An atypical, "beaded" pattern of fluorescence of the Treponema pallidum antigen has been reported to occur when sera from certain patients with lupus erythematosus (LE) are tested in the fluorescent treponemal antibody-absorption (FTA-ABS) test. In the present case, follow-up of a reactive Venereal Disease Research Laboratory (VDRL) slide test led to detection of a beaded fluorescence pattern in the FTA-ABS test. Awareness and reporting of this atypical fluorescence provided the initial clue that led to the diagnosis of LE.
Kraus SJ, Daniels KC. Atypical FTA-ABS Test ReactionAn Initial Clue in the Diagnosis of Lupus Erythematosus. Arch Dermatol. 1971;104(3):260-261. doi:10.1001/archderm.1971.04000210034006