TRECS in age-related controls (white box: < 30 days, 6 months, 12 months, 18 months, 24 months and 36 months), patients (grey box) before thymectomy (prethymectomy) and patients after thymectomy (6 months, 12 months, 18 months, 24 months and 36 months post-thymectomy). Boxes are interquartile ranges, boxes lines are median values and external lines represent 5th and 95th percentiles. Significance was calculated using Student's t-test. P > 0·05 (not significant), *P < 0·05 and **P < 0·01. The higher discontinuous lines are statistical comparisons between prethymectomy and post-thymectomy patient samples and the lower discontinuous lines are statistical comparisons between < 30 days and the remaining control samples. Continuous lines are statistical comparisons between control groups and patient groups of the same age.