Gender Bias in Human Systemic Lupus Erythematosus: A Problem of Steroid Receptor Action?

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease resulting from abnormal interactions between T and B cells. The acquisition of SLE is linked to genetic susceptibility, and diverse environmental agents can trigger disease onset in genetically susceptible individuals. However, the strongest risk factor for developing SLE is being female (9:1 female to male ratio). The female sex steroid, estradiol, working through its receptors, contributes to the gender bias in SLE although the mechanisms remain enigmatic. In a small clinical trial, monthly administration of the estrogen receptor (ERα) antagonist, ICI182,780 (fulvestrant), significantly reduced disease indicators in SLE patients. In order to identify changes that could account for improved disease status, the present study utilized fulvestrant (Faslodex) to block ERα action in cultured SLE T cells that were purified from blood samples collected from SLE patients (n = 18, median age 42 years) and healthy control females (n = 25, median age 46 years). The effects of ERα antagonism on estradiol-dependent gene expression and canonical signaling pathways were analyzed. Pathways that were significantly altered by addition of Faslodex included T helper (Th) cell differentiation, steroid receptor signaling [glucocorticoid receptor (GR), ESR1 (ERα)], ubiquitination, and sumoylation pathways. ERα protein expression was significantly lower (p < 0.018) in freshly isolated, resting SLE T cells suggesting ERα turnover is inherently faster in SLE T cells. In contrast, ERα/ERβ mRNA and ERβ protein levels were not significantly different between SLE and normal control T cell samples. Plasma estradiol levels did not differ (p > 0.05) between SLE patients and controls. A previously undetected interaction between GR and ERα signaling pathways suggests posttranslational modification of steroid receptors in SLE T cells may alter ERα/GR actions and contribute to the strong gender bias of this autoimmune disorder.

Estradiol differentially regulates calreticulin: a potential link with abnormal T cell function in systemic lupus erythematosus?

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disease that affects women nine times more often than men. The present study investigates estradiol-dependent control of the calcium-buffering protein, calreticulin, to gain further insight into the molecular basis of abnormal T cell signaling in SLE T cells.

METHODS

T cells were purified from blood samples obtained from healthy females and SLE patients. Calreticulin expression was quantified by real-time polymerase chain amplification. Calreticulin and estrogen receptor-α were co-precipitated and analyzed by Western blotting to determine if the proteins associate in T cells.

RESULTS

Calreticulin expression increased (p = 0.034) in activated control T cells, while estradiol decreased (p = 0.044) calreticulin in resting T cells. Calreticulin expression decreased in activated SLE T cell samples and increased in approximately 50% of resting T cell samples. Plasma estradiol was similar (p > 0.05) among SLE patients and control volunteers. Estrogen receptor-α and calreticulin co-precipitated from nuclear and cytoplasmic T cell compartments.

CONCLUSIONS

The results indicate that estradiol tightly regulates calreticulin expression in normal human T cells, and the dynamics are different between activated and resting T cells. The absence of this tight regulation in SLE T cells could contribute to abnormal T cell function.

Estradiol targets T cell signaling pathways in human systemic lupus

The major risk factor for developing systemic lupus erythematosus (SLE) is being female. The present study utilized gene profiles of activated T cells from females with SLE and healthy controls to identify signaling pathways uniquely regulated by estradiol that could contribute to SLE pathogenesis. Selected downstream pathway genes (+/- estradiol) were measured by real time polymerase chain amplification. Estradiol uniquely upregulated six pathways in SLE T cells that control T cell function including interferon-alpha signaling. Measurement of interferon-alpha pathway target gene expression revealed significant differences (p= 0.043) in DRIP150 (+/- estradiol) in SLE T cell samples while IFIT1 expression was bimodal and correlated moderately (r= 0.55) with disease activity. The results indicate that estradiol alters signaling pathways in activated SLE T cells that control T cell function. Differential expression of transcriptional coactivators could influence estrogen-dependent gene regulation in T cell signaling and contribute to SLE onset and disease pathogenesis.

Efficacy of intravenous gammaglobulin for immunoglobulin G subclass and/or antibody deficiency in adults

BACKGROUND

The clinical significance and efficacy of treating patients who have immunoglobulin (Ig) G subclass deficiency and/or antibody deficiency with Ig-replacement therapy has been debated. There are no clear guidelines to recommend intravenous gammaglobulin (IgIV) in these patients as there are few published studies documenting its efficacy.

METHODS

We studied in an open-label protocol 10 adult patients with recurrent respiratory infections and IgG subclass and/or antibody deficiency. All patients received monthly IgIV for 12 months and then were observed for 3 months without IgIV infusions. We studied quality of life, incidence of infections, need for antibiotics, frequency of hospitalizations due to infections, IgG subclass and antibody (tetanus and pneumococcal) levels. Innate immunity was evaluated by studying the status of Toll-like receptors and polymorphisms, mannan-binding lectin levels and genotypes. Correction of the immune defects during IgIV therapy was evaluated.

RESULTS

Monthly IgIV significantly improved quality of life, decreased the number of infections and the need for antibiotics, and improved IgG subclass and antibody serum levels. No consistent finding of innate immunity could be detected.

CONCLUSIONS

IgIV could be beneficial in patients with IgG subclass or antibody deficiency.

Extracellular signal-regulated kinase 1/2 signalling in SLE T cells is influenced by oestrogen and disease activity

Systemic lupus erythematosus (SLE) is an autoimmune disease that occurs primarily in women of reproductive age. The disease is characterized by exaggerated T-cell activity and abnormal T-cell signalling. The mitogen-activated protein kinase (MAPK) pathway is involved in the maintenance of T-cell tolerance that fails in patients with SLE. Oestrogen is a female sex hormone that binds to nuclear receptors and alters the rate of gene transcription. Oestrogen can also act through the plasma membrane and rapidly stimulate second messengers including calcium flux and kinase activation. In this study, we investigated whether oestrogen influences the activation of MAPK signalling through the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in activated SLE T cells. SLE and control T cells were cultured in serum-free medium without and with oestradiol (10(-7) M) for 18 h. The T cells were activated with phorbol 12 myristate 13-acetate and ionomycin for various time points (0-60 min), and the amount of phosphorylated ERK1/2 was measured by immunoblotting. There were no differences in ERK1/2 phosphorylation between SLE and control T cells at 5 and 15 min after the activation stimulus. However, comparison between the amount of phosphorylated ERK1/2 in SLE T cells from the same patients cultured without and with oestradiol showed a significant oestrogen-dependent suppression (P=0.48) of ERK1/2 in patients with inactive/mild systemic lupus erythematosus disease activity index (SLEDAI) (0-2) compared with patients with moderate (4-6) or active (8-12) SLEDAI scores. These results suggest that the suppression of MAPK through ERK1/2 phosphorylation is sensitive to oestradiol in patients with inactive or mild disease, but the sensitivity is not maintained when disease activity increases. Furthermore, studies are now necessary to understand the mechanisms by which oestrogen influences MAPK activation in SLE T cells.

