To investigate the differential expression of various types of leukocyte common antigen (LCA) isoforms during development, we analyzed human fetal lymphoid organs, including the thymus, liver, spleen, and bone marrow from 14 weeks to 29 weeks of gestational age by immunohistochemical and flow cytometric methods. In fetal thymus, over 90% of thymocytes throughout the entire fetal life expressed CD45RO and CD45RB, while CD45RA was expressed only in less than 5% of thymocytes. This expression pattern of LCA isoforms was established by a gestational age of 14 weeks or earlier, and persisted throughout the fetal period. The tissue distribution was different from each isoform; CD45RO-positive thymocytes were found in both the cortex and medulla at the 14th week with low intensity, but was localized in the cortex with increasing fetal age. CD45RB-positive thymocytes distributed mainly in the medulla from early gestational age. Among extrathymic lymphoid organs, a small portion of lymphoid cells expressing leukocyte common antigens appeared first in the liver at 10-12 weeks of gestational age and was followed by a small number in the spleen and bone marrow by 13-15 weeks. All lymphoid cells in these extrathymic lymphoid organs at this stage were CD19+ B cells. The number of these CD19+ cells increased abruptly during the early period of mid-gestational age. The pattern of tissue distribution of each LCA isoform in the fetal liver and spleen correlated well with the patterns of quantitative analysis by flow cytometry. In summary we found that different LCA isoforms expressed in cell-type-specific pattern and showed different tissue distribution during the period of fetal development, and that LCA was the earliest antigen expressed by lymphocytes in the thymus and extrathymic lymphoid organs in our series.
Antigens, CD45/*analysis ; Bone Marrow/immunology ; Female ; Fetus/*immunology ; Flow Cytometry ; Human ; Immunoenzyme Techniques ; Liver/immunology ; Lymphoid Tissue/*immunology ; Pregnancy ; Spleen/immunology

Natural killer (NK) cell neoplasms are a group of rare but highly malignant tumors. We report here one case of NK cell leukemia. A 54-yr-old woman presented with a 2-month history of progressive left neck mass. Based on the positive result of tissue PCR for Mycobacterium tuberculosis, she was at first diagnosed with tuberculous lymphadenopathy. After two weeks, she developed generalized lymphadenopathy, hepatosplenomegaly, fever and anemia. Subsequent evaluation was performed including bone marrow aspiration and biopsy. Peripheral blood smear showed leukoerythroblastic features with 31% blasts. Bone marrow was packed with agranular blastoid cells, which were periodic acid-Schiff (PAS) positive and myeloperoxidase (MPO) negative. Immunophenotyping showed that these cells were positive for CD45 and HLA-DR, whereas negative for CD3, CD5, CD7, CD10, CD13, CD14, CD19, CD20, CD22, CD33, CD34, and CD61. Because of the absence of the markers of T-cell, B-cell, and myeloid lineage-specific antigens, we added CD16/56 for the immunophenotyping and the blasts were positive (94%). The tumor cells of biopsied lymph node were only positive for CD56, consistent with NK cell lymphoma. Epstein-Barr virus (EBV) was not detected by RNA in situ hybridization. Culture for M. tuberculosis was negative. Thus this patient was diagnosed with blastic NK cell lymphoma/leukemia involving bone marrow and lymph node.
Antigens, CD45/metabolism ; Bone Marrow/pathology ; Female ; HLA-DR Antigens/metabolism ; Humans ; Killer Cells, Natural/immunology/*pathology ; Leukemia/*diagnosis/immunology/pathology ; Middle Aged ; Tuberculosis, Lymph Node/diagnosis

BACKGROUND: Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT. METHODS: Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA). RESULTS: Among the lymphocyte subsets, the expression of CD45 was the highest (725,368+/-42,763) on natural killer T (NKT) cells, 674,030+/-48,187 on cytotoxic/suppressor T cells, 588,750+/-48,090 on natural killer (NK) cells, 580,211+/-29,168 on helper T (Th) cells, and 499,436+/-21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells. CONCLUSIONS: NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.
Adult ; Antibodies/immunology ; Antigens, CD45/*analysis/immunology ; B-Lymphocytes/immunology/metabolism ; CD8-Positive T-Lymphocytes/immunology/metabolism ; Female ; Flow Cytometry/*methods ; Fluorescein-5-isothiocyanate/chemistry ; Fluorescent Dyes/chemistry ; Humans ; Killer Cells, Natural/immunology/metabolism ; Lymphocytes/immunology/*metabolism ; Lymphoma/radiotherapy ; Male ; Middle Aged ; Natural Killer T-Cells/immunology/metabolism ; Protein Binding ; Radioimmunotherapy ; Reagent Kits, Diagnostic ; T-Lymphocytes, Helper-Inducer/immunology/metabolism

