Monique Bodéus

Early signs and risk factors for the increased incidence of Epstein-Barr virus-related posttransplant lymphoproliferative diseases in pediatric liver transplant recipients treated with tacrolimus.

BACKGROUND Posttransplant lymphoproliferative disease (PTLD) is a life-threatening condition the incidence of which in pediatric solid organ transplantation may be related to the immunosuppressive load. It has been suggested that tacrolimus, a new and potent immunosuppressor, causes an increased incidence of this syndrome. METHODS The incidence, early signs, and risk factors for lymphoproliferative disease were reviewed in a cohort of 89 pediatric liver transplant recipients treated with tacrolimus. RESULTS Eighteen patients (20%) developed a PTLD-16 concomitant to a primary Epstein-Barr virus (EBV) infection and 2 with previous immunity against EBV. Three additional patients had preliminary signs of PTLD concomitant to primary EBV infection, but did not develop individualized lymphoid masses. Six patients died (6.7% of all tacrolimus-treated patients). Mean tacrolimus blood level during the 3 months preceding EBV infection reached 11.8+/-1.8 ng/ml in PTLD patients versus 9.4+/-3.4 ng/ml in non-PTLD patients (0.05<P<0.1). Previous OKT3 or antithymocyte globulin treatment was also significantly associated to PTLD. There was no association with age, rejection episodes, steroid-resistant rejection, prior cytomegalovirus infection, HLA mismatch, living donor or cadaveric organ transplantation, United Network for Organ Sharing status at the time of orthotopic liver transplant, and primary or rescue tacrolimus treatment. A significant increase of total gamma-globulin level occurred in PTLD patients, and mono/oligoclonal production was significantly associated to PTLD. CONCLUSION In EBV-infected pediatric liver transplant recipients, use of OKT3 or antithymocyte globulin and high tacrolimus blood levels are risk factors for a significant increase in the incidence of PTLD. An increase in total gamma-globulin level and appearance of mono/oligoclonal immunoglobulin production are the major preliminary signs of the syndrome.

Prenatal diagnosis of human cytomegalovirus by culture and polymerase chain reaction: 98 pregnancies leading to congenital infection

Human cytomegalovirus (HCMV) is the most common cause of viral intra‐uterine infection. The experience with prenatal diagnosis remains limited and is based on few reports of small numbers of cases. It is thus difficult to compare the accuracy of the different tests because the groups studied were small and heterogeneous. We describe here our experience on a series of 98 pregnancies leading to HCMV congenital infection, among which 71 have been tested by amniotic fluid (AF) sampling followed by culture and/or polymerase chain reaction (PCR). Independently of the delay between AF sampling and the first HCMV IgM positive result, the mean sensitivity of both culture and PCR was around 70 per cent. The best sensitivity (95.5 per cent) was obtained after a delay ⩾6 weeks in late pregnancy (⩾23 weeks). The present study demonstrated clearly that the delay between AF puncture and the presumed date of seroconversion is more important for sensitivity than the technique used for the diagnosis (PCR or culture). However, even in the best diagnostic conditions, negative results of HCMV culture or PCR in AF cannot formally exclude intra‐uterine infection. Copyright

Avidity of IgG antibodies distinguishes primary from non-primary cytomegalovirus infection in pregnant women.

BACKGROUND Human cytomegalovirus (HCMV) is the most common cause of viral intrauterine infection. Fetal damage is mostly linked to maternal primary infection. It is therefore important to differentiate primary from non-primary infection in pregnant females. IgM tests often used for this purpose are not reliable enough. OBJECTIVE To evaluate an HCMV-IgG urea-elution assay for its ability to distinguish primary from non-primary infection. In this assay, soaking the antigen-antibody complex with an urea containing solution frees antibodies with low avidity but has no influence on those with high avidity. An avidity index (AI) was calculated: AI = (OD with urea/OD without urea) x 100. STUDY DESIGN HCMV-IgG avidity was measured on a single serum of 79 patients with past infection (pregnant women, graft recipients and blood donors) and of 63 patients (78 sera) with documented seroconversion (pregnant women and graft recipients). Sixty-one pregnant women positive or equivocal for HCMV-IgM but without a documented seroconversion were included in this study. RESULTS Most (72/79) of the patients with past infection had an AI > 65% and all but one had an AI > 50%. In pregnant women, in the case of a primary infection within the past 3 months, AI are usually (51/53) < 50% and never > 65%. Among the IgM positive pregnant women who lack a seroconversion history, 38 had AI > 65% suggestive of an infection that had occurred at least 3 months earlier, 11 had an AI in a grey area between 50 and 65% and 12 had an AI < 50%, suggestive of a recent primary infection. CONCLUSIONS In pregnant women, measurement of the IgG avidity may help to date a HCMV infection, an AI > 65% highly suggests a past infection while an AI < 50% corresponds to a recent primary infection.

