[Structural and immunomorphological characteristics of the human fetal appendix]

Altogether 120 human 12-31 week-old embryonal appendices were examined by histological, histochemical and immunomorphological methods. It was demonstrated that the first lymphoid follicles in the appendix occur in a 17-week-old embryo. Beginning from this time mononuclear suspension can be isolated from the organ and T and B lymphocytes defined. The features of the intestinal mucosa areas where lymphocytes are reproduced, released into the intestinal lumen and eliminated from the organs via the vessels are described. In mononuclear suspension, T and B lymphocytes are demonstrated, first in equal amounts whereupon the percentage of B lymphocytes rises to 26%, while the T lymphocyte count remains within 18%. The authors do not regard the appendix as an analog of the Fabricius bursa but attribute it to the peripheral organs of the immunity system.