Predictive factors of asymptomatic neurosyphilis among syphilis patients with human immunodeficiency virus-negative

Abstract

Objective To investigate the predictive factors of asymptomatic neurosyphilis in syphilis patients with human immunodeficiency virus (HIV) negative. Methods From May 2014 to January 2018, a total of 162 cases of syphilis with HIV negative and no symptoms of nervous system involvement in Beijing Ditan Hospital, Capital Medical Unversity were analyzed, retrospectively, including 79 cases of noral syphilis and 83 cases of asymptomatic neurosyphilis. The levels of treponema pallidum particle assay (TPPA), toluidine red unheated serum test (TRUST), fluorescent treponemal antibody-absorption IgG (FTA-ABS-IgG), fluorescent treponemal antibody-absorption IgM (FTA-ABS-IgM) in blood and cerebrospinal fluid (CSF) and the results of leukocyte and protein detection in CSF were compared between the two groups. Results The geometric mean titer of serum TRUST was 1: 13.09 in asymptomatic neurosyphilis group and 1: 4.73 in noral syphilis group (Z =-5.344, P < 0.001). Serum TRUST titer was positively correlated with asymptomatic neurosyphilis (r = 0.421, P < 0.001). Serum TRUST titer ≥ 1︰8 was positively correlated with asymptomatic neurosyphilis (r = 0.362, P < 0.001). Serum FTA-ABS-IgM was positively correlated with asymptomatic neurosyphilis (r = 0.232, P = 0.002). Conclusions The serum TRUST titer of asymptomatic neurosyphilis with HIV negative is higher than that of syphilis. The higher the serum TRUST titer was, the greater the risk of asymptomatic neurosyphilis was. Serum TRUST titer ≥ 1︰8 and positive serum FTA-ABS-IgM both suggested asymptomatic neurosyphilis. Key words: Asymptomatic neurosyphilis; Lumbar puncture; Treponema pallidum particle assay; Toluidine red unheated serum test; Fluorescent treponemal antibody-absorption