Effect of defensins on interleukin-8 synthesis in airway epithelial cells

Neutrophils play an important role in inflammatory processes in the lung and may cause tissue injury through, for example, release of proteinases such as neutrophil elastase. In addition to neutrophil elastase, stimulated neutrophils also release small nonenzymatic and cationic polypeptides termed defensins. The aim of the present study was to investigate whether defensins induce interleukin (IL)-8 expression in cells of the A549 lung epithelial cell line and in human primary bronchial epithelial cells (PBEC). Supernatants of defensin-treated A549 cells contained increased neutrophil chemotactic activity (16-fold) that was inhibited by antibodies against IL-8. Concurrently, within 3 and 6 h, defensins significantly increased the IL-8 levels in supernatants of both A549 cells (n = 6, P < 0.05 and P < 0.01, respectively) and PBEC (n = 4, P < 0.001 and P < 0.001, respectively). This defensin-induced increase was fully inhibited by the serine proteinase inhibitor alpha 1-proteinase inhibitor. In addition, defensins also increased IL-8 mRNA levels (12-fold); this increase was dependent on de novo mRNA synthesis and did not require protein synthesis. Furthermore, defensins did not affect IL-8 mRNA stability, indicating that the enhanced IL-8 expression was due to increased transcription. Our findings suggest that defensins, released by stimulated neutrophils, stimulate IL-8 synthesis by airway epithelial cells and thus may mediate the recruitment of additional neutrophils into the airways.

Pancreatitis-associated protein: a putative marker for pancreas graft rejection

BACKGROUND

Graft rejection is one of the major causes of graft loss after pancreas transplantation. Pancreatitis-associated protein (PAP) is synthesized by the pancreas due to pancreatic inflammation and has shown to be a good serum marker for injury of the pancreas. It may also be potentially useful in the early recognition of rejection and may thus improve pancreas survival.

METHODS

We retrospectively evaluated PAP as an early serum marker of pancreas graft rejection in a cross-sectional study in which immunohistochemical analysis of pancreas biopsies was undertaken using antibodies against PAP. PAP concentrations were also measured in sera of blood donors and in patients with renal failure, renal replacement therapy, kidney transplantation alone, and simultaneous pancreas-kidney transplantation.

RESULTS

All patients had elevated PAP serum levels compared with blood donors (median PAP: 22 ng/ml, range: 5-75 ng/ml; P<0.0001). Patients on renal replacement therapy had higher values than patients with renal failure (median: 420 ng/ml and 150 ng/ml, respectively). There was a strong inverse correlation between PAP levels and creatinine clearance (P<0.001). PAP values in simultaneous pancreas-kidney transplantation patients with histological rejection were significantly higher than values in those who were clinically stable (median: 925 ng/ml and 322 ng/ml, respectively; P=0.006). Rejection was significantly associated with PAP staining of acinar cell surface. There was also a significant correlation between surface positivity of staining and serum PAP levels (P=0.008). No positive PAP staining was observed in concurrently collected biopsies of renal allografts undergoing rejection.

CONCLUSIONS

Serum PAP levels appear to strongly correlate with creatinine clearance measurements. In patients with a pancreas-kidney transplantation, PAP may prove to be a useful biological and histological marker of pancreatic graft rejection.

Intracellular localization of the human receptor for the globular domains of C1q

This study was performed to determine the localization of the recently described receptor for the globular domain of C1q, gC1qR. In contrast to previous reports, we were not able to detect significant surface expression of gC1qR on Raji cells, monocytes, neutrophils, human or rat mesangial cells, the endothelial cell line EA.hy 926, or HUVEC using FACS analysis. Only by using digoxigenin-conjugated Abs could some surface staining of gC1qR be observed on rat mesangial cells and neutrophils. However, after permeabilizing these cells with saponin, a strong positive intracellular staining for gC1qR was observed by FACS, fluorescence microscopy on coverslips, and confocal laser scanning microscopic analysis. By reflection contrast microscopy and electron microscopy on ultrathin sections of permeabilized Raji cells, it was shown that gC1qR is present in double membranous cytoplasmic vesicles located in the proximity of the plasma membrane. To determine whether certain conditions could induce surface expression of gC1qR, Raji cells were either stimulated with T cell growth factor, LPS, or driven to apoptosis by incubation with fenretinide or by serum depletion. None of the conditions resulted in significant surface expression of gC1qR. Our hypothesis that gC1qR is not a surface molecule but a soluble molecule that is secreted by cells is supported by the observation that gC1qR is found in significant concentrations in supernatants of several cultured cells and in normal human and rat sera. Our results suggest that the recently described gC1qR is not a cell surface receptor, but a soluble binding protein with affinity for the globular heads of C1q. Excreted gC1qR might act as a potential fluid phase regulator of complement activation.

