926 CASE AND RESEARCH LETTERS Usefulness of Immunohistochemial Staining With Antitrepenomal Antibodies in the Diagnosis of Syphilis

Utilidad de la inmunohistoquímica con anticuerpos antitreponema en el diagnóstico de la sífilis To the Editor: Syphilis is a sexually transmitted infection (STI) caused by the spirochete Treponema pallidum pallidum. Recent years have seen a resurgence of syphilis. This is mainly due to an increased number of cases diagnosed in men who have sex with men (MSM).1 Infection is associated with erratic condom use and a high number of sexual partners in the months before diagnosis.2 In Spain the incidence of syphilis has tripled since the beginning of this century, increasing from 1.96 to 5.70 per 100 000 population between 1998 and 2008..1,3 Even with effective treatment, the disease remains a significant public health problem with high associated eco-nomic costs.2,3 Correct diagnosis is crucial in order to start antibiotic therapy as soon as possible and thus prevent new infections and stop the progression of the disease and associ-ated sequelae.4 Accordingly, new, more effective diagnostic techniques are required. Traditionally the diagnosis of syphilis is based on a combi-nation of clinical signs and symptoms, serological tests, and direct detection of the organism using dark field microscopy and silver impregnation techniques.1,5,6 A definitive diag-nosis can be reached only by direct detection of the microorganism in infected tissues.