Systemic complement activation following human acute ischaemic stroke

The brain tissue damage after stroke is mediated partly by inflammation induced by ischaemia-reperfusion injury where the complement system plays a pivotal role. In the present study we investigated systemic complement activation and its relation to C-reactive protein (CRP), a known complement activator, and other inflammatory mediators after acute ischaemic stroke. Sequential plasma samples from 11 acute stroke patients were obtained from the time of admittance to hospital and for a follow-up period of 12 months. Nine healthy gender- and age-matched subjects served as controls. The terminal SC5b-9 complement complex (TCC), CRP, soluble adhesion molecules (L-, E- and P- selectin, ICAM, VCAM) and cytokines [tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-8] were analysed. All parameters were within normal values and similar to the controls the first hours after stroke. Terminal complement complex (TCC) increased significantly from 0.54 to 0.74 AU/ml at 72 h (P = 0.032), reached maximum at 7 days (0.90 AU/ml, P < 0.001), was still significantly increased at 12 days (0.70 AU/ml, P = 0.009) and thereafter normalized. CRP increased significantly from 1.02 to 2.11 mg/l at 24 h (P = 0.023), remained significantly increased for 1 week (2.53-2.94 mg/l, P = 0.012-0.017) and thereafter normalized. TCC and C-reactive protein (CRP) correlated significantly (r = 0.36, P < 0.001). The increase in TCC and CRP correlated to the size of infarction (r = 0.80 and P = 0.017 for TCC; r = 0.72 and P = 0.043 for CRP). No significant changes were seen for adhesion molecules and cytokines. In conclusion, transitory systemic complement activation takes place after stroke. The early rise in CRP and the following TCC increase suggest a possible role for CRP in complement activation, which may contribute to inflammation after stroke.     

HIV-induced IL-6/IL-10 dysregulation of CD4 cells is associated with defective B cell help and autoantibody formation against CD4 cells

To analyse CD4 cell cytokine secretion and helper/suppressor function at a clonal level we established 446 CD4⁺ T cell clones (TCC) in four healthy controls, three HIV^? haemophilia patients, four CDC II,III and four CDC IV patients. Spontaneous TCC secretion of Th1 cytokines (IL-2, interferon-gamma (IFN-γ)) and Th2 cytokines (IL-4, IL-6, IL-10) was determined by ELISA. TCC helper and suppressor functions were tested in a pokeweed mitogen (PWM)-stimulated allogeneic co-culture system using a reverse haemolytic plaque assay for assessment of B cell responses. There was a significant association of TCC surface marker expression (Leu-8, CD45RA) with TCC IL-6 secretion in healthy controls (P < 0.01), HIV^? patients (P 0.001) and CDC II,III patients (P 0.01) but not in CDC IV patients. Likewise, TCC expression of Leu-8 and CD45RA was significantly associated with TCC suppressor function in healthy controls (P 0.0005) but not in HIV-infected patients. A reduced TCC helper frequency (10% of TCC) and an enhanced TCC suppressor frequency (> 80% of TCC) were detected only in those HIV-infected patients who showed an excessively increased TCC IL-6 secretion (> 70% of TCC) together with a significantly diminished TCC IL-10 secretion (10% of TCC). CD4 cell autoantibodies also were found only in patients with this type of cytokine dysregulation. These data indicate that CD4 cell surface markers lose their functional relevance in HIV-infected patients. HIV-induced IL-6/IL-10 dysregulation of CD4⁺ T cells, i.e. the up-regulation of spontaneous IL-6 and down-regulation of spontaneous IL-10 secretion, appears to be involved in inducing CD4 helper defects and may promote autoantibody formation against CD4 cells.     

Contact-dependent stimulation of monocytic cells and neutrophils by stimulated human T-cell clones.

