Table 1

Median values (and ranges) of IgG subclasses in sputum and serum from 44 patients with bronchiectasis

Nature of sputum
MucoidMucopurulentPurulent
IgG1
 Serum (g/l)6.77  (2.6–13.6)10.61  (4.4–13.4)7.17  (3.9–13.9)
 Sputum (g/l)0.10 (0.01–0.26)0.26 (0.1–0.37)0.40 (0.24–1.3)
 Sputum (% serum)1.47 (0.1–7.8)2.53 (0.9–7.5)5.99 (2.5–12.7)
 Ratio corrected for albumin1.42 (0.2–7.6)1.84 (0.1–15.3)3.20 (0.8–6.8)
IgG2
 Serum (g/l)4.33 (1.5–7.0)3.03 (1.5–6.9)4.07 (1.8–7.8)
 Sputum (g/l)0.06 (0.01–0.32)0.16 (0.06–0.49)0.23 (0.05–0.5)
 Sputum (% serum)1.73 (0.2–4.9)6.4 (1.3–27.6)5.74 (1.8–13.8)
 Ratio corrected for albumin1.38 (0.3–6.8)7.03 (0.4–26.7)2.13 (0.9–14.0)
IgG3
 Serum (g/l)0.66 (0.2–2.8)0.79 (0.4–1.5)1.15 (0.4–4.4)
 Sputum (g/l)0.03 (0.002–0.1)0.13 (0.06–0.22)0.22 (0.07–0.3)
 Sputum (% serum)4.17 (0.3–40.6)12.5 (5.9–45.7)16.92 (3.2–54.7)
 Ratio corrected for albumin3.65 (1.2–32.0)11.19 (1.9–69.1)8.33 (0.8–46.3)
IgG4
 Serum (g/l)0.29 (0.1–1.0)0.19 (0.1–3.4)0.20 (0.1–1.4)
 Sputum (g/l)0.04 (0–0.22)0.11 (0.03–0.3)0.21 (0–0.28)
 Sputum (% serum)6.44 (0.4–162.9)52.63 (2.9–175)32.18 (18.3–172)
 Ratio corrected for albumin5.90 (0.4–128.3)24.79 (0.7–193)12.12 (3.7–113)
  • Median values of sputum expressed as a percentage of serum are also shown together with this ratio corrected for the ratio of sputum to serum albumin. Values are divided into the three categories according to the usual nature of secretions produced by the patient when clinically stable.