Fulvestrant (Faslodex), an estrogen selective receptor downregulator, in therapy of women with systemic lupus erythematosus. clinical, serologic, bone density, and T cell activation marker studies: a double-blind placebo-controlled trial

OBJECTIVE

Estrogen plays a role in the activation of systemic lupus erythematosus (SLE) and in upregulating intracellular signals by binding to the estrogen receptor(s). Fulvestrant (Faslodex, AstraZeneca Pharmaceuticals, Wilmington, DE, USA), an estrogen selective receptor downregulator, competes for receptor binding in vitro and inhibits estrogen action in target cells. We evaluated the efficacy, side effects, and expression of T cell activation markers, following the administration of fulvestrant or placebo to premenopausal patients with SLE.

METHODS

Twenty women with moderate SLE Disease Activity Index (SLEDAI; 7.87 +/- 3.7) were enrolled. They were premenopausal with regular menstrual cycles and not taking exogenous hormones. The study was double-blind and placebo-controlled. Ten patients received 250 mg fulvestrant intramuscularly for 12 months, and 10 received the placebo. All were observed monthly and 3 months after final fulvestrant/placebo injection. Measures studied were monthly SLEDAI scores, routine and serologic markers for lupus, and serum concentrations of estrogen and fulvestrant. Expression of T cell calcineurin and CD154 mRNA in peripheral T cells was measured by polymerase chain reaction. Medications the patients were taking were recorded each visit. Bone density was obtained at baseline and at visit 12.

RESULTS

Sixteen patients completed the 15-month study, 8 from each group. SLEDAI improved significantly in the fulvestrant group at both 12 months (p = 0.02) and 15 months (p = 0.002), but serologic markers, routine laboratory tests, and bone density did not. Serum estrogen levels were higher in the fulvestrant group and dropped when fulvestrant was discontinued; these differences were not statistically significant. Medications for therapy of lupus to the fulvestrant group were reduced, whereas the placebo group medications were unchanged or increased. Comparison of relative values at individual timepoints revealed significantly lower median values for the T cell activation markers CD154 (p < 0.001) and calcineurin (p = 0.013) in the fulvestrant arm.

CONCLUSION

Blocking estrogen receptors in vivo by an estrogen selective receptor downregulator could be considered as a new and relatively safe therapeutic approach in the management of SLE patients with moderately active disease for the 1-year study period.

Autoimmune lymphoproliferative syndrome in a patient with common variable immunodeficiency: dichotomy of apoptosis

BACKGROUND

Autoimmune lymphoproliferative syndrome (ALPS) is a disorder usually associated with hypergammaglobulinemia and defective apoptosis mostly due to Fas or Fas ligand mutation. Common variable immunodeficiency (CVID) is a disorder with hypogammaglobulinemia commonly associated with increased Fas expression and spontaneous apoptosis.

OBJECTIVE

To describe a patient with a unique combination of hypogammaglobulinemia and ALPS with Fas deficiency but high spontaneous apoptosis.

METHODS

Fas expression on freshly isolated lymphocytes was evaluated by means of immunofluorescence using polyclonal rabbit anti-Fas IgG antibody. Apoptosis of cultured lymphocytes was quantitated using acridine orange and ethidium bromide staining.

RESULTS

We describe a male patient diagnosed as having CVID at the age of 10 years receiving monthly intravenous immunoglobulin. The patient developed ALPS at the age of 21 years manifested by persistent lymphadenopathy and hepatosplenomegaly. The percentage of double-negative T lymphocytes was estimated to be 9%. Freshly isolated lymphocytes showed low Fas expression (3.6% for the patient and 11.2% for the control). The spontaneous apoptosis rate was high (15% for the patient and 5% for the control).

CONCLUSIONS

Autoimmune lymphoproliferative syndrome can be associated with hypogammaglobulinemia and should be looked for in chronic nonmalignant lymphoproliferation in CVID. Common variable immunodeficiency might involve Fas-independent pathways or recruitment of Fas downstream molecules for apoptosis. There is a subset of patients with both CVID and ALPS in whom Fas deficiency could be associated with enhanced spontaneous apoptosis.

Pyogenic arthritis, pyoderma gangrenosum, and acne syndrome (PAPA syndrome) associated with hypogammaglobulinemia and elevated serum tumor necrosis factor-alpha levels

Pyogenic aseptic arthritis, pyoderma gangrenosum, and cystic acne (PAPA) syndrome is an unusual triad that was recently mapped to a chromosome 15q mutation. We describe a patient from this kindred in whom hypogammaglobulinemia and elevated tumor necrosis factor-alpha serum levels were detected. The patient responded well to intravenous gammaglobulin and intra-articular corticosteroid therapy. Immune abnormalities can be found in PAPA syndrome and could be the consequence of the chromosomal abnormalities affecting candidate genes on this chromosome with subsequent abnormalities in cytokine or chemokine secretion. Rheumatologists should be alert for this syndrome. Correction of the immune abnormalities may be effective in controlling the disease manifestations.

Estrogen does not regulate CD154 mRNA stability in systemic lupus erythematosus T cells

Previous studies in our laboratory showed a dose-dependent and hormone-specific increase in CD154 expression in T cells from females with systemic lupus erythematosus (SLE). This present study investigates if the estrogen-dependent increase in CD154 expression is due to stabilization of the messenger RNA. T cells from female SLE patients and controls were cultured for 18 h in serum-free medium without and with estradiol 17-beta (10(-7) M). T cells were either unstimulated (resting) or were activated by further culture on anti-CD3 coated plates. Actinomycin D (25 microg/mL) was added to parallel cultures to inhibit new messenger RNA synthesis. CD154 messenger RNA stability was assessed by reverse-transcription polymerase chain amplification. Resting SLE (n = 10, P = 0.88) and normal (n = 7, P = 0.65) T cells showed no significant differences in message stability in response to estradiol. CD154 messenger RNA was also not significantly stabilized in activated SLE (n = 10, P = 0.15) or activated normal (n = 6, P = 0.077) T cells in response to estradiol. These findings indicate that the estrogen-dependent increase in CD154 in SLE T cells is not due to stability of the mRNA. These data are consistent with the postulate that estradiol stimulates CD154 transcription in SLE T cells.

Differential expression of estrogen receptors in women with systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disease primarily affecting women. T cell activation markers (calcineurin, CD154) increase in SLE T cells cultured with estradiol 17-beta. Biological effects of estradiol are mediated through 2 receptor proteins, estrogen receptor-alpha (ER-alpha) and estrogen receptor-beta (ER-beta). We compared the amount of estrogen receptor subtypes in T cells and measured the ability of receptor agonist-specific ligands to activate marker gene expression.

METHODS

T cells were isolated from 22 female patients with SLE and 17 control women. The amount of ER subtypes was measured by immunoblotting. Some T cells were cultured with ER-alpha or ER-beta-specific agonists. Receptor activation was measured by increased expression of the T cell activation markers CD154 and calcineurin.