Intracellular localization of the human receptor for the globular domains of C1q

This study was performed to determine the localization of the recently described receptor for the globular domain of C1q, gC1qR. In contrast to previous reports, we were not able to detect significant surface expression of gC1qR on Raji cells, monocytes, neutrophils, human or rat mesangial cells, the endothelial cell line EA.hy 926, or HUVEC using FACS analysis. Only by using digoxigenin-conjugated Abs could some surface staining of gC1qR be observed on rat mesangial cells and neutrophils. However, after permeabilizing these cells with saponin, a strong positive intracellular staining for gC1qR was observed by FACS, fluorescence microscopy on coverslips, and confocal laser scanning microscopic analysis. By reflection contrast microscopy and electron microscopy on ultrathin sections of permeabilized Raji cells, it was shown that gC1qR is present in double membranous cytoplasmic vesicles located in the proximity of the plasma membrane. To determine whether certain conditions could induce surface expression of gC1qR, Raji cells were either stimulated with T cell growth factor, LPS, or driven to apoptosis by incubation with fenretinide or by serum depletion. None of the conditions resulted in significant surface expression of gC1qR. Our hypothesis that gC1qR is not a surface molecule but a soluble molecule that is secreted by cells is supported by the observation that gC1qR is found in significant concentrations in supernatants of several cultured cells and in normal human and rat sera. Our results suggest that the recently described gC1qR is not a cell surface receptor, but a soluble binding protein with affinity for the globular heads of C1q. Excreted gC1qR might act as a potential fluid phase regulator of complement activation.

Increased expression of IL-15 in the synovium of patients with rheumatoid arthritis compared with patients with Yersinia-induced arthritis and osteoarthritis

Recently, a new player in the cytokine network has been described that is produced by monocytes and can be detected in the rheumatoid synovium: interleukin-15 (IL-15). Since this cytokine may play a role in the accumulation and activation of T-cells, B-cells, and natural killer (NK) cells characteristic of synovial tissue (ST) from patients with rheumatoid arthritis (RA), the expression of IL-15 was studied in ST from RA patients in comparison with ST from patients with reactive arthritis (ReA) and osteoarthritis (OA) and the phenotype of IL-15-positive cells was determined. IL-15 expression was investigated by immunohistochemical analysis of ST from ten patients with RA, ten patients with Yersinia enterocolitica-induced ReA, and nine patients with OA. The immunohistological findings were quantified and the results obtained in the different patient groups were compared. To determine the phenotype of IL-15-expressing cells, double-labelling immunofluorescence was performed. The expression of IL-15 was significantly higher in ST from patients with RA than in ST from patients with ReA or OA. In double-label experiments, co-expression was observed with markers for macrophages, T-cells, and NK cells. The composition of the cellular infiltrate in the synovium of patients with RA might be partly explained by the specific increase in expression of IL-15 in rheumatoid ST. It can be speculated that IL-15 production by inflammatory cells other than macrophages may occur in the rheumatoid synovium.

