Differential diagnostic significance of the paucity of HLA-I antigens on metastatic breast carcinoma cells in effusions.
(9/1648)
Distinction between benign reactive mesothelial cells and metastatic breast adenocarcinoma cells in effusions from patients with a known prior history of breast cancer is not the easiest task in diagnostic pathology. Here, we report the usefulness of testing the expression of class I HLA antigens (HLA A, B, C) in this respect. Cytospins were prepared from effusions of patients without the history of breast cancer (5 cases) and from effusions of patients with infiltrating ductal carcinoma (11 cases). Three effusions from cancerous patients were not malignant cytologically. The expression of HLA-A, B, C, HLA-DR and beta2-microglobulin as well as the macrophage antigen, CD14, was evaluated by immunocytochemistry. In 10 of 11 effusions the cytologically malignant cells expressed very weak or undetectable HLA-A,B,C as compared to the mesothelial cells and macrophages. The paucity of expression of HLA-A, B, C was detectable in those 3 cases where a definitive cytological diagnosis of malignancy could not be established. In contrast, mesothelial cells and macrophages from all samples were uniformly and strongly positive for both HLA-A, B, C and beta2-microglobulin. We conclude that the paucity of HLA-I antigens provides a marker helpful in distinguishing metastatic breast carcinoma cells from reactive mesothelial cells in effusions. (+info)
Early harvest and late transplantation as an effective therapeutic strategy in multiple myeloma.
(10/1648)
Transplantation after high-dose chemotherapy prolongs survival in patients with multiple myeloma compared with standard therapy. It is unclear whether the optimal timing of transplantation is immediately after induction chemotherapy or whether stem cells may be cryopreserved for transplantation at subsequent progression or relapse. In this study, stem cells were collected within 6 months of diagnosis, followed by transplantation only at progression of myeloma. One hundred and eighteen patients with multiple myeloma had stem cells collected and cryopreserved. Eleven had transplants early in the disease after they demonstrated failure to respond to primary therapy. The remaining 107 were eligible for transplants when there was evidence of progressive disease. Of the 118 patients, 67 had transplants, nine died of progressive disease before transplantation, and 42 remain alive in plateau phase. The median survival of the group is 58.5 months; 67 are alive. Serum beta2-microglobulin, bone marrow labeling index (S phase), and hemoglobin level predicted overall survival (P < 0.006, P < 0.001, and P < 0.01, respectively). We conclude that early cryopreservation of blood stem cells followed by transplantation at progression is a feasible approach to therapy in patients with myeloma. The underlying biology of the disease has a greater impact on survival than the timing of transplantation. A prospective randomized trial is required to answer definitively the question of the optimal timing of blood cell transplantation. (+info)
Biochemical characterization of CD1d expression in the absence of beta2-microglobulin.
(11/1648)
CD1d is a major histocompatibility complex class I-like molecule that exhibits a distinct antigen processing pathway that functions in the presentation of hydrophobic antigens to T cells. CD1d has been previously shown to be expressed on the cell surface of human intestinal epithelial cell lines in vivo and a transfected cell line in vitro independently of beta2-microglobulin (beta2m). To define the relationship between CD1d and beta2m and characterize the biochemical structure of CD1d in the absence of beta2m, we have used a newly generated series of CD1d transfectants and CD1d-specific antibodies. These studies show that in the absence of beta2m, CD1d is expressed on the cell surface as a 45-kDa glycoprotein that is sensitive to endoglycosidase-H and is reduced to 37-kDa after N-glycanase digestion. In contrast, in the presence of beta2m, CD1d is expressed on the cell surface as a 48-kDa endoglycosidase-H-resistant glycoprotein. Pulse-chase metabolic labeling studies demonstrate that acquisition of endoglycosidase-H resistance of CD1d is observed in the presence of beta2m but not in the absence of beta2m even after a 24-h chase period. Thus, CD1d is able to be transported to the cell surface independently of beta2m; however, in the absence of beta2m, the glycosylation pattern of CD1d is altered and consistent with an immature glycoprotein. (+info)
CD86 (B7-2) can function to drive MHC-restricted antigen-specific CTL responses in vivo.
(12/1648)
Activation of T cells requires both TCR-specific ligation by direct contact with peptide Ag-MHC complexes and coligation of the B7 family of ligands through CD28/CTLA-4 on the T cell surface. We recently reported that coadministration of CD86 cDNA along with DNA encoding HIV-1 Ags i.m. dramatically increased Ag-specific CTL responses. We investigated whether the bone marrow-derived professional APCs or muscle cells were responsible for the enhancement of CTL responses following CD86 coadministration. Accordingly, we analyzed CTL induction in bone marrow chimeras. These chimeras are capable of generating functional viral-specific CTLs against vaccinia virus and therefore represent a useful model system to study APC/T cell function in vivo. In vaccinated chimeras, we observed that only CD86 + Ag + MHC class I results in 1) detectable CTLs following in vitro restimulation, 2) detectable direct CTLs, 3) enhanced IFN-gamma production in an Ag-specific manner, and 4) dramatic tissue invasion of T cells. These results support that CD86 plays a central role in CTL induction in vivo, enabling non-bone marrow-derived cells to prime CTLs, a property previously associated solely with bone marrow-derived APCs. (+info)
Clinico-biological implications of increased serum levels of interleukin-8 in B-cell chronic lymphocytic leukemia.
