Nurse cells (NCs) are detected in lymph-epithelial organs. The aim was to test the hypothesis that NCs are among tonsil epithelium (group 1), vagina epithelium (2) and pleural fluid (3) and to define the diagnostic value of the palatine tonsil (PT) NCs in leukaemia. NCs were found in patients of group 1 in leukaemia, in group 2 – in dysplasia and cancer, in group 3 – in AIDS; NCs were not obtained from practically healthy patients (group 1- 3), in cancer (groups 1, 3) and different infections and inflammation diseases (group 1-3). Conclusions. NCs are abnormal cells. The PT NCs can be used for early diagnosis of leukaemia.