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Serological tests in cerebrospinal fluid for congenital syphilis in central Africa
Insights
The Venereal Disease Research Laboratory (VDRL) test is insensitive for diagnosing congenital neurosyphilis in children. Fluorescent treponema antibody absorption (FTA-ABS) or Treponema pallidum haemagglutination assay (TPHA) tests are more suitable when specific IgM detection is unavailable.
Area of Science:
- Pediatric Infectious Diseases
- Neurosyphilis Diagnostics
- Serological Testing
Background:
- Congenital syphilis poses significant risks to newborns, potentially leading to neurosyphilis.
- Accurate serological diagnosis in cerebrospinal fluid (CSF) is crucial for effective treatment.
Purpose of the Study:
- To evaluate the sensitivity and utility of different serological tests for diagnosing active congenital neurosyphilis in children.
- To compare the effectiveness of VDRL, TPHA, and FTA-ABS tests in CSF samples.
Main Methods:
- CSF samples from 13 children with active congenital syphilis and 7 seropositive controls were analyzed.
- Tests performed included VDRL, TPHA, and FTA-ABS (IgG and IgM).
Main Results:
- CSF-VDRL was negative in all children with active congenital syphilis.
- CSF-FTA-ABS IgG was positive in 7/13 active cases, but not correlated with clinical severity or CSF parameters.
- CSF-TPHA was positive in 4/12 active cases.
Conclusions:
- The VDRL test lacks sensitivity for diagnosing congenital neurosyphysis.
- FTA-ABS and TPHA are more convenient alternatives for CSF analysis in congenital neurosyphilis, though false positives can occur.
Abstract:
Serological tests were performed in the cerebrospinal fluid (CSF) of 13 children with active congenital syphilis (presence of specific IgM FTA-ABS antibodies) and of seven seropositive children with no active syphilis (FTA-ABS IgM-negative) born to syphilitic treated mothers in Libreville, Gabon. Antibodies against treponema were measured by the Venereal Disease Research Laboratory test (VDRL), the Treponema pallidum haemagglutination assay (TPHA) and the fluorescent treponema antibody absorption tests (FTA-ABS IgG and IgM). Of the 13 children with active syphilis, seven had a positive FTA-ABS IgG in the CSF. The result of this test was not correlated with the severity of clinical features, CSF protein levels or number of CSF white blood cells. The CSF-TPHA test was positive in four out of 12 children, and the CSF-VDRL test was negative in all the children with active congenital syphilis. One of the seven newborns with mother-transmitted antibodies had a positive FTA-ABS and TPHA in the CSF. These data show that the VDRL is not sensitive enough to diagnose congenital neurosyphilis, and that FTA-ABS or, at least, TPHA are convenient, sometimes with false-positive results, when a sophisticated method of detecting specific IgM in CSF is not available.