By means of direct cell-cell contact, fixed, stimulated T lymphocytes trigger the production of interleukin-1 beta (IL-1 beta) and tumour necrosis factor by monocytes and prime polymorphonuclear leucocytes (PMN) for the respiratory burst induced by N-formyl-methionyl-leucyl-phenylalanine (FMLP). In order to assess whether this activity is displayed by a particular subpopulation of T lymphocytes, 88 T-cell clones (TCC) were generated from healthy human peripheral blood. The clones were stimulated by Phaseolus vulgaris agglutinin (PHA) and phorbol 12-myristate acetate monocytic cell line THP-1. All fixed, stimulated TCC induced IL-1 beta production by THP-1 cells, although to varied degrees. The activity of TCC on THP-1 cells correlated with their activity on PMN (r2 = 0.84, P < 0.001), suggesting that this pro-inflammatory activity of TCC may similarly affect both types of infiltrating cells. The ability of TCC to modulate target cells did not correlate with either their phenotype (CD4 or CD8) or their cytokine production profile (interferon-gamma, IL-4 and IL-6), although it tended to correlate inversely with their capacity to produce IL-6 (P < 0.02). These observations suggest that a large proportion, if not all, of human peripheral blood T lymphocytes may potentially affect monocytes and PMN by direct cell-cell contact. This activity may be relevant to the maintenance of chronic inflammation.     

Complement activation occurs through both classical and alternative pathways prior to onset and resolution of adult respiratory distress syndrome

We have previously reported that plasma concentrations of the terminal complement (C) complex (TCC), C5b-9, increased significantly 2 days prior to onset of adult respiratory distress syndrome (ARDS) and also 1 day preceding its resolution. To determine the pathway of complement activation that preceded development and resolution of this acute inflammatory lung injury in septic patients, we quantified the C1rC1s-C1 inhibitor complex and the C3bP complex, which are generated following activation of classical and alternative complement pathways, respectively. Two days prior to diagnosis of ARDS, the plasma C1rC1s-C1 inhibitor complex and C3bP complex levels increased 22 and 14%, respectively. Furthermore, significant correlations were identified between concentrations of the TCC and C1rC1s-C1 inhibitor complex (r = 0.73, P = 0.003) and also with the levels of the TCC and C3bP complex (r = 0.81, P = 0.002) before onset of ARDS. Equally of interest, the C1rC1s-C1 inhibitor complex and C3bP complex concentrations increased 68 and 35%, respectively, 1 day before resolution of ARDS. Similarly, significant elevations of TCC concentrations preceding resolution of ARDS correlated with C1rC1s-C1 inhibitor complex (r = 0.66, P = 0.02) and also with C3bP complex (r = 0.72, P = 0.002) levels. Our results indicate that both the classical and alternative complement pathways are activated prior to onset of ARDS and also before its resolution in septic patients.     

Reduced IL-10 secretion by CD4+ T lymphocytes expressing mutant cystic fibrosis transmembrane conductance regulator (CFTR)

Expression of the CFTR protein is thought to be physiologically important only in exocrine epithelial cells. However, chronic respiratory inflammation and infection remain unexplained phenomena in disease pathogenesis. Non-transformed, antigen-responsive CD4⁺ T cells cloned from healthy controls and CF patients homozygous or heterozygous for the δF508 mutation transcribed CFTR mRNA and expressed immunoreactive cytoplasmic CFTR protein. T cell clones (TCC) from controls and CF patients displayed equivalent Ca²⁺-mediated Cl⁻ current; however, TCC from patients with CF but not controls displayed defective cAMP-mediated Cl⁻ current. Although CF-derived TCC preserved mitogen and antigen proliferative responses and specificity to tetanus toxoid epitopes, they selectively secreted ≈ 45% less IL-10 compared with control TCC after activation with concanavalin A (Con A) (624 ± 101 versus 1564 ± 401 pg/ml per 10⁶ cells, respectively; P = 0.04) or anti-CD3/phorbol ester (5148 ± 1634 versus 11 788 ± 2390 pg/ml; P = 0.05). This difference was independent of atopy. Secretion of interferon-gamma, IL-2, and IL-4 was comparable in CF and control TCC after both forms of activation, while IL-5 was reduced in CF TCC following anti-CD3/phorbol myristate acetate (PMA) but not after Con A. We conclude that expression of mutant CFTR in human TCC is accompanied by ion channel dysfunction characteristic of the CF phenotype, and is accompanied by a reduction in IL-10 secretion after polyclonal activation. It is possible that disruption of IL-10-mediated anti-inflammatory homeostasis may contribute to early onset sustained inflammation in CF airways.     

Terminal complement complexes and C1/C1 inhibitor complexes in rheumatoid arthritis and other arthritic conditions.

