Immunology. In the article “Absence of tumor necrosis factor rescues RelA-deficient mice from embryonic lethality” by Takahiro S. Doi, Michael W. Marino, Toshitada Takahashi, Toshimichi Yoshida, Teruyo Sakakura, Lloyd J. Old, and Yuichi Obata, which appeared in number 6, March 16, 1999, of Proc. Natl. Acad. Sci. USA (96, 2994–2999), the following corrections should be noted:

In Table 1, page 2995, line 1 of the title, the second sentence, “Results of matings of TNF+/+ or TNF−/− mice with relA+/− mice,” should be removed.

In Table 2, page 2997, line 2, right column, the genotype of the male parent which currently reads “TNF+/−relA+/+” should read “TNF−/−relA+/−.”

In Table 2, page 2997, line 3, right-most column, the genotype of the offspring which currently reads “−+/−relA+/+” should read “TNF+/−relA+/+.”

In line 2 of Discussion, page 2997, the sentence that reads “TNF mediates this abnormality and the associated lethality, as viable RelA-deficient progeny without liver damage result from matings of TNF-deficient RelA-heterozygous mice with RelA-deficient mice” should read “TNF mediates this abnormality and the associated lethality, as viable RelA-deficient progeny without liver damage result from matings of TNF-deficient RelA-heterozygous mice.”