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Biomedical subjects

J C Brouet

Publications and source records attributed to J C Brouet.

At least 109 records · Page 6Linked to original sources
PubMed1990

Alpha heavy chain disease of patient MAL: structure of the non-functional rearranged alpha gene translocated on chromosome 9.

Alpha heavy chain diseases (HCD) are lymphoproliferative disorders characterized by the production of truncated alpha immunoglobulin heavy chain without associated light chains, alpha HCD MAL is featured by multiple structural alterations of the alpha 1 productive gene and on original t(9;14)(p11;q32) translocation involving the other rearranged alpha 1 allele. We present here the structure of the der(9) chromosome. Sequence analysis provides evidence that the translocation occurred after local pairing of the two chromosomes mediated by an almost perfect nonameric sequence, followed by a staggered double-strand break of chromosome 14. This translocation occurred on a V(D)J rearranged locus; unexpectedly, there were a deletion of the 3' part of the VH gene, several insertions of non-immunoglobulin-related genes and multiple mutations, i.e. alterations reminiscent of those occurring on the HCD productive genes.

B-Lymphocytes↗
PubMed1990

Antinuclear antibodies directed to a 200-kilodalton polypeptide of the nuclear envelope in primary biliary cirrhosis. A clinical and immunological study of a series of 150 patients with primary biliary cirrhosis.

Antinuclear antibodies giving a perinuclear fluorescence and directed to a 200-kilodalton polypeptide of the nuclear envelope have been described in primary biliary cirrhosis. The purpose of this study, based on a series of 150 patients with primary biliary cirrhosis, was to ascertain the prevalence of these antibodies and to compare patients with and without these antibodies. Antinuclear antibodies giving a perinuclear fluorescence were demonstrated in 43 of the 150 patients (29%); antibodies directed to the 200-kilodalton polypeptide of the nuclear envelope were found in 40 of these 43 patients. Asthenia, arthralgia, associated extrahepatic diseases, Raynaud's phenomenon, and other antinuclear specificities were significantly less common, and titers of antimitochondrial antibodies were significantly lower in patients with antibodies directed to the 200-kilodalton polypeptide of the nuclear envelope than in patients without these antibodies. Clinical outcome, liver tests, and histological lesions did not significantly differ in patients with and without these antibodies.

Antibodies, Antinuclear↗
PubMed1990

Interleukin 6 dependence of spontaneous in vitro differentiation of B cells from patients with IgM gammapathy.

Blood B cells from eight patients with clonal lymphoid disorders characterized by monoclonal IgM secretion (four with malignant plasmacytic proliferation typical of Waldenström macroglobulinemia and four without overt lymphoid neoplasia) were found to spontaneously differentiate in vitro into plasma cells. In all instances, monoclonal plasma cells (8-45% of the cells) were generated from extensively purified B cells or T-cell-depleted peripheral blood mononuclear cells after a 7-day culture period, with a corresponding high rate of IgM secretion into the culture medium. This differentiation occurred in the absence of any cell proliferation process as measured by [3H]thymidine uptake at day 2 or 4. Normal B cells did not differentiate under the same experimental conditions. Detection of interleukin 6 (IL-6) bioactivity in all patients' B-cell culture supernatants as well as of IL-6 mRNA in freshly prepared, uncultured B cells in the two cases studied by in situ hybridization suggested that IL-6 secretion by B cells may play a role in this process. Moreover, in the four patients without overt lymphoid proliferation, B-cell differentiation was significantly inhibited (60-80%) in the presence of anti-IL-6 antibodies. In contrast, anti-IL-6 antibodies did not preclude the differentiation into plasma cells of B cells from the four patients with bona fide Waldenström macroglobulinemia. These results suggest a two-step pathogenesis for such human lymphoplasmacytic clonal proliferations, the initial stage being characterized by an IL-6-dependent autocrine differentiation pathway.

Antibodies, Monoclonal↗
PubMed1990

Reactivity of human monoclonal IgM with nerve glycosphingolipids.

