Mycophenolate mofetil reduces myofibroblast infiltration and collagen III deposition in rat remnant kidney.

BACKGROUND: Myofibroblasts have been shown to play a pivotal role in the synthesis of extracellular matrix components in several animal models of renal fibrosis. The purpose of the present study was to investigate whether mycophenolate mofetil (MMF) reduces interstitial myofibroblast infiltration and collagen III deposition in 5/6 nephrectomized rats. METHODS: Forty-five Wistar rats underwent 5/6 renal ablation and received by daily oral gavage either vehicle (N = 20) or MMF (N = 25) during the 60 days following surgery. Groups of five treated and five untreated rats were killed at two, four, and eight weeks after subtotal nephrectomy. Four untreated and three treated rats were killed at week 12, one month after treatment withdrawal. At the time of sacrifice, proteinuria, plasma, and urine creatinine were determined. Immunohistochemistry was performed on renal tissue for alpha-smooth muscle actin (alpha-SMA), a cytoskeletal marker of myofibroblasts, for type III collagen, and for proliferating cell nuclear antigen (PCNA). Moreover, in order to study the in vitro effects of MMF on fibroblast proliferation, rat fibroblasts were cultured in the presence or absence of mycophenolic acid (MPA). RESULTS: At all periods studied, MMF treatment improved renal functional parameters and progressively decreased remnant kidney hypertrophy and glomerular volume increment. Proliferating cells in renal tubules, interstitium, and glomeruli, as well as interstitial myofibroblast infiltration and interstitial type III collagen deposition, were also significantly reduced by MMF treatment. In addition, MPA exhibited a dose-dependent inhibitory effect on in vitro proliferation of rat fibroblasts. CONCLUSION: Reduction of interstitial myofibroblast infiltration may be an important event by which MMF significantly prevents renal injury following subtotal renal ablation. Thus, our results suggest that MMF could be useful to limit the progression of chronic renal disease toward end-stage renal failure.

IgM and IgA rheumatoid factors in canine polyarthritis.

IgM and IgA rheumatoid factor (RF) were detected by ELISA using a purified dog IgG as antigen in normal controls (N = 84), dogs with unclassified polyarthritis (N = 95), dogs with rheumatoid arthritis (RA) (N = 22), dogs with systemic lupus erythematosus (SLE) (N = 35), dogs with leishmaniasis or heart worm disease (N = 20) and dogs with pyometra (N = 16). Frequency and titre of IgM and IgA RF are low and comparable (P < 0.05) in dogs with unclassified polyarthritis or RA: respectively 24.2% and 27.3% for IgM RF and 21.0% and 18.2% for IgA RF; the mean titre being respectively 0.781 +/- 0.581 and 0.649 +/- 0.365 for IgM RF, and 0.774 +/- 1.331 and 0.740 +/- 1.169 for IgA RF. The frequencies of IgM and IgA RF are a little higher in dogs with SLE (IgM RF: 37.1%, IgA RF: 25.7%) and higher in dogs with leishmaniasis or heart worm disease (45.0% and 30.0%), especially in dogs with pyometra (68.7% and 37.5%). So, although dogs can produce IgM and IgA RF, these auto-antibodies are uncommon in dogs with RA. Furthermore, when RF are present their titre is much lower than in human RA.

Connective tissue changes in rheumatic heart disease.

The connective matrix of 17 surgically excised mitral complexes from patients with clinical diagnosis of rheumatic carditis was evaluated by semi-quantitative histopathological, immunohistochemical and ultrastructural parameters. Different and concomitant patterns of loose and dense fibrosis were observed with variable constitution and organization of collagen I, III, IV, procollagen III, laminin, fibronectin and elastin. Loose fibrosis exhibited codistribution of all matrix components, Initial phase of fibrosis was characterized by deposition of all matrix components organized in a network pattern. In dense fibrosis a parallel disposition of type I collagen bundles predominated. In the denser (hyalin) fibrosis, the collagen exhibited abnormalities in fiber diameters and in fiber conformation (hyperfibers) and there was reduction or disappearance of other matrix components. The presence of these different kinds of connective matrix and the ultrastructural alterations in collagen fibers are associated to different stages of fibrosis organization and probably reflect changes in collagen susceptibility to degradation. These morphologic patterns may be related to the evolution (stability or reversibility) of rheumatic sequelae.

