Infections with hepatitis B and C viruses in patients on maintenance dialysis in Romania and in former communist countries: yellow spots on a blank map?

We studied prospectively, between 1993 and 1998, the prevalence and incidence of markers against hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV), in 180 patients with chronic renal failure, dialysed in the Nephrological Clinic, Cluj. HBV and HCV markers were common in the patients who were already on haemodialysis in 1993 (antibodies to hepatitis B core antigen [HBcAb]: 57.9-88%; hepatitis B surface antigen [HBsAg]: 8.7-25%; antibodies to HCV [anti-HCV]: 73.7-100%; simultaneous occurrence of HBsAg and anti-HCV antibodies: 4.4-21%). These patients had the longest mean duration of haemodialysis therapy (6.79 +/- 4.82 years). The lowest prevalence was found in 1996, in the groups of patients included in the haemodialysis programme between 1993 and 1996 (HBcAb: 2.2-3.3%; HBsAg: 0-2.2%; anti-HCV antibodies: 0-2.2%; HBsAg and anti-HCV antibodies: 0-2.2%). The patients included since 1996 had, again, a high prevalence of markers (HBsAg: 21.6%; anti-HCV antibodies: 28.6%), despite the short duration of dialysis therapy (1.65 +/- 1.18 years). The incidence of infection was high before 1993, fell markedly between 1993 and 1996 (zero for the HBsAg and 6. 67% year-1 for the anti-HCV antibodies) and rose sharply between 1996 and 1998 (10.2%, respectively 29% year-1). The prevalence of HBV and HCV infections did not correlate with the age of the patients and depended, but only up to 1993, on the quantity of transfused blood. The link between the duration of the haemodialysis and the prevalence of the HBV and/or HCV infection proved nosocomial transmission. The very high prevalence and incidence of HBV and HCV infections, surpassing not only Western countries, but even those of 'developing' countries that are endemic for these infections, is characteristic of some former communist countries. A radical reform of the medical system in these countries is required.

[Factors in the progression of renal insufficiency during the 2 years preceding the use of dialysis]. / Facteurs de progression de l'insuffisance rénale dans les deux ans précédant la mise en dialyse.

UNLABELLED: The respective contribution of sex, type of nephropathy, degree of proteinuria, blood pressure, protein and sodium daily intake, lipid profile, protidemia, hemoglobinemia, acidosis and CaPO4 product on the rate of renal failure progression is debated. The link between these parameters and the decrease of creatinine clearance, delta Ccr (according to Cockroft) was assessed in uni and multivariate analysis in a population of 49 patients (26 men, 23 women; age 60 +/- 15 years, weight 73 +/- 15 kg) selected out of 173 presently treated hemodialysis patients on the basis of availability of a quarterly follow-up for two years before starting dialysis. The patients were advised a moderate protein and salt restriction which could be retrospectively assessed (on urinary excretion of urea and sodium) at respectively 0.82 g/kg/day and 6.5 g/day. The two years delta Ccr was 14 +/- 14 ml/min. It was not different in men and women (specially when expressed in % of initial value). This decrease in Ccr was neither significantly different in glomerular disease (17 +/- 8, n = 14), diabetic nephropathy (12 +/- 6, n = 7), nephroangiosclerosis (15 +/- 8, n = 5), interstitial nephritis (12 +/- 10, n = 14), and PKD (11 +/- 12, n = 9). Patients with antihypertensive drugs (n = 42) had a faster progression than those without drugs (n = 7): delta Ccr = 15 +/- 14 vs 7 +/- 7 ml/min (p < 0.05) in spite of comparable blood pressure but with higher proteinuria. Linear regression of delta Ccr with the initial and two year averaged values of the quantitative parameters showed a significant positive link for both values with cholesterol, hemoglobin and proteinuria and a negative one with protidemia. A positive link was observed with the initial value of bicarbonate and the two year mean of diastolic and mean blood pressures. No link at all was observed with urea and Na excretion, CaPO4 product and triglycerides. Multiple regression disclosed a significant link only for protidemia (negative with both initial and two years averaged value), diastolic BP (only for the two year averaged value and hemoglobinemia (for the initial value). When the patients were classified according to a threshold value of their protidemia, DBP, hemoglobinemia, and cholesterolemia those with the combination of two risk factors of progression (pro-tidemia < 66 g/l, DBP > or = 90 mmHg, hemoglobinemia > 11 g/dl, proteinuria > 3g/d, CT > 5 mmol/l) had a significantly greater decrease of Ccr than those with the three other combinations at the exception of the association of low protidemia with DBP. CONCLUSION: 1. diastolic hypertension and low protidemia are the two most important factors predicting progression of renal failure; 2. a predictive synergy was furthermore pointed out between on one hand low protidemia and diastolic hypertension and on the other hand proteinuria and cholesterol; 3. on the contrary, anemia attenuates progression linked to low protidemia, diastolic hypertension, proteinuria and high cholesterol.