Interferon-gamma induces biosynthesis of complement components C2, C4 and factor H by human proximal tubular epithelial cells

In a previous study the authors demonstrated that the production of complement component C4 by human kidney proximal tubular epithelial cells (PTEC) is upregulated by interferon gamma (IFN-gamma). In the present study the authors describe that PTEC in culture express both mRNA and protein of the IFN-gamma receptor complex, and that culture of PTEC with 1000 U/ml IFN-gamma for 72 h results in enhanced production not only of C4 (36.1 ng/10(6) cells), but also of C2 (10.8 ng/10(6) cells) and Factor H (17.5 ng/10(6) cells). Unstimulated PTEC produced 0.5 ng/10(6) cells, 0.5 ng/10(6) cells and 0.4 ng/10(6) cells of C2, C4 and Factor H, respectively. The upregulation of the three complement components was dose- and time-dependent and specific for IFN-gamma because the effect of IFN-gamma was abolished by a monoclonal antibody directed against IFN-gamma. Furthermore no effect of other cytokines was observed. The regulation of synthesis of C2, C4 and Factor H occurred at the transcriptional level as shown by semi-quantitative RT-PCR and dot-blot analysis. Taken together with the observation that in normal kidney tissue the tubuli express IFN-gamma receptor alpha-chain and a signal transducing protein, the present study implies that enhanced production of complement by PTEC may occur during a local immune response by in situ generation of IFN-gamma by infiltrating T-cells in the interstitium of the kidney.

The glomerular deposition of PAS positive material correlates with renal function in human kidney diseases

General agreement exists on the correlation of renal insufficiency with the severity of tubulointerstitial abnormalities in the biopsy. This could not be shown for the severity of glomerular pathology by semiquantitative methods. The relation between renal function and glomerular pathology was therefore evaluated in patients with various kidney diseases using quantitative measurements. Fifty-five patients and ten controls were studied. Histomorphometric measurements of renal biopsies were obtained for both frozen and paraffin sections and were correlated with serum creatinine values. The frozen sections were stained with an indirect immunoperoxidase technique using antibodies against collagen types I, IV, V, VI, laminin, fibronectin, decorin and heparansulphate proteoglycan core protein. The contribution of each component to the composition of the mesangial extracellular matrix was scored with a semiquantitative technique. All glomerular histomorphometric indices correlated with the severity of renal insufficiency expressed as serum creatinine at the time of biopsy. However, quantitative estimates of the glomerular deposition of periodic acid-Schiff positive extracellular matrix seemed to be the most important structural correlate of renal function (r = 0.524, p = 0.0001). Semiquantitative estimates of interstitial extracellular matrix accumulation were less correlated with renal function (r = 0.370, p = 0.01). The composition of the mesangial extracellular matrix did not differ in patients and controls, with the exception of the extent of laminin staining, which was significantly higher in patients. The extent of fibronectin staining in patients correlated with the severity of glomerular structural abnormalities. This study demonstrates that the severity of renal insufficiency in a variety of renal diseases correlates with the severity of glomerular pathology, when quantitative scoring is applied.

Possible role for CD40-CD40L in the regulation of interstitial infiltration in the kidney

Interstitial infiltration by mononuclear cells is a hallmark of most inflammatory kidney diseases, and the degree of infiltration is associated with disease progression. It has been demonstrated that proximal tubular epithelial cells (PTEC) are an important source of different cytokines/chemokines and thereby play a central role in the regulation of the local inflammatory response. CD40 is a cell surface receptor involved in immune regulation for which the ligand is expressed on activated T cells. By different staining methods, CD40 was found expressed in cryosections on the basolateral side of tubuli, as well as on the surface of an SV40-transformed PTEC line (PTEC-TRL) and on primary PTEC cultures. Cross linking CD40 receptor on these cultured cells, using a CD40L-transfected mouse fibroblast, resulted in strong up-regulation of the production of the chemokines IL-8, MCP-1 and RANTES. For IL-8 and MCP-1 production, the stimulation index after CD40 activation ranged from two- to sevenfold. Much stronger effects were observed for RANTES production, where levels remained undetectable (< 0.1 ng/ml) in non-stimulated cultures, whereas CD40 activation resulted in a strong production reaching 5 ng/ml in a 72-hour culture period. These data suggest that CD40L-CD40 interactions between infiltrating activated T cells and PTEC might be an important factor in the regulation of interstitial infiltration within the kidney.

