We have previously reported the presence of marked immune dysregulation with a dominant Th2 profile, in a population of Ethiopian immigrants (ETH) in Israel heavily infected with helminths. In order to characterize better this immune dysregulation we studied by flow cytometry the expression of several activation markers on peripheral T cell populations, and lymphocyte apoptosis, in blood samples obtained from 63 'new' ETH (recently arrived), 18 'old' ETH (> 5 years since immigration) and 34 non-Ethiopian Israelis. The main findings in the 'new' ETH group in comparison with the non-Ethiopian controls were: (i) decreased CD4 and increased CD8 lymphocyte counts; (ii) elevated levels of activated T cells (CD3, CD4 and CD8) expressing HLA-DR; (iii) decreased levels of 'naive' CD4+ cells (CD45RA+), with increased levels of 'memory' CD4+ cells (CD45RO+); (iv) decreased numbers of CD28+ CD8+ lymphocytes; (v) marked increase in lymphocyte apoptosis. These T cell alterations and activation profile remained unchanged in 10 'new' ETH in whom the helminth infections persisted for 6-11 months. In contrast, in 18 'old' ETH, without helminth infections, the T cell activation profile was within the normal range. These findings suggest that chronic helminth infections may have a profound effect on the immune system of the host that disappears after eradication of these infections and adjustment to the new environment. It should therefore be taken into consideration for every immunomodulation therapy and especially in vaccine design and trials, in regions endemic for helminth infections.

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Following an intensive health education programme, 8651 finger-prick blood samples, 4122 from a predominantly adult group attending a primary care clinic and 4529 from schoolchildren, were collected in Tamra, northern Israel. An enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG) was used to detect anti-Echinococcus granulosus antibodies, using both crude and purified antigens. The seroprevalence in the adult group was 0.48% (20/4122); optical density values were 0.1-0.14 in 10 subjects, 0.15-0.19 in 9, and > or = 0.2 in one; prevalences did not differ significantly between males and females or among age groups. Twenty-six of the schoolchildren (0.57%) were seropositive, 23 with optical densities of 0.1-0.14, one of 0.15-0.19, and 2 > or = 0.2. A high correlation was observed between ELISA positivity and both positivity in the arc 5 immunoelectrophoresis test and the presence of a high titre in the indirect immunofluorescence assay. Cross reactivity was observed with sera from schistosomiasis and ancylostomiasis patients, using both crude and purified echinococcal antigens. The results indicated that the IgG ELISA, using both crude and purified antigens, was very useful for seroepidemiological screening for echinococcosis, and that this condition is an emerging disease in northern Israel.

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