RESULTS

Although the amount of ER-alpha appeared to be less in SLE T cells than in control T cells, the difference was not statistically significant (p = 0.081). The quantity of ER-beta was similar in SLE and control T cells. The expression of ER-alpha or ER-beta was independent of menstrual cycle phase, age, or SLE disease activity. Calcineurin and CD154 expression increased in SLE T cells cultured in medium containing ER-alpha and ER-beta agonists.

CONCLUSION

These data indicate that both ER subtypes activate calcineurin and CD154 in SLE but not in normal T cells. Variation in the amount of ER-alpha in SLE T cells suggests this receptor subtype participates in the sensitivity of SLE T cells to estrogen.

Anti-tumor necrosis factor (TNF) therapy in rheumatoid arthritis: correlation of TNF-alpha serum level with clinical response and benefit from changing dose or frequency of infliximab infusions

OBJECTIVE

To determine the relationship between serum TNF-alpha level and clinical response in rheumatoid arthritis patients treated by infliximab. This could be of value to predict clinical response to infliximab and to determine the optimal dose and interval between dosing of infliximab. RA patients who did not respond adequately to conventional doses (3 mg/kg) of infliximab were studied to see if increasing the dose or frequency of infliximab infusions would be more effective.

METHODS

Fifty-five RA patients who fulfilled the American College of Rheumatology criteria and were receiving treatment by anti-TNF-alpha (infliximab 3 mg/kg body weight every 8 weeks) were evaluated by: clinical disease activity using the Richie score index before receiving their scheduled infliximab infusion. Serum level of TNF-alpha, as measured by competitive ELISA assay, was determined immediately before and 9-11 days after receiving infliximab. RA patients who did not respond adequately to treatment with infliximab were given either a larger dose of infliximab or given the infusion at six-week intervals. Their clinical response was then evaluated sixteen months later. RESULTS Patients were divided into 2 groups according to Richie score, active group with score > 10 (score 20.3 +/- 7.7 mean +/- standard deviation, n = 25) and inactive group with scores < or = 10 (score 4.1 +/- 3.2, n = 30). TNF-alpha serum levels pre-infliximab infusion were significantly higher in the active group 76.1 pg/ml than the inactive group 38.0 pg/ml (P < 0.02). Whereas TNF serum level significantly dropped post infliximab in the inactive group (P < 0.05), it did not drop in the active group. The mean level of the post-infusion TNF-alpha serum level was higher (76.6 +/- 93.4 ng/ml) in the-active than the mean level of the post-infusion serum TNF-alpha levels in the inactive group (26.4 ng/ml +/- 7.9) P < 0.01 using the t-test. Increasing the frequency was superior in RA patients' clinical outcome than increasing the dose of infliximab infusions.

CONCLUSION

RA patients who responded well to infliximab and had inactive disease at the time of the study have lower levels of serum TNF-alpha which could be further suppressed by the recommended doses of infliximab. RA patients with active disease have higher serum levels of TNF-alpha which could not be suppressed after the recommended doses of infliximab infusion. Changing the frequency of infliximab infusions in the active group was more effective than increasing the dose of infliximab in inducing improved clinical outcome. We suggest that the lack of suppression of TNF-alpha in the active group could be due to inadequate dosing of infliximab or to the presence of a neutralizing antibody directed against infliximab. It remains to be seen if serum TNF-alpha levels could be used as a guide in determining the dose and intervals between dosing of anti-TNF therapy in RA in order to achieve the desired clinical response.

Increased estrogen-dependent expression of calcineurin in female SLE T cells is regulated by multiple mechanisms

OBJECTIVE

Calcineurin is a key mediator of T cell activation. Previous studies in our laboratory showed a dose-dependent and hormone-specific increase in calcineurin expression in the T cells from females with systemic lupus erythematosus (SLE). This study investigates whether the estrogen-dependent increase in calcineurin expression is due to stabilization of the messenger RNA (mRNA).

METHODS

T cells from female patients with SLE and controls were cultured for 18 hours in a serum-free medium with and without estradiol-17 beta (10(-7) M). Some T cells were activated by further culture on anti-CD3-coated plates. Actinomycin D (25 micrograms/mL) was added to some cultures to inhibit new mRNA synthesis. Calcineurin mRNA stability was assessed by reverse-transcription polymerase chain amplification.

RESULTS

Resting SLE (n = 9, P = .59) and normal (n = 5, P = .90) T cells showed no significant differences in mRNA stability in response to estradiol. Calcineurin mRNA was not significantly stabilized in activated SLE (n = 10, P = .12) or activated normal (n = 8, P = .09) T cells in response to estradiol. However, the amount of calcineurin mRNA stabilized in activated normal T cells (n = 8) was significantly greater (P = .02) compared with SLE T cells (n = 10) only after culture in medium without estradiol.

CONCLUSIONS

These findings highlight the complex gene regulatory mechanisms underlying the differential action of estrogen on SLE T cells. Furthermore, the data indicate that increased calcineurin expression in SLE T cells is not due solely to estrogen-dependent stabilization of the message, and probably involves additional transcriptional regulatory mechanisms.

Vasculitis

Progress has been made in the classification, characterization, and identification of vasculitis; a heterogeneous disease with various vessel sizes and types of involvement. Understanding pathogenetic mechanisms and the kinetics of the inflammatory-immune response is still in its infancy. With the availability of new tools for diagnosis and the use of molecular biological techniques at the cellular, tissue, and fluid phase levels will open the doors for new understanding of the etiology and mechanism(s) of this group of diseases.

Wegener's granulomatosis: survey of 701 patients in North America. Changes in outcome in the 1990s

OBJECTIVE

To study the medical and socioeconomic impact of Wegener's granulomatosis (WG) in a large cohort (n = 701) of patients who are members of the international WG Support Group (WGSG).

METHODS

Forty questions designed and validated by one of the authors and reviewed by the medical consultants of the WGSG International were mailed to 1690 patients with WG who are members of the WGSG; 701 (41%) patients returned the questions. Diagnosis of WG was self-reported for purpose of this questionnaire. Study domains included demographic features, education, analysis of categories of medical care providers, organ system involvement, delay in diagnosis, frequency and sites of biopsies to assist in diagnosis, treatment outcome, familial association, disability, and financial effect. We compared some of these features in patients whose diagnosis was made in the 1970s, 1980s, or 1990s.

RESULTS

In our cohort WG was slightly more prevalent in women (56%), particularly if the disease started at a younger age (9-40 years). Peak age period at disease onset was 45-65 years. Ninety-eight percent of patients were Caucasian. Diagnosis of WG was usually made by a specialist, and the majority of patients received subsequent care by specialists. During the past decade only 7% of patients received a diagnosis of WG upon their first visit to a physician. A period of 3-12 months passed from onset of features of WG to achieving a diagnosis in the majority of patients. Compared to the period 1970-90, in recent years fewer patients had biopsies performed for diagnostic purposes. This observation correlated with increased use of antineutrophil cytoplasmic antibodies. In the 1990s the most common reported therapy was combination of corticosteroids and cyclophosphamide (73%). Patients also reported initial therapy with methotrexate (11%), trimethoprim-sulfamethoxa-zole (32%), and azathioprine (5%). Patients rarely reported other family members with WG. In none of 12 WG patients who had a twin did the twin have WG. The survey did not identify any specific environmental exposure, occupation, or hobby that was overrepresented among patients. One hundred seventy-nine WG patients reported that their disease had a significant financial impact on their lives.

