The performance of rapid plasma reagin (RPR) titer in HIV-negative general paresis after neurosyphilis therapy

Abstract Background Repeated nontreponemal serologic test for syphilis titers is recommended to evaluate treatment response. However, it is unknown whether serum rapid plasma reagin (RPR) titer can serve as a surrogate for determining the efficacy of treatment in general paresis (GP) remains unknown. Methods We retrospectively reviewed data from 105 GP patients, who were divided into two groups (62 CSF RPR+ patients and 43 CSF RPR- patients) according to reactive RPR test status in CSF. Clinical assessment included the Mini-Mental State Examination (MMSE) scores, CSF examinations (WBC count, protein concentration and RPR titer), and serum tests (RPR titer and TPPA). Among the 105 GP patients, 13 CSF RPR+ patients and 6 CSF RPR- patients had a 12 months follow-up of CSF, serum measures and MMSE. Results The median serum RPR titer was significantly higher in CSF RPR+ patients than that in CSF RPR- GP patients, 1:8 [IQR 1:4–1:32] vs. 1:4 [IQR 1:4–1:8] (P