SYPHILIS SEROLOGIES

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ALT CULTURE CLUB TOPIC

SYPHILIS SEROLOGIES

SYPHILIS is probably one the oldest diseases in the world and it is here to stay till judgment day.  It is a contagious venereal disease, almost always transmitted by direct sexual contact, caused by a spirochete known as Treponema pallidum. 

It leads to many structural and cutaneous lesions and if not cured immediately, can cause blindness and mental abnormality.  In most cases, when the organisms are unable to penetrate the intact skin, they enter the body through a microscopic break in the epidermal layer.  Immediately after entrance, the majority of spirochetes remain at the site of infection when they have multiplied sufficiently, or when the reactivity of the body to their products has changed well, the characteristic inflammatory response known as chancre develops.  The stage is called primary syphilis and occurs within 10 to 90 days.  The chancre may last from one to three weeks and may heal spontaneously or with treatment.  Primary syphilis is diagnosed by the observation of chancre and darkfield detection of the causative agent.  Then, two or twelve weeks after the healing of primary chancre, generalized skin rash appears with spirochetes demonstrable in the lesions and this stage is called secondary syphilis.  It is characterized by an enlarged lymph glands, sore throat, headache and patchy falling of hair.  Secondary symptoms usually disappear within about three weeks and may reappear during relapses.  Observation of the characteristic skin lesions, darkfield detection of T. pallidum and increasingly positive serologic tests for syphilis is helpful in the diagnosis of secondary syphilis.  There is the stage where in clinical signs and symptoms of infection are absent and it is called latent syphilis.  Persistent reactions in the serologic tests for syphilis occur in this stage of disease, which may persist for aperiod of time and then develop to the following possibilities:

1. 
   
   It may continue throughout the life of the infected individual.


2. 
   
   It may terminate with the spontaneous cure of infection.


3. 
   
   It may result in late syphilis.

Late symptomatic syphilis maybe characterized by blindness, insanity, paralysis, vascular disease, lost of position sense, destructive ulcers of the skin and mucous membrane.  The diagnosis of late syphilis depends upon the characteristic lesions and occurence of confirmed reactive serologic tests.

In the serodiagnostic flocculation test of syphilis, it is based upon the ability of antigen to combine with syphilitic reagin.  The antigens used are particles of lipid-coated cholesterol with or without beef heart cardiolipin.  The lipid-coated cholesterol functions by forming larger, monstrous particles with tissue lipid extracts and upon combining with reagin gives observable results.  There are various serological tests employed in the laboratory -- Rapid Plasma Reagin (RPR), Unheated Serum Reagin (USR) and RPR card tests.  These are only screening tests and must not be used for final diagnosis.  There are never tests which are intended to detect what appear to be true specific anti-treponemal antibodies using living or killed Treponema pallidum suspensions.  This has been a major breakthrough in syphilis serology and has resulted in the development of a great many tests which have been shown to be highly specific in the diagnosis of this disease.  Among these are Treponema pallidum Immobilization (TPI), VDRL test, Reiter Protein Complement Fixation (RPCF) and Fluorescent Treponemal Antibody-200-ABS (FTA-200-ABS) tests.

Interpretation of serodiagnostic tests for syphilis -- the clinical interpretation of results is primarily the responsibility of the patient's physician.  However, it must be well understood by the lab technologist that a positive test for syphilis simply means that, by the procedure used, a substance reacting with the antigen is present in the serum and not necessarily that the patient has the disease in question.  False positive reactions, excluding those obtained by technical errors are not rare.  These can be found in intercurrent diseases (malaria, leprosy, lupus erythematosus) or in some individuals who have no condition apparent that could account for the reaction obtained.  These phenomena are called "biological reactors."  Non-specific reactions in serologic syphilis have induced researchers to exert more efforts to develop a more excellent serodiagnostic test and also to obtain a higher standard of realibility and accuracy. 

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