Laboratory Diagnosis and Clinical Profile of Anti-p200 Pemphigoid

IMPORTANCE

Anti-p200 pemphigoid is a rare subepidermal autoimmune blistering disease characterized by autoantibodies against a 200-kDa protein in the basement membrane zone. Anti-p200 pemphigoid is probably often misdiagnosed because of low availability of diagnostic assays and expertise and classified as bullous pemphigoid or epidermolysis bullosa acquisita.

OBJECTIVE

To clinically characterize patients with anti-p200 pemphigoid, identified by using indirect immunofluorescence microscopy on skin substrates deficient in type VII collagen and laminin-332 (knockout analysis), to validate this technique by immunoblot with dermal extract, and to incorporate direct immunofluorescence serration pattern analysis in the diagnostic algorithm.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective study performed from January 2014 to June 2015 with biobank patient materials and clinical data for the period 1998 to 2015 from the single national referral center on autoimmune bullous diseases. Patients were selected based on a dermal side binding on 1-mol/L salt (sodium chloride)-split human skin substrate by indirect immunofluorescence microscopy, not diagnosed epidermolysis bullosa acquisita or anti-laminin-332 mucous membrane pemphigoid.

MAIN OUTCOMES AND MEASURES

Indirect immunofluorescence microscopy knockout analysis was performed and diagnosis of anti-p200 confirmed by immunoblot with dermal extract. Clinical, histological, and immunological findings were registered. Autoantibodies against laminin γ1 were determined by immunoblot.

RESULTS

Twelve patients with anti-p200 pemphigoid (7 male and 5 female; mean age, 66.6 years) were identified using the indirect immunofluorescence microscopy knockout analysis. Direct immunofluorescence microscopy showed a linear n-serrated IgG deposition pattern along the basement membrane zone in 9 of 11 patients. The diagnosis was confirmed by immunoblot showing autoantibodies against 200-kDa protein in dermal extract in 12 of 12 patients. Autoantibodies against recombinant laminin γ1 were detected by immunoblot in 8 of 12 patients. Remarkable similarities were seen in clinical features with predominantly tense blisters on hands and feet, resembling dyshidrosiform pemphigoid. Mucosal involvement was seen in 6 (50%) of the patients.

CONCLUSIONS AND RELEVANCE

Predominance of blisters on hands and feet may be a clinical clue to the diagnosis of anti-p200 pemphigoid. Direct immunofluorescence microscopy serration pattern analysis and indirect immunofluorescence microscopy knockout analysis are valuable additional techniques to facilitate the diagnosis of anti-p200 pemphigoid.

[Expressions of complement C1q and C3c in rat brain tissues with cerebral ischemia/reperfusion injury]

OBJECTIVE

To observe the expression levels of the complement fragment C1q and C3c in rat brain tissues with cerebral ischemia-reperfusion (I/R) injury, and explore the correlation, roles and mechanism of complement reaction and microglia in the brain I/R injury.

METHODS

A total of 48 male Sprague-Dawley rats were randomly divided into normal control group, sham group, I/R 24 h, 72 h, 7 d, 15 d model groups. Suture occlusion method was operated to establish focal middle cerebral artery occlusion (MCAO) and reperfusion models. The Nissl staining was applied to observe the structure of neurons, and immunohistochemistry was applied to detect CD11b, C1q and C3c expression.

RESULTS

Compared with the sham group, Nissl staining reaction in brain tissues was stronger in the I/R 24 h group, and then became weaker, and the reduction was the most significant in the I/R 72 h group. The expression of CD11b protein increased in the I/R 24 h group and reached the peak value in the I/R 72 h group, followed by gradually reducing. Compared with the sham group, all the model groups were significantly stronger in CD11b expression (P<0.05). C1q and C3c sharply increased in the brain tissue of I/R 24 h group and peaked in the I/R 7 d group, and then presented a downward trend; the differences between the sham group and all the model groups were of statistical significance (P<0.05).

CONCLUSION

The expression levels of C1q and C3c are positively correlated with CD11b protein in rat brain tissues with cerebral I/R injury, suggesting that cerebral I/R injury inintiate the brain innate immune response, activates complement C1q and C3c as well as microglia, thus playing the role of protection or damage in cerebral I/R injury.

Serum proteins in chronic hepatitis B patients treated with peginterferon alfa-2b

AIM: To study the differential protein profile in serum of hepatitis B patients.

METHODS: Serum samples were obtained from patients with chronic hepatitis B who were receiving peginterferon alfa-2b. The serum samples were subjected to albumin depletion and analyzed by two-dimensional gel electrophoresis (2-DE). Differentially expressed protein spots were identified by electrospray ionization-quadrupole time-of-flight mass spectrometry. Alpha-2-HS-glycoprotein, complement component C3c and CD5 antigen were further analyzed by an enzyme-linked immunosorbent assay and immunonephelometry.

RESULTS: Nineteen patients with HBeAg-positive chronic hepatitis B (CHB) were studied. These patients were followed for at least 1 year after treatment and were classified according to their treatment response: responders (n = 9) and non-responders (n = 10). 2-DE and MS/MS analysis were performed to compare the serum proteins before initiating peginterferon alfa-2b. From the quantitative analysis of the 2-D gel, 7 proteins were detected between the two groups at different levels before treatment. Among these potential candidates, serum levels of alpha-2-HS-glycoprotein, complement component C3c and CD5 antigen-like precursor were further analyzed. In the validation phase, 23 subjects, 9 sustained responders and 14 non-responders, were recruited. Interestingly, the levels of alpha-2-HS-glycoprotein and complement component C3c were elevated in the serum of the non-responders compared to the responders.

CONCLUSION: Serum alpha-2-HS-glycoprotein and complement component C3c may be potential serum biomarkers in predicting the treatment response of peginterferon alfa-2b in patients with CHB prior to treatment.

Levels of complement components iC3b, C3c, C4, and SC5b-9 in peritoneal fluid and serum of infertile women with endometriosis

OBJECTIVE

To assess whether complement components iC3b, C3c, C4, and SC5b-9 may be involved in the pathogenesis of endometriosis.

DESIGN

Prospective, experimental trial.

SETTING

Medical university.

PATIENT(S)

112 women infertile women undergoing laparoscopy.

INTERVENTION(S)

Venipuncture and laparoscopic peritoneal fluid collection.

MAIN OUTCOME MEASURE(S)

Peritoneal fluid and serum iC3b, C3c, C4, and SC5b-9 levels were measured by the enzyme-linked immunosorbent assay (ELISA) method.

RESULT(S)

Higher levels of C3c, C4, and SC5b-9 complement components were found in the serum compared with the peritoneal fluid, but the levels of iC3b were higher in the peritoneal fluid. We observed higher concentrations of C3c, C4, and SC5b-9 in the peritoneal fluid and serum of women with endometriosis compared with healthy women. However, the levels of iC3b in both peritoneal fluid and serum were statistically significantly lower than in the control group.

CONCLUSION(S)

The impairment of the mechanisms involved in the regulation of activation of complement system may be an important factor in the pathogenesis of endometriosis and endometriosis-associated infertility.

Glomerular C3c deposition and intravascular macrophage accumulation in early humoral renal allograft rejection signifies a poor short-term outcome

C4d deposition in the walls of peritubular capillaries is considered the key phenomenon in the histopathological diagnosis of humoral, i.e. antibody-mediated, allograft rejection. We have earlier proposed that deposition of C3c in glomerular capillaries and simultaneous intravascular accumulation of macrophages in allografts with immediate or early humoral rejection indicates a potentially serious condition with very poor prognosis. The clinical outcome of 45 cadaveric grafts with this phenomenon among 1960 renal allografts transplanted at our centre during 1984-1999, and the recipients of the contralateral kidneys, was retrospectively evaluated. Graft failure occurred in 44/45 grafts within 3 weeks, with graft loss in 33/45 (77%) within 4 months and 37/45 (82%) within 1 year. From the contralateral kidneys, 5/33 (15%) were lost within 1 year. In a recent series of early biopsies, we recognised that of 13 cases showing C4d positivity in peritubular capillaries but lacking C3c in glomeruli, 10/13 (77%) were still functioning after 4 months. The mean number of CD68(+) macrophages per glomerular profile, i.e. the glomerular macrophage index, shows a significant difference between C4d(+)C3c(-) and C4d(+)C3c(+) cases (p<0.001). Our results indicate the existence of a clinically important subgroup of early humoral rejection with particular morphological features.

