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Two schools in rural Tanzania were surveyed regarding the pupils' nutrition (weight and height), serum immunoglobulins (IgA, IgG, IgM, and IgE), autoantibodies, malaria antibodies, hepatitis B antigenemia, and fecal and urinary parasites. The survey attempted to quantify the relative importance of undernutrition and parasitic infestation in determining the serological abnormalities found. Of all the children surveyed 69% were undernourished (less than 80% of expected weight for age); 63% had fecal parasites and 38% had urinary schistosomiasis. Serum IgG and IgM concentrations were raised and the serum IgE concentration was strikingly raised (mean 4990IU/ml). Elevated serum IgE was associated with ascariasis. Autoantibodies were common but no autoimmune disease was detected. Notably there was a 35% prevalence of reticulin antibody. This reticulin antibody positivity correlated with increased malaria antibody concentrations. Reduced malaria antibody concentration was significantly associated with hepatitis B antigenemia. The study illustrates that parasites, notably malaria, are important determinants of the serum antibodies of children in the tropics and suggests that mild undernutrition has little effect.

It has been claimed that parasitic infestation suppresses the development of asthma. Eight Tanzanian schoolchildren in whom asthma was confirmed by the demonstration of exercise-induced bronchospasm were found in an ascaris-endemic area of rural Tanzania. Faecal parasites were found equally commonly in the children with asthma and the ninety-seven non-asthmatic controls. The prevalence of asthma (3.3%) in the school under study was comparable with that found in developed countries.

Microanalysis of subcellular organelle marker enzymes was applied to cryopreserved lymphocytes (obtained and processed in the field) from East African blacks with moderate to severe malnutrition and subject to locally endemic parasitic and infectious diseases. An initial study demonstrated that activities of these enzymes, with the partial exception of catalase, were stable to cryopreservation. Cryopreserved and thawed lymphocyte specimens (1 to 3 X 10(6) viable cells) from 26 Africans and 20 Caucasian controls were studied. There was a highly significant decrease in 5'nucleotidase activity in these African subjects. Activity of another plasma membrane enzyme, gamma-glutamyl transferase, and of marker enzymes for other intracellular organelles, was not significantly different between the two groups, indicating that the nucleotidase alteration is highly specific. 5'Nucleotidase activity in a group of 17 East African blacks of high socio-economic status lay between the values obtained in the other two groups and was not significantly different from either. Further studies on 5'nucleotidase showed no evidence that the enzyme is functionally different in Africans. The differences in activity of this enzyme in Africans may reflect the known immuno-suppressive effects of infectious disease and malnutrition or may have a genetic basis which may in turn be associated with the pathogenesis of secondary immunodeficiency.