Role of serum autoantibodies in blood brain barrier damages in neuropsychiatric systemic lupus erythematosus

OBJECTIVES

The present study was carried out to elucidate the roles of serum autoantibodies in the development of blood-brain barrier (BBB) damages in neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Paired serum and CSF samples were obtained from 101 SLE patients when they presented active neuropsychiatric manifestations (69 patients with diffuse psychiatric/neuropsychological syndromes [diffuse NPSLE] and 32 patients with neurologic syndromes or peripheral neuropathy [focal NPSLE]). IgG anti-NR2 subunit of NMDA receptor (anti-NR2), anti-Sm, anti-ribosomal P and IgG anti-cardiolipin in sera and albumin in CSF and sera were measured by ELISA. Blood-brain barrier (BBB) function was evaluated by Q albumin (CSF/serum albumin quotient x 1,000).

RESULTS

Q albumin was significantly higher in acute confusional state (ACS) than in non-ACS diffuse NPSLE (anxiety disorder, cognitive dysfunction, mood disorder and psychosis) or in focal NPSLE. Anti-Sm, but not anti-NR2, anti-P or anticardiolipin, was significantly elevated in ACS compared with the other 2 groups of NPSLE, although serum anti-NR2 was significantly higher in ACS than that in focal NPSLE. Multiple regression analysis confirmed the significant contribution of anti-Sm (p=0.0040), but not anti-NR2 (p=0.5023), anti-P (p=0.2651), or anti-cardiolipin (p=0.6769) in the elevation of Q albumin.

CONCLUSIONS

The data demonstrate that serum anti-Sm antibodies play a most important role in the disruption of BBB in NPSLE.

Evaluation of blood-brain barrier function by quotient alpha2 macroglobulin and its relationship with interleukin-6 and complement component 3 levels in neuropsychiatric systemic lupus erythematosus

Although quotient of alpha2 macroglobulin (Qα2MG) was previously reported to be useful for the evaluation of blood–brain barrier (BBB) function, it is not commonly used. We therefore evaluated BBB function among the various subsets of neuropsychiatric systemic lupus erythematosus (NPSLE) using quotient Q α2MG. Furthermore, we determined the correlation between Q α2MG and cerebrospinal (CSF) interleukin (IL)-6 level and quotient complement component 3 (Q C3). To determine intrathecal production of C3, the C3 index (Q C3/Q α2MG) was also calculated. Fifty-six patients with SLE were included in this study. Of these, 48 were diagnosed with NPSLE, consisting of 30 diffuse NPSLE patients (acute confusional state (ACS): n = 14, non-ACS: n = 16) and 18 patients with focal NPSLE. CSF IL-6 concentration, and paired serum and CSF levels of α2MG and C3, were measured by enzyme-linked immuno solvent assay (ELISA). The Q α2MG, Q C3, and C3 index were then calculated. Q α2MG, Q C3, and IL-6 concentrations in the CSF were significantly elevated in NPSLE compared with non-NPSLE. Among the subsets of NPSLE, significant increases in Q α2MG, CSF IL-6, and Q C3 were observed in ACS compared with non-ACS or focal NPSLE. There was a positive correlation between CSF IL-6 level and Q α2MG, as well as between Q C3 and Q α2MG, in diffuse NPSLE. There were no significant differences in C3 index between NPSLE and non-NPSLE, as well as among the subgroups of NPSLE. Our study suggests that BBB disruption is present in ACS, and elevated levels of IL-6 and C3 in CSF in diffuse NPSLE, especially in ACS, might result from their entry to the CSF from the systemic circulation through the damaged BBB, as well as increased intrathecal production. Furthermore, Q α2MG might be useful for the evaluation of BBB integrity.

Interferon-γ Is Associated with Cerebral Atrophy in Systemic Lupus Erythematosus

OBJECTIVE

We evaluated the cerebrospinal fluid (CSF) cytokine profile and magnetic resonance imaging (MRI) findings in systemic lupus erythematosus (SLE) patients with central nervous system (CNS) involvement.

