Anne Decoster

Anti-P30 IgA antibodies as prenatal markers of congenital toxoplasma infection

This study extends a previous study and confirms that the detection of anti‐P30 IgA antibodies is very helpful in the diagnosis of acute acquired or congenital toxoplasmosis. Moreover, we demonstrate that an anti‐P30 IgA response can be mounted in the fetuses infected by Toxoplasma gondii during their inira‐utcrine life as early as week 23 of gestation. A double‐sandwich ELISA described in our previous work was used to detect anti‐P30 IgA antibodies in 1378 human serum samples collected from 551 patients, including 162 fetuses whose mothers had been infected by T. gondii during pregnancy, 46 congenitally infected and 90 uninfected newborns and 253 women suspected of having been infected during pregnancy, including the mothers of fetuses and newborns previously described. Anti‐P30 IgA antibodies were detected in all cases of acute toxoplasmosis but in no case of chronic toxoplasmosis: in the majority of cases, the IgA antibody litre fell below cut‐off in 3–9 months. Among the 46 congenitally infected newborns, anti‐P30 IgA antibodies were detected in sera of 41 infected newborns (38 at birth, two in the first months of life, one in the seventh month of life), while anti‐P30 IgM antibodies were detected in only 30 cases at birth and in one case during the first month of life. Among 162 fetuses, anti‐P30 IgA response was observed in five infected fetuses, but was not detected in either 152 uninfected fetuses or in five fetuses considered as infected. The absence or presence of anti‐P30 IgA antibodies in the fetus is discussed in relation to the date of maternal infection and collection of the fetal blood. It clearly appears from our study that the combined testing of both IgM and IgA in the fetus and the newborn is essential for a more efficient diagnosis of infection.

Routine practice HCV infection screening with saliva samples: multicentric study in an intravenous drug user population.

OBJECTIVE The purpose of this randomized multicentric study was to evaluate the diagnostic contribution of screening for HCV infection on saliva samples in day-to-day practice in the intravenous drug-user (IVDU) population. METHODS Between January and May 2004, 274 presumably HCV-negative IVDU were screened for HCV infection in 15 centers in France (median age 29 years). After centralized randomization, screening tests were performed on blood samples (arm A) or saliva samples (arm B). Screening tests were performed in 78 subjects (28%) had never been screened before and in 196 subjects (72%) who had had a negative HCV screening test on average 12 months prior to the beginning of the study. In the event of a positive saliva test for anti-HCV Ab, a serum test for anti-HCV Ab was performed. In the event of a positive serum test for anti-HCV Ab, PCR was performed on serum to measure HCV-RNA. RESULTS Fourteen individuals were positive for HCV RNA (7 in each arm). Six of these cases had not been detected before. In eight cases, the median time between the last negative screening test and study inclusion was 11 months (range 6-94 months). CONCLUSIONS Viremia tests were positive in 5% percent of the target population, although one-third of the individuals in arm A (blood samples) were not tested. The saliva test may be a useful alternative in the event of refusal of a blood test or when poor venous conditions compromise venous puncture. A confirmatory blood test still remains difficult to obtain in nearly half of patients.

Acute hepatitis C during the third trimester of pregnancy

A pregnant woman presented at 32 weeks of amenorrhea with jaundice secondary to acute hepatitis C. Spontaneous delivery took place 3 days later. The infants serum tested negative for C viral RNA 6 months after delivery. Treatment with high doses of interferon-alpha for a period of 4 weeks was begun 4 days after delivery. Although a virological response was noted at the end of the treatment, the hepatitis relapsed and progressed toward chronicity. Case reports of acute hepatitis C during pregnancy are very rare, as the methods used for the follow-up of pregnant women render the diagnosis of asymptomatic forms difficult. In one case, the acute hepatitis C was severe. The occurrence of acute hepatitis C during pregnancy seems to increase the risk of premature delivery, but not that of vertical transmission. Given the frequency of side effects, it seems preferable not to begin interferon treatment until after delivery.

An inter-laboratory study of anti-HCV antibody detection in salavary samples

AIM The purpose of this study was to evaluate the efficacy of anti-hepatitis C virus (HCV) antibody detection in the saliva samples of 108 drug users in an inter-laboratory study. METHODS Between January and June 2001, 108 subjects in Lille, Metz and Lens received a test to detect anti-HCV antibodies in their saliva. Two consecutive saliva samples were taken in each subject (Salivette system, Sarstedt). An HCV serology (Axsym HCV 3.0, Abbott) was also performed and serum HCV RNA detection by Amplicor HCV 2.0 (Roche) was performed when HCV serology was positive. Sixty three patients had a negative HCV serology, 45 had a positive HCV serology, and 31 of these had positive HCV RNA as well. Tests for the detection of the anti HCV antibody in saliva samples were performed as a blind study in both the Lille and the Thionville laboratories. RESULTS The sensitivity of saliva anti-HCV antibody tests was respectively 71% (32/45) and 78% (35/45) in Lille and Thionville. In the event of positive HCV viremia, the sensitivity was respectively 90% (28/31) and 93% (29/31). The specificity was respectively 97% (61/63) and 98.5% (62/63). Results from the two laboratories agreed for 101 saliva tests while discrepancies were found in 7 (Kappa Concordance Coefficient: 0.85). CONCLUSIONS This study confirms, in a large, unselected population sample, that anti-HCV antibody detection tests in saliva allow the detection of 90% of viremic HCV-antibody-positive patients with excellent specificity. The simplicity and reproductibility of this technique makes it a precious tool for epidemiological studies.