Lymphocytotoxins in vasculitis. Correlation with clinical manifestations and laboratory variables

Twenty-eight of 53 patients with various types of vasculitis were found to have cold reacting lymphocytotoxins (LCT). LCT were cytotoxic to both peripheral blood B and T cells as well as to OKT4 and OKT8 subpopulations. The interaction with the B cells was more pronounced than with the T cells as shown by reactivity with the former at higher serum dilutions than with the latter. Similar results were obtained with eluates from the unseparated lymphocytes and from B or from T cells. Partial purification of LCT demonstrated that they belong to the IgM class. LCT correlated with the level of circulating immune complexes as determined by the fluid phase C1q binding assay, but they did not correlate with the level of immunoglobulins, complement or antinuclear factors. The presence of LCT correlated significantly with the activity but not with the disease duration or the number of involved organs. Correlation of LCT with the activity of vasculitis implies that these cytotoxins may have a pathogenetic role and perhaps may serve as a marker for disease activity.