The effect of sodium aurothiomalate on stimulated and non-stimulated migration by human neutrophils: the role of cyclic GMP

Preincubation of human neutrophils with aurothiomalate had little effect on random migration or chemotactic migration towards the chemotactic peptide fMLP. However, a strong enhancement of migration was observed when aurothiomalate was present in a concentration gradient; the effect of the drug was chemotactic rather than chemokinetic. Thiomalate also caused a chemotactic enhancement of migration but here a tenfold higher concentration of the drug was required as compared with aurothiomalate. Aurothiomalate caused an increase of cellular cGMP level, and inhibitors of guanylate cyclase inhibited the activating effect of aurothiomalate. Three specific antagonists of cGMP-dependent kinase (G-kinase) strongly inhibited aurothiomalate-induced migration of electroporated neutrophils. The results suggest that stimulation of migration by aurothiomalate is mediated by cGMP and a G-kinase. Monoclonal anti-IL-8 inhibited aurothiomalate-induced stimulation of migration. Though no increased release of IL-8 could be established upon exposure of neutrophils to aurothiomalate, it seems conceivable that the stimulating effect of aurothiomalate is mediated by IL-8.

Analysis of the synovial cell infiltrate in early rheumatoid synovial tissue in relation to local disease activity

OBJECTIVE

To define variations in the cellular infiltrate and in the expression of monokines in synovial tissue (ST) from rheumatoid arthritis (RA) patients with different durations of disease and different levels of disease activity.

METHODS

The immunohistologic features of synovial biopsy specimens from 31 patients with early RA (< 1 year) and 35 patients with longstanding RA (> 5 years) were compared. The possible associations between these features and local disease activity, as measured by the score for pain in the biopsied knee joint were also evaluated.

RESULTS

The immunohistologic features were not dependent on disease duration. We found a positive correlation between the scores for knee pain and the semiquantitative scores for the number of macrophages, as well as the expression of interleukin-6 and tumor necrosis factor alpha, whereas the correlation with the scores for CD4+ T cells was negative. Multivariate analysis showed that these correlations were highly statistically significant (P < 0.003).

CONCLUSION

The results do not support the view that inflammatory mechanisms in the synovial tissues of RA patients differ between early and late stages of the disease. The findings presented here are consistent with the concept that early RA is the result of a synovitis process of longer duration and that macrophage-derived cytokines play an important role in maintaining the clinical signs of inflammation.

Specificity of monoclonal antibodies against ABH and related structures tested by ELISA with synthetic glycoconjugates

We have tested 88 monoclonal antibodies with proposed specificities against ABH- and related antigens in an ELISA with synthetic oligosaccharide conjugates as coating substances. All mabs were tested for binding towards A-, B-, and H type I trisaccharides, the B disaccharide, and the proposed anti-A and -AB were also tested on A tetrasaccharide type I. Of the 50 mabs with proposed A- and/or B-specificity, 28 showed a specific reaction in our ELISA. Cross-reactivity with other ABH-antigens was observed for 7 of these 50 anti-A/B mabs and 15 of them did not react in the ELISA. Only 2 of the 17 mabs submitted as anti-H bound to H trisaccharide type I, one of them showed a polyspecific reactivity pattern, and the remaining 14 did not react with our type I antigen. Of the mabs with other than ABH-specificities only one, supposedly anti-P1, showed cross-reactivity with one of our coating antigens, in this case the B trisaccharide.

Efficient induction of apoptosis in cultured rat glomerular mesangial cells by dimeric monoclonal IgA anti-Thy-1 antibodies