CONCLUSION

Information from this survey of 701 patients is consistent with physician reported data about organ involvement, initial manifestations and therapy, and outcomes in WG. More WG patients in the 1990s were diagnosed after first physician encounter. This survey did not reveal any predisposing or inducing environmental or familial factors, and showed fewer patients become disabled and more were able to work full time.

Estrogen increases CD40 ligand expression in T cells from women with systemic lupus erythematosus

OBJECTIVE

To examine the in vitro effects of estrogen on CD40 ligand (CD40L) expression in peripheral blood T cells isolated from patients with systemic lupus erythematosus (SLE) and normal controls.

METHODS

T cells from female patients with SLE and controls were cultured in serum-free medium without and with 2-fluoroestradiol. Some T cells were activated by further culture on anti-CD3 coated plates. Calcineurin was activated in some T cells by culture in ionomycin. Cell surface CD40L was quantitated by FACS analysis. mRNA expression was measured using semiquantitative PCR.

RESULTS

Lupus T cells cultured in medium containing 2-fluoroestradiol showed a significant (p = 0.04) increase in the amount of CD40L on the cell surface, but not in the number of positive cells, compared to the same T cells cultured without estradiol. Estradiol did not significantly change CD40L expression on the surface of T cells from normal women. In addition, the difference in cell surface CD40L between T cells cultured without and with estradiol was significantly greater (p = 0.048) on SLE than on normal T cells. Culture of SLE T cells in medium containing 2-fluoroestradiol followed by T cell receptor (TCR) activation for 2 h using anti-CD3 resulted in a significant (p = 0.04) estrogen dependent increase in CD40L mRNA. The estrogen dependent increases in SLE T cell CD40L mRNA and cell surface protein were blocked by the estrogen receptor antagonist ICI 182,780. SLE and normal T cells pretreated with estradiol and cultured with ionomycin for 2 h to activate calcineurin showed no significant differences in CD40L mRNA.

CONCLUSION

These results suggest that estradiol, working through the estrogen receptor, stimulates the expression of CD40L in unstimulated and activated SLE T cells. Estradiol effects may be exerted on multiple regulatory steps that control CD40L expression. The estrogen dependent increase in CD40L expression could hyperstimulate SLE T cells and thereby contribute to the pathogenesis of SLE.

In vitro-activated human lupus T cells express normal estrogen receptor proteins which bind to the estrogen response element

We have shown that estrogen receptor (ERalpha, ERbeta) transcripts are expressed in SLE and normal T cells. In this study, T cell nuclear extracts from female lupus patients and normal donors were tested for biologically active ER proteins capable of binding to the human estrogen response element (hERE) by electrophoretic mobility shift assays. When peripheral blood T cells were stimulated with 17beta-estradiol (E2), PMA and ionomycin, two major retarded bands in T cell nuclear extracts exhibited a migration pattern similar to slow migrating protein-ERE complexes in human breast cancer cell extracts. T cells cultured only with E2 did not have these complexes. The formation of the complexes was inhibited by competition with the hERE cold oligonucleotide and partially with anti-ERalpha antibodies. There was no notable difference in the migration pattern of ERE-binding proteins between the SLE and normal T cell extracts. Together, these results suggest that activated human T cells, whether lupus-derived or normal-derived, contain biologically active ERalpha proteins. Other factors may be responsible for differential sensitivity of lupus T cells to estrogen.

Gender differences in autoimmunity: molecular basis for estrogen effects in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that occurs primarily in women (9:1 compared to men). Estrogen is a female sex hormone that acts on target cells through specific receptor proteins and alters the rate of transcription of target genes. Experiments in our laboratory have shown that calcineurin steady-state mRNA levels and phosphatase activity increase when estrogen is cultured with SLE T cells. This estrogen-dependent increase is dose-dependent, hormone-specific and temporally regulated. Estrogen receptor antagonism by ICI 182,780 inhibits the increase in calcineurin mRNA and phosphatase activity, while cycloheximide has no effect suggesting that new protein synthesis is not required. Reverse transcription and polymerase chain amplification indicate that estrogen receptor-alpha and estrogen-beta are expressed in human T cells. However, calcineurin does not respond to estrogen stimulation in T cells from normal females, males and lupus males. Taken together, these results indicate a differential function of the estrogen receptor in women with lupus. A model is proposed that suggests estrogen, acting through the estrogen receptor, enhances T cell activation in women with lupus resulting in amplified T-B cells interactions, B cell activation and autoantibody production.

Molecular mechanisms involved in the estrogen-dependent regulation of calcineurin in systemic lupus erythematosus T cells

Previous experiments in our laboratory indicated that calcineurin expression and PP2B phosphatase activity increased when estrogen was cultured with SLE T cells but not with T cells from normal women. In this report we extended our findings to show that estrogen receptor (ER) antagonism by ICI 182,780 inhibited the estrogen-dependent increase in calcineurin mRNA and phosphatase PP2B activity indicating that estrogen action was mediated through the ER. Inhibition of de novo protein synthesis with cycloheximide suggested that the estrogen-dependent increase in T cell calcineurin mRNA was a direct effect of the ER and new protein synthesis was not required. Estrogen increased calcineurin mRNA in systemic lupus erythematosus (SLE) T cells at 6 h after the start of culture correlating with increased phosphatase activity at this same time. Phosphatase activity increased significantly (P < 0.02) in lupus T cells cultured for 8 h in estradiol-containing medium. Reverse transcription and polymerase chain amplification revealed that ER-beta and ER-alpha were expressed in female and male T cells from SLE patients and normal controls. However, calcineurin steady-state mRNA levels were unaffected by estradiol in cultured T cells from male SLE patients and normal male and female controls. These data indicate that estrogen, bound to the ER, evokes a direct increase in calcineurin expression in T cells from female lupus patients. This gender-specific response suggests that ER function is altered in women with the female predominant autoimmune disease, SLE.

Genome scan of human systemic lupus erythematosus: evidence for linkage on chromosome 1q in African-American pedigrees

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by production of autoantibodies against intracellular antigens including DNA, ribosomal P, Ro (SS-A), La (SS-B), and the spliceosome. Etiology is suspected to involve genetic and environmental factors. Evidence of genetic involvement includes: associations with HLA-DR3, HLA-DR2, Fcgamma receptors (FcgammaR) IIA and IIIA, and hereditary complement component deficiencies, as well as familial aggregation, monozygotic twin concordance >20%, lambdas > 10, purported linkage at 1q41-42, and inbred mouse strains that consistently develop lupus. We have completed a genome scan in 94 extended multiplex pedigrees by using model-based linkage analysis. Potential [log10 of the odds for linkage (lod) > 2.0] SLE loci have been identified at chromosomes 1q41, 1q23, and 11q14-23 in African-Americans; 14q11, 4p15, 11q25, 2q32, 19q13, 6q26-27, and 12p12-11 in European-Americans; and 1q23, 13q32, 20q13, and 1q31 in all pedigrees combined. An effect for the FcgammaRIIA candidate polymorphism) at 1q23 (lod = 3.37 in African-Americans) is syntenic with linkage in a murine model of lupus. Sib-pair and multipoint nonparametric analyses also support linkage (P < 0.05) at nine loci detected by using two-point lod score analysis (lod > 2.0). Our results are consistent with the presumed complexity of genetic susceptibility to SLE and illustrate racial origin is likely to influence the specific nature of these genetic effects.