BACKGROUND: Since the recent introduction of radioimmunotherapy (RIT) using antibodies against cluster of differentiation (CD) 45 for the treatment of lymphoma, the clinical significance of the CD45 antigen has been increasing steadily. Here, we analyzed CD45 expression on lymphocyte subsets using flow cytometry in order to predict the susceptibility of normal lymphocytes to RIT. METHODS: Peripheral blood specimens were collected from 14 healthy individuals aged 25-54 yr. The mean fluorescence intensity (MFI) of the cell surface antigens was measured using a FACSCanto II system (Becton Dickinson Bioscience, USA). MFI values were converted into antibody binding capacity values using a Quantum Simply Cellular microbead kit (Bangs Laboratories, Inc., USA). RESULTS: Among the lymphocyte subsets, the expression of CD45 was the highest (725,368+/-42,763) on natural killer T (NKT) cells, 674,030+/-48,187 on cytotoxic/suppressor T cells, 588,750+/-48,090 on natural killer (NK) cells, 580,211+/-29,168 on helper T (Th) cells, and 499,436+/-21,737 on B cells. The Th cells and NK cells expressed a similar level of CD45 (P=0.502). Forward scatter was the highest in NKT cells (P<0.05), whereas side scatter differed significantly between each of the lymphocyte subsets (P<0.05). CD3 expression was highest in the Th and NKT cells. CONCLUSIONS: NKT cells express the highest levels of CD45 antigen. Therefore, this lymphocyte subset would be most profoundly affected by RIT or pretargeted RIT. The monitoring of this lymphocyte subset during and after RIT should prove helpful.
Adult ; Antibodies/immunology ; Antigens, CD45/*analysis/immunology ; B-Lymphocytes/immunology/metabolism ; CD8-Positive T-Lymphocytes/immunology/metabolism ; Female ; Flow Cytometry/*methods ; Fluorescein-5-isothiocyanate/chemistry ; Fluorescent Dyes/chemistry ; Humans ; Killer Cells, Natural/immunology/metabolism ; Lymphocytes/immunology/*metabolism ; Lymphoma/radiotherapy ; Male ; Middle Aged ; Natural Killer T-Cells/immunology/metabolism ; Protein Binding ; Radioimmunotherapy ; Reagent Kits, Diagnostic ; T-Lymphocytes, Helper-Inducer/immunology/metabolism

Blockade of signal 1 or 2 for T-cell activation by the use of anti-CD45RB and anti-CD154 monoclonal antibodies (mAb) (two-signal blockade) has been proven effective in preventing or delaying graft rejection. However, the mechanisms of its immunomodulatory effects are clearly unknown and the present studies were performed to determine how the two-signal blockade modulate allogeneic immune responses, especially T-cell mediated cellular immunity, in a murine skin allograft model. We now report on the profound inhibition of alloreactive T cells by two-signal blockade via CD4-dependent mechanisms. C57BL/6 mice of BALB/c skin allograft were treated with anti-CD45RB, anti-CD154, CTLA4-Ig, or their combinations. For depletion of CD4 or CD8 T cells, the recipients received CD4-depleting or CD8-depleting mAb. We confirmed that survival of skin allograft was markedly prolongated in the two-signal blockade-treated group. In depletion study, anti-CD45RB, anti-CD154 and CD4-depleting mAb-treated group showed acute rejection of skin allograft in contrast to CD8-depleting group treated with the two-signal blockade. In the group treated with the two-signal blockade, the proportions of CD4+CD45RB(low)and CD8+CTLA-4 regulatory T cells were increased while effector CD8+ T cells, including IFN-gamma-secreting and CD8+CD62L(low)T cells, were decreased when compared with non-treated group. In contrast, the CD4-depleted group treated with the two-signal blockade resulted in recovery from immunoregulatory effects of two-signal blockade. In addition, results of IL-4 and IL-10 production were also showed CD4-dependence. Therefore, the two-signal blockade is accompanied by CD4-dependent mechanisms in allogeneic skin transplantation.
Transplantation, Homologous ; T-Lymphocytes, Regulatory/cytology/immunology ; Skin Transplantation/*immunology ; Signal Transduction/drug effects/immunology ; Mice, Inbred C57BL ; Mice, Inbred BALB C ; Mice ; Male ; Lymphocyte Depletion ; Lymphocyte Activation/immunology ; Interleukin-4/biosynthesis ; Interleukin-10/biosynthesis ; Graft Rejection/*immunology/prevention & control ; Flow Cytometry ; Cytotoxicity, Immunologic/immunology ; CD8-Positive T-Lymphocytes/cytology/immunology/metabolism ; CD40 Ligand/*immunology ; CD4-Positive T-Lymphocytes/cytology/immunology/metabolism ; Antigens, CD45/*immunology ; Antigens, CD4/*immunology ; Antibodies, Monoclonal/administration & dosage/*pharmacology ; Antibodies, Blocking/administration & dosage/pharmacology ; Animals

