CD3+ leukemic large granular lymphocytes utilize diverse T-cell receptor V beta genes

CD3+ large granular lymphocyte (LGL) leukemia is a disease of unknown etiology characterized by clonal proliferation of T cells that usually express T-cell receptor (TCR) alpha beta heterodimers. The purpose of this study was to identify the variable (V), joining (J), and diversity (D) region TCR beta-chain genes expressed by CD3+ LGL leukemic cells in an attempt to gain insights into the etiology of this disorder. Twelve patients with LGL leukemia were studied, including seven with both LGL leukemia and rheumatoid arthritis (RA). RA is also a disease of unknown etiology that occurs frequently in patients with LGL leukemia. Clonally expanded T cells that express specific TCR V beta genes have been identified in fluid and tissue specimens from the joints of patients with RA. In this study, V beta expression was determined by PCR using a panel of 22 unique V beta primers to amplify cDNA prepared from peripheral blood mononuclear cells (PBMC). A dominant V beta gene product was readily apparent in all patients. To confirm that the dominant V beta gene originated from a clonal expansion, DNA fragments corresponding to the dominant V beta genes were subcloned into plasmids and independently isolated recombinants were sequenced. V-D-J region sequences that occurred repeatedly indicated clonality. The V beta and J beta genes expressed by the leukemic cells showed a pattern of distribution that followed the frequency with which these genes are represented in the peripheral blood. The residues corresponding to the third complementarity-determining region of the TCR beta chain were different in all cases. A specific pattern of VDJ usage was not identified for those patients with both LGL leukemia and RA; however, utilization of V beta-6 by LGL clones (N = 3) was observed only in the setting of RA. These data suggest that leukemic CD3+ LGL cells have been clonally transformed in a random fashion with respect to the TCR beta chain.     

Induction of NK activity in large granular lymphocyte leukemia: activation with anti-CD3 monoclonal antibody and interleukin 2

Large granular lymphocyte (LGL) leukemia is a rare disease characterized by clonal expansion of LGL associated with chronic neutropenia, multiple auto-antibodies, and occasionally polyarthritis. We studied cell surface antigen expression and functional activity of leukemic LGL from ten such patients. Using two-color flow cytometric analysis, we found that leukemic LGL from all ten patients expressed the CD3 and HNK-1 markers, while cells from only four patients expressed IgG Fc receptors (FcR). The LGL leukemic cells had little or no NK activity (defined as MHC-nonrestricted cytotoxicity against K562 target cells); however, NK activity could be induced in leukemic LGL by in vitro treatment with as little as 0.05 microgram/mL of anti-CD3 monoclonal antibody. Cell sorting experiments demonstrated that NK activity was induced in CD3+ leukemic LGL (either CD3+, HNK-1+ or CD3+, FcR+) with anti-CD3 monoclonal antibody but not in normal CD3+, FcR- T cells. Treatment with purified interleukin 2 (IL 2) also caused direct activation of some CD3+ leukemic LGL. Despite induction with anti-CD3 MAb or IL 2, activated leukemic LGL did not proliferate or express high density IL 2 receptors detectable by cell sorter analysis. Treatment with alpha interferon had minimal effect on NK activity of LGL leukemic cells. These results suggest that leukemic LGL may provide a useful model for examining the signals required for LGL maturation and activation.     

Effects of the selective aldosterone blocker eplerenone versus the calcium antagonist amlodipine in systolic hypertension

Eplerenone is a highly selective aldosterone blocker, which is under development for the treatment of hypertension and heart failure. To assess its usefulness in older patients with systolic hypertension and widened pulse pressure, we compared the effects of eplerenone with amlodipine, on clinic blood pressure (BP) and pulse pressure and in a subset of the patients, ambulatory BP, vascular compliance, and urinary albumin excretion. The study involved 269 patients > or =50 years of age who were randomly assigned to either eplerenone (50 to 200 mg daily) or amlodipine (2.5 to 10 mg daily) in a double-blind titration to effect design. After 24 weeks of therapy, reductions in clinic systolic BP were similar for both treatments (eplerenone, -20.5+/-1.1 mm Hg; amlodipine, -20.1+/-1.1 mm Hg). Reductions in clinic diastolic BP were modestly larger on amlodipine (-6.9+/-0.7 mm Hg) compared with eplerenone (-4.5+/-0.7 mm Hg) (P=0.014). Pulse pressure was also reduced similarly from baseline by the 2 treatment groups (eplerenone, -15.9 mm Hg versus amlodipine, -13.4 mm Hg, P=0.07). Changes from baseline in pulse wave velocity after 24 weeks of therapy were statistically similar for eplerenone and amlodipine. In patients with microalbuminuria at baseline (>30 mg albumin/g creatinine), eplerenone reduced the urinary albumin/creatinine ratio by 52% compared with a reduction of 10% by amlodipine (P=0.04). Thus, eplerenone was as effective as amlodipine in lowering systolic BP and pulse pressure as well as pulse wave velocity in older patients with widened pulse pressure hypertension. Furthermore, eplerenone reduced microalbuminuria to a greater extent than amlodipine in this older patient group.     

Mitochondrial oxidative stress contributes differently to rat pancreatic islet cell apoptosis and insulin secretory defects after prolonged culture in a low non-stimulating glucose concentration

Aims/hypothesis  

Pancreatic beta cells chronically exposed to low glucose concentrations show signs of oxidative stress, loss of glucose-stimulated insulin secretion (GSIS) and increased apoptosis. Our aim was to confirm the role of mitochondrial oxidative stress in rat islet cell apoptosis under these culture conditions and to evaluate whether its reduction similarly improves survival and GSIS.     

