Immunity to pneumococcal antigens in kidney transplant recipients

In immunocompromized patients such as kidney transplant recipients, vaccination against Streptococcus pneumoniae is recommended by national guidelines. Streptococcus pneumoniae causes pneumonia and meningitis and is especially harmful after coinfection with influenza virus. The aim of this study was to define whether clinically stable kidney transplant recipients produce normal concentrations of antibodies after pneumococcal vaccination.

Forty-three consecutive patients were immunized with Pneumovax 23 and antibodies against 14 pneumococcal capsular polysaccharides (serotypes) were determined before and 4 weeks after vaccination. For the first time, a commercially available serotype-specific assay (Luminex technology) was used for antibody detection in transplant recipients.

After vaccination, patients displayed a significant increase (P<0.0001) in total antibody concentration against these 14 serotypes from a median of 12.1 mg/L (range: 2.6-124.0) before vaccination to 51.9 mg/L (4.0-160.7) 4 weeks after vaccination. In addition, they showed a significant increase (P<0.0001) in the number of serotypes recognized from a median of 9 (0-13) to 13 (3-14). Antibody responses after vaccination were only slightly lower than in a published cohort of vaccinated healthy controls (total antibody concentration: 61.5 mg/L [patients displayed 84% antibodies of healthy controls]; number of serotypes recognized: 14 (3-14), P=0.003 [Borgers et al., Clin Immunol 2010; 134: 198-205]). Spearman analysis indicated that the estimated glomerular filtration rate at the time of vaccination was significantly (P<0.05) correlated with the increase of antibody concentrations against several polysaccharides.

Kidney transplant recipients can produce almost normal concentrations of antibodies against pneumococcal polysaccharides, and better renal function may lead to higher levels of protection.