We examined the reactivity of monoclonal IgM of sera from patients with neuropathy and monoclonal IgM, with or without antibody activity to myelin-associated glycoprotein (MAG), as well as sera from non-neurologic patients with Waldenström's macroglobulinaemia, with various nerve glycolipids extracts or with purified gangliosides. As expected from previous studies, all (five cases) anti-MAG IgM stained two glycolipids, the chemical characteristics of which corresponded to sulphated glucuronyl-paragloboside (SGPG) and sulphated glucuronyl-lactosaminyl-paragloboside (SGLPG). Five of 12 sera from patients with neuropathy whose IgM was devoid of anti-MAG reactivity stained nerve extracts greatly enriched (98%) with SGPG and SGLPG. Three of these five sera reacted with additional glycolipids and/or gangliosides. Two of 16 sera from patients with macroglobulinaemia without neuropathy reacted strongly with both SGPG and SGLPG. The latter finding as well as the detection of low titre of anti-sphingolipid antibodies in normal sera may cast a doubt on the pathogenetic significance of this antibody activity.

Antibodies, Monoclonal↗
PubMed1990

Characterization of human autoantibodies specific for lamin A.

We have characterized human autoimmune polyclonal antibodies reactive with lamin A, a 74 kDa peripheral protein of the nuclear envelope. Unlike other known antibodies to lamin A, the antibodies described here do not crossreact with the structurally related lamin C. These antibodies feature only chi light chains suggesting that their specificity is restricted to a limited number of epitopes. Based on the known amino acid sequence of human lamins A and C, the epitope(s) are most likely located in the 80 amino acid carboxyl tail of mature lamin A.

Antibody Specificity↗
PubMed1990

Peripheral polyneuropathies associated with monoclonal IgM. Antibody activity of monoclonal IgM and therapeutic implications.

Monoclonal IgM from patients with peripheral neuropathy react in nearly 80% of the cases with some components of myelin. The main target is myelin associated glycoprotein (50% of the cases); several types of glycolipids or gangliosides have been identified as the reactive antigen in the other cases. Anti-MAG IgM share little cross reactive idiotopes. Only primate antisera identified a combining site related public idiotope. In fact, these IgM use various light and heavy chains belonging to different variability subgroups. The preliminary results of an ungoing trial aimed to establish the benefit of plasmapheresis in these patients are discussed.

Adult↗
PubMed1989

Multiple mutations in the variable region of the kappa light chains of three monoclonal human IgM with anti-myelin-associated glycoprotein activity.

Human monoclonal IgM having an antibody activity directed to myelin-associated glycoprotein have distinctive features. Amino-terminal sequence of light and heavy chains from 6 IgM kappa that we have previously studied indicated that heavy chains belong to the VHIII subgroup, whereas light chains belong to 3 different subgroups of variability (V kappa I 2, V kappa II 1, and V kappa IV 3). We report here the complete sequence of the variable domain of 3 L chains: 2 V kappa IV and 1 V kappa II subgroups. Strikingly an unusually high degree of mutations clustered in the complementarity-determining regions (CDR) 1 and CDR 3 was found and the variable regions were joined to three different JK segments. Amino acid substitutions did not yield similar sequence in the CDRs suggesting that the kappa chains had no predominant role in the unique binding activity of these IgM or alternatively they are directed against different epitopes. Data are consistent with the previously reported lack of easily demonstrated public idiotopes common to anti-myelin-associated glycoprotein IgM. The pathogenesis of these IgM autoantibodies is most likely different from that of previously studied monoclonal rheumatoid factors or cold agglutinins where a genetic restriction of L or H chains or both has been observed.

