Increased binding of concanavalin A to alpha 2-macroglobulin, IgM and IgG from cystic fibrosis plasma

Usefulness of serum IgG4 in the diagnosis and follow up of autoimmune pancreatitis: A systematic literature review and meta-analysis

High circulating serum immunoglobulin G4 (IgG4) levels have been proposed as a marker of autoimmune pancreatitis (AIP). The aim of the present study was to review the data existing in the English literature on the usefulness of the IgG4 serum levels in the diagnosis and follow up of patients with AIP. A total of 159 patients with AIP and 1099 controls were described in seven selected papers reporting the usefulness of serum IgG4 in diagnosing AIP. In total, 304 controls had pancreatic cancer, 96 had autoimmune diseases, and the remaining 699 had other conditions. The summary receiver-operating characteristic curve analysis was carried out by means of Meta-DiSc open-access software. Serum IgG4 showed good accuracy in distinguishing between AIP and the overall controls, pancreatic cancer and other autoimmune diseases (area under the curve [+/- SE]: 0.920 +/- 0.073, 0.914 +/- 0.191, and 0.949 +/- 0.024, respectively). The studies analyzed showed significantly heterogeneous specificity values in each of the three analyses performed. The analysis of the four studies comparing AIP and pancreatic cancers also showed significantly heterogeneous values of sensitivities and odds ratios. Regarding the usefulness of IgG4 as a marker of efficacy of steroid treatment, a decrease in the serum concentrations of IgG4 was found in the four available studies. The serum IgG4 subclass is a good marker of AIP, and its determination should be included in the diagnostic workup of this disease. However, the heterogeneity of the studies published until now means that more studies are necessary in order to better evaluate the true accuracy of IgG4 in discriminating AIP versus other autoimmune diseases.

Effect of multiple sclerosis alpha 2-macroglobulin on mitogen induction of lymphocyte proliferation

Electrophoretic studies on microheterogeneity of alpha 2-macroglobulin (alpha 2M) have revealed the presence of an abnormal acidic form of alpha 2M in multiple sclerosis (MS). In the present study we have characterized alpha 2M chemically and compared the inhibitory effect of MS and normal alpha 2M on the mitogen induction of lymphocyte proliferation. The antitrypsin activity and total reducing sugar content of MS alpha 2M were comparable with those of normal alpha 2M. However, the sialic acid content of MS alpha 2M was found to be significantly higher than that of normal alpha 2M. In agreement with previous studies, normal alpha 2M was found to inhibit the mitogen induction of lymphocyte proliferation in more than 90% cell cultures. However, MS alpha 2M was found to inhibit the mitogen-induced lymphocyte proliferation in less than 35 percent cell cultures. The effects of MS or normal alpha 2M on the lymphocyte cultures of either groups were found to be apparently the same. The possible explanations for the loss of the above-mentioned inhibitory effect of MS alpha 2M have been discussed.

Glycoproteins in cystic fibrosis: a lectin binding study

Ten lectins have been used to detect glycoproteins, after SDS polyacrylamide gel electrophoresis and gel isoelectric focusing, in fibroblasts, red cell membranes, urine, and plasma of patients and obligate heterozygotes with cystic fibrosis. No disease specific changes were detected but considerable individual variation was observed, some of which was attributed to known genetic polymorphisms unrelated to cystic fibrosis.

Cobalamin R binder as a possible model molecule for glycoprotein study in cystic fibrosis

The isoprotein pattern of semi-purified R binder (an acidic glycoprotein which binds cobalamin) from saliva and sera of 8 cystic fibrosis patients was compared to that of R binder from samples of 5 healthy children. In cases of cystic fibrosis, the mean isoelectric point of salivary R binder was increased from 3.78 up to 4.34 and its microheterogeneity was reduced. These significant physicochemical modifications were not observed with R binder from cystic fibrosis sera and they did not correlate with the beta-galactosidase, alpha-mannosidase, alpha-L-fucosidase nor neuraminidase activity of saliva. We propose the R binder as a model molecule to study the glycoprotein metabolism in cystic fibrosis since it contains 30-40% carbohydrate, is easily complexed with cyano[57Co]cobalamin and is present in most tissues and fluids of the human organism.

