[ Usefulness of laboratory investigations for the diagnosis of acrodermatitis chronica atrophicans. ]. / Apport de la biologie dans le diagnostic d'une acrodermatite chronique atrophiante.

The authors report a clinical case of acrodermatitis chronica atrophicans in a 65 year old diabetic woman. The characteristic cutaneous lesion restricted to the dorsal aspect of the left hand has been evolved since two years, together with a progressive development of a typical Dupuytren disease. This yielded a contracture of the last 3 phalanges of the same left hand. Confirmatory techniques included the histology of the skin, the reactivity of specific-IgG antibodies showing high avidity and Western blot. Of this, the immunodominant antigens which were extracted from 3 genospecies of Borrelia sensu lato i.e. Bb sensu stricto, Bb garinii, Bb afzelii were compatible with past infection. Apart from the diabetic status which may have predisposed the patient to the development of Dupuytren disease, the authors question about the potential role of Borrelia burgdorferi in the occurrence of this associated disease.

[Followup of pregnant women in the context of malaria: two case reports]. / Suivi de la grossesse dans le cadre du Paludisme: à propos de deux observations.

Whether or not a pregnant women should travel to regions where malaria is highly endemic will always be open to question as no prophlaxis can guarantee complete protection in every case. No chemoprophylaxis is 100% effective or entirely without side-effects, particularly for pregnant women whose immune status provides a favourable environment for the emergence of this parasitosis. The advice given will depend on the country and the region, a possible resistance of the parasite to treatment, the season, the length and circumstances of the stay and individual factors. The choice of treatment is very limited as many therapies are contra-indicated in pregnancy; in addition it is extremely important to give a sufficiently clear explanation concerning precautions and prophylaxis as well as of how a possible bout of malaria should be treated, particularly in case of extended stay.

Multicenter evaluation of strategies for serodiagnosis of primary infection with Toxoplasma gondii.

The diagnostic performance of single-serum assays for toxoplasma-specific immunoglobulin (Ig)M. IgA. IgG, and IgE antibodies and of different combinations of such antibody assays in 20 European reference centers was assessed. A panel of 276 sera, of which 73 came from patients who seroconverted within 3 months (acute infection), 49 from patients who had seroconverted 3-12 months earlier (convalescence), and 154 from subjects who had two IgG-positive samples obtained 12 months apart (past infection), was tested with 20 toxoplasma-antibody assays and 195 combinations. In general, every assay with high diagnostic sensitivity showed low diagnostic specificity, i.e. no assay performed alone could reliably distinguish acute from past infection. Furthermore, no single assay (or combination) could separate convalescence from the other stages of toxoplasma infection. However, excellent diagnostic performances were reached by sequential use of highly sensitive IgM assays and methods examining IgG avidity or stage specificity. IgA or IgM assays were less suitable for confirmation of toxoplasma-IgM positivity. This study documents the strength of test combinations in assessing the stage of toxoplasma infection.

Strategy for diagnosis of congenital toxoplasmosis: evaluation of methods comparing mothers and newborns and standard methods for postnatal detection of immunoglobulin G, M, and A antibodies.

In a study involving 14 laboratories supported by the European Community Biomed 2 program, we evaluated immunologic methods for the postnatal diagnosis of congenital toxoplasmosis (CT). Among babies born to mothers who seroconverted to positivity for toxoplasmosis during pregnancy, we analyzed 55 babies with CT on the basis of persistent anti-Toxoplasma immunoglobulin G (IgG) at 1 year of life and 50 control babies without anti-Toxoplasma IgG at 1 year of life in the absence of curative treatment with pyrimethamine-sulfonamides. We tested in-house methods such as the enzyme-linked immunofiltration assay (ELIFA) or Immunoblotting (IB) for the detection of IgG or IgM; these methods allowed comparison of the immunologic profiles of the mothers and the infants. We compared ELIFA and IB with a commercial enzyme immunoassay (EIA) or in-house immunosorbent agglutination assay (ISAGA) for the detection of IgM or IgA. The performances of combinations of methods were also assessed. A cumulative sensitivity of 98% during a 1-year follow-up was obtained with the ELIFA plus ISAGA combination. Only one case of CT was missed by the ELIFA plus ISAGA combination, whereas three cases were missed by the IB plus ISAGA combination, even though 48% of patients with CT were treated with pyrimethamine-sulfonamides, which are known to inhibit antibody neosynthesis. A similar performance was obtained with either ELIFA or IB in combination with EIA. The difference in performance between ELIFA plus ISAGA and IB plus ISAGA was not statistically significant (P = 0.31), and we conclude that both combinations of tests can be used for the diagnosis of CT in newborns.

An unusual case of anti-Borrelia burgdorferi immunoglobulin G seroconversion caused by administration of intravenous gammaglobulins.

Administration of gammaglobulins to individuals without specific anti-Borrelia burgdorferi antibodies may lead to immunoglobulin G (IgG) conversion as detected by enzyme-linked immunosorbent assay (ELISA). In some cases however, complementary techniques such as Western blot or avidity will be of prime importance in distinguishing the start of an infection from the passive immunization induced by the gammaglobulins. In all cases, the key element before reaching conclusions in relation to any of these investigations remains the confrontation between the clinical context and the biological findings. This is the scenario that has been followed in our observation.

