Cytological scoring for pancreatic specimens obtained by endoscopic ultrasound-guided fine needle aspiration.

OBJECTIVE: Cytological diagnosis of pancreatic specimens obtained by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is often challenging because of the small sample size or well-differentiated adenocarcinoma with weak cytological atypia. Therefore, the sensitivity and specificity of cytological diagnosis for pancreatic cancer should be improved. Hence, we aimed to clarify the utility of cytological scoring to distinguish malignant from benign lesions for cytological diagnosis of pancreatic EUS-FNA specimens. METHODS: Seven reviewers, including four cytotechnologists and three medical doctors, evaluated 20 morphological indices in pancreatic specimens obtained by EUS-FNA (malignant, n = 111; benign, n = 31). Statistical analyses were performed using Fisher's exact test, logistic regression analysis, the area under the receiver operating characteristic curve, and Youden index. RESULTS: Among the 20 indices, there was a high incidence rate (>40%) of the following 13 indices in malignant cases: irregular structure, hyperchromatic nucleus, irregular cell polarity, unclear cell boundaries, nuclear membrane thickening, anisonucleosis, overlapping, irregular nuclei, high nuclear-cytoplasmic ratio, binding decline, the simultaneous appearance of malignant and benign cells, enlarged nucleoli, and background necrosis. When we diagnosed pancreatic specimens using these 13 cytological indices, the cut-off value of 8/9 showed the highest Youden index (0.950) as well as high sensitivity and specificity in distinguishing malignant from benign specimens (98% and 97%, respectively). CONCLUSION: Thirteen cytological indices showed high sensitivity and specificity in differentiating malignant and benign lesions using pancreatic EUS-FNA samples. All 13 indices were important for diagnosing malignancy in the pancreatic cytology smear of EUS-FNA. Further validation studies are required.

Efficacy of recombinant measles virus expressing highly pathogenic avian influenza virus (HPAIV) antigen against HPAIV infection in monkeys.

Highly pathogenic avian influenza virus (HPAIV) is a serious threat not only to domestic fowls but also to humans. Vaccines inducing long-lasting immunity against HPAIV are required. In the present study, we generated recombinant measles virus (MV) expressing the hemagglutinin protein of HPAIV without the multibasic site necessary for its pathogenicity in chickens using the backbone of an MV vaccine strain (rMV-Ed-H5HA) or a wild-type MV-derived mutant (rMV-HL-Vko-H5HA). We examined protective efficacy of the candidate vaccines in the monkey infection model by the challenge with a HPAIV (H5N1). Cynomolgus monkeys inoculated with the candidate vaccines produced both anti-H5 HA and anti-MV antibodies. They recovered earlier from influenza symptoms than unvaccinated monkeys after the challenge with the HPAIV strain. Chest radiography and histopathological analyses confirmed less severe pneumonia in the vaccinated monkeys. Vaccination tended to suppress viral shedding and reduced the interleukin-6 levels in the lungs. Furthermore, the vaccination with rMV-Ed-H5HA of monkeys with pre-existing anti-MV immunity induced the production of anti-H5 HA antibodies. These results suggest that both candidate vaccines effectively reduce disease severity in naïve hosts, and that rMV-Ed-H5HA is a particularly good candidate vaccine against HPAIV infection.

Experimental infection of macaques with a wild water bird-derived highly pathogenic avian influenza virus (H5N1).

Highly pathogenic avian influenza virus (HPAIV) continues to threaten human health. Non-human primate infection models of human influenza are desired. To establish an animal infection model with more natural transmission and to determine the pathogenicity of HPAIV isolated from a wild water bird in primates, we administered a Japanese isolate of HPAIV (A/whooper swan/Hokkaido/1/2008, H5N1 clade 2.3.2.1) to rhesus and cynomolgus monkeys, in droplet form, via the intratracheal route. Infection of the lower and upper respiratory tracts and viral shedding were observed in both macaques. Inoculation of rhesus monkeys with higher doses of the isolate resulted in stronger clinical symptoms of influenza. Our results demonstrate that HPAIV isolated from a water bird in Japan is pathogenic in monkeys by experimental inoculation, and provide a new method for HPAIV infection of non-human primate hosts, a good animal model for investigation of HPAIV pathogenicity.