Programmed Cell Death of Peripheral Blood B Cells Determined by Laser Scanning Cytometry in Sjögren’s Syndrome with a Special Emphasis on BAFF

Functionally impaired B cells play an important role in the pathogenesis of Sjögrens syndrome (SS). The aim of the study was to investigate the apoptosis susceptibility of peripheral blood B cells from patients with SS and the impact of B cell activating factor (BAFF) on the apoptosis capability of these cells in correlation with IgG production. Peripheral blood B cells were isolated and stained for apoptosis markers (Bax, Bcl-2) and members of the TNF-R superfamily, CD95 and CD40. The apoptosis frequency of cells bearing these markers were assessed. Also, the apoptosis capability of cultured B-lymphocytes was investigated in medium alone, with anti-CD95 or with soluble BAFF. Quantitative ELISA was performed to detect plasma levels of sBAFF. Furthermore, the level of circulating B-cell cytokines was measured. BAFF levels were compared between patients with normal and elevated IgG levels. In SS, Bcl-2 positive B cell counts were significantly higher then in controls, also in this population the apoptosis frequency was reduced. Apoptosis within Bax+ and CD40+ B cells were significantly decreased in patients. BAFF induced a significant antiapoptotic effect in SS; also this effect was clearly evident in B cells from SS with hypergammaglobulinaemia. Plasma BAFF levels were significantly higher in SS, mostly in patients with hypergammaglobulinaemia. Plasma B-cell cytokines were raised in SS. In Sjögrens syndrome B cells, a general antiapoptotic tendency might lead to prolonged B-cell survival driven at least partly by elevated levels of BAFF and supposedly by B-cell cytokines. Also, the exaggerated BAFF stimulation might lead to excessive immunoglobulin production. The B-cell apoptosis defects, the increased BAFF levels—correlating with hypergammaglobulinaemia—together with the raised B-cell cytokine levels indicates the disturbed B-cell biology in the disease.     

Arterial hypertension and sleep apnoea: effect of the angiotensin-converting enzyme (ACE) Inhibitor cilazapril on continuously measured blood pressure during sleep and wakefulness

SUMMARY  Male patients with arterial hypertension and obstructive sleep-related breathing disorders (mean age 50 y, Body Mass Index (BMI) 32.4 kg m^-2, Respiratory Disturbance Index (RDI) 47.2 and systolic/diastolic blood pressure (SBD/DBD) 162/103 mmHg) were examined before and after 8 days of treatment with the long-acting angiotensin-converting-enzyme (ACE) inhibitor cilazapril 2.5 mg vs. placebo in a double-blind design with parallel groups. Cardiorespiratory polysom-nography was carried out at night; during daytime wakefulness patients submitted to examinations of physical and mental exertion. Cilazapril reduced the mean pressure during the entire examination period (day and night) by 9.55 (SD±7.13) mmHg, compared to 4.57 (SD ±7.20) mmHg for placebo ( P < 0.006), independently from systematic changes of heart rate ( x = -3.3 and -3.5 bpm, respectively). During REM sleep, mean arterial pressure was significantly reduced by 8.63 (SD ±10.1) mmHg, compared to a reduction on placebo of 3.17 (SD 9.6) mmHg ( P = 0.023). Under psychometric strain, the mean arterial pressure was reduced by 15.31 (SD ±8.7) mmHg with cilazapril; under placebo medication by 6.19 (SD ±7.3) mmHg ( P < 0.0001). Heart rate was not significantly changed.     

COMMENTS

Human spermatogenesis is regulated by a network of genes located on autosomes and on sex chromosomes, but especially on the Y chromosome. Most results concerning the germ cell function of the Y genes were obtained by genomic breakpoint mapping studies of the Y chromosome of infertile patients. Although this approach has the benefit of focussing on those Y regions that contain most likely the Y genes of functional importance, its major drawback is the fact that fertile control samples were often missing. In fertile men, molecular and cytogenetic analyses of the Y chromosome has revealed highly polymorphic chromatin domains especially in the distal euchromatic part (Yq11.23) and in the heterochromatic part (Yq12) of the long arm. In sterile patients cytogenetic analyses mapped microscopically visible Y deletions and rearrangements in the same polymorphic Y regions. The presence of a Y chromosomal spermatogenesis locus was postulated to be located in Yq11.23 and designated as AZoospermia Factor (ZF). More recently, molecular deletion mapping in Yq11 has revealed a series of microdeletions that could be mapped to one of three different AZF loci: AZFa in proximal Yq11 (Yq11.21), AZFb and AZFc in two non‐overlapping Y‐regions in distal Yq11 (Yq11.23). This view was supported by the observation that AZFa and AZFb microdeletions were associated with a specific pathology in the patients' testis tissue. Only AZFc deletions were associated with a variable testicular pathology and in rare cases AZFc deletions were even found inherited from father to son. However, AZFc deletions were found with a frequency of 10–20% only in infertile men and most of them were proved to be “de novo”, i.e. the AZFc deletion was restricted to the patient's Y chromosome. Based mainly on positional cloning experiments of testis cDNA clones and on the Y chromosomal sequence now published in GenBank, a first blueprint for the putative gene content of the AZFc locus can now be given and the gene location compared to the polymorphic DNA domains. This artwork of repetitive sequence blocks called AZFc amplicons raised the question whether the AZFc chromatin is still part of the heterochromatic domain of the Y long arm well known for its polymorphic extensions or is decondensed and part of the Yq11.23 euchromatin? We discuss also the polymorphic DAZ gene family and disclose putative origins of its molecular heterogeneity in fertile and infertile men recently identified by the analyses of Single Nucleotide Variants (SNVs) in this AZFc gene locus.     

