Concentrations of pneumococcal polysaccharide antigen serotype-specific IgG antibodies and opsonisation indices in the RA treatment groups before and after 23-valent pneumococcal polysaccharide vaccination
| Serotype | MTX group (n=62) | TCZ+MTX group (n=54) | TCZ group (n=50) | RA control group (n=24) | p Values between treatment groups |
|---|---|---|---|---|---|
| IgG GMCs (μg/ml) | |||||
| 6B | |||||
| Before | 1.2 (1.0 to 1.5) | 1.1 (0.9 to 1.3) | 1.3 (1.0 to 1.7) | 1.1 (0.8 to 1.6) | NS |
| After | 2.2 (1.7 to 2.7)* | 1.7 (1.3 to 2.3)* | 6.1 (2.6 to 4.9)* | 2.5 (1.5 to 4.4)* | 0.004 (T/M vs T) |
| Fold increase | 1.5 (1.1 to 3.0) | 1.6 (1.2 to 1.9) | 2.8 (1.4 to 4.4) | 1.8 (1.3 to 3.7) | 0.036 (T/M vs T) |
| 23F | |||||
| Before | 1.0 (0.8 to 1.2) | 0.9 (0.7 to 1.2) | 1.3 (1.0 to 1.7) | 1.0 (0.6 to 1.5) | NS |
| After | 2.4 (1.8 to 3.3)* | 2.5 (1.8 to 3.5)* | 4.6 (3.4 to 6.4)* | 3.6 (1.8 to 5.7)* | 0.027 (M vs T) |
| Fold increase | 2.6 (1.4 to 4.1) | 2.9 (1.0 to 6.9) | 3.4 (1.5 to 6.8) | 3.5 (1.7 to 5.6) | NS |
| GM-OIs | |||||
| 6B | |||||
| Before | 18.8 (18.7 to 32.1) | 24.5 (14.7 to 42.1) | 43.8 (22.4 to 85.6) | 20.70 (7.0 to 61.0) | NS |
| After | 115.6 (64.1 to 206.4)* | 232.8 (124.0 to 437.0)* | 692.3 (265.1 to 1366)* | 262.4 (74.4 to 916.0)* | 0.001 (M vs T) |
| Fold increase | 4.5 (1 to 12.5) | 6.8 (1.7 to 35.5) | 12 (3.5 to 62.4) | 8.5 (2.2 to 52.0) | NS |
| 23F | |||||
| Before | 10.1 (6.6 to 15.3) | 15.5 (10.3 to 23.6) | 27.9 (15.2 to 51.4) | 17.6 (7.5 to 42.1) | 0.018 (M vs T) |
| After | 72.2 (39.3 to 133.0)* | 124.0 (62.2 to 244.7)* | 437.0 (221.4 to 862.6)* | 219.2 (82.3 to 578.2)* | 0.001 (M vs T) |
| 0.042 (M/T vs T) | |||||
| Fold increase | 7 .0 (2.7 to 15.8) | 5.0 (1 to 40) | 18.8 (2.7 to 75.1) | 11.0 (3.1 to 30.6) | NS |
IgG GMCs and GM-OIs are expressed as the mean (95% CI). Fold increases are expressed as the median (IQR). Differences between pre- and post-vaccination GMCs of serotype-specific IgG and those between pre- and post-vaccination GM-OIs were assessed using a paired-sample t test. The four treatment groups were compared using ANOVA (analysis of variance) with a Tukey's HSD (honestly significant difference) post hoc test or the Kruskal–Wallis test with a Scheffe post hoc test.
*p<0.0005 compared with pre-vaccination IgG GMCs or GM-OIs.
GMC, geometric mean concentration; GM-OI, geometric mean opsonisation index; M, MTX group; MTX, methotrexate; NS, not significant; RA, rheumatoid arthritis; T, TCZ group; T/M, TCZ+MTX group; TCZ, tocilizumab.