Repeatedly over the course of 3 years, the authors studied the state of cell-mediated immunity (CMI) by means of an antigen prepared from the serum of C3H/H2K strain inbred mice infected by the LDH virus in 74 patients with a malignant tumor in the area of the head or neck who were treated in the Otolaryngology Clinic of the 3rd Medical Faculty, Charles Universtiy, Prague. The immune response to the LDH virus was determined by the leukocyte adherence inhibition test (LAI test) and the evaluation was carried out by means of an index of positivity (IP). The aim of the Study was to: a. ascertain whether the mean index of positivity at a moment of capture exceeds 1.3 in patients with malignant tumors of the head and neck, which is the standard obtained by examination of healthy people (blood donors), and whether it exceeds that in patients with precancer of the area studied; b. ascertain whether values of the index of positivity mutually differ in malignancies of particular localizations; c. ascertain whether and how the index of positivity changes in time, i.e. whether or not it is an indicator of successfulness of the treatment; It has been determined that the IP values in patients with malignant tumors of the head and neck differ from those obtained by the exaination of healthy people and patients with precancers of the area studied. IP values of malignant tumors with particular localizations do not differ from one another significantly. It must be admitted that IP values change in the course of treatment, however, the changes are being affected by many circumstances and particular cases must be approached individually.

Keywords: LDH virus RNA, malignant tumors of the head and neck, marker of the disease