Gender differences in autoimmune diseases: estrogen increases calcineurin expression in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) predominantly affects women (9:1 compared to men) of childbearing age and often decreases its intensity in postmenopausal women, suggesting that sex hormones play a role in its pathogenesis. Comparison of steady-state levels of calcineurin mRNA using RNase protection assays revealed increased calcineurin expression in response to estradiol in cultured T cells from nine female lupus patients. Calcineurin mRNA levels did not increase significantly in T cells from eight age-matched normal control female volunteers. Estrogen-dependent calcineurin mRNA increased in a dose-dependent fashion, while progesterone and dexamethasone did not increase calcineurin mRNA in patient cells. Lupus T cell calcineurin mRNA increased in response to estradiol at 6 h but not at 3 h. Calcineurin phosphatase activity increased in lupus T cell extracts after incubation of cells with estradiol, while phosphatase activity in normal T cells was unaffected by estrogen. Calcineurin expression in T cells from patients with vasculitis and rheumatoid arthritis taking medications similar to those taken by the lupus patients was unaffected by estradiol. This study provides the first evidence for a molecular marker of estrogen action in lupus patients and suggests that estrogen-dependent changes in lupus T cell calcineurin could alter proinflammatory cytokine gene regulation and T-B cell interactions.

Isolation of anti-nucleosome antibodies from the plasma of lupus nephritis patients

Anti-nucleosome antibodies, which recognise conformational epitopes consisting of histone and DNA in chromatin, have been described in autoimmune diseases. In this study, an attempt was made to isolate anti-nucleosome antibodies from the anti-DNA-depleted plasma IgG of two lupus patients either with or without nephritis by nucleohistone affinity chromatography. The purified nucleohistone-binding antibodies bound to nucleohistone in a specific manner and contained enriched anti-histone antibodies. However, adsorption of the purified antibodies with histone revealed that the nephritis patient-derived antibodies contained nucleohistone-specific antibodies. Although such purified antibodies may not recognise native structures of nucleosomes, this chromatography may provide a method to isolate and determine the fine specificity of anti-nucleosome antibodies in various autoimmune diseases.

Peripheral blood T cells and monocytes and B cell lines derived from patients with lupus express estrogen receptor transcripts similar to those of normal cells

OBJECTIVE

To identify and characterize estrogen receptor (ER) transcripts expressed in immune cells of patients with systemic lupus erythematosus (SLE) and healthy donors.

METHODS

Peripheral blood monocytes and T cells were prepared from patients with SLE (n = 6) and healthy donors (n = 8). T cells were separated into CD4 and CD8. Some monocytes and T cells were stimulated with estradiol, PMA, and ionomycin. Epstein-Barr virus-transformed B cell lines (n = 7) and B cell hybridomas (n = 2) established from patients with SLE and a healthy individual were used as a B cell source. These cells were examined for ER mRNA by reverse transcription nested polymerase chain reaction. Amplified cDNA were sequenced by standard methods.

RESULTS

In all cells tested, ER mRNA was expressed without prior in vitro stimulation. Partial sequences from exons 1-8 were nearly identical to the published sequence of the human ER mRNA. There were no notable differences in the ER transcripts between patients and healthy controls. Variant receptor transcripts lacking exon 5 or exon 7, which encodes the hormone binding domain, were identified in the majority of the cells. Precise deletion of the exons suggests that they are alternatively spliced transcripts. Whether the detected transcripts are translated into functional receptor proteins remains to be determined. In vitro stimulation did not affect ER mRNA expression. The presence of variants did not correlate with disease activity or medication.

CONCLUSION

Monocytes, T cells, and B cells in patients express transcripts of the normal wild type ER and the hormone binding domain variants in vivo.

V gene sequences of lupus-derived human IgM anti-ssDNA antibody: implication for the importance of the location of DNA-binding amino acids

Binding and structural characteristics of human IgMk anti-ssDNA antibody 7B3 were determined. 7B3 was derived from Epstein-Barr virus-transformed peripheral blood B cells of a lupus nephritis patient. Purified 7B3 bound ssDNA from various species, but not dsDNA or structurally unrelated antigens. The relative avidity of 7B3 was high in comparison with IgM anti-DNA antibodies previously described by other investigators. Sequence analysis showed that 7B3 used VH26/D35/JH3 and Humkv328h5/JK1 germline genes, and had a few mutations in the complementarity determining regions (CDRs). No arginine was expressed in the heavy-chain CDR3. However, the putative DNA contact sites, based on the previous crystallographic and computer modeling studies, were occupied by mutated or germline-derived basic and polar amino acids. These results suggest that a minimally mutated IgM anti-ssDNA antibody with a paucity of arginines could display monospecificity and high avidity if DNA-binding amino acids are enriched at the critical DNA contact sites.

Estrogen decreases in vitro apoptosis of peripheral blood mononuclear cells from women with normal menstrual cycles and decreases TNF-alpha production in SLE but not in normal cultures

Estrogen has been suspected of causing changes in the lupus disease process by an as yet undetermined mechanism. In vitro apoptosis of peripheral blood mononuclear cells (PBMCs) in short-term unstimulated cultures of systemic lupus erythematosus (SLE) cells is accelerated compared to that in cells from normal individuals. To determine whether estrogen might be involved in regulating the rate of apoptosis in lupus, PBMCs or T cells from women with or without normal menstrual cycles were cultured for 16-20 hr with or without 30 ng/ml estradiol. The rate of apoptosis of the cells was measured, and supernatants of these cultures were tested for various cytokines known to affect apoptosis directly or indirectly. Compared to untreated cultures, estrogen significantly reduced in vitro apoptosis of both patient (P < 0.05, n = 12) and normal (P < 0.001, n = 14) PBMCs if the donors had normal menstrual cycles. Estrogen did not decrease apoptosis of noncycling patient (n = 8) nor of normal (n = 11) cells. Apoptosis of T cells cultured alone was not affected by estrogen. Supernatants from patients' estrogen-treated PBMCs had significantly less TNF-alpha than untreated cultures (P < 0.05, n = 12). TNF-alpha levels from normals' cell cultures were unchanged. Changes in hormone status (hysterectomy or menopause) alter estrogen-sensitive apoptosis, which may be mediated through monocytes. Estrogen-induced decreases in apoptosis combined with decreased TNF-alpha production in the presence of estrogen may allow survival of auto-immune cells in SLE patients.