[Congenital toxoplasmosis and seroconversion at the end of pregnancy: clinical observations]. / Toxoplasmoses congénitales et séroconversions de fin de grossesse: observations cliniques.

We report seven cases of subclinical congenital toxoplasmosis secondary to maternal primary infections. Mothers were infected between two and four weeks prior to delivery. The diagnostic criteria of congenital infections included: IgM antibody (Ab) (1 case); IgM and IgA Ab (1 case); a real IgG seroconversion in the neonatal and postnatal samples (3 cases); persistence of IgG Ab beyond 6 months post-delivery (2 cases). A treatment was initiated, including a combination of pyrimethamine + sulfadiazine (6 cases); trimethoprim + sulfamethoxazole (1 case). This retrospective study suggests that it is important to screen the non-immune pregnant women until delivery. We confirmed the usefulness of a combination of isotypes of antibodies for the accurate assessment of congenital infection. Finally, infected infants have to be treated and monitored clinically and immunologically during the first year of life.

A seroepidemiological study on toxoplasmosis.

Using the microparticle capture enzyme-immunoassay (MEIA) based on IMx technology (Abbott), we determined the current prevalence of toxoplasmosis in 784 pregnant women followed up during 1990, and in 1,839 randomly selected blood donors. They all came from the Brabant Wallon area and the South-East of Brussels. Specimens yielding low IgG immunity (6-15 units) [corrected], were further tested with a sensitive direct agglutination assay (Toxo-Screen DA, bioMerieux). Overall, the prevalence was 67% among blood donors and 50% in pregnant women. In blood donors, the prevalence in women was not statistically different from the prevalence in men: X2 = 2.95 NS. In the two populations, a progressive age-related increasing prevalence of up to 60% for pregnant women and 77% for blood donors was observed. In females, the prevalence was higher among female blood donors than among pregnant women: 63% versus 50%, X2 = 16, P < 0.001. However, when the prevalences were compared within three age subgroups of women (< or = 33 yrs, 34 to 41 yrs, > or = 42 yrs), there were no statistically significant differences between pregnant women and blood donors. Thus, the overall observed difference was due to an age effect. Therefore, the distribution of IgG titers was established in each of the six age and sex subgroups. The 25th, 50th and 75th percentiles of those distributions ranged between 14 IU and 20 IU, 24 IU and 35 IU, and 40 IU and 64 IU, respectively. The annual seroconversion rate was 0.8% in pregnant women, against 0.2% amongst non-immune blood donors over 3 months. In conclusion, our findings confirm the general prevalence of 50% of toxoplasmosis and an annual seroconversion rate of 0.8% in these two populations.

Multicenter evaluation of a new commercial assay for detection of immunoglobulin M antibodies to Toxoplasma gondii. Multicenter Study Group.

A new commercial assay for detection of IgM-specific antibodies to Toxoplasma gondii (IMx Toxo IgM, Abbott, USA), based on microparticle enzyme immunoassay technology, was evaluated at 15 clinical sites in Europe and the USA. Performance characteristics were established by testing clinical specimens collected randomly from pregnant women, blood donors, individuals with suspected Toxoplasma gondii infection and individuals confirmed HIV positive. Reference testing was performed using Toxo-M EIA (Abbott). Specimens evaluated at European sites yielding discordant results between the new assay and the reference EIA were further tested with an immunosorbent agglutination assay; at sites in the USA, discordant results were resolved using Platelia Toxo IgM (Sanofi, France) and Vidas Toxo IgM (bioMérieux, France) assays. In addition, matched plasma and serum, heat-treated and non-heat-treated specimens, and fresh and frozen specimens were evaluated at the USA sites. At European sites the new commercial assay had a sensitivity of 95.6% (196/205), a specificity of 99.8% (3,137/3,143) and an agreement of 99.6% (3,333/3,348) following resolution of discordant results; sensitivity in the USA was 97.4% (184/189), specificity was 99.8% (1,204/1,207) and agreement was 99.4% (1,388/1,396) following resolution. The new IMx Toxo IgM is a sensitive and specific assay for measurement of IgM antibodies to Toxoplasma gondii in human serum and plasma.

[Validation and clinical and epidemiological use of a serologic test recommended in the diagnosis of Helicobacter pylori infection]. / Validation et usage clinique et épidémiologique d'un test sérologique commercialsié dans le diagnostic de l'infection à Helicobacter pylori.

A commercial serologic test using purified antigens of Helicobacter pylori has been evaluated in the diagnosis of this infection. In a series of 250 patients undergoing endoscopy with antral biopsies for cytology, histology and culture, serology was positive in 68 of 71 patients with a positive culture (sensitivity: 96%) and negative in 67 of 69 patients with a normal mucosa and no microorganisms on biopsy (specificity: 97%). In the entire series, serology was positive in 33 patients with no infection on biopsies (13%). In a group of 205 blood donors, we confirmed an increasing prevalence with age, ranging from 13% in subjects less than 30 years old to 38% in subjects more than 60 years old.