Complement C3c and related protein biomarkers in amyotrophic lateral sclerosis and Parkinson's disease

We have used quantitative 2D gel electrophoresis to analyze serum proteins from 422 patients with neurodegenerative diseases and normal individuals in an unbiased approach to identify biomarkers. Differences in abnormal serum levels were found between amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD), and related disorders for 34 protein biomarker spots, nine of which were related to the complement system. Of these nine, four spots originated from the Complement C3b-alpha-chain (C3c(1), C3c(2a), C3c(2b), and C3dg). The C3c spots (C3c(1), C3c(2a), and C3c(2b)) had the same amino acid sequence and glycosylation, though only C3c(1) was phosphorylated. In addition, Complement Factors H, Bb, and Pre-Serum amyloid protein displayed different serum concentrations in ALS, PD, and normal sera, whereas Complement C4b gamma-chain and Complement Factor I did not. The differential expression of the complement proteins provides potentially useful biomarkers as well as evidence for the involvement of inflammatory processes in the pathogenesis of ALS and PD.

Glomerular deposition and urinary excretion of complement factor H in idiopathic membranous nephropathy

BACKGROUND/AIMS

The complement system plays an important role in the pathogenesis of membranous nephropathy (MN). In order to elucidate the regulatory mechanism of complement activation, we demonstrated glomerular deposition and urinary excretion of complement factor H, which controls the alternative pathway and the amplification loop at the C3 step, in patients with idiopathic MN.

METHODS

Renal biopsy specimens from 20 patients with idiopathic MN were studied immunohistochemically using monoclonal antibodies against complement components including factor H. SDS-PAGE and Western blotting analysis of urine samples were performed, and the urinary excretion of factor H and C5b-9 were measured by quantitative sandwich ELISA.

RESULTS

Intense glomerular deposition of factor H was observed with C3b.C3c and C5b-9 at an early stage of the disease. Factor H was detected in Western blots of urine samples, but factor H-like protein 1 (FHL-1) was not. The mean level of urinary factor H was elevated (86.30 +/- 21.93 U/mg urinary creatinine) in comparison to that of normal controls (4.76 +/- 1.03 U/mg urinary creatinine). Urinary factor H level exhibited no correlation with clinical parameters; however, a negative correlation was found between urinary C5b-9/factor H and creatinine clearance (r = 0.662, p < 0.01).

CONCLUSION

The source of glomerular and urinary factor H is supposedly a 150-kD protein. There was no evidence to suggest that FHL-1 is synthesized at the site of inflammation. The urinary C5b-9 to urinary factor H ratio is indicative of the degree of ongoing complement activation in the glomeruli and complement-mediated renal injury. These findings suggest that factor H contributes to the control mechanism of in situ complement activation and prevents renal damage in idiopathic MN.

Immunoperoxidase versus immunofluorescence in the assessment of human renal biopsies

BACKGROUND

For half a century, immunofluorescence (IF) on frozen sections has been the gold standard for immunohistochemical evaluation of renal biopsy specimens. In routine diagnostic immunohistopathologic evaluation, traditional IF has been replaced to a large extent by immunoperoxidase (IP) methods applied to paraffin sections of formaldehyde-fixed tissue. This is caused in part by the practical disadvantages inherent in the IF method, eg, separate tissue specimen and handling, UV microscopy, fading and impermanence of the label-making archiving, and difficult later investigation. Our aim for the present study is to evaluate IP as an alternative to IF in the diagnostic assessment of renal biopsy specimens.

METHODS

Proteolytic antigen retrieval, antibodies effective on deparaffinized sections, a sensitive detection system (Dako EnVision HRP; Dako, Copenhagen, Denmark), and a standardized and rigorously controlled procedure were applied to a series of renal biopsy specimens (n = 81) previously classified by means of light microscopy (LM) and IF. Staining for immunoglobulin G (IgG), IgA, IgM, C1q, and C3c were recorded as positive or negative for IF and IP in paired proportions, presuming that IF was the test standard.

RESULTS

Concordant observations were 71% for all (282 of 398 observations), 82% for IgG (65 of 79 observations), and 89% for IgA (72 of 81 observations). The majority of discordant observations (74 of 116 observations) were positive by means of IP, with mesangial deposits of IgM and C1q that were not found by IF. Statistically, there was no significant difference in outcomes between IF and IP for IgG, IgA, and C3c ( P > 0.2). In addition, IP staining allowed simultaneous evaluation of tissue by LM and therefore correlation between tissue structure and immune deposits not readily attained by IF.

CONCLUSION

In the present study, it is documented that for the detection of IgG, IgA, and C3c, IP applied to protease-digested deparaffinized sections of formaldehyde-fixed renal tissue is, with few exceptions, equal to IF on frozen sections. The EnVision HRP method used here is several times more effective in terms of primary antibody dilution than earlier existing IP methods, and because the avidin-biotin system is not involved, very little nonspecific background staining will occur. Discordant observations (116 of 398 observations; 29%) were in the majority (91 of 116 observations) due to positive IP findings of IgM and C1q, which deserve additional investigation.

Complement 4 levels as early predictors of poor response to surfactant therapy in respiratory distress syndrome

The aim was to determine whether stronger complement activation is an early predictor of poor response to surfactant treatment in infants with severe respiratory distress syndrome (RDS). Thirty-one preterm newborns with severe RDS (initial fraction of inspired oxygen [FiO (2)] > 0.5) and 22 healthy preterm newborns were studied. The study group was divided into two subgroups according to their response to natural surfactant 6 hours after administration: good responders had reduction in FiO (2) > 50% of the presurfactant level, and poor responders had a reduction in FiO (2) < or = 50%. Levels of complement 4 (C4) and C3c were measured in blood samples drawn at admission and 24 hours after birth. The poor responders to surfactant had significantly lower serum C4 levels at admission and in the first day of life than the good responders. The poor responders also had lower C3c levels at birth than the good responders, but higher C3c levels at 24 hours. Receiver-operator curve analysis revealed that, compared with C3c at admission, C4 at admission was a more sensitive and specific predictor of poor response to surfactant treatment in preterm newborns with severe RDS (area under the curve, 0.863; 95% confidence interval, 0.726 to 1; p = 0.001). Significantly decreased serum C4 at admission is a valuable early predictor of poor response prior to surfactant treatment in preterm newborns with severe RDS. C4 level may help investigators determine the mechanisms underlying poor responsiveness to surfactant.

Circulating immune complexes, immunoglobulin classes (IgG, IgA and IgM) and complement components (C3c, C4 and Factor B) in diabetic Nigerians

OBJECTIVE

To evaluate serum levels of circulating immune complexes (CICs), immunoglobulin classes (IgG, IgA and IgM) and Complement Components (C3c, C4 and Factor B) in Nigerians with Type 1 or Type 2 diabetes mellitus.

DESIGN

Case control study.

SETTING

University College Hospital, Ibadan, Oyo State, Nigeria.

SUBJECTS

Forty-two subjects with diabetic mellitus (17 Type 1 D. M. and 25 Type 2 D. M.) and 21 apparently healthy control subjects.

INTERVENTION

Serum level of CICs was measured by polyethylene glycol precipitation method while single radial immunodiffusion method was used to measure serum levels of immunoglobulins and complement components.

RESULTS

Only CICs were significantly higher in Type 1 diabetic subjects compared with the controls whereas CICs C3c, C4 and IgM were significantly increased in Type 2 diabetic subjects compared with the controls. The levels of CICs, C3c and IgM were significantly elevated in Type 2 diabetics compared with Type 1 diabetics.

CONCLUSION

CIC concentrations may serve as a useful index of depressed host defences usually associated with diabetics mellitus and that humoral immunity is deranged more in Type 2 diabetics compared with Type 1 diabetics. Probably as a result of hyperinsulinaemia associated with insulin resistance.

Innate immune system is implicated in recurrent aphthous ulcer pathogenesis

BACKGROUND

Recurrent aphthous ulcers (RAU) is a chronic inflammatory disease with evidence of inappropriate immune response. This study presents the status of innate immune system in RAU.