Presence of a variant form of the estrogen receptor in peripheral blood mononuclear cells from normal individuals and lupus patients

Estrogen may participate in the pathogenesis of systemic lupus erythematosus (SLE) via its intracellular receptor. To investigate the presence of various isoforms of the estrogen receptor (ER) in SLE we isolated RNA from mononuclear cells of lupus patients and normal controls. Using RT-PCR we were able to identify both the full length wild-type form and an isoform of the ER which precisely lacks exon V in both patient and normal individuals. Our results, although limited, suggest that normal individuals can express both the wild-type and truncated version at the same time, whereas lupus patients only express either the wild-type or the truncated ER. This finding may lead to a better understanding of the reasons for the prevalence of lupus in females and of the estrogenic effects on SLE disease activity.

Binding affinity and quantity of estrogen receptor in peripheral blood monocytes of patients with systemic lupus erythematosus

Binding affinity and quantity of the estrogen receptor in monocytes of patients with systemic lupus erythematosus (SLE) were studied. The tritiated-estradiol binding assay was performed using peripheral blood adherent cells (> 95% monocytes) derived from six lupus patients (SLEDAI score: 2-30) and five age-comparable normal women during the mid-follicular phase of the menstrual cycle. Dissociation constant (Kd) and number of binding sites (Ro) were estimated by Scatchard analysis. The specificity and sensitivity of the assay were verified by using estrogen receptor-positive ZR75-1 human breast cancer cells. Kd and Ro of the type I receptor for the SLE patients were 12.2 +/- 6.5 (nM) and 69.0 +/- 42.4 (x 1000/cell), respectively, while those of the normals were 14.5 +/- 3.7 and 86.8 +/- 23.4, respectively. Three patients displayed relatively low Kd or Ro values. While those low values fell within the mean -3s.d. of the normal controls, precise statistical comparison was not possible. No clear correlation between the receptor parameters and the SLEDAI scores was noted. Although further studies of a larger number of samples are needed to conclude, these results suggest that peripheral blood monocytes of SLE patients express the estrogen receptor whose Kd and Ro are similar to those of normals.

Anti-(DNA-histone) antibodies in active lupus nephritis

OBJECTIVE

To detect and characterize anti-(DNA-histone) antibodies in patients with active lupus nephritis.

METHODS

Calf thymus double stranded DNA was reassociated with histone in vitro. Polynucleosomes were prepared from chicken erythrocyte nuclei, calf thymus nucleohistone, and human peripheral blood mononuclear cells. Anti-DNA activity was depleted from purified IgG using DNA-cellulose. Binding of the adsorbed IgG to various (DNA-histone) related antigens was measured by ELISA. Antigen specificity was assessed by inhibition assays and adsorption studies using histone and nucleosome conjugated sepharose beads.

RESULTS

Anti-(DNA-histone) antibodies were detected in 3 of 5 patients with active lupus nephritis. They specifically recognized determinants consisting of both DNA and histone, but not DNA or histone alone. Anti-(DNA-histone) antibodies largely overlapped with antinucleosome antibodies and appeared to react with nucleosomes released by apoptotic human mononuclear cells.

CONCLUSION

Anti-(DNA-histone) antibodies are present in active lupus nephritis and largely represent antinucleosome antibodies. They may contribute to the pathogenesis of nephritis by forming immune complexes with apoptosis related nucleosomes.

V gene sequences of human anti-ssDNA antibodies secreted by lupus-derived CD5-negative B cell hybridomas

V gene sequences encoding two lupus-derived human monoclonal IgMk anti-ssDNA antibodies (2F7 and 1A6) and CD5 mRNA expression by the corresponding hybridomas were investigated. Both antibodies displayed V gene sequences nearly in germline configuration compared with their putative germline counterparts. It appeared that 2F7 used hv3019b9/HUD-3/JH6 and 12La/Jk2, while 1A6 utilized HHG19/D31-HUD-3/JH2 and Humkv328h5/Jk1. Assessment of R/S mutation ratios suggested that 2F7 and 1A6 have not undergone the antigen-driven somatic mutation. The HCDR3 featuring arginine appeared to be important in determining the anti-ssDNA specificity. CD5 mRNA was negative in both hybridomas. Since 2F7 was previously shown to be monospecific and of high affinity, these results provide the molecular basis of such unique immunochemical characteristics of the IgM anti-ssDNA antibody. Germline V genes and N sequences may be selected to confer such anti-ssDNA specificity during V gene rearrangement, which might involve CD5-negative B cells.

Heparan sulphate-ELISA gives false positive results for anti-DNA-DNA/histone immune complexes in sera of patients with SLE

Heparan sulphate-reactive antibodies in lupus sera have been suggested to be anti-DNA-DNA/histone immune complexes and to be associated with lupus nephritis. In this study, 23 anti-DNA-positive lupus sera including 13 active nephritis sera were tested for the presence of circulating anti-DNA-DNA/histone immune complexes by solid phase heparan sulphate-ELISA. Because of high background binding to protamine chloride-linked heparan sulphate plates, poly-L-lysine (PLL) was used as a linker and the remaining active sites of PLL were blocked with poly-L-glutamic acid. The ELISA was capable of detecting small amounts of anti-DNA IgG-DNA/histone immune complexes formed in vitro. However, only three active nephritis sera of the 23 sera tested showed significant binding to heparan sulphate plates. This binding was found to be non-specific, the result of high background binding of IgG to PLL. Anti-heparan sulphate ELISA using positively charged linkers detects non-specific binding when lupus sera are tested. Specific assays need to be developed for DNA/histone-related immune complexes present in lupus sera.

Anti-interleukin-6 and soluble interleukin-6 receptor in systemic lupus erythematosus

IL-6, soluble IL-6 receptor and IgG with anti-IL-6 activity were measured in the plasma of 14 lupus patients and 10 normal subjects. The capacity of peripheral blood mononuclear cells to spontaneously produce IL-6 in vitro was also measured. Our results indicate that IL-6 plasma levels in patient plasma as measured by ELISA were not different from normal but that supernatant levels were significantly lower than normal (P < 0.05). In vitro IgG production was comparable for all lupus patients' cells irrespective of the in vitro IL-6 levels. Plasma soluble IL-6 receptor levels directly correlated with IL-6 production capacity of SLE cells and the ratio of soluble receptor to anti-IL-6 directly correlated with IL-6 production in patients but not in normals. Inhibition assays demonstrated competition between anti-IL-6 and soluble receptors for IL-6 and the inhibition by plasma of IL-6 binding to monoclonal anti-IL-6. We believe the interaction of anti-IL-6 and IL-6 receptor with IL-6 may contribute to the homeostasis in IL-6 activity in vivo and skewing of the soluble receptor/anti-IL-6 ration may contribute to the lupus disease process.

Cationic and high affinity serum IgG anti-dsDNA antibodies in active lupus nephritis

To investigate differences between cationic anti-dsDNA antibodies during active and inactive nephritis, low- and high-affinity IgG anti-dsDNA antibodies were prepared from sera of a lupus patient and compared for their binding affinity, spectrotype, and idiotype expression. The ratio of high-affinity to low-affinity anti-DNA antibodies and the relative avidity of the high-affinity anti-DNA antibodies decreased when active nephritis became inactive. Isoelectric focusing showed that cationic anti-dsDNA populations were present predominantly in the high-affinity fraction during active nephritis and in the low-affinity fraction during inactive nephritis. Idiotypic analysis by ELISA and Western blotting showed that the high-affinity cationic anti-DNA antibodies during active nephritis were idiotypically different from their low-affinity counterparts during inactive nephritis. The differences in binding affinity and idiotypy of the cationic anti-dsDNA antibodies suggest that certain serum IgG anti-dsDNA antibodies with both cationic charge and high affinity may be associated with active nephritis.

