Measurement of Typhim Vi® IgG antibodies in healthy donors as a tool for the diagnostic of patients with antibody deficiencies

Salmonella Typhi Vaccination Response as a Tool for the Stratification of Risk in Patients with Predominantly Antibody Deficiencies

“…Besides its role in diagnosis, the same study reported that vaccination with S. Typhi could be useful in monitoring IgG therapy (IgGpv), because commercial IgG preparations did not contain measurable anti ViCPS antibodies due to a lack of immunization in our environment [ 16 ]. Our group published a study of vaccination in healthy individuals where similar results were obtained [ 11 ]. IgG therapy is expensive, a limited resource, and a long-term necessity for PID patients, which has to be used efficiently.…”

“…Polysaccharide Salmonella Typhi Vi-based vaccination appears as a suitable alternative candidate vaccine to assess the immune response of patients with suspected PIDs [ 9 , 10 ]. Our group has already demonstrated that a sufficient response in fold increases can be achieved in healthy individuals, and preliminarily in PID patients, as well as other groups [ 9 , 10 , 11 ]. As typhoid fever is not endemic in our environment and vaccine recommendations are only for travelers to countries with a high risk of infection at destination, only very isolated cases present basal antibody levels against S. Typhi [ 11 ].…”

“…Intervals were chosen after previously published studies [ 9 ] and our own research of immune response to S. Typhi vaccination in healthy individuals [ 11 ].…”

“…The use of vaccination with pneumococcal conjugate vaccines (PCV) as a routine clinical practice has worked in detriment of the diagnosis of immunodeficiency, due to shared pneumococcal serotypes contained in both vaccines. This has led to increased basal levels of anti-pneumococcal antibodies in individuals where an increase of the immune response after a second exposure may be difficult to interpret [ 10 , 11 ]. Thus, clinicians find themselves in a situation where few tools are available to diagnose antibody deficiencies [ 12 ].…”

“…As with PPSV vaccines, diagnosis requires measuring antibody production before vaccination and four weeks after, and calculating the difference between the measured titers expressed as fold increases (FI). Recent studies have shown that response against S. Typhi ViCPS vaccine performed better than the global (non-specific type) responses of 11 pneumococcal antibodies for the discrimination of patients with common variable immunodeficiency (CVID) and hypogammaglobulinemia of healthy control subjects [ 11 , 15 ]. The EMPATHY study established a cut-off value of 3 FI and IgG of 32 U/mL in post-vaccination samples [ 15 ].…”