Apoptosis of glomerular cells (GMC) has been observed in the early phase as well as the resolution phase of Thy-1 nephritis. Recently, we and others reported that IgG2a (ER4G) and IgG1 (OX7) monoclonal mouse anti-Thy-1 antibodies (anti-Thy-1 MoAb) are able to induce apoptosis of rat GMC in vivo. The purpose of this study was to investigate whether cross-linking of Thy-1 would influence the degree of apoptosis in cultured rat GMC using monomeric and dimeric IgA anti-Thy-1 MoAb. IgA anti-Thy-1 MoAb (ER4A) was generated by class switching of the IgG producing ER4 (ER4G) hybridoma. The ER4A clone spontaneously produces monomeric (m-ER4A) and dimeric IgA anti-Thy-1 MoAb *di-ER4A). Unaltered epitope specificity of ER4A was confirmed by blocking experiments of the binding of fluorescence labeled ER4G to cultured rat GMC with unlabeled ER4A on FACS. For the experiments of apoptosis, quiescent rat GMC were incubated for eight hours with medium alone or with medium in the presence of 10 micrograms/ml of m-ER4A, di-ER4A or control IgA MoAb of corresponding sizes. Apoptosis was assessed by morphological studies, agarose gel electrophoresis and quantitative FACS analyses using terminal deoxynucleotidyl transferase (TDT) method and the annexin V method. The TDT method detects specific-DNA nicking in apoptosis. The annexin V method detects early membrane changes during apoptosis. In morphological studies, cells incubated with m-ER4A and di-ER4A showed typical apoptotic features such as nuclear condensation and fragmentation. DNA isolated from the cells incubated with di-ER4A was cleaved into a distinctive ladder pattern compatible with apoptosis. In contrast, both medium alone and control IgA MoAb did not reveal detectable changes in morphological studies and agarose gel electrophoresis. In quantitative analyses by FACS using the TDT method and the annexin method, both m-ER4A and di-ER4A induced significantly higher percentages of apoptosis in rat GMC as compared to the controls. Furthermore, di-ER4A was considerably more efficient than m-ER4A in inducing apoptosis possibly through additional cross-linking of Thy-1 on the cell surface. This notion was confirmed by experiments, in which the addition of goat anti-mouse kappa antibodies enhanced apoptosis of rat GMC pre-sensitized with m-ER4A. Taken together, our results indicate that apoptosis of rat GMC by anti-Thy-1 antibodies is enhanced by cross-linking of Thy-1 on the cell surface. These studies are of importance for our understanding of mechanisms that may play a role in glomerular diseases.

Histamine-releasing activity in supernatants of mononuclear cells: contribution of monocyte chemotactic protein-1 activity compared with IgE-dependent activity

BACKGROUND

Supernatants of cultured human mononuclear cells contain factors that induce histamine release from basophils. Some of the histamine-releasing factors present are IgE-independent, but an IgE-dependent form has also been described. The IgE that does respond to the IgE-dependent histamine-releasing factor was defined as IgE+.

OBJECTIVE

This study was conducted to analyze the contribution of chemokines, such as monocyte chemotactic protein-1 (IgE-independent), to improve the detection of IgE-dependent histamine-releasing factor.

METHODS

Supernatants were prepared from mononuclear cells of three subjects. Monocyte chemotactic protein-1 content and histamine-releasing activity (HRA) were measured. Depletion of chemokine activity was carried out with heparin-Sepharose (Pharmacia, Uppasala, Sweden).

RESULTS

Replacing IgE- on basophils with IgE+ serum decreased the correlation between monocyte chemotactic protein-1 and histamine release (rho = 0.80, n = 280 vs p = 0.12, n = 18; p for difference between p values; < 0.05). After depletion of chemokines in three supernatants derived from mononuclear cells, IgE-dependent HRA was still present.

CONCLUSION

We conclude that in supernatants derived from mononuclear cells, the IgE-independent HRA masks the IgE-dependent HRA. The latter can be more clearly detected after depletion of chemokine activity with heparin-Sepharose.

Induction of microhematuria by an IgA isotype switch variant of a monoclonal anti-Thy-1.1 antibody in the rat