METHODS

Consecutive SLE patients followed at the rheumatology unit were enrolled into this study. Neurologically asymptomatic controls were matched for age and sex and recruited during myelography. SLE patients were assessed for disease activity (Systemic Lupus Erythematosus Disease Activity Index; SLEDAI) and cumulative damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index; SDI). All subjects underwent MRI scans and blood and CSF withdrawal. Immunoglobulin G (IgG) and albumin were measured by nephelometry and link indexes were calculated according to the literature. Interleukin (IL)-12 p40/p70, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and IL-10 were measured by enzyme-linked immunosorbent assay.

RESULTS

We included 20 SLE patients (18 women, mean age 30.2 ± 9.2 years, range 19-45) with CNS manifestations. Increased IL-12 p40/p70, IFN-γ, TNF-α, and IL-10 CSF levels were observed in SLE patients. Mild pleocytosis was observed in 8 (66%) SLE patients and intrathecal production of IgG was observed in 2 (10%) SLE patients. Three (15%) SLE patients had demyelinating lesions, 5 (25%) patients had cerebral atrophy, and 12 (60%) patients had ischemic lesions on MRI. We observed that the cerebral lesion count was associated with CNS manifestations and SDI scores. We observed a significant cerebral volume reduction in SLE patients compared to controls (p < 0.001). Moreover, a direct correlation between cerebral volume reduction and CSF IFN-γ levels was observed (r = 0.5, p = 0.01).

CONCLUSIONS

IL-12 p40/p70, IFN-γ, TNF-α, and IL-10 CSF levels were increased in SLE patients with CNS manifestations, but only IFN-γ was associated with a cerebral volume reduction in SLE, suggesting an immunological basis for global atrophy in SLE.

Endothelium and the brain in CNS lupus

Central nervous system (CNS) involvement in systemic lupus erythematosus (SLE) is common and results in different clinical manifestations. Several pathogenic mechanisms have been suggested to play a rolein determiningsuch a varietyof clinicalsymptoms.The thrombophilicstateassociatedto the presence of antiphospholipidantibodies has been suggested to be responsible for a noninflammatory vasculopathywhichcauses clear ischaemiceventsas well as alterationsof the cerebralmicrocirculation that are likely associated to seizures, cognitive dysfunction or psychosis. Although less frequent, a true vasculitic process affecting cerebral circulation has also been reported. In both cases, brain endothelium does represent the target of the pathogenic mechanisms. Brain endothelial cells display peculiar functional and phenotypical characteristics in comparison with endothelial cells from other anatomical districts, raising the possibility that this might be the reason for its susceptibility in lupus disease. We review and present data suggesting that a higher and firmer expression of beta 2 glycoprotein I on endothelialcell membranes can be responsiblefor a selective damage/activation by circulating anti-beta 2 glycoprotein I, and that antiendothelial cell antibodies crossreact with brain endothelium and in some cases, specifically bind brain endothelial cells only in lupus patients with central nervous involvement.

Autoantibody profiling on human proteome microarray for biomarker discovery in cerebrospinal fluid and sera of neuropsychiatric lupus

