[Levels of humoral antibodies to Epstein-Barr virus in the population of Cuba]. / Urovni gumoral'nykh antitel k virusu Epshteina-Barr u naseleniia Kuby.

Indirect immunofluorescence was used to study the levels of humoral antibodies to capsid (VCA) and early (EA) antigens of Epstein-Barr virus (EBV) in sera of 322 normal subjects living in the province of Habana and varying in ages from several months to 93 years. The results suggest that the population of Cuba, like in other countries, is widely infected with EBV, although the pattern of spread of this infection has some specific features. In particular, the infection rate of the pediatric population (3--4 and 5--9 years) is moderately high, 73% and 65%, respectively, whereas in adult population it is rather low (62--86%) despite the tropical location of the country. In all the age groups examined, geometric mean titers (GMT) of antibody to VCA were also lower than in comparable groups of population from other countries. The observed high GMT of VCA antibody in persons over 55 years and a considerable increase in the number of positively reacting sera and sera with high antibody titers (greater than or equal to 1 : 160) agree with the data by other workers and appear to be due to reduced immunological defence of the cellular type in elderly people. Antibody to EBV EA were found in all the age groups examined, although in a small per cent. The subjects with high antibody titers to this antigen (greater than or equal to 1 : 40) were found more frequently in the two youngest age groups (0--2 and 3--4 years) which appears to be due to large amounts of virus usually occuring in the period of primary infection. The analysis of infectious mononucleosis incidence for 5 years (1972--1976) in various age groups of Habana province population indicates a general low level of incidence. Two small peaks in 3--4 and 15--19-year groups corresponded to increased GMT values of antibody to EBV EA in these particular age groups.

[IgG- and IgA-antibodies to the Epstein-Barr virus in the sera of patients with nasopharyngeal carcinoma in Cuba]. / IgG- i IgA-antitela k virusu Epshteina-Barr v syvorotkakh bol'nykh nazofaringeal'noi kartsinomoi na Kube.

Sera from 24 patients with nasopharyngeal carcinoma (NPC) and from 60 normal subjects were examined for the presence of IgG and IgA antibody to various antigens associated with Epstein-Barr virus (EBV). The results indicate that NPC in Cuba, like in other countries, was accompanied by high titers of EBV-specific IgG antibody the levels of which differed markedly from those in normal subjects. Serological activity of the patients differed depending on the stage of the illness and its duration. Geometric mean antibody titers to the capsid antigen (VCA), D and R components of early antigen (EA) of EBV complex were higher in patients with extensive tumour process (III--IV stages) and in patients with the duration of the disease since the onset less than 3 years. Sera of the most patients contained EBV-specific IgA antibody which were practically completely absent in sera of the control subjects. Alongside with characteristic manifestations of responsiveness to EBV observed by other workers, patients with NPC in Cuba had specific features: higher antibody titers to VCA than in Caucasian subjects in the countries where this disease occurred sporadically, like in Cuba; high levels of antibody to EA, frequently exceeding those in patients with NPC from endemic zones (for instance in Chinese patients); prevalence of EBV-specific antibody to the R component of EA complex.