Human leukocyte antigen class II associations with systemic sclerosis in South Africans.

Human leukocyte antigen class II typing, using polymerase chain reaction-sequence-specific primers, was performed in 52 Black South Africans with systemic sclerosis (SSc) and 112 controls. Increased frequencies of DR2 in the overall SSc group (OR = 2.4), DRB1*0301 in the limited cutaneous SSc (lcSSc) subset (OR = 9.0), and DQB1*0301/4 in the diffuse cutaneous SSc (dcSSc) subset (OR = 9.0) were observed. Pulmonary fibrosis was associated with DRB1*11 and anti-topoisomerase I antibodies were associated with DPB1*1301 and DRB1*15. Patients with anti-fibrillarin antibodies (AFAs) had increased the frequencies of DRB1*1101 allele group (OR = 16) and DQB1*0603/14 (OR = 13.6). These findings provide new serological and immunogenetic data on a previously unreported population. The association of AFAs with class II alleles merits further investigation.

MHC class II associations with autoantibody and T cell immune responses to the scleroderma autoantigen topoisomerase I.

Topoisomerase I (topo I) is a major autoantigen recognized by autoantibodies in about 30% of sera from patients with systemic sclerosis (SSc). Certain HLA-DRB1 and HLA-DQB1 alleles have been reported to be associated with autoantibody and T-cell responses to topo I suggesting a T-cell dependent process. We have examined the MHC class II allele associations with anti-topo I antibodies in 16 patients with SSc compared to 250 healthy controls. Furthermore, we have studied the T cell responses to a recombinant full-length topo I molecule purified from a baculovirus expression system in eight patients with SSc and eight controls (five healthy and three with autoimmune disease). HLA-DR5 was significantly increased in patients with anti-topo I antibodies (P< 0.02). Proliferative peripheral blood mononuclear cell (PBMC) responses to soluble topo I were present in nine of 16 individuals (four of eight with SSc and five of eight controls), including the three SSc patients with anti-topo I antibodies. Homozygosity for HLA DQB1:30:Y alleles was present in five of nine responders (P< 0.03) compared to none of the non-responders. Our findings support the notion that the MHC class II background influences the ability to generate an autoimmune response to intracellular autoantigens to which the immune system may not have been tolerized. Additional factors associated with the generation of autoantibodies appear to be more intimately associated with the development of SSc.

Antineutrophil cytoplasmic antibodies and HLA class II alleles in minocycline-induced lupus-like syndrome.

We report 14 patients with minocycline-induced lupus-like syndrome (four men, 10 women; mean age 27.8 years) who developed a lupus-like illness after chronic use of minocycline for acne (1-10 years, median 3.8). Clinical features resolved completely on drug withdrawal (mean follow-up 11 months) and reappeared in two patients who were rechallenged. Sera from all 14 patients contained antineutrophil cytoplasmic antibodies (ANCA) giving a perinuclear pattern on indirect immunofluorescence on ethanol-fixed human neutrophils (p-ANCA), whereas 14 control asymptomatic individuals taking minocycline for acne were ANCA-negative. Eleven of the 14 patients had elevated antimyeloperoxidase antibodies and 10 had antielastase antibodies on enzyme-linked immunosorbent assay, which diminished on extended follow-up, as did other serological abnormalities. Major histocompatibility complex class II typing demonstrated that all of the 13 patients tested were either HLA-DR4 (nine of 13) or HLA-DR2 (four of 13) positive, and all had an HLA-DQB1 allele encoding for tyrosine at position 30 of the first domain. Our findings suggest a model whereby the presence of p-ANCA may be a marker for the development of lupus-like symptoms in genetically susceptible individuals taking minocycline for acne.

Association of markers for TGFbeta3, TGFbeta2 and TIMP1 with systemic sclerosis.

OBJECTIVES: To investigate whether six microsatellite markers known to map closely to genes involved in fibrosis are associated with systemic sclerosis (SSc). METHODS: Markers mapping to TGFbeta1, TGFbeta2, TGFbeta3, PDGFB, TIMP1 and COL5A2 were genotyped and allele frequency distributions compared in 191 patients and 196 controls. As TIMP1 maps to the X chromosome, male and females were analysed separately. Markers associated with SSc were further investigated according to whether patients had limited (lcSSc) or diffuse (dcSSc) cutaneous fibrosis. RESULTS: Associations were found between SSc and markers for TGFbeta3 (chi(2)=17.3, df=8, P=0.02), TGFbeta2 (chi(2)=25.2, df=13, P=0.02) and TIMP1 (with male SSc, chi(2)=11.9, df=5, P=0.03), between lcSSc and the TGFss2 marker (chi(2)=25.6, df=13, P=0.02), and between dcSSc and TGFbeta3 marker (chi(2)=27.1, df=8, P=0.001). Between lcSSc and dcSSc patients, the allele frequency distribution differed only for the TGFbeta3 marker (chi(2)=16.5, df=6, P=0.01). CONCLUSION: These associations indicate a possible role for TGFbeta3, TGFbeta2 and TIMP1 in genetic susceptibility to SSc and for TGFbeta3 in determining the degree of cutaneous fibrosis.