Amino Acid Sequence↗
PubMed1989

The productive gene for alpha-H chain disease protein MAL is highly modified by insertion-deletion processes.

alpha-H chain diseases (HCD) is a human lymphoproliferative disorder, characterized by the production of truncated alpha-Ig H chains, without associated L chains. In this study, we have analysed the serum protein, the alpha-HCD mRNA and the rearranged alpha-HCD gene from the leukemic cells of a patient (MAL) with alpha-HCD. The abnormal MAL serum Ig consisted of short alpha 1-chains, lacking VH and CH1 domains (only CH2 and CH3 domains were present). The alpha-HCD mRNA (1.2 kb) was shorter than a normal alpha-mRNA (2 kb); the corresponding cDNA had sequences for the leader, a 84-bp sequence of unknown origin and the CH2 and CH3 exons. The establishment of the sequence of the productive alpha-HCD MAL allele revealed two major deletions; that of the VH region as well as that of the CH1 region. The JH region is altered by multiple mutations, small insertions and a duplication of the psi JH3 region. A large insert (INS1), of 360 bp (containing the 84 bp exon found in the cDNA), replaces the deleted VH region. INS1 is non-Ig related and apparently of nongenomic origin. A large second insert (509 bp), is located between the enhancer and the switch region. Insert2 contains repetitive non-Ig-related sequences and a small Ig-related sequence. All these alterations resulted in an abnormal mRNA, which comprises the leader, a 84-bp alien exon derived from INS1 and the CH2 and CH3 exons of the alpha 1-gene.

Amino Acid Sequence↗
PubMed1989

Expression of a public idiotype by human monoclonal IgM directed to myelin-associated glycoprotein and characterization of the variability subgroup of their heavy and light chains.

Most studies using rabbit or mouse antisera failed to detect CRI between human IgM directed to MAG. We show here that 9 of 10 such IgM express a public CRI as defined by a nonhuman primate antiserum. Shared idiotype is likely involved in (or close to) the combining site of those IgM since antiidiotypic serum inhibited the binding of IgM to MAG and reacted with IgM having different variable regions of light and heavy chains. Partial aminoterminal sequence of heavy and light chains showed that anti-MAG IgM use either lambda chains (one IgM) or kappa light chains (six IgM) of different variability subgroups (V kappa IV in three instances, V kappa I in two, and V kappa II in one), whereas heavy chains belong to the VHIII (six IgM) or to the VHII (1 IgM) subgroup. These features distinguish these IgM from other human monoclonal IgM with a defined antibody activity, such as rheumatoid factors or cold agglutinins.

Amino Acid Sequence↗
PubMed1989

Neutral endopeptidase 24.11 and angiotensin converting enzyme like activity in CALLA positive and CALLA negative lymphoid cells.

Taking advantage of the recently demonstrated identity of common acute lymphoblastic leukemia antigen (CALLA) and neutral endopeptidase EC.24.11 (NEP) the presence of this ectoenzyme on lymphoid cells has been reassessed using highly sensitive assays (cleavage of [3H]-D-Ala2-leucine-enkephalin and binding of the inhibitor [3H]HACBO-Gly. NEP activity was found not only on already classified CALLA + ve cells but also on numerous cells (including mature B and polyclonal T cells) previously considered as CALLA-ve. This suggests that CALLA/NEP is expressed all along the differentiation pathway in B and T cell lineage. Moreover substantial ACE-like activity was also detected in three tested cells, all of the pre-B phenotype. The availability of specific inhibitors for these enzymes should help clarify their role in cell-differentiation.

Animals↗
PubMed1989

Regulation by interleukin 2 of CD23 expression of leukemic and normal B cells: comparison with interleukin 4.

Recombinant interleukin (IL) 4 has been shown to be able to up-regulate low-affinity Fc receptor for IgE (Fc epsilon RII)-CD23 expression on B cells as well as on other human mononuclear cells. We demonstrate here that, in opposition with previous reports, recombinant IL2 also can up-regulate CD23 expression on B cells. This was first observed on CLL cells which represent a monoclonal proliferation of B cells arrested at an intermediate stage of activation. Cells of 5 out of 12 B-CLL studied display such an increase and all 5 proliferated, in vitro, directly in response to IL2. Similarly, upon triggering with anti-mu and IL2, normal tonsillar B lymphocytes also demonstrate an increase of CD23 expression but this was observed only on day 3. Interferon-gamma was able to inhibit this IL2-mediated up-regulation of CD23 on normal B cells but not on CLL-B cells; on those cells interferon-gamma was similarly unable to inhibit the IL4-mediated CD23 up-regulation. These results suggest that CD23 regulation is complex and related to the stage of activation and the cell type.

