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Biomedical subjects

Y Gorgi

Publications and source records attributed to Y Gorgi.

At least 37 records · Page 2Linked to original sources

[Lupus in children in Tunisia].

In this study, we have analyzed the clinical and serological features related to 16 Tunisian children in whom diagnosis of systemic lupus erythematosus was made before or at the age of 15. Renal involvement was found in 75% of cases and renal biopsies have mostly revealed severe histologic patterns. All of the patients who have been followed received corticosteroids and in some cases required additional cytotoxic drugs in order to control disease activity. Five children died in a context of a renal failure. This study of childhood lupus in Tunisia confirms that the clinical course of this disease in children is often aggressive.

Adolescent↗

Common idiotypes expressed on human, monoclonal, abnormal immunoglobulins and cryoglobulins with polyreactive autoantibody activities.

Several human monoclonal immunoglobulins with the same autoantibody activity have been shown to have cross-reactive idiotypes (CRI). In this study, using polyclonal anti-idiotypic antibodies, we found that 28% of human monoclonal immunoglobulins with polyreactive autoantibody activity from myeloma, Waldenström's macroglobulinaemia and cryoglobulinaemia patients shared common idiotype(s). Furthermore, the latter were expressed on human and murine natural MoAbs (respectively in 12% and 22% of the clones tested) and on human IgG preparations used for therapeutic intravenous injections (IVIg) and which contain natural antibodies. These findings suggest that monoclonal immunoglobulins could arise from the proliferation of a clone that normally produces a natural antibody. The existence of common idiotype(s) between monoclonal immunoglobulins and IVIg could be relevant to the improvement noted after treatment with IVIg in patients suffering from peripheral neuropathies associated with monoclonal gammopathy.

Animals↗

Autoantibodies and circulating immune complexes in sera from patients with hepatitis B virus-related chronic liver disease.

Sera from 56 patients with hepatitis B virus-related chronic liver disease (CLD) and 30 normal individuals as controls were examined by enzyme immunoassay (EIA) for the presence of autoantibodies directed against actin, tubulin, myosin, double-stranded (ds) DNA, polymerized human albumin, thyroglobulin, and trinitrophenyl coupled to bovine serum albumin (TNP-BSA). Patients with CLD had consistently elevated levels of IgG, IgA, and IgM antibodies directed against all the panel antigens. The percentage of patients with autoantibodies of the IgA class was particularly high: respectively, 88 and 78% of the patients had strikingly high levels of anti-actin and anti-TNP-BSA IgA autoantibodies. High amounts of IgA and IgG antibodies to polymerized albumin as well as IgG to thyroglobulin were also detected. Circulating immune complexes (CIC) were isolated from patients' sera and their autoantibody activities were tested on the same antigen panel. The autoantibodies thus detected were of the same class and possessed the same activities, although at higher values than those present in the homologous sera. These results indicate that, regardless of their origin, autoantibodies are present in high amounts in the sera of these patients. Moreover, autoantibodies participating in the formation of CIC might play a pathological role.

Actins↗

C4 polymorphism in multiplex families with insulin dependent diabetes in the Tunisian population: standard C4 typing methods and RFLP analysis.

The polymorphism of C4A and C4B genes was investigated in Tunisian patients with insulin dependent diabetes (IDDM) and compared to family members (sibs) and to healthy controls. Multiplex families were analysed. A significant increase in C4AQO (26.86% vs 6.90%) and C4BQO (40.29% vs 8.28%) phenotypes was noted in IDDM patients compared with controls. Using RFLP analysis, we confirmed the high frequency of C4 null alleles. We also observed that most of these alleles were genes deleted in IDDM patients (72.23% vs 20% for CA4QO and 74.07% vs 16.70% for C4BQO). A significant decrease in the C4B long (14.92% vs 67.12%) form of the gene was also demonstrated by RFLP analysis compared with controls. Two haplotypes were frequently associated with IDDM patients in whom the C4A and C4B were deleted genes.

Adolescent↗

[Characterization and evolution of blood cryoglobulin in visceral leishmaniasis].

The evolution of immunological parameters in mediterranean visceral leishmaniasis reveal a type III mixed cryoglobulin with rhumatoid factor activity and antileishmania antibodies. This cryoglobulin follows the clinical signs of the disease and disappear under treatment. The authors insist on the transitory character of this cryoglobulin which is in relation with polyclonal stimulation of the immune system by parasitical infection.

Adult↗

Delta infection in chronic HBs Ag carriers in Tunisia: high prevalence in chronic asymptomatic HBs Ag carriers and in HBs Ag positive cirrhosis.

The presence of hepatitis B virus DNA, delta antigen and anti-delta antibodies was examined in 159 Tunisian chronic HBs Ag carriers: 45 were asymptomatic and 114 suffered from cirrhosis. Serum hepatitis B virus DNA was detected in two (4.5%) asymptomatic HBs Ag carriers and in 11 (10%) HBs Ag positive cirrhosis patients. The prevalence of HDV infection determined by the presence of anti-delta was relatively high in asymptomatic HBs Ag carriers (33%) and in HBs Ag positive cirrhosis patients (21%). Active ongoing HDV infection, detected by serum HD Ag and anti-delta IgM, was shown in five patients with cirrhosis and active hepatitis B virus replication. We conclude that hepatitis delta virus may be endemic in Tunisia and does not always inhibit hepatitis B virus replication.

