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Serological Reactions in Various Forms of Syphilis



The IFT and Kolmer's test, as the most sensitive serological reactions, may be positive in the primary seronegative period of syphilis. This, in accordance with the regulations adapted however, cannot be accepted as a basis for the diagnosis of primary seropositive syphilis. Some patients produce an isolated positive result of Wassermann's reaction with a treponemal or cardiolipin antigen in this period.

At the end of the third or during the fourth weeks after the appearance of primary syphiloma, the standard serological reactions become positive; the primary seropositive period of syphilis begins from this point. In the first to second week of the primary seropositive period, the results of serological reactions become positive (1-2-3-4 +) and the reagin titre grows (1: 5, 1: 10, 1: 20, etc.). The IFT and Kolmer's test are already sharply positive in all patients; the TPI is negative, as a rule or the immobilization percentage is very low. Primary seropositive syphilis is also diagnosed in patients in whom the Wassermann's reaction with non-specific antigens have yielded even a single weakly positive result. With further development of primary syphilis all serological reactions become sharply positive, the reagin titre grows (to 1: 80, 1: 160), the IFT remains sharply positive, but the TPI in most patients is still negative or weakly positive.

In secondary early syphilis the result of all standard serological reactions is sharply positive in almost 100 per cent of cases, the reagin titre is highest (1: 160, 1: 240, 1: 320), the IFT is 4+ and the TPI is positive in more than half the patients, but treponema immobilization is low (40-60 per cent).

In secondary recurrent syphilis the standard serological reactions are positive in 96 to 98 per cent of cases (a negative result may be found in monosymptomatic recurrent syphilis and in emaciated patients), the reagin titre tends to decrease (1: 60, 1: 80), the TPI is positive in 85 to 90 per cent of patients, immobilization is pronounced (80-90-100 per cent).

The tertiary syphilis is characterized by positive results of the standard serological reactions in 50 to 90 per cent of cases and positive TPI in 98 to 100 per cent of cases (in high immobilization percentage).

As it is noted in the respective section, the diagnosis of late latent seropositive syphilis is made only on the basis of positive blood serological reactions with compulsory verification by the TPI because mainly this test (and, to a lesser extent, the IFT) allows true syphilitic (even 2+ or 3+) and false positive, non-syphilitic serological reactions to be differentiated.

The various forms of syphilis of the nervous system and visceral organs differ in the frequency and pronounced character of positive standard serological reactions. General paresis, for instance, is attended with sharply positive standard serological reactions in 100 per cent of cases; in syphilis of the cerebral vessels, tabes dorsalis and syphilitic affection of the cardiovascular system, these reactions are positive in only 40-50-60 per cent of cases. The TPI, however, is sharply positive (90 to 100 per cent immobilization) almost in all of these patients.

In congenital syphilis the standard serological reactions are not determinative in the first two months of life because they may be positive due to passive transmission of the reagins through the placenta. A positive result of the TPI is also of no significance since the immobilizins transmitted passively from the mother to the foetus disappear spontaneously within six months after birth. When infection occurs just before birth, the TPI will still be negative (because the immobilizins form later in this case), despite the presence of the syphilitic infection in the infant's body. In congenital syphilis with active manifestations, the standard serological reactions may be negative in 1 per cent of infants and in congenital syphilis of early childhood in 15 to 25 per cent of children (the TPI in the latter case, however, is positive in 90 to 98 per cent of children). In late congenital syphilis even in the presence of active manifestations, the standard serological reactions are positive in only 70-80 per cent of patients examined, whereas the TPI is positive almost in 100 per cent of cases.


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