IgA nephropathy (IgAN) is a chronic form of glomerulonephritis (GN) characterized by the deposition in the glomerular mesangium of mainly IgA. An experimental form of mesangial proliferative GN can be induced in rats by either polyclonal or monoclonal antibodies against Thy-1.1, a glycoprotein present on the surface of MC. The IgG-mediated renal inflammation is complement dependent and associated with influx of platelets and monocytes. In the present study we switched an IgG2a anti-Thy-1.1 (ER4G) producing hybridoma to an IgA anti-Thy-1.1 (ER4A) producing clone and analyzed the effects of IgA anti-Thy-1.1 in rats. FPLC analysis by gel filtration revealed that the IgA produced by the hybridoma cells was mainly dimeric and polymeric. Infusion of rats with purified ER4A (1 mg/kg) resulted in the deposition of IgA in a mesangial pattern in the glomeruli, similar to that found with ER4G. While administration of ER4G resulted in proteinuria, no significant urinary protein excretion was found in rats treated with ER4A. However, significant microhematuria was observed in rats receiving either ER4A or ER4G. Furthermore, the administration of ER4A was not accompanied by activation of complement, and no significant influx of monocytes or polymorphonuclear leukocytes was observed in contrast to the rats receiving ER4G. We conclude that microhematuria is selectively induced in Wistar rats by mouse IgA anti-Thy-1.1 without detectable complement-mediated injury to MC. These studies may be of importance in understanding the mechanisms leading to IgAN in patients.

Alternative splicing of IgA Fc receptor (CD89) transcripts

An alternatively spliced CD89 transcript is present in peripheral blood mononuclear cells (PBMC) and U937 cells. The alternatively spliced CD89 mRNA species lacks the exon 4 sequence, encompassing 288 nucleotides, that encodes the extracellular membrane-proximal immunoglobulin-like domain (EC2).

Carrier detection by microsatellite haplotyping in 10 properdin type 1-deficient families

Properdin deficiency carrier identification is relevant, because properdin-deficient persons have an increased risk of contracting meningococcal disease. Vaccination against meningococcal disease at a young age may provide protection. Accurate detection of this deficiency is needed. Microsatellite haplotyping with the PFCI and PFC2 markers closely linked to the properdin gene locus at Xp11.3-Xp11.23 may offer an easy and accurate identification of carriers of the properdin deficiency gene. The chance to study 91 relatives belonging to 10 families with complete (type 1) properdin deficiency offered a unique opportunity to assess whether properdin type 1 deficiency is associated with a distinct microsatellite haplotype. Haplotyping with the closely linked PFC1 and 2 markers yielded five different haplotypes, which did not support the concept of a founder effect. Among the 28 women carriers, two had normal properdin levels and in five the PFC1,2 polymorphism was not informative owing to homozygosity. Extending the microsatellite haplotyping with three additional markers (DXS1126, DXS426 and DXS7) yielded informative haplotypes in all meioses. We concluded that microsatellite haplo-typing using five markers in close proximity to the properdin gene locus is an accurate method of detecting carriers of the properdin deficiency gene and of properdin-deficient persons within a family at a young age.

Development and standardization of solid phase assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). A report on the second phase of an international cooperative study on the standardization of ANCA assays

Anti-neutrophil cytoplasmic antibodies (ANCA) are diagnostic markers for systemic vasculitis. They are classically detected by an indirect immunofluorescence test using normal donor neutrophils as substrate. This assay lacks antigenic specificity and is not quantitative. The 'EC/BCR Project for ANCA Assay Standardization' is an international collaboration study with the aim to develop and standardize solid phase assays for ANCA detection. In this part of the study the isolation and characterization of proteinase-3 and myeloperoxidase, the two main target molecules for ANCA, and the development and standardization of ELISAs with these antigens are described. Six laboratories successfully isolated purified proteinase-3 preparations that could be used. Three of these preparations, together with one myeloperoxidase preparation, were subsequently used for ANCA testing by ELISA. The ELISA technique was standardized in two rounds of testing in the 14 participating laboratories. The coefficient of variation of these new assays decreased from values of approx. 50% in the first round to approx. 20% in the second round. We conclude that purified proteinase-3 and myeloperoxidase can be used in standardized ELISAs for ANCA detection. Whether such procedures offer advantages over the IIF test will be determined in a prospective clinical study.

