Katalin Lukacs

Circulating immune complexes and monocyte Fc function in autoimmune diseases.

The phagocytosis of separated and adherent monocytes of patients with systemic lupus erythematosus is subnormal as compared to controls on the basis of latex and yeast uptake. The monocytes from the same patients react with antibody-coated sheep red blood cells in a significantly higher degree than normal monocytes. There is a correlation between the percentage of reactive monocytes and the serum immune complex content. After brief treatment of patients with levamisole the phagocytic function of monocytes is restored and at the same time the circulating immune complex content is decreased.

Stimulating effect of tuftsin and its analogues on the defective monocyte chemotaxis in systemic lupus erythematosus

Monocytes and macrophages are engaged at various levels of cellular immune reactivity. In addition to their function in the defensive mechanism directed at infective agents, they also play a basic role in immune complex elimination and antigen handling. Previous experiments revealed that systemic lupus erythematosus (SLE), the main representative of the autoimmune diseases, is associated with impaired monocyte chemotaxis. The endogenous basic tetrapeptide tuftsin and 6 of its analogues were examined in vitro for their stimulating capacity on the chemotactic responsiveness of monocytes derived from patients with SLE. The monocyte migration assay was carried out by a modified Boyden technique and quantified by the leading front distance method and by counting the total distance covered by the monocyte locomotion. Tuftsin and 3 of its analogues significantly increased the defective chemotaxis in SLE. The tetrapeptides effective on chemotaxis also stimulated random migration and phagocytosis of the monocytes, albeit to a lesser extent. Structure-activity relationships, as well as the influence of the clinical stage of the disease were also examined. Experimental evidence leads to a favourable prediction for the immunotherapeutic value of these oligopeptides for the control of infections and the progression of the disease in patients with systemic lupus erythematosus.

Effects of immune complexes from SLE patients on human monocyte locomotion and Fc receptor function.

The effect of immune complexes (IC) isolated from systemic lupus erythematosus (SLE) sera with polyethylene glycol and gel filtration on the chemotaxis and Fc receptor function of healthy monocytes was examined. Even at a low protein concentration (1 microgram/ml = 1 mg/l) ICs inhibit monocyte chemotaxis. ICs from patients with SLE nephritis are more inhibitory than ICs from patients without renal disease. The inhibitory effects of ICs on monocyte chemotaxis and Fc receptor activity are similar, suggesting a relationship between the chemotactic and Fc receptor function of monocytes. Analysis of the ICs by enzyme-linked immunoassay showed no correlation between the quantity of IgG, C3, and anti-DNA in the IC samples and their effects on monocyte function.

Decrease in the carbamylcholine-induced chemotaxis of monocytes in myasthenia gravis

SummaryThe carbamylcholine-induced chemotaxis of monocytes was decreased in patients with myasthenia gravis, whereas no change was found in the C5a-induced locomotion of these cells compared with that of the normal controls. The decrease in the chemotaxis induced by carbamylcholine correlated with the severity of clinical symptoms. The beneficial effect of themectomy was also reflected in the improvement of chemotaxis. The method is simple, not expensive and could be used in the diagnosis of myasthenia gravis.