Table 3.
Prevalence of autoantibody in the different quartiles of serum gammaglobulin concentration (g/dL)
| AAb | First quartile <1·5 N = 38 | Second quartile 1·5–1·9 N = 38 | Third quartile 2–2·6 N = 38 | Fourth quartile >2·6 N = 38 | Difference |
|---|---|---|---|---|---|
| RF | 6 (16) | 12 (32) | 13 (34) | 26 (68) | P < 0·0001 |
| ANA | 7 (18) | 5 (13) | 1 (3) | 1 (3) | P = 0·036 |
| SMA | 5 (13) | 3 (8) | 2 (5) | 4 (11) | n.s. |
| IF | 1 (3) | 3 (8) | 3 (8) | 4 (11) | n.s. |
AAb, autoantibodies; RF, rheumatoid factor; ANA, antinuclear antibody; SMA, smooth muscle antibody; IF, intrinsic factor; n.s., not significant.