New therapeutic avenues in autoimmunity.

During the last decade, much progress has been made in the understanding of processes that lead to autoimmunity. Cellular interactions mediated through cytokines and adhesion molecules were found to play a major role in the genesis of autoimmune conditions. During this period, we learned to recruit monoclonal antibodies to manipulate these delicate processes and to divert their outcome to a path we control better. Our comprehension of IVIG (intravenous immunoglobulin therapy) has broadened, and new indications for the implementation of this promising therapy have been pursued. In this review, we shed light on new therapeutic modalities that have been published since our previous report and discuss new data concerning the old modalities.

Levels of lupus autoantibodies in pregnant SLE patients: correlations with disease activity and pregnancy outcome.

OBJECTIVE: To follow the levels of lupus autoantibodies throughout pregnancy in a large cohort of pregnant SLE patients, and to examine whether they correlate with disease activity and pregnancy outcome. METHODS: 54 pregnancies in 46 SLE patients, and 70 control pregnant women were followed in the study. All patients were receiving steroid treatment. Titers of antibodies to ssDNA, dsDNA, histones, cardiolipin (CL) and phosphatidylserine (PS) were determined at the first, second, and third trimester and post-partum by ELISA. RESULTS: Overall the average levels of autoantibodies in all the patients were within the normal range, except for the average levels of anti-dsDNA antibodies which were elevated during the second trimester. Eight women (14.5%) had active disease during pregnancy, and there was a significant correlation between the levels of anti-dsDNA and the risk of disease activity (p = 0.0225). There were 7 fetal losses. There was a tendency for correlation between elevated anti-dsDNA levels, and anti-CL levels and the risk of fetal loss; however, this did not reach statistical significance (p = 0.0685, and 0.0881, respectively). There was a significant correlation between the levels of anti-dsDNA antibodies and the risk of preterm delivery (p = 0.0331). CONCLUSIONS: Pregnancy in SLE patients is associated with significant complications to both the mother and the fetus. Anti-dsDNA levels seem to correlate with the risk of disease exacerbation, and prematurity. Elevated levels of anti-dsDNA and anti-CL may suggest an increased risk of fetal loss.

The diverse pathogenic potential of anti-DNA antibodies from various sources to induce experimental systemic lupus erythematosus.

It has previously been shown that immunization with pathogenic anti-DNA idiotypes (Ids; e.g. 16/6 Id) leads to the induction of experimental system lupus erythematosus (SLF) in naive mice. The disease is characterized by serological (e.g. anti-double-strand DNA), clinical (elevation of erythrocyte sedimentation rate, leukopenia and proteinuria) and histological (immune complex deposition in kidneys) parameters. To determine whether the 16/6 Id carrying anti-DNA antibodies has unique pathogenic ability, in the current study we have employed diverse sources of anti-DNA antibodies to induce experimental SLE. An IgM anti-DNA antibody lacking the 16/6 Id was able to induce the production of the serological markers of experimental SLE, but not the clinico-histological findings. Furthermore, an IgA anti-DNA (16/6 Id derived from the serum of a patient with celiac disease was very effective in inducing the whole presentation of experimental SLE. Other anti-DNA antibodies failed to induce the autoimmune condition. Combined with our previous experience, the current study points to the diverse potential of various anti-DNA antibodies to induce SLE. The 16/6 Id is only one of a list of the potent pathogenic anti-DNA Ids. These facts may explain in part the diversity of clinical presentations of SLE, including asymptomatic subjects who carry high serum titers of anti-DNA antibodies.

Natural autoantibodies in sera of patients with Gaucher's disease.

Gaucher's disease (GD) is associated with hyperactivity of the immune system, which manifests by polyclonal hypergamma-globulinemia and an increased incidence of monoclonal gammopathies in GD patients. We analyzed sera of 43 patients with GD for the presence of autoantibodies against 14 autoantigens. The results demonstrated a significant increase in the incidence of all autoantibodies tested, ranging from 11% for anti-RNP, pyruvate dehydrogenase (PDH), and DNA antibodies to 57% for rheumatoid factor. The autoantibodies were of all three isotypes, namely, IgG, IgM, and IgA. There was no correlation between the levels of immunoglobulins in the serum and the titer of autoantibodies found. Immunization of naive mice with a pool of purified anti-DNA antibodies form GD patients did not result in induction of experimental systemic lupus erythematosus (SLE), suggesting that they may represent natural autoantibodies that are not pathogenic. In conclusion, we found high titers of natural, polyspecific, nonpathogenic autoantibodies in the sera of GD patients.

Autoantibodies in the sera of patients with lymphoma.

Sera of 84 patients with Hodgkin's disease (HD) and 55 patients with non-Hodgkin's lymphoma (NHL) were examined for the presence of autoantibodies to ssDNA, dsDNA, Poly (I), Poly (G), cardiolipin, histones, RNP. Sm, Ro (SS/A), La (SS/B) and the common anti-DNA idiotype (16/6) using an enzyme-linked immunosorbent assay (ELISA). Anti-ssDNA antibodies were detected in the sera of 20 patients with lymphoma (23.8%), more among those with NHL than HD (16 vs. 4 patients p < 0.01). Anti-RNP and anti-Sm antibodies were found in 16 (21.7%) and 14 lymphoma patients (20%) respectively, significantly more than in the controls (p < 0.05) in both antibodies). These findings remained valid following subgrouping of the patients into those with HD and NHL. With all the other autoantibodies examined no significant difference could be observed in the incidence between lymphoma patients and controls. These results differ from our previous survey carried out on sera of patients with solid tumors in whom no increased frequency of any of the autoantibodies could be determined. In view of the evidence suggesting an increased risk of lymphoma in a number of autoimmune diseases our results extend this relationship to an increased incidence of autoantibodies among patients with lymphoma.

