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Biomedical subjects

M Kazatchkine

Publications and source records attributed to M Kazatchkine.

At least 19 recordsLinked to original sources
PubMed2006

IgM-enriched human intravenous immunoglobulin suppresses T lymphocyte functions in vitro and delays the activation of T lymphocytes in hu-SCID mice.

Previous studies of an experimental human immunoglobulin preparation for intravenous use, containing normal pooled IgM (IVIgM), have shown its beneficial therapeutic effect in experimental autoimmune diseases. The mechanisms of its immunomodulatory activity remain however, poorly understood. In the experiments reported here, IVIgM inhibited the proliferation of various autonomously growing human lymphoid cell lines in vitro, as well as of MLR- and of PHA-stimulated human T-lymphocytes. These effects of IVIgM were observed at non-apoptotic concentrations and were stronger on a molar basis than those of normal pooled IgG for intravenous use (IVIg). Both preparations, when administered to SCID mice, repopulated with human peripheral blood mononuclear cells, delayed the expression of the early activation marker CD69 on both human CD4+ and CD8+ T-lymphocytes, activated by the mouse antigenic environment. The data obtained show that normal pooled human IgM exerts a powerful antiproliferative effect on T-cells that is qualitatively similar but quantitatively superior to that of therapeutic IVIg. Our results suggest that infusions with IVIgM might have a significant beneficial immunomodulating activity in patients with selected autoimmune diseases.

Animals↗
PubMed2002

Lupus-specific kidney deposits of HSP90 are associated with altered IgG idiotypic interactions of anti-HSP90 autoantibodies.

Previous studies have shown that autoantibodies to heat shock protein 90 (HSP90) are elevated in a significant proportion of patients with systemic lupus erythematosus (SLE) who are more likely to have renal disease and a low C3 level. Using samples from 24 patients, we searched for glomerular deposits of HSP90 in renal biopsy specimens from seven patients with lupus nephritis and 17 cases of glomerulonephritis from patients without SLE. Positive glomerular immunofluorescent staining for HSP90 was observed in six of seven cases of SLE and positive tubular staining in two of seven SLE patients. The staining for HSP90 was granular in nature and was located in subepithelial, subendothelial and mesangial areas. None of the non-SLE renal biopsies revealed positive staining for HSP90 deposition. Further we showed the presence of anti-HSP90 IgG autoantibodies in IgG from sera of patients with SLE as well as in normal human IgG (IVIg). In normal IgG this autoreactivity could be adsorbed almost completely on F(ab')2 fragments from the same IgG preparation, coupled to Sepharose and could be inhibited by the effluent obtained after subjecting normal IgG to HSP90 affinity column. These findings indicate that anti-HSP90 natural autoantibodies are blocked by idiotypic interactions within the IgG repertoire. Unlike natural autoantibodies, anti-HSP90 IgG from SLE patients' sera were only moderately adsorbed on F(ab')2 fragments of normal IgG. These results demonstrate that immunopathogenesis of lupus nephritis is associated with HSP90 (as an autoantigen) and that the pathology is associated with altered idiotypic regulation of the anti-HSP90 IgG autoantibodies.

Animals↗
PubMed2002

[Efficacy of intravenous immunoglobulin in the treatment of Birdshot retinochoroiditis].

AIM: To evaluate the efficacy of intravenous immunoglobulin (IVIg) in the treatment of Birdshot retinochoroiditis. PATIENTS AND METHODS: Eighteen patients were followed-up prospectively in a total number of 37 patients recorded. Inclusion criteria were birdshot retinochoroiditis (BRC) according to the criteria defined by Ryan et al., and a decrease in visual acuity (VA). Efficacy was assessed by measurements of visual acuity and a decrease in inflammation and macular edema on fluorescein angiograms. RESULTS: Sex ratio=1, mean age was 51 (range 29 to 72 years), HLA A29 was positive in 100% of the patients. VA at baseline was 0.6+/-2.4 (range 0.25 to 0.9). Angiography showed retinal vasculitis in 32 patients (86.48%) and cystoid macular edema in 16 patients (43.24%). IVIg was administered at a dosage of 0.4g/kg/d for 4 days then 0.6g/kg/d for 2 days every 4 weeks. Follow-up lasted a mean of 2.7+/-2.0 years (range, 4 months to 5.6 years). Visual acuity of 35 out of 66 eyes (53%) increased by 2.6+/-1.5 (range 1 to 5). In 19 eyes out of 66 (29%), VA remained stable and in 12 eyes out of 66 (18%), VA decreased by -1.8+/-0.8 (ranges-4 to -1). Inflammation on fluorescein angiography improved in 17 patients (81%) and cystoid macular edema decreased in 65% of the cases. Side effects were rare. Treatment was discontinued for side effects in only 3 patients. DISCUSSION: BRC is a chronique disease threatening vision. Treatments including systemic corticosteroids and cyclosporin A may result in severe long-term side effects. IVIg is well tolerated and may be therapeutic alternative for the treatment of BRC.