Dolichyl phosphate-mannosyltransferase and dolichyl phosphate-N-acetylglucosaminyltransferase activities in liver preparations from normal controls and patients with cystic fibrosis and diabetes mellitus

Optimal assay conditions have been determined in human liver preparations for the catalytic transfer of mannose and N-acetylglucosamine from GDP-mannose and UDP-N-acetylglucosamine, respectively, to dolichyl phosphate. Both enzymatic reactions have an absolute requirement for divalent cation (5 mmol/l Mn2+ optimal), detergent (Triton X-100 or Nonidet P-40) and dolichyl phosphate (as acceptor substrate) and both reactions have optimal activity at a pH value of 7.8. Preliminary characterization of the glycolipid products for both enzymatic reactions indicates that phosphorylated dolichol is the major acceptor substrate for radiolabeled mannose and N-acetylglucosamine. The activity levels and specific activities of dolichyl phosphate-mannosyltransferase are comparable in liver homogenates from normal controls and patients with cystic fibrosis and diabetes mellitus. The activity levels and specific activities of dolichyl phosphate-N-acetylglucosaminyltransferase are comparable in liver homogenates from normal controls and patients with cystic fibrosis and diabetes mellitus but considerably lower than the activity levels of dolichyl phosphate-mannosyltransferase. It appears that two of the initial steps of the lipid-mediated glycosylation pathway are normal in livers from patients with cystic fibrosis and diabetes mellitus.

Characterization of alpha 2-macroglobulin from plasma of cystic fibrosis patients and controls

The physical, kinetic, and isoelectric focusing properties of native alpha 2-macroglobulin from cystic fibrosis and control plasmas were studied. No differences were found in the esterolytic activity levels of control, obligate heterozygote, and cystic fibrosis plasmas. Stability studies indicated that both control and cystic fibrosis alpha 2-macroglobulin retained full activity for at least 8 months at -20 degrees C, a week at 0-4 degrees C, 11 hr at 50 degrees C, and showed no differences in thermostability at several preincubation temperatures. The microheterogeneity of native alpha 2-macroglobulin was studied by column isoelectric focusing of five control and five cystic fibrosis plasmas. The number and pI values of the isoelectric forms between pH 4.5-8.0 were quite similar for both groups even though consistently less cystic fibrosis alpha 2-macroglobulin activity was recovered after isoelectric focusing.

Systematic study of the hydrolysis of 4-methylumbelliferylguanidinobenzoate in plasma from patients with cystic fibrosis and controls

In contrast to the original reports by others, the hydrolysis of 4-methylumbelliferylguanidinobenzoate ((MUGB), and active-site titrant of serine proteases, was found not to be significantly different in plasma samples from patients with cystic fibrosis (CF), obligate heterozygotes, and normal controls. Since the steady-state turnover of substrate is the dominant term of MUGB hydrolysis, the assay in its present form does not meet the requirements of an active-site titration. The reproducibility and reliability of the assay are hampered by (1) high blank values due to non-specific hydrolysis, (2) the absence of a defined endpoint of the incubation, (3) the non-linearity of the assay with respect to plasma concentration, (4) the temperature-dependent evolution of esterase activity during incubation, and (5) most importantly the loss of activity during storage of plasma samples. Cleavage of MUGB catalysed by the imidazole ring of histidine accounts for a significant portion of the activity in plasma.

Does a primary host defense abnormality involving monocytes-macrophages underlie the pathogenesis of lung disease in cystic fibrosis?