Autoantibodies in cerebrospinal fluid (CSF) from patients with neuropsychiatric systemic lupus erythematosus (NPSLE) may be potential biomarkers for prediction, diagnosis, or prognosis of NPSLE. We used a human proteome microarray with~17,000 unique full-length human proteins to investigate autoantibodies associated with NPSLE. Twenty-nine CSF specimens from 12 NPSLE, 7 non-NPSLE, and 10 control (non-systemic lupus erythematosus)patients were screened for NPSLE-associated autoantibodies with proteome microarrays. A focused autoantigen microarray of candidate NPSLE autoantigens was applied to profile a larger cohort of CSF with patient-matched sera. We identified 137 autoantigens associated with NPSLE. Ingenuity Pathway Analysis revealed that these autoantigens were enriched for functions involved in neurological diseases (score = 43).Anti-proliferating cell nuclear antigen (PCNA) was found in the CSF of NPSLE and non-NPSLE patients. The positive rates of 4 autoantibodies in CSF specimens were significantly different between the SLE (i.e., NPSLE and non-NPSLE) and control groups: anti-ribosomal protein RPLP0, anti-RPLP1, anti-RPLP2, and anti-TROVE2 (also known as anti-Ro/SS-A). The positive rate for anti-SS-A associated with NPSLE was higher than that for non-NPSLE (31.11% cf. 10.71%; P = 0.045).Further analysis showed that anti-SS-A in CSF specimens was related to neuropsychiatric syndromes of the central nervous system in SLE (P = 0.009). Analysis with Spearman’s rank correlation coefficient indicated that the titers of anti-RPLP2 and anti-SS-A in paired CSF and serum specimens significantly correlated. Human proteome microarrays offer a powerful platform to discover novel autoantibodies in CSF samples. Anti-SS-A autoantibodies may be potential CSF markers for NPSLE.

Clinical analysis of cerebrospinal fluid interleukin-6 in neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To clarify the clinical usefulness of cerebrospinal fluid (CSF) interleukin-6 (IL-6) measurement in patients with neuropsychiatric systemic lupus erythematosus (NPSLE), we studied CSF IL-6 levels in patients with NPSLE and analyzed the association between CSF IL-6 levels and other clinical findings of NPSLE.

PATIENTS AND METHODS

We retrospectively analyzed records of 37 patients (33 females and four males) with NPSLE admitted to our hospital between January 2003 and December 2008.

RESULTS

All patients showed neuropsychiatric symptoms. Fourteen patients showed abnormalities in brain magnetic resonance imaging (MRI) and 12 patients had abnormal findings in electroencephalography (EEG). Increased CSF cell counts and elevated levels of CSF IL-6 were found in 11 and 30 patients, respectively. Elevated levels of CSF IL-6 were not statistically correlated with specific abnormalities in the blood analysis, in increased CSF cell counts, and in abnormalities in the brain MRI and EEG. In addition, a group of NPSLE patients positive for antiphospholipid antibodies (aPL) showed lower CSF IL-6 than the patients negative for aPL.

CONCLUSION

These results indicated that CSF IL-6 might be useful in diagnosis of NPSLE. However, general assessments of patients based on various factors (clinical manifestations, imaging findings and CSF examinations) are also required.

Neuropsychiatric lupus and association with cerebrospinal fluid immunoglobulins: a pilot study

BACKGROUND

Recent experimental evidence points to brain-reactive antibodies as a key factor in the pathogenesis of neuropsychiatric systemic lupus erythematosus (central nervous system-SLE). However, clinical studies in which circulating (serum) autoantibodies were correlated with neuropsychiatric manifestations have not produced consistent findings.

OBJECTIVES

To test the hypothesis that autoantibodies in cerebrospinal fluid are more reflective of functional brain damage.

METHODS

We compared the behavioral profiles of 12 NP-SLE patients, some of whom had immunoglobulin G in their CSF.

RESULTS

Western blotting revealed heavy and light chain IgG bands in six patients similar in age to the subgroup of CSF IgG-free patients. A series of serological measures did not differ between the subgroups, but SLEDAI scores and daily steroid doses were higher in patients with IgG in their CSF. All three patients with severe deficits in verbal and executive functions were positive for the CSF IgG, while three other patients with psychosis were CSF IgG-negative.

CONCLUSIONS

Although the present sample size is relatively small, the results support the relationship between disease severity and central manifestations of autoimmunity. They also emphasize the importance of clinical studies that compare subpopulations of NP-SLE patients and justify development of animal models in which controlled immune mechanisms induce specific deficits in behavior.

