Francesca Bellomi

Fate of neutralizing and binding antibodies to IFN beta in MS patients treated with IFN beta for 6 years

An increasing number of evidence is showing that during prolonged treatment of relapsing-remitting multiple sclerosis (RRMS) with interferon (IFN) beta 1a or IFN beta 1b, the patients may develop serum anti-IFN antibody. It has been argued that some of the RRMS patients receiving IFN beta, who developed antibodies to IFN, lose them over time even though the treatment continues. To gain further insights into this issue, we performed a study to establish what happened to binding antibodies (BAB) and neutralizing antibodies (NAB) in 42 RRMS patients treated for 6 years with IFN beta 1a and/or IFN beta 1b. While the data of BAB analysis did not allow to reach definite conclusions, the results on NAB development confirm that the presence of this type of antibodies is transitory; in fact, most of the positive patients reverted to seronegative, although the IFN treatment is still ongoing; the only patients who were positive for NAB at 6 years of treatment are those whose serum contains high concentration of them. The paper also shows that patients lose antibodies to IFN independently on the type of IFN used for the treatment. In conclusion, the data indicate that the disappearance of the anti-IFN antibodies from the serum while the patients are still undergoing IFN treatment depends on the titer of antibodies but not on the type of IFN administered.

Neutralizing and Binding Antibodies to IFN-β: Relative Frequency in Relapsing-Remitting Multiple Sclerosis Patients Treated with Different IFN-β Preparations

The frequencies of anti-interferon-β (IFN-β) antibody development reported to date in patients treated with different IFN-β preparations are not readily comparable mainly because of differences in ...

Neutralizing antibodies explain the poor clinical response to Interferon beta in a small proportion of patients with Multiple Sclerosis: a retrospective study

BackgroundNeutralizing antibodies (NAbs) against Interferon beta (IFNβ) are reported to be associated with poor clinical response to therapy in multiple sclerosis (MS) patients. We aimed to quantify the contribution of NAbs to the sub-optimal response of IFNβ treatment.MethodsWe studied the prevalence of NAbs in MS patients grouped according to their clinical response to IFNβ during the treatment period. Patients were classified as: group A, developing ≥ 1 relapse after the first 6 months of therapy; group B, exhibiting confirmed disability progression after the first 6 months of therapy, with or without superimposed relapses; group C, presenting a stable disease course during therapy. A cytopathic effect assay tested the presence of NAbs in a cohort of ambulatory MS patients treated with one of the available IFNβ formulations for at least one year. NAbs positivity was defined as NAbs titre ≥ 20 TRU.ResultsSeventeen patients (12.1%) were NAbs positive. NAbs positivity correlated with poorer clinical response (p < 0.04). As expected, the prevalence of NAbs was significantly lower in Group C (2.1%) than in Group A (17.0%) and Group B (17.0%). However, in the groups of patients with a poor clinical response (A, B), NAbs positivity was found only in a small proportion of patients.ConclusionThe majority of patients with poor clinical response are NAbs negative suggesting that NAbs explains only partially the sub-optimal response to IFNβ.

A one-year study on the pharmacodynamic profile of interferon-β1a 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.

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.

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 (β2mg) 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, β2mg 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.

Serum Interferon (IFN)-Neutralizing Antibodies and Bioactivities of IFNs in Patients with Severe Type II Essential Mixed Cryoglobulinemia

ABSTRACT The efficacy of alpha interferon (IFN-α) in the treatment of severe type II essential mixed cryoglobulinemia (EMC) has been reported previously. In some patients, the development of neutralizing antibodies to recombinant IFN-α (rIFN-α) can affect the clinical response achieved with rIFN-α; a second treatment with natural IFN-α preparations may reinduce the clinical response. In the present study the ability of leukocyte IFN (LeIFN) to restore the response was investigated from a pharmacodynamic viewpoint. Specifically, the pharmacodynamic profiles of different IFN-α preparations were studied by measuring the serum neopterin levels and the levels of expression of protein MxA mRNA in in vivo peripheral blood mononuclear cells in two patients with EMC whose resistance to rIFN-α2a treatment increased concomitantly with the development of neutralizing antibodies. These markers were measured before injection and at 24 and 48 h after a single injection of rIFN-α2a, consensus IFN [(C)IFN], or LeIFN. No increase or only a slight increase in MxA mRNA levels was detectable after administration of rIFN-α2a or (C)IFN, whereas a significant increase (≥10-fold) in MxA mRNA expression was recorded following administration of LeIFN. The neutralizing antibodies to rIFN-α2a cross-react with (C)IFN. Sera from these patients neutralized most but not all of the subtypes present in the natural IFN-α (LeIFN) mixture, and no significant increase in neopterin levels was observed after these patients were switched to LeIFN treatment. In summary, the data demonstrate that the problem of neutralizing antibodies still exists and that LeIFN may induce an increase in the level of MxA mRNA expression but not an increase in neopterin levels in patients who are resistant to treatment with rIFN-α2a or (C)IFN.

