CTLA-4 (=CD152), a T cell activation antigen, has been known to be homologous to CD28 in its molecular and genomic structure. Both of these two molecules are sharing their counterreceptors, B7 (CDSO) and B7-2 (CD86) and are known to play a crucial role in T cell activation. In previous our study it was reported that there are 2 forms of CTLA-4 antigen in activated human T cells, 30 kD membrane-bound form and 34 kD cytosolic-sequestered form and the former was less than 5 % of total of this antigen induced. Aims of this study are to confirm previous finding by using flow cytometry and to characterize the cytoplasmic form of human CTLA-4 by using ultrafiltration and immunoprecipitation techniques. In PHA stimulated peripheral blood lymphocyte surface expression of CTLA-4 was less than 2.1% of any of CD4+, CD8+ and CD56+ subsets. And the 34 kD form of CTLA-4 was detected in CDS+ subset only. This discrepancy confirms that 34 kD antigen is the cytoplasmic form of human CTLA-4. In ultrafiltration and subsequent Western blot analysis study this 34 kD antigen was detected in >100 kD fraction only. And in non-reducing condition this antigen formed high molecular weght complex (MW > 350 kD). In immunoprecipitation study using anti-peptide A antibody it was found that this high molecular weight complex consists of the 34 kD cytoplasmic form of CTLA-4 and previously unknown 54 kD antigen and 46 kD antigen at 1:1:8-10 ratio. And none of these 3 molecules were identified in membrane fraction of activated human T cell. The result of this study implies that CTLA-4 molecule induced upon T cell activation mainly sequestered in cytoplasrn and another signal is necessary to target this antigen on the activated T cell surface.
Antigens, CD27 ; Blotting, Western ; CTLA-4 Antigen ; Cytoplasm* ; Flow Cytometry ; Humans* ; Immunoprecipitation ; Lymphocytes ; Membranes ; Molecular Weight ; T-Lymphocytes ; Ultrafiltration

Primary Sjogren's syndrome (pSS) is a chronic autoimmune disease with welldocumented association of lymphoid malignancies during the progress of the disease. Although several types of malignancy and pseudomalignancy have been reported in pSS, low-grade non-Hodgkin's lymphomas are the most frequently observed. Reactive plasmacytosis mimicking myeloma is a very rare condition in association with pSS. We describe a 72-yr-old woman with pSS who presented with hypergammaglobulinemia, and extensive bone marrow and lymph node plasmacytosis, which mimicked multiple myeloma. In this patient, there was an abnormal differentiation of memory B cells to plasma cells in the peripheral blood suggesting underlying pathogenetic mechanism for this condition.
Aged ; Antigens, CD19/analysis ; Antigens, CD27/analysis ; Bone Marrow Examination ; Diagnosis, Differential ; Female ; Fluorescent Antibody Technique/methods ; Humans ; Multiple Myeloma/*pathology ; Plasma Cells/chemistry/*pathology ; Sjogren's Syndrome/*pathology

PURPOSE: To distinguish lupus flare-up from infection in systemic lupus erythematosus (SLE), we analyze the expression of circulating CD27(high) plasma cells in SLE patients with and without infection, in comparison to non-SLE patients with infection. MATERIALS AND METHODS: The percentage of circulating CD27(high) plasma cells was measured by flow cytometry in the following four groups: 36 SLE patients without infection, 23 SLE patients with infection, eight non-SLE patients with infection, and 26 healthy controls. RESULTS: The frequency of CD27(high) plasma cells had a correlation with the SLE disease activity index (SLEDAI) (r = 0.866, p < 0.05), level of anti-dsDNA (r = 0.886, p < 0.05), C3 (r = - 0.392, p < 0.05), and C4 (r = - 0.337, p < 0.05) in SLE patients without infection, but there was no correlation with disease activity in SLE patients with infection. Among three groups in particular-SLE without infection, SLE with infection, and non-SLE with infection-the percentages of CD27(high) plasma cells were elevated. The percentage of CD27(high) plasma cells was higher in SLE patients with infection, when compared to SLE patients without infection. CONCLUSION: The percentage of CD27(high) plasma cells is a biomarker for disease activity of SLE without infection, under correlation with SLEDAI, anti-dsDNA, and C3 and C4 level. However, when the SLE patients have an infection, the percentage of CD27(high) plasma cells is not an adequate biomarker for the survey of disease activity. The percentage of CD27(high) plasma cells may serve as a potential parameter to distinguish a lupus flare-up from infection.
Adult ; Antigens, CD27/*biosynthesis ; Bacterial Infections/complications ; Biological Markers/metabolism ; Case-Control Studies ; Female ; Flow Cytometry/methods ; Humans ; Lupus Erythematosus, Systemic/*blood/immunology ; Male ; Plasma Cells/cytology/*immunology ; Virus Diseases/complications

Multiparametric flow cytometry (MFC) allows discrimination between normal and neoplastic plasma cells (NeoPCs) within the bone marrow plasma cell (BMPC) compartment. This study sought to characterize immunophenotypes and quantitate the proportion of NeoPCs in BMPCs to diagnose plasma cell myeoma (PCM) and evaluate the prognostic impact of this method. We analyzed the MFC data of the bone marrow aspirates of 76 patients with PCM and 33 patients with reactive plasmacytosis. MFC analysis was performed using three combinations: CD38/CD138/-/CD45; CD56/CD20/CD138/CD19; and CD27/CD28/CD138/CD117. The plasma cells of patients with reactive plasmacytosis demonstrated normal immunophenotypic patterns. Aberrant marker expression was observed in NeoPCs, with negative CD19 expression observed in 100% of cases, CD56+ in 73.7%, CD117+ in 15.2%, CD27- in 10.5%, CD20+ in 9.2%, and CD28+ in 1.3%. In PCM patients, more than 20% of NeoPCs/BMPCs were significantly associated with factors suggestive of poor clinical outcomes. Patients who were CD27- or CD56+/CD27-, demonstrated shorter overall survival than patients of other CD56/CD27 combinations. Our results support the clinical value of immunophenotyping and quantifying NeoPCs in PCM patients. This strategy could help to reveal poor prognostic categories and delineate surrogate markers for risk stratification in PCM patients.
Adult ; Aged ; Aged, 80 and over ; Antigens, CD27/metabolism ; Antigens, CD56/metabolism ; Asian Continental Ancestry Group ; Bone Marrow Cells/*cytology/metabolism ; Female ; Flow Cytometry ; Humans ; *Immunophenotyping ; Kaplan-Meier Estimate ; Male ; Middle Aged ; Multiple Myeloma/metabolism/mortality/*pathology ; Neoplasm Staging ; Neoplastic Stem Cells/*cytology/metabolism ; Prognosis ; Republic of Korea ; Risk Factors