Development and Preliminary Evaluation of a Rapid Oligochromatographic Assay for Specific Detection of New Human Influenza A H1N1 Virus

A new oligochromatographic assay, Speed-Oligo Novel Influenza A H1N1, was designed and optimized for the specific detection of the 2009 influenza A H1N1 virus. The assay is based on a PCR method coupled to detection of PCR products by means of a dipstick device. The target sequence is a 103-bp fragment within the hemagglutinin gene. The analytical sensitivity of the new assay was measured with serial dilutions of a plasmid that contained the target sequence, and we determined that down to one copy per reaction of the plasmid was reliably detected. Diagnostic performance was assessed with 103 RNAs from suspected cases (40 positive and 63 negative results) previously analyzed with a reference real-time PCR technique. All positive cases were confirmed, and no false-positive results were detected with the new assay. No cross-reactions were observed when other viral strains or clinical samples with other respiratory viruses were tested. According to these results, this new assay has 100% sensitivity and specificity. The turnaround time for the whole procedure was 140 min. The assay may be especially useful for the specific detection of 2009 H1N1 virus in laboratories not equipped with real-time PCR instruments

Natalizumab-related anaphylactoid reactions in MS patients are associated with HLA class II alleles.

OBJECTIVES We aimed to investigate potential associations between human leukocyte antigen (HLA) class I and class II alleles and the development of anaphylactic/anaphylactoid reactions in patients with multiple sclerosis (MS) treated with natalizumab. METHODS HLA class I and II genotyping was performed in patients with MS who experienced anaphylactic/anaphylactoid reactions and in patients who did not develop infusion-related allergic reactions following natalizumab administration. RESULTS A total of 119 patients with MS from 3 different cohorts were included in the study: 54 with natalizumab-related anaphylactic/anaphylactoid reactions and 65 without allergic reactions. HLA-DRB1*13 and HLA-DRB1*14 alleles were significantly increased in patients who developed anaphylactic/anaphylactoid reactions (p M-H = 3 × 10(-7); odds ratio [OR]M-H = 8.96, 95% confidence interval [CI] = 3.40-23.64), with a positive predictive value (PPV) of 82%. In contrast, the HLA-DRB1*15 allele was significantly more represented in patients who did not develop anaphylactic/anaphylactoid reactions to natalizumab (p M-H = 6 × 10(-4); ORM-H = 0.2, 95% CI = 0.08-0.50), with a PPV of 81%. CONCLUSIONS HLA-DRB1 genotyping before natalizumab treatment may help neurologists to identify patients with MS at risk for developing serious systemic hypersensitivity reactions associated with natalizumab administration.