• Newer understanding of the development of the immune system and novel methods to repair these defects promise cures for previously fatal diseases. The advances stem from the ability to define the developmental stages and describe the diseases at the gene level. Coordinate with this progress, recombinant DNA technology may soon permit the precise correction of the defect. For the moment, gene replacement is accomplished at the cellular level by bone marrow transplantation. Here too, rapid clinical advances now permit the use of nonsibling donors. The long-term results are equivalent to those obtained in the past when only HLA-matched siblings could donate. There is now a support group that is of inestimable value to the families of those who suffer from immunodeficiency. Thus, there has been both technological and social progress in the area of primary immunodeficiency. The future is clearly brighter each year.