Focusing on Good Responders to Pneumococcal Polysaccharide Vaccination in General Hospital Patients Suspected for Immunodeficiency. A Decision Tree Based on the 23-Valent Pneumococcal IgG Assay

• Published in: Frontiers in immunology Vol. 10; p. 2496
• Main Authors: Janssen, Lisanne M A, Heron, Michiel, Murk, Jean-Luc, Leenders, Alexander C A P, Rijkers, Ger T, de Vries, Esther
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 05.11.2019
• Subjects: humoral immunodeficiency; Immunology; pneumococcal polysaccharide response; pneumococcal vaccination response; polysaccharide response; primary immunodeficiency; serotype-specific assay; 23-valent IgG assay; pneumococcal vaccination response; polysaccharide response; primary immunodeficiency; serotype-specific assay; humoral immunodeficiency; VaccZyme; pneumococcal polysaccharide response
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2019.02496

Recently, the 23-valent IgG-assay was suggested as screening assay to identify responders to pneumococcal polysaccharide (PnPS)-vaccination with the serotype-specific assay as a second-line test. However, in a low pre-test probability general hospital setting predicting responders could be more valuable to reduce the number of samples needing serotyping. Serotype-specific PnPS antibody-assays were performed for suspected immunodeficiency in two Dutch general hospitals (Jeroen Bosch Hospital, 's-Hertogenbosch; Elisabeth Tweesteden Hospital, Tilburg). 23-Valent PnPS antibody-assays were subsequently performed in archived material. Data were analyzed using receiver operating characteristic curves (AUC) and agreement indices (ICC). Sera of 284 patients (348 samples) were included; 23-valent IgG-titres and the corresponding sum of PnPS-serotype specific antibodies showed moderate correlation (ICC = 0.63). In 232 conjugated-pneumococcal-vaccine-naïve patients (270 samples), a random 23-valent IgG-titer could discriminate between samples with and without ≥7/11, ≥7/13, or ≥6/9 pneumococcal serotypes when both cut-off values 0.35 and 1.0 μg/ml were used (AUC 0.86 and 0.92, respectively). All patients with a pre-immunization-titer ≥38.2 μg/ml and/or post-immunization-titer ≥96.1 μg/ml and none with a post-immunization-titer ≤38.5 μg/ml exhibited a good response to PnPS vaccination. Using these breakpoints as screening test to predict responders, only 24% of patients would require further serotyping, as opposed to 68% if breakpoints to predict responders would have been used. In a low pre-test probability setting, the 23-valent IgG-assay proved to be a reliable screening test for good responders in conjugated-pneumococcal-vaccine-naïve patients, reducing the overall number of patient samples needing further serotyping, thus reducing overall costs of pneumococcal vaccination response assessment.