IgE antibody and resistance to infection. II. Effect of IgE suppression on the early and late skin reaction and resistance of rats to Schistosoma mansoni infection.

Most helminth parasites induce a strong IgE antibody and elevated eosinophil response in their mammalian hosts and a number of in vitro studies have suggested that IgE, possibly in association with eosinophils, may be an essential element of the host protective immunity against helminth infections. To assess the role of IgE in protective immunity, we examined the effect of suppressing the IgE antibody response on rat immunity to Schistosoma mansoni. Suppression was achieved in neonates by injections of rabbit anti-epsilon chain gamma-globulins, control rats received injections of unspecific gamma-globulins. IgE suppression caused a marked reduction of the inflammatory reaction that developed in the skin of immune rats at the site of a cercarial challenge: the early (30 to 60 min) wheal and flare reaction was abolished, and the late cutaneous reaction (6 to 18 h) associated with intense pruritus, edema and local eosinophilia was greatly reduced. This shows that IgE was critical to the recruitment of effector cells and molecules in the skin during the first 24 h following parasite invasion. Worms were recovered 18 to 30 days after a primary infection and 18 days after a challenge infection from IgE-suppressed and control rats. IgE-suppressed rats cured a first infection as rapidly as the control rats; however, they were two to three times less efficient than the controls at eliminating a second or a third challenge. These observations demonstrate that IgE antibodies are essential for the full development of rat acquired protective immunity against Schistosoma mansoni.

Frequency of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in Tanzanian males with typhoid fever.

The frequency of G-6-PD deficiency in the Dar es Salaam male population is given as 18.7%. In this preliminary study, is reported a frequency of 45% in males with typhoid fever--a figure more than twice the prevalence in the general Dar es Salaam male population. Possible reasons for positive correlation between the two disease states are described.

Correlation of glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and sickle cell trait (Hb-AS).

636 normal male blood donors were studied for haemoglobin genotype and G-6-PD deficiency. The results show that of 543 subjects with AA haemoglobin, 106 (19.5%) were G-6-PD deficient and of 93 individuals with AS haemoglobin 13 (14.0%). This difference is not significant.