Adult↗
PubMed2001

Normal IgG protects against acute graft-versus-host disease by targeting CD4(+)CD134(+) donor alloreactive T cells.

Intravenous immunoglobulin (IVIg) was shown to decrease the severity of acute graft-versus-host disease (aGVHD) in recipients of allogeneic bone marrow transplants. To investigate the mechanisms involved in the protective effect of IVIg, we have used the parent-into-F1 model in which parental lymphocytes are transferred into semi-syngeneic non-irradiated F1 rats. Here we report that IVIg, as well as F(ab')(2) fragments of IVIg, protected (Lewis x Brown-Norway) F1 rats against aGVHD induced by a single injection of Lewis lymphocytes. IVIg was given as five consecutive daily injections, starting on the day preceding that of the transfer of Lewis cells. Protection was associated with a decreased ability of lymphocytes to spontaneously proliferate and to produce NO and IFN-gamma, in the absence of an increased production of IL-10. We further demonstrate that protection was associated with a decrease in CD4(+) T cells bearing the activation marker CD134 in vivo, and with an enhanced apoptosis of activated CD4(+) T cells by IVIg, in vitro. Our observations suggest that the prevention of aGVHD by IVIg in this model is mediated by the induction of apoptosis of activated alloreactive CD4(+)CD134(+) donor T cells. The results further emphasize the role of normal immunoglobulin in modulating alloantigen immune responsiveness.

Acute Disease↗
PubMed2000

[Immunomodulatory effects of intravenous immunoglobulins].

Intravenous immunoglobulin (IVIg) has been used for many years in the treatment of primary and secondary antibody deficiencies. IVIg was first demonstrated to be effective in auto-immune desorders twenty years ago in the treatment of idiopathic thrombocytopenic purpura. The beneficial effect of IVIg has since been established in the Guillain-Barré syndrome, chronic inflammatory demenilating polyneuropathy, myasthenia gravis, dermatomyositis, Kawasaki syndrome and graft versus host disease. The beneficial effect of IVIg has been suggested in a large number of other auto-immune and systemic inflammatory conditions. The mode of action of IVIg is complex, involving Fc receptor blockade, interference with complement activation and the cytokine network, provision of anti-idiotypic antibodies and modulation of T and B cell activation and differentiation. Such a broad range of activities reflects the function of normal circulating immunoglobulins in maintaining tolerance to self in healthy individuals.

Adjuvants, Immunologic↗
PubMed1998

The sequential occurrence of pol 215 and pol 41 zidovudine resistance mutations is associated in an additive fashion with low CD4 cell counts and high plasma and cellular HIV viral load.

We report on a cross-sectional study of virological and immunological surrogate markers of HIV infection in 115 patients for whom a determination of the pol 215 and pol 41 zidovudine (ZDV) resistance mutations had been described between January 1995 and February 1996. The patients received ZDV alone or a combination of ZDV and zalcitabine or didanosine. A total of 55, 15 and 45 patients exhibited a wild (W), a mixed (MIX) or a mutant (M) genotype at codon pol 215, respectively; 85, 10 and 20 patients exhibited a W, a MIX or a M genotype at codon pol 41, respectively. Patients exhibiting the pol 215 M genotype had lower CD4 cells, higher plasma viral load and higher proviral burden than patients exhibiting the pol 215 W genotype. Patients who had variants exhibiting both pol 215 M and pol 41 M or MIX genotypes had significantly worsened surrogate marker values than patients having variants only carrying the pol 215 M genotype. These observations demonstrate that the two mutations additively associate with pejorative surrogate markers.

Adult↗
PubMed1997

Combined heterozygous deficiency of the classical complement pathway proteins C2 and C4.