Serum and cerebrospinal fluid autoantibodies in patients with neuropsychiatric lupus erythematosus. Implications for diagnosis and pathogenesis

Background

Despite the uncertainty in the diagnosis of neuropsychiatric involvement in systemic lupus erythematosus (SLE), attempts have been made to record the association of certain antibodies in serum with neuropsychiatric (NP) manifestations. We aimed to assess the behaviour and the association of serum and cerebrospinal fluid (CSF) autoantibodies with NP manifestations in SLE patients (NPSLE).

Methodology/Principal Findings

Forty-seven SLE patients, hospitalized because of NP manifestations were included. They were evaluated at hospitalization and six months later, and serum and CSF samples were obtained at each evaluation. As controls, serum samples were taken from 49 non-NPSLE patients at hospitalization and six months later; serum and CSF samples were also obtained from 6 SLE patients with septic meningitis, 16 surgical SLE patients and 25 patients without autoimmune diseases. Antinuclear, anti-dsDNA, anti-ribosomal P, Anti-N-Methyl-D-Aspartate receptor (NMDAR), anti-cardiolipin, and anti-β2 glycoprotein-I antibodies were measured. In serum, anti-ribosomal P, anti-NMDAR, and other antibodies did not differentiate among SLE groups, and the levels of all antibodies were similar among the SLE groups. Six-months later, this scenario remained unchanged and the decrease in the levels of some autoantibodies reflected a decline in disease activity, rather than a change in NPSLE. In CSF, only the presence and the levels of anti-NMDAR antibodies showed a characteristic distribution in central NPSLE and septic meningitis patients. Six months later the prevalence of most antibodies in CSF did not change, however the levels of anti-dsDNA, anti-ribosomal P, and anti-NMDAR decreased.

Conclusion

In NPSLE, autoantibodies in serum do not reflect their behaviour in CSF. All autoantibodies were elevated in septic meningitis reflecting the global penetration of serum antibodies into the CSF in this condition. Anti-NMDAR antibodies in CSF identified patients with central NPSLE; their continued presence in CSF 6 months after neurologic symptoms raise questions regarding the conditions under which they are pathogenic.

Interleukin-6 and chemokines in the neuropsychiatric manifestations of systemic lupus erythematosus

OBJECTIVE

To define the cytokine and chemokine profile in cerebrospinal fluid (CSF) from patients with neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Forty-two SLE patients who had been hospitalized because of NP manifestations were studied. Patients were evaluated at hospitalization and 6 months later; a CSF sample was obtained at each evaluation. As controls, CSF from 6 SLE patients with septic meningitis, 16 SLE patients with no history of NP manifestations (non-NPSLE), and 25 patients with nonautoimmune diseases were also studied. Soluble molecules, including cytokines (interleukin-2 [IL-2], IL-4, IL-6, IL-10, tumor necrosis factor alpha [TNFalpha], and interferon-gamma [IFNgamma]) and chemokines (monocyte chemotactic protein 1 [MCP-1], RANTES, IL-8, monokine induced by IFNgamma [MIG], and interferon-gamma-inducible 10-kd protein [IP-10]), were measured with the use of cytometric bead array kits.

RESULTS

CSF levels of the following molecules were significantly increased in NPSLE patients as compared with non-NPSLE and nonautoimmune diseases control patients, respectively: IL-6 (32.7 versus 3.0 and 2.96 pg/ml), IL-8 (102.8 versus 29.97 and 19.7 pg/ml), IP-10 (888.2 versus 329.7 [P not significant] and 133.6 pg/ml), RANTES (3.8 versus 2.5 and 2.2 pg/ml), MCP-1 (401.7 versus 257.9 [P not significant] and 136.9 pg/ml), and MIG (35.4 versus 11.4 and 3.5 pg/ml). Low levels of IL-2, IL-4, IL-10, TNFalpha, and IFNgamma were found in all groups. All cytokines and chemokines, except TNFalpha, were significantly higher among the SLE patients with septic meningitis than among the NPSLE patients. Six months later and in the absence of NP manifestations, all elevated molecule levels, except RANTES, in patients with NPSLE had decreased significantly, and no differences were noted between the NPSLE and non-NPSLE groups.

