Sharon A. Baker-Zander

Invasion of the Central Nervous System by Treponema pallidum: Implications for Diagnosis and Treatment

STUDY OBJECTIVES To determine the prevalence of Treponema pallidum in cerebrospinal fluid (CSF) of patients with syphilis, to determine the effect of concurrent HIV infection on central nervous system involvement by T. pallidum, and to examine the efficacy of conventional therapy for asymptomatic neurologic involvement. PATIENTS Fifty-eight patients with untreated syphilis who consented to lumbar puncture, representing approximately 10% of new cases of syphilis during the study period. INTERVENTIONS Lumbar puncture was done on all patients. Rabbit inoculation was used to test cerebrospinal fluid for viable T. pallidum. Patients with normal fluid received recommended benzathine penicillin therapy according to the stage of syphilis; patients with CSF abnormalities were offered 10-day therapy for neurosyphilis. RESULTS Treponema pallidum was isolated from the CSF of 12 (30%) of 40 patients (95% CI, 17 to 46) with untreated primary and secondary syphilis; isolation of T. pallidum was significantly associated (P = 0.008) with the presence of two or more abnormal laboratory variables (among leukocyte count, protein concentration, and CSF-Venereal Disease Research Laboratory [VDRL] test). Two (67%) of 3 early latent (CI, 13 to 100) and 3 (20%) of 15 late latent syphilis patients (CI, 5 to 47) also had reactive CSF-VDRL tests and elevated cell and protein levels, although T. pallidum was not isolated. Concurrent infection with the human immunodeficiency virus (HIV) was not associated with isolation of T. pallidum, increased number of CSF abnormalities, or reactive CSF serologic tests for syphilis, although CSF pleocytosis was commoner in subjects infected with HIV. Treatment with conventional benzathine penicillin G (2.4 mIU) failed to cure 3 of 4 patients with secondary syphilis from whom T. pallidum was isolated before therapy; all 3 patients in whom treatment failed were HIV seropositive when treated or seroconverted during follow-up. CONCLUSIONS Central nervous system invasion by T. pallidum is common in early syphilis, and is apparently independent of HIV infection. Examination of the CSF may be beneficial in patients with early syphilis, and therapy should be guided by knowledge of central nervous system involvement. Conventional benzathine penicillin G therapy may have reduced efficacy in patients with early syphilis who are also infected with HIV.

Identification of Spirochetes Related to Treponema pallidum in Necrotizing Ulcerative Gingivitis and Chronic Periodontitis

BACKGROUND Spirochetes are commonly associated with periodontal disease, but it is not known whether these treponemes are pathogenic or merely opportunistic. We sought to determine whether spirochetes present in periodontal disease share antigens thought to be unique to spirochetes that are known pathogens. METHODS We examined dental plaque from 24 healthy subjects, from ulcerative sites in 17 patients with ulcerative gingivitis, and from areas of involvement in 19 patients with chronic periodontitis, using an immunocyto-chemical technique with monoclonal antibodies against pathogen-specific determinants on 47-kd and 37-kd molecules from Treponema pallidum subspecies pallidum. Serum was tested against T. pallidum by immunoblotting and by serologic assays for syphilis. RESULTS Spirochetes with a pathogen-specific epitope on a 47-kd molecule were not found in plaque samples from any of the 24 healthy subjects, but they were identified in plaque samples from 11 of 17 patients with ulcerative gingivitis (P less than 0.001) and from 10 of 19 patients with periodontitis (P less than 0.01). Monoclonal antibodies directed against a 37-kd molecule reacted with spirochetes in plaque samples from 1 of 14 controls, from all 11 patients with gingivitis from whom samples could be obtained (P less than 0.001), and from 14 of 19 patients with periodontitis (P less than 0.001). Five of 18 normal subjects had IgG against 47-kd and 37-kd molecules, but none had IgG against 14-kd or 12-kd molecules from T. pallidum subspecies pallidum. Among 19 patients with ulcerative gingivitis, IgG was identified against 47-kd molecules in 15, against 37-kd molecules in 12, against 14-kd molecules in 4, and against 12-kd molecules in 15. CONCLUSIONS The spirochetes found in dental plaque from patients with ulcerative gingivitis or chronic periodontitis have antigens that are thought to be unique to pathogenic treponemes. This close antigenic relation suggests that T. pallidum or a closely related organism may be involved in the pathogenesis of periodontal disease.

Ceftriaxone therapy for asymptomatic neurosyphilis. Case report and Western blot analysis of serum and cerebrospinal fluid IgG response to therapy.

A 27-year-old man with documented hypersensitivity to penicillin was treated intramuscularly for asymptomatic neurosyphilis with ceftriaxone (1 g daily for 14 days). After treatment the serum titer in the VDRL (Venereal Disease Research Laboratory) test declined from 32 to four dilutions. Lumbar punctures at months 3, 6, 9, and 28 after treatment revealed normalization of the cell count in cerebrospinal fluid and a decline in the VDRL titer in cerebrospinal fluid from four to one dilution(s). Western blot analysis revealed the presence in serum of IgG antibodies to at least 17 treponemal antigens and in cerebrospinal fluid of antibodies to at least ten treponemal antigens. Following ceftriaxone therapy serum and cerebrospinal fluid IgG reactivity to all antigens steadily decreased in intensity. These results indicate that ceftriaxone may provide a useful alternative therapy for penicillin-allergic patients with neurosyphilis.

