate mesenchymal infiltration by an abundance of activated mast cells whose role in parenchymal fibrogenesis remains unclear. Since mast cells differentiate in a dynamic, tissue-specific manner via signals transduced by c-Kit receptor, we examined the effect of ILD microenvironments on c-Kit expression and metalloproteinase phenotypes of mesenchymal mast cell populations. Immunohistochemical and flow cytometric analyses characterized surface expression of c-Kit on mast cells in tissues obtained from patients with idiopathic pulmonary fibrosis, systemic sclerosis, sarcoidosis, and lymphangioleiomyomatosis, thus identifying a unique immunophenotype not shared by normal lung mast cells. Isolation of c-Kit+/FcepsilonRI+/CD34- mast cells via immunocytometric sorting of heterogeneous cell populations from mechanically disaggregated lung tissues permitted analysis of gene expression patterns by two-step real-time polymerase chain reaction. Transcriptional profiling identified expression of c-Kit and the neutral serine proteases, tryptase and chymase, establishing the identity of sorted populations as mature mast cells. Mast cells harvested from ILD tissues demonstrated characteristic metalloproteinase phenotypes which included expression of matrix metalloproteinase (MMP)-1 and a disintegrin and metalloproteinase (ADAM)-9, -10, and -17. Immunohistochemical co-localization guided by gene profiling data confirmed expression of chymase, MMP-1, and ADAM-17 protein in subpopulations of mast cells in remodelling interstitium. Gene profiling of harvested mast cells also showed increased transcript copy numbers for TNFalpha and CC chemokine receptor 2, which play critical roles in lung injury. We conclude that ILD microenvironments induce unique c-Kit receptor and metalloproteinase mast cell phenotypes.

Cell Differentiation↗

IRTA1+ monocytoid B cells in reactive lymphadenitis show a unique topographic distribution and immunophenotype and a peculiar usage and mutational pattern of IgVH genes.

The origin and function of monocytoid B cells (MBCs) are poorly understood. Taking advantage of their strong expression of IRTA1 (a receptor that is also associated with MALT marginal zone B cells), we have comprehensively analysed MBCs in 25 cases of lymphadenitis of different aetiologies, shedding new light on the topographical distribution, immunophenotype and IgV(H) gene usage and mutational profile of this B cell subset. IRTA1(+) MBCs, although predominantly located in the subcapsular and intermediary sinuses, were also observed scattered within germinal centres (GCs) in all lymphadenitis cases examined. The molecular characterization of IgV(H) genes revealed that IRTA1(+) MBCs residing in different areas of the lymph node (subcapsular sinus, intermediary sinuses and GCs) can be clonally related (with intraclonal variation), and that those located in GCs are consistently more mutated and selected for expression of a functional antigen receptor than those located in the sinuses. Moreover, by contrast, IRTA1(+) MBCs in GCs express the memory B cell marker CD27. Finally, in toxoplasmic lymphadenitis, the IRTA1(+) MBC population shows a highly preferential usage of the V(H) genes 3-7 and 3-30 (without any obvious peculiarity in their CDR3s), possibly suggesting that a superantigen expressed by Toxoplasma gondii may be involved in the early activation of this B cell subset.

B-Lymphocyte Subsets↗

Comparison of the immunophenotypes of signet-ring cell carcinoma, solid adenocarcinoma with mucin production, and mucinous bronchioloalveolar carcinoma of the lung characterized by the presence of cytoplasmic mucin.

The latest World Health Organization (WHO) classification divides adenocarcinoma mainly into adenocarcinoma mixed subtypes, acinar adenocarcinoma, papillary adenocarcinoma, bronchioloalveolar carcinoma, and solid adenocarcinoma with mucin production, and it mentions several variants, including fetal adenocarcinoma, mucinous ("colloid") adenocarcinoma, mucinous cystadenocarcinoma, signet-ring adenocarcinoma, and clear cell adenocarcinoma. In general, the mucin-producing adenocarcinoma of the lung comprises signet-ring cell carcinoma (SRCC), solid adenocarcinoma with mucin production (SA), and mucinous bronchioloalveolar carcinoma (m-BAC), mucinous ("colloid") adenocarcinomas and/or mucinous cystadenocarcinoma, and mucoepidermoid carcinoma. As SRCC, SA, and m-BAC exhibit distinct clinical features, it is important to identify differences in their immunohistochemical characteristics to better understand their histogenesis. In this study we analysed SRCC, SA, m-BAC, normal lung, and foregut-related secretory tissue for immunohistochemical differences using tissue microarrays. SRCC and SA showed high expression of MUC1 (97.4% and 100%, respectively), cytokeratin (CK) 7 (both 100%), and thyroid transcription factor-1 (TTF-1) (81.1% and 100%, respectively). They also showed low expression of MUC5AC (25.5% and 21.1%, respectively) and MUC6 (18.3% and 10.5%, respectively), whereas m-BAC showed high expression of MUC5AC (97.5%), MUC6 (75.0%), and CK7 (94.7%), but low expression of MUC1 (57.5%), and TTF-1 (27.5%). Hierarchical clustering showed that the immunophenotypes of SRCC and SA belong to the same category as alveolar lining cells, whereas m-BAC clustered onto another branch with gastric foveolar cells and bronchial goblet cells. These immunohistochemical findings support the results of our previous clinicopathological analysis of SRCC of the lung showing that SRCC occurs anatomically in the peripheral portion of the lung rather than in the bronchial gland-bearing portion.