CONCLUSION

A central nervous system response composed of IL-6 and chemokines, but not Th1/Th2 cytokines, is associated with NP manifestations in SLE patients.

Anti-triosephosphate isomerase antibodies in cerebrospinal fluid are associated with neuropsychiatric lupus

We detected anti-triosephosphate isomerase antibodies (anti-TPI) in cerebrospinal fluid (CSF) in 5 of 12 neuropsychiatric lupus patients (41.6%) by Western blotting. C3d index was significantly higher in anti-TPI-positive patient (n=5, median 0.446) than in anti-TPI-negative patient (n=7, median 0.098) (p=0.019) CSF samples. TPI was detected from immune complexes (IC) isolated from CSF in 2 of 2 anti-TPI-positive patients tested and was not detected from IC in 5 of 5 anti-TPI-negative patients tested. Our results suggest that anti-TPI form IC in CSF and contribute to the pathogenesis of neuropsychiatric lupus by activating the complement system.

[Clinical significance of neuro-reactive autoantibodies in neuro-psychiatric systemic lupus erythematosus]

OBJECTIVE

To investigate the clinical significance of specific/non-specific neuro-reactive autoantibodies in the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE).

METHODS

Samples of serum and cerebrospinal fluid (CSF) were collected from 25 NPSLE patients, 11 patients with SLE complicated with central nervous system (CNS) infection (control group 1), and 10 SLE patients without CNS infection (non-NPSLE, control group 2)) were detected, Indirect immunofluorescence technique was used to detect the anti-nuclear antibody (ANA) based on the slides with human epithelium cell of laryngocarcinoma of the line Hep-2 or on the slides with cerebellum and peripheral nerve of monkey, he type of immunofluorescence were assayed.

RESULTS

The percentages of ANA positive serum of the NPSLE, SLE control 1, and SLE control 2 groups were 92% (23/25), 100% (11/11), and 100% (10/10) respectively without significant differences between any 2 groups (all P > 0.05). The percentage of ANA positive CSF of the NPSLE was 60% (15/25), significantly higher than that of the SLE control group 1 (27%, 3/11, P < 0.01). There was no significant correlation between the titer of serum ANA and the titer of CSF ANA (P > 0.05). The positive rate of neuro-reactive autoantibodies was 40% (10/25), significantly higher than those of the 2 control groups (both 0, both P > 0.001).

CONCLUSION

(1) The ANA positivity in the CSF of the NPSLE group is associated with the disease activity and CNS involvement, the higher the titer of autoantibodies the severe the clinical manifestations. (2) The neuro-reactive autoantibodies in the serum may associate with NPSLE with still unknown mechanism.

Elevated levels of soluble fractalkine in active systemic lupus erythematosus: potential involvement in neuropsychiatric manifestations

OBJECTIVE

To determine levels of the soluble form of the chemokine fractalkine (sFkn) and its receptor, CX(3)CR1, in patients with systemic lupus erythematosus (SLE) with neuropsychiatric involvement (NPSLE) and in SLE patients without neuropsychiatric involvement, and to assess their relationship with disease activity and organ damage.

METHODS

Levels of sFkn in serum and cerebrospinal fluid (CSF) were measured by enzyme-linked immunosorbent assay. Expression of Fkn and CX(3)CR1 was quantified using real-time polymerase chain reaction. Surface expression of CX(3)CR1 on peripheral blood mononuclear cells (PBMCs) was determined by flow cytometry. Disease activity and organ damage were assessed using the SLE Disease Activity Index (SLEDAI) and the Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index, respectively.