Divergent effects of Fc gamma RIIIA ligands on the functional activities of human natural killer cells in vitro.

The Fc gamma receptor (R)IIIA (CD 16) plays an important role in regulating the cytotoxic and non-cytotoxic functions of human natural killer (NK) cells. Some anti-CD 16 monoclonal antibodies (mAb) have been shown to stimulate NK activity, while human monomeric (m) IgG induces dose-dependent inhibition of NK activity. To explore further these interactions mediated via Fc gamma RIIIA, purified NK cells were cultured for 2-3 days in the presence of mIgG, 3G8 mAb, interleukin-2 (IL-2) or a combination of mIgG or 3G8 with IL-2. Binding of mIgG or 3G8 to Fc gamma RIIIA induced divergent effects of functions of cultured NK cells: 3G8 mAb + IL-2 induced dose-dependent inhibition of proliferation attributable to apoptosis; in contrast, mIgG + IL-2 significantly increased NK cell proliferation. Incubation of NK cells in the presence of mIgG up-regulated expression of surface activation markers (CD69, IL-2R alpha, ICAM-1), cytotoxicity, cytokine production (IL-1 beta, IFN-gamma and TNF-alpha) and release of soluble IL-2R. Thus, mIgG binding to Fc gamma RIIIA induced stimulatory signals in human NK cells, leading to up-regulation of IL-2R alpha expression, cell proliferation and cytokine release.

Abortion prohibition and acute renal failure: the tragic Romanian experience.

During the period 1966-1989, pregnancy interruption was severely punished in Romania. However, natality rose only temporarily, while illegal abortions reached at least 3.36%/year and became the main etiology of ARF. From the 653 patients hemodialyzed for ARF during 1979-1989 in Cluj, 131 (20.07%) had abortions; during 1990-1993 only 3 (1.52%) had this diagnosis. Of the women with postabortion ARF, 71.64% were oligoanuric. The average duration of oligoanuria was 18.9 days, the longest reversible oligoanuria 89 days, the mean schedule of dialysis 1/2.98 days. Hysterectomy was performed in 44.3%; chronic renal failure occurred in 8.21% of the patients. Mortality rate averaged 14.92%, being greater in hysterectomized women (18.64%) and in those with a BUN over 150 mg% at admission. The survivors had to face the menace of imprisonment and the interrogation of prosecutors already in the hospital, regardless of their health problems.

Natural killer (NK) activity in human responders and nonresponders to stimulation by anti-CD16 antibodies.

Various anti-Fc gamma RIII (CD16) monoclonal antibodies (mAbs) are shown here to have positive or negative modulatory effects on human NK cells. Thus, 3G8 mAb (IgG1) triggered a dose-dependent augmentation of NK activity in 67% (23/34) of individuals tested, who were designated as responders. All four IgG1 anti-CD16 mAb tested (BL-LGL/1, B73.1, Leu11c, and 3G8) were stimulatory for NK cells isolated from responders, whereas six non-IgG1 anti-CD16 mAbs were either inhibitory or had no significant effects on NK activity. The upregulation of NK activity in responders was not attributable to an increase in either the conjugate formation or the delivery of the lethal hit to target cells. This mAb-mediated up-regulation of NK activity was shown to be associated with a recycling capacity higher than that of controls and with enhanced release of cytokines by activated NK cells. Anti-CD16 mAb inhibited binding of either monomeric or polymeric IgG to Fc gamma RIIIA on NK cells. Also, mAb 3G8 or its F(ab')2 fragments decreased or reversed inhibition of NK activity induced by monomeric IgG (mIgG). Our data indicate that regulation of NK activity via the Fc gamma RIIIA is influenced by dose-dependent interactions between cytophilic mIgG and anti-CD16 mAb of IgG1 isotype.

Effect of interleukin-2 on the monomeric IgG-induced inhibition of human natural killer cell activity.