In vitro modulation of anti-DNA secreting peripheral blood mononuclear cells of lupus patients by anti-idiotypic antibody of pooled human intravenous immune globulin

Anti-idiotypic antibody and its F(ab')2 fragments prepared from pooled normal human IgG had a partial inhibitory effect on the spontaneous in vitro secretion of anti-DNA antibodies from blood mononuclear cells of lupus patients. The inhibitory effect was specific for anti-DNA secretion as the anti-idiotype failed to inhibit the spontaneous secretion of anti-tetanus toxoid in the same culture supernatants. Non-anti-DNA IgG or its F(ab')2 fragments from pooled normal human IgG had less inhibitory effect on anti-DNA secretion than the purified anti-Id. In vitro polyclonal IgG secretion by lupus blood mononuclear cells was equally inhibited by both the anti-idiotype and the non-anti-DNA IgG of pooled normal human IgG. There was no correlation between the in vitro suppression of anti-DNA and that of total IgG or of anti-tetanus toxoid antibody. Pooled normal human IgG could have a potential beneficial effect in the therapy of systemic lupus erythematosus by inhibiting anti-DNA production via an anti-idiotypic mechanism.

Lupus-derived human monoclonal IgM anti-DNA antibody displays monospecificity, high affinity and private idiotype specificity

A human monoclonal IgM k anti-DNA antibody, designated 2F7, was prepared by somatic hybridization of peripheral blood lymphocytes from a lupus patient with a human-mouse heterohybridoma cell line, K6H6/B5. 2F7 was tested for its antigen binding and idiotypic specificity by direct binding and inhibition enzyme-linked immunosorbent assays. 2F7 had a high binding activity to single-stranded DNA (ssDNA) but not to double-stranded DNA. It cross-reacted with single-stranded homopolymers with pyrimidine bases and double-stranded polynucleotides containing those homopolymers, suggesting that 2F7 recognizes a conformational determinant made up of both deoxyribose-phosphate backbone and specific nucleotide base. 2F7 did not cross-react with eight structurally unrelated self-antigens. Dissociation constant (Kd) of 2F7 for sonicated ssDNA was approximately 4.5 x 10(-9) M, indicating its relatively high affinity. Idiotypic characterization with rabbit anti-idiotype raised against 2F7 suggested that 2F7 expressed an idiotype at or near its antigen-binding sites that was not detected in sera from 20 unrelated lupus patients, 10 lupus family members and 10 normal individuals. These results suggest that certain IgM class anti-DNA antibodies in human systemic lupus erythematosus may arise by antigen stimulation and not simply by polyclonal B-cell activation.

Expression of inactive stage anti-dsDNA idiotypes on anti-ssDNA antibodies in a lupus patient during active stage of lupus cerebritis

The possibility that idiotypes (Ids) defined on anti-double stranded DNA (dsDNA) antibodies during active and inactive stages of lupus (1/84 Id and 4/90 Id, respectively) were expressed on anti-DNA antibodies during a subsequent active period (9/90) of the disease was investigated in a lupus patient with lupus cerebritis. Using rabbit (R)-anti-Ids specific to 1/84 Id and 4/90 Id in inhibition assays, the 4/90 Id was shown to be expressed on the framework regions of anti-single stranded DNA (ssDNA) but poorly on co-existing anti-dsDNA antibodies of active (9/90) stage. The 1/84 Id was poorly expressed on both types of 9/90 anti-DNA antibodies. While the 9/90 anti-ssDNA significantly bound to immobilized ssDNA and several single-stranded polynucleotides, only ssDNA inhibited the binding of the anti-ssDNA to ssDNA, suggesting its monospecificity toward ssDNA. Western blot analysis following isoelectric focusing showed that a spectrotype pattern of 4/90 Id-positive 9/90 anti-ssDNA IgG was similar to that of the 4/90 anti-dsDNA, suggesting that they are of related clonal origin. The present study suggests the idiotypic heterogeneity of anti-DNA antibodies and the shift of antigen specificity within an idiotypically related anti-DNA population during exacerbation of the disease.

Shift of private and not of cross-reactive anti-DNA idiotypes in systemic lupus erythematosus

The shift of private idiotype (Id) and cross-reactive Id (CRI) on anti-DNA antibodies in a lupus patient KE was investigated during a 7-year period. Anti-private Id and anti-CRI activities were separated by affinity chromatography from rabbit (R)-anti-Ids raised against KE anti-DNA antibodies during active (1/84) and inactive (4/90) stages of the disease. Anti-CRI isolated from the 84 R-anti-Id appeared to recognize binding site-related Ids that are shared with KE non-anti-DNA antibodies, unrelated lupus patients' sera, and certain normal sera. Id expression on serial serum samples of KE using these fractionated R-anti-Ids as probes showed that the 1/84 private Id expression declined while the 4/90 private Id expression gradually increased. Expression of the CRI showed a relatively stable pattern. These results suggest that anti-DNA populations detected by anti-private Id can shift, while populations expressing CRI may stay stable.

Idiotypic and immunochemical differences of anti-DNA antibodies of a lupus patient during active and inactive disease

IgG anti-DNA antibodies of a lupus patient during active and inactive stages of her disease were studied. There were no significant differences in the amounts, in double-stranded DNA-binding activity, or in complement-fixing ability between purified IgG anti-DNA antibodies of both stages. However, their idiotype (Id) expressions were different as revealed by binding to rabbit anti-Ids raised against each of the anti-DNA antibodies. Moreover, the active stage anti-DNA antibodies had higher activity and less cross-reactivity with polynucleotides. Dominant anti-DNA populations during the active and inactive stages of systemic lupus erythematosus are clonally and qualitatively different.

Detection and purification of antiidiotypic antibody against anti-DNA in intravenous immune globulin

Pooled normal human IgG for therapeutic use, following depletion of anti-DNA, anti-Fc, and anti-F(ab')2 of normal IgG, expressed antiidiotypic activity against anti-DNA derived from lupus sera. The antiidiotype enriched by elution from anti-DNA affinity columns bound directly to anti-DNA IgG and inhibited the binding of lupus sera to DNA but did not bind to normal IgG or inhibit the binding of anti-tetanus toxoid to tetanus toxoid. Antiidiotypes in pooled normal sera may have a role in the clinical improvement seen in patients with autoimmune diseases receiving intravenous immune globulin.