RESULTS

Serum sFkn levels were significantly higher in patients with SLE than in patients with rheumatoid arthritis (RA) or healthy controls. In addition, significant correlations between serum sFkn levels and the SLEDAI, the SLICC/ACR Damage Index, anti-double-stranded DNA and anti-Sm antibody titers, immune complex levels (C1q), and serum complement levels (CH50) were observed. Expression of CX(3)CR1 was significantly greater in PBMCs from patients with active SLE than in those from RA patients or healthy controls. Levels of sFkn were also significantly higher in CSF from untreated patients with newly diagnosed NPSLE than in SLE patients without neuropsychiatric involvement; treatment reduced both serum and CSF levels of sFkn in patients with SLE.

CONCLUSION

Soluble Fkn and CX(3)CR1 may play key roles in the pathogenesis of SLE, including the neuropsychiatric involvement. Soluble Fkn is also a serologic marker of disease activity and organ damage in patients with SLE, and its measurement in CSF may be useful for the diagnosis of NPSLE and followup of patients with NPSLE.

[Characteristic manifestations of neuropsychiatric systemic lupus erythematosus]

OBJECTIVE

To investigate the characteristic manifestations of neuropsychiatric systemic lupus erythematosus (NPSLE) in clinical practice.

METHODS

A total of 198 NPSLE cases from 1998 to 2003 in Peking Union Medical College Hospital, were included. Their clinical manifestations and the results of accessory examination such as serology, lumbar puncture, head magnetic resonance imaging, and electroencephalogram were analyzed.

RESULTS

The most frequent manifestations of the NPSLE included: headache, psychiatric disorder, seizure, stroke, and acute confusional state. Fifty-two patients took head magnic resonance imaging, and 34 of them showed abnormal, including stroke attack. Among 48 patients who only had a complaint of headache, the increase of intracranial pressure and cerebral spinal fluid protein was significantly higher than other NPSLE syndromes (P < 0.05).

CONCLUSION

Diagnosis of NPSLE was mainly based on its clinical manifestations. Head magnetic resonance imaging and cerebral spinal fluid examination may be helpful. More specific accessory examinations require further development.

Antiribosomal P protein antibodies in cerebrospinal fluid are associated with neuropsychiatric systemic lupus erythematosus

OBJECTIVE

To investigate whether antiribosomal P protein antibodies (anti-P) are present in the cerebrospinal fluid (CSF) of patients with systemic lupus erythematosus (SLE), and if presence of anti-P in CSF is more strongly related to the appearance of neuropsychiatric SLE (NPSLE) than anti-P in serum.

METHODS

CSF and serum samples from 70 patients with SLE were used. Patients were divided into 4 groups: 21 patients with neurologic syndromes of the central nervous system (CNS); 19 patients with diffuse psychiatric/neuropsychological syndromes; 10 patients with complex presentations (neurologic syndromes of the CNS plus diffuse psychiatric/neuropsychological syndromes); and 20 patients without NPSLE based on diagnostic criteria for 19 NPSLE syndromes proposed by the American College of Rheumatology. IgG anti-P in CSF and serum samples were detected by Western blotting using rat liver ribosomes. Inhibition assay was performed using 5 anti-P-positive CSF samples preincubated with synthetic ribosomal P peptide. Western blotting results were compared with those from ELISA with synthetic ribosomal P peptide as antigen. The association of CSF and serum anti-P with NPSLE was analyzed.

RESULTS

CSF and serum IgG anti-P by Western blotting were detected, respectively, in 20 (28.6%) and 32 (45.7%) of 70 patients. The presence of IgG anti-P by Western blotting in the CSF was supported by positive results in the inhibition assay and significant association with CSF IgG anti-P titers by ELISA. The frequency of CSF anti-P by Western blotting in SLE patients with serum anti-P was significantly higher than in SLE patients without serum anti-P (18/32 vs 2/38; p < 0.001). The frequency of CSF anti-P by Western blotting in patients with NPSLE was significantly higher than in patients without NPSLE (19/50 vs 1/20; p < 0.01). The frequency of CSF anti-P by Western blotting in the group with complex presentations (10/10) was significantly higher than in the other 3 groups [neurologic syndromes of CNS (5/21); diffuse psychiatric/neuropsychological syndromes (4/19); and patients without NPSLE (1/20)] (p < 0.001). The frequency of serum anti-P by Western blotting in patients with NPSLE was not significantly higher than in patients without NPSLE (25/50 vs 7/20; p = 0.192).

