Autoantibodies, autoimmunity and cancer (review)

There is a strong association between neoplasms and autoimmune diseases. Numerous autoimmune phenomena have been reported in malignancies and conversely: malignant tumors are diagnosed in increasing frequency in autoimmune conditions. We review the most common autoimmune diseases and autoantibodies found in malignancies, discuss the therapeutic role of these autoantibodies in cancer, and summarize the current knowledge on malignant transformation in autoimmunity.

Hyperimmunization of apo-E-deficient mice with homologous malondialdehyde low-density lipoprotein suppresses early atherogenesis

The role of the immune system in modulating atherosclerosis has recently been the subject of intensive research. Several previous authors have put forward a paradigm of the autoimmune process occurring in the vicinity of the plaque. Two recent studies have shown that immunization of rabbits with homologous modified low-density lipoprotein (LDL) led to suppression of atherosclerosis. In the current study we evaluated the effects of homologous malondialdehyde (MDA)-LDL immunizations on atherogenesis in apo-E-deficient mice. Two groups of female chow-diet-fed, apo-E-deficient mice (n = 10) were either immunized with homologous MDA-LDL or with phosphate buffer saline (PBS) at 2-week intervals. The mice were sacrificed 12 weeks following the primary immunization. The MDA-LDL-immunized mice were shown to develop high titers of anti-MDA-LDL antibodies. Atherosclerosis, determined by the lesion size at the aortic sinus, was significantly suppressed in the MDA-LDL-immunized mice as compared with their littermates immunized with PBS (mean area +/- S.D.; 74000 +/- 17300 microm2 versus 158000 +/- 12800 microm2; P < 0.01). No differences were found between the groups with respect to the cellular composition of the atherosclerotic plaques. The results of this study show that immunization with MDA-LDL has a protective effect in apo-E-deficient mice, and further suggests that this mouse model is suitable for studies of immunomodulation.

Aspirin for prevention of myocardial infarction. A double-edged sword

BACKGROUND

The use of low dose aspirin is associated with upper gastrointestinal bleeding, especially in the elderly. Anemia is one of the risk factors of acute myocardial infarction especially in patients with ischemic heart disease.

METHODS AND RESULTS

We present a series of fifteen patients treated with low dose aspirin for secondary prevention of ischemic heart disease who had upper GI bleeding and were admitted to our hospital because of unstable angina or myocardial infarction. Nine patients had acute myocardial infarction and six patients had unstable angina. The mean age of the patient was 72 +/- 9 years. Only two patients had a previous history of duodenal ulcer before their admission. The duration of aspirin therapy ranged from a few days to more than a year. Weakness, abdominal pain and melena were present in most of the patients between 2-7 days before the appearance of chest pain, and syncope was the chief complaint in 5 patients.

CONCLUSIONS

We conclude that aspirin which is given to patients in order to prevent myocardial infarction might cause myocardial infarction as a sequella of upper gastrointestinal bleeding. Lack of patient education was the primary cause of the delayed diagnosis of this complication. Instruction of patients treated by aspirin to seek medical advise because of symptoms of gastrointestinal bleeding could prevent acute myocardial infarction in patients treated by aspirin who have upper gastrointestinal bleeding.

Magnesium fortification of water. A possible step forward in preventive medicine?

Magnesium is an essential cation for more than 300 enzymes in our body. Among them, it is a cofactor for ATP metabolism. Diverse clinical manifestations have been reported in conjunction with Mg++ deficiencies, including sudden death, accelerated atherosclerosis, asthma, neurologic and even psychiatric clinical entities. Limited previous studies with Mg++ supplementation have shown to be of a large preventive advantages. We summarize the current literature concerning Mg++ supplementation and recommend to do so on national basis adding magnesium to the water supplies of large areas.

Target recognition of beta2-glycoprotein I (beta2GPI)-dependent anticardiolipin antibodies: evidence for involvement of the fourth domain of beta2GPI in antibody binding

