Different mechanisms by which anti-DNA MoAbs bind to human endothelial cells and glomerular mesangial cells.

The mechanisms by which anti-DNA MoAbs derived from MRL-lpr/lpr mice, bind to human umbilical vein endothelial cells (HUVEC) and glomerular mesangial cells were studied using a cellular ELISA. DNAse-treatment of either the MoAb or HUVEC followed by reconstitution with DNA and/or histones was performed to determine whether DNA and histones mediated such binding. It was found that MoAb410 bound to HUVEC and mesangial cells in the form of preformed DNA/anti-DNA immune complex, and such binding was facilitated by histones. In contrast, MoAb 152 bound directly to cell membrane-associated DNA, and adding DNA to MoAb 152 reduced its cellular binding. DNA binds endothelial cell surface and histones enhance the binding of both MoAb 410 and MoAb 152 to HUVEC by increasing cell membrane-associated DNA. Finally, the degree of MoAb binding to HUVEC is critically influenced by the relative concentrations of antibody, DNA, and histones.     

Incidence of childhood diabetes mellitus in Yorkshire, northern England, is associated with nitrate in drinking water: an ecological analysis

Summary The relationship between the incidence of childhood-onset insulin-dependent diabetes mellitus and levels of nitrate in drinking water in the former Yorkshire Regional Health Authority was investigated by means of an ecological analysis. A population-based register contributed 1797 0–16-year-olds diagnosed with diabetes between 1978 and 1994. Nitrate data were based on 9330 samples of drinking water tested between 1990 and 1995 in 148 water supply zones, for which 1991 census small area statistics were taken on population density, ethnicity and socio-economic status. Diabetes incidence was positively associated with raised mean nitrate levels with a standardised incidence ratio of 115 in zones with greater than 14.85 mg · l^–1 (χ² = 26.81, 1 df, p < 0.001). Significant negative trends were found between standardised incidence ratios and proportion of non-whites in the population (χ² = 33.57, 1 df, p < 0.001), childhood population density (χ² = 30.81, 1 df, p < 0.001) and the Townsend deprivation score (χ² = 33.89, 1 df, p < 0.001). Poisson regression modelling, adjusting for the other factors, showed a significant increase in relative incidence rate ratio from a baseline of 1 at nitrate levels below 3.22 mg · l^–1 to 1.27 (95 % confidence interval 1.09,1.48) for mean nitrate levels above 14.85 mg · l^–1. An association between higher nitrate levels in domestic drinking water and incidence of childhood diabetes has been demonstrated. This was not explained by the ethnic composition of the population, population density or socioeconomic status. Nitrate in drinking water may be a precursor of chemicals which are toxic to the pancreas. [Diabetologia (1997) 40: 550–556] Received: 24 October 1996 and in revised form: 20 December 1996     

Crossed inhibition of the soleus H reflex during passive pedalling movement

We hypothesized that sensory input from the moving leg induces presynaptic inhibition of the soleus H reflex pathway in the contralateral stationary leg. The results showed a crossed inhibition during passive pedalling movement of the leg, which was not removed by low levels of tonic contraction of soleus in the stationary leg. The inhibition was correlated exponentially to the rate of the movement (R²=0.934, P<0.05) and was not dependent on the quadrants through which the moving leg was passing. Static flexion of the stationary leg caused ipsilateral inhibition of the reflexes (t=5.590, P<0.05), independent of the orientations of the other leg. We concluded that sensory inflow from the moving leg induces presynaptic inhibition in the stationary leg, that a complex transformation of the sensory input in the spinal cord or brain underlies the tonic crossed inhibition and phasic ipsilateral inhibition, and that descending motor commands exert a powerful control over these sensorimotor modulatory mechanisms.     

