Antibody response to pneumococcal vaccination as a function of preimmunization titer
Received 8 May 2008; received in revised form 11 September 2008; accepted 11 September 2008. published online 28 October 2008.
Background
The interpretation of an adequate response to the unconjugated 23-valent pneumococcal vaccine for serotypes having high preimmunization titers remains challenging.
Objectives
We sought to determine whether high preimmunization titers preclude a 4-fold or greater response to vaccination. Moreover, we sought to determine the effect of the following covariates on this response: absolute preimmunization titer value, age, sex, serum IgG level, and serum IgG subclasses.
Methods
We conducted a retrospective analysis of patients who were seen in our immune disorders clinic between 2001 and 2007 who had received the unconjugated 23-valent pneumococcal vaccine. Logistic regression was used to estimate the effect of different covariates, including preimmunization titer values, age, sex, IgG levels, and IgG subclass values, on the odds of a 4-fold or greater antibody response.
Results
Per serotype, 10% to 40% of subjects with a high preimmunization titer attained at least a 4-fold response to vaccination. However, the odds of a 4-fold or greater response were found to decrease as a function of the absolute preimmunization titer value with an absolute value for each serotype beyond which the odds ratio approached zero.
Conclusion
High pneumococcal preimmunization titers do not necessarily preclude a 4-fold or greater response to vaccination. However, there appear to be serotype-specific preimmunization titer values, ranging from 4.4 to 10.3 μg/mL, above which a 4-fold or greater response would not be expected. This response does not seem to be significantly affected by age, sex, IgG level, or IgG subclass value.
Reprint requests: Zuhair K. Ballas, MD, Division of Allergy-Immunology, Department of Internal Medicine, C42/E-13, GH, University of Iowa Hospitals and Clinics, 200 Hawkins Dr, Iowa City, IA 52242.
Dr Smith is supported by National Cancer Institute grant P30 CA086862-09. Dr Ballas is supported by VA Merit and National Institutes of Health grant AA014418-06.
Disclosure of potential conflict of interest: B. J. Smith has received research support from the National Institutes of Health. Z. K. Ballas has consulting arrangements with Novartis DSMB (National Institute of Allergy and Infectious Diseases) and has received research support from Talecris Biotherapeutics, VA Merit Review, and the National Institutes of Health. N. D. Hare has declared that he has no conflict of interest.
ABSTRACT