Terminal complement complex (TCC) and C1r-C1s-C1 inhibitor complex (C1/C1 INH) concentrations were measured in plasma and synovial fluid from patients with arthritis and related to other measures of disease activity. Both TCC and C1/C1 INH concentrations were significantly increased in patients with rheumatoid arthritis (RA) compared with patients with osteoarthritis (plasma and synovial fluid, P less than 0.05) and normal subjects (plasma only, P less than 0.001). In the patients with RA, there was no correlation between plasma or synovial fluid TCC concentrations and IgM rheumatoid factor, immune complex or C1/C1 INH levels. However, in 10 patients with seronegative RA, C1/C1 INH and immune complex levels correlated significantly in synovial fluid (r = 0.69, P less than 0.05) although not in plasma (r = 0.52). Plasma and synovial fluid TCC and C1/C1 INH concentrations did not differ in rheumatoid patients with severe compared with mild joint disease (categorized by the Ritchie score). These results confirm a role for complement activation in RA but suggest that several mechanisms are involved in its pathogenesis.     

Complement activation and complement-dependent inflammation by Neisseria meningitidis are independent of lipopolysaccharide

Fulminant meningococcal sepsis has been termed the prototypical lipopolysaccharide (LPS)-mediated gram-negative septic shock. Systemic inflammation by activated complement and cytokines is important in the pathogenesis of this disease. We investigated the involvement of meningococcal LPS in complement activation, complement-dependent inflammatory effects, and cytokine or chemokine production. Whole blood anticoagulated with lepirudin was stimulated with wild-type Neisseria meningitidis H44/76 (LPS+), LPS-deficient N. meningitidis H44/76lpxA (LPS-), or purified meningococcal LPS (NmLPS) at concentrations that were relevant to meningococcal sepsis. Complement activation products, chemokines, and cytokines were measured by enzyme-linked immunosorbent assays, and granulocyte CR3 (CD11b/CD18) upregulation and oxidative burst were measured by flow cytometry. The LPS+ and LPS- N. meningitidis strains both activated complement effectively and to comparable extents. Purified NmLPS, used at a concentration matched to the amount present in whole bacteria, did not induce any complement activation. Both CR3 upregulation and oxidative burst were also induced, independent of LPS. Interleukin-1beta (IL-1beta), tumor necrosis factor alpha, and macrophage inflammatory protein 1alpha production was predominantly dependent on LPS, in contrast to IL-8 production, which was also markedly induced by the LPS- meningococci. In this whole blood model of meningococcal sepsis, complement activation and the immediate complement-dependent inflammatory effects of CR3 upregulation and oxidative burst occurred independent of LPS.     

Terminal complement complex in plasma from patients with systemic lupus erythematosus and other glomerular diseases

To evaluate terminal complement pathway activation in plasma from patients with systemic lupus erythematosus (SLE) and primary glomerular diseases, we developed an enzyme-linked immunosorbent assay (ELISA) for measuring the terminal complement complexes (TCC). The method is based on a sandwich technique using rabbit antibodies against native human C5, C7 and C9. To avoid interference by native components, we equilibrated plasma specimens with 5% polyethylene glycol buffer. The precipitates were measured by ELISA. TCC was detectable in all 14 normal controls (0.48 +/- 0.06 AU/ml; mean +/- s.e.m.). TCC levels were elevated in 18 of 54 patients with SLE (0.89 +/- 0.07 AU/ml; P less than 0.01) and in eight of 11 patients with membranoproliferative glomerulonephritis (MPGN) (3.15 +/- 0.62 AU/ml; P less than 0.01). However, only one of six patients with membranous nephropathy and none of 13 with mesangial proliferative glomerulonephritis showed high values. In SLE, TCC was correlated with circulating immune complexes and inversely with CH50, C3, C4, C5 and alternative complement pathway activity (AH50), and showed significantly high values even in normal CH50 cases (n = 34; P less than 0.01). In MPGN, TCC was inversely correlated with CH50, AH50, C3, C5 and C9. These results suggest that the classical pathway plays an important role for TCC generation in SLE and that the alternative pathway does in MPGN.     