[Evaluation of a fast test for direct research on streptococcal group A from pharyngeal samples]. / Evaluation d'un test rapide pour la recherche directe du streptocoque du groupe A dans les prélèvements pharyngés.

Importance of streptococcal pharyngitis rapid diagnosis is increasing. 645 patients with pharyngoamygdalitis were tested. The correlation between bacteriologic culture and rapid test is 86%, the sensibility of the test is 68%, its specificity is 92%, while the predictive positive and negative values are 75% and 90%. These results show the interest of the rapid test for the diagnosis of streptococcal pharyngitis.

Complement C3 and C5 degradation products during hemodialysis treatment: study of an index of membrane bioincompatibility.

In 10 hemodialyses (HD) with cuprophan (CU) and 10 with polyacrylonitrile (PAN), signs of complement activation were investigated by following arterial and venous levels of C3a, C3d and C5a, in order to propose a marker of bioincompatibility. Despite large individual variabilities, significant increases of these molecules were detected at t 20 min, particularly with CU device in the artery and more marked in the vein except for C3d with PAN. During the later stage of HD, while C3a and C5a levels gradually declined, but remained significantly higher than t 0 in all the patients treated with CU, the C3d concentration reached a plateau suggesting a continuous complement activation throughout HD. HD using PAN membranes were associated with a lower C3a, C3d and C5a generation and fewer dialyses generating these products. In some dialyses the higher arterial level of these molecules suggests an extra-dialyzer complement activation especially with PAN membrane. Although C5a venous levels appeared to be the more significant index of complement activation, for clinical purposes we propose the C3d arterial measurement as a reliable, non-expensive and technically simple indicator of membrane intolerance.

Discrepancies between two procedures for ds-DNA antibody detection: Farr test and indirect immunofluorescence on Crithidia luciliae.

Of the 54,911 sera routinely tested for anti-double stranded-DNA antibodies (Ab), 2,297 gave a positive reaction with both indirect immunofluorescence (IIF) on Crithidia luciliae (CL) and the Farr test, or with only one of the two tests. Of the sera giving positive reactions, only 1,499 (65.3% of the positive sera) were positive with both reactions. Among the remaining 798 sera (34.7% of positive sera), 48.25% gave a positive reaction with the Farr test and 51.75% with the IIF reaction. Of the discrepant Farr test(+), IIF-CL(-) sera, slightly fewer than half corresponded to a false positive reaction of the Farr test due to the presence in the serum of proteins other than Ab which were able to bind to the labelled ds-DNA to form a complex precipitable by 50% saturated ammonium sulfate solution. Slightly more than half of the other Farr test(+) IIF-C'(-) sera corresponded to a defect in the IIF-CL reaction. Among the discrepant Farr test(-) IIF-CL(+) sera, 1/3 corresponded to false positive reactions IIF-CL and 2/3 of the remaining sera contained weakly avid anti-ds-DNA antibodies undetectable using the Farr test.

Influence of heavy metals on the resistance of mice toward infection.

Previous studies have shown that heavy metals may exert marked immunomodulatory effects, at least in rodents, despite some discrepancies. However, the mechanism of their influence on the immune system is still unclear. As host resistance assays against experimental infections are generally considered as the most relevant criteria when predicting the immunotoxicity of drugs and chemicals, the effects of lead acetate, nickel chloride and sodium selenite on the resistance toward experimental Klebsiella pneumoniae infection was investigated in mice, with particular emphasis on the interference of the time of toxic exposure with the infectious challenge. Interestingly, one single intraperitoneal dose of 24 mg/kg lead or 4 mg/kg nickel enhanced the resistance of mice against Klebsiella pneumoniae when administered 24 hours before the infectious challenge, whereas host resistance proved to be impaired when the same dose was injected 5 hours after the infectious challenge. A 3-day pretreatment with 8 or 12 mg/kg lead also enhanced the resistance of mice but decreased it with 0.5 or 1 mg/kg nickel. In all cases, sodium selenite increased the resistance of mice toward infection. As lead, nickel and selenium appear to exert complex and possibly opposite effects on antibody response and phagocytosis, it remains to establish which immunotoxic consequences if any, an acute or chronic exposure to these heavy metals is likely to have in man.

