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The rate of tissue kallikrein (EC 3.4.21.35) excretion into the urine has been examined with an active site-specific radioimmunoassay for kallikrein in renal transplant recipients, in post-uninephrectomy kidney donors, and in a normal control population. Normal individuals on uncontrolled diets excreted 96.88 +/- 7.00 (SEM) micrograms of active kallikrein/24 hr and 113.68 +/- 8.39 micrograms of total kallikrein/24 hr, as determined after trypsin treatment of urine samples. Uninephrectomized donors secreted significantly less (P less than 0.05) active (44.99 +/- 6.39 micrograms/24 hr) and total (73.59 +/- 11.95 micrograms/24 hr) kallikrein than either the entire normal population or an age-matched subpopulation. Recipients with good renal function who had received kidneys 2 to 13 years prior to kallikrein assay excreted less (P less than 0.05) active (13.21 +/- 2.50 micrograms/24 hr) and total (18.69 +/- 3.65 micrograms/24 hr) kallikrein than either normal or uninephrectomized populations. Similar values for active (11.05 +/- 1.56 micrograms/24 hr) and total (17.60 +/- 1.96 micrograms/24 hr) kallikrein were seen in patients who had received kidneys within 6 months of assay. Thus, kallikrein excretion in kidney recipients remains significantly lower than in uninephrectomized donors. As compared to normal individuals, the reduced kallikrein excretion in post-uninephrectomized kidney donors and in renal allograft recipients suggests that renal kallikrein excretion may reflect functional distal tubular mass.

Homologous guinea pig skin-sensitizing antibodies of the IgG1 class (as characterized by heat stability and persistence in skin for 7 days) were shown to persist systemically for 28–35 days. Persistence was shown by the anaphylaxis induced in guinea pigs following the intracardiac administration of the antibody and subsequent antigenic challenge by aerosol. Skin-sensitizing antibody of the IgE class, characterized by heat lability and persistence in skin for 14 days, still caused systemic anaphylaxis 42 days after the intracardiac administration of antibody. The IgG serum fraction from nonimmunized rabbits blocked systemic anaphylaxis in the guinea pig induced by aerosol following the passive transfer of heterologous (rabbit) and homologous IgG antibodies to ovalbumin, but not following the passive transfer of homologous IgE antibodies to ovalbumin.