Claudio Mele

Immunity to diphtheria in the 3–19 year age group in Italy

Diphtheria antibody level in serum samples obtained from 270 subjects aged 4-70 was measured by in vitro seroneutralization test on Vero cells. Of the studied population, 27.8% had an antibody titre below the protective level (< 0.01 IU/ml). The prevalence of susceptible subjects showed a significant age-related increase (p < 0.01), with the highest value (53.8%) in the 31-40 age group. Mean antibody titre was maximum in individuals aged 13-14, then decreased reaching the minimum level in the 41-50 age group. These data suggest that in individuals aged 30-50, diphtheria immunity is not satisfactory, both for prevalence of immune subjects and for antibody levels. Therefore, a revaccination of adults with reduced doses of diphtheria toxoid may be advisable.

Quantification of hepatitis C virus (HCV) RNA in a multicenter study: implications for management of HCV genotype 1-infected patients.

ABSTRACT Assessment of the viral load in hepatitis C virus (HCV) genotype 1-infected patients is critical before, during, and after antiviral therapy. In patients achieving a rapid virological response at week 4 of treatment, the viral load at the baseline is considered a predictive criterion of a sustained virological response 24 weeks after the discontinuation of treatment. A ≥2-log10 drop in the viral load at week 12 of treatment (early virological response) triggers the continuation of therapy. We organized a multicenter study (MS) for diagnostic laboratories involved in the quantification of HCV RNA. Commercial assays, including two based on real-time reverse transcription-PCR (TaqMan system), and in-house methods, were used by the 61 participants. The overall reproducibility of the commercial quantitative nucleic acid amplification techniques (qNAT) was acceptable. As the intermethod variability among commercial qNAT for HCV RNA was still present, the manufacturers of these test kits should join efforts to harmonize the means of quantification of HCV RNA. This study also shows that caution should be exercised when the baseline viral load is evaluated and when the 2-log10 reduction after 12 weeks of therapy is interpreted. Finally, this MS confirms the higher sensitivity of the commercial qNAT based on the TaqMan system, making them the elective assays for the monitoring of therapy.

External quality assessment for the detection of blood-borne viruses in plasma by nucleic acid amplification technology: the first human immunodeficiency virus and hepatitis B virus studies (HIV EQA/1 and HBV EQA/1) and the fifth hepatitis C virus study (HCV EQA/5)

Background and Objectives  This External Quality Assessment (EQA) study was aimed at assessing the proficiency of blood centres and blood product manufacturers in detecting, by nucleic acid amplification technology (NAT), the possible contamination of plasma with hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis B virus (HBV).

External quality assessment for the detection of HCV RNA, HIV RNA and HBV DNA in plasma by nucleic acid amplification technology : a novel approach

Background and Objectives  In this EQA study a novel approach was used to assess the performance of blood centres and blood product manufacturers in detecting the possible contamination of plasma with HCV, HIV and HBV by NAT.

Hepatitis C virus testing of plasma pools by nucleic acid amplification technology: external quality assessment

Since 1 July 1999, in accordance with European regulations, only batches of blood products obtained from plasma pools tested and found to be non‐reactive for hepatitis C virus (HCV) RNA are being released. As monitoring the performance of manufacturers involved in plasma pool testing is important to ensure reliable amplification techniques, the Istituto Superiore di Sanità, as the Italian regulatory authority, organized an external quality assessment study.

High proficiency in detecting the six major hepatitis C virus genotypes of laboratories involved in testing plasma by nucleic acid amplification technology

Summary Since the introduction of mandatory HCV RNA testing of plasma pools for fractionation by nucleic acid amplification technology, we have organised External Quality Assessment studies (EQAs) addressed to blood products manufacturers and blood centres. Here we report the results of a new EQA, the first one to include all six major HCV genotypes. The results, reported by laboratories worldwide, showed that genotypes 1, 2 and 3 were correctly identified in 100% of the tests, genotype 4 in 96·7% and genotypes 5 and 6 in 98·3% of the assays. As detection of all HCV genotypes is critical for laboratories involved in testing plasma for HCV, all six genotypes should continue to be included in the next EQA studies.

External quality assessment programmes for detection of HCV RNA, HIV RNA and HBV DNA in plasma: improved proficiency of the participants observed over a 2-year period

Background and Objectives  Two External Quality Assessment Programmes (EQAPs) were run in 2008 and 2009 to evaluate the proficiency of blood centres in detecting, by nucleic acid amplification techniques (NAT), the possible contamination of plasma with hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis B virus (HBV).

HBV DNA in plasma pools for fractionation

Chimerism after BMT has been documented by various genetic markers, RBC antigens, and, less frequently, by immunoglobulin allotypes. These markers are less sensitive than short tandem repeats (STRs), which provides a powerful tool for analysis of human polymorphisms. Application of STR analysis in patients undergoing allogeneic BMT has been used to detect mixed or complete chimerism, recurrent leukemia, and endogenous repopulation of marrow in early and late phases after transplant. It can detect minor populations of DNA in the period after transplant with adequate sensitivity, whereas traditional immunohematologic evaluation is limited because of the necessity of transfusing RBCs. 1

Detection of anti-HIV antibodies in immunoglobulin preparations: the significance of antibodies to the HIV-envelope

Four hundred and sixty-eight immunoglobulin preparations, produced between 1969 and 1989, were examined for anti-HIV antibodies by means of two competitive immunoenzymatic assays and the Western blot test. This study refers the results obtained by the three different methods. Such results show that the detection of anti-HIV antibodies in immunoglobulins may be performed on a routine basis using commercial kits intended for human sera. The meaning of the test and the role of antibodies against the HIV envelope proteins are emphasized.