Histiocytosis X. IV--Immunologic response assessed by lymphocyte transformation tests

Eight children with histiocytosis X were investigated with reference to immunologic reactivity in vitro (PHA, PWM, Con-A and MLC testing). No significant impairment of immune function was detected, but a subnormal (statistically insignificant) response in the MLC test may suggest some abnormality of the T lymphocytes reacting against allogeneic cells. In a patient who relapsed a marked, but insignificant, increase in lymphocyte reactivity in vitro was observed.