Determination of autoantibodies in patients with familial Mediterranean fever and their first degree relatives.

Sera samples of 168 patients with familial Mediterranean fever (FMF) and their 184 first degree relatives were analyzed for the presence of autoantibodies to ssDNA, dsDNA, poly (I), poly (G), cardiolipin, histones, RNP and Ro(SSA), using an enzyme linked immunosorbent assay (ELISA). A similar analysis was employed on culture fluids of Epstein-Barr virus (EBV) transformed B lymphocytes derived from patients with FMF and healthy controls. No increased incidence of these antibodies was observed among patients with FMF and their relatives compared to healthy controls. It is possible that autoimmune features observed in FMF are the result of nonspecific changes occurring in inflammation and not due to autoimmune mechanisms.

Autoantibodies in neoplasia. An unresolved enigma.

One hundred sixty-four sera samples of patients with malignant diseases were analyzed for the presence of autoantibodies to ssDNA, dsDNA, poly(I), Poly(G), cardiolipin, histones, RNP, Sm, Ro(SSA), and La (SSB). No distinction could be made between these patients and a comparative group composed of age-adjusted healthy subjects when measuring antibody levels to these autoantigens by the ELISA technique. This finding remained valid after further subgrouping of the patients according to age, sex, and histologic origin of the tumor. The authors conclude that in contrast to the known clinical coexistence of neoplasia in autoimmune states, there is no increased incidence of antinuclear autoantibodies in malignant conditions.

Autoantibodies to histones and their subfractions in chronic liver diseases.

Sera of 78 patients with different chronic liver diseases were examined for the presence of anti-histone activity using an enzyme-linked immunosorbent assay. Eighteen patients had primary biliary cirrhosis (PBC), 20 had chronic active hepatitis, and 40 had cirrhosis. Anti-histone antibodies were detected in 34 patients (43.6%), distributed among all liver disease entities studied. When antibodies of specific isotypes (IgG, IgM, and IgA) were measured, even higher frequencies were noted--50% for IgG and 53.8% for IgA. Antibodies to histone subfractions H1, H2a, H2b, H3, and H4 were also observed in all liver disorders investigated (in 22-32% of patients)--H1 and H3 being the prominent fractions involved. Of the various disease entities examined PBC was the one disclosing the highest frequency of anti-histone antibodies.

Intermediatry steps in Acetobacter xylinum cellulose synthesis: studies with whole cells and cell-free preparations of the wild type and a celluloseless mutant.

Intermediatry steps in cellulose synthesis in Acetobacter xylinum were studied with resting cells and particulate-membranous preparations of the wild-type strain and of a celluloseless mutant. Exogenously supplied [1-14C]glucose was rapidly converted by resting cells of both types into glucose 6-phosphate, glucose 1-phosphate, and uridine glucose 5'-diphosphate (UDP)-glucose and incorporated into lipid-, water-, and alkali-soluble cellular fractions. The decrease in the level of labeled hexose-phosphates and UDP-glucose upon depletion of the exogenous substrate was accounted for by a continuous incorporation of [14C]glucose into cellulose in the wild type and into the above-mentioned cellular components in the mutant. [14C]glucose retained in the alkali- and water-soluble fractions of pulse-labeled wild-type cells was quantitatively chased into cellulose. Sonic extracts of both strains catalyzed the transfer of glucose from UDP-glucose into lipid-, water-, and alkali-soluble materials, as well as into an alkali-insoluble cellulosic beta-1,4-glucan. The results strongly support the sequence glucose leads to glucose 6-phosphate leads to glucose 1-phosphate leads to UDP-glucose leads to cellulose and indicate that lipid- and protein-linked cellodextrins may function as intermediates between UDP-glucose and cellulose in A. xylinum.

Factors affecting the activity of citrate synthase of Acetobacter xylinum and its possible regulatory role.

The citrate synthase activity of Acetobacter xylinum cells grown on glucose was the same as of cells grown on intermediates of the tricarboxylic acid cycle. The activity of citrate synthase in extracts is compatible with the overall rate of acetate oxidation in vivo. The enzyme was purified 47-fold from sonic extracts and its molecular weight was determined to be 280000 by gel filtration. It has an optimum activity at pH 8.4. Reaction rates with the purified enzyme were hyperbolic functions of both acetyl-CoA and oxaloacetate. The Km for acetyl-CoA is 18 mum and that for oxaloacetate 8.7 mum. The enzyme is inhibited by ATP according to classical kinetic patterns. This inhibition is competitive with respect to acetyl-CoA (Ki = 0.9 mM) and non-competitive with respect to oxaloacetate. It is not affected by changes in pH and ionic strength and is not relieved by an excess of Mg2+ ions. Unlike other Gram-negative bacteria, the A. xylinum enzyme is not inhibited by NADH, but is inhibited by high concentrations of NADPH. The activity of the enzyme varies with energy charge in a manner consistent with its role in energy metabolism. It is suggested that the flux through the tricarboxylic acid cycle in A. xylinum is regulated by modulation of citrate synthase activity in response to the energy state of the cells.

Activities of citrate synthase and other enzymes of Acetobacter xylinum in situ and in vitro.

The activities of a number of enzymes, extracted from Acetobacter xylinum, that are involved in carbohydrate metabolism may be accounted for in situ in permeabilized cells. The kinetic properties of citrate synthase and glycerokinase observed in vitro are also retained in situ. So is the regulatory sensitivity of these enzymes. Both in vitro and in situ, (a) citrate synthase, in contrast with the enzyme for other Gram-negative bacteria, is inhibited by ATP and is insensitive to NADH, and (b) glycerokinase is inhibited by fructose diphosphate and the ratio of its activities towards glycerol and dihydroxyacetone is the same.