Antibodies, Monoclonal↗
PubMed1989

Genomic alterations in a case of alpha heavy chain disease leading to the generation of composite exons from the JH region.

Human alpha heavy chain disease (HCD) is characterized by the presence in patient's serum of a short Ig alpha chain devoid of light chains. We analyzed the serum protein, the alpha HCD mRNA and the productive rearranged H chain gene from the leukemic cells of a new case (YAO) of alpha HCD. The abnormal YAO alpha 1 Ig was devoid of VH and CH1 domains and started at the beginning of the hinge region. The alpha HCD mRNA was shorter than normal alpha mRNA and the cDNA prepared from YAO mRNA encoded a leader sequence, an insert of 70 nucleotides and the CH2 and CH3 exons. The origin of the inserted sequence was assessed by cloning and sequence analysis of the alpha 1 productive gene. It started with a leader exon, a leader-VH intron and the first 11 bp of a VH exon. Then the VH region was deleted and replaced by a 19-nucleotide sequence that turned out to correspond to the 3' part of a modified JH5 exon. It was followed by a 221-bp sequence homologous to the JH5-psi JH3 intron and by an inserted sequence of unknown origin. The 3' part of this insertion and the remnant of a JH6 exon delineated a third exon that was followed by a relatively conserved JH6-C alpha intron. These two composite exons were flanked by splicing sites and accounted for the 70-nucleotide insert of the cDNA. The genomic nucleotide sequence also revealed a large deletion in the switch CH1 region which eliminated normal splicing sites and resulted in splicing of the third exon directly to the CH2 exon.

Amino Acid Sequence↗
PubMed1989

Prevalence of monoclonal Ig with lambda light chains in chronic myelocytic leukaemia.

Light chains from seven of eight monoclonal Ig detected in the serum of patients with chronic myelocytic leukaemia (CML) were of the lambda isotype. Although the presence of monoclonal Ig in CML is distinctly unusual, this prevalence of lambda chains is unlikely to be a mere coincidence. All patients had otherwise typical clinical, chromosomal and molecular (bcr rearrangements) features of classical CML. The lambda locus appeared unaltered. Only two patients had an excess of dystrophic plasma cells suggestive of multiple myeloma.

Aged↗
PubMed1989

Effect of passive transfer of human anti-myelin-associated glycoprotein IgM in marmoset.

Adult and one week old marmosets were injected intravenously within a one month period or intraperitoneally within a 6 week period respectively, with monoclonal IgM having an anti-myelin associated glycoprotein antibody activity. No clinical or electrophysiological abnormalities could be detected in experimental animals. However, indirect immunofluorescence studies showed IgM deposition in close contact to myelin sheaths. Minor but distinct alterations of nerves were found in the adult: the enlargement of Schmidt-Lanterman incisures seen in electron microscopy could explain the decrease of the proportion of fibers of small diameter found by morphometry of semi-thin section, and the reduction of the mean internodal length in fibers of a given diameter seen in teased nerve fibers studies.

Animals↗
PubMed1989

Molecular analysis of a t(9;14)(p11;q32) translocation occurring in a case of human alpha heavy chain disease.

We performed the cloning and sequencing of the der(14) breakpoint of a new chromosomal translocation involving the 14q32 immunoglobulin locus. This t(9;14)(p11;q32) translocation was found in a case of malignant lymphoma occurring in human alpha heavy chain disease. A rearranged alpha 1 gene fragment was cloned and shown to contain chromosome 9 information by Southern blotting on sorted chromosomes and by in situ hybridization. Sequence analysis of the junction point region established that the breakage occurred 3' to the heavy chain joining region. In contrast to the data obtained in other translocations affecting 14q32 immunoglobulin locus, the recombination did not involve the immunoglobulin heavy chain locus specific recombination signals on chromosome 14, or homologous sequences on chromosome 9. In the present case, the existence of two almost perfect inverted repeats flanking the junction point suggests that the translocation originated from a local pairing of the two chromosomes 9 and 14. Chromosome 9 fragments sequenced in the vicinity of the breakpoint did not share significant homology with sequences listed in GenBank and EMBL data bases.

Base Sequence↗