High potential to tumor necrosis factor alpha (TNF-alpha) production of thyroid infiltrating T lymphocytes in Hashimoto's thyroiditis: a peculiar feature of destructive thyroid autoimmunity

T lymphocytes present in thyroid infiltrates of 6 patients with Hashimoto's thyroiditis (HT) and of 4 patients with Graves' disease (GD) were analyzed at clonal level and their profiles of mitogen-induced lymphokine secretion were characterized. Production of interleukin-2 (IL-2), interleukin-4 (IL-4), interferon-gamma (IFN-gamma) was measured in culture supernatants of a total number of 332 T cell clones (TCC) from HT, of 269 TCC from GD infiltrates and of 266 control TCC derived from normal lymphoid tissues. No significant difference was found in the ability to produce IL-2 between TCC from HT or GD infiltrates and control TCC. The proportion of HT- or GD-derived TCC able to produce IL-4 was extremely low (4 and 5%, respectively) in comparison with controls (19%). In contrast, the proportion of interferon-gamma (IFN-gamma)-producing (IFN-P) TCC derived from either HT (87%) or GD (80%) infiltrates was much higher (p less than 0.0005) than that found in controls (59%). In addition, most of IFN-P TCC from either HT or GD usually released higher amounts (p less than 0.002) of IFN-gamma than did control clones. No significant difference was found between GD infiltrates and controls in the proportions of TCC able to secrete TNF-alpha (39% and 47%, respectively), whereas the proportion of TNF-alpha-producing (TNF-P) TCC derived from HT (78%) was significantly higher (p less than 0.0001). In addition, most of both CD8 and CD4 TCC from HT released higher amounts of TNF-alpha than did TNF-P clones from controls or GD. These data suggest that T cells present in autoimmune thyroid infiltrates share a number of functions, such as high production of IFN-gamma, but differ with regard to their ability to secrete TNF-alpha, which is peculiar of most T cells present in the thyroid of HT patients.     

Local and systemic activation of the whole complement cascade in human leukocytoclastic cutaneous vasculitis; C3d,g and terminal complement complex as sensitive markers.

We have studied complement activation both in plasma samples and in lesional skin from patients with leukocytoclastic cutaneous vasculitis (LCV). Enzyme immunoassay (EIA) quantification of the complement activation markers, C3d,g and the terminal complement complex (TCC) in plasma, showed that their levels were significantly increased in 66% and 55% of the patients, respectively (n = 29) compared with healthy controls, whereas the standard measurements of C3, factor B, C1q, C4 and C2 were generally within normal range. Elevations of C3d,g and TCC levels in plasma were significantly correlated. Importantly, a significant correlation was found between the severity of the vasculitis and both C3d,g and TCC plasma levels. Immunofluorescence studies of skin biopsy specimens demonstrated simultaneous presence of perivascular dermal deposits of C3d,g and TCC in lesional skin from 96% and 80% respectively of the patients (n = 25). There was a significant correlation between the intensity of the deposits of both markers. Clusterin, a TCC inhibitory protein, was always found at the same sites of perivascular TCC deposits. Immunofluorescence studies at the epidermal basement membrane zone (BMZ) revealed in each case deposits of C3d,g which were accompanied by TCC deposits in 52% of the biopsy specimens. These data demonstrate that there is a local and systemic activation of the whole complement cascade in human LCV. The presence of both C3d,g and clusterin-associated TCC perivascular deposits suggests an intervention of a regulatory mechanism of local complement activation in LCV. Finally, measurement of plasma C3d,g and TCC appears to be a sensitive indicator of systemic complement activation and disease severity in LCV.     

Transient elevation of interleukin-16 levels at the initial stage of meningitis in children

IL-16 is an immunomodulatory cytokine that is characterized by chemotactic activity and stimulation of proinflammatory cytokine expression in monocytic cells. We studied IL-16 using ELISA in children with meningitis. When meningeal symptoms existed, IL-16 levels were high in the cerebrospinal fluid (CSF) of both bacterial (939 +/- 877 ng/l, n = 20) and aseptic (341 +/- 371 ng/l, n = 23) meningitis. The values in the CSF were significantly higher than those in non-meningitis controls (29 +/- 8 ng/l, n = 22, P < 0.0001). After meningeal symptoms disappeared, IL-16 levels in bacterial (191 +/- 149 ng/l, n = 10, P = 0.0042) and aseptic (159 +/- 188 ng/l, n = 13, P = 0.0118) meningitis were lower than those during the symptomatic stage. IL-16 levels were the highest before day 5 of the illness and then gradually fell. Significant correlations were found between IL-16 levels and both G-CSF levels (r = 0.783, n = 11, p = 0.0029) and IL-6 levels (r = 0.818, n = 12, P = 0.0005) in the CSF of bacterial and aseptic meningitis. IL-16 levels in all CSF samples from non-meningitis controls were lower than those in serum. In contrast, IL-16 levels in the CSF in six of 16 samples from bacterial meningitis and two of 18 samples from aseptic meningitis were higher than those in serum. Serum levels of IL-16 did not fluctuate throughout the course of meningitis. These data indicate that IL-16 levels rise transiently in CSF at the initial stage of meningitis. We speculate that IL-16 may promote inflammatory responses during meningitis in concert with other proinflammatory cytokines.     