METHODS

Twenty RAU patients and 19 healthy individuals were selected. The status of peripheral blood neutrophils (reactive oxygen intermediates (ROI) production, CD11b, TNF-RI and TNF-RII expression), concentration of antioxidants, sTNF-R, C3c, C4 and haemolytic activity of the complement system, as well as mannose-binding lectin (MBL), in the serum of RAU patients in active stage and in remission of the disease were determined.

RESULTS

Peripheral blood neutrophils were primed in RAU, which resulted in increased ROI production by resting and fMLP-stimulated neutrophils and diminished ROI production after in vitro priming. The increased expression of CD11b on resting and fMLP-stimulated neutrophils in RAU may also point to their previous in vivo stimulation. The decreased total antioxidant status of serum observed in RAU may be a result of increased ROI production by peripheral blood neutrophils. The levels of C3c, C4 and haemolytic activity of the complement system were higher in RAU than in healthy people. No significant differences between active and remission RAU were noted.

CONCLUSION

Presented observations confirm that the innate immune system is involved in RAU pathogenesis.

Aggregation of human platelets in plasma by porcine blood cells in vitro is probably mediated by thrombin generation

The infusion of pig progenitor cells into baboons is associated with a thrombotic microangiopathy probably related to the interaction of these cells with the baboon endothelial cells and platelets. We have shown previously that pig peripheral blood mononuclear cells (p-PBMC), are able to activate the human coagulation cascade as they are able to generate thrombin when added to defibrinated plasma. In this work, we have tested the interaction of p-PBMC with human platelets to assess the capacity of p-PBMC to cause platelet aggregation and the possible role of complement activation in this aggregation. Human platelet aggregation assays, using collagen (1 or 2 microg/ml), were performed with platelets in platelet-rich plasma (PRP) or platelets washed by filtration. PRP or washed platelets were also incubated with p-PBMC or human PBMC (h-PBMC) at several concentrations and aggregation was measured. The effect of Dansylarginine N-(3-ethyl-1,5-pentanediyl)amide (DAPA), an inhibitor of thrombin, was studied on platelet aggregation caused by the pig cells. Complement activation was measured by deposition of fragment c derived from C3 splitting (C3c) on pig cells incubated with citrated platelet poor plasma (PPP). When human PRP was incubated with p-PBMC, aggregation was a consistent event quantitatively similar to that induced by collagen. No aggregation of washed platelets was observed when these were incubated with p-PBMC or h-PBMC. Aggregation of human platelets in PRP, induced by p-PBMC, was inhibited when DAPA (100 microm) was added to the incubation mixture (23%), indicating that the thrombin inhibitor blocked the capacity of p-PBMC to aggregate human platelets. No deposition of C3c fragments on p-PBMC was detected when the porcine cells were incubated for up to 20 min with citrated PPP. The fact is that p-PBMC induces human platelet aggregation in plasma being thrombin generation a likely explanation for this observation. Our data suggest that, in the system assayed, complement activation is not a cause of platelet aggregation. These findings are relevant for the clarification of the reported thrombotic microangiopathy complicating the intravenous infusion of pig cells in primates in attempts to induce pig tolerance in baboons.

Molecular characterization of the pig C3 gene and its association with complement activity

The complement system catalyzes direct lysis of micro-organisms and modulates phagocytosis, inflammation, humoral and cellular immune responses. Since the complement protein C3 is the central component within all pathways of complement activation, C3 is a candidate gene for complement activity and also for improved protection against many pathogens. The pig C3 gene was sequenced, screened for polymorphisms, and analyzed for association with hemolytic complement activity of the alternative and classical pathway (AH(50), CH(50)). C3c serum levels and haptoglobin (HP) serum concentrations were measured before and after vaccination against Mycoplasma hyopneumoniae, Aujeszky virus, and porcine reproductive and respiratory syndrome virus in F2 animals of a pig resource population based on crossbreeding of Duroc and Berlin Miniature Pig. The genomic C3 sequence covers 444 bp of promoter region, 41 exons and 40 introns, as well as 881 bp of the 3'-flanking region. The cDNA codes for a 1,661-amino acid precursor C3. Five polymorphic sites were detected in the 5'-UTR, intron 13, exon 15, exon 30, and the 3'-UTR. Within the resource population two haplotypes were found to segregate. Analysis of variance applying a repeated measures model revealed a significant effect of the interaction of C3 genotype and time of measurement relative to immunization on CH(50), AH(50,)and C3c that is likely to be due to variation of C3 expression. In contrast, the time course of the HP acute-phase reaction is not associated with C3 genomic variation. The association of C3 with complement activity indicates the importance of C3 as a candidate gene for natural resistance to micro-organisms, although the causative polymorphism modulating the expression of C3 remains to be delineated.

The increased histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by specific IgE

BACKGROUND

The release of histamine by iodinated contrast media (ICM) is higher in coronary artery disease patients than in noncoronary patients during coronary angiogram.

METHODS

Eighty-eight patients who underwent a coronary angiography were classified either as having coronary artery disease or as noncoronary patients. Histamine concentration was higher than the 6.8 nM upper limit in 7 cases (group 1), of whom six were coronary artery disease patients. We compared the IgE and complement fractions in plasma of these patients to two control groups with normal histamine blood level, one (group 2) with and the other (group 3) without coronary artery disease.

RESULTS

No difference of total IgE and C(3c) and C(4) complement fractions was found among the three groups. Anti-ioxaglate IgE-RIA was positive in only one patient from group 1. The affinity of drug-IgE binding in the serum of this patient was very low (Kd: 18.7 mM). The level of anti-ICM IgE detected by ioxitalamate- and iomeprol-Sepharose RIA was significantly higher in groups 2 and 3 than in group 1.

CONCLUSIONS

The higher histamine release in ischaemic heart disease patients undergoing coronaroangiography is not mediated by IgE or complement activation. Further studies are needed to investigate the implication of histamine release factors.

[Evaluation of C3c, C4 and C1-esterase inhibitor (C1-INH) during unstable angina]

BACKGROUND

The complement system plays an important role in the physiopathology of acute myocardial infarction (AMI) taking part in myocardial damage and reperfusion injury. The aim of this study is to investigate the plasmatic levels of some complement components (C3c, C4 and C1-INH) during unstable angina (C1-INH) and their different concentrations in relation to the different myocardial areas affected by ischemia.

METHODS

The plasmatic levels of C1-INH, C3c and c4 in 30 patients affected by unstable angina, and those of 22 clinically healthy subjects (control group) were evaluated (Nefelometer Behering). The patients were divided into four groups according to the different myocardial area affected by ischemia (anterior, antero-lateral, lateral or inferior ischemia),

RESULTS

No statistically significant differences were found in plasmatic levels of C3c, C4 and C1-INH between the group of patients and the control group. There is a statistically significant difference between the C1-INH levels of the patients with inferior ischemia and the plasmatic concentrations of the whole patients' group (p<0,01), the control group (p<0,01) and the group of patients with lateral ischemia (p<0,02).

CONCLUSIONS

There seems to be a different activation of the complement system during unstable angina, in relation to the different myocardial area affected by ischemia.

Serum complement C3c concentration in non-obese young insulin-resistant Mexicans

The aim of this study was to compare the serum complement C3 concentration between non-obese young insulin-sensitive and insulin-resistant Mexicans. A cross-sectional study was carried out in 28 healthy, non-obese [Body mass index (BMI) < 26 kg/m2] young (age 19-25 yr), male volunteers to measure the serum C3 concentration. In accordance with the constant for rate serum glucose disappearance (KITT) obtained from the insulin tolerance test, the subjects were divided into quartiles, considering as insulin-resistant individuals those in quartile 1, and insulin-sensitive subjects those in quartile 4. Serum C3c concentration was measured by a nephelometric method. Other biochemical characteristics were measured, like lipid profile and uric acid using enzymatic techniques. The serum C3 concentrations were similar (p = 0.949) between insulin-resistant and insulin-sensitive groups respectively (1.4 +/- 0.2 vs 1.3 +/- 0.1 g/l). There were no significant correlations between serum C3 concentrations and serum glucose, insulin levels, KITT and lipid profile. In conclusion, the serum complement C3c concentrations were similar between non-obese young insulin-sensitive and insulin-resistant Mexicans.

