There are only few clinical studies on complement in well-defined (or characterized) paediatric HIV patients. Aim of this study was to evaluate the complement system and immunoglobulins in HIV-infected children and to correlate data to stage of disease. Blood samples of 127 HIV-infected children (11-134 months; 62 male : 65 female) were collected in order to evaluate humoral immunity. The patients were classified according to CDC clinical (N-asymptomatic; A-mild symptoms such as common recurrent infections; B-moderate symptoms such as Candidiasis and herpes infections, meningitis, sepsis and anaemia; C-severe symptoms such as opportunistic infections and neoplasia) and with respect to immunological criteria (T CD4(+) cell count). Analysis of complement system included the classical (CH50), alternative (APH50) pathway activities and plasma concentrations of mannan-binding lectin (MBL), of the C4 allotypic variants C4A and C4B. (ELISA), and of the C3 split product C3d (rocket immunoeletrophoresis). Immunodiagnosis also included CD4(+) and CD8(+) lymphocyte count and immunoglobulin concentrations. Complement activation and consumption was observed in all patients correlating with disease activity. Activated classical and alternative pathways and elevated C3d were significantly correlated with immunologic category 3. C3d levels were also significantly correlated with immunologic category 1. Undetectable CH50 and APH50 were found in two (group C) and 10 patients (n = 2, A = 2, B = 2, C = 4), respectively. Low MBL values were found in 13/127 but without correlation to disease severity. Undetectable C4B levels were observed in three patients, favouring the diagnosis of a complete deficiency. Although not related to clinical symptomatology, a strong ongoing complement activation can be observed in all stages of HIV infection. In contrast to earlier reports MBL could not be considered as a risk factor for HIV.

Background/Aims: Apoptosis is a key event in the pathophysiology of many liver diseases. Primary human hepatocytes (PHH) provide a useful model to study physiological and pathophysiological processes in the liver. Our aim was to optimize PHH cultures to allow studies on induction of apoptosis and of hepatitis B virus (HBV) infection.Methods: PHH were isolated from human liver tissue by two-step collagenase perfusion. PHH and hepatoma cells were treated with different apoptosis-inducing agents in parallel. PHH cultures were infected with wild type HBV and transduced with HBV genomes using adenoviral vectors.Results: PHH were successfully isolated from 40 different tissue samples with high viability and purity. Perfusion time and seeding density turned out to be critical parameters for optimal cell yield and culture conditions, respectively. Serum addition to the medium reduced viability of PHH. PHH allowed reproducible studies of CD95-dependent and-independent apoptosis. Sensitivity towards CD95-mediated apoptosis was markedly higher than in hepatoma cells. PHH could efficiently be infected with HBV, but infection did neither induce apoptosis nor prevent CD95-induced cell death.Conclusions: Our data show that PHH provide an excellent tool for the investigation of apoptosis induced by agents like death receptor-ligands and hepatotropic viruses. (C) 2003 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.

Excessive activation of the protein cascade systems often leads to severe inflammatory tissue destruction with potential life-threatening outcome. These include clinical disorders, such as capillary leak syndrome, septic shock, myocardial infarction and other ischaemia/reperfusion injuries, trauma, burns, multiple organ failure, as well as graft rejection. A therapeutic substitution of appropriate regulators appears to be a reasonable approach to reduce undesirable inflammatory reactions. C1-inhibitor, a multifunctional regulator of the various kinin-generating cascade systems, is frequently reduced in patients suffering from severe inflammation. C1-inhibitor concentrate has been used for decades as a substitution therapy to treat acute attacks in patients with hereditary angioedema. Studies including pathophysiologically relevant animal models now provide sufficient evidence that C1-inhibitor may also serve as an effective means to protect against inflammatory tissue injury. Promising clinical results are emerging which support C1-inhibitor as a candidate for therapy in severe inflammatory disorders. Although treatment with C1-inhibitor is regarded as safe, recent reports on possible side effects in certain clinical situations emphasise the importance of controlled clinical studies. The following review will focus on the impact of C1-inhibitor treatment on diseases, where complement contributes to the pathogenesis.

Complement plays a decisive role in postischemic tissue injury, a process responsible for severe damage after organ ischemia. Several pathophysiologic mechanisms initiated upon reperfusion are mediated by complement inducing micro-circulatory disturbances. Here, we demonstrate the effects of complement inhibition using C1-esterase inhibitor (C1-INH) on microcirculation after liver ischemia by invivo microscopy (IVM). In rats, the left liver lobe was clamped for 70 min. C1-INH was given 1 min prior to reperfusion. Controls received Ringer's solution. IVM was performed 30-100 min after reperfusion. Non-perfused acini decreased and sinusoidal perfusion increased substantially after treatment. Leukocyte adherence to sinusoidal and venular endothelium was markedly reduced by C1-INH. Transaminases were significantly decreased by C1-INH. Our data obtained by IVM suggest that complement activation is an early key event of ischemia/reperfusion injury. These observations demonstrate for the first time that reperfusion related microcirculatory disorders can be minimized by C1-INH. This compound should be evaluated in clinical application.

Background: Recent observations provide evidence that the complement system is involved in the pathophysiology of ischemia/reperfusion injury. Methods: In this study we assessed the impact of complement inhibition on hepatic microcirculation by in vivo microscopy (IVM) using a rat model of warm hepatic ischemia. Therefore the left liver lobe was clamped for 70 min. 12 animals received the physiological complement regulator C1-Esterase-Inhibitor (C1-Inh) intravenously 1 min prior to reperfusion, This component blocks the classical pathway of the complement cascade. First clinical trials showed a beneficial effect in cases of capillary leak syndromes, especially angioedema. Controls received an equal amount of Ringer's solution (n = 12). Microvascular perfusion and leukocyte-endothelial cell interaction were studied 30 to 100 min after reperfusion by IVM. Results: Microvascular perfusion in hepatic sinusoids was improved in the C1-Inh group (90% +/- 2.2 vs. 71.9% +/- 3.3; p < 0.001). The number of adherent leukocytes was reduced in sinusoids (96.5 +/- 13.7 vs. 198.8 +/- 20 [adherent leukocytes per mm(2) liver surface]; p < 0.001) as well as in postsinusoidal venules after sCR1 treatment (129.4 +/- 12.2 vs. 366.1 +/- 31.9 [adherent leukocytes per mm2 endothelial surface]; p < 0.001). Plasmatic liver enzyme activity was decreased significantly upon C1-Inh treatment, indicating reduced parenchymal cell injury. Conclusion: Our results provide further evidence that the complement system plays a decisive role in hepatic ischemia/reperfusion injury. Based on our results we conclude that complement inhibition by C1-Inh represents an effective treatment to prevent reperfusion injury in warm organ ischemia not restricted to the liver.