The contribution of circulating anti‐La(SS‐B) antibody to the hypergammaglobulinaemia seen in primary Sjögren's syndrome is unknown. In this study levels of anti‐La(SS‐B) antibody directed against three immunodominant epitopes of the anti‐La(SS‐B) autoantigen were measured by ELISA in 84 anti‐La(SS‐B)+ sera using purified recombinant protein and antibody affinity‐purified against the three anti‐La(SS‐B) fusion proteins. There was marked variation in the amounts of IgG anti‐La(SS‐B) antibody detected, with levels ranging from 0.02 mg/ml to 11 mg/mt. The anti‐La(SS‐B) levels were > 1 mg/ml in 61% of patients; in 18% of sera the anti‐La(SS‐B) level constituted 10% or more of the total serum IgG. However, other patients were seen with marked hypergammaglobulinaemia and low anti‐La(SS‐B) concentrations. These results support an antigen‐driven mechanism for the anti‐La(SS‐B) response and suggest that anti‐La(SS‐B) antibody production is regulated independently of other immunoglobulins.
|Number of pages||5|
|Journal||Clinical & Experimental Immunology|
|Publication status||Published - Sep 1991|
- anti‐La(SS‐B) antibody concentration
- immunodominant autoepitopes