Lupus subsets: relationship to genetic and environmental factors

Purified protein derivative reaction in systemic lupus erythematosus patients. Indirect study of cellular immunity

Cutaneous anergy in SLE patients results from disease activity and/or immunosuppressive treatment (IT). The aim of this study was to evaluate purified protein derivative (PPD) reaction in SLE patients. A total of 145 patients and 20 controls were studied. Five units of PPD were applied on day 0, and skin reaction was measured after 3 (PPD1) and 6 (PPD2) days. A booster was applied (day 14), and the reaction was measured after 3 (PPD3) and 6 (PPD4) days. Non-parametric ANOVA test and unpaired Student's t-test were performed. Forty patients (group I) were inactive (MexSLEDAI < 3), receiving no IT (at least 3 months previous to the PPD test); 39 (group II) were inactive receiving IT; 24 (group III) were active without IT, and 42 (group IV) were active with IT. Active patients had lower PPD1 (group III, 1.4 +/- 0.9; group IV, 0.6 +/- 0.5) than inactive patients (group I, 8.4 +/- 2.3; group II, 5.1 +/- 1.9) and than controls (9.4 +/- 3; P < or = 0.001). Group IV had lower delayed response (PPD2 = 0.3 +/- 0.3) than inactive groups (group I, 2.6 +/- 0.9; group II, 3.1 +/- 0.8) and than controls (7.9 +/- 2.5; P < or = 0.001). Group III had lower delayed reaction (PPD2 = 1.2 +/- 0.8) than controls (P < or = 0.001). Active SLE patients, receiving or not receiving IT, had lower skin response to PPD than inactive patients and controls.

A susceptibility locus for human systemic lupus erythematosus (hSLE1) on chromosome 2q

To identify chromosomal regions containing susceptibility loci for systemic lupus erythematosus (SLE), we performed genome scans in families with multiple SLE patients from Iceland, a geographical and genetic isolate, and from Sweden. A number of chromosomal regions showed maximum lod scores (Z) indicating possible linkage to SLE in both the Icelandic and Swedish families. In the Icelandic families, five regions showed lod scores greater than 2.0, three of which (4p15-13, Z=3.20; 9p22, Z=2.27; 19q13, Z=2.06) are homologous to the murine regions containing the lmb2, sle2 and sle3 loci, respectively. The fourth region is located on 19p13 (D19S247, Z=2.58) and the fifth on 2q37 (D2S125, Z=2.06). Only two regions showed lod scores above 2.0 in the Swedish families: on chromosome 2q11 (D2S436, Z=2. 13) and 2q37 (D2S125, Z=2.18). The combination of both family sets gave a highly significant lod score at D2S125 of Z=4.24 in favor of linkage for 2q37. This region represents a new locus for SLE. Our results underscore the importance of studying well-defined populations for genetic analysis of complex diseases such as SLE.

Identification of patient subsets among those presumptively diagnosed with, referred, and/or followed up for systemic lupus erythematosus at a large tertiary care center

OBJECTIVE

To identify different subsets of patients from a large tertiary care center who were presumptively referred for and/or diagnosed with systemic lupus erythematosus (SLE) (or followed up).

METHODS

All patients who were referred, followed up, and/or diagnosed with SLE at our center, who had disease duration of < or = 5 years, and who resided in Alabama, were identified and their charts reviewed and abstracted.

RESULTS

Abstracted data were reviewed by 3 rheumatologists, and patients were assigned to 1 of 3 categories: 1) SLE by the American College of Rheumatology (ACR; formerly, the American Rheumatism Association) criteria, 2) clinical SLE but not meeting 4 of the ACR criteria, or 3) fibromyalgia-like manifestations with antinuclear antibody (ANA) positivity. There were 90 patients in the first group (criteria), 22 in the second group (clinical), and 37 in the third group (fibromyalgia-like). Patients in all 3 groups were predominantly women. Only 5% of the fibromyalgia-like group were African-American, compared with 55-65% for the other 2 groups. Organ system involvement occurred with comparable frequency in the first 2 groups, but mucocutaneous and hematologic abnormalities were more frequent in the criteria group; in contrast, the patients with fibromyalgia-like symptoms primarily presented with arthralgias/myalgias, fatigue, depression, and sleep disturbances, as well as mucocutaneous manifestations.

CONCLUSION

When the ACR criteria for SLE are used to determine eligibility for lupus studies, a group of patients with clinically unequivocal SLE are excluded. A group of patients with fibromyalgia-like manifestations, who test positive for ANA and differ clinically and sociodemographically from the patients in the other 2 groups, very likely do not belong within the spectrum of SLE.

