Genetic diversity and its impact on disease severity in respiratory syncytial virus subtype-A and -B bronchiolitis before and after pandemic restrictions in Rome.

OBJECTIVES: To scrutinize whether the high circulation of respiratory syncytial virus (RSV) observed in 2021-2022 and 2022-2023 was due to viral diversity, we characterized RSV-A and -B strains causing bronchiolitis in Rome, before and after the COVID-19 pandemic. METHODS: RSV-positive samples, prospectively collected from infants hospitalized for bronchiolitis from 2017-2018 to 2022-2023, were sequenced in the G gene; phylogenetic results and amino acid substitutions were analyzed. Subtype-specific data were compared among seasons. RESULTS: Predominance of RSV-A and -B alternated in the pre-pandemic seasons; RSV-A dominated in 2021-2022 whereas RSV-B was predominant in 2022-2023. RSV-A sequences were ON1 genotype but quite distant from the ancestor; two divergent clades included sequences from pre- and post-pandemic seasons. Nearly all RSV-B were BA10 genotype; a divergent clade included only strains from 2021-2022 to 2022-2023. RSV-A cases had lower need of O2 therapy and of intensive care during 2021-2022 with respect to all other seasons. RSV-B infected infants were more frequently admitted to intensive care units and needed O2 in 2022-2023. CONCLUSIONS: The intense RSV peak in 2021-2022, driven by RSV-A phylogenetically related to pre-pandemic strains is attributable to the immune debt created by pandemic restrictions. The RSV-B genetic divergence observed in post-pandemic strains may have increased the RSV-B specific immune debt, being a possible contributor to bronchiolitis severity in 2022-2023.

Frequent detection of high human papillomavirus DNA loads in oral potentially malignant disorders.

Human papillomavirus (HPV) is estimated to be the cause of 40--80% of the squamous cell carcinoma of the oropharynx but only of a small fraction of the oral cavity cancers. The prevalence of oral HPV infection has significantly increased in the last decade, raising concerns about the role of HPV in progression of oral potentially malignant disorders (OPMD) toward squamous cell carcinomas. We sought to study HPV infection in patients with oral lesions, and in control individuals, using non-invasive and site-specific oral brushing and sensitive molecular methods. HPV DNA positivity and viral loads were evaluated in relation to patient data and clinical diagnosis. We enrolled 116 individuals attending Dental Clinics: 62 patients with benign oral lesions (e.g. fibromas, papillomatosis, ulcers) or OPMD (e.g. lichen, leukoplakia) and 54 controls. Oral cells were collected with Cytobrush and HPV-DNA was detected with quantitative real-time PCR for the more common high-risk (HR) and low-risk (LR) genotypes. HPV detection rate, percentage of HR HPVs and HPV-DNA loads (namely HPV16 and in particular, HPV18) were significantly higher in patients than in controls. Lichen planus cases had the highest HPV-positive rate (75.0%), hairy leukoplakia the lowest (33.3%). This study detected unexpectedly high rates of HPV infection in cells of the oral mucosa. The elevated HR HPV loads found in OPMD suggest the effectiveness of quantitative PCR in testing oral lesions. Prospective studies are needed to establish whether elevated viral loads represent a clinically useful marker of the risk of malignant progression.

Hepatitis C virus and interferon type III (interferon-λ3/interleukin-28B and interferon-λ4): genetic basis of susceptibility to infection and response to antiviral treatment.

There has been a significant increase in our understanding of the host genetic determinants of susceptibility to viral infections in recent years. Recently, two single-nucleotide polymorphisms (SNPs), rs12979860 T/C and rs8099917 T/G, upstream of the interleukin (IL)-28B/interferon (IFN)-λ3 gene have been clearly associated with spontaneous and treatment-induced viral clearance in hepatitis C virus (HCV) infection. Because of their power in predicting the response to IFN/ribavirin therapy, the above SNPs have been used as a diagnostic tool, even though their relevance in the management of HCV infection will be blunt in the era of IFN-free regimens. The recent discovery of a new genetic variant, ss469415590 TT/ΔG, upstream of the IL-28B gene, which generates the novel IFN-λ4 protein, has opened up a new and alternative scenario to understand the functional architecture of type III IFN genomic regions and to improve our knowledge of the pathogenetic mechanism of HCV infection. A role of ss469415590 in predicting responsiveness to antiviral therapy has also been observed in HCV-infected patients receiving direct antiviral agents. The underlying biological mechanism that links the above IL-28B polymorphisms (in both IFN-λ3 and IFN-λ4) to spontaneous and treatment-induced clearance of HCV infection remains to be discovered. Despite this, shedding some light on this issue, which is the main aim of this review, may provide new insights into the general topic of 'host genetics and viral infections'.

