A defect in chemotaxis of peripheral blood polymorphonuclear leukocytes (PMN's) was demonstrated in both parents and three of four children in a single family afflicted with varying degrees of respiratory allergy, unusual onset of severe eczema in the first month of life, and recurrent bacterial skin infections. Of great interest was the identification of HLA-B12 at the B locus in all affected members but not in the unaffected child. The two children known since infancy to be most severely affected with eczema and recurrent infections are HLA identical and homozygous for HLA-B12. The child without eczema and infections had an intermediate cellular chemotactic defect most apparent on kinetic studies.