Activation of the Complement, Coagulation, Fibrinolytic and Kallikrein–Kinin Systems During Attacks of Hereditary Angioedema

Five patients with hereditary angioedema (HAE) were studied during attacks and remission as were healthy controls. The high levels of C1/C1-INH complexes, low C4 and high ratio C4 activation products (C4bc)/C4 also differed significantly during remission compared to controls.During attacks C4bc/C4 increased (922–2007; P =0.022, remission versus attacks, median values throughout), C2 and CH50 dropped (111–31%; P =0.043 and 110–36%; P =0.016, respectively), TCC (C5b-9) increased (0.88–1.23 AU/ml; P =0.028). Cleavage of HK increased to be almost complete during attacks (20–90%; P =0.009). While factor XIa/serpin-complexes did not increase, a more than twofold rise in thrombin/antithrombin-complexes (0.20–0.50 μg/l; P =0.009) and in plasmin/alpha-2-antiplasmin-complexes (7.3–17 nmol/l; P =0.028) was observed. For the first time cascade activation in HAE was studied simultaneously, and corroborates that attacks lead to activation of the kallikrein-kinin system, fibrinolysis and early part of the classical complement pathway. In addition, the authors present novel data of terminal complement and coagulation activation, the latter apparently not via FXIa.     

肥胖患者氧化应激和脂肪细胞因子变化

目的:研究男性单纯肥胖患者氧化应激(OS)和脂肪细胞因子变化及相互关系.方法:测定42例男性肥胖患者和32例健康非肥胖男性个体的血8-异前列腺素F2α(8-iso-PCF2α)、血浆超氧化物歧化酶(SOD)、血清丙二醛(MDA)、脂联素、瘦素、抵抗素、人肿瘤坏死因子可溶性受体1(TNF-R1)、白介素-1β(IL-1β)、白介素-6(IL-6).结果:肥胖患者8-iso-PGF2α、MDA、瘦素、TNF-RI、IL-1β和IL-6均明显高于正常对照组(P<0.05,P<0.01),脂联素和SOD均明显低于正常对照组(P<0.05,P<0.01),2组抵抗素水平无统计学意义(P>0.05).肥胖组相关分析:8-iso-PGF2α与BMI(r=0.54,P<0.05)呈正相关,与脂联素(r=-0.56,P<0.05)呈负相关,瘦素与体脂(r=-0.53,P<0.05)呈负相关,脂联素与LDL(r=-0.54,P<0.05)和IL-6(r=-0.41,P<0.05)呈负相关.多元逐步回归分析:脂联素和IL-6是影响肥胖患者OS变化的主要因素.结论:男性单纯肥胖患者存在OS和脂肪细胞因子变化,脂肪细胞因子与OS存在明显的相关性.     

慢性肾炎患者血浆leptin和血清IL-6、EL-18及SOD检测的临床意义

目的：探讨慢性肾炎患者治疗前后血浆leptin和血清IL-6、IL．18及SOD水平的变化及临床意义。方法：应用放射免疫分析和酶联免疫法对33例慢性肾炎患者进行了血浆leptin和血清IL-6、IL．18及SOD检测,并与35名正常健康人作比较。结果：慢性肾炎患者在治疗前血浆leptin和血清IL-6、IL．18均显着地高于正常人组（P〈0．01）,而血清SOD水平则显着地低于正常人组（P〈0．01）。经中西医结合治疗3个月后与正常人组比较仍有显著性差异（P〈0．05）,血浆leptin水平与血清IL-6、IL．18水平呈正相关（r=0．5718、0．4916,P〈0．01）,而与SOD水平呈负相关（r=-0．6018,P〈0．01）。结论：检测慢性肾炎患者治疗前后血浆leptin和血清IL-6、IL-18及SOD水平的变化对临床观察和预后有重要的临床价值。     