Rapid spread of the novel respiratory syncytial virus A ON1 genotype, central Italy, 2011 to 2013.

Respiratory infections positive for human respiratory syncytial virus (RSV) subtype A were characterised in children admitted to hospitals in Rome and Ancona (Italy) over the last three epidemic seasons. Different strains of the novel RSV-A genotype ON1, first identified in Ontario (Canada) in December 2010, were detected for the first time in Italy in the following 2011/12 epidemic season. They bear an insertion of 24 amino acids in the G glycoprotein as well as amino acid changes likely to change antigenicity. By early 2013, ON1 strains had spread so efficiently that they had nearly replaced other RSV-A strains. Notably, the RSV peak in the 2012/13 epidemic season occurred earlier and, compared with the previous two seasons, influenza-like illnesses diagnoses were more frequent in younger children; bronchiolitis cases had a less severe clinical course. Nonetheless, the ON1-associated intensive care unit admission rate was similar, if not greater, than that attributable to other RSV-A strains. Improving RSV surveillance would allow timely understanding of the epidemiological and clinicopathological features of the novel RSV-A genotype.

Interleukin-28B (IL-28B) single-nucleotide polymorphisms and interferon plus ribavirin treatment outcome in Italian chronically HCV-infected patients.

To determine the single or combined effect of both rs12979860 and rs8099917 SNPs on HCV treatment response, these variants were genotyped in samples from a cohort of 170 patients infected with different HCV genotypes (HCVGT). The favourable rs12979860 CC genotype was found only in patients with sustained or rapid virological responses (SVR/RVR) and at significantly high proportions in HCVGT1/4 SVR patients. A significant association was also found between the rs8099917 TT genotype and SVR in both HCVGT1/4 and HCVGT2/3 groups of patients. In contrast, we found that there was significantly more of the rs8099917 GG genotype in nonresponders (NR) than in SVR patients which suggests a good association of the minor homozygote GG with the lack of treatment response. The combination of rs12979860/rs8099917 CC/TT favourable genotypes was found only in SVR patients and matched the frequency observed for their rs12979860 CC genotypes alone. By contrast, the inverse unfavourable correlate rs12979860/rs8099917 TT/GG genotype was seen more in NR than in SVR patients as observed for the single GG genotype. This study confirms the impact of both rs12979860 and/or rs8099917 IL-28B SNPs on treatment-induced clearance of HCV-RNA and demonstrates that the rs12979860 CC genotype is stronger than rs8099917 TT genotype in predicting a positive treatment response in HCVGT1/4 patients. The unfavourable rs8099917 GG genotype seems to be more important in predicting the failure of treatment response independently from HCV genotype.

Development and specificities of anti-interferon neutralizing antibodies in patients with chronic hepatitis C treated with pegylated interferon-α.

Only limited data are available on the development of neutralizing antibodies (NAB) in patients with chronic hepatitis C (CHC) treated with pegylated interferon-α (PEG-IFN-α). The aim of this study was to evaluate the immunogenicity of PEG-IFN-α when administered to CHC patients who had or had not previously received standard IFN-α therapy. In addition, the specificities of NAB, together with the ability of leucocyte (LE) -IFN-α to re-establish therapeutic responsiveness in NAB-positive patients, were evaluated. NAB were assessed using a quantitative, standardized, virus-induced cytopathic effect assay. The seroconversion rate to PEG-IFN-α was higher in patients who had received previous standard IFN-α treatment than in those treated exclusively with PEG-IFN-α. Also, NAB produced during PEG-IFN-α therapy were unable to neutralize LE-IFN-α entirely, even though they can neutralize several IFN-α subtypes. In addition, the results indicate that a change to LE-IFN-α therapy can be associated with restoration of clinical responses in NAB-positive patients who had become resistant after showing an initial response to PEG-IFN-α treatment. This study emphasizes the importance of evaluating NAB development in CHC patients who become resistant to PEG-IFN-α treatment, and suggests management alternatives for patients who develop NAB.

