Measurement of the sensitivity of different commercial assays in the diagnosis of CMV infection in pregnancy

To evaluate the performance of different commercial assays for the detection of recent cytomegalovirus (CMV) in pregnancy, the sensitivity and specificity of assays for CMV-specific IgM antibodies were compared. Routine specimens from pregnant women were screened for CMV IgM using the Abbott AxSYM assay. Sera that were reactive according to AxSYM were further tested for IgM by other commercial assays. In selected IgM positive samples a CMV IgG avidity assay (Radim) and virus isolation from urine (shell vial) were also performed. The positivity rate for IgM anti-CMV by AxSYM was relatively high (140 out of 492, combining reactive and grayzone results). Only 26 of the 140 samples were positive for IgM according to Radim. The IgG avidity was low in 16 of the 43 samples tested, and the Radim and DiaSorin IgM assays were negative in 5 of them; 2 of the latter cases were also positive for viral isolation according to a shell vial method. There are differences in the sensitivity of the commercially available tests for CMV antibodies. CMV screening in pregnancy is performed as a first step by immunoassays and the choice of highly sensitive IgM test associated with further serological and virological methods could help to identify early primary infections.

Pharmacodynamics of peginterferon alpha-2a and peginterferon alpha-2b in interferon-naïve patients with chronic hepatitis C: a randomized, controlled study

BACKGROUND

Peginterferon alpha-2a and alpha-2b, the two commercially available pegylated interferons, have different pharmacokinetic properties that produce differing abilities to suppress replication of the hepatitis C virus.

AIM

To compare the pharmacodynamics of peginterferon alpha-2a and peginterferon alpha-2b in interferon-naive patients with chronic hepatitis C.

METHODS

Patients were randomized to receive peginterferon alpha-2a, 180 microg (n = 10) or peginterferon alpha-2b 1.0 microg/kg (n = 12) once weekly. The enzymatic activity of 2'5'-oligoadenylate synthetase and levels of neopterin and beta(2)-microglobulin were measured at baseline and at 24, 48, 120 and 168 h.

RESULTS

Oligoadenylate synthetase activity and serum neopterin and beta(2)-microglobulin concentrations did not differ significantly between the two patient groups at any time point, nor was there a significant correlation between the serum area under the concentration-time curve of either peginterferon and the area under the concentration-time curve for 2',5'-oligoadenylate synthetase, neopterin and beta(2)-microglobulin. The area under the concentration-time curves calculated for these three markers did not correlate with body mass index stratified at <25 and >or=25 kg/m(2) for either peginterferon.

CONCLUSIONS

Despite pharmacokinetic differences between peginterferon alpha-2a and peginterferon alpha-2b, the pharmacodynamic profiles of the two formulations appear to be comparable.

Expression of biomarkers of interferon type I in patients suffering from chronic diseases

Interferons (IFNs) are used widely in the treatment of viral infections, tumours and neurological disorders. The aim of this study was to evaluate the endogenous expressions of various IFN-induced compounds [specifically: neopterin (NPT), beta2microglobulin (beta2mg) and 2-5 oligoadenylate synthetase (2-5 OAS)] in patients with various chronic diseases requiring treatment with IFN type I. The results showed that patients with such chronic diseases as hepatitis C virus-associated type II mixed cryoglobulinaemia (MC), chronic hepatitis C (CHC) and relapsing-remitting multiple sclerosis (RRMS) are characterized by different activations of the IFN system. Furthermore, the interindividual variability in baseline levels of IFN-induced biomarkers was higher in patients with chronic diseases than in healthy individuals. When levels of the above biomarkers were measured 24 h after the first injection of IFN in patients with CHC or RRMS, significant increases in expression levels of IFN-induced compounds were recorded but, again, there is a broad range of variability in the degree of increase. Further, a significant inverse correlation between baseline levels of NPT, beta2mg and 2-5 OAS activity and their relative increases after IFN administration was found in patients with CHC or RRMS. Together, the results are consistent with the observation that there is considerable interindividual heterogeneity in the clinical response to IFNs, which suggests that host factors other than disease markers must be taken into account in order to manage and optimize the IFN therapy.

P-glycoprotein expression affects the intracellular concentration and antiviral activity of the protease inhibitor saquinavir in a T cell line

A number of ATP-binding cassette proteins, which function as cellular efflux pumps, are known to be expressed on the membranes of human cells, including CD4-positive lymphocytes. It has also been shown recently that most anti-HIV protease inhibitors (PIs) are first-rate substrates of one of these membrane transporters, P-glycoprotein (Pgp). These findings raise the question of whether Pgp expression could influence HIV replication and/or affect the action of PIs. To gain new insight into this, initially unexpected, phenomenon, a study was undertaken with the aims of investigating whether treatment with saquinavir (SQV) induces Pgp expression in primary or transformed human T cell lines and, primarily, establishing whether Pgp expression could modify both the uptake of SQV and its antiviral action. Pgp expression, mainly measured by reverse transcription-PCR, was found to be variably detectable in healthy individuals, and short or prolonged SQV treatment was unable to induce or increase the expression of Pgp in a lymphoblastoid cell line or in primary lymphocytes derived from these individuals. However, further experiments, performed in a cell line with high Pgp expression (CEM(VBL100) cells) and its parental cell line (CEM cells), demonstrated that over-expression of Pgp reduces the uptake of SQV This result is consistent with the finding that CEM(VBL100) cells are less sensitive to the antiviral activity of SQV, the ID50 value (100 microM) being significantly higher than the corresponding value in parental CEM cells (4 microM).

A one-year study on the pharmacodynamic profile of interferon-beta1a in MS

Interferon (IFN)-beta1a induction of neopterin and beta2-microglobulin (beta2-MG) were evaluated over 1 year in patients with MS. Neopterin and beta2-MG levels peaked 24 to 48 hours after weekly injections of IFNbeta1a over the entire study period. Predose levels of neopterin decreased significantly, consistent with a long-term decrease in IFNgamma expression and macrophage activation during IFNbeta-1a treatment. Predose levels of beta2-MG increased, the significance of which is as yet unclear.