Recently, subpopulations of regulatory T (Treg) cells, resting Treg (rTreg) and activated Treg (aTreg), have been discovered. The authors investigated the relationship between the change of Treg, aTreg and rTreg and autoimmune diseases. Treg cells and those subpopulations were analyzed by using the human regulatory T cell staining kit and CD45RA surface marker for 42 rheumatoid arthritis (RA), 13 systemic lupus sclerosis (SLE), 7 Behcet's disease (BD), and 22 healthy controls. The proportion of Treg cells was significantly lower in RA (3.8% +/- 1.0%) (P < 0.001) and BD (3.3% +/- 0.5%) (P < 0.01) compared to healthy controls (5.0% +/- 1.3%). The proportion of aTreg cells was also significantly lower in RA (0.4% +/- 0.2%) (P = 0.008) and BD (0.3% +/- 0.1%) (P = 0.013) compared to healthy controls (0.6% +/- 0.3%). The rTreg cells showed no significant differences. The ratio of aTreg to rTreg was lower in RA patients (0.4% +/- 0.2%) than that in healthy controls (0.7% +/- 0.4%) (P = 0.002). This study suggests that the decrement of aTreg not rTreg cells contributes the decrement of total Treg cells in peripheral blood of RA and BD autoimmune diseases. Detailed analysis of Treg subpopulations would be more informative than total Treg cells in investigating mechanism of autoimmune disease.
Adult ; Aged ; Antigens, CD4/metabolism ; Antigens, CD45/metabolism ; Arthritis, Rheumatoid/*immunology/metabolism ; Behcet Syndrome/*immunology/metabolism ; Female ; Forkhead Transcription Factors/metabolism ; Humans ; Interleukin-2 Receptor alpha Subunit/metabolism ; Leukocyte Count ; Lupus Erythematosus, Systemic/*immunology/metabolism ; Male ; Middle Aged ; T-Lymphocytes, Regulatory/*cytology/immunology/metabolism

PURPOSE: Local activation of the complement system plays a role in target organ damage. The aim of our study was to investigate the influence of cyclosporine (CsA)- induced renal injury on the complement system in the kidney. MATERIALS AND METHODS: Mice fed a low salt (0.01%) diet were treated with vehicle (VH, olive oil, 1mL/kg/day) or CsA (30mg/kg/day) for one or four weeks. Induction of chronic CsA nephrotoxicity was evaluated with renal function and histomorphology. Activation of the complement system was assessed through analysis of the expression of C3, C4d, and membrane attack complex (MAC), and the regulatory proteins, CD46 and CD55. CsA treatment induced renal dysfunction and typical morphology (tubulointerstitial inflammation and fibrosis) at four weeks. RESULTS: CsA-induced renal injury was associated with increased the expression of C3, C4d, and MAC (C9 and upregulation of complement regulatory proteins (CD 46 and CD55). Immunohistochemistry revealed that the activated complement components were mainly confined to the injured tubulointerstitium. CONCLUSION: CsA-induced renal injury is associated with activation of the intrarenal complement system.
Animals ; Antigens, CD45/analysis ; Antigens, CD46/analysis ; Antigens, CD55/analysis ; Complement C3/analysis ; Complement C4b/analysis ; Complement Membrane Attack Complex/analysis ; Complement System Proteins/*analysis ; Cyclosporine/*toxicity ; Disease Models, Animal ; Immunity, Innate/drug effects ; Immunoblotting ; Immunohistochemistry ; Immunosuppressive Agents/toxicity ; Kidney/*drug effects/immunology/pathology ; Kidney Diseases/*chemically induced/immunology ; Mice ; Microscopy, Confocal ; Peptide Fragments/analysis