Among the CSF leukocytes, higher percentage of CD4+ T cells were found in patients with asymptomatic (41.8%±2.3%, P<0.01) and parenchymal (46.4%±2.1%, P<0.001) neurosyphilis compared with syphilis patients without neurological involvement (29.7%±2.4%) (Table 3). The gene discussed is CD4; the disease is syphilis.