Complement activation plays a key role in the side-effects of rituximab treatment

Treatment with rituximab, a chimaeric anti-CD20 monoclonal antibody, can be associated with moderate to severe first-dose side-effects, notably in patients with high numbers of circulating tumour cells. The aim of this study was to elucidate the mechanism of these side-effects. At multiple early time points during the first infusion of rituximab, complement activation products (C3b/c and C4b/c) and cytokines [tumour necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and IL-8] were measured in five relapsed low-grade non-Hodgkin's lymphoma (NHL) patients. Infusion of rituximab induced rapid complement activation, preceding the release of TNF-alpha, IL-6 and IL-8. Although the study group was small, the level of complement activation appeared to be correlated both with the number of circulating B cells prior to the infusion (r = 0.85; P = 0.07) and with the severity of the side-effects. We conclude that complement plays a pivotal role in the pathogenesis of side-effects of rituximab treatment. As complement activation can not be prevented by corticosteroids, it might be relevant to study the possible role of complement inhibitors during the first administration of rituximab.

Detection of immune deposits in skin lesions of patients with Wegener's granulomatosis

BACKGROUND

Wegener's granulomatosis (WG) is considered a pauci-immune systemic vasculitis based on the absence of immune deposits in renal biopsies of patients with active disease. In animal models of antineutrophil cytoplasmic antibody (ANCA) associated glomerulonephritis, immune deposits along the glomerular capillary wall are present at early stages of lesion development. These deposits are degraded rapidly, resulting in "pauci-immune" lesions.

OBJECTIVE

To test the hypothesis that immune deposits can also be detected in early lesions of patients with WG, thereby initiating an inflammatory reaction that, in time, is augmented in the presence of ANCA, resulting in pauci-immune lesions later on.

METHODS

The presence of immune deposits in skin biopsies taken within 48 hours of lesion development was investigated. Direct immunofluorescence was used to examine 32 skin biopsies for the presence of immune deposits (IgG, IgA, IgM, C3c). When possible, a comparison was made between the immunofluorescence findings in renal and skin biopsies taken at the same time.

RESULTS

Four of 11 biopsies taken at initial presentation and four of 21 biopsies taken at the onset of a relapse of WG showed IgG and/or IgA containing immune deposits in the subepidermal blood vessels. All nine renal biopsies showed pauci-immune glomerulonephritis, irrespective of the presence (n=5) or absence (n=4) of immune deposits in the skin biopsy.

CONCLUSION

A substantial number of skin biopsies showed immune deposits during active disease. These results could support the hypothesis that immune complexes may trigger vasculitic lesions in WG.

Acute haemolysis in childhood falciparum malaria

Acute haemolysis associated with clinical episodes of high-level Plasmodium falciparum parasitaemia was studied in 20 children from an holoendemic area (coastal Tanzania). The change in blood haemoglobin (Hb) concentration ranged from -46 to g/L during the 72-h observation period and was linearly related to maximum parasitaemia. Balance studies between loss of blood Hb, increase in plasma Hb and appearance of Hb in the urine indicated that extravascular clearance of red cells was the predominant mode of erythrocyte clearance. Most subjects, however, showed minor signs of intravascular haemolysis. The plasma Hb was << 1% of blood Hb and haemoglobinuria was detected in 14/20 children but the excretion of Hb in urine was < 0.5% of total Hb loss. Haemoglobinuria was, however, a marker of severe haemolysis, since the maximum blood Hb loss in children without haemoglobinuria was 10 g/L. Erythrocyte-bound opsonins known to induce erythrophagocytosis, i.e., complement C3c fragments and autologous IgG, were increased in all patients. In the patients with major haemolysis, the changes correlated to the haemolysis over time. Hence, a similar mechanism for predominantly extravascular erythrocyte clearance may be operative in acute malarial anaemia, normal erythrocyte senescence and other forms of acute haemolysis.

Contrast in the efficacy of hDAF mouse hearts between ex vivo perfusion and transplantation into primates

In recent experiments, in which we compared hDAF transgenic rat hearts perfused with 15% human serum in the Langendorff device and hDAF rat hearts transplanted into cynomolgus monkeys, we demonstrated that in the ex vivo heart perfusion model both homozygous and heterozygous hDAF hearts survived longer as nontransgenic controls. Surprisingly, we found that only homozygous hDAF hearts were protected against hyperacute rejection in vivo. The first aim of this study was to determine whether perfusion of mouse hearts with higher human serum concentrations or human blood might explain some of the differences found in survival time of the recently performed experiments with rat heart xenografts. Secondly, we investigated whether the observed differences in survival times of rat xenografts between in vivo and ex vivo transplantation would also hold for mouse hearts transgenic for hDAF. An ex vivo model was used to perfuse hDAF mouse hearts and controls with human serum or blood, and hDAF transgenic hearts and controls were transplanted into cynomolgus monkeys. hDAF transgenic mouse hearts survived significantly longer than their controls when perfused with 15% human serum, but no difference was found when 30% human serum was used, or when these hearts were transplanted into cynomolgus monkeys. However, in both the in vivo and ex vivo models the amount of PMNs adhering to the vascular endothelium was significantly lower in hDAF transgenes as compared with their controls. In conclusion, in the ex vivo situation, the efficacy of hDAF transgenesis in preventing HAR is limited by serum complement concentration.

Renal involvement induced by human parvovirus B19 infection

In an attempt to clarify the renal involvement induced by human parvovirus B19 (HPB19) infection, we investigated 6 adult patients with transient urinary abnormalities followed by erythema infectiosum. All patients had HPB19-specific IgM antibody and showed mild proteinuria of 0.2-1.2 g/day with or without microscopic hematuria. In 5 patients a decrease of complement was present, and in 2 the circulating immune complex levels were elevated. All patients showed mild or moderate endocapillary proliferation with leukocytic infiltrates in glomeruli and leukocytic infiltrates with edema around interlobular arteries and arterioles. Immunofluorescence microscopy revealed C3c deposits with immunoglobulins along the glomerular capillary walls and in the walls of small arteries and arterioles. Electron microscopic studies showed swelling of the endothelial cells and small electron-dense deposits in mesangium (in all 6 patients) and subendothelium (in 5 of 6 patients). However, HPB19 VP1 and VP2 capsid antigens were not demonstrated in the glomerulus or the vascular wall in any patient. These findings suggest that the renal lesions caused by an immune complex mediated phenomenon would be closely correlated with the HPB19 infection, although the precise mechanism is not entirely clear, and that in adults HPB19 should be thought of as a possible cause of acute postinfectious glomerulonephritis.

The biocompatibility of silicone, fluorosilicone and perfluorocarbon liquids as vitreous tamponades. an ultrastructural and immunohistochemical study

PURPOSE

To investigate the interactions occurring at the interface between some currently used vitreous tamponading substances and the ocular tissues, in an early follow-up after surgery.

METHODS

Adult albino rabbit eyes underwent vitrectomy and were injected intravitreally with silicone oils at 1,000 or 3,000 cSt, fluorosilicone oil and perfluorodecalin. Different morphological techniques (light microscopy, scanning and electron microscopy, immunohistochemistry) were applied.

RESULTS

All the tested materials, although non-toxic, penetrate the ocular tissues also at the anterior segment level, and in the long-term follow-up this can yield functional impairment. No massive inflammation has been detected in the zones in contact with the materials, but immunoglobulins and complement fractions are anyway present in the stroma of various tissues and around the droplets of emulsified materials, suggesting a local immune reaction.

CONCLUSIONS

Data from this study confirmed that a permanent vitreous substitute, showing a perfect biocompatibility, still does not exist. The indication to remove the tamponading substance within 2 months after the surgery emerges from this investigation, confirming previous studies. Despite some negative features, silicone oil still appears the most biocompatible material for vitreous replacement.

Immunological and clinical follow up of hepatitis C virus associated cryoglobulinaemic vasculitis

OBJECTIVE

To study immunological markers and compare these markers with standard measures for the clinical and immunological follow up of vasculitis activity in hepatitis C virus (HCV) associated cryoglobulinaemic vasculitis (CV).