Proteolytic balance in patients with multiple sclerosis during interferon treatment

Multiple sclerosis (MS) is a progressive, inflammatory, demyelinating disease. An altered cytokine network has been reported to occur during the disease, and its pathogenetic role has been hypothesized. To date, interferon-beta (IFN-beta) is the most effective and reliable therapy in the majority of MS patients, although the mechanisms underlying its therapeutic effects are not fully understood. Breakdown of the blood-brain barrier (BBB) with consequent extravasation of the T cells and their invasion of the brain parenchyma seems to be one of the most important steps in the pathogenesis of the disease. Matrix metalloproteinease-2 (MMP-2) and MMP-9 are enzymes with proteolytic activities toward extracellular matrix ECM components. They are physiologically balanced by the MMP tissue inhibitors TIMP-2 and TIMP-1, so that proteolysis occurs as the result of increased MMP or decreased TIMP levels. In 38 patients with MS, MMP-2 and TIMP-1 levels were similar before and after 9 months of IFN-beta therapy, whereas MMP-9 levels significantly decreased and TIMP-2 levels significantly increased in comparison to values obtained before treatment. These results suggest that IFN-beta modulates T cell activities, including MMP and TIMP production, thus contributing either to maintaining the integrity of the BBB or to slowing the progression of the disease.

Neutralizing and Binding Antibodies to Interferon Beta in Patients with Multiple Sclerosis: A Comparison of Assay Results from Three Italian Centres

Abstract Interferon (IFN) beta therapy for multiple sclerosis (MS) is associated with the development of binding antibodies (BAbs) and neutralizing antibodies (NAbs) in a percentage of patients. This study investigated the reproducibility of results of two different antibody detection techniques using serum from 100 patients with MS who were receiving IFN beta therapy. Fifty samples were analysed using a commercially available kit-based BAb assay and a further 50 different samples were analysed using a widely used NAb cytopathic effect assay, at three different laboratories. All three centres agreed on the BAb status of all serum samples. However, only 84% agreement was reached on serum NAb status, and there was significant inter-laboratory variation in NAb titre values. Further analysis of these data revealed a correlation between the mean NAb titre and the coefficient of variation of serum samples, indicating greater discordance with higher NAb titres. A significant interlaboratory variation in NAb titres does exist; thus, caution is required when comparing titres from different centres. It is clear that validated detection assays are needed to accurately quantify NAb titres.

P-Glycoprotein Expression by Peripheral Blood Mononuclear Cells from Human Immunodeficiency Virus-Infected Patients Is Independent from Response to Highly Active Antiretroviral Therapy

During the last few years, highly active antiretroviral therapy has considerably reduced human immunodeficiency virus (HIV) disease progression (11). However, the treatment outcome is not always satisfactory (7). This can depend on different virological, immunological, behavioral, or pharmacological factors (5). In the framework of aspects, the interaction between P-glycoprotein (P-gp) and antiretroviral drugs has been evidenced (8, 13, 15). P-gp is a transmembrane phosphoglycoprotein belonging to the ATP-binding cassette superfamily that is able to transport several substrates through the cell membrane acting as a cationic pump (2, 3, 4, 6, 9, 14). Specifically, studies on protease inhibitors (PI) have evidenced that the transporter activity of P-gp may contribute to the reduced bioavailability of these drugs, which can act as substrates for P-gp (4, 15, 16). However, the influence of HIV infection on P-gp expression is still a matter of debate (1, 9), and as yet, no data are available on the effects of highly active antiretroviral therapy on its expression.