Differential immune response to influenza and pneumococcal vaccination in immunosuppressed patients after heart transplantation

Introduction. Patients after solid organ transplantation are at an increase d risk for microbial infections. Due to therapeutic immunosuppression, the response to active immunizations may be reduced. The serological efficacy o f pneumococcal and influenza vaccination was studied in heart transplant re cipients. Patients and Methods,;Sixteen patients over 1 year after heart transplantat ion and control patients were immunized with a 23-valent pneumococcal vacci ne and a triple-split influenza vaccine. Preand postvaccinal antibody titer s were serologically determined, including quantitation of specific antibod ies against nine pneumococcal serotypes. Results. Both vaccines were well tolerated without systemic reactions or in fectious complications. Median postvaccinal pneumococcal antibody titers in the transplant patients were comparable to controls (5513 U/ml, range: 694 -41007, vs. 5490 U/ml, range: 1088-38042; P=NS); vaccination was successful in 23/23 (100%) of controls and in 15/16 (94% plus 1 borderline positive c ase) of the transplant recipients. Specific antibody titers were similar fo r eight of nine serotypes; only the immune response against serotype 3 was reduced after transplantation. The efficacy of influenza vaccination was si gnificantly impaired in transplant patients against all three virus strains (62% vs. 97%, P<0.01/50% vs. 94%, P<0.001/37% vs. 80%, P<0.01), but 9/16 ( 56%) of patients still showed a sufficient immune response ttl two out of t hree virus strains. No clinical or demographic predictors of successful vac cination could be established. Conclusions. Pneumococcal vaccination under cyclosporine-based immunosuppre ssion after heart transplantation is safe and equally effective as in healt hy controls. In contrast, the immune response to influenza vaccination is s ignificantly reduced, although not completely abolished. This differential response might be accounted for by T cell-independent antibody production a gainst polysaccharide antigens contained in the pneumococcal vaccine.