METHODS

Serial serum samples from eight patients with newly diagnosed HCV associated CV were followed during interferon alpha treatment induced remission of the CV. Vasculitis activity and disease extent were evaluated with the Birmingham vasculitis activity score (BVAS) and disease extent index (DEI). Cryoglobulinaemia, complement levels (C3c, C4, and CH50), rheumatoid factor (RF), autoantibodies such as antinuclear antibodies, soluble interleukin 2 receptor (sIL2r), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble CD30 (sCD30) were determined.

RESULTS

All patients achieved either complete or partial remission of their CV during interferon alpha treatment. There was a significant reduction in vasculitis activity and disease extent (BVAS, DEI), cryoglobulinaemia, RF, sIL2r, sICAM-1, and sCD30. Complement C3c levels increased significantly during this period. Erythrocyte sedimentation rate and levels of complement C4 and CH50 did not change significantly. Both clinical measures (BVAS and DEI) correlated significantly only with C3c and sCD30.

CONCLUSIONS

Although this study was of only a small group of patients, it shows that BVAS and DEI as clinical measures and C3c and sCD30 as immunological markers may be useful in the follow up of disease activity of HCV associated CV. The data indicate that activity of the humoral (cryoglobulinaemia, RF, autoantibodies) and cellular (sIL2r, sICAM-1, sCD30) immune response and endothelial damage (sICAM-1) are found in HCV associated CV.

Regulation of in situ complement activation via the lectin pathway in patients with IgA nephropathy

The lectin pathway, which is initiated by mannose-binding lectin (MBL) and MBL-associated serine protease (MASP), is one of the possible routes to activate the complement cascade in immunoglobulin A (IgA) nephropathy. The purpose of this study was to elucidate the regulatory mechanism of the pathway. Levels of complement activation products and regulatory proteins were measured in sera from 27 patients with IgA nephropathy, and generation of fluid-phase complement activation products in the presence of pooled normal human serum was quantified to evaluate activation in vitro. Although there were no significant differences in the serum levels and in vitro activation between the MBL-MASP positive (n = 14) and negative (n = 13) groups, there were positive correlations between complement activation products (Bb fragment and C4d fragment) and regulatory proteins (factor H, C4-binding protein, and C1 inhibitor) in the MBL-MASP-positive group. Furthermore, immunohistochemical studies demonstrated glomerular deposition of the regulatory protein (C4-binding protein, alpha2-macroglobulin, and factor H) in all patients in the MBL-MASP-positive group. These findings suggest that the regulatory proteins control in situ complement activation via the lectin pathway immediately, and continuous activation due to inadequate control will lead to the advanced glomerular injury.

Complement activation in SCID and nude mice is related to severity of tissue inflammation in the Candida mastitis model

A small animal model of localised candidiasis is needed for the evaluation of new antifungal compounds. Mammary glands of immunocompetent (BALB/cJ) and immunodeficient (SCID and athymic nude) mice were infected with a wild-type of Candida albicans. Some of the animals were treated with amphotericin B (AmB) while others were treated with saline and acted as controls. The histologic changes of infected mammary gland tissues and a number of other organs were evaluated. Complement (C) activation was analysed by immunoelectrophoretic quantification of molecules with C3c epitopes (C3, C3b, iC3b, and C3c) in serum. In all animals the organisms were confined to the mammary glands. Serum C3c levels were significantly higher (P<0.05) in infected untreated BALB/cJ and SCID mice, which also had severe mammary gland tissue inflammation, compared with control mice treated with AmB (4 mg kg(-1) i.p. once daily for 4 days). Both treated and control nude mice showed less tissue inflammation compared to BALB/cJ and SCID mice, and revealed insignificant activation of the complement system. It is concluded that innate immune response is important in the control of candidiasis and that the murine mastitis model is useful for immunopathological studies as well as evaluation of potential antifungal compounds.

Complement activation during blood sampling procedures alters the expression of CD11b/CD18 on human neutrophils

BACKGROUND AND OBJECTIVES

Differences in blood sampling and separation techniques can affect the quantitative levels of activation markers on different leukocyte subsets. We examined the effect of two sampling procedures of EDTA blood on the quantitative levels of two markers, the CD11b/CD18 antigen and the EG2 epitope on intracellular eosinophilic cationic protein (ECP), in neutrophils and eosinophils, respectively.

MATERIALS AND METHODS

Sample I was collected directly after completion of blood donation by an open technique and constant flow from the transfer tube directly into EDTA tubes. After sampling, the transfer tube was manually closed with a clamp. Sample II was collected 45 s later by the same technique by opening the clamp.

RESULTS

We found a significantly (p < 0.01) higher expression of CD11b/CD18 on neutrophils collected by sampling procedure II than on those collected by sampling procedure I. In contrast, we did not find any difference in the intracellular ECP expression between sampling procedures I and II. To further explore the mechanisms for the observed upregulation of CD11b/CD18, fragments of a transfer tube were incubated with normal human serum (NHS) and heat-inactivated NHS (NHS56), respectively, for 60 min at +37 degrees C. Leukocytes from healthy blood donors were then incubated for 15 min at +37 degrees C with these serum preparations. The CD11b/CD18 expression was significantly higher (p < 0.01) on neutrophils incubated with transfer-tube-activated NHS compared with NHS alone. However, when leukocytes were incubated with transfer tube activated NHS56, no difference was observed compared with incubation with NHS alone. In addition, by using confocal laser scanning microscopy, we could identify complement (C3c) deposits on the inner surface of the transfer tube fragments incubated in NHS, but not in NHS56,

CONCLUSIONS

The quantitative level of the activation marker CD11b/CD18 on neutrophils, but not the EG2 epitope on intracellular ECP in eosinophils is significantly increased by a slight modification of the blood sampling procedure. It is suggested that the observed upregulation of CD11b/CD18 is caused by complement activation within the transfer tube. The results emphasize the importance of in-house data on the effect of variations in sampling procedures, particularly when data from healthy blood donors are included in clinical studies.

Effects of new polymer-coated extracorporeal circuits on biocompatibility during cardiopulmonary bypass

An inflammatory response due to bioincompatibility of extracorporeal circuits is a major clinical issue during cardiopulmonary bypass (CPB). By using a swine model, we determined whether new polymer-coated circuits, the blood-contacting surfaces of which are coated with poly(2-methoxyethylacrylate) (PMEA), would reduce the inflammatory response during CPB. Plasma bradykinin levels and the percentages of CD35-positive monocytes in PMEA-coated circuits were significantly lower than those in uncoated circuits during CPB. The amount of proteins adsorbed on the PMEA-coated circuits was significantly lower than that on the uncoated circuits (0.30 microg/cm2 versus 3.42 microg/ cm2). Almost no IgG, IgM, or C3c/d was detected in proteins adsorbed on the PMEA-coated circuits although these proteins were clearly detected in proteins adsorbed on the uncoated circuits. We concluded that PMEA coating could reduce complement activation during CPB by suppressing the adsorption of IgG and IgM, which activate C3 via the classical pathway, on the surface of the circuits.

Birmingham vasculitis activity score, disease extent index and complement factor C3c reflect disease activity best in hepatitis C virus-associated cryoglobulinemic vasculitis

OBJECTIVE

Clinical measures of vasculitis activity (Birmingham vasculitis activity score = BVAS) and disease extent (Disease Extent Index = DEI), serological and immunological parameters were evaluated for the monitoring of hepatitis C virus (HCV)-associated cryoglobulinemic vasculitis (CV), treated with either cyclophosphamide or interferon-alpha 2b depending on disease severity.

METHODS

Serial serum samples of 15 patients with HCV-associated CV were analyzed, and BVAS, DEI, serological and immunological parameters were recorded at diagnosis and during therapy. Eight patients were treated with interferon-alpha 2b and 7 patients with cyclophosphamide.

RESULTS

A complete or partial response of the CV was seen in both treatment groups. BVAS, complement factor C3c, cryoglobulinemia, and rheumatoid factor significantly decreased in both treatment groups during 6 months (p < 0.05). DEI decrease was significant in the cyclophosphamide group (p < 0.05), and there was a trend in the interferon-alpha 2b group (p = 0.06). BVAS and DEI were significantly positively correlated, and both parameters were significantly negatively correlated with C3c levels in both treatment groups (interferon-alpha 2b/cyclophosphamide: r = -0.89, p = 0.001 versus r = -0.87, p < 0.001, respectively) whereas other parameters were not, e.g. ESR and CRP.