Beta2-glycoprotein I (beta2GPI) is an absolute requirement for the binding of autoimmune anticardiolipin Abs (aCL) to cardiolipin (CL). We evaluated the target recognition of human beta2GPI by IgG derived from two patients with primary and two with secondary antiphospholipid syndrome. The total IgG serum fractions and beta2GPI affinity-purified IgGs were assessed by using various domain-deleted mutants (DM) of human beta2GPI (DMs: I-III, I-IV, II-V, III-V, IV-V, and V) and mouse mAbs against individual beta2GPI domains. The four IgGs bound slightly to CL in the absence of beta2GPI and showed increased binding in the beta2GPI presence. Following affinity purification of the IgGs on a beta2GPI column, reactivity toward CL was absent. DMs containing domain V inhibited the binding of biotinylated beta2GPI to CL. The addition to CL-coated plates of DM V, but not the other DMs, reduced the binding of all four IgGs. The anti-beta2GPI IgGs bound only to complete beta2GPI and DM I-IV coated on the plates. The binding to plate-adsorbed beta2GPI could be inhibited by complete beta2GPI and DM I-IV, the latter being a more efficient inhibitor. Further, the human anti-beta2GPI IgGs could compete with the binding to beta2GPI of Cof-21 mouse mAb (directed at domain IV), but not with the two other mouse mAbs. The results suggest that some "autoimmune:" beta2GPI-dependent anticardiolipin Abs recognize a beta2GPI target that is distinct from the CL-binding site in domain V. The target site for some antiphospholipid syndrome IgGs appear to reside in domain IV of beta2GPI.

Increased prevalence of autoantibodies in celiac disease

Several features suggest an immune mechanism operates in celiac disease. Information on the autoantibody repertoire in this condition is lacking. The purpose of the study was to investigate the reactivity of celiac patients sera to various autoantigens widely distributed in the human intestine. Seventy children, celiacs and controls, were evaluated for serum autoantibodies using ELISA and immunofluorescence. Celiac patients had increased prevalence of serum anti-single-stranded DNA (14%), anti-double-stranded DNA (23%), anti-cardiolipin (14%), and anti-endomysial autoantibodies (63%). The relevance of this finding on the extraintestinal manifestations of celiac disease or the coexistence of autoimmune conditions and celiac disease remains to be determined.

The pathogenic 16/6 idiotype in patients with silica associated systemic lupus erythematosus (SLE) and uranium miners with increased risk for development of SLE

OBJECTIVE

To investigate the prevalence of the 16/6 idiotype (16/6 Id), a major cross reactive idiotype of anti-DNA antibodies involved in the pathogenesis of experimental lupus, in subjects with an exogenous risk for the development of systemic lupus erythematosus (SLE).

METHODS

The titer of 16/6 Id was determined by ELISA in sera of uranium miners exposed to heavy quartz dust: 15 developed definite and 12 probable SLE, 34 had clinical symptoms, and 27 had only serological signs (medium to high titer anti-dsDNA antibodies) of possible connective tissue disease (CTD) development.

RESULTS

The prevalence of 16/6 Id was higher in all groups compared to healthy blood donors. It was 18.5% in miners with SLE (definite and probable) and 22.2-26.5% in miners with clinical and/or serological signs for developing CTD. All 16/6 Id positive miners were positive for anti-dsDNA antibodies and other autoantibodies associated with CTD. The prevalence of 16/6 Id in anti-dsDNA positive miners correlated slightly with CTD/SLE symptoms: 55.6% in patients with SLE, 47.4% in miners with possible CTD/SLE, and 22.2% in miners without CTD symptoms. Further, at short term followup, disease progressed in 2 miners of the 16/6 Id positive, but not in 16/6 Id negative miners.

CONCLUSION

The detection of 16/6 Id in miners exposed to quartz dust may indicate a higher risk for development of SLE, warranting further studies of the role of 16/6 Id in the development of SLE in a cohort with the same sex, ethnicity, geographic region, and occupation.

Differential effects of anti-beta2-glycoprotein I antibodies on endothelial cells and on the manifestations of experimental antiphospholipid syndrome

BACKGROUND

The antiphospholipid syndrome (APS) entails a prothrombotic state associated with the presence of anticardiolipin antibodies (aCL). aCL were shown to promote endothelial cell and platelet activation and to induce an APS-like syndrome in mice when administered intravenously. Recent data suggest that aCL target the plasma cofactor beta2-glycoprotein I (beta2GPI) rather than negatively charged phospholipids. However, it has not been determined whether different epitope-specific anti-beta2GPI antibodies obtained from one patient possess pathogenic properties.

METHODS AND RESULTS

Three beta2GPI-binding IgM monoclonal antibodies (mAbs) (ILA-1, ILA-3, and ILA-4) were cloned from a patient with APS. The three antibodies were shown to bind beta2GPI immobilized on irradiated plates, yet only ILA-1 bound beta2GPI coated onto nonirradiated plates. Furthermore, when using the anti-beta2GPI enzyme-linked immunosorbent assay, ILA-1 was the only mAb inhibited by fluid phase beta2GPI. ILA-1 and ILA-3, but not ILA-4, induced adherence of U937 cells to endothelial cells in vitro (reflecting activation of endothelial cells). mAbs ILA-1 and ILA-3 as opposed to ILA-4 induced significant expression of adhesion molecules when preincubated with human umbilical vein endothelial cells. Passive administration of ILA-1 and ILA-3 to pregnant BALB/c mice induced clinical findings consistent with APS (increased fetal resorptions, reduced platelet counts, and prolonged activated partial thromboplastin time), whereas both ILA-4 and the control human IgM did not produce similar effects.

