QLIPS detection of anti-La autoantibodies. QLIPS detection of autoantibodies against La in 25 normal controls and 57 primary SjS patients. Each circle or square symbol represents the anti-La antibody titer of a normal control or SjS patient, respectively. The solid lines represent the GMT for each group. For determining sensitivity and specificity for this anti-La antibody test, the dashed line represents the cut-off level derived from mean plus 5 SD of the antibody titers of the 25 normal volunteers.