IgG and IgM antibody reactivity to antigens of Treponema pallidum after treatment of syphilis

The persistence or loss of IgG and IgM antibody specificities for individual polypeptides of Treponema pallidum after therapy for syphilis was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and by the Western blot technique. Both IgG and IgM antibodies to as many as 12 treponemal antigens, including a major 47-kdalton molecule, were evident in plasma from patients with untreated primary syphilis. IgM reactivity declined rapidly and uniformly after therapy, whereas IgG persisted despite some diminution in intensity of staining. Faint-to-moderate IgM and strong IgG antibody reactivities to at least 22 treponemal antigens (12-85 kdaltons) were identified in plasma from patients with untreated secondary and early latent syphilis. Again, IgG antibody declined slightly in staining intensity after treatment but continued to show reactivity against all molecules detected initially. IgM antibody reactivity declined more rapidly and was lost entirely against some determinants, including the 14- and 12-kdalton molecules. Immunofluorescence titers of IgG and IgM antibodies to T. pallidum in sera from these patients generally correlated with results of Western blot analysis. Antibody to the 12-, 14-, and 47-kdalton molecules of T. pallidum may have potential diagnostic applications.

Clinical course and treatment of venereal spirochaetosis in New Zealand white rabbits.

Ten sporadic cases of venereal spirochaetosis, caused by Treponema paraluis-cuniculi, were seen in New Zealand white rabbits in two years. An equal number of males and females were affected. Females tended to have milder clinical signs than males. Lesions were usually found on the prepuce in males and the vulva in females, although the anus and skin of the perineum were also affected. Facial lesions were rare. Lesions healed in seven to 28 days in rabbits treated with penicillin. Eight rabbits had antibodies reactive in the Venereal Disease Research Laboratory (VDRL), rapid plasma reagin (RPR), and fluorescent treponemal antibody absorbed (FTA-ABS) tests when the disease was first diagnosed. In several rabbits followed longitudinally, RPR test results became negative two to four months after antimicrobial treatment, VDRL antibody titres diminished but usually persisted at low levels, while FTA-ABS antibodies declined slowly and were still evident 12 months after treatment.

Chronicity of infection with Treponema paraluis-cuniculi in New Zealand white rabbits

Popliteal lymph nodes from eight New Zealand white rabbits with clinical or serological evidence of naturally acquired infection with Treponema paraluis-cuniculi were transferred to rabbits that had not been exposed to this infection. Lymph nodes from two rabbits successfully transmitted infection. The nodes from one of these rabbits transmitted infection during both the acute and chronic stages of infection. Recipients that were successfully infected showed concomitant antibody responses in the Venereal Disease Research Laboratory (VDRL), rapid plasma reagin (RPR), and fluorescent treponemal antibody-absorption (FTA-ABS) tests six to 10 weeks after inoculation; recipients of uninfected nodes showed no change in serological state. Antibody responses were followed by the development of dark field positive genital lesions 14 to 15 weeks after inoculation.

Experimental neonatal syphilis. II. Immunological responses of neonatal rabbits to intradermal inoculation with Treponema pallidum (Nichols strain)

Summary: The immunological competence of neonatal rabbits inoculated intradermally with Treponema pallidum was examined. Both cellular responses and the production of humoral antibody to specific T. pallidum antigens and to nonspecific antigens or mitogens were investigated. In blast transformation assays, splenic and popliteal lymph node lymphocytes from neonates inoculated with virulent T. pallidum responsed to T. pallidum antigens in a manner similar to or greater than inoculated adult rabbits. Splenic and popliteal lymph node lymphocytes from both uninoculated and T. pallidum-inoculated neonate and adult animals showed consistent and similar responses to concanavalin A. Both neonate and adult animals inoculated with heat-killed T. pallidum also responded but to a significantly lesser degree. Immunofluorescent examination of skin sections from the site of inoculation of adult and neonatal animals revealed 1) that the early infiltrate was composed predominntly of T cells, 2) diffuse antibody staining with rare B cells, and 3) fewer treponemes with significant fragmentation in neonates as compared to adult controls. Antibody production by neonates inoculated with virulent T. pallidum was delayed 4 to 6 weeks postinoculation as measured by the fluorescent Treponemal antibody absorption and Venereal Disease Research Laboratory (VDRL) test procedures, respectively. Antibody was not detected among neonates inoculated with heat-killed treponemes during a 6-week observation period and only low levels of VDRL antibody were detected in a few adult control animals.Evidence for incomplete resistance of neonatal rabbits to the intradermal inoculation of Treponema pallidum was provided. Twenty-two of 23 neonatal rabbits resistant to symptomatic infection upon initial inoculation with treponemes were also resistant to homologous challenge 3 to 5 months later, thus indicating a refractive state. Additional evidence was provided by the appearance of generalized lesions among seven of 29 neonates.