Authors: D. Nguyen, MJ. Dorsey, E. Perez, C. Duff, J Sleasman
Background: Patients with humoral immune deficiency receiving subcutaneous immunoglobulin (SCIG) are presumed to receive protective passive antibody against a variety of pathogens. The goal of this study is to determine if their steady state plasma titers to tetanus, varicella and Streptococcus pneumoniae are maintained in protective range while on SCIGÒ.
Methods: A cohort of 34 subjects [XLA/ARAG (n=4), HIGM pretransplant (n=2), SCID post BMT (n=1), CVID (n=12), SAD (n=14),THI (n=1)] who had been receiving SCIG in the form of VivaglobinÒ for at least 12 weeks were examined at 2 times points obtained 8 weeks apart. Plasma total IgG and specific IgG to varicella, tetanus and Streptococcus pneumoniae 10 to 14 serotypes were measured during steady state by standard methods.
Results: Mean IgG level at diagnosis was 386.2 mg/dL (33 – 877,±223.5). Mean IgG at steady state is 1103.3 mg/dL (490 – 1680, ± 237.8). Average VivaglobinÒ dose is 153.8 mg/kg/week (37.6 – 528.4, ±94.7). All subjects have protective tetanus and varicella titers with average tetanus titer of 2.7 IU/mL (0.6 – 6.9, ± 1.2) and varicella titers of 101.9 Eu/mL (41 – 315, ± 38.85). Eight out of 14 pneumococcal serotypes (or 57%) have average protective titer defined as greater than 1.3 mcg/mL. Pneumococcal serotype 14 has an average highest titer of 8.8 mcg/mL (0.1 – 112.1, ± 15.8) with over 96.9% of subjects having protective titers. Pneumococcal serotype 12F has the lowest titer of 0.4 mcg/mL (0.3 – 1.2, ± 0.3) and none of the studied subjects have protective titers to this serotype.
Conclusions: Subjects with primary immune deficiency who receive subcutaneous VivaglobinÒ and maintain average steady state IgG level above 1000 mg/dL have protective titers to tetanus, varicella and 8 out of 14 Streptococcus pneumoniae serotypes.