Serotype-specific immunoglobulin G (IgG) responses to the pneumococcal vaccine Pneumovax®23 were greater in patients with subnormal IgG1 than subnormal IgG3, according to data published in BMC Immunology.

Investigators compared the response to the Pneumovax®23 vaccine in 59 adults who demonstrated subnormal IgG subclass concentrations. These patients had normal total IgG, frequent/severe respiratory infection, and subnormal IgG1, IgG3, or IgG1 + IgG3 before and after vaccination.

The median days between pre- and post-testing for Pneumovax®23 testing was 33 (range 19 -158). The median post-vaccination summated concentration of serotype-specific IgG was higher in patients with subnormal IgG1 than subnormal IgG3, termed responders and non-responders. All non-responders with subnormal IgG1 + IgG3 demonstrated a 100% response to serotypes 8, 9, and 26; however, other non-responders did not. Lower responses to serotypes 1, 4, 12, 23, 26, and 51 were observed in responder participants with subnormal IgG3, while non-responders with subnormal IgG3 had higher responses to serotypes 1, 3, 8, 9, 12, 14, 19, 51, and 56.

Response rates deceased with age and aggregate responders were: subnormal IgG1, 54%; subnormal IgG3, 46%; and subnormal IgG1 + IgG3, 46%. Further analysis demonstrated that the prevalence of atopy was significantly lower in participants who were aggregate IgG responders compared with non-responders. Logistic regression on aggregate response found lower response with male sex (odds ratio, 0.09; 95% CI, 0.01-0.77) and atopy (odds ratio, 0.17; 95% CI, 0.03-0.83).

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The study excluded patients with subnormal IgG2 and lacked long-term follow-up of polyvalent pneumococcal polysaccharide vaccination with Pneumovax®23 (PPSV23) response stability, both of which were considered study limitations by investigators. Further, investigating the mechanisms by which variables like male sex, atopy, and autoimmunity influence vaccination responses was also beyond the scope of the present study.

According to the investigators, the IgG subclass responses to PPSV23 in adults with IgG subclass deficiency are “preferential and significantly associated with pre-vaccination IgG subclass immunophenotypes.”

Reference

Parker AR, Skold M, Harding S, Barton JC, Bertoli LF, Barton JC. Pneumococcal vaccination responses in adults with subnormal IgG subclass concentrations. BMC Immunol. 2019;20:29.

This article originally appeared on Infectious Disease Advisor