(13/1648)
BACKGROUND AND OBJECTIVE: Constitutive cellular expression and serum release of biologically active interleukin-8 (IL-8) has been reported in B-cell chronic lymphocytic leukemia (CLL). Given the autocrine role played by IL-8 in the process of cell accumulation characteristic of this disease we tried to investigate clinico-biological implications of increased serum levels of this cytokine in an unselected series of B-cell CLL patients. DESIGN AND METHODS: Serum levels of IL-8 were determined at the time of diagnosis in 58 previously untreated B-CLL patients using an immunoenzyme assay. Results were correlated with main clinico-hematologic features as well as with the risk of disease progression. Finally, we looked for associations between IL-8 and molecules directly involved in apoptosis, such as intracellular bcl-2 and soluble APO-1/Fas. RESULTS: Increased serum levels of IL-8 were found in 15 out of 58 (25.8%) B-cell CLL patients. Serum levels of IL-8 did not reflect clinico-biological features representative of tumor mass such as clinical stage, histopathologic pattern of bone marrow (BM) involvement, b2-microglobulin, sCD23 and sCD27 titers. Interestingly, circulating levels of IL-8 paralleled those of intracellular bcl-2 (r = 0.522; p = 0.01), thus confirming that the antiapoptotic effect of IL-8 can be exerted through a bcl-2 dependent pathway. Levels of IL-8 did not match those of soluble Apo-1/Fas (r = -0.013; p = 0.943). Finally, stage A patients with levels of IL-8 above the median value (i.e. 4.5 pg/mL) were more likely to progress to a more advanced clinical stage than those with levels below the median value (p < 0.05). INTERPRETATION AND CONCLUSIONS: IL-8 is an interesting marker in B-cell CLL, closely involved in the pathogenesis of disease. Furthermore, it is useful for predicting the pace of disease progression in early clinical stages. (+info)
Peritoneal clearance of leptin in CAPD patients: impact of local insulin administration.
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INTRODUCTION: The ob gene product leptin is secreted by fat cells and the serum leptin levels reflects the body fat content. Markedly elevated serum leptin levels have been reported in patients with chronic renal failure. The aim of the present study was to assess if the dialysate leptin levels in peritoneal dialysate are similar to what can be expected from passive diffusion or if intraperitoneal synthesis of leptin may occur. METHODS: We studied 39 patients (20 males), mean age 54+/-12 years, who had been treated with peritoneal dialysis for 17+/-12 months. Ten of the patients were diabetics of which seven used intraperitoneal insulin. A 24-h collection of dialysate was performed and dialysate and fasting blood samples were analysed for leptin, albumin and beta2-microglobulin, and the peritoneal clearances (PCl) were calculated for these solutes. RESULTS: Serum leptin (mean 47+/-76, range 3-350 ng/ml) was related to body mass index (r=0.35, P<0.05). In multiple regression analysis, serum leptin also correlated to serum TNF-alpha. Although dialysate leptin levels correlated to serum leptin, they were higher than expected from the molecular weight of 16 kD. PCl of leptin was 1.3 ml/min (range 0.2-5.9 ml/min), which was 1.6 times higher than expected from the molecular weight of leptin and PCl for albumin and beta2-microglobulin, not taking the protein binding of leptin into account. A strong correlation was found between PCI for albumin and beta2-microglobulin (r = 0.68, P < 0.0001) but neither PCl albumin, nor PCl beta2-microglobulin correlated to PCI leptin. The PCl of leptin was markedly higher in diabetics using intraperitoneal insulin (n = 7) compared to the other 32 patients (2.6+/-2.0 vs 1.1+/-0.7 ml/min, P<0.05). CONCLUSION: Serum leptin is locally produced in the peritoneal cavity, and intraperitoneal insulin enhances local production of leptin. (+info)
TAP association influences the conformation of nascent MHC class I molecules.
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The influence of TAP-MHC class I interactions on peptide binding to the class I heavy chain is assessed during TAP-dependent assembly using Kb-specific Abs that recognize conformational changes induced by assembly with beta2-microglobulin (beta2m) and by peptide binding. A significant portion (45%) of Kb molecules in TAP+, RMA-derived microsomes are associated with the TAP complex as measured by coimmunoisolation of Kb using anti-TAP1 Abs, while only 20% of the Kb heavy chain molecules are isolated as Kbbeta2m complexes with the alpha-Kb-specific Abs, Y-3 or K-10-56. The amount of Kb isolated with Y-3 and K-10-56 increases in proportion to transport and binding of peptide to the Kb molecules within the RMA microsomes. In contrast, less than 5% of the Kb within TAP2-RMA-S microsomes associated with the remaining TAP1 subunit. However, greater than 60% of Kb heavy chain is isolated as K-10-56- and Y-3-reactive Kbbeta2m complexes. We propose that a TAP-MHC class I interaction serves to stabilize the MHC class I:beta2m complex in an immature conformation (Y-3 and K-10-56 nonreactive) prior to high affinity peptide binding, preventing the export of class I molecules complexed with low affinity peptide ligands from the ER. (+info)
Crystal structure of human ZAG, a fat-depleting factor related to MHC molecules.
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Zn-alpha2-glycoprotein (ZAG) is a soluble protein that is present in serum and other body fluids. ZAG stimulates lipid degradation in adipocytes and causes the extensive fat losses associated with some advanced cancers. The 2.8 angstrom crystal structure of ZAG resembles a class I major histocompatibility complex (MHC) heavy chain, but ZAG does not bind the class I light chain beta2-microglobulin. The ZAG structure includes a large groove analogous to class I MHC peptide binding grooves. Instead of a peptide, the ZAG groove contains a nonpeptidic compound that may be implicated in lipid catabolism under normal or pathological conditions. (+info)