gms | German Medical Science

Introduction: Solid organ and hematopoietic stem cell transplant recipients are at great risk of influenza complications and yearly influenza vaccination is strongly recommended. Although seroresponse is frequently poor in these patients, clinical efficacy has been demonstrated in some studies. Thus, the role of cellular and humoral responses to influenza vaccine in transplant recipients needs to be better understood. We are conducting a prospective study to evaluate both humoral and T-cell responses to influenza vaccine. The results of humoral responses are presented in this abstract.

Methods: Kidney and lung transplant recipients received one dose of the inactivated influenza vaccine. Blood samples were taken immediately before and 45 days after vaccination. The hemagglutination inhibition assay (HIA) was used to evaluate seroresponse (a four-fold rise in HI antibody titers) and seroprotection (presence of HI titers ≥1:40) rates. The antigens used in the assay were provided by the CDC (Atlanta, GA, USA) and corresponded to the vaccine proposed to the Southern hemisphere in 2012 (A/California/7/2009 (H1N1)pdm09-like virus; A/Perth/16/2009 (H3N2)-like virus; B/Brisbane/60/2008-like virus).

Results: Thirty-eight kidney, 21 lung transplant recipients and 16 healthy controls were included. Geometric mean titers (GMT) of HI antibodies before and after vaccination are shown in the graphic (Figure 1 [Fig. 1]). A significant increase in GMT after vaccination was seen for H1 antigen in all groups (p=0.038), especially in lung recipients. GMT increase for antigens H3 and B did not reach statistical significance (p=0.09 and p=0.07, respectively).

No differences were seen among groups concerning to seroresponse and seroprotective Ab levels before and after vaccination, as shown in Table 1 [Tab. 1].

Conclusions: A significant rise in GMT after vaccination was seen for antigen H1. Considering any influenza antigen, an increase in seroprotection rates were seen in all groups, varying from 11.8% to 23.5% in control group; 20% to 35% in lung recipients and 13.1% to 28.9% in renal recipients.