Immunohistochemistry For The Detection Of Treponema Pallidum

Objective:The incidence of syphilis is increasing over the world. The diagnosis of syphilis remains challenging due to its diverse clinical manifestations or incomplete medical history. Similarly, the serological tests and the histopathology changes do not always fulfill the typical diagnostic criteria. Thus, we used immunohistochemistry for direct detect of Treponema pallidum in all the samples, observed the quantity and location of Treponema pallidum in different lesions and clinical phases. The object of this study was to evaluate the contribution of immunohistochemistry for the identification and localization of Treponema pallidum.Methods:A series of20paraffin-embedded lesion biopsy samples of14patients from SRRSH during2004.4to2012.5, with primary, secondary or tertiary syphilis were collected for this study. We reviewed the clinical information of these patients, including clinical manifestations, syphilis serological tests and histopathological results. All of these samples were assessed for detection of Treponema pallidum (TP) by immunohistochemistry. The number and location of TPs for each sample was recorded. The connections between the quantity/location of TPs and the clinical stages or clinical lesions were analysis. We also oberserved changes about number of TPs before and after treatment. Spearman correlation analysis (SPSS17.0) was used to test if there was any correlation between the results of RPR and TP-IHC.Results:Using immunohistochemistry for detection of Treponema pallidums in tissue, we detected the presence of TPs in80%of all the20samples.83.3%of6samples from four patients with primary syphilis,100%of10samples from eight patients with secondary syphilis, and25%of4samples from two patients with tertiary syphilis were TPs positive staining. Of these, the positive predictive value and negative predictive value for all stage was100%.In lesions from primary syphilis, TPs present in the lower part of the epidermis or around blood vessels of dermis in skin lesions, and present around blood vessels or tissues near serosa in rectal lesions. In lesions from secondary syphilis, we saw TPs presenting in all layers of epidermis, around cutaneous appendages and around blood vessels in dermis with inflammations. In an enlarged lymph node from a secondary syphilis patient, we saw that TPs present in inflammatory granulation tissues around lymphoid follicles except in the lymphoid follicles. In a sample of ulcer of chest wall from tertiary syphilis, TPs present in the blood vessels. Besides, we found the quantity of TPs was associated with clinical lesions. There were more TPs in the samples of syphilis chancre, syphilis intestinal inflammation and condyloma latum. Fewer TPs in the samples of squamous erythema, greyish-black plaque, ulcer of chest wall from tertiary syphilis. Also, we observed that the immunohistochemistry staining was TPs negative in a sample after regular therapy, while it was TPs positive before therapy. There were no correlations between the quantity of TPs and the RPR titor.Discussion and Conclusions:Discussion:In this study, immunohistochemistry of Treponema pallidum was used for the diagnosis of syphilis. The positive predictive value and negative predictive value all reached100%, showing the high specificity of this method for diagnosis of syphilis. TPs present in all lesions from patients in all stages of syphilis including one suspected patient in’window phase’. And more TPs present in the lesions of patients in early stages.The results revealed, it’s of high sensitivity for the diagnosis of syphilis and valuable for the diagnosis of syphilis in early stages, especially for patient with negative serological tests. In specimens from syphilis proctitis, we observed that the TPs staining was negative after anti-TP therapy, while TPs staining was positive before therapy.Whats more, we observed that the quantity of TPs was almost equal in the lesions from one patient with greyish-black plaque before and after Benzathine Benzylpenicillin therapy, who is resistant for that. Thus, TP-IHC can be used for the surveillance and evaluation of therapy. TPs present in lower part of epidermis or perivasculary, as’endotheliotropic pattern’and/or’epitheliotropic pattern’.Conclusions:1, Immunohistochemistry of Treponema pallidum is of both high sensitivity and specificity for the diagnosis of syphilis, improving the positive rate of clinical diagnosis for syphilis.2, TPs present in lower part of epidermis or perivasculary, as’endotheliotropic pattern’ and’epitheliotropic pattern’or in the inflammatory granulation tissue. There are no correlations between the quantity of TPs and the result of RPR.3, TP-IHC is helpful for the diagnosis of syphilis, especially for the diagnosis of early suspected syphilis with negative serological test, systemic damage of syphilis with low RPR, syphilis in untypical locations and unusual lesions.4, TP-IHC can be use for the diagnosis of syphilis relapse and the evaluation of anti-TP therapy.5, Applying TP-IHC to detect TPs in clinical lesions is a hopeful test for the clinical practice.