Streptococcal group A polysaccharide antibodies assayed by an ELISA determination of antibodies in rabbit hyperimmune sera; normal levels in man and comparison with levels in patients with rheumatic fever and with poststreptococcal glomerulonephritis.

An enzyme-linked immunosorbent assay (ELISA) was adapted to measure antibodies to streptococcal group A polysaccharide. The components of the reaction were studied, including the concentration of the polysaccharide antigen, the suppression of non-specific reactions, optimal conjugate binding conditions and the most suitable plates. The specificity of this test was documented by studies using immune sera and polysaccharide antigens of various groups of beta-hemolytic streptococci. In addition dynamics of the antibody response in animals as well as in man were investigated. The upper limit of normal level of this antibody in normal healthy persons was determined by this technique. We found that 80% of patients with rheumatic fever and acute glomerulonephritis showed an elevation of the group A polysaccharide antibody titer. Determination of this antibody response by the ELISA technique is clinically useful in evaluation patients with the nonsuppurative sequelae of group A streptococcal infections.

Effects of josamycin on polymorphonuclear leucocyte chemotaxis.

The effects of josamycin on the chemotactic response of blood polymorphonuclear leucocytes were studied. After oral administration of 2 g/day or 50 mg/kg/day for five days in man and rats respectively, polymorphonuclear chemotaxis was reduced by 20%. After in-vitro incubation with 10 mg/l josamycin chemotaxis was unaltered, whereas a 15% decrease was noted with 25 mg/l josamycin. These data suggest that josamycin is unlikely to severely impair chemotaxis in patients.

Effects of erythromycin, josamycin and spiramycin on rat polymorphonuclear leukocyte chemotaxis.

The effects of three macrolide antibiotics were studied on rat polymorphonuclear leukocyte chemotaxis. Rats were given 25 mg/kg twice a day of either erythromycin, josamycin or spiramycin by gastric intubation for 5 days. In all cases, chemotaxis was found to be impaired by 10-20% only. As macrolides are known to reach high intracellular concentrations within polymorphonuclear leukocytes, our results suggest that these antibiotics are unlikely to exert a deleterious influence on the chemotactic response of treated patients.

Binding capacity of sera from systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA) to C3c. Evaluation by enzyme linked immunosorbent assay (ELISA).

Immunoconglutinins (IKs) are autoantibodies directed against antigenic determinants on C3 complement component. An ELISA was performed to detect IKs in sera from 50 RA patients, 50 SLE patients and 50 normal subjects. Comparison showed significantly higher levels in patients than in normal subjects (p less than 0.001) and higher IKs levels in RA than in SLE (p less than 0.001). IKs were not related to others biological tests, except a statistically significant inverse correlation between IKs and circulating immune complexes levels detected by conglutinin binding assay in RA.

Hypersensitivity reactions to Althesin infusion: measurement of complement involvement.

Two cases of hypersensitivity reactions in the course of slow infusion of Althesin are reported. Serial examination of their complement system showed a marked activation of the alternate pathway which returned almost to normal within 24 hours.

Detection of immune complexes by their complement-dependent binding to bovine conglutinin: technical aspects of a solid-phase immunoenzyme microassay and its application to normal and pathological sera.

A micromethod for the solid-phase conglutinin binding assay (Con BA) for the detection of circulating immune complexes (CIC) is described, in which the use of microplates, glucose oxidase-coupled anti-human immunoglobulins and automatic OD recorder contributed to the speed and low cost of this reproducible and sensitive test. The Con BA values of a large population of healthy blood donors had a wide distribution which in our series of 189 appeared to be trimodal. The Con BA values clearly reflected the levels of the main Ig classes (M, G, and A). This was confirmed by follow up of 6 individuals with high initial Con BA values. For 4 of them, a parallel decrease in Con BA value and IgG concentration was observed. In the 2 others, the sustained high level of Con BA remained unexplained. Complement components and activity of these sera were within normal limits. Because of fluctuation in the aggregated human gamma-globulins (AHG) reference curve, expression of results was based upon the standard deviation of 6 normal sera. In view of the above results, these sera were selected from those with the lowest Con BA values. On the basis that Con BA and C1q BA may detect CIC differing in their ag/ab ratio, sera from rheumatoid arthritis and chronic active B hepatitis patients with or without conventional rheumatoid factors (RF) were analyzed by both Con BA and C1q BA. RF-containing sera, likely to contain CIC in antigen excess, contributed exclusively to the highest C1q BA and lowest Con BA values. In contrast C1q BA-Con BA+ sera were preferentially RF negative. It is proposed that the complexes thus detected may be of idiotype-anti-idiotype nature.

