Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twelve of 44 black American patients with systemic lupus erythematosus (SLE) (27%) studied during periods of disease activity had increased levels of IgG antibodies against cardiolipin (IgG aCL). IgG aCL occurred almost exclusively in patients who had a partial genetic deficiency of C4A or C4B. Eleven of 29 patients (38%) with a C4A or C4B deficiency allele had IgG aCL, compared with 1/15 patients (7%) who did not have C4A or C4B deficiency allele (p = 0.04). During periods when SLE was less active clinically, IgG aCL levels returned to normal in 10/12 patients. Active SLE, rather than null alleles, appeared to be associated with low C4 levels in patients with IgG aCL.
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PMID:Cardiolipin antibodies and null alleles of C4 in black Americans with systemic lupus erythematosus. 326 59

We report 3 black American patients with systemic lupus erythematosus (SLE) in whom C4B was completely deficient in plasma. They all exhibited antibody against the nucleoprotein antigen SSA (Ro), as well as cutaneous involvement, features that have been previously associated with complement deficiency states. IgG antibody against cardiolipin was also present in 2 patients, in association with a biologic false positive test for syphilis in one patient, and with thrombocytopenia in another. This is the first description of the clinical presentation of complete C4B deficiency in blacks with SLE.
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PMID:Complete C4B deficiency in black Americans with systemic lupus erythematosus. 326 61

The distribution of HLA-A, B, and DR alleles has been studied in 100 Chinese patients with systemic lupus erythematosus and in 100 healthy Chinese controls. Complement components factor B, C4A and C4B were studied in 72 patients and 61 controls. There was no significant difference between patients and controls in the distribution of HLA-A, HLA-B, factor B and C4B alleles, but there was a significant excess of HLA-DR2 and C4A null in the patients. An unusual variant of C4B was found in 6 patients and 1 control. The possible role of haplotypes is considered in interpreting these results and relating them to previous findings in Chinese.
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PMID:Strong association between the major histocompatibility complex and systemic lupus erythematosus in southern Chinese. 343 19

The complement components C4A, C4B, and factor B, and the HLA-A, B, C, DR, DQ, and DRw antigens were analyzed in 103 patients (66 Caucasian, 37 black) with systemic lupus erythematosus (SLE) and 98 control subjects (63 Caucasian, 35 black). Only the C4A null (silent) allele was significantly increased in SLE (0.254 versus 0.095 in Caucasians, p = 0.033; 0.200 versus 0.071 in blacks, p = 0.046). The absence of any detectable C4A gene products (homozygous C4A null or C4A*Q0,Q0) was found in 11.1 percent of Caucasian patients but in no control subjects (p = 0.006 with relative risk of 16.86). HLA-DR2 was significantly associated with Caucasian SLE (R2 = 0.63, p less than 0.0012). Multivariate analysis demonstrated that the HLA-DR2 antigen and C4A null allele contributed independently to the risk of SLE (relative risk 3.0 and 3.2, respectively); when HLA-DR2 and the homozygous C4A null phenotype were present together, the relative risk of SLE was 24.9. Both HLA-B8 and HLA-DR3 were increased in SLE, but these antigens are in linkage disequilibrium with the C4A null allele; the presence of HLA-B8 or DR3 did not contribute further to the risk of SLE. It is concluded that the HLA-DR2 antigen and the C4A null allele are independent and additive risk factors for development of SLE.
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PMID:Relationship between C4 null genes, HLA-D region antigens, and genetic susceptibility to systemic lupus erythematosus in Caucasian and black Americans. 346 13

A patient who presented with urticarial vasculitis, recurrent angio-oedema and gastro-intestinal symptoms in association with a 'lupus-like' disorder is documented. Other 'auto-immune' phenomena such as Sjogren's-like syndrome and polyarthritis were present in association with antibodies to RNP, low C4 and a null allele was demonstrated at the C4B locus. Response to varied therapies was poor and unsustained.
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PMID:Hypocomplementaemic urticarial vasculitis, angio-oedema and 'lupus-like' disease: association with C4B null allele. 349 4