Use of cyclical etidronate and prevention of non-vertebral fractures

This study examined the effects of cyclical etidronate, when used in routine clinical practice, on the prevention of fracture. Information was obtained from 550 general practices in the UK that provide their medical records to the General Practice Research Database. A total of 7977 patients taking cyclical etidronate treatment and 7977 age-, sex- and practice-matched control patients with a diagnosis of osteoporosis were analysed. People taking cyclical etidronate had a significantly reduced risk of non-vertebral fracture (by 20%) and of hip fracture (by 34%) relative to the osteoporosis control patients. The relative risk of non-vertebral fracture was 0.80 (95% confidence interval 0.70-0.92), that of hip fracture 0.66 (0.51-0.85) and that of wrist fracture 0.81 (0.58-1.14). When fracture incidence rates were compared between the two groups, the rate of non-vertebral, hip and wrist fracture decreased significantly (P < 0.05) with increasing etidronate exposure. The results of this study complement and extend clinical observations supporting the anti-fracture efficacy of cyclical etidronate therapy.      

Influence of isosorbide dinitrate on superior mesenteric artery impedance in humans

Summary In a randomized, double-blind, placebo-controlled crossover study the acute effect of isosorbide dinitrate (ISDN) on the superior mesenteric artery velocity waveform was studied in 10 healthy subjects (mean age 48.2 years) over a 10-minute period. The superior mesenteric artery pulsatility index (PI), which quantifies the blood velocity waveform, increased from the second minute following sublingual administration of 5 mg ISDN (basal PI 4.88±0.32) and reached its upper level (8.22±1.38) from the fourth minute on. In comparison with placebo, the significant rise of PI (second minute) occurred before the significant decrease of systolic blood pressure (ninth minute) and before the significant increase in the heart rate (fourth minute). Diastolic and mean arterial blood pressures remained unchanged. These observations suggest an immediate vasoconstrictive effect of ISDN on the resistance vessels of the vascular bed of the superior mesenteric artery.     

Clonal diseases of large granular lymphocytes [see comments]

Three distinct clinical syndromes occur in patients with increased numbers of circulating LGL. Patients with T-LGL leukemia have clonal proliferations of CD3+ LGL typically associated with chronic neutropenia and autoimmune features. NK-LGL leukemia is characterized by clonal CD3- LGL proliferation with an acute clinical presentation marked by massive hepatosplenomegaly and systemic illness. However, most patients with increased numbers of CD3- LGL do not have clinical features of NK-LGL leukemia and have a chronic clinical course. X- linked gene analyses have supported a polyclonal LGL lymphocytosis in this syndrome. Further studies are needed to determine whether clonal progression can occur in these patients.     

Prevention of degradation of human polymorphonuclear leukocyte proteins by diisopropylfluorophosphate

Proteases can complicate the characterization of proteins from cells, especially human polymorphonuclear leukocytes (PMN), which contain abundant neutral proteases. We tested the ability of agents to inhibit proteolysis, with special reference to the subunit polypeptides of the contractile proteins actin, myosin, and actin-binding protein (ABP). Phenylmethylsulfonyl fluoride (PMSF), O-phenanthroline, EGTA, EDTA, N- ethylmaleimide, alone or in combinations, failed to prevent extensive proteolysis of the PMN proteins during solubilization of cells with dodecyl sulfate. These inhibitors and also alpha-1-antitrypsin and soybean trypsin inhibitor similarly could not prevent proteolysis during homogenization of cells in cold isosomolar sucrose. Treatment of PMN with greater than or equal to mM diisopropylfluorophosphate (DFP) prior to solubilization or homogenization markedly inhibited proteolysis. PMSF and DFP were equally effective in inhibiting proteolysis in PMN extracts, suggesting that the efficacy of DFP may result from its permeation of intact cells and granules before barriers are disrupted by detergents or homogenization. Treatment of PMN with DFP under conditions inhibiting proteolysis did not affect their rate of phagocytosis. We recommend the use of DFP in future studies correlating functions and protein structure of PMN.     

Sublocalisation of the X breakpoint in the translocation (X; 18)(p11.2; q11.2) primary change in synovial sarcomas

A specific translocation between chromosomes X and 18 was identified in synovial sarcomas. From a girl with synovial sarcoma, we isolated two clones with t(X; 18)(p11.2; q11.2) and which had lost the normal X chromosome. Southern blot analysis of DNA from the tumor, the patient and her parents demonstrated that the normal X chromosome, lost in the tumor, was the paternal one. A somatic hybrid cell line was established by fusing tumor cells (after passages on athymic mice) to an HPRT deficient hamster cell line. By cytogenetic, in situ hybridization and molecular analysis, it was found to contain the derivative (X) chromosome in the absence of the der (18) chromosome. To determine the position of the breakpoint on the X chromosome, Southern blots of DNA from this hybrid were hybridized to [32P]-labelled X chromosome probes. DXS146 and DXS255 were retained in the hybrid cell line whereas GAPDP1, the ARAF1 and TIMP proto-oncogenes were not present, indicating that the breakpoint lies proximal to GAPD1, ARAF1 and TIMP and distal to DXS255 and DXS146. Results obtained from other authors are compared. Further studies will be necessary to determine the extent of variation of the breakpoint in different tumors.