CONCLUSIONS

Patients with different degrees of disease severity, treated with either cyclophosphamide or interferon-alpha 2b depending on their disease activity, achieved remission of their CV. BVAS, DEI and C3c were especially useful in the follow-up of HCV-associated CV. C3c correlated with BVAS and DEI during therapy and provided additional information about vasculitis activity that was not reflected by other serological or immunological parameters, e.g. ESR or CRP.

Low serum C3, leukopenia, and thrombocytopenia: unusual features of henoch-schonlein purpura

Henoch-Schonlein purpura (HSP) affects predominantly the skin, joints, gastrointestinal tract and kidney. Although the pathogenesis is probably of immune origin and complement activation is thought to play a role, laboratory findings including the serum level of the complement components are usually normal. We present a patient with a severe form of HSP nephritis who had unusual laboratory findings of a low level of C3, mild leukopenia and thrombocytopenia. These findings may further support the importance of complement activation in the pathogenesis of HSP.

Complement haemolytic activity (classical and alternative pathways), C3, C4 and factor B titres in healthy children

Values of complement lytic activity of classical and alternative pathways, assessed by measuring the time required to lyse 50% of target red blood cells, and the concentration of complement components C3, C4 and factor B were estimated in the sera of 103 healthy children aged 3 to 14 y. Age-dependent variations were seen in the C3 and factor B concentrations, but not in C4, with the highest values found among 5-6-y-old children. Variations in classical and alternative lytic activity were not detected in this group of children, although the values are significantly different from our previously published data on adults, using the same kinetic assay (1). We also evaluated the relationship between the lytic activity of the classical (CPT) and alternative pathways (APT) and the levels of complement components. There were significant correlations between: APT and factor B, APT and C3, C3 and C4, C3 and factor B, and C4 and factor B concentrations. The normal ranges measured here can be used in the initial screening of Brazilian children presenting diseases involving the complement system. This study also contributes to a better understanding of the complement system ontogeny.

Immunity to spermatozoa and male fertility

Immunological characterization of semen and male fertility are discussed. The pH of seminal plasma is very similar in groups of fertile and infertile men. Nonspecific immunological factors such as lysozyme, C3c, alpha-1 antitrypsin and beta-2 microglobulin were significantly higher in 14% of infertile men. Seminal antibodies agglutinating spermatozoa are frequently observed in IgG and IgA isotypes. High levels of seminal anti-phospholipid antibodies in seminal plasma could influence epitopes on the endometrium, oocyte or early embryo in patients with repeated unexplained spontaneous miscarriages.

Detection of humoral rejection in human cardiac allografts by assessing the capillary deposition of complement fragment C4d in endomyocardial biopsies

BACKGROUND

There are no well-established diagnostic criteria to detect humoral rejection in organ transplantation. The value of commonly used markers in immunohistochemistry, such as C1q, C3c, IgG, IgM and fibrinogen, is questioned by some groups. Complement fragment C4d is a more stable marker of complement activation as it is covalently bound to graft capillaries. C4d has been shown to identify clinically relevant, but otherwise undetectable humoral anti-graft reactions in human kidney transplants.

METHODS

Immunohistochemical techniques were used to evaluate 155 endomyocardial biopsies from 56 heart transplant recipients less than 3 months post transplantation for the presence of capillary C4d staining. In a subset of patients, C4d staining was compared with C1q, C3c, IgM and fibrin staining and was correlated with clinical outcome.

RESULTS

Within 3 months 9 of 56 patients died. Five of these nonsurvivors had prominent C4d staining (p < .05), whereas C1q, C3c and IgM showed no correlation with clinical outcome. Presence of fibrin correlated with clinical outcome and C4d staining (p < .05).

CONCLUSIONS

The capillary deposition of complement split product C4d in human endomyocardial biopsies was significantly associated with graft loss. Determination of fibrin deposition may yield additional information to establish a diagnosis of humoral rejection. The immunohistochemical assessment of capillary deposition of C4d and fibrin appears to be an appropriate tool for the identification of patients, who may require additional or alternative immunosuppressive therapy targeted against the humoral immune system.

Spatial arrangement of subepithelial deposits in lupus and nonlupus membranous nephropathy

Subepithelial deposits are a common feature of idiopathic membranous glomerulonephritis (MGN) and lupus membranous glomerulopathy (LMGN). We investigated the spatial arrangement of immunoglobulin G (IgG) and C3c fraction of complement (C3c) in the immune deposits of MGN and LMGN with confocal laser scanning microscopy to correlate specific patterns of IgG-C3 interactions with different diseases. Ten patients with MGN and 8 patients with LMGN (World Health Organization class VB) were selected. A determination of the spatial arrangement of the two fluorochromes and the glomerular area occupied by each fluorochrome was performed for each case. Our results showed MGN specimens have an orderly distribution of IgG and C3c, with each deposit showing an outer ring of sole IgG. IgG was always more abundant than C3c (1,619 +/- 271 v 790 +/- 105 micrometer(2), P = 0.002). In LMGN, IgG and C3c were haphazardly arranged, with deposits made of C3c only and an outer ring of IgG only rarely present. Also, the relative amounts of the two antigens were variable, and two groups could be identified (group 1: IgG, 5,515 +/- 1,179 micrometer(2) v C3c, 4,810 +/- 1,174 micrometer(2); P = 0.02; group 2: IgG, 3,358 +/- 658 micrometer(2) v C3c, 4,047 +/- 740 micrometer(2); P = 0.03). Our data show that diffuse IgG capping of the subepithelial immune deposits is diagnostic of MGN. The absence of an orderly three-dimensional arrangement in LMGN deposits (ie, outer ring of IgG) is likely to render active complement components more readily available to inflammatory activities.

Serum complement levels in children in communities with different levels of air pollution in Japan

To investigate the effects of air pollution on human health, we determined serum concentrations of complement components C3c and C4 in 1037 children who lived in 4 communities with different levels of air pollution in Japan. Serum levels of C3c and C4 were higher in children who lived in Osaka, which had a high level of air pollution, than in children who lived in areas of low air pollution. In boys, both C3c and C4 levels were increased significantly as concentrations of air pollution increased in the communities. In girls, however, the relationship was not significant. Serum levels of C3c and C4 did not differ with respect to asthma or wheezing. These findings suggest that serum C3c and C4 levels in children reflect the effects of exposure to air pollutants in urban districts. Boys appeared to be more susceptible to the effects of air pollution than girls.

A new immunoelectron microscopy approach for the detection of immunoglobulin and complement deposits in epoxy-embedded renal biopsies

The purpose of this study was to examine the diagnostic value of a new immunoelectron microscopy technique (IEM) for detection of immunoglobulin and complement deposits in epoxy-embedded renal biopsies. Twenty-four renal biopsies were embedded in epoxy resin following a tissue processing involving moderately increased amount of accelerator, DMP-30 (Tri(Dimethyl Amino Methyl) Phenol), in the infiltration steps. Following antigen retrieval by heating in citrate buffer, immunogold labeling was performed on ultrathin sections from these epoxy blocks with antibodies against immunoglobulins and complement. The sections were counterstained with urnayl acetate and lead citrate without any enhancing procedures. The preservation of the ultrastructure with this method was similar to that usually seen in epoxy embedded material. The immunogold labeling was intense and distinct. Immunofluorescence (IF) for light microscopy was carried out on frozen sections of parallel tissue samples. The correspondence between IF and IEM were good, but in some cases higher sensitivity for IgA with IEM than IF was observed in the sense that smaller amounts of antigen were detectable with IEM. The combination of moderately increased amount of accelerator and antigen retrieval is superior to previous methods with respect to ease of use, ultrastructural preservation, and intensity of the immunolabeling. Moreover, the renal tissue can be processed in an automatic ultraprocessor together with other specimens which are to be prepared for routine electron microscopy.

