Sera from patients with undifferentiated nasopharyngeal carcinoma contain a factor which abrogates specific epstein‐barr virus antigen‐induced lymphocyte response

Abstract

A unique association of Epstein-Barr virus (EBV) with the undifferentiated nasopharyngeal carcinoma (NPC) is a well acknowledged phenomenon. We report here the detection of a factor present in the sera of NPC patients which inhibits the blastogenic response of lymphocytes from EBV seropositive individuals to EB virions or soluble antigens. This lymphocyte-stimulation inhibitor (LSI) was found to be associated with the IgA fraction of the serum immunoglobulins. No inhibitory activity was detected in the sera and their immunoglobulin fractions from healthy (both EBV-seropositive and seronegative) individuals and patients with other carcinomas of the head and neck region. Interestingly, the IgA-LSI was absent in the sera of NPC patients who were successfully treated and remained in remission, while it was readily detectable in the sera of NPC patients in relapse, LSI-positive IgA fractions did not inhibit mitogenic response of lymphocytes to phytohemagglutinin. Taken together, the data presented suggest that LSI is a specific inhibitor of the response of sensitized lymphocytes to EBV antigens and that it may indeed represent a marker of great clinical significance regarding undifferentiated nasopharyngeal carcinoma, particularly for its prognosis.

Selective homing of phenotypically lytic cells within nasopharyngeal carcinoma biopsies: Numerous CD8‐ and CD16‐positive cells in the tumor

“…Such suppressor factors have generally been identified as "blocking factor" (SBF) (Hellstrom and Hellstrom, 1974;Veltri et al, 1981). This factor has been also reported as an IgA-mediated Epstein-Barr (EBV)-specific lymphocyte stimulation inhibitor (LSI) in the sera of patients with EBV-associated nasopharyngeal carcinoma (NPC) (Sundar et al, 1982).…”

Klinik virusbedingter Tumoren

“…Dies laBt sich autoradiographisch mit dem Einbau von H 3 -Thymidin objektivieren [133]. Der LSI-Faktor hebt diese Reaktion vollig auf und wird nur bei Patienten mit floriden Nasenrachenkarzinomen gefunden, nicht jedoch bei NPC-Patienten, die sich in Remission befInden oder bei gesunden seropositiven Kontrollpersonen (diese Untersuchungwurde iibrigens mit Seren von 25 NPC-und 10 Kontrollpatienten der Kolner Klinik durchgefUhrt [396].…”