We describe a patient with leucocyte adhesion deficiency (LAD). Clinically, the patient had delayed umbilical cord detachment, omphalitis, impaired wound healing and persistent leucocytosis. The patient had the severe form of LAD, with a total absence of leucocyte cell adhesion molecules (LeuCAMs) and undetectable mRNA for the beta chain, the common subunit of the LeuCAMs. In vitro neutrophil chemotaxis, aggregation and oxygen consumption were severely impaired. In vitro incubation of neutrophils with recombinant human interferon-gamma (rIFN-gamma) showed an increase in oxygen consumption, but no effect on the expression of the LeuCAMs, or the beta chain mRNA. In vivo treatment with IFN-gamma was started. The Fc gamma RI receptor appeared on the neutrophils, the LeuCAMs remained undetectable, while the neutrophil functions remained disturbed. The patient died of surgical complications after 10 weeks of rIFN-gamma treatment. No new infections or side-effects due to rIFN-gamma were observed.