IgG avidity test for the diagnosis of acute Toxoplasma gondii infection in early pregnancy.
BACKGROUND
Toxoplasmosis is well known as an important infection in pregnant women. Although many serologic methods are available, diagnosis of early Toxoplasmosis may be extremely difficult.


OBJECTIVE
To detect the Toxoplasma IgG antibodies developed at the early stage of infection in pregnant women.


METHODS
225 pregnant women, who were in the 2nd to 4th month of their pregnancy, enrolled in this study. Anti-toxoplasma IgG, IgM and IgG avidity were evaluated by ELISA method.


RESULTS
The patients were categorized into three groups as follows: Group A, 124 cases; IgG+, IgM+, 55.1%; group B, 99 cases; IgG+, IgM-, 44%; and group C, 2 cases; IgG -, IgM +, 0.9%. Fifty five percent of the pregnant women had positive IgG and IgM among which 7.1% had low avidity which revealed an active infection in the pregnant women. In the current study, 44% of pregnant women had positive IgG and negative IgM, all of which had high avidity, which is an indication that in our population the level of toxoplasmosis infection is high and most women have had contacts with this parasite before pregnancy.


CONCLUSIONS
In this study, the low avidity test was 7.1% showing that the occurrence of toxoplasmosis infection is still a serious issue. Observation of 45.8% high avidity among group A suggests that either IgM has a high half-life or there is a false positive IgM as a result of rheumatologic disorders. Therefore, avidity test is important in predicting maternal toxoplasmosis which is of value in disease treatment.
Department of Immunology, Faculty of Medicine and Drug   Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran, e-mail: bonyadir@tbzmed.ac.ir.
Shabnam
S
Pour Abolghasem
Mohammad Reza
MR
Bonyadi
Zohre
Z
Babaloo
Abolfazl
A
Porhasan
Behroz
B
Nagili
Omid Ali
OA
Gardashkhani
Parviz
P
Salehi
Mohammad
M
Hashemi
Mojtaba
M
Varshoghi
Gafar Olade
GO
Gaffari
D000208:Acute Disease; D000915:Antibody Affinity; D000953:Antigens, Protozoan / Q000276:immunology; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D011237:Predictive Value of Tests; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000175:diagnosis* / Q000276:immunology; D011379:Prognosis; D012107:Research Design; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000175:diagnosis* / Q000276:immunology
D000953:Antigens, Protozoan; D007074:Immunoglobulin G