Virological and clinical characterization of respiratory infections in children attending an emergency department during the first autumn-winter circulation of pandemic A (H1N1) 2009 influenza virus.

To characterize respiratory virus infections during the first autumn-winter season of pandemic A (H1N1) 2009 influenza virus (A/H1N1/2009) circulation, a prospective study in children attending a paediatric emergency department at the Sapienza University hospital, Rome, was conducted from November 2009 to March 2010. By means of both nasal washings and pharyngeal swabs, enrolled children were checked for 14 respiratory viruses. The majority of acute respiratory infections resulted from viral pathogens (135/231, 58%). Overall, the most common was respiratory syncytial virus (RSV), in 64% of positive samples; A/H1N1/2009 was the only influenza virus found in 16% and rhinovirus (RV) in 15%. Virus-positive children did not differ significantly from virus-negative children in signs and symptoms at presentation; of the virus groups, RSV-infected children were younger and more frequently admitted to intensive-care units than those infected with A/H1N1/2009 and RV. Of the hospitalized children, stratified by age, both infants and children aged >1 year with RSV were most severely affected, whereas A/H1N1/2009 infections were the mildest overall, although with related pulmonary involvement in older children. Children with RV infections, detected in two flares partially overlapping with the A/H1N1/2009 and RSV peaks, presented with bronchiolitis, wheezing and pneumonia. Leukocytosis occurred more frequently in RV-infected and A/H1N1/2009-infected children, and numbers of blood eosinophils were significantly elevated in RV-infected infants. Given the fact that clinical and epidemiological criteria are not sufficient to identify viral respiratory infections, a timely virological diagnosis could allow different infections to be managed separately.

Rhinovirus bronchiolitis and recurrent wheezing: 1-year follow-up.

The association between bronchiolitis and recurrent wheezing remains controversial. In this prospective study, we assessed risk factors for recurrent wheezing during a 12-month follow-up in 313 infants aged <12 months hospitalised for their first episode of bronchiolitis. Demographic, clinical and laboratory data were obtained with a questionnaire and from medical files. A total of 14 respiratory viruses were concurrently assayed in nasal washings. Parents were interviewed 12 months after hospitalisation to check whether their infants experienced recurrent wheezing. The rate of recurrent wheezing was higher in infants with bronchiolitis than in controls (52.7 versus 10.3%; p<0.001). Multivariate analysis identified rhinovirus (RV) infection (OR 3.3, 95% CI 1.0-11.1) followed by a positive family history for asthma (OR 2.5, 95% CI 1.2-4.9) as major independent risk factors for recurrent wheezing. In conclusion, the virus most likely to be associated with recurrent wheezing at 12 months after initial bronchiolitis is RV, a viral agent that could predict infants prone to the development of recurrent wheezing.

Detection of respiratory viruses in the 2009 winter season in Rome: 2009 influenza A (H1N1) complications in children and concomitant type 1 diabetes onset.

We investigated clinical characteristics and complications, particularly type 1 diabetes onset, in children hospitalized for 2009 pandemic influenza A (H1N1) virus and compared number of consultations, rate of hospitalization and virus identification in children hospitalized for acute respiratory symptoms (ARS) during the winter season 2009-2010 and 2004-2005. Patients were tested for 2009 H1N1 virus and 14 respiratory viruses on pharyngeal brush/nasal aspirates, using a RT-PCR or nested PCR assays. Consultations and hospitalizations were extracted from operative system GIPSE. The total number of consultations increased by 12%, consultation rate for ARS by 13% and number of hospitalizations by 56% from 2004-2005 to 2009-2010. In 2004-2005, Influenza A virus was identified in only 7 percent of hospitalized children, while in 2009-2010 the 2009 H1N1 virus was identified in 21%. Three children attending the hospital for ARS and 2009 H1N1 infection had ketoacidosis as the onset manifestation of type 1 diabetes. By comparing the number of new diabetes diagnoses among the two winter seasons, we found a higher number of new diagnoses in October 2009-January 2010 than in the same period in 2004-2005 (19 vs 10). Six children (13%), all presenting with pre-existing diseases, were admitted to the pediatric intensive care unit. No children died. The outbreak of this novel virus has increased pediatric consultation rates and hospitalizations compared with previous winters without causing deaths. The children at highest risk for severe infection are those with comorbidities. The 2009 H1N1 virus seems in some way involved in the pathogenesis of type 1 diabetes.