Adenocarcinoma↗

Immunophenotypic aberrations, DNA content, and cell cycle analysis of plasma cells in patients with myeloma and monoclonal gammopathies.

We describe the immunophenotypic and gross DNA defects in 55 patients with myeloma and 50 patients with monoclonal gammopathy and review the literature on this subject (MedLine, 1994-2000). Our data confirmed previous reports indicating that in myeloma nearly all marrow plasma cells are abnormal (98.7 +/- 8.1%). In monoclonal gammopathy the fraction of abnormal plasma cells was 35.0 +/- 32.8%. In both myeloma and monoclonal gammopathy, the most frequent aberrant phenotypic features consisted of absence of expression of CD19, strong expression of CD56, and decreased intensity of expression of CD38; aberrant expression of CD10, CD20, CD22, or CD28 was observed in less than one-third of myeloma cases. The vast majority of cases had two or more phenotypic aberrations. In the DNA studies, 7% of myeloma cases were biclonal and 93% of cases were monoclonal. In those studies with only one plasma cell mitotic cycle, 37% had normal DNA content and 63% were aneuploid (hyperploid, 61%; hypoploid, 2%). The mean percentages of plasma cells in S- and G2M phases were 4.9 +/- 8.5 and 4.4 +/- 6.9%, respectively. Thirty-eight percent of cases had more than 3% of plasma cells in S phase. In monoclonal gammopathy, the DNA index of abnormal plasma cells ranged from 0.89 to 1.30 and the percentage of diploid (31%) and aneuploid (69%) cases was not different from the results found in myeloma. The differences in percentage of abnormal plasma cells in S- (7.4 +/- 8.6%) and G2M-phases (2.4 +/- 1.7%) in patients with monoclonal gammopathy were not statistically significant.

Adult↗

Immunophenotypic characterization of normal blood CD56+lo versus CD56+hi NK-cell subsets and its impact on the understanding of their tissue distribution and functional properties.

In the present study we have compared the immunophenotypic characteristics of the CD56+lo and CD56+hi NK-cell subsets in a group of normal healthy adults. Our results show that CD56+hi NK-cells display greater light-scatter properties than CD56+lo NK-cells at the same time they have higher levels of CD25 and CD122 IL-2 chains, together with a higher reactivity for HLA-DR and CD45RO and lower levels of CD45RA, supporting that, as opposed to the majority of the CD56+lo population, CD56+hi NK-cells might correspond to a subset of activated circulating NK-lymphocytes. Higher expression of the CD2 and CD7 costimulatory molecules found for the CD56+hi NK-cells would support their greater ability to respond to various stimuli. In addition, CD56+hi NK-cells expressed higher levels of several adhesion molecules such as CD2, CD11c, CD44, CD56, and CD62L compared to CD56+lo NK-cells, supporting a particular ability of these cells to migrate from blood to tissues and/or a potential advantage to form conjugates with target cells. Interestingly, CD56+lo and CD56+hi NK-cells showed a different pattern of expression of killer receptors that might determine different activation requirements for each of these NK-cell subsets. For instance, absence or low levels of CD16 expression might explain the lower antibody-dependent cytotoxicity activity of CD56+hi NK-cells. On the other hand, the virtual absence of expression of the CD158a and NKB1 immunoglobulin-like and the greater reactivity for the CD94 lectin-like killer receptors on CD56+hi in comparison to CD56+lo NK-cells might determine different MHC-class I specificities for both NK-cell subsets, a possibility that deserves further studies to be confirmed.

Adult↗

Comparative analysis of the morphological, cytochemical, immunophenotypical, and functional characteristics of normal human peripheral blood lineage(-)/CD16(+)/HLA-DR(+)/CD14(-/lo) cells, CD14(+) monocytes, and CD16(-) dendritic cells.

