The Journal of Thoracic and Cardiovascular Surgery, Vol 106, 1065-1071, Copyright © 1993 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Immunoreactive thymosin alpha 1 in human thymus and thymoma
H Naruse, T Hashimoto, Y Yamakawa, M Iizuka, T Yamada and A Masaoka
Second Department of Surgery, Nagoya City University Medical School, Japan.
Thymosin alpha 1-like immunoreactivity was assessed in human thymus and
thymoma tissue extracts by means of a new radioimmunoassay that included an
anti-thymosin alpha 1 mouse monoclonal antibody. Thymosin alpha 1-like
immunoreactivity levels decreased with age in normal thymuses but not in
thymomas. The average thymosin alpha 1-like immunoreactivity level was 45.0
+/- 52.1 ng/mg protein in normal thymuses and 273.9 +/- 205.0 ng/mg protein
in thymomas. The average thymosin alpha 1-immunoreactivity level in
thymomas was higher than that in normal thymuses. Thymosin alpha 1-like
immunoreactivity levels in thymomas appeared to have no relationship to the
clinical stage of the thymoma or associated diseases. When viewed according
to histologic characteristics, the average thymosin alpha 1-like
immunoreactivity level in polygonal cell thymomas (382.5 +/- 192.6 ng/mg
protein) was significantly higher than that in the spindle cell thymoma
(101.8 +/- 81.2 ng/mg protein). When viewed according to the degree of
lymphocyte infiltration, thymomas could be classified according to four
grades: absent, scant, moderate, and predominant. In predominant or
moderate thymomas, the average thymosin alpha 1-like immunoreactivity level
was higher than that in scant or absent thymomas. Also, thymosin alpha 1-
like immunoreactivity levels in thymuses of patients with myasthenia gravis
were relatively higher than those in patients with normal thymuses.