Ethnic differences in plasma levels of interleukin-8 (IL-8) and granulocyte colony stimulating factor (G-CSF)

Ethnic neutropenia is common in people of African descent. As interleukin-8 (IL-8) and granulocyte colony stimulating factor (G-CSF) bind to receptors on neutrophils, ethnic differences in neutrophil counts are hypothesized to result in different plasma levels of these cytokines. A prospective study was conducted in 72 healthy young volunteers. Neutrophil counts were 60% higher in Caucasians (P<0.00001). Average IL-8 and G-CSF levels were about 50% and 70% higher in African volunteers compared with Caucasian volunteers (P=0.0008 and P=0.00005, respectively). Additionally, oxidative burst capacity in stimulated neutrophils was significantly lower in volunteers of African descent (P=0.03 between both groups). In sum, lower neutrophil counts are associated with higher levels of IL-8 and G-CSF in Africans.     

IL-1B and IL-6 gene polymorphisms encode significant risk for the development of recurrent aphthous stomatitis (RAS)

Recurrent aphthous stomatitis (RAS) is an, ulcerative condition of the mouth, with a polygenic mode of inheritance in which cytokines are thought to play an important role. Ninety-one RAS patients and 91 controls were genotyped for known IL-1A, IL-1B, IL-1RN and IL-6 gene polymorphisms. Inheritance of the G allele of the IL-1B -511 polymorphism was strongly associated with RAS (OR = 2.5, P < 0.00002), with increased numbers of G/G homozygotes (OR = 4.5, P < 0.0005). The G allele of IL-6 -174 also occurred more frequently in RAS (OR = 2.6, P < 0.0001) with greatest risk associated with G/G homozygosity (OR = 3.4, P < 0.0001). IL-1RN VNTR 1/1 homozygotes also occurred more frequently in RAS (OR = 2.0, P < 0.02). Inheritance of the G/G genotype of both IL-1B and IL-6 was a particularly strong predictor for RAS (OR = 8.5).     

Alternative pathway activation of complement in laparoscopic and open rectal surgery

The study was designed to investigate whether complement is activated in patients subject to rectal surgery and whether the choice of surgical technique (open or laparoscopic) has any impact on the activation of complement. Our hypothesis is that laparoscopic surgery leads to a lower-level activation of complement than open surgery. Patients (n = 24) subject to rectal surgery owing to rectal cancer were included. The study was prospective and randomized. The patients were randomized to either laparoscopic surgery (n = 12) or open surgery (n = 12). Blood samples for determination of complement activation (C4d, Bb, C3bc and the terminal C5b-9 complex TCC) were drawn before start of surgery (T0) and at the following time-points after start of surgery: 180 min (T1), 360 min (T2), 24 h (T3) and 3-5 days (T4). A significant increase in the alternative pathway activation product Bb and in the terminal pathway activation product TCC was seen over time in both groups (P < 0.001). Bb peaked early (T1) and returned to baseline levels post-operatively, whereas TCC increased steadily with maximum values in the late post-operative period. The plasma concentrations of C4d and C3bc decreased significantly in both groups at T1 and T2 and returned to baseline levels at T4. There was no significant difference between the groups. Rectal surgery causes activation of the complement system. Complement is activated through the alternative pathway. Results mostly showed no significant differences between laparoscopic and open rectal surgery apart from lower levels of factor Bb in the former group in the perioperative period.     

Influence of major surgery on the mannan-binding lectin pathway of innate immunity

