THU0034 Salmonella typhi vi igg as a marker of immunosuppression in rheumatic disease
Authors: L. Williams, G. Candelas, C. Tange, J. Ochoa-Grullón, P. Macarrón, C. Morado, K.H. Llano, C. Martínez-Prada, A. Rodríguez de la Peña, B. Fernandez, J.-Á. Jover, S. Harding, S. Sanchez-Ramon, A. Parker
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Measurement of vaccine response may be used as a diagnostic tool to aid determination of antibody deficiency. The IgG response to pneumococcal polysaccharide vaccination (PPV) is currently used to assess T cell independent responses, however additional polysaccharide vaccines are under evaluation. In patients with rheumatic diseases (RD) treatment regimens can result in immunosuppression and subsequently secondary immune deficiency (SID). <h3>Objectives</h3> To measure the IgG response to Typhi Vi vaccination (TV) in RD patients presenting with antibody deficiency. To correlate immunosuppression with TV responses, as well as TV responses to clinical presentations, B cells and total IgG. Further, we interpret the responses in combination with the responses to PPV. <h3>Methods</h3> 35 RD patients were referred for immunological evaluation at Hospital Clínico San Carlos, Madrid, Spain. The responses to TV and PPV were measured using commercial human anti-<i>Salmonella</i> Typhi Vi IgG and pneumococcal capsular polysaccharide (PCP) IgG ELISAs kits. A TV responder was defined as achieving ≥32 IU/mL (lower limit of the normal range), a PCP IgG responder (&gt;50 mg/L), B cells were measured by flow cytometry (responder ≥6.6%) and total IgG by nephelometric assay (responder ≥600 mg/dL). For all measurements (+) indicates a responder and (-) indicates a non-responder. <h3>Results</h3> A greater percentage of TV- patients previously received non-biological treatment (79% vs 43%), specifically steroid treatments (68% vs 28%) and biological treatments (particularly CD20 and TNF alpha targets; 46% vs 14%). At presentation, TV non-responsiveness was associated with a higher frequency of upper respiratory tract infections (75% vs 57%), serious bacterial infections (21% vs 14%) and required slightly higher antibiotic usage (93% vs 71%). Stratification of the RD patients using the response the TV and PPV identified four groups of activity: TV+/PCP+, TV-/PCP+, TV+/PCP- and TV-/PCP-. In the presence of a normal response to PPV, the failure to respond to TV (TV-/PCP+) correlated with a higher frequency of previous non-biological treatment (84% vs 43%), biological treatment (47% vs 14%), steroids treatment (68% vs 29%) and were currently undergoing treatment (84% vs 29%, p=0.01) compared those who responded to TV (TV+/PCP+). At presentation TV-/PCP +patients had a greater incidence of upper respiratory tract infections (74% vs 57%), serious bacterial infections (16% vs 14%) and antibiotic usage (95% vs 71%). Non-responders to both vaccinations (TV-/PCP-) had a higher incidence of serious bacterial infections (25% vs 16%) and pneumonia (50% vs 32%) when compared to the TV+/PCP- group. When correlated with B cell number, 58% of B cells had a concentration of TV antibodies&lt;32 U/mL. <h3>Conclusions</h3> The response to TV correlated with underlying disease treatment and immunological presentation. Assessing the response to two polysaccharide vaccinations, TV and PPV, may provide a greater understanding of the T cell independent pathway and provide more clinical information for the clinician. <h3>Disclosure of Interest</h3> L. Williams Employee of: The Binding Site Group Ltd, G. Candelas: None declared, C. Tange Employee of: The Binding Site Group Ltd, J. Ochoa-Grullón: None declared, P. Macarrón: None declared, C. Morado: None declared, K. Llano: None declared, C. Martínez-Prada: None declared, A. Rodríguez de la Peña: None declared, B. Fernandez: None declared, J.-Á. Jover: None declared, S. Harding Employee of: The Binding Site Group Ltd, S. Sanchez-Ramon: None declared, A. Parker Employee of: The Binding Site Group Ltd