Postvaccination antibody titers against seasonal and pandemic influenza antigens are lower in patients compared with controls. (A-D) Bar charts showing geometric mean antibody titers (GMT) against seasonal A/Brisbane/10/2007 (H3N2 SEA) antigen, panel A; B/Brisbane/60/2008 (B SEA) antigen, panel B; A/Brisbane/59/2007 (H1N1 SEA) antigen, panel C; and pandemic A/California/7/2009(H1N1)pdm09 (H1N1 PAN) antigen, panel D. Antibody titers in non-Hodgkin lymphoma (NHL) patients (N = 14 for each bar chart) and controls (N = 14 for each bar chart) were assessed before (T0) after 1 dose (T1) of Fluad (seasonal vaccine; panels A-C) and after 1 and 2 doses (T1 and T2, respectively) of Focetria (pandemic vaccine, panel D). Antibody titers were assessed by hemagglutinin inhibition assay. The obtained antibody titer was expressed as the reciprocal of the highest dilution of serum inhibiting hemagglutination. Tests were performed in duplicate. Baseline titers were similar between patients and controls. Postvaccination titers were lower in patients compared with controls. Error bars represent the upper 95% confidence intervals of the geometric means (truncated in the last histograms of the panels A and D; exact values: 399 and 534, respectively). P values are from 2-sided Mann-Whitney tests. (E-F) Single-subject dot charts showing antibody titers against A/California/7/2009(H1N)pdm09 strain at baseline and after 1 and 2 doses of Focetria in patients (N = 14) and controls (N = 14). Data are represented in Log₂ scale. In panel E T1 and T2 curves overlapped from patients no. 9 to patients no. 12. The 3 subjects who did not respond at all to the first administration (patients no. 4 and 12, panel E; and control no. 9, panel F) failed the second administration as well. (G) Seroconversion rate and seroprotection rate after seasonal (SEA) and pandemic vaccine in patients compared with controls (P values are from 2-sided Fisher exact test). Six patients (43%) had been diagnosed with aggressive NHL. Twelve patients (86%) received 1 line of chemotherapy and the same proportion had been treated with CHOP or CHOP-like regimens. Three patients (21%) received fludarabine containing regimens. SC indicates seroconversion; and SP, seroprotection.