Early and aggressive treatment of rheumatoid arthritis patients affects the association of HLA class II antigens with progression of joint damage

OBJECTIVE

The presence of certain HLA class II antigens is strongly associated with the progression of joint destruction in rheumatoid arthritis (RA). Such antigens may be more effective than other class II antigens in inducing the formation of autoreactive T cells after presentation of (auto)antigens. We investigated whether early and aggressive treatment with disease-modifying antirheumatic drugs could modify this relationship.

METHODS

We analyzed data from 2 studies of patients with early RA treated according to different strategies. The first study consisted of 2 cohorts, one (n = 109; median disease duration before treatment 4 months) was treated according to the pyramid strategy (initial nonsteroidal antiinflammatory drugs, followed by chloroquine [CQ] or sulfasalazine [SSZ] when necessary), and the other (n = 97; median disease duration before treatment 2 weeks) was immediately treated with CQ or SSZ. The second study comprised 155 patients (median disease duration 4 months) from the Combinatietherapie Bij Reumatoide Artritis (COBRA) trial, in which patients were randomly assigned to combination treatment with step-down prednisolone, methotrexate (MTX), and SSZ (n = 76) or with SSZ alone (n = 79). Prednisolone and MTX dosages were tapered and stopped after 28 and 40 weeks, respectively. The extent of joint damage was measured by the modified Sharp method.

RESULTS

In the pyramid treatment cohort, the median increase in Sharp score after 2 years was 12 in patients positive for the shared epitope (SE) and 1 in SE- patients. In the immediate treatment cohort, the median increase was 3 in SE+ patients and 2 in SE- patients. In the SSZ group of the COBRA study, the median increase in Sharp score after 1 year was 11 in DR4+ patients and 3 in DR4- patients. In the combination treatment group, the median increase was 4 in DR4+ patients and 2 in DR4- patients. Significance was confirmed by multiple regression using log-transformed scores.

CONCLUSION

Early and aggressive antirheumatic drug treatment affects the association of HLA class II alleles with progression of joint damage in RA.

Molecular mimicry in type 1 diabetes: immune cross-reactivity between islet autoantigen and human cytomegalovirus but not Coxsackie virus

Type 1 diabetes is caused by a T cell-mediated autoimmune destruction of the pancreatic beta cells. Molecular mimicry between viral pathogens and beta cell protein has been a popular theory to explain loss of tolerance in type 1 diabetes. However, functional data in support of this hypothesis have been lacking, presumably because the homologies were defined on the basis of linear similarities in peptide sequences, which ignores the criteria of HLA versus T cell receptor contact residues in peptide epitopes required for T cell recognition. We applied a HLA-binding dedicated peptide microarray analysis using autoreactive T cell clones specific for the autoantigen GAD65 to determine the algorithm of T cell recognition by this given T cell clone. The subsequent database search identified a 100% fit with cytomegalovirus peptide, which was subsequently shown to be recognized by these clonal T cells. However, T cell clones reactive with linear homologies previously described as putative candidates for T cell cross-reactivity between GAD65 and Coxsackie virus peptide were unable to recognize the homologous counterparts.