The mannan-binding lectin (MBL) pathway of complement activation is important in host defence against pathogens and possibly against cancer. We investigated the effect of major surgery on two central components of the MBL pathway; MBL and the MBL-associated serine protease MASP-2, and for comparison also measured the interleukin (IL)-6 and C-reactive protein (CRP) levels. Serial blood samples were obtained from patients belonging to two different cohorts. Cohort 1 comprised 60 patients undergoing open or laparoscopic colectomy for benign disease (n = 12) or colon cancer (n = 48). Cohort 2 comprised 27 patients undergoing elective, open surgery for colorectal cancer, and was included in order to cover blood sampling between days 2 and 6. As expected, the surgical stress induced a marked acute phase response, as evidenced by a large increase in IL-6 (18-fold) and CRP (13-fold) levels with maximum at 12 h and 2 days, respectively. However, in both cohorts the levels of MBL and MBL-associated serine protease 2 (MASP-2) were largely unaffected, except for a minor but significant increase around day 8 in cohort 1. The preoperative levels of IL-6 and CRP were correlated significantly in both cohorts (r = 0.71, P < 0.0001 and r = 0.65, P = 0.005, respectively). Preoperative MASP-2 correlated with preoperative CRP (r = 0.59, P = 0.001) and IL-6 (r = 0.55, P = 0.02) in cohort 2 only. In contrast to the marked effects on the levels of IL-6 and CRP, the surgery influenced only marginally the two proteins of the MBL pathway.     

Complement activation patterns in atypical haemolytic uraemic syndrome during acute phase and in remission

Atypical haemolytic uraemic syndrome (aHUS) is associated with (genetic) alterations in alternative complement pathway. Nevertheless, comprehensive evidence that the complement system in aHUS patients is more prone to activation is still lacking. Therefore, we performed a thorough analysis of complement activation in acute phase and in remission of this disease. Complement activation patterns of the aHUS patients in acute phase and in remission were compared to those of healthy controls. Background levels of complement activation products C3b/c, C3bBbP and terminal complement complex (TCC) were measured using enzyme‐linked immunosorbent assay (ELISA) in ethylenediamine tetraacetic acid (EDTA) plasma. In vitro‐triggered complement activation in serum samples was studied using zymosan‐coating and pathway‐specific assay. Furthermore, efficiencies of the C3b/c, C3bBbP and TCC generation in fluid phase during spontaneous activation were analysed. Patients with acute aHUS showed elevated levels of C3b/c (P < 0·01), C3bBbP (P < 0·0001) and TCC (P < 0·0001) in EDTA plasma, while values of patients in remission were normal, compared to those of healthy controls. Using data from a single aHUS patient with complement factor B mutation we illustrated normalization of complement activation during aHUS recovery. Serum samples from patients in remission showed normal in vitro patterns of complement activation and demonstrated normal kinetics of complement activation in the fluid phase. Our data indicate that while aHUS patients have clearly activated complement in acute phase of the disease, this is not the case in remission of aHUS. This knowledge provides important insight into complement regulation in aHUS and may have an impact on monitoring of these patients, particularly when using complement inhibition therapy.     

Dysregulated production of interleukin-8 in individuals infected with human immunodeficiency virus type 1 and Mycobacterium tuberculosis

Interleukin-8 (IL-8) production in vivo was monitored in four study groups: normal blood donors, patients with pulmonary tuberculosis (TB), patients with human immunodeficiency virus type 1 (HIV-1) infection, and dually infected (HIV/TB) patients. We show that whereas there was evidence of detectable levels of cell-associated IL-8 (mRNA and protein) in peripheral cells of healthy individuals, this was largely lost in the disease states studied. Coupled with this finding was significantly increased circulating levels of IL-8 in HIV-1-infected individuals with or without concomitant pulmonary TB (P < 0.001). On the other hand, the capacity of peripheral mononuclear cells to produce IL-8 spontaneously ex vivo was enhanced in HIV-1 and TB patients (P < 0.05) and many of the HIV/TB group, but their corresponding capacities to respond to various stimuli, in particular phytohemagglutinin, were significantly diminished compared to those of normal donors (P < 0.05). Circulating levels of IL-8 in a group of HIV/TB patients were significantly positively correlated with the percentage of polymorphonuclear leukocytes (PMN) in the peripheral circulation (r = 0.65; P = 0.01), the proportions of IL-8 receptor A (IL-8RA)-expressing (r = 0.86; P < 0.01) and IL-8RB-expressing (r = 0.77; P < 0.01) PMN, and the capacity of PMN to migrate in response to IL-8 as chemoattractant (r = 0.68; P < 0. 01). IL-8RB fluorescence intensity, however, was negatively correlated with plasma IL-8 levels (r = -0.73; P < 0.01). Our results suggest that altered regulation of IL-8 in HIV-1 may have important implications for antimicrobial defenses and for normal immune processes.