The primary cause of morbidity and mortality in cystic fibrosis (CF) patients is chronic pulmonary disease. Pulmonary disease in CF is characterized in part by: (a) obstruction of the bronchi and bronchioles by inspissated secretions (mucus is hypersecreted and may also be abnormal), (b) recurrent or persistent bacterial infections, and (c) a chronic inflammatory state. We propose herein that much of the pathophysiology of lung disease in CF stems from a genetically inherited metabolic defect in monocyte-macrophages (M-Mphi), and we review evidence which indicates that CF M-Mphi are innately metabolically abnormal. Once activated by various stimuli, CF M-Mphi become metabolically hyperactive and hypersecretory as evidenced by the production of excessive levels of a variety of mediators which could have definite roles in both the initiation of pulmonary obstruction and the accelerated development of a chronic inflammatory response in CF. Evidence is also reviewed which indicates that other CF M-Mphi functions crucial to the afferent and efferent phases of the immune response to bacterial infections in the lung may be adversely affected. Mechanisms proposed to explain the abnormal production of mediators by CF M-Mphi are discussed, and it is concluded that hyperproduction of mediators by CF M-Mphi and their metabolic hyperactivity probably result from a defect in autoregulation. The nature of the metabolic defect in CF M-Mphi indicates that CF should be classified as a "new" primary host defense abnormality or alternatively as a "new" primary immune deficiency disease.

Protease binding by alpha 2 macroglobulin in cystic fibrosis

The interaction of alpha 2 macroglobulin (alpha 2M) with exogenous proteases has been reported by others to be abnormal in cystic fibrosis (CF). We have re-examined these claims. Four parameters were considered:(1) the molar protease binding of alpha 2M; (2) the interaction of bovine cationic trypsin (BCT), complexed to alpha 2M, with low molecular mass substrate, benzoyl arginine ethyl ester (BAEE); (3) the stability of formed alpha 2 M-BCT complexes; and (4) the subunit structure of alpha 2M. We have found CF alpha 2M to be similar to control alpha 2M in every respect studied.

Cystic fibrosis ciliary dyskinesia substances and pulmonary disease. Effects of ciliary dyskinesia substances on neutrophil movement in vitro

Cultured mononuclear cells (MNC) from individuals homozygous or heterozygous for the defective gene causing the inherited disease cystic fibrosis (CF) synthesize three unusual "mediators" termed ciliary dyskinesia substances (CDS), which markedly affect tracheal mucociliary systems in vitro. MNC cultures from normal healthy controls do not accumulate any CDS, whereas MNC cultures from non-CF patients controls with pulmonary disease synthesized at least one CDS. The possible involvement of the CDS in pulmonary disease is being investigated. In this study, we sought to determine whether the CDS could be chemoattractants for polymorphonuclear neutrophils (PMN), since they have characteristics in common with known chemoattractants generated by alveolar macrophages. Our analyses of crude MNC culture supernates indicated that cultures from both CF genotypes accumulate significantly higher levels of PMN chemoattractants than do analogous cultures from normal healthy controls. CF homozygote MNC also generated more activity than MNC from patient controls with chronic pulmonary disease. Fractionation of MNC culture supernates by gel permeation chromatography and characterization of active fractions demonstrated six distinct PMN chemoattractants in cultures from CF genotypes; five were also present in patient control and four in normal healthy control cultures. The excessive chemoattractant activity in MNC cultures from CF genotypes and patient controls was due to several different substances produced by monocytes: (a) two components of 1,000-3,500 mol wt. (b) two fragments of C5, and (c) a fragment of C3. One C5 fragment had ciliary dyskinesia activity, the other did not. The C3 fragment chemoattractant also had ciliary dyskinesia activity and was not found in MNC cultures from patient controls. A third CDS, Which is CF-specific (5,000 mol wt), was neither chemotactic not chemokinetic and did not inhibit random PMN migration; however, fractions containing this CF-specific CDS completely inhibited PMN chemotaxis in response to three different chemoattractants. We conclude that all of the CDS can potentially play a role in the pathophysiology of lung disease, as judged by their effects on PMN movement in vitro.

Altered regulation of a proteinase mediated primary secretion processing system as the basic defect in cystic fibrosis

Depsite the high incidence of cystic fibrosis there is no clear cut direction to research into the basic defect responsible for this disorder. This is, at least in part, due to the exceptional amount of irreproducibility surrounding the disease. The defective ion reabsorption in CF sweat glands may be a prototype of a generalized failure to correctly process exocrine gland primary secretions. Such a physiological defect could account for many of the clinical symptoms of CF. It is hypothesised that one or more secreted proteinase(s) may mediate the events of secretion processing. A mutation in the structural gene for such a proteinase or a regulating anti-proteinase or some enzyme carrying out a functionally important post translational modification of the proteinase would then account for the disease.