Osamu Kobayashi

Clinical Role of Autoantibody against Bactericidal/Permeability-Increasing Protein in Chronic Airway Infection

Chronic airway infections often have persistent colonization of mucoid-derivative and/or biofilm-formed bacteria on the small airway surface. Such long-term colonization by bacteria sometimes induces harmful immune reactions in the host. Bactericidal/permeability-increasing protein (BPI) is one of the important agents in the phagocyte activity of neutrophils. An antineutrophil cytoplasmic autoantibody against BPI (BPI-ANCA) was recently detected. The clinical role of BPI-ANCA in 66 patients with chronic airway infections was investigated. Corresponding antigens in neutrophils against the antibody in their sera were observed by the indirect immunofluorescence method. After confiriming the antigen to be BPI, the presence of BPI-ANCA in their serum samples was determined by the enzyme-linked immunosorbent assay method. The titers were analyzed in relation to clinical symptoms, prognosis, and bacteriologic aspects, including in vitro examinations. Thirty-five of 66 samples (53%) were positive for cytoplasmic ANCA, and 48 cases (73%) were positive for serum BPI-ANCA. There were no positive cases among the sera samples of 7 healthy individuals. High titers of BPI-ANCA and a high frequency of BPI-positive indications were seen in cases with persistent colonization of gram-negative bacteria (P<0.05), and they also correlated with clinical symptoms and prognosis. In in vitro examinations, BPI-ANCA dose-dependently suppressed BPI that was induced by the interaction of neutrophils and gram-negative bacteria. BPI-ANCA is characteristically found in cronic infections, and it suppesses the BPI activity of neutrophils. An autoimmune manifestation such as this might increase the intractability of chronic airway infections.

JAID/JSC Guidelines for the Treatment of Respiratory Infectious Diseases: The Japanese Association for Infectious Diseases/Japanese Society of Chemotherapy - The JAID/JSC Guide to Clinical Management of Infectious Disease/Guideline-preparing Committee Respiratory Infectious Disease WG

a Center for Infectious Diseases, Nara Medical University, Nara, Japan b Shinrakuen Hospital, Niigata, Japan c Department of International Medicine, Division of Infectious Diseases, Faculty of Medicine, Saga University, Saga, Japan d Department of Infectious Diseases, Yamagata Prefectural Central Hospital, Yamagata, Japan e Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan f Department of Pediatrics, Kawasaki Medical School, Okayama, Japan g Department of Respiratory Medicine and Infectious Diseases, Oita University Faculty of Medicine, Oita, Japan h Sapporo Medical Academy, Hokkaido, Japan i Kyorin University, Tokyo, Japan j Department of Pediatrics, Asahikawa Kosei Hospital, Hokkaido, Japan k Division of Respiratory Medicine and Infection Control, Tohoku Pharmaceutical University Hospital, Miyagi, Japan l Department of Respiratory Medicine and Infectious Diseases, Niigata City General Hospital, Niigata, Japan m Infection Control and Prevention Center, Gunma University Hospital, Gunma, Japan n Department of Pathogen, Infection and Immunity, Nara Medical University, Nara, Japan o Department of Respiratory Medicine, National Hospital Organization Okinawa National Hospital, Okinawa, Japan p Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan q Kinki University Hospital, Faculty of Medicine, Osaka, Japan

Disease Characteristics and Treatment of 2009 H1N1 Influenza

In April 2009, novel H1N1 influenza was first detected in Mexico. This was a new influenza caused from a new type of virus that was originally referred to as “swine flu” because laboratory testing showed that many of the genes in this new virus were very similar to those in influenza viruses that normally occur in swine.