Table 2.
Correlations between HI titres and immunoglobulin (Ig)G and IgM enzyme-linked immunosorbent assay (ELISA) levels, respectively. Anti-influenza levels before and after vaccination were measured against H1N1 and H3N2 in HC (healthy controls), rheumatoid arthritis (RA) patients treated with methotrexate (RA-MTX) or rituximab (RA-RTX) and correlated with HI titres
| IgG ELISA versus HI | H1N1 | H3N2 | |||
|---|---|---|---|---|---|
| T = 0 | T = 28 | T = 0 | T = 28 | ||
| HC | Spearman's r | 0·85 | 0·50 | 0·51 | 0·51 |
| P | <0·0001 | 0·0091 | 0·0076 | 0·0083 | |
| RA-MTX | Spearman's r | 0·69 | 0·82 | 0·68 | 0·66 |
| P | 0·0007 | <0·0001 | 0·0011 | 0·0017 | |
| RA-RTX | Spearman's r | 0·51 | 0·56 | 0·71 | 0·78 |
| P | 0·0129 | 0·005 | 0·0001 | <0·0001 | |
| IgM ELISA versus HI | H1N1 | H3N2 | |||
| T = 0 | T = 28 | T = 0 | T = 28 | ||
| HC | Spearman's r | 0·19 | 0·12 | 0·51 | 0·49 |
| P | n.s. | n.s. | 0·0081 | 0·0119 | |
| RA-MTX | Spearman's r | 0·71 | 0·5 | 0·32 | 0·32 |
| P | 0·0004 | 0·0236 | n.s. | n.s. | |
| RA-RTX | 0·6 | 0·54 | 0·51 | 0·62 | |
| P | 0·0025 | 0·0081 | 0·013 | 0·0018 |
n.s. = not significant.