High-dose intravenous immunoglobulin treatment activates complement in vivo

Several complement modulating effects of high-dose intravenous immunoglobulins (IVIG) have been proposed from in vitro studies and experimental animal models. However, the in vivo effects of IVIG on plasma complement in humans are yet not known. We have investigated the in vivo effects of IVIG on complement in seven women with unexplained recurrent spontaneous abortion who were without evidence of autoimmune disease. Samples were obtained before and after the very first infusion of IVIG. There was a marked increase in immunoglobulin G (IgG) from (median and range) 12.4 (9.4-15.9) to 26.8 (22.4-30.0) g/l but no change in immunoglobulin A (IgA) or immunoglobulin M (IgM). A significantly increased complement activation was demonstrated using neoepitope-specific enzyme immunoassays to the activation products C3bc (median increased from 9.8 to 31.2 AU/ml), Bb (0.66-1.66 g/ml), C5a (10.5-12.7 ng/ml), and TCC (0.81-2.19 AU/ml) (P = 0.015 for all). There were no changes in antigenic concentrations of individual complement components or regulators (C1q, C4, C3, C1-inhibitor, C4b-binding protein) and no decrease in complement haemolytic activity (classical and alternative CH50), which were all within the normal range. The classical pathway activation products C1rs/C1-inhibitor complexes, C4bc and C4d were elevated in all patients before IVIG treatment and did not change significantly during treatment. In conclusion, IVIG induced a significant activation of complement in vivo.

Differences in glomerular leukocyte infiltration between IgA nephropathy and membranoproliferative glomerulonephritis

BACKGROUND

An important aspect in glomerular nephritic processes is the enhanced influx of leukocytes into the glomerulus.

METHODS

To investigate the mechanisms of intraglomerular leukocyte infiltration in IgA nephropathy (IgA-N) and membranoproliferative glomerulonephritis type I (MPGN-I), we immunohistochemically examined the intraglomerular expression of leukocyte function-associated antigen-1 (LFA-1, CD11a/CD18), macrophage-1 (Mac-1, CD11b/CD18) and intercellular adhesion molecule-1 (ICAM-1, CD54) together with glomerular deposition of C3c and fibrinogen.

RESULTS

In IgA-N (n=42), LFA-1+ cells were distributed mainly in glomeruli with intense expression of ICAM-1, and there was a positive correlation (P<0.001) between the number of LFA-1+ cells and the degree of ICAM-1 expression. Mac-1+ cells had no correlation with glomerular C3c deposition, but had a significant correlation with fibrinogen deposition (P<0.05). The number of LFA-1+ cells was significantly greater than of Mac-1+ cells (P<0.05). The number of LFA-1+ cells was strongly correlated with that of CD68+ cells (P<0.00001). In MPGN-I (n= 43), on the contrary, Mac-1+ cells correlated only with C3c deposition (P<0.001), and they were observed mainly in peripheral loops of glomerular capillaries where C3c was deposited with a similar distribution. However, there was no relationship between LFA-1+ cells and ICAM-1 expression. The number of Mac-1+ cells was greater than that of LFA-1+ cells (P<0.0001), and most Mac-1+ cells were identical to CD15+ cells.

CONCLUSION

These results indicate the possibility that different mechanisms may cause glomerular leukocyte infiltration in various forms of human glomerulonephritis. The LFA-1/ICAM-1 pathway may play an important role in glomerular leukocyte infiltration in IgA-N, while the Mac-1/complement pathway may be important in MPGN-I. The former may promote mainly the infiltration of CD68+ cells, and the latter may promote that of CD15+ cells. In addition, Mac-1+ cells may act as fibrinogen and complement receptors in IgA-N and MPGN-I, respectively.

Immunoglobulin and C3-activator profile of the microbiology laboratory worker

The levels of immunoglobulin, C3-Activator and C3c in the sera of members of staff who have been continuously engaged for upwards of 10 years in the microbiological routine laboratory of a teachings hospital were determined. These were compared with the local normals, with those of the junior members of staff in the same laboratory but who had put in less than 5 years continuous service and with a control group. The means in all five determinations were much higher in the senior members of staff than the normal standards of the area, particularly the IgG, which was almost double the local normals. The levels for the junior staff were on the whole slightly higher than the control group. The increase in the levels of immunoglobulins with corresponding increases in C3-Activator and 3Cc suggest that immunological reactions, with the binding of complement in the alternate and classical pathways of activation are taking place in most of these senior workers. In the absence of any manifest illness in the senior staff, the findings may suggest a high degree of immunological protection.

Serum protein leakage in Alzheimer's disease revisited

Leakage of serum proteins into the brain parenchyma has been repeatedly used as evidence of blood-brain barrier (BBB) damage in experimental and human studies. However, there is no consensus in the literature concerning this phenomenon in Alzheimer's disease (AD). We have examined this question by comparing frontal lobe sections in seven groups of patients: Multi-infarct dementia (n = 6), AD with (n = 10) and without (n = 10) infarcts, age-matched controls with (n = 10) and without (n = 10) infarcts, controls with neurodegenerative diseases other than AD, and young controls (n = 10). An additional series compared prospectively followed patients with a diagnosis of either multi-infarct dementia (n = 5) or AD (n = 4). Albumin was detected in white-matter astrocytes in all cases, without significant variation in intensity. In addition, diverse combinations of neurons, astrocytes, and (in AD patients) senile plaques were present in the cerebral cortex in an inconsistent manner. Semiquantitative analysis showed no statistically significant differences among groups. Anti-IgG labeled astrocytes in infarcts only. Complement C3c component was detected in rare amyloid plaques in a minority (15%) of AD cases. Selective labeling of AD-specific lesions in a patchy manner was observed for serum amyloid P. We conclude that there is no immunohistochemical evidence of alteration of the BBB in Alzheimer's disease with or without vascular factors or in old age. Serum amyloid P binds avidly to AD lesions, but our findings are consistent with leakage through the BBB during the agonal or immediate postmortem period. Finally, no specific pattern of abnormality in the BBB was detected in multi-infarct dementia.

Immunopathogenesis of canine aural haematoma

Data are presented from 15 dogs with aural haematoma. The series included six Labrador retrievers and four golden retrievers and the mean age was 8.0 +/- 3.02 years. Five dogs had evidence of pruritic skin disease and five further cases had other concurrent disease. Haematology and serum biochemistry were normal in 12 and 13 of the 15 dogs, respectively. All dogs were Coombs' negative and serum antinuclear antibody had negative or low titres in all the 11 cases tested. Histopathological examination of biopsies from the affected ears revealed variable degrees of erosion of auricular cartilage with fibrovascular granulation tissue filling the cartilage defects. There was minimal perichondral inflammation. The biopsies were studied by immunohistochemistry for deposition of immunoglobulin G (IgG), immunoglobulin M (IgM) and complement C3. In one dog there was basement membrane zone deposition of IgG and in another there was focal interepithelial deposition of both IgG and IgM. The findings of this study do not support an autoimmune pathogenesis for canine aural haematoma, but suggest that an early immunological event may underlie the observed cartilage erosion.

Immunoelectron microscopy on epoxy sections without deplasticizing to detect glomerular immunoglobulin and complement deposits in renal diseases

Twenty renal biopsies were studied by immunoelectron microscopy (IEM) after embedding in epoxy resin. Immunogold labeling for immunoglobulins and complement C3 was performed on the epoxy sections, which were not subjected to any kind of etching or deplasticizing prior to the immunolabeling. The concentration of accelerator, DMP-30 (Tri (Dimethyl Amino Methyl) Phenol), was increased in the infiltration and embedding steps far beyond the values normally used to make immunolabeling of these antigens possible on epoxy sections. The sections were stained with tannic acid accompanied by uranyl acetate and lead citrate. Immunofluorescence (IF) for light microscopy was carried out on frozen sections of parallel tissue samples. Some cases with IgA-nephritis demonstrated a higher sensitivity for IEM than IF, in the sense that smaller amounts of antigen were detectable with IEM. Ultrastructural preservation with this method was approximately the same as that usually seen on epoxy-embedded material. By combining excellent immunolabeling with nearly optimal ultrastructural morphology in one procedure, this method is useful particularly in situations where the material available is limited, such as in studies of renal biopsies. As far as we know, this is the first time that immunoglobulins have been satisfactorily immunolabeled on epoxy sections without etching or deplasticizing.

