Biomedical subjects
K Lassoued
Publications and source records attributed to K Lassoued.
Expression of surrogate light chain receptors is restricted to a late stage in pre-B cell differentiation.
Surrogate light chain (psi LC) genes are transcriptionally active in progenitor B (pro-B) cells before immunoglobulin genes are rearranged. Current hypothetical models suggest that the psi LC proteins may couple with surrogate or conventional heavy chain proteins to form cell surface receptors that signal the progressive differentiation of pro-B, precursor B (pre-B), and immature B cells. Monoclonal antibodies were produced and used to examine the synthesis, expression, intermolecular interaction, and function of psi LC during B cell differentiation. The results indicate that, while psi LC production spans several developmental stages, cell surface expression is confined to a relatively late stage in normal pre-B cell differentiation, during which receptor cross-linkage does not impede cell growth or B cell differentiation.
Nucleotide sequence analysis of the VL and VH domains of five human IgM directed to lamin B. Evidence for an antigen-driven process in the generation of human autoantibodies to lamin B.
OBJECTIVE: To gain insight into the genetic origin of human antilamin autoantibodies, we determined the nucleotide sequence of the light and heavy chain variable region (VL and VH) domains of 5 IgM antibodies directed to lamin B. These antibodies represent a distinct subset of antinuclear antibodies, and their presence is associated with a particular lupus-like syndrome. METHODS: We derived and cloned lymphoblastoid cell lines from peripheral blood B cells of 3 patients, selected anti-lamin B-producing subclones, and sequenced the messenger RNA coding for Ig heavy and light chains. RESULTS: We isolated 2 subclones (1 IgM kappa, 1 IgM lambda) from one patient (FUR) and 2 subclones (both IgM lambda) from another (HER). In contrast, all 8 lines derived from B cells isolated from the third patient (BEN) synthesized identical anti-lamin B IgM kappa antibodies: All VL and VH domains from these 5 IgM were encoded by different VL or VH genes. DH regions were all different, and there was no restriction in the use of JL or JH segments. Analysis of the nucleotide sequence of the VL domains allowed the identification of the putative germinal gene in 3 instances (V kappa IV, Humkv325, and V lambda III.1); the overall ratios of replacement:silent mutations (R:S) were 6.5 and 1.2 in the complementarity-determining regions (CDRs) and framework regions (FRs), respectively. The 2 other lambda sequences belonged to the V lambda III family. With regard to VH domains, 3 of 5 derived from previously identified germline genes (VHIV 4.19, VHIV 4.22, and VHIII 9.1); the overall R:S ratio for these genes was 8 and 1.5 in CDRs and FRs, respectively. CONCLUSION: Taken together, these data provide evidence that the repertoire of human antilamin autoantibodies is not restricted and that the antigen (or another kind of selective pressure) plays a role in the generation of autoantibodies to lamin B. This hypothesis is in accordance with the reactivity of these antibodies to discrete epitopes of lamin B.
Characterization of two human monoclonal IgM antibodies that recognize nuclear lamins.
Using immunofluorescence and immunoblotting techniques, we have identified monoclonal IgM lambda from two patients that are specific for lamins A and C and lamin B, respectively. Lamins A, B, and C are peripheral membrane proteins of the nuclear envelope with structural similarities to cytoplasmic intermediate filament proteins. When studied by indirect immunofluorescence on rat tissues, the serum containing anti-lamin B IgM stained smooth and striated muscles in addition to nuclear envelopes. Lamin B antibodies affinity purified from this serum were able to label muscle cells, suggesting that lamin B shares an epitope(s) with an unidentified muscular component(s). Since in an enzyme-linked immunosorbent assay there was no reactivity with a panel of proteins which are frequent targets of "natural" antibodies, these monoclonal IgM appear to belong to the rare category of IgM that possess a restricted specificity.
Anti-lamin-B autoantibodies in a patient with cold urticaria.
Anti-lamin-B autoantibodies at a significant level had been found on two occasions in the serum of a 56-year-old woman who was suffering from an apparently idiopathic chronic cold urticaria. Anti-lamin autoantibodies can be detected in various autoimmune disorders including hepatitis, vasculitis and peripheral blood cytopenia. In our patient, there was no other clinical or biological abnormality. A chance association cannot be ruled out.
Human autoantibodies to lamin B receptor are also anti-idiotypic to certain anti-lamin B antibodies.
Autoantibodies reactive with nuclear envelope proteins are mainly detected in human sera from patients with liver diseases. Some of these antibodies are directed to lamin B, lamins A and C, or to the lamin B receptor (LBR). We show here that the latter one are anti-idiotypic to certain anti-lamin B antibodies. Using an enzyme-linked immunosorbent assay specific for lamins we found that serum M containing anti-LBR antibodies inhibited the binding to lamins of anti-lamin B autoantibodies from three of five sera tested. Similar results were obtained using patient's M purified IgG. The binding of monoclonal IgM, lambda anti-lamin B antibodies produced by a lymphoblastoid cell line derived from the patient's blood lymphocytes was also inhibited. Absorption of serum M with nuclei abolished the inhibitory activity. No inhibition was recorded with normal sera or sera containing other antinuclear specificities. Anti-LBR antibodies did not alter the binding to lamins of sera containing anti-lamins A and C antibodies. Altogether these findings demonstrate that anti-LBR antibodies are also combining site related anti-idiotypic antibodies (Ab2) to certain anti-lamin B antibodies, provide further evidence for discrete specificities among anti-lamin B antibodies and suggest that the occurrence of autoantibodies to nuclear envelope antigens may be under idiotypic regulation.
AIDS-associated Kaposi's sarcoma in female patients.
