Background. The immune responses to pneumococcal conjugate vaccine (PCV) are low in immunocompromised hosts. The effect of memory B cells on the immune response to PCV remains elusive. Methods. In this prospective study, 53 children who received 7-valent PCV were enrolled. Antipneumococcal immunoglobulin G (IgG) levels and opsonization index (OI) titers, along with lymphocyte subsets, were investigated in immunocompromised and immunocompetent hosts. Immunocompromised patients comprised 8 hematopoietic stem cell transplant recipients (group A) and 9 immunosuppressive therapy recipients (group B), and controls consisted of 14 children aged >1 year (group C) and 22 infants (group D). Results. Serotype-specific IgG concentrations and OIs in group A were lower than those in group C. These did not differ among groups B, C, and D. The rates of achieving immunity (defined as an IgG level of 1.0 μg/mL and an OI of 8) in group Awere also lower than in group C. Despite the sustained numbers of total T cells and B cells, CD27+ B-cell and CD4+ T-cell counts in group A were lower than those in group C. In group B, the immunoglobulin D-expressing CD27- B-cell count was only lower than that in group C. Conclusions. Circulating numbers of CD27+ B cells, rather than CD4+ T cells, may predict the effective PCV responses in immunocompromised children.
All Science Journal Classification (ASJC) codes
- Immunology and Allergy
- Infectious Diseases