Preliminary classification criteria for the antiphospholipid syndrome within systemic lupus erythematosus

Ten percent of 667 consecutive systemic lupus erythematosus (SLE) patients were considered to have definite antiphospholipid syndrome (aPLS) because they had two or more antiphospholipid (aPL)-related clinical manifestations and aPL titers more than 5 SD above the mean of normal controls. Another 14% had either one aPL-related manifestation but high titers of the antibody or two manifestations and low aPL titers (probable aPLS). One fourth of the patients had no manifestations but high titers, one manifestation and low titers, or two or more manifestations and negative aPL titers ("doubtful" aPLS); the other half were considered negative for aPLS. In patients with high-titer aPL, the number of aPL-related manifestations was influenced by disease duration and number of pregnancies, indicating potential mobility of category with time or with risk of recurrent pregnancy loss. Patients with two or more manifestations but variable aPL levels differed in immunosuppressive treatment and in the number of times they had been tested, indicating potential mobility of category with lower treatment and/or further aPL testing. Patients with definite aPLS had increased risk of cutaneous vasculitis, peripheral neuropathy, seizures, psychosis, transient ischemic attacks, and leukopenia. In 11 of 52 SLE patients with definite aPLS the initial manifestation was related to aPL, and in 16 it concurred with an unrelated one. Only two patients fulfilled criteria for aPLS before having other evidence of SLE. The authors conclude that aPLS occurring within SLE is part of the disease rather than an associated condition and propose the use of definite and probable classification categories. These criteria, with appropriate follow-up and clinical and serological exclusion clauses for potential primary conditions, could also be applied to primary aPLS.

1-Phenyl-5-vinyl-2-imidazolidinethione, a proposed causative agent of Spanish toxic oil syndrome: synthesis, and identification in one of a group of case-associated oil samples

A method is described for the synthesis and characterization of N-(2-hydroxy-3-butenyl)-N'-phenylthiourea, and its cyclization product, 1-phenyl-5-vinyl-2-imidazolidinethione (PVIZT). Fourteen coded oil samples associated with toxic oil syndrome cases in Spain were examined by gas chromatography-electron impact mass spectrometry for the presence of PVIZT. Although these samples were obtained from households where cases of toxic oil syndrome had been recorded, they differed extremely with regard to their anilide and sulphur contents. In one sample PVIZT was detected at an estimated concentration of 1 mg/kg.

Chemical-induced autoimmune reactions and Spanish toxic oil syndrome. Focus on hydantoins and related compounds

Autoimmune diseases comprise a wide spectrum of overlapping, systemic and organ-specific disorders. Although, etiology and pathogenesis of such disorders are largely unknown, endogenous host factors and exogenous agents, such as viruses, bacteria, and small molecular weight chemicals, drugs and food components, are believed to be involved. The toxicological significance of low molecular weight compounds on induction of autoimmune disorders is illustrated by the toxic oil syndrome (TOS), a chemically induced epidemic, observed in Spain since 1981. The causative chemical(s) of TOS is still elusive, but an association between ingestion of refined aniline-adulterated rapeseed oil and the syndrome is well-documented. Epidemiological, clinical and immunopathological symptoms of TOS are briefly reviewed. The striking resemblance with immunological disorders, observed in man upon medication with hydantoins and related compounds, is demonstrated. The likeliness of formation of a hydantoin-related compound in the aniline-adulterated oil is evidenced and its role as possible toxic agent in TOS is proposed. Further, the presence of hydantoins and related compounds in food is briefly reviewed and it is suggested that these chemicals may account for a portion of idiopathic autoimmune diseases observed in man. The need for development of animal models to assess this kind of immunotoxicological effects is stressed.

Enzyme-linked immunosorbent assays for antibodies to poly(A), poly dAT and histones: possibly useful tools for the evaluation of prognosis and disease activity in systemic lupus erythematosus

In a prospective study 222 sera from 56 patients with systemic lupus erythematosus (SLE) were tested for antibodies to poly(A), poly dAT and histones using enzyme-linked immunosorbent assay (ELISA). Patients with active disease had significantly more often antibodies to poly(A), poly dAT and histones than patients with inactive disease. There was a positive correlation between the activity score of the disease and the levels of poly(A)-antibodies of IgG and IgM class, poly dAT-antibodies and antibodies to histones. Patients with SLE-nephritis had a higher level of poly dAT and IgG class poly(A) antibodies than patients without nephritis. Interestingly, patients with an SLE-nephritis had lower levels of IgM-poly(A)-antibodies than those without nephritis. Attempts to use the ELISAs in predicting the SLE exacerbations were unsuccessful. However, the assays can be used as parameters in the estimation of the disease activity.

Circulating DNA-antibodies in systemic lupus erythematosus

Sera from 57 patients with systemic lupus erythematosus (SLE) were tested for DNA-antibodies by three different methods: a radioimmunological test using the Farr technique, the Crithidia luciliae immunofluorescence assay for anti-double-stranded (native) DNA (anti-ds-DNA), and a solid-phase immunoenzymatic assay for anti-single-stranded (denatured) DNA (anti-ss-DNA) of IgG and IgM classes. There was a positive correlation between the activity of the disease and the levels of ds-DNA-antibodies and IgG anti-ss-DNA. Patients with active nephritis had a higher amount of anti-ds-DNA and anti-ss-DNA of IgG class than patients with inactive nephritis (P less than 0.05 and 0.01, respectively). Patients with SLE nephritis had lower levels of ss-DNA-antibodies of IgM class than patients without nephritis (P less than 0.02). There was a positive correlation between the IgG-anti-ss-DNA/IgM-anti-ss-DNA ratio and the activity score of the disease. These results suggest that the anti-ss-DNA assay may be useful in the follow-up of SLE. Complement fixing anti-ds-DNA and the highest levels of anti-ds-DNA by Farr assay were usually associated with an active disease, especially nephritis and joint involvement.