Leucocyte migration-inhibition in systemic lupus erythematosus

PHA-induced cellular cytotoxicity. Inhibition by a nonimmunoglobulin factor present in sera from patients with active systemic lupus erythematosus

Phytohemagglutinin-induced cellular cytotoxicity by normal mononuclear cells (MNC) is inhibited by serum of patients with active untreated systemic lupus erythematosus (SLE) but not by that of patients with untreated inactive SLE or rheumatoid arthritis. Three-hour preincubation of normal MNC with SLE sera suffices to inhibit throughout the assay. Preincubation with phytohemagglutinin (PHA) before addition of sera does not prevent the inhibition. DEAE-cellulose chromatography, Sephadex G-200 fractionation and immunoelectrophoretic analysis have shown the nonimmunoglobulin nature of this factor. It is thermostable and not affected by deoxyribonuclease or ribonuclease treatment. The mitogen-induced cellular cytotoxicity-inhibiting factor seems to be independent of other serum factors capable of blocking PHA-induced blastogenic transformation.

Cell-mediated immunity in systemic lupus erythematosus

Cell-mediated immunity in systemic lupus erythematosus (SLE) was assessed by skin testing with six common antigens and by streptokinase-streptodornase (SK–SD) induced leucocyte migration inhibition in twenty-four SLE patients, who were age- and sex-matched with twenty-four healthy subjects or patients with diseases not known to be associated with immunological abnormalities. 25% of SLE patients were anergic, and the migration of their leucocytes was not inhibited in the presence of SK–SD. Depressed cell-mediated immune responses were significantly related to disease activity. Patients with inactive or mildly active SLE exhibited selective hyporeactivity to purified protein derivative (PPD), while those with moderately to severely active SLE had marked depression of cell-mediated immunity, as manifested by both skin testing with common antigens and leucocyte migration inhibition in response to stimulation by SK–SD. A significant positive correlation was found between absolute peripheral lymphocyte counts of the SLE patients and the number of their positive skin tests. Peripheral lymphocyte counts were significantly decreased in the anergic SLE patients and in those with moderate to severe disease activity. The correlation found between skin test reactivity and absolute lymphocyte count suggests lymphocytopenia as the mechanism of the immune suppression. On the other hand, lymphocytopenia alone cannot explain the depression of the leucocyte migration inhibition response to SK–SD observed in the SLE patients, because in this system a relatively constant number of lymphocytes is employed. In conclusion, the depression of cell-mediated immune responses in SLE is caused by both lymphocytopenia and lymphocyte hyporeactivity.

The modifying effect of autologous serum on leukocyte migration inhibition by liver antigens in systemic lupus erythematosus

The leukocyte migration test was used to examine patients with systemic lupus erythematosus (SLE) for evidence of cell-mediated immunity to human liver microsomes and mitochondria. Testing of both these antigens with leukocytes from patients was carried out simultaneously in culture medium enriched by either 20% fetal bovine serum (the standard test) or substituted 20% autologous serum. Normal controls showed little or no reactivity in the standard test whereas the SLE group revealed a high incidence of significant leukocyte migration inhibition to both antigens which, however, was considerably reduced by the substitution of autologous serum. The results suggest that the sera of patients with SLE contain factor(s) capable of blocking the in vitro expression of cell-mediated immunity to human tissue antigens. These factor(s), if active in vivo, might have a role in controlling some of the auto-immune manfestations of the disease.