Immunoregulation of anti-islet cell antibody in insulin-dependent diabetes: failure to detect anti-idiotypic antibody following seroconversion

A search was made for the presence of spontaneous auto-anti-idiotype in sera of three insulin-dependent diabetics when they converted from islet cell antibody positive to islet cell antibody negative states. Rabbit anti-idiotype specific for islet cell antibody was used as the positive control. Using an enzyme-linked immunoabsorbent assay, binding of the rabbit anti-idiotype to idiotype-coated plates could not be inhibited by islet cell antibody negative sera. Using this same assay, there was no significant difference in the binding of islet cell antibody positive or negative sera to either idiotype-coated or normal IgG-coated plates. Binding of islet cell antibody to pancreatic sections could not be inhibited by islet cell antibody negative sera in an immunofluorescent assay. Network regulation by auto-anti-idiotype does not seem to play a role in the decline or absence of islet cell antibody in the early phases of insulin-dependent diabetes mellitus.

Lack of correlation between HLA types and anti-idiotypic production in family members of a lupus patient

Correlations of anti-single-stranded (ss) DNA, anti-F(ab')2, and anti-idiotypes to HLA types of 16 healthy family members of a lupus patient were studied. High levels of anti-ss DNA (63%) and anti-F(ab')2 (69%) were detected. Of the 12 family members who expressed HLA-DR2 antigen, 8 had anti-ss DNA and anti-F(ab')2 antibodies. One out of 3 family members who shared the same HLA phenotypes, A1B8DR2, of the proband had high levels of anti-idiotype directed against the proband's F(ab')2 anti-DNA. Though a high prevalence of A1B8DR2, of anti-ss DNA, and of anti-F(ab')2 in healthy family members of a lupus patient was found, anti-idiotypes against anti-DNA were not dependent on HLA-A, B, Dr.

Effect of in vitro ultraviolet radiation on the binding capacity of anti-DNA and DNA in systemic lupus erythematosus

The in vitro effects of various doses of ultra violet A (UVA) or UVB irradiation on DNA or anti-DNA as measured by their subsequent binding to anti-DNA or DNA were examined. Sera from 12 patients with active lupus were studied. UVA irradiation at 20-240 J/m2 or UVB irradiation at 2-24 J/m2 did not affect DNA or anti-DNA binding to anti-DNA or DNA, respectively. Modulation of the UV effect on DNA and anti-DNA by adding methylprednisolone, hydroxychloroquine and indomethacin at 10(-6) M did not alter the UV effect. UV light does not exert its effect directly on the binding of anti-DNA to DNA.

Characterization of two anti-DNA antibodies bearing distinct idiotypes. Correlation with clinical manifestations

Spontaneous idiotype shift of anti-DNA antibodies in systemic lupus erythematosus was shown to be associated with changes in the clinical manifestations of the disease. Characterization of two anti-DNA antibody preparations from the same lupus patient showed that lupus nephritis was associated with antibodies showing higher specific antigen-binding activity and avidity to DNA and presenting more cationic quality upon isoelectric focusing and Western blot analysis than the ones found in patients without renal involvement. Lupus cerebritis was associated with anti-DNA antibodies with different idiotypic characteristics not shared by anti-DNA antibodies present in lupus nephritis. Lupus cerebritis anti-DNA antibodies had less specific antigen-binding activity and avidity to DNA and did not show cationic quality. Idiotypic and immunochemical changes of anti-DNA antibodies in lupus may be associated with various clinical manifestations.

Antiidiotypic antibodies against anti-DNA antibodies in sera of families of lupus patients

We searched for antiidiotypes directed against anti-DNA in sera of healthy family members of lupus patients. Controls were healthy individuals without a personal or family history of lupus. No significant differences were noted between the family members' and the control group's sera with respect to binding to DNA or to non-anti-DNA F(ab')2 fragments. Family members' sera had higher binding to anti-DNA F(ab')2 and to normal IgG F(ab')2 fragments (P less than 0.01). Sera of the family members had significantly higher binding to anti-DNA F(ab')2 than to normal IgG F(ab')2 fragments (P less than 0.0036). Inhibition experiments have shown that the antiidiotype is directed against the framework determinants and not against the antigen binding sites of the idiotype. The antiidiotypic antibodies were directed against cross-reactive anti-DNA idiotypes and were not restricted to the idiotypes of the lupus proband. Age, sex, and blood relationship to the lupus patient did not influence the presence of antiidiotypes in the family members. The possible role of environmental factors in the induction of antiidiotypes and the role of the latter in regulating anti-DNA antibodies are discussed.

Private idiotypes on human polyclonal IgG anti-DNA antibodies are not expressed on coexisting IgM anti-DNA antibodies in systemic lupus erythematosus

Sharing of private idiotypes (Id) on human polyclonal IgG anti-double-stranded DNA (dsDNA) with coexisting IgM anti-dsDNA was investigated using rabbit (R) anti-Id raised against IgG anti-dsDNA. The R-anti-Id showed specificity to private Id in or near the antigen-binding sites. The R-anti-Id poorly bound to the immobilized enriched IgM anti-dsDNA preparation but significantly bound to IgG anti-dsDNA preparation by a direct-binding ELISA (0.020 OD vs 0.295 OD, respectively). The R-anti-Id poorly inhibited the binding of IgM anti-dsDNA to immobilized dsDNA but significantly inhibited the binding of IgG anti-dsDNA to dsDNA (6% vs 55% inhibition, respectively). This was confirmed by poor inhibition of binding of the R-anti-Id to immobilized IgG anti-dsDNA by the enriched IgM anti-dsDNA preparation (maximum of 26% inhibition at 50 micrograms/ml). Nonsharing of private Id between IgG and coexisting IgM anti-dsDNA may represent the idiotypic diversity of human anti-DNA antibodies secondary to the frequent occurrence of somatic mutation on anti-DNA antibody during class switching.

Spontaneous shift of anti-DNA antibody idiotypes in systemic lupus erythematosus

Spontaneous shift in Id expression of polyclonal anti-DNA antibodies in a patient, BS, with SLE was investigated. BS had active lupus nephritis in 1982 and developed central nervous system lupus in 1986 without evidence of active nephritis. Two rabbit polyclonal anti-Id (BS-82 and BS-86 R-anti-Id) were raised against affinity-purified anti-DNA antibodies prepared from 1982 serum (BS-82) and 1986 serum (BS-86), respectively. In addition, murine monoclonal anti-Id was prepared against BS-82 Id. Direct binding assays showed that all three anti-Id had preferential binding to the immunizing anti-DNA antibodies (the homologous Id) and poor binding to anti-DNA antibodies prepared from the different dated sample of BS. This was confirmed by inhibition assays of binding of anti-Id to the homologous Id by various Id. Moreover, inhibition assays of binding of various Id to DNA by the R-anti-Id showed that the R-anti-Id was the most effective inhibitor for the homologous Id. Testing for Id expression in serial (1982 to 1986) serum samples of BS with the R-anti-Id as probes showed that BS-82 Id declined and was undetectable after October, 1984, whereas BS-86 Id was first detectable in July, 1985, and increased by June, 1986. These results clearly demonstrate spontaneous shifts in Id expression of human anti-DNA antibodies. The phenomenon of Id shift should be considered in any future strategy for the diagnosis and therapy of human autoimmune disease by anti-Id.