Concentrations of Pneumococcal IgA and IgM are compromised in some individuals with antibody deficiencies

Antibody responses after sequential vaccination with PCV13 and PPSV23 in kidney transplant recipients

PURPOSE

Vaccination against Streptococcus pneumoniae is recommended in transplant recipients to reduce the morbidity and mortality from invasive pneumococcal disease. Previous studies indicate that transplant recipients can produce specific antibodies after vaccination with the 13-valent pneumococcal conjugate vaccine Prevenar 13 (PCV13) or the pneumococcal polysaccharide vaccine Pneumovax 23 (PPSV23). National guidelines recommend sequential vaccination with PCV13 followed by PPSV23 in kidney transplant patients. However, there are currently no data on the serological response in kidney transplant recipients, who received a sequential vaccination with PCV13 and PPSV23.

METHODS

In the current study, we sequentially vaccinated 46 kidney transplant recipients with PCV13 and PPSV23 and determined global and serotype-specific anti-pneumococcal antibody responses in the year following vaccination.

RESULTS

Serotype-specific and global anti-pneumococcal antibody concentrations were significantly higher compared to baseline. We observed that serotype-specific antibody responses varied by serotype (between 2.2- and 2.9-fold increase after 12 months). The strongest responses after 12 months were detected against the serotypes 9N (2.9-fold increase) and 14 (2.8-fold increase). Global antibody responses also varied with respect to immunoglobulin class. IgG2 revealed the highest increase (2.7-fold), IgM the lowest (1.7-fold). Sequential vaccination with both vaccines achieved higher antibody levels in comparison with a historical cohort studied at our institute, that was vaccinated with PCV13 alone. During the 12-months follow-up period, none of the patients developed pneumococcal-associated pneumonia or vaccination-related allograft rejection.

CONCLUSION

In conclusion, we strongly recommend sequential vaccination over single immunization in kidney transplant recipients.

The clinical relevance of IgM and IgA anti-pneumococcal polysaccharide ELISA assays in patients with suspected antibody deficiency

Unlike immunoglobulin (Ig)G pneumococcal polysaccharide (PnPS)‐antibodies, PnPS IgA and IgM‐antibodies are not routinely determined for the assessment of immunocompetence. It is not yet known whether an isolated inability to mount a normal IgM or IgA‐PnPS response should be considered a relevant primary antibody deficiency (PAD). We studied the clinical relevance of anti‐PnPS IgM and IgA‐assays in patients with suspected primary immunodeficiency in a large teaching hospital in ’s‐Hertogenbosch, the Netherlands. Serotype‐specific‐PnPS IgG assays were performed; subsequently, 23‐valent‐PnPS IgG assays (anti‐PnPS IgG assays), and later anti‐PnPS IgA and IgM assays, were performed in archived material (240 patients; 304 samples). Eleven of 65 pre‐ and six of 10 post‐immunization samples from good responders to PnPS serotype‐specific IgG testing had decreased anti‐PnPS IgA and/or IgM titres. Of these, three pre‐ and no post‐immunization samples were from patients previously classified as ‘no PAD’. Determination of anti‐PnPS IgA and IgM in addition to anti‐PnPS IgG did not reduce the need for serotype‐specific PnPS IgG testing to assess immunocompetence [receiver operating characteristic (ROC) analysis of post‐immunization samples: anti‐PnPS IgA + IgG area under the curve (AUC) = 0.80, 95% confidence interval (CI) = 0.63–0.97; anti‐PnPS IgM + IgG AUC 0.80, 95% CI = 0.62–0.98; anti‐PnPS IgA + IgG + IgM AUC = 0.71, 95% CI = 0.51–0.91; anti‐PnPS IgG AUC = 0.93, 95% CI = 0.85–1.00]. Our data show that patients classified as having an intact antibody response based on measurement of serotype‐specific PnPS IgG can still display impaired anti‐PnPS IgM and IgA responses, and that the additional measurement of anti‐PnPS IgA and IgM could not reduce the need for serotype‐specific IgG testing. Future studies are needed to investigate the clinical relevance of potential ‘specific IgA or IgM antibody deficiency’ in patients with recurrent airway infections in whom no PAD could be diagnosed according to the current definitions.

Measurement and interpretation of Salmonella typhi Vi IgG antibodies for the assessment of adaptive immunity

Response to polysaccharide vaccination can be an invaluable tool for assessing functionality of the adaptive immune system. Measurement of antibodies raised in response to Pneumovax®23 is the current gold standard test, but there are significant challenges and constraints in both the measurement and interpretation of the response. An alternative polysaccharide vaccine approach (Salmonella typhi Vi capsule (ViCPS)) has been suggested. In the present article, we review current evidence for the measurement of ViCPS antibodies in the diagnosis of primary and secondary antibody deficiencies. In particular, we review emerging data suggesting their interpretation in combination with the response to Pneumovax®23 and comment upon the utility of these vaccines to assess humoral immune responses while receiving immunoglobulin replacement therapy (IGRT).