Increased risk of cytomegalovirus transmission in utero during late gestation

OBJECTIVE To determine whether the rate of human cytomegalovirus transmission in utero is related to the gestational age at the time of maternal infection. METHODS One hundred twenty-three pregnant women followed in our units between 1988 and 1998 were studied retrospectively. Each had developed a primary infection with cytomegalovirus evidenced by a seroconversion, confirmed by specific enzyme immunoassays. Infants were diagnosed by urine culture. RESULTS Regardless of gestational age at the time of maternal cytomegalovirus seroconversion, the mean rate of intrauterine transmission was 57.5%. There was a statistically significant difference between early seroconversion (during the first trimester) and late seroconversion (during the third trimester) (36.0% versus 77.6%; P < .001). The risk of transmission calculated for seroconversion during the second trimester was intermediate (44.9%). CONCLUSION A statistically significant difference in the rate of intrauterine cytomegalovirus transmission was observed according to the duration of pregnancy at which primary infection occurred. The rate of transmission increased with gestational age.

Characteristics of Epstein-Barr virus primary infection in pediatric liver transplant recipients.

BACKGROUND/AIM: Pediatric liver transplant recipients are at high risk of Epstein-Barr virus infection. However the incidence of clinical symptoms and the graft function at the time of acute infection remains poorly documented. The aim of this study was to monitor the clinical and biochemical events associated with primary Epstein-Barr virus infection. METHODS: Clinical and biological patterns associated with Epstein-Barr virus infection were prospectively searched in 38 liver transplanted children. Polymerase chain reaction and anti-Epstein-Barr virus IgM antibodies were used at regular intervals to detect the timing of primary infection. RESULTS: Five children (13%) had pretransplant immunity, 26 (68.5%) developed primary Epstein-Barr virus infection 15 to 90 days after transplantation and seven (18.5%) remained Epstein-Barr virus negative. The four patients with clinical symptoms at the time of infection subsequently developed post-transplant lymphoproliferative disease. A single post-transplant lymphoproliferative disease occurred in non-symptomatic patients (overall incidence 13%). No mortality was associated with post-transplant lymphoproliferative disease. Two asymptomatic patients had abnormal liver function tests possibly related to primary Epstein-Barr virus infection. CONCLUSION: Epstein-Barr virus primary infection occurs in 80% of seronegative patients within 3 months after OLT. Clinical symptoms are rare and closely associated with post-transplant lymphoproliferative disease. Outside post-transplant lymphoproliferative disease, the consequences of infection are marginal.

The seroepidemiology of human T-lymphotropic viruses: Types I and II in Europe: A prospective study of pregnant women

Background: Up to 20 million persons are infected with the human retroviruses human T-lymphotropic virus (HTLV)-I and HTLV-II globally. Most data on the seroprevalence of HTLV-I and HTLV-II in Europe are from studies of low-risk blood donors or high-risk injection drug users (IDUs). Little is known about the general population. Methods: A prospective anonymous study of HTLV-I and HTLV-II seroprevalence among 234,078 pregnant women in Belgium, France, Germany, Italy, Portugal, Spain, and the United Kingdom was conducted. Maternal antibody status was determined by standard methods using sera obtained for routine antenatal infection screens or eluted from infant heel prick dried blood spots obtained for routine neonatal metabolic screens. Results: Anti-HTLV-I/II antibodies were detected and confirmed in 96 pregnant women (4.4 per 10,000, 95% confidence interval [CI]: 3.5-5.2). Of these, 73 were anti-HTLV-I, 17 were anti-HTLV-II, and 6 were specifically anti-HTLV but untyped. The seroprevalence ranged from 0.7 per 10,000 in Germany to 11.5 per 10,000 in France. Conclusions: Pregnant women better reflect the general population than blood donors or IDUs. The seroprevalence of HTLV-I and HTLV-II in Western Europe is 6-fold higher among pregnant women (4.4 per 10,000) than among blood donors (0.07 per 10,000). These data provide a robust baseline against which changes in HTLV-I and HTLV-II seroprevalence in Europe can be measured.