Monomeric IgG (mIgG) has been previously shown to inhibit human natural killer (NK) cell activity when effector cells were treated prior to the cytotoxic assay. In the present study the interaction between negative regulation by mIgG and positive regulation by interleukin-2 (IL-2) was examined. Although a dose-dependent boosting of NK activity was found upon incubation of nonadherent lymphocytes (NAL) with recombinant or natural IL-2 for 2 h at 37 degrees C, the NK effector cells remained responsive to down-regulation to mIgG. However, when NAL were treated with IL-2 under supraoptimal conditions (higher doses and longer periods of incubation than required for optimal boosting of NK activity) the subsequent addition of mIgG had a significantly reduced inhibitory effect. This partial resistance to suppression by inhibitory IgG was observed only when the second treatment was performed without washing the IL-2-pretreated effector cells. Moreover, addition of antihuman interferon gamma antibodies during the incubation of NAL with IL-2 almost abolished the loss of responsiveness of the IL-2-activated killer cells to mIgG-induced inhibition. These data provide additional evidence for the ability of interferon gamma to reverse or block the down-regulation of NK activity by mIgG.

Regulation of human natural cytotoxicity by IgG. III. Interaction between negative regulation by monomeric IgG and positive regulation by interferons of different types.

Our prior reported results have demonstrated the dose-dependent inhibition of human natural killer (NK) cell activity upon treatment of peripheral blood mononuclear cells (PBMC) with monomeric IgG (mIgG) prior to the cytotoxic assay. In the present study, the combined effects on NK activity of human interferon (IFN) of each of the three types and mIgG, respectively, were determined. NK cells incubated with IFN alpha or IFN beta had augmented cytotoxicity against K562 target cells but remained responsive to negative regulation by mIgG. PBMC treated with human recombinant IFN gamma had unchanged cytotoxic activity but became partially resistant to suppression by mIgG. This ability of IFN gamma to interfere with the negative regulation of NK activity by cytophilic mIgG was seen when the cytokine was preincubated with effector cells prior to, simultaneously with, or after their exposure to inhibitor protein. These data provide some clues regarding the possible biological significance of the mIgG-induced down-regulation of NK cells which, when required for host protection, might be appreciably reversed or blocked by IFN gamma produced by NK cells or T cells in response to various agents.

Regulation of human natural cytotoxicity by IgG. II. Cyclic AMP as a mediator of monomeric IgG-induced inhibition of natural killer cell activity.

In this study we investigated the mechanism of inhibition of NK activity by monomeric IgG (mIgG) and the enhancement of inhibition induced by 3-isobutyl-1-methylxanthine (IBMX) or theophylline (TP) as inhibitors of cyclic nucleotide phosphodiesterase, or by prostaglandin E2 (PGE2) as an activator of adenyl cyclase. Human peripheral blood mononuclear cells (PBMN) and nonadherent lymphocytes (NAL) were treated with various concentrations of mIgG, IBMX, TP, PGE2, either alone, or in combination. The treatments were done before and/or during the cytotoxicity assay against 51chromium-labeled K562 target cells. Combined pretreatment with mIgG and treatment during the assay with IBMX or TP induced much more inhibition than that induced by either treatment alone. At some concentrations of each agent, additive inhibition was observed, whereas at other concentrations, synergistic effects were seen. With the combination of PGE2 and mIgG, an additive inhibitory effect could be seen only at very low concentrations of PGE2, due to its strong inhibitory potency. Although endogenous PGE2 released during preincubation at 37 degrees C by adherent PBMN led to some reduction of NK activity, experiments with indomethacin indicated that mIgG-induced inhibition of spontaneous cytotoxicity was not dependent on its presence. The intracellular levels of cyclic AMP in highly purified NK cells were increased after pretreatment with mIgG and even higher levels were measured when IBMX was also added to the effector cells. Taken together, our data provide evidence that mIgG-induced inhibition of NK cells is mediated at least partially by cyclic AMP.

Regulation of human natural cytotoxicity by IgG--I. Characterization of the structural site on monomeric IgG responsible for inhibiting natural killer cell activity.

Inhibition of human natural killer (NK) cell activity upon exposure of peripheral blood lymphocytes (PBL) to IgG in monomeric form (mIgG) was found to be dose-, time- and temp-dependent. PBL incubated for 2 hr at 37 degrees C in the presence of myeloma protein of a certain class or subclass had a significant reduction of their NK activity when exposed to IgG, but not to IgM or IgD, and the IgG-induced inhibition of NK cells was observed only when IgG1 or IgG3 paraproteins were used. IgG3 isolated from normal serum had a higher inhibitory property than that of total mIgG. The cytophilic activity of the IgG molecules was confined entirely to the Fc region and seemed to be localized in the CH3 domain, since human and rabbit Facb fragments had a reduced ability to inhibit NK activity. When synthetic peptides representing various sequences of the human gamma-chain were tested for inhibition of NK activity, only treatment of effector cells with a peptide comprising the sequence Tyr407-Arg416 of the CH3 domain showed a reduction of NK cell function comparable to the inhibition obtained following incubation of cells in the presence of mIgG. However, on a molar basis, this peptide was 20 times less active than mIgG. In contrast, peptides derived from sequences in the CH2 domain lacked this inhibitory capacity. Our data indicate that the structural site responsible for inhibiting NK cell activity is located in the C-terminal domain of the IgG molecule.

