Studies of anti-lymphocyte antibody in patients with active SLE. II. Effect of anti-lymphocyte antibody on autoreactive cell clones

Subset specificity of antilymhocyte antibodies in systemic lupus erythematosus. II. Preferential reactivity with T4 + cells is associated with relative depletion of autologous T4 + cells

Using indirect immunofluorescence and flow cytometry, we determined the proportion and number of T3+, T4+, and T8+ cells in the peripheral blood of patients with systemic lupus erythematosus whose sera were positive for cold-reactive antilymphocyte antibodies versus values in patients whose sera were negative for these antibodies. There was a disproportionate reduction in T4+ peripheral lymphocytes when cold-reactive antilymphocyte antibodies preferentially cytotoxic for this subpopulation were present in autologous serum. The decrease in this subset was responsible for a reduction in the T4:T8 ratio; variation in the number and proportion of T8+ cells was insignificant. A similar, but autoantibody-independent, alteration in the T4+ subpopulation was found in patients who were receiving prednisone therapy. A relationship between T cell population abnormalities and systemic lupus erythematosus disease activity, per se, was not observed.

DNA-daunorubicin complexes specifically suppress in vitro spontaneous anti-DNA antibody production in lymphocytes of patients with systemic lupus erythematosus

Elevated production of anti-DNA antibody in patients with systemic lupus erythematosus (SLE) is a central problem in the pathogenesis of tissue injury. In the present study, we attempted to manipulate anti-DNA antibody production through the antigen-cytotoxic drug conjugates, DNA-daunorubicin complexes. The effect of DNA-daunorubicin complexes was determined by examining SLE lymphocytes for spontaneous in vitro production of anti-DNA antibody. These complexes, at 2 micrograms/ml, suppressed anti-DNA antibody production, but not total IgG production, which suggests that specific suppression of anti-DNA antibody production was achieved at this concentration. We believe that the DNA-daunorubicin complexes affected mainly B cells, since such suppression was obtained by treating B cells, as well as B plus T cells. Furthermore, the complexes had no effect on the proliferative responses of SLE T cells to DNA, phytohemagglutinin, or concanavalin A. These results indicate that DNA-daunorubicin complexes may have the potential for selectively suppressing anti-DNA antibody production in patients with SLE.

Changes in anti-lymphocyte and anti-Ia antibodies during pregnancy in systemic lupus erythematosus

Anti-lymphocyte antibodies reactive with monocyte-depleted lymphocytes, T cells, or B cells were studied in 43 nonpregnant and 23 pregnant systemic lupus erythematosus (SLE) patients. Anti-Ia specificity was assayed in an enzyme-linked immunosorbent assay system. No difference in mean lymphocytotoxicity was noted between pregnant and nonpregnant SLE patients; however, anti-Ia lymphocyte antibody associated with disease activity was lower (P less than 0.01) in pregnant than in nonpregnant SLE patients. Lymphocytotoxic or anti-Ia antibody activity did not reliably predict the outcome of individual pregnancies.

Immunoglobulin from systemic lupus erythematosus serum induces interferon release by normal mononuclear cells

Ig fractions from patients with systemic lupus erythematosus (SLE) were tested with cultured normal peripheral blood mononuclear cells for induction of interferon release. Lymphocyte eluates, euglobulins containing IgG and IgM, and IgG or IgM from DEAE or sucrose gradients all induced interferon production. Lymphocytotoxic antibody in SLE sera showed a high correlation with capacity of isolated Ig fractions to induce interferon. Most interferon produced was of the gamma type. Monoclonal SLE IgM antilymphocyte antibody induced interferon synthesis.

Cellular mechanism of DNA-specific antibody synthesis by lymphocytes from systemic lupus erythematosus patients

The cellular mechanism of anti-DNA antibody synthesis in patients with systemic lupus erythematosus (SLE) was studied by DNA-specific solid-phase radioimmunoassay. Anti-DNA antibody synthesis in response to DNA was T-dependent, and the experiments with reconstituted lymphocytes from identical twins discordant for SLE showed that B cells and T cells from SLE patients must cooperate to synthesize anti-DNA antibody. Anti-DNA antibody synthesis by lymphocytes from patients with inactive SLE was enhanced by T4 cells and suppressed by T8 cells in response to DNA. Although T4 cells from patients with active SLE could enhance anti-DNA antibody synthesis by autologous B cells, their T8 cells could not suppress anti-DNA antibody synthesis by autologous B cells. These results indicate that elevated anti-DNA antibody synthesis in response to DNA in patients with active SLE is due to abnormalities of both SLE B cells and SLE T cells. They further indicate that dysfunction of T8 cells from patients with active SLE may, in part, be responsible for deficient regulation of anti-DNA antibody synthesis.