Interferon-induced gene expression in cervical mucosa during human papillomavirus infection.

The aim of this study is to monitor type I interferon (IFN) activation in the cervical mucosa of Human Papillomavirus (HPV)-infected and uninfected women attending a routine gynaecologic clinic. The expression of three IFN-induced genes (MxA coding for human Mixovirus resistance protein A, ISG15 Interferon Stimulated Gene coding for a 15 kDa ubiquitin-like protein and UBP43 coding for the ISG15 isopeptidase) was determined as the mRNA copy number in cervical cells, normalized to the mRNA ones of the beta-glucuronidase gene. Type-specific HPV-DNA load was concurrently determined in the HPV-positive samples. Out of 127 samples tested, 54 were sufficient for both DNA and RNA extraction. The type-specific HPV-DNA copy numbers in the 34 HPV-positive samples varied widely. No significant association was found between copy numbers of MxA, ISG15, UBP43 and HPV status or viral load. However, despite a marked inter-individual variability, ISG15 expression was significantly higher when low-risk HPV infections were compared with HPV-negative samples, while high-risk HPV infections had very low ISG15 levels. The lack of ISG15 activation in high-risk HPV-infected cervical cells could be due to the lack of p53-mediated induction or to HPV-directed specific inhibition of type I IFN pathways. This study approach might be of value in clarifying the role of type I IFN activation in determining the clearance or persistence of HPV infections.

Virological diagnosis of respiratory virus infection in patients attending an emergency department during the influenza season.

To investigate the burden of influenza-like illness (ILI), patients attending an emergency department during the influenza season were tested for several common respiratory viruses, using PCR-based methods. Influenza A viruses were detected in 25 of 103 recruited patients (24%), rhinoviruses in 15%, and respiratory syncytial virus in only one. The data suggest that triage criteria based on ILI case definitions would not contain the spread of the influenza virus during pandemic alerts and could lead to unnecessary isolation of patients with other infections. Application of broader triage criteria followed by timely molecular diagnosis could be effective in preventing new respiratory agent transmission.

Respiratory syncytial virus, human bocavirus and rhinovirus bronchiolitis in infants.

OBJECTIVE: To investigate the prevalence of 14 viruses in infants with bronchiolitis and to study demographic and clinical differences in those with respiratory syncytial virus (RSV), human bocavirus (hBoV) and rhinovirus (RV) infection. METHODS: 182 infants aged <12 months hospitalised for bronchiolitis were enrolled. Infants underwent nasal washing for the detection of RSV, influenza virus A and B, human coronavirus OC43, 229E, NL-63, HUK1, adenovirus, RV, parainfluenza 1-3, human metapneumovirus and hBoV. Demographic, clinical and laboratory data were obtained from parents and from patient medical files. Main outcome measurements were age, breastfeeding history, family smoking habits, family history for asthma and atopy, blood eosinophil count, chest radiological findings, clinical severity score and number of days of hospitalisation. RESULTS: A virus was detected in 57.2% of the 182 infants. The most frequently detected viruses were RSV (41.2%), hBoV (12.2%) and RV (8.8%). Infants with dual infections (RSV and hBoV) had a higher clinical severity score and more days of hospitalisation than infants with RSV, RV and hBoV bronchiolitis (mean+/-SD: 4.7+2.4 vs 4.3+/-2.4 vs 3.0+/-2.0 vs 2.9+/-1.7, p<0.05; and 6.0+/-3.2 vs 5.3+/-2.4 vs 4.0+/-1.6 vs 3.9+/-1.1 days; p<0.05). Infants with RV infection had higher blood eosinophil counts than infants with bronchiolitis from RSV and hBoV (307+/-436 vs 138+/-168 vs 89+/-19 n/mm(3); p<0.05). CONCLUSIONS: Although the major pathogen responsible for bronchiolitis remains RSV, the infection can also be caused by RV and hBoV. Demographic characteristics and clinical severity of the disease may depend on the number of viruses or on the specific virus detected.

Immune complexed (IC) hepatitis C virus (HCV) in chronically and acutely HCV-infected patients.