Immunologic alterations associated with chronic hemodialysis.

Parameters of humoral immunity were studied in 18 patients with chronic renal failure undergoing hemodialysis. IgG, IgA and IgM serum levels presented no differences compared with healthy donors. High immunoglobulins levels were found in 40 patients with chronic renal failure and conservative treatment. Complement components C1q, C4, C9, were normal, but C3 and C3A were significantly low prior to dialysis. During hemodialysis, the complement system showed an activation by the alternative pathway (AP). The cuprophan membrane was proved to be an important factor in this activation. The circulating immune complexes (CIC) were also high. Seven patients presented autoantibodies, 2 against smooth muscle and 5 against gastric parietal cells. Our results suggested a certain humoral immune alteration during chronic hemodialysis.

Inhibition of human natural killer cell activity by cytophilic immunoglobulin G.

The natural killer (NK) cell activity of human peripheral blood mononuclear cells (PBL) was found to be increased after incubation at 37 degrees C for 2 hr. The observed increase was shown to be associated with release from inhibition by human serum factors, because incubation in autologous serum interfered with augmentation. The serum-mediated effect appeared attributable to the degree of binding of labile IgG to PBL and could be reduced by selective depletion of IgG from the serum. Human monomeric IgG was found to efficiently inhibit the culture-induced augmentation of NK activity; the inhibitory IgG had properties consistent with those described for cytophilic IgG and was mediated through the Fc region of IgG. The inhibition by monomeric IgG occurred at 0 degrees C as well as at 37 degrees C and this could be induced even after culture-induced augmentation of NK activity. Thus, binding of monomeric IgG to human PBL appears to reversibly inhibit their NK activity. These results provide evidence for a novel mechanism for negative regulation of NK activity.

IgG-binding sites on macrophage cell membrane. II. Mobility of Fc receptors induced by the interaction with their corresponding IgG ligands.

Mouse peritoneal macrophages were charged with IgG molecules in monomeric (mIgG), heat-aggregated (agIgG) or antigen-complexed (acIgG) form. Upon exposure to 37 degrees C, all bound IgG ligand types are redistributed on the cell surface due to the mobilization of their corresponding Fc receptor (FcR). The major findings regarding the fate of FcR on macrophages bearing IgG ligands are as follows: (a) the FcR involved in the binding of cytophilic molecules has a slow movement on the cell membrane and forms patches but never caps, while the opsonic type of FcR is rapidly capped; (b) the mobility of IgG-binding sites was temperature-dependent and was affected differently by sodium azide; this metabolic inhibitor enhances the disappearance of mIgG from the cell surface but decreases the capping and the disappearance of polymeric ligands; (c) both FcR types are probably ingested when complexed with specific ligand, and consequently, the rebinding of homologous IgG molecules is reduced, the clearing induced by agIgG or acIgG binding being much more extensive; and (d) cells cleared of their opsonic types of FcR are able to regenerate the receptor molecules with 8 h of incubation at 37 degrees C.

IgG-binding sites on macrophage cell membrane. I. Identification of two distinct Fc receptors on mouse peritoneal macrophages.

Evidence is presented concerning the existence on mouse peritoneal macrophages of two separate and distinct Fc receptors, one for cytophilic monomeric IgG (mIgG) and the other for polymeric IgG. The latter Fc receptor recognizes both heat-aggregated IgG and antigen-complexed IgG. The major findings of our studies are: (a) the different susceptibility of the two Fc receptor types by pronase, trypsin or phospholipase C; (b) the independent modulation of these two binding sites on the cell membrane; (c) the inability of mIgG to inhibit the binding of particulate antigen-complexed IgG ligand; (d) the ability of mIgG molecules which are devoid of the cytophilic property to attach to the macrophage surface upon their polymerization induced by heating or antigen. The results are discussed in terms of "cytophilic" and "opsonic" Fc receptor types which may provide different functional abilities for normal macrophages.

Effect of cell density on the disappearance of cell surface immunoglobulins.

Mouse macrophages and human peripheral blood lymphocytes exhibiting on the membrane autologous IgG as well as mouse thymocytes coated with human IgG, showed a strong cell concentration dependence of surface IgG disappearance during an incubation at 37 degrees C. Mouse spleen lymphocytes treated with anti-mouse Ig behaved in the same way regarding the disappearance of surface immunoglobulins, while the redistribution of ligands (cap formation) was not dependent on cell concentration.