Deficient IgA1 immune response to nasal cholera toxin subunit B in primary IgA nephropathy

Twelve IgA nephropathy (IgAN) patients and 18 controls were immunized with novel protein antigens, cholera toxin subunit B (CTB) via the nasal route and keyhole limpet hemocyanin (KLH) subcutaneously. Antibody secreting cells and antibody response in body fluids were determined by ELISPOT assay and ELISA, respectively. Analysis of variance showed, in contrast to controls (P < 0.001), no CTB-specific IgA response in the nasal washes of patients with IgAN. Significantly lower numbers of CTB-specific antibody-secreting cells in peripheral blood (P < 0.001) and CTB-specific antibodies in plasma (P < 0.005) were found in IgAN, both restricted to the IgA1 subclass. The proportions of CTB-specific IgA1-secreting cells in bone marrow aspirates correlated significantly with the corresponding ratios in plasma, with significantly lower values (P < 0.005) in IgAN as compared to controls. These results support the existence of a "mucosa-bone marrow axis" in humans, but no dysregulation of this axis was found in IgAN. The deficient mucosal IgA immune response to CTB observed in this study after primary mucosal immunization indicates that patients with IgAN have a defective immune response when challenged intranasally. These patients may depend on more frequent and/or prolonged antigen encounter at mucosal sites before efficient mucosal immunity is established. Repeated seeding of antigen-specific cells to secondary lympoid organs could result secondarily in the relative hyperresponsiveness found in IgAN upon reactivation by parenteral immunization.

Heterozygous and homozygous factor H deficiency states in a Dutch family

Factor H, a 150-kD protein, is an important down-regulating protein of the alternative pathway of the complement system. Presently, only 15 persons, representing seven families, have been described with homozygous factor H deficiency. Deficiency of this protein, inherited as an autosomal recessive trait and resulting in uncontrolled breakdown of C3, results in depletion of components of the alternative pathway (factor B, properdin) and of the terminal pathway (C5), and is associated with the onset of bacterial infections, glomerulonephritis and systemic lupus erythematosus (SLE). The proband of the family in this study suffered from subacute cutaneous lupus erythematosus and had had meningococcal meningitis due to serogroup X. She had a complete factor H deficiency at the protein level as determined by Western blotting. Among 21 relatives of the proband studied, encompassing three generations, 10 had low factor H levels, including the two children of the proband, indicating a heterozygous factor H deficiency state. In serum samples of the proband and 11 relatives prospectively studied, a strong correlation of factor H levels with C3, C3 haemolytic activity, factor B and properdin levels (P < 0.0001) was found. Alternative pathway protein levels were significantly lower (Mann-Whitney test; Z values 3.6-2.7) in sera from the four heterozygous relatives studied than in sera from the seven non-deficient relatives. In addition, a defect of the 37/42-kD H-related protein was found in the proband and two of 21 relatives, compared with four of 40 controls. A defect of the 24/29-kD H-related protein was present in one of 21 relatives studied and in none of the 40 controls.

Expression of the activation antigen CD27 in rheumatoid arthritis

Differentiation of CD4+ T-cells is reflected by the change from the CD45RA+CD27+ phenotype via CD45RO+CD27+ to the CD45RO+CD27- phenotype. To provide insight into the migration and activation of T-cells at the site of inflammation in rheumatoid arthritis (RA), CD27 expression by T-cells in peripheral blood (PB), synovial fluid (SF), and synovial tissue (ST) as well as the levels of the soluble form of CD27 (sCD27) in plasma and SF were studied in patients with RA. Since CD4+CD27+ T-cells are involved in providing helper activity for B-cells, we also investigated the levels of rheumatoid factors in serum and SF in relation to CD27 expression. The mean level of sCD27, which is produced by CD27+ cells, and the mean percentage of CD27 T-cells within the CD4+CD45RA- subset were higher in SF than in PB. SF sCD27 levels were higher in the patients with RA than in the patients with osteoarthritis, who served as controls. In ST infiltration by CD4+CD45RO+CD27+ T-cells, could be demonstrated in the rheumatoid perivascular lymphocytic aggregates with a relative increase in the percentage of CD27- T-cells in the diffuse lymphocytic infiltrate. The sCD27 levels and the percentages of CD4+CD27+ cells in SF correlated positively with the levels of rheumatoid factors in serum and SF. The findings presented in this study suggest a continuous influx of preactivated CD4+CD45RO+CD27+ cells from the PB into the rheumatoid ST and further activation and differentiation to CD4+CD45RO+CD27- cells in situ, followed by migration to the SF. These activated T-cells are likely to play a role in synovial inflammation.