CONCLUSIONS

The results of the study demonstrate the differential effects of various populations of anti-beta2GPI antibodies on endothelial cell activation and on experimental APS.

Ciprofloxacin immunomodulation of experimental antiphospholipid syndrome associated with elevation of interleukin-3 and granulocyte-macrophage colony-stimulating factor expression

OBJECTIVE

To evaluate the immunomodulatory potential of ciprofloxacin in mice with experimental antiphospholipid syndrome (APS).

METHODS

Ciprofloxacin or ceftazidime (control antibiotic) was given to mice with experimentally induced APS. The titers of autoantibodies, levels of cytokines, and number of cytokine-producing cells were determined by enzyme-linked immunosorbent assay. Myeloid progenitor cells were determined by granulocyte-macrophage colony-forming unit, and interleukin-3 (IL-3) messenger RNA (mRNA) was tested by Northern analysis.

RESULTS

A decrease in the incidence of pregnancy loss and an improvement in the clinical manifestations of APS were noted in the mice treated with ciprofloxacin, compared with the mice given ceftazidime. The effect of ciprofloxacin was found to be associated with increased serum levels of IL-3 and with increased IL-3 mRNA transcription in the splenocytes. Expression of granulocyte-macrophage colony-stimulating factor (GM-CSF) was documented by elevated titers in the sera and elevated numbers of colony-forming cells in the bone marrow.

CONCLUSION

Ciprofloxacin prevents the manifestations of experimental APS. This effect may be associated with increased IL-3 levels and GM-CSF expression.

Antiperinuclear factor--clinical, serological and genetic correlates in Israeli patients with rheumatoid arthritis

The possible association between the presence of antiperinuclear factor (APF) and clinical and genetic parameters was investigated in 54 Israeli patients with rheumatoid arthritis (RA). Rheumatoid factor (RF) was detected in the sera of 43 patients (80%) and APF was positive in 33 (61%). No significant statistical differences were found in the presence of HLA-DR4 and/or DR1 between APF-positive and -negative patients. Furthermore, neither the Ritchie articular index nor the patient's functional class correlated with the presence of APF. The results of our study suggested that although Israeli patients have a different genetic background, the presence and behaviour of APF is similar to that of other Caucasian populations.

Anti-DNA and antiphospholipid antibodies in IVIG preparations: in vivo study in naive mice

Intravenous immunoglobulins (IVIG) are therapeutic preparations of pooled normal polyspecific immunoglobulin G. We investigated the presence and the in vivo pathogenic potential of autoantibodies against phospholipids and DNA in several commercial IVIG preparations. The presence of autoantibodies and their antiidiotypic antibodies in the IVIG preparations was detected by ELISA. Naive mice were actively immunized with either IVIG preparations or pathogenic monoclonal antibodies (mAbs) against cardiolipin (CL) or DNA, in an attempt to induce autoimmune conditions. The mice were tested for the presence of mouse autoantibodies (auto-Abs) and for clinical parameters of autoimmune diseases. We found high levels of auto-Abs against a panel of phospholipids and DNA, as well as their antiidiotypic Abs, in all the IVIGs. Affinity studies pointed to a lower affinity of auto-Abs of IVIG origin to their respective antigens compared to pathogenic mAbs. Mice immunized with pathogenic anti-CL mAb had high levels of antiphospholipid auto-Abs, accompanied by thrombocytopenia, prolonged aPTT, and an increased fetal resorption rate. Mice immunized with pathogenic anti-DNA mAb had elevated anti-DNA and anti-CL auto-Abs, along with a high erythrocyte sedimentation rate, leukopenia, and significant proteinuria. Following immunization with IgGs from IVIG batches, mice developed high levels of auto-Abs against phospholipids and DNA, similar to mice immunized with pathogenic anti-DNA or anti-CL mAbs, but none of the mice expressed the clinical manifestations compatible with the presence of these autoantibodies. We conclude that commercial IVIG preparations contain high levels of antiphospholipid and anti-DNA auto-Abs, as well as their antiidiotypic Abs. Although these Abs induced the generation of mouse auto-Abs upon active immunization, following idiotypic manipulation they did not prove to be pathogenic in vivo.