DNA, Viral↗

A new duplication C4B*1,12 at the C4B locus associated with BF*S07 in a Tunisian population.

Twenty-five Tunisian families were analyzed for their complement alleles in order to detect duplications at the C4 loci. In this population, the most characteristic duplications are C4A2, B1.12 or C4A1, B1,12 always associated with BFS07 and C2C. This previously undescribed C4B1,12 duplication was found in seven families, five times in association with HLA-A2, B50.

Alleles↗

C3, BF and C4 polymorphisms in Tunisians.

The C3, BF, C4A and C4B polymorphisms were studied in a Tunisian population sample. The allelic frequencies for C3 were S = 0.844 and F = 0.148, and for BF, S = 0.535, F = 0.331, SO7 = 0.075 and F1 = 0.041. The most frequent C4 alleles were A3 and B1 followed in a decreasing order by A2, B2 and the A and B null alleles. The results indicate that the Tunisian population is intermediate between the Caucasian and Arab populations with some trace admixture of African Blacks.

Complement C3↗

[Antibodies against extractable nuclear antigens. Clinico-biological correlations in 100 cases].

The clinical significance of antibodies directed against extractable nuclear antigens with currently well-known antigenic targets, is studied in 100 patients affected with various connective tissue inflammations. The anti-Sm is the most frequently encountered antibody in lupus disease and overlapping connective tissue inflammations with a lupus component while the anti-RNP is related to mixed inflammation of the connective tissue and the dry syndrome. These antibodies, without being specific markers for a given disease, represent an additional biological argument for a better nosological classification of connective tissue inflammations. The use of immuno-impression, a more sensitive technique than immunodiffusion, could provide a better understanding of the immune response during these diseases and specify the diagnostic and prognostic value of various auto-antibodies. Analysis by immuno-impression of 36 sera among the 100 with antibodies directed against extractable nuclear antigens has enabled us to compare the two techniques and study the different specificities of these antibodies.

Adult↗

[HLA, A, B, C, DR, C4, Bf in insulin-dependent diabetics in the Tunisian population].

There is no doubt that the autoimmune process in human disease depends on genetic factors. Varying associations were noticed between HLA DR and autoimmune disorders. The frequency of HLA-A-B and DR antigens as well as the Bf and C4 allotypes have been investigated in insulinodependant diabetes mellitus (IDDM) and compared to that of healthy controls in Tunisian population. An increase of A30, DR3, DR4, BfF1, C4AQ0 and C4BQ0 and decrease of B40, DR2, DR5 and DR6 were found in diabetes when compared to the value observation controls. The strongest association was noticed with HLA, DR3 and DR4. The prospective role of DR2 and DR5 antigens were also confirmed. Examination of HLA, Bf and C4 alleles. Two supratypes associated with IDDM have been observed among the Tunisian patients.

Adolescent↗

Enzyme immunoassay analysis of antibody specificities present in the circulating immune complexes of selected pathological sera.

Using immobilized anti-C3 antibody and an enzyme immunoassay, sera from 26 patients (eight with systemic lupus erythematosus (SLE), four with Hashimoto's thyroiditis, eight haemophiliacs and six with post-hepatitis cirrhosis) containing high levels of circulating immune complexes (IC) were selected. The IC were precipitated with 2.5% polyethylene glycol, washed, treated with acid buffer, neutralized and tested using an enzyme immunoassay in parallel with the original sera for antibody activity against a panel of antigens: human myosin and thyroglobulin, mouse actin and tubulin, calf thymus DNA and trinitrophenyl coupled to bovine serum albumin (TNP/BSA). It was found that all the isolated IC may contain IgG, IgA and IgM antibodies reacting with actin tubulin and TNP/BSA and also, depending upon the disease, antibodies reacting with some of the other antigens of the panel. By comparison to the antibodies present in the original sera, higher titers of antibodies were found in the isolated IC while some antibody specificities not detected in a given serum were occasionally noted in the isolated IC. The antibodies present in the IC seem to possess characteristics similar to those of polyreactive human natural autoantibodies. It is concluded that natural autoantibodies participate actively in the formation of IC found in pathological sera.

Actins↗

[Complete deficiency in the C2 fraction of complement associated with a glomerular nephropathy: apropos of 2 cases].

Two patients with non-systemic idiopathic glomerulonephritis were found to have a complete deficiency of C2, the second component of complement; the clinical course and serological abnormalities are reported in detail. An immunogenetic analysis of the patients of two families was carried out. It was demonstrated that the homozygous C2 deficiency was associated with homozygosity for HLA-A25-B18-DR2-BfS-C4A4-C4B2 haplotype.

Adult↗

HLA-A,B,C and DR antigens in a sample of the Tunisian population.

The HLA-A, B and DR phenotypes of 109 unrelated Tunisian individuals have been determined. The HLA-A and B antigen frequencies were compared with data reported for European Caucasoids and various Arab populations. Most similarities in antigen frequencies were seen between Tunisians and Kabyles from North Africa. A high frequency of HLA-A23 and HLA-Bw50 was observed in Tunisians and all Arab populations. A very close similarity in HLA-DR antigen frequencies exists between Tunisians and European Caucasoids. Linkage disequilibria between alleles of HLA loci were examined; many instances of previously reported antigen associations were seen in Tunisians, together with a number of associations which have not been described elsewhere. Aw34B8 and A2DRw14 are suggested as being common haplotypes in Tunisians.

Adult↗