Effect of enzyme treatment of Chrithidia luciliae on the reactivity of its kinetoplast with anti-DNA sera.

The reactions of sera from patients with connective tissue disease with Chrithidia lucillae kinetoplasts were examined with the indirect immunofluorescence technique on untreated smears and smears pretreated with DNAse, RNAse or trypsin. Of 28 completely examined reacting sera, 20 had their reactions inactivated by DNAse alone, two by DNAse and trypsin, and 6 by DNAse and RNAse. This suggests that although the Chrithidia test is probably at present the method of choice for the diagnostic demonstration of DNA antibodies, its results are not completely unambigous. The kinetoplast DNA is probably conjugated to a non-histone protein and antibodies to the conjugate may occur in some instances. In other instances, antibodies may be directed against DNA-RNA complexes. If the Chrithidia kinetoplasts contain a protein moiety, the latter is apparently not identical with the protein contained in the Chrithidian cell nuclei.