The clinical significance of antityrosinase antibodies in melanoma and related hypopigmentary lesions

Antityrosinase antibody is a newly detected antibody in the sera of patients with melanoma or vitiligo. The serum level of the antibody is measured by enzyme-linked immunosorbent assay (ELISA). The autoantigen is tyrosinase itself, the enzyme that participates in pigment (melanin) formation by both melanocytes and melanoma cells Antityrosinase IgG antibodies were found to be present in high titers in sera of patients with vitiligo in comparison to patients with melanoma or healthy volunteers. The level of antityrosinase antibodies in patients with metastatic melanoma was significantly higher than the level in healthy subjects, but insignificantly higher than the level in patients with no evidence of disease. Patients with melanoma and MAH (melanoma-associated hypopigmentation; vitiligo-like) had the same level of antityrosinase antibodies as the controls or the patients with metastatic melanoma. This observation reflected the possible absorption of antityrosinase antibodies by melanoma antigens, and pointed to the participation of the antibodies in the destruction of normal melanocytes in patients with melanoma, as part of the immune reaction towards this disease. The most interesting observation was the high level of antityrosinase antibodies in patients with vitiligo in comparison with the low level in patients with melanoma, patients with MAH, and patients with NED. Although the cutaneous manifestations of vitiligo and MAH are similar and result from destruction of melanocytes by specific antibodies, the two situations are immunologically different. The serum level of free antityrosinase antibodies could not serve as marker for the state of the disease or disease progression or relapse, as no significant difference could be detected between the levels in patients without evidence of disease to those with metastatic melanoma; nor could the levels of antityrosinase antibodies differentiate between the different sites of the primary lesion. However, we have shown that antityrosinase antibodies could be used for monitoring the response to active specific immunotherapy by injection of anti-idiotypic antibodies mimicking the HMW-MAA. In the future, antityrosinase antibodies may be incorporated into immunotherapy for malignant melanoma.

Prevalence of hypophosphatemia in sepsis and infection: the role of cytokines

BACKGROUND

Sepsis occurs following the presence of bacteria in the circulation and is associated with fever, hyperthermia, and hypotension. Hypophosphatemia develops in the early stages of sepsis. High levels of inflammatory cytokines also characterize early sepsis.

AIM

The aim of the present study was to correlate hypophosphatemia with cytokines and cytokine receptor levels during early sepsis. We aimed to reestablish the results obtained from patients in an in vivo experimental model, in order to understand the mechanism of hypophosphatemia induction in early sepsis.

METHODS

Ninety-nine patients were enrolled in this study and their clinical condition was classified as the presence of infection, sepsis, and bacterial growth in blood cultures. Phosphate levels and cytokine levels were recorded. In order to determine whether hypophosphatemia is correlated to the increased inflammatory cytokines, we injected normal mice with recombinant cytokines and studied their effect on phosphate levels.

RESULTS

Our results revealed that 80% of the septic patients had hypophosphatemia associated with very high levels of tumor necrosis factor (TNF)alpha and interleukin (IL)-6 and of soluble IL receptor (sIL)-2R and IL-6R, especially in those patients with positive blood cultures. Injection of IL-6, TNFalpha and IL-1beta in mice markedly decreased the phosphate serum levels.

CONCLUSIONS

Significant associations were demonstrated between high levels of inflammatory cytokines and their receptors and between serum phosphate levels, especially in patients with positive blood culture. Our results point to a correlation between the high inflammatory cytokines levels and hypophosphatemia during early sepsis. Cytokine levels and hypophosphatemia may be included in sepsis evaluation and prognosis. Anticytokine strategies might, therefore, reverse hypophosphatemia and other parameters of sepsis.

Primary biliary cirrhosis. Is (and how much of) the pathology preventible?

Primary biliary cirrhosis (PBC) is a chronic, progressive cholestatic liver disease, which is invariably fatal. Circumstantial and indirect evidence suggests that autoimmune mechanisms have a role in the pathogenesis of PBC. Antimitochondrial antibodies (AMA) are highly sensitive and specific markers that can predict the development of the disease in a healthy individual. Long-term administration of ursodeoxycholic acid (UDCA), a naturally occurring bile acid, safely slows the progression of PBC, delays the need for liver transplantation, and postpones death. An effort should be made to identify the patients with PBC in the asymptomatic stage by the presence of AMA and to conduct a clinical trial in order to assess the benefit of long-term administration of UDCA on the prevention of the overt disease in these individuals.