More MS news articles for Nov 2001

Evaluation of bioavailability of three types of IFN in multiple sclerosis patients by a new quantitative-competitive-PCR method for MxA quantification

Journal of Immunological Methods, Vol. 256 (1-2) (2001) pp. 141-152
PII: S0022-1759(01)00434-3
Antonio Bertolotto * NSGLB@TIN.IT , Francesca Gilli, Arianna Sala, Luisa Audano, Anna Castello, Umberto Magliola, Fabio Melis and Maria Teresa Giordana
Centro Sclerosi Multipla and Laboratorio di Neurobiologia Clinica, Divisione Universitaria di Neurologia, Azienda Ospedaliera S. Luigi, Università di Torino, Regione Gonzole 10, 10043 Orbassano, Italy


Intracellular expression of human myxovirus protein A (MxA) is exclusively induced by type I IFNs (IFNa,b,w) or by some viruses and it is strongly increased under IFN treatment.

We set up an internally controlled quantitative-competitive polymerase chain reaction (qc-PCR) that quantifies MxA mRNA expressed in human peripheral blood mononuclear cells (PBMC).

Our qc-PCR is accurate because the mean ratio of copy number estimated by qc-PCR to that quantified spectrophotometrically is 1.08±0.03, moreover it is repeatable with high sensitivity (1 fg MxA/pg GAPDH).

MxA mRNA was tested in 47 Relapsing-Remitting Multiple Sclerosis (RR-MS) untreated patients and in 48 patients treated with one of the 3 IFNb licensed for MS (24 with Rebif, 14 with Avonex and 10 with Betaferon). All the 48 treated patients were negative to IFNb neutralising antibodies (NABs) as tested in our laboratory using a cytopatic assay (CPE).

MxA mRNA levels were detectable in all untreated patients (mean 24±18 fg MxA/pg GAPDH) and significantly higher levels were found in all the treated patients 12 h after IFNb administration (mean 499±325 fg MxA/pg GAPDH); furthermore, the three types of IFNb showed comparable bioavailability.

Our data indicate that the bioavailability of the three available types of IFNb can be evaluated by MxA qc-PCR.


IFN, interferon;
MxA, mixovirus resistance protein A;
GAPDH, glyceraldeide-3-phosphate-dehydrogenase;
co-MxA, MxA competitor;
co-GAPDH, GAPDH competitor;
qc-PCR, quantitative competitive polymerase chain reaction;
PBMC, peripheral blood mononuclear cells;
MS, multiple sclerosis;
NABs, neutralising antibodies;
Et-Br, ethidium bromide;
RT, retro-transcription;
PBS, phosphate buffered saline

*Corresponding author. Tel.: +39-11-9026397; fax: +39-11-9026397

© 2001 Elsevier Science B.V.