Fine specificity of autoantibodies to calreticulin: epitope mapping and characterization

Extracellular calreticulin (CRT) as well as anti‐CRT antibodies have been reported in patients with various autoimmune disorders and CRT has been implicated in ‘epitope spreading’ to other autoantigens such as the Ro/SS‐A complex. In addition, antibodies against parasite forms of the endoplasmic reticulum chaperone, CRT, have been found in patients suffering from onchocerciasis and schistosomiasis. In this study, we screened sera for anti‐CRT antibodies from patients with active and inactive systemic lupus ertythematosus (SLE) and primary or secondary Sjögren’s syndrome. Approximately 40% of all SLE patients were positive for anti‐CRT antibodies. The antigenic regions of CRT were determined using full length CRT and fragments of CRT prepared in yeast and Escherichia coli, respectively. Synthetic 15mer peptides corresponding to the major autoantigenic region of CRT (amino acids 1–289), each one overlapping by 12 amino acids, were used to map the B cell epitopes on the CRT protein recognized by autoimmune sera. Major antigenic epitopes were found to be associated with the N‐terminal half of the protein in 69% of the SLE sera from active disease patients, while the C‐domain was not antigenic. Major epitopes were found to be reactive with antibodies in sera from SLE patients with both active and inactive disease, spanning different regions of the N and P‐domains. Sera from both healthy and disease controls and primary Sjögren’s syndrome patients were non‐reactive to these sequences. Limited proteolysis of CRT with two major leucocyte serine proteases, elastase and cathepsin G, demonstrated that an N‐terminal region of CRT is resistant to digestion. Interestingly, some of the epitopes with the highest reactivity belong to the fragments of the protein which bind to C1q and inhibit complement activation. Whether C1q association with CRT is a pathological or protective interaction between these two proteins is currently under investigation.     

Alveolar capillary dysplasia with misalignment of the pulmonary veins and hypoplastic left heart sequence caused by an in frame deletion within FOXF1

Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACDMPV) is a rare, autosomal dominant disorder of interstitial lung development, leading to pulmonary hypertension, and death in infancy. Associated features include malformations of the heart, gastrointestinal tract, and genitourinary system. ACDMPV is caused by heterozygous variants in the FOXF1 gene or microdeletions involving FOXF1. We present a male infant with ACDMPV, hypoplastic left heart sequence (HLHS), duodenal atresia, and imperforate anus due to a de novo, in frame deletion in FOXF1: c.209_214del (p.Thr70_Leu71del). Previous reports have suggested that microdeletions involving FOXF1 are associated with ACDMPV with congenital heart defects, including HLHS, gastrointestinal atresias, and other anomalies; whereas likely pathogenic variants within FOXF1 have not been reported with ACDMPV and HLHS. This is the first patient reported with ACDMPV, HLHS, imperforate anus, and duodenal atresia associated with a likely pathogenic variant in the FOXF1 gene.     

Anti-idiotype and immunosuppressant treatment of murine lupus.

The effect of the administration of a xenogeneic anti-idiotype antibody (anti-Id33) to a cross-reactive idiotype (Id33) present on anti-dsDNA antibody was examined in 6-week-old (NZB/NZW) F1 (BWF1) female mice. The administration of anti-Id33 led to a transient reduction in immunoglobulins expressing Id33, followed by a rise at 30 and 34 weeks that was significantly higher than in untreated mice (P less than 0.05). Likewise, anti-dsDNA antibody levels were significantly higher at 10 and 18 weeks than in untreated mice (P less than 0.01). No differences were seen in survival to 40 weeks, proteinuria or the severity of glomerulonephritis. Concurrent administration of cyclosporin A (CyA) with anti-Id33 markedly ameliorated glomerular injury and proteinuria and improved survival. By contrast, glomerular injury, proteinuria and survival were worse in mice treated with cyclophosphamide plus anti-Id33, compared with untreated mice. Neither CyA nor cyclophosphamide treatment, when given with anti-Id33 altered serum levels of anti-dsDNA, anti-ssDNA or Id33+ immunoglobin, compared with untreated mice. The different effects of CyA and cyclophosphamide on T lymphocytes and their discrepant effects on glomerular injury when given with anti-Id33 in this model lead us to postulate a role for T lymphocytes in the glomerular injury of BWF1 lupus.