Establishment of ideal pneumococcal vaccine immunization program for high-risk patients

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K08817
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 54030:Infectious disease medicine-related
• Research Institution: Chiba University
• Principal Investigator: Naruhiko Ishiwada 千葉大学, 真菌医学研究センター, 教授 (30344980)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 肺炎球菌 / 13価肺炎球菌結合型ワクチン / 免疫原性 / ハイリスク / オプソニン活性 / メモリーB細胞

Outline of Final Research Achievements

We measured pneumococcal serotype-specific IgGs (Pn-IgGs) and opsonophagocytic activities (Pn-OPAs) against PCV13 serotypes in patients with hematological malignancies and solid tumors. Pn-IgGs were significantly elevated at 1 month post-vaccination against all six serotypes measured except serotype 3. Pn-OPAs and pneumococcal serotype-specific memory B cells against serotype 3were elevated after PCV13 vaccination. PCV13 is thus safe and immunogenic, including against serotype 3, in patients with hematological malignancies and solid tumors.
To evaluate the antibody response to PCV13 in patients with rheumatoid arthritis receiving Janus kinase inhibitors (JAKIs).Positive antibody response rates were comparable between the methotrexate (MTX) group and the JAKI group but lower in the MTX + JAKI group. Although JAKIs do not impair PCV13 immunogenicity in rheumatoid arthritis patients, the combination of MTX with JAKI can reduce the antibody response in this patient population.

Free Research Field

感染症学

Academic Significance and Societal Importance of the Research Achievements

本研究により肺炎球菌感染症の感染リスクの高い血液腫瘍疾患・骨髄移植患者および関節リウマチ患者に対する13価肺炎球菌結合型ワクチン（PCV13）接種の有効性（免疫原性）ならびに安全性について証明することができた。また、接種における具体的な留意点についても学術的に検証することができた。
本研究成果は、今後国内に導入される予定の新規肺炎球菌結合型ワクチン（PCV15、PCV20）のハイリスク者に対する接種スケジュールを検討する際の重要な基礎データとなり、ハイリスク患者の肺炎球菌感染症の積極的な予防に寄与することが期待される。その点からも本研究の社会的意義は高い。