In vitro binding and phosphorylation of human immunodeficiency virus type 1 Nef protein by serine/threonine protein kinase

Although the human immunodeficiency virus type 1 (HIV-1) nef gene still has no precisely defined function, in vivo studies have demonstrated that Nef is an important pathogenic determinant of HIV. In order to identify cellular proteins capable of binding to Nef, the HIV-1LAI nef gene product was expressed in the bacterial vector pGEX-2T as a glutathione S-transferase (GST)-Nef fusion protein. Deletion mutants corresponding to 86 and 35 N-terminal residues of the Nef protein were prepared. The GST-Nef constructs were used to identify cellular kinases capable of interacting with Nef. After incubation with a Jurkat cell lysate, the GST-Nef constructs immobilized on glutathione-agarose beads bound to cellular kinase(s) and were phosphorylated at three sites in vitro: one on threonine at position 15, one on serine between residues 1 and 35, and one on threonine between residues 36 and 86. The Nef-phosphorylating activity was inhibited by protein kinase C (PKC)-selective inhibitors. Cell fractionation showed that this Nef-binding kinase was mainly in the membrane-associated fraction. These results suggest that kinase(s) of the PKC family are specifically bound to and phosphorylate Nef in vitro. The interaction of Nef with cellular kinases and its phosphorylation may be important in mediating the effects of Nef in HIV-1 pathogenesis.

Evaluation of the New Architect Cytomegalovirus Immunoglobulin M (IgM), IgG, and IgG Avidity Assays

ABSTRACT A panel of new cytomegalovirus (CMV) assays for use on the Architect instrument has been developed, including a CMV avidity assay based on a new technology. The purpose of this study was to compare the performance characteristics of the fully automated CMV immunoglobulin M (IgM), IgG, and IgG avidity tests on the Architect instrument with those of other available assays. A total of 503 consecutive fresh patient serum specimens (routine serum specimens) and 96 serum specimens from 33 pregnant women with a recent CMV primary infection (seroconversion serum specimens) were tested for CMV IgM and IgG by the Architect (Abbott), Vidas (BioMérieux), and Enzygnost (Siemens) assays. The seroconversion sera and 100 preselected serum specimens IgM negative and IgG positive by the AxSYM assay were also tested by the IgG avidity tests on the Architect and Vidas instruments. The relative agreements for CMV IgM determination with routine sera between the Architect assay and the Vidas, Enzygnost, and AxSYM assays were 97%, 94%, and 93%, respectively, for the CMV IgM tests and 99%, 98%, and 98%, respectively, for the CMV IgG tests. The specificities of the CMV IgG avidity test were 98% for the Architect assay and 76% for the Vidas assay. No high CMV IgG avidity test results were found within the first 3 months after seroconversion by either of those assays. The correlation between the results of the newly developed CMV IgM and IgG tests on the Architect instrument with the Vidas and Enzygnost assays was excellent (≥94%). The CMV IgG avidity test reliably excluded patients with recent infections and showed an excellent specificity (98%).

Predictive value of maternal-IgG avidity for congenital human cytomegalovirus infection.

BACKGROUND Human cytomegalovirus (HCMV) is now the most common cause of viral intrauterine infection. Fetal damage is mostly linked to maternal primary infection. It is therefore important to differentiate primary from recurrent or persistent HCMV infection in pregnant females. For this purpose, IgM tests are not reliable enough and the measurement of the IgG avidity appears to be presently the best method. OBJECTIVE To evaluate the performance of the measurement of HCMV-IgG avidity by a 8 M urea denaturation assay in predicting congenital infection in the offspring. STUDY DESIGN Seventy-eight women were included in this study on the basis of a HCMV IgM positive or equivocal result on a first serum during pregnancy, but without a documented seroconversion history. The IgG avidity was measured and correlated with the outcome of the pregnancy. RESULTS In eight cases of HCMV in utero infection the maternal HCMV-IgG avidity index was below 50%. One case of HCMV in utero infection was observed despite a high avidity index during the second trimester of the pregnancy. High or intermediate HCMV-IgG avidity indexes during the first trimester of pregnancy were not associated with a congenital infection. CONCLUSIONS Even in the presence of an IgM positive result, an HCMV IgG avidity index above 65% on a serum obtained during the first trimester of pregnancy could reasonably be considered as a good indicator of past HCMV infection. In these conditions invasive prenatal diagnosis is not necessary.

False-positive IgM antibody tests for cytomegalovirus in patients with acute Epstein-Barr virus infection.

Abstract The diagnosis of acute cytomegalovirus (CMV) infection is frequently based on a positive IgM result. False-positive reactions due to interfering infections may exist. Between August 1998 and May 1999, 62 patients were found to be IgM positive and IgG negative with the Axsym assay (Abbott, Germany). Serological testing for Epstein-Barr virus (EBV) was performed in these patients to detect any cross-reactivity due to acute mononucleosis. Additionally, the results of the CMV Axsym was evaluated in 40 patients with acute EBV infection. The results suggest that the CMV-IgM Axsym assay shows a lack of specificity due to acute EBV infection. Precautions must be taken when CMV-IgM Axsym results are interpreted. It seems necessary to confirm equivocal results with another technique and to take into account other clinical and biological observations.