Genetic deficiencies of components of the classical pathway of complement activation are associated with an increased risk for the development of autoimmune and immune complex-mediated diseases. In the present study we report on the molecular and clinical features associated with combined heterozygous C4 and C2 deficiency in 15 individuals investigated within six families. Approximately 30% of the individuals manifested SLE or another autoimmune condition. Heterozygous C2 deficiency was related to a 28-bp deletion in the C2 gene (C2 deficiency type I), in most cases within the HLA-A25 B18 C2Q0 BfS C4A4B2 DR2 haplotype. Among 13 partial C4-deficient haplotypes transmitted, 8 carried C4A*Q0 alleles and 5 C4B*Q0 alleles. In seven cases the C4A*Q0 alleles were associated with a deletion of the C4A/CYP21P genes within the HLA-B8 C2C BfS C4AQ0B1 DR3 haplotype. In three cases, the C4B*Q0 allele was associated with a deletion of the C4B/CYP21P genes within the HLA-B18 C2C BfF1 C4A3BQ0 DR3 haplotype. In the other cases, C4A*Q0 or C4B*Q0 was dependent on as yet uncharacterized defects in the C4 gene or in C4 gene expression. In view of the relatively high frequency of heterozygous C4 deficiency in the normal Caucasian population, the expected frequency of the combined deficiency should approximate 0.001.

Adult↗
PubMed1997

Dilution assessment of cervicovaginal secretions collected by vaginal washing to evaluate mucosal shedding of free human immunodeficiency virus.

A 10 mM concentration of lithium does not interfere with reverse transcription (RT) or PCR. Sampling of cervicovaginal fluid by vaginal washing, with lithium (10 mM) in the washing buffer as a marker of dilution, may be utilized to accurately determine in HIV-infected women, by quantitative RT-PCR, the genital shedding of acellular HIV RNA at the level of the mucosa itself.

Cervix Mucus↗
PubMed1997

Modulation of autoimmune responses by intravenous immunoglobulin (IVIg).

Significant progress has been made in understanding the mechanisms by which intravenous immunoglobulins (IVIg) exert immunomodulatory effects in the treatment of autoimmune diseases. A unique property of immunoglobulins is the diversity of variable (V) regions. The evidence discussed in this communication supports our notion that the diversity of V regions in IVIg preparations is a determining factor for the anti-inflammatory substitutive and immunomodulatory functions of IVIg therapy. We have demonstrated the presence in IVIg, of anti-idiotypic antibodies directed against various autoantibodies. The ability of IVIg to interact through V regions with complementary V regions of antibodies and antigen receptors as well as with relevant soluble and surface molecules provides the basis for inducing the selection of immune repertoires. The study of the mechanisms by which IVIg mediates selection of autoreactive repertoires is essential for our understanding of the mechanisms underlying the emergence of pathological autoimmunity and of the physiological role of natural antibodies in the establishment and maintenance of tolerance to self and homeostasis of autoreactivity in healthy individuals.

Animals↗
PubMed1997

Effects of non-steroidal antiallergic eyedrops on the complement-mediated histamine release from human cells.

Leukocytes from ten allergic patients (five allergic to dust-mites and five allergic to pollen) were treated with N-acetyl aspartyl glutamic acid (NAAGA) 4.9%, disodium cromoglycate (DSCG) 2%, lodoxamide (LODO) 1%, and levocabastine (LEVO) 0.5% (concentrations representing the pharmaceutical eyedrop preparations) for 20 minutes. Degranulation was then induced with Complement (rHu5Ca). Histamine was measured in the supernatant with ELISA. LODO and LEVO were inactive in blocking histamine released from human cells, and paradoxical unexpected effects were found with these two agents. They both induced significant histamine release in almost 100% of the samples. DSCG was able to block histamine release in seven patients out of nine (ranging between 5 and 34%). NAAGA was the most active agent on human cells and was able to block basophil degranulation in nine patients out of nine (inhibition ranging between 4 and 66% of total histamine pool).

Allergens↗
PubMed1997

[Lactic acidosis and hepatic mitochondrial changes during a treatment with zidovudine].

Adverse effects of zidovudine, which mainly result in myopathies and hematological disorders, could be due to multitissular mitochondrial toxicity of the drug. During zidovudine treatment, most cases of lactic acidosis have been attributed to mitochondrial myopathy. We report a case of hepatocellular failure with lactic acidosis in a 33 year-old patient with the human immunodeficiency virus infection and treated with zidovudine for 8 months. Liver biopsy showed massive macrovacuolar steatosis and ultrastructural mitochondrial abnormalities similar to those previously described in the skeletal muscle. This is the second reported case of lactic acidosis and hepatocellular failure which is probably related to hepatic mitochondrial dysfunction caused by zidovudine.

Acidosis, Lactic↗