In infected individuals, hepatitis C virus (HCV) exists in various forms of circulating particles which role in virus persistence and in HCV resistance to IFN therapy is still debated. Here, the proportion of HCV bound to immunoglobulin was determined in plasma of 107 chronically infected patients harbouring different HCV genotypes and, for comparison, of six patients with acute HCV infection. The results showed that, in spite of wide individual variability, chronically HCV-infected patients exhibited an extremely high proportion of immune complexed (IC) virus regardless of plasma HCV load and infecting genotype. Moreover, no significant association was found between baseline proportion of IC HCV and response to IFN treatment. Plasma samples collected within 2 weeks of treatment from 20 patients revealed a significant decline of mean IC HCV values relative to baseline that clearly paralleled the decay of total HCV load. In acutely infected patients, circulating HCV was not IC or IC at very low levels only in patients developing chronic HCV infection. Collectively, these findings strengthen the possibility that IC virus could play a critical role in the pathogenesis of HCV infection.

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.

Markers of human papillomavirus infection and their correlation with cervical dysplasia in human immunodeficiency virus-positive women.

Human papillomavirus (HPV) genotypes and HPV DNA load were analysed in cervical smears from 76 human immunodeficiency virus (HIV)-positive and 54 HIV-negative women. The prevalence of genotypes was similar for all women, with the exception of HPV62, which was over-represented in HIV-positive samples. HIV-positive women showed a higher prevalence of multiple genotypes that correlated neither with CD4(+) T-cell counts nor with cervical dysplasia. No significant differences were observed in terms of total or single-type HPV DNA load. The HPV DNA load in both HIV-positive and HIV-negative women was significantly higher in squamous intra-epithelial lesions than in negative Pap smears.

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).

Occult hepatitis C virus infection in type II mixed cryoglobulinaemia.

Mixed cryoglobulinaemia, when not secondary to other well-defined immunological disorders, is commonly associated with hepatitis C virus (HCV) infection. However, a minority of cases lack evidence of HCV infection and are, therefore, defined as 'true essential' mixed cryoglobulinaemias. We thoroughly investigated three such patients to determine the aetiology of this disorder. Antibodies to HCV (anti-HCV) and HCV RNA, detected by sensitive enzyme-linked immunosorbent and polymerase chain reaction assays in serum and in concentrated cryoglobulins, were repeatedly negative in the three patients. Despite the lack of evidence for HCV infection, two of them were still treated with interferon alpha-2a assuming unrecognized viral infection. Both patients demonstrated excellent clinical and laboratory responses, but cryoglobulinaemia relapsed after the withdrawal of therapy. At the time of relapse, HCV RNA genomic sequences were detected for the first time in the cryoprecipitates of both patients. In the third case, HCV RNA was demonstrated for the first time during a flare of cryoglobulinaemia coincident with varicella infection. In all three patients anti-HCV antibodies remained negative throughout follow-up. We conclude that some apparently 'essential' forms of mixed cryoglobulinaemia can be caused by occult HCV infection. Interferon therapy can be taken into consideration in such HCV-negative cases.

Impaired 2',3'-dideoxy-3'-thiacytidine accumulation in T-lymphoblastoid cells as a mechanism of acquired resistance independent of multidrug resistant protein 4 with a possible role for ATP-binding cassette C11.

Cellular factors may contribute to the decreased efficacy of chemotherapy in HIV infection. Indeed, prolonged treatment with nucleoside analogues, such as azidothymidine (AZT), 2',3'-deoxycytidine or 9-(2-phosphonylmethoxyethyl)adenine, induces cellular resistance. We have developed a human T lymphoblastoid cell line (CEM 3TC) that is selectively resistant to the antiproliferative effect of 2',3'-dideoxy-3'-thiacytidine (3TC) because the CEM 3TC cells were equally sensitive to AZT, as well as the antimitotic agent, vinblastine. The anti-retroviral activity of 3TC against HIV-1 was also severely impaired in the CEM 3TC cells. Despite similar deoxycytidine kinase activity and unchanged uptake of nucleosides such as AZT and 2'-deoxycytidine, CEM 3TC had profoundly impaired 3TC accumulation. Further studies indicated that CEM 3TC retained much less 3TC. However, despite a small overexpression of multidrug resistance protein (MRP) 4, additional studies with cells specifically engineered to overexpress MRP4 demonstrated there was no impact on either 3TC accumulation or efflux. Finally, an increased expression of the MRP5 homologue, ATP-binding cassette C11 (ABCC11) was observed in the CEM 3TC cells. We speculate that the decreased 3TC accumulation in the CEM 3TC might be due to the upregulation of ABCC11.

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.