Kaposi's sarcoma (KS) is very unusual in Caucasian women with AIDS. We conducted a retrospective survey of 12 female AIDS patients with KS, including 11 Caucasian women. HIV infection was thought to have been acquired after sexual contact, intravenous drug use (nine cases) or blood transfusion (three cases). In these patients KS was often the first manifestation of AIDS and showed an aggressive course. The disease was associated with a severe immunodeficiency (CD4 T lymphocyte count less than 100 x 10(6)/l in 50% of cases) and a poor prognosis. In four patients, lesions first developed on areas of sexual contact, supporting the hypothesis that KS is a sexually transmitted disease.
Course of ankylosing spondylitis (AS) in patients with human immunodeficiency virus (HIV)
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[Bronchial complications of primary humoral immunodeficiency].
Primary humoral immunodeficiency is characterized by an abnormal immunoglobulin production. More than twelve forms are now known and a reviewed by the authors. The deficiency is responsible for bronchial infections which in the long term may result in bronchiectasis. It may also result in benign follicular hyperplasia. The specific treatment is substitutive and not devoid of hazards.
Treatment of the acquired immune deficiency syndrome-related Kaposi's sarcoma with bleomycin as a single agent.
A nonrandomized trial was conducted to assess the efficiency and toxicity of bleomycin as a single agent in treatment of non-life-threatening AIDS-related Kaposi's sarcoma (KS). Sixty patients were enrolled in this study. They all had a disseminated and progressive non-life-threatening AIDS-related KS associated with systemic symptoms and/or CD4 lymphocyte count less than 400/mm3. Thirty patients were treated with intramuscular bleomycin (5 mg/d for 3 days every 2 or 3 weeks) and 30 others with a slow continuous intravenous infusion of bleomycin (6 mg/m3/d for 4 days every 4 weeks). The mean duration of therapy was 5 months (range, 2 to 24 months). A partial response was observed in 29 patients (48.3%) and the disease was stabilized in 18 additional patients (30%). Bleomycin failed in 21.6% of patients. Therapy had to be discontinued in two patients because of side effects. Thus bleomycin as a single agent is a good alternative therapy for AIDS-related KS.
Identification and characterization of autoantibodies against the nuclear envelope lamin B receptor from patients with primary biliary cirrhosis.
We have identified autoantibodies from two patients with primary biliary cirrhosis (PBC) that recognize the nuclear envelope of mammalian cells on indirect immunofluorescence microscopy. These antibodies bind to a 58-kD integral membrane protein (p58) of the turkey erythrocyte nuclear envelope, which has been previously identified as a membrane receptor for lamin B (Worman, H. J., J. Yuan, G. Blobel, and S. D. Georgatos. 1988. Proc. Natl. Acad. Sci. USA. 85:8531). The antibodies also bind to a 61-kD integral membrane protein (p61) of the rat liver nuclear envelope. Affinity-purified antibodies eluted from turkey p58 bind to rat p61, showing that the two proteins share an epitope(s) and that p61 is likely the rat liver lamin B receptor. In human nuclear envelopes, the antigen recognized has an apparent molecular mass close to that of avian protein. These findings, along with the previous discovery of autoantibodies against an integral membrane glycoprotein (gp210) of the nuclear pore membrane in patients with PBC, suggest that antibodies against integral membrane proteins of the nuclear envelope are characteristic of a subset of patients with PBC.
Autoantibodies to lamins in rheumatoid arthritis.
The presence of autoantibodies reacting with lamins A and C was demonstrated in sera from 2 patients with rheumatoid arthritis (RA). One patient developed antilamin antibodies several years after being diagnosed as having RA; she was also found to have chronic active hepatitis. The second patient had severe nodular RA. We describe the other serologic findings in these 2 patients and discuss the relationships between antilamin antibodies and RA.
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.
Cutaneous manifestations associated with gamma heavy chain disease. Report of an unusual case and review of literature.
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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.
The 210-kD nuclear envelope polypeptide recognized by human autoantibodies in primary biliary cirrhosis is the major glycoprotein of the nuclear pore.
We have recently reported a new family of nuclear autoantibodies in a subset of patients with primary biliary cirrhosis. These antibodies bind to a nuclear envelope polypeptide(s) of approximately 200 kD, the exact identity of which was not established. In this study, we show that all of these autoantibodies are directed against a 210-kD integral membrane glycoprotein of the nuclear pore.
[Primary biliary cirrhosis: current modes of presentation. Clinical, biochemical, immunologic and histologic study of 206 patients seen from 1978 to 1988].
The aim of this study, based on a series of 206 patients (186 women and 20 men) with primary biliary cirrhosis seen from 1978 to 1988, was to assess the current modes of presentation of the disease. In approximately 30 percent of patients, primary biliary cirrhosis was recognized at an asymptomatic stage. Two thirds of these patients remained asymptomatic: they were older (mean age 57 years) and had less severe histological lesions than the patients who became symptomatic (mean age 45 years). The modes of presentation were not markedly different in the male and female patients of our series. The prevalence of cholelithiasis seemed to be particularly high (more than 20 percent in our patients). Complications of portal hypertension (bleeding esophageal varices or ascites) were the initial manifestations of primary biliary cirrhosis in 8 percent of our symptomatic patients. Alkaline phosphatase level was normal or only slightly increased in 15 percent of our patients: a normal level or a slight increase in alkaline phosphatases is not an argument against the diagnosis of primary biliary cirrhosis. Antinuclear antibodies with perinuclear fluorescence were demonstrated in 26 percent of our patients; in most of these patients, an antibody to a 200 kD protein of the nuclear envelope was present; in patients with this antibody, asthenia, arthralgias and associated extrahepatic diseases were less common and the titers of antibodies to mitochondria were lower than in the patients without this antibody.