Comparison of effector and memory response following 2009-2010 TIV. (a) Trivalent influenza vaccine (TIV) IgG antibody-secreting cells (ASC) at day five to day seven vs. frequency of IgG TIV-specific memory B cells and (b) change in hemagglutination inhibition (HAI) titer as measured at one month. Fold change in IgD-CD27++CD38++ plasmablasts at (c) day five to day seven vs. frequency of IgG TIV-specific memory B cells and (d) change in HAI titer as measured at one month. Each symbol represents an individual study subject. Healthy controls (HC; n = 9 to 11), rheumatoid arthritis (RA; n = 3 to 5), RA+methotrexate (MTX; n = 3 to 4), RA+aTNF (n = 3 to 6). Spearman one-tailed correlation co-efficient (r) and significance (P) is indicated.