[Current aspects of chemotaxis of phagocytic cells]. / Aspects actuels de la chimiotaxie des cellules phagocytaires.

Phagocytic cells, the first host defence against microbial attack, are remarkably mobile; they can move very rapidly to the infectious or inflammatory site. They migrate toward a chemotactic factor: C5a, lymphokines, bacterial products, leukotriene B4, etc. The binding of the chemotactic factor to its specific receptor on the cell leads to an activation of the phagocytic cell: the electric potential of the membrane changes, ionic fluxes and free calcium rate increase, arachidonic acid metabolites are produced, cyclic nucleotides are activated. This produces a change in shape, a polarization of the cell and, after cytoskeleton reorganization, migration of the cell towards the chemotactic factor. A constitutional or acquired abnormality of one of these steps induces a defect of chemotaxis for the phagocytic cells and severe infections.

[Value of anti hemolysin and anti-gammahemolysin assays for the diagnosis of staphylococcal infections, particularly of osteoarthritis (author's transl)]. / Intérêt du dosage des anti-alphastaphylolysines et des anti-gammastaphylolysines seriques pour le diagnostic des staphylococcies, en particulier ostéo-articulaires. A propos de 574 sujets témoins et de 144 staphylococcies bactériologiquement confirmées, dont 76 localisations ostéo-articulaires.

The authors report the results of more than twelve years' personal research on the value of anti-alphahemolysin (AASTL) and antigammahemolysin (AGSTL) assays for the diagnosis of staphylococcal infections, and particularly of osteoarthritis. Among 574 controls, AASTL levels exceeded 2 IU in only 14 subjects (11 of these, levels were between 2 and 3 IU). Levels less than, or equal to, 2 IU were therefore considered normal. This is consistent with previously published data. In 144 staphylococcal infections, confirmed by bacteriology, an increase in AASTL was found in 95 of all cases (65.9%) and in 54 of the 76 osteoarthritis' (71%). Similarly, AGSTL titres, which were under 1/160 (upper normal limit) in 138 controls, were increased in 35 patients with unequivocal staphylococcal infections (61.4%), and in 25 of 36 patients with osteoarthritis (69.4%). These results show that AASTL assay is reliable and often abnormal. However, assay of both hemolysins yields even better results. This dual assay was performed in 57 patients with staphylococcal infection. One hemolysin at least was increased in 47 patients (82.4%). This represents additional positivity in 15.7% of patients when compared to AASTL assay alone, and in 21% when compared to AGSTL assay alone. The high level of positive results with dual assay is even more striking when only staphylococcal osteoarthritis is considered: one or both hemolysins were increased in 91.1% of these patients (31/34).

[Serological diagnosis of Staphylococcus aureus infections using anti-A beta telchoic acid antibodies assay (author's transl)]. / Diagnostic sérologique des infections à Staphylococcus aureus par dosage des anticorps anti-acide teichoïque A beta.

225 contol subjects, 12 hospitalized staphylococcus free (34 sera) and 16 S. aureus infected patients (79 sera) were tested for anti-A beta teichoic acid antibodies, using counter-immunoelectrophoresis. Anti-alpha and gamma haemolysins antibodies were dosed in parallel in 164 sera. Less than 5 per cent of control sera (3,11 per cent) have an antibody titre higher than 1/8; this titre is therefore selected as threshold level of positivity. Ten of the 12 hospitalized patients without staphylococcal infections are below this level. 31,6 per cent of staphylococcus infected patients have higher serum titers; only 3,7 per cent have no antibodies. In the others, a significant rise in titres is observed. There is no correlation between anti-alpha and gamma staphylolysin and anti-teichoic acid antibodies titres. The method suggested, both easy and rapid, could be used in association with anti-staphylolysin dosage for serological diagnosis of staphylococcal infections.