The relationships between titers of anti-Ro or anti-La as measured by ELISA and salivary production rate with age correction.

The objective of this work was to clarify the clinical significance of titers of anti-Ro and anti-La, the relationships between titers of either anti-Ro or anti-La, and salivary production rate (SPR). These autoantibodies were titrated using enzyme-linked immunosorbent assay. The Saxon test was performed to measure SPR. Fifty-one females who had anti-Ro but not anticentromere antibodies or anti-U1RNP were enrolled. SPR decreased significantly with age. In order to exclude the effect of aging on SPR, we calculated the "SPR with age correction." According to the results of a multiple regression analysis, only the anti-La titer was significantly associated with SPR with age correction. The distribution pattern of the anti-La titers consisted of two subgroups (with a titer index cutoff of 100.0): a negative anti-La titer (anti-La<25.0) and low anti-La titer (25.0or=100.0). The concentration of serum IgG and the frequency of Sjögren's syndrome in the high anti-La titer group were significantly higher than those in the negative anti-La and low anti-La titer group. Several new aspects of the clinical significance of titrating anti-Ro and anti-La in comparison with SPR have been revealed.