Clinical and serological associations with anti-RNA polymerase antibodies in systemic sclerosis.

There are three classes of RNA polymerase enzyme (RNAPs I, II and III). In systemic sclerosis (SSc), three main groups of anti-RNAP sera have been characterized by radioimmunoprecipitation techniques: anti-RNAP I/III sera, anti-RNAP I/II/III sera, and a group precipitating both RNAP II and topoisomerase I (topo I). Some sera in this third group precipitate the phosphorylated (IIO) form of RNAP II in the absence of the unphosphorylated (IIA) form. Certain other antinuclear antibodies (ANA) have also been detected in anti-RNAP IIO/IIA/topo I and anti-RNAP IIO/topo I sera. In the present study of 155 SSc patients, clinical features of individuals from each of these antibody groups were assessed and compared with those of patients from other autoantibody-defined groups. The anti-RNAP I/II/III antibody specificity was closely associated with the presence of diffuse cutaneous SSc (dc-SSc) (77.8%; cf. remaining group, 12.4%; P < 0.001; relative risk (RR) 6.3). Patients with anti-RNAP I/III antibodies also had an increased incidence of dc-SSc, but this was not significant (42.9%; cf. remainder, 15.7%). Anti-RNAP+ patients had a significantly increased incidence of renal involvement (29.0%, cf. remainder, 11.3%; P < 0.05; RR 2.6), with 40% of anti-RNAP I/II/III patients having renal disease. Meanwhile, the presence of anti-centromere antibodies (ACA) was associated with limited cutaneous SSc (lc-SSc) (100.0%; cf. remainder, 75.3%; P < 0. 005), together with reduced incidences of both renal disease (2.4%, cf. remainder, 22.1%: P < 0.01) and pulmonary fibrosis (21.4%, cf. remainder, 52.3%; P < 0.005; RR 1.9). Anti-topo I antibodies were associated with the presence of pulmonary fibrosis (69.7%; cf. remainder, 32.6%; P < 0.001; RR 2.1). A majority of anti-topo I sera were from lc-SSc patients, regardless of whether anti-topo I antibodies occurred alone (75.0%) or together with anti-RNAP IIO + IIA antibodies (75.0%), and this was similar to the remainder (86. 5%; NS). However, when anti-topo I+ patients were compared with the ACA group, and then with all anti-RNAP I+ patients (37.5% lc-SSc), significant differences were found in the occurrence of dc- versus lc-SSc (P < 0.005 and P < 0.05, respectively). In conclusion, these results confirm that there are three main groups of SSc sera, each characterized by the presence of a mutually exclusive SSc-specific autoantibody (ACA, anti-topo I or anti-RNAP I), and distinguished by patterns of cutaneous involvement and specific clinical features. It appears that, in each of the three groups of SSc patients, distinct pathological processes are occurring, which are responsible for the characteristic symptoms, for the modification of particular autoantigens and, consequently, for the production of particular autoantibodies. Based on these data, together with our previous results, it is further hypothesized that anti-RNAP II antibodies may be produced in the context of two different immune response pathways.

The detection by enzyme linked immunosorbent assay of P30 and 19-OH prostaglandin F1/F2, in the presence of a range of possible contaminants.

The potential of specific human semen markers, P30 and 19-OH prostaglandin F1 alpha/F2 alpha (PG F), ELISAs were compared in a blind trial. The PG F assay was shown to be at least ten times more sensitive than the P30 technique although cross reactivity problems with spermicidal creams and other possible domestic contaminants were identified. A simple method for the removal of such contaminants using a phenyl boronate column (PBA) was evaluated in an extensive blind trial.

Anti-RNA polymerase antibodies in systemic sclerosis (SSc): association with anti-topoisomerase I antibodies and identification of autoreactive subunits of RNA polymerase II.

The prevalence of autoantibodies to the three RNA polymerase (RNAP) enzymes in the sera of 249 SSc patients was measured using the technique of immunoprecipitation of 35S-methionine-labelled K562 cell extracts. Forty-six anti-RNAP sera were detected (18.5%) and three main groups were identified: anti-RNAP I/III sera (10; 4.0%), anti-RNAP I/II/III sera (15; 6.0%), and sera precipitating the phosphorylated (IIO) form of RNAP II (18; 7.2%). All sera in the third group also precipitated topoisomerase I (topo I), and six of them also precipitated the unphosphorylated (IIA) form of RNAP II. Although RNAP II/topo I multienzyme complexes may occur in cell extracts, autoreactive epitopes were shown to be located on both enzymes by a combination of antigen depletion studies, and in vitro assays which demonstrated functional inhibition of topo I activity. Furthermore, immunoblotting experiments using affinity-purified extracts demonstrated that all sera with anti-RNAP II antibodies recognized the largest RNAP II subunit in its phosphorylated form (IIo; 240 kD), whereas the unphosphorylated subunit (IIa; 220 kD) was only recognized by sera which also precipitated RNAP IIA. Therefore at least two different sites on the largest subunit of RNAP II are recognized by SSc sera, and one of these sites is unique to the phosphorylated (IIO) form.