[Intradermal reaction to phytohaemagglutinin. Value in paediatrics (author's transl)].

The existence of a deficiency in cellular immunity is common in paediatrics, and hence the need for a simple and rapid test for its evaluation. We thus studied the intradermal reaction to phytohaemagglutinin (PHA) in 690 children and sought to establish a correlation with regard to age and stimulation in vitro (PHA lymphoblastic transformation test). Normally, the injection of 5 g of purified PHA is followed 24 hours later in the child aged over 1 month by an induration more than 8 mm in diameter and erythema larger than 10 mm. These diameters then increase regularly with age up to 15 years. It was possible to establish a correlation between the intradermal reaction and blastic stimulation in vitro in 80% of cases. The intradermal reaction to PHA was found to be decreased in numerous viral infections, foetal diseases, during prolonged corticosteroid therapy, and during chemotherapy, haematological disorders and congenital immune deficiencies affecting T function.