Specific Polysaccharide Antibody Deficiency Clinical Trial
Official title:
The Polysaccharide Antibody Response Study: Typhim Vi Response and Allohemagglutinins Versus Pneumovax 23 Vaccine Response in the Diagnosis of Specific Polysaccharide Antibody Deficiency
Specific polysaccharide antibody deficiency (SPAD) is a primary immunodeficiency characterized by a deficient antibody production to capsular polysaccharides with normal total immunoglobulin levels. Patients suffer from recurrent ear-nose and throat infections and lung infections. SPAD can also occur as part of a primary immunodeficiency affecting other components of the immune system. Diagnosis of SPAD is hampered by difficulties with the interpretation of the Pneumovax 23 antibody response. The purpose of this study is to assess the diagnostic value of the Typhim Vi antibody response and allohemagglutinin titers as an alternative to the Pneumovax 23 response to detect polysaccharide specific antibody deficiency.
Healthy controls (n = 100) and patients with suspected SPAD (n = 100) will be immunized with
both Pneumovax 23 and Typhim Vi (age 18 months - 55 years). Analyses of anti-pneumococcal
polysaccharide antibodies and anti-Vi antibodies are performed before and 3-4 weeks after
vaccination. Also bloodgroup and anti-A/anti-B are assessed. Relevant clinical information
(ENT infections, lung infections, bronchiectasis, invasive infections) is obtained from the
patient file and history and is noted in a Case Report Form.
The diagnostic performance of Typhim Vi response and allohemagglutinins will be analyzed by
calculating sensitivity, specificity, predictive values, likelihood ratios and Receiver
Operating Characteristic curves for Typhim Vi and allohemagglutinins using pneumococcal
antibody response as the reference standard. The association between low Typhim Vi response
or low allohemagglutinins and clinical signs of polysaccharide antibody deficiency will be
studied by multiple logistic regression.
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Allocation: Non-Randomized, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Diagnostic