A functional study of low molecular weight IgM from patients with autoimmune disease

High levels of low molecular weight (LMW) IgM in certain diseases are associated with clinical and laboratory indices which reflect the severity of the disease. These associations suggest that LMW IgM may play an important role in the immunopathogenesis of these diseases. To further approach the question concerning the functional activity of LMW IgM in disease, a panel of LMW IgM and high molecular weight (HMW) IgM preparations with or without rheumatoid factor (RF) activity were used to investigate their antibody binding activity and their effector function. It was found that LMW IgM-RF and HMW IgM-RF had a similar binding capacity to Fc fragment as there was no significant difference in the affinity index between them. It further showed that the rate of activation and total amount of utilization of complement by LMW IgM and HMW IgM was similar, although the mean fluorescence of C3 deposition by IgM-RF and HMW IgM-RF was slightly higher than that of LMW IgM-RF and other control RF antibodies. However, the current study demonstrated that LMW IgM had strong neutrophil activating properties when compared with HMW IgM. These findings suggest that one mechanism of LMW IgM contributing to the immunopathogenesis of RA may be due to the formation of circulating immune complex ( CIC) by LMW IgM with subsequent activation of neutrophils. Whether LMW IgM has other functional activity in disease is unclear and needs further investigation.     

Chimeric Viruses Expressing Primary Envelope Glycoproteins of Human Immunodeficiency Virus Type I Show Increased Sensitivity to Neutralization by Human Sera

We constructed a number of HXB2 viruses chimeric for the gp120 glycoprotein derived from a number of viable molecular clones obtained from a primary isolate. Comparative biological characterization of the parental primary viruses with the gp120.HXB2 chimeras demonstrated identical patterns of cell tropism and cytopathicity. Furthermore, both parental and chimeric viruses were insensitive to neutralization by sCD4 and a panel of conformation-dependent monoclonal antibodies, demonstrating that transfer of the gp120 protein alone was sufficient to confer a “neutralization-resistant” phenotype to the T-cell-adapted clone HXB2. We assessed the contribution of gp120 epitopes to the neutralizing immune response by comparing the sensitivity of these viruses to neutralization by a panel of sera from HIV-infected individuals. Seven of eleven sera tested were able to neutralize HXB2 and two or more of the chimeric viruses; in contrast, only one serum neutralized more than one of the parental primary virus clones. The association of gp120–gp41 envelope at the surface of infected PBMC cultures was measured in the presence or absence of soluble CD4. No differences in CD4-induced gp120 dissociation were seen between the chimeric and parental virus-infected cultures. Since gp120 conformation appeared the same between primary and chimeric viruses, we suggest that the ability of human sera to neutralize the chimeric viruses may be mediated by epitopes within gp41.     

Cardiovascular Effects of Fumonisins in Swine

Fumonisins, mycotoxins produced by Fusarium moniliforme, inducehepatic damage and acute lethal pulmonary edema in swine. Weexamined the cardiovascular effects of short-term fumonisinexposure in anesthetized and conscious male cross-bred pigsweighing 30–36 kg. Culture material containing fumonisinsat 20 mg/kg/day (fumonisin B₁ and B₂ backbone) was added tothe feed of treated pigs (n = 5) for 7 days, while control pigs(n = 5) were fed a diet free of fumonisins. On Day 8, pigs wereanesthetized with halothane and instrumented with Swan-Ganzcatheters to facilitate hemodynamic measurements. Mean pulmonaryartery pressure, central venous pressure, heart rate, cardiacoutput, and electrocardiographic variables were recorded andstroke volume was calculated. All measurements were repeatedat least 18 hr after recovery from anesthesia. Pigs fed fumonisinshad a significant increase in mean pulmonary artery pressure,accompanied by decreased heart rate, cardiac output, and mixedvenous oxygen tension. The electrocardiogram was normal, andthere was no evidence of pulmonary edema formation either histologicallyor by altered lung wet/dry weights. This study suggests thatpulmonary hypertension caused by hypoxic vasoconstriction maybe associated with the pulmonary edema observed in fumonisintoxicity.     

Immune Function and Host Defense in Rodents Exposed to 60-Hz Magnetic Fields

This study was conducted to evaluate the influence of sub-chronicexposure to pure, linearly polarized 60-Hz magnetic fields (MF)on the host immune response in mice. The experimental designwas as follows: three groups were exposed continuously (18.5hr/day) to MF at field strengths of 0.02, 2, or 10 gauss (G),one group was exposed intermittently (1 hr on/l hr off) to MFat a field strength of 10 G, and one group served as a shamcontrol. Experimental endpoints included spleen and thymus weightsand cellularity, antibody-forming cell (AFC) response, delayed-typehypersensitivity (DTH) response, splenic lymphocyte subset analysis, susceptibility to infection with Listeria monocytogenes,and natural killer (NK) cell activity. No differences in bodyweight, lymphoid organ weight, or lymphoid organ cellularitywere ob served in any MF-exposed group in comparison to shamcontrols. Likewise, no statistically significant differenceswere found in com parisons of AFC responses. Isolated statisticallysignificant differ ences from control were observed in MF-exposedmice in the DTH assay, although no clear dose-related patternof altered activity was seen. Splenic lymphocyte subset parametersexamined were within normal limits in all groups, and no differencesbetween control and MF-exposed mice were found. Host resistanceto bacterial infection was not altered at any MF exposure examinedin this study. Finally, although apparently dose-related, statisticallysignificant alterations were observed in an initial study ofNK cell function, repeat studies failed to demonstrate a consistentpattern of alteration.