The reported associations between HLA antigen DR3 and null (QO) alleles at the C4A and C4B loci and systemic lupus erythematosus are here analysed. The empirical logistic method has been applied to a body of data which included the relevant genotypes. The analysis suggests that the association with null alleles at the C4 loci is primary and the DR3 association is likely to be secondary to this. This may give information as to the location of the HLA-linked disease susceptibility gene.
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PMID:The association of HLA-linked genes with systemic lupus erythematosus. 350 Dec 70

A high frequency of serum complement component C4A deficiency may explain the higher prevalence and greater severity of systemic lupus erythematosus reported in Australian Aborigines. Inherited deficiencies of serum complement components C4A, C4B, and C2 were examined in two Australian Aboriginal populations from Darwin and Alice Springs and compared with the prevalence of complement deficiencies in white Australian blood donors. The frequency of C4A deficiency alleles was 29% in Darwin Aborigines compared with 12% in Alice Springs and 17% in Canberra blood donors. Partial C4B deficiency was also higher in Darwin Aborigines than in the other populations. Inherited deficiency of serum complement component C2 was not observed.
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PMID:A high frequency of inherited deficiency of complement component C4 in Darwin Aborigines. 350 12

Systemic lupus erythematosus (SLE) has shown associations with the major histocompatibility complex (MHC) class II DR antigens and class III complement components C2 and C4 in previous studies. The primary susceptibility locus has been difficult to identify, however, on account of linkage disequilibrium within the MHC. We have studied C4A and C4B distributions in 63 Caucasoid, 75 Chinese and 51 Japanese SLE patients. All three populations showed a statistically significant increase in C4A*Q0 (null) alleles when compared with 323 ethnically matched controls. We conclude that complete or partial deficiency of C4A is a genetic determinant of SLE common to these three ethnically distinct populations.
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PMID:Deficiency of C4A is a genetic determinant of systemic lupus erythematosus in three ethnic groups. 350 48

Long-term treatment with hydralazine is sometimes associated with deposition of immune complexes and development of systemic lupus erythematosus (SLE) as an adverse side-effect. Hydralazine inhibits the covalent binding reaction of the complement protein C4. We show that when hydralazine inhibits C4, it becomes covalently bound to the polypeptide chain containing the active site thiol ester. C4 is encoded at 2 adjacent polymorphic loci, C4A and C4B, within the major histocompatibility complex. We show that hydralazine binds more efficiently to the C4A than to the C4B gene product and suggest that C4 type may predispose patients to hydralazine-induced SLE.
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PMID:Hydralazine binds covalently to complement component C4. Different reactivity of C4A and C4B gene products. 387 56

Eight families (121 individuals) with two or more members affected with systemic lupus erythematosus (SLE) were analyzed for histocompatibility antigens (HLA-A, B, C, DR, MT, and MB) and complement antigens (C4A, C4B, and BF). These data were correlated with serological markers (antinuclear antibodies, single- and double-stranded anti-DNA, anti-SM, anti-nRNP, anti-Ro [SS-A], anti-La [SS-B], and biological false-positive tests for syphilis and clinical features. Fifteen members had SLE, and 19 had other immune diseases (subacute cutaneous lupus erythematosus, discoid lupus erythematosus, hypothyroidism, insulin-dependent diabetes mellitus, primary Sjogren's syndrome, immune thrombocytopenic purpura, rheumatoid arthritis, and multiple sclerosis). Twenty-three healthy relatives (seroreactors) had significant titers of circulating antibodies, as did 2 of 17 spouses. There was an increased frequency of null C4 alleles in those individuals with SLE (60%) and healthy relatives (50%) as compared with spouses (24%). Multivariate analysis showed a significant association between SLE and female sex (P =.006), whereas there was no significant association revealed between female sex and other immune diseases. Patients with SLE also had a higher frequency of either C4A or C4B null alleles (P = .01) than those with immune diseases. The C4A homozygous null phenotype was more common in SLE patients than in seroreactors (P = .02). There was a higher frequency of HLA-DR2 and DR3 in individuals with SLE than in those with immune disease (P = .08), seroreactors (P = .02) and normal relatives (P = .002). One totally C4-deficient patient with SLE was identified. These families demonstrate an important association between SLE and the C4 null allele and the HLA-DR2 and DR3. These risk factors, however, cannot account for the development of disease in all individuals.
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PMID:Null alleles of the fourth component of complement and HLA haplotypes in familial systemic lupus erythematosus. 387 10


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