Human peripheral blood (PB) CD14(lo)/HLA-DR(+) cells were initially described as a subset of mature monocytes. Recently, it has been suggested that these represent a part of a new subset of dendritic cells (DC), characterized by the coexpression of MDC-8/HLA-DR/CD16. The aim of the present paper was to analyze the morphological, cytochemical, phenotypical, and functional characteristics of PB CD16(+)/HLA-DR(+) cells compared to both PB CD14(+) monocytes and CD16(-) DC. In contrast to CD14(+) monocytes, purified CD16(+)/HLA-DR(+) cells displayed cytoplasmic veils and lacked cytoplasmic myeloperoxidase and alpha-naphthyl acetate esterase. Normal human PB CD16(+)/HLA-DR(+) cells also displayed phenotypic characteristics different from those of CD14(+) monocytes: they lacked the CD64 Fcgamma receptor, showed lower levels of CD32, and expressed higher amounts of CD16 compared to CD14(+) monocytes. They also displayed a different pattern of expression of other antigens, including CD14, HLA-DR, CD45RA, CD45RO, complement receptors and complement regulatory surface proteins, adhesion and costimulatory molecules, and cytokine receptors, among others. When compared to CD16(-) DC, CD16(+)/HLA-DR(+) cells showed reactivity for CD16, dim positivity for CD14, higher expression of both Ig- and complement-receptors and lower reactivity for HLA-DR, adhesion, and costimulatory molecules (with the exception of CD86). The CD16(+)/HLA-DR(+) cell subset displayed a higher Ig/complement-mediated phagocytic/oxidative activity than CD16(-) DC, although this activity was significantly lower than that of mature monocytes. Regarding cytokine production at the single cell level, LPS plus IFN-gamma-stimulated PB CD16(+)/HLA-DR(+) cells produced significant amounts of IL1beta, IL6, IL12, TNFalpha, and IL8; however, the percentage of cytokine-producing cells and the amount of cytokine/cell were lower in CD16(+)/HLA-DR(+) cells than in CD14(+) monocytes. In addition, upon comparing CD16(+)/HLA-DR(+) cells with CD33(+++)/CD16(-) DC, we found that the percentage of cytokine-producing cells and the amount of cytokine/cell were significantly different in both cell subsets. In summary, our results show that CD16(+)/HLA-DR(+) cells clearly display different morphologic, cytochemical, immunophenotypical, and functional characteristics compared to both mature monocytes and CD16(-) DC. Interestingly, these cells are more frequent than other DC in normal human adult PB and cord blood samples, while they are less represented in normal bone marrow.

Adult↗

T cell activation in pediatric AIDS pathogenesis: three-color immunophenotyping.

Immune activation is an important component of HIV disease in adults that may reflect a protective host response and/or be a component of immunopathogenesis. The goals of this study were to gain understanding of T cell activation in pediatric HIV disease, to assess the usefulness of T cell activation markers as surrogates for disease progression and/or early identification of infection in infants at risk, and to determine any advantages of three- compared to two-color flow cytometric immunophenotyping for the above assessments. We examined the expression of cell-surface activation antigens on the CD4 and CD8 T cells of 26 HIV-infected and 40 HIV-seronegative age-matched control children. Compared with controls, HIV-infected children showed a slight but not significant decrease in the proportion of CD4 cells that coexpressed CD45RA and L-selectin (mean of 83 vs 75% for < 2 years of age, 76 vs 62% for 2-3 years, 64 vs 56% for > or = 4 years). CD4 cells coexpressing CD38 and HLA-DR were significantly increased in HIV+ children (mean of 2 vs 6% for < 2 years of age, 3 vs 11% for 2-3 years, 2 vs 8% for > or = 4 years). There was a striking and significant increase in the proportion of CD8 cells coexpressing CD38 and HLA-DR (mean of 5 vs. 25% for < 2 years, 10 vs 41% for 2-3 years, 6 vs 31% for > or = 4 years); this double positive population of CD8 cells included cells that were approximately 1 log brighter for the expression of CD38 than for that of CD38 single-positive cells. There was a significant reduction in CD45RA+ CD8 cells (means of 92 vs 71% for < 2 years of age, 88 vs 50% for 2-3 years, 80 vs 57% for > or = 4 years) and an increase in CD57+ CD8 cells (mean of 4 vs 8% for < 2 years of age, 8 vs 22% for 2-3 years, 19 vs 31% for > or = 4 years) in HIV+ children. The inclusion of CD3 as an anchor marker for CD8 cell subsets to limit the analysis to CD3+ CD8 cells did not substantially alter the data nor enhance the differences between infected and control children compared with the analysis of all CD8 cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired Immunodeficiency Syndrome↗