Mechanism of infiltration and activation of glomerular monocytes/macrophages in IgA nephropathy

Glomerular deposits of fibrin-related antigens (FRA), C3c, membrane attack complex (MAC) were examined by the immunoperoxidase method on 176 renal biopsy specimens from 120 cases with IgA nephropathy including 56 cases with sequential biopsies. On 47 sets of repeated renal biopsy specimens, the glomerular infiltration of the following immune cells was examined by the indirect immunoperoxidase method; immune cells positive for C3bi receptor (C3biR; CR3/CD11b, CR4/CD11c), HLADR antigen and several leukocyte surface markers (CD45R, CD3, CD15 and CD68). Twenty-four-hour urine protein (UP) at the renal biopsy was also evaluated. The glomerular deposition of FRA was inversely correlated with C3c/MAC deposition (p < 0.00001). Most cases (163 of 176) were classified into the following two types; type C with dominant deposition of C3c (97 cases) and type F with dominant deposition of FRA (66 cases), except for 13 cases with equivalent deposits of C3c and FRA (7 cases, type B) and without C3 or FRA deposits (6 cases, type O). In 56 rebiopsied cases, apparent conversion from type F or C into the other was observed only in one case though a few cases in type C lost or reduced C3c deposition to an equivocal type at the follow-up biopsy, which were included in type C', an expanded category of type C. In the whole cases, the glomerular infiltration of immune cells was significantly correlated with FRA deposition (p < 0.0002) but not with C3c. Glomerular CD11c+ cells were significantly correlated with C3c deposition in type C' (p < 0.0001), but not in type F. Glomerular HLADR positive immune cells were significantly correlated with glomerular CD3+ T cells in type F (p < 0.001), but not in type C'. In type C', UP was significantly correlated with glomerular CD11c+ cells (p < 0.0001) but not with CD 15+ or HLADR+ cells. On the other hand, in type F, UP was significantly correlated with CD 15+ and HLADR+ cells (p < 0.001) but not with CD11c+ cells. These results suggested that there are multiple pathways in inducing glomerular infiltration of immune cells in IgA nephropathy. In type C, local activation of complements might primarily induce immune cell infiltration through C3biR and these C3biR+ cells are involved in inducing proteinuria. On the other hand, in type F, in which complement activation is weak, immune cells might infiltrate directly through their Fc receptor or MHC class II antigens, and might be activated by T-cell/macrophage interaction to induce proteinuria.

Complement in acute and chronic arthritides: assessment of C3c, C9, and protectin (CD59) in synovial membrane

OBJECTIVES

To investigate the role of complement cascade induced damage and protection against it in acute arthritides compared to rheumatoid arthritis and other chronic joint derangements.

METHODS

C3c, C9, and protectin (CD59) were examined by avidin-biotin-peroxidase complex staining.

RESULTS

Marked deposits of C3c and C9 were found in synovial vasculature and intercellular matrix of the lining in rheumatoid arthritis and in acute arthritides (including bacterial, reactive, and osteoarthritis flare up). Furthermore, protectin was not visible in synovial lining cells and was relatively weakly expressed in stromal and endothelial cells in rheumatoid arthritis; also in acute arthritides protectin expression was weak. In contrast, C3c and C9 deposits were not found in chronic conditions associated with degenerative diseases (osteoarthritis and osteochondritis dissecans) or mechanical causes (patellar luxation and a ruptured meniscus), in which also the protectin expression was prominent in synovial lining, endothelial and some stromal cells.

CONCLUSIONS

Activation of the complement in rheumatoid arthritis and in acute arthritides seems to be associated with a decreased protection of synovial cells against cellular effects and lysis mediated by membrane attack complex.

Immunological alterations in sera of persons living in areas with different air pollution

The present study aimed to investigate immune parameters in sera of adult persons chronically exposed to different degrees of ambient air pollution. As related to air pollution derived from coal mining industry and coke plants, a significantly increased prevalence of cases with abnormally high serum levels of the immunoglobulins IgA and IgM as well as the complement component C3c was found as compared with a less polluted control area, indicating a higher stimulation of acute reactants in combination with a polyclonal immune response. These findings may be attributed to elevated concentrations of airborne particulates, suggesting that permanent exposure to increased levels of airborne particulates leads to chronic irritation of the airways in association with activation of the immune system, which may give rise to an enhanced risk for chronic airway diseases.

Effects of environmental tobacco smoke on serum levels of acute phase proteins in schoolchildren

BACKGROUND

Few biological changes due to long-term exposure to environmental tobacco smoke (ETS) have been identified. This study examined the relationship between exposure to ETS and serum levels of acute phase proteins among children.

METHODS

The concentrations of the third component of complement (C3c), haptoglobin (Hp), alpha 1 acid glycoprotein (alpha 1AG), and ceruloplasmin (Cp) were determined in serum samples obtained from 480 school-children. Exposure to ETS was assessed from responses to questionnaires.

RESULTS

Serum levels of C3c, Hp, and alpha 1AG were significantly higher among boys living in households in which there were smokers other than their parents than among boys with no smokers in their family or those in households were only the father smoked. Levels of C3c, Hp, and alpha 1AG in relation to the level of ETS exposure were significantly increased among boys exposed to ETS of 11 or more cigarettes per day. Among girls, increased alpha 1AG levels were associated with exposure to high levels of ETS, but no differences were found in any of the other proteins. Cp levels were not affected by exposure to ETS among either boys or girls.

CONCLUSIONS

These findings suggest that the serum levels of C3c, Hp, and alpha 1AG among schoolchildren may reflect different levels of exposure to ETS. Boys seemed to be more susceptible to ETS exposure than girls.

Leucocytoclastic vasculitis induced by prolonged exercise

Many people develop skin symptoms after long-distance walks, but little is known about the aetiology of these. In this study we took 11 biopsies from 10 long-distance walkers who walked 80 km. All biopsies originated from purpuric lesions on the lower legs, which had appeared during walking. In all 11 specimens, signs of a leucocytoclastic vasculitis were present with leucocytoclasis, exocytosis of erythrocytes and a granulocyte/mononuclear perivascular infiltrate. Immunofluorescence investigations showed deposition of C3c in many specimens and immunoglobulin M in some. The occurrence of a leucocytoclastic vasculitis after prolonged exercise may be explained by the existence of an exercise altered cutaneous microcirculation, complement activation and an altered immune function.

Clinical significance of complements in ascitic diseases: elevated complement levels disapproving the liver disease origin

In a two-year period, ascitic fluid concentrations of complement 3c and complement 4 were measured in 110 patients with sterile cirrhotic ascites, 31 patients with spontaneous bacterial peritonitis, 65 patients with hepatocellular carcinoma, 36 patients with peritoneal carcinomatosis and 12 patients with miscellaneous diseases (nephrotic syndrome 4, systemic lupus erythematosus 3, secondary peritonitis 2, cardiac ascites 1, eosinophilic peritonitis 1 and tuberculosis peritonitis 1) to assess the clinical utility of ascitic fluid complements. The ascitic fluid level of complements 3c or C4 was significantly higher in patients with peritoneal carcinomatosis (32.8 +/- 10.2, 13.4 +/- 7.4 mg/dL) than in patients with sterile cirrhotic ascites (9.2 +/- 5.2, 4.5 +/- 3.9 mg/dL, p < 0.001), spontaneous bacterial peritonitis (8.2 +/- 4.1, 3.8 +/- 2.4 mg/dL, p < 0.001) or hepatocellular carcinoma (12.8 +/- 8.3, 5.6 +/- 4.4 mg/dL, p < 0.001). However, it was not significantly different from the miscellaneous disease group. To verify that ascites formation is not related to liver disease origin, diagnostic sensitivity, specificity and accuracy were 83.3%, 92.7% and 90.9%, respectively, by the ascitic fluid level of complement 3c higher than the cut-off value (20 mg/dl); or 60.4%, 89.8% and 84.3%, respectively, by the ascitic fluid level of complement 4 higher than the cut-off value (10 mg/dL). A direct correlation was found between the ascitic fluid protein level and the ascitic fluid complement 3c (r = 0.70) or complement 4 (r = 0.57) level. Based on results in this study, we can conclude that measuring ascitic fluid complements is clinically useful in disapproving the liver disease origin of ascites formation. However, it is of little value in diagnosing spontaneous bacterial peritonitis or hepatocellular carcinoma.