CONCLUSION

These results suggest that the presence of IgG anti-P in CSF of SLE patients may be involved in the appearance of NPSLE, especially in complex presentations. Measurement of IgG anti-P in CSF by Western blotting may be more useful for diagnosis of NPSLE than measurements in serum.

[Differential diagnosis of chronic inflammatory diseases of the central nervous system. Cerebrospinal fluid diagnosis and immunological parameters]

A number of neurological syndromes may be evoked by involvement of the nervous system due to systemic diseases such as lupus erythematosus, sarcoidosis, Behcet's disease, and Sjogren's syndrome. Because of different treatment strategies, it is important to distinguish between these different diseases. Neither clinical signs nor additional analyses such as serological findings or cerebrospinal fluid analysis are able to differentiate between the diseases with certainty. Nevertheless, diagnosis may finally be made taking all findings together. Here we compare typical clinical and cerebrospinal fluid findings in neurosarcoidosis, neurolupus, neuro-Behcet, and nervous system involving Sjogren's syndrome, with special emphasis on those findings allowing differentiation of the respective diseases.

The heterogeneity of neuropsychiatric systemic lupus erythematosus is reflected in lack of association with cerebrospinal fluid cytokine profiles

The objective was to study the occurrence of autoantibodies and cytokines in serum and cerebrospinal fluid (CSF) in neuropsychiatric systemic lupus erythematosus (NPSLE). In total, 28 consecutive patients with NPSLE and 16 systemic lupus erythematosus (SLE) patients without neuropsychiatric involvement (non-NPSLE) were studied. IFN-alpha, IL-6, IL-10, soluble terminal complement complex (TCC), anti-ribosomal P protein antibodies (anti-P) and anti-cardiolipin antibodies (aCL) were measured in serum and CSF by immunoassays. Analyses of white blood cell differential count, CSF-albumin/serum-albumin ratio, IgG-index in CSF and isoelectric focusing in serum and CSF were also performed. CSF specimens from 23 healthy individuals were used as controls. IFN-alpha was elevated in the CSF of 5 of 28 NPSLE patients compared to three of 14 among the non-NPSLE patients. IL-6 was elevated in CSF in three of 26 NPSLE patients. Normal concentration of IL-10 was found in CSF in all 27 NPSLE-patients analysed. IFN-alpha in serum was elevated in 18 of 28 NPSLE patients. No distinct clinical phenotype was related to elevated cytokine concentration in serum or CSF. One patient with cerebral involvement complicated by progressive multifocal leukoencephalopathy displayed a very high IFN-alpha concentration in serum. High concentration of TCC was present in CSF from only one patient with systemic vasculitis and focal cerebral symptoms. In conclusion, the results of this study suggest that the diagnostic value of serum and CSF concentrations of IFN-alpha, IL-10, IL-6 and TCC is limited in unselected neuropsychiatric SLE, probably due to the heterogeneity of NPSLE pathogenesis.

Ribosomal P antibodies and CNS lupus

Within two years of the recognition of autoantibodies to ribosomal P proteins in patients with systemic lupus erythematosus (SLE) an association with anti-P autoantibodies with psychosis was noted. While there has been some controversy about this association, ample evidence suggests a meaningful relationship between anti-P antibodies and central nervous system (CNS) disease. This evidence consists of 1) seven independent studies showing a strong relationship between anti-P antibodies and CNS disease; 2) longitudinal studies showing fluctuations of anti-P antibodies with episodes of psychosis; 3) correlation of anti-P antibodies with general disease activity; and 4) acid eluates form lupus renal tissue were found to contain anti-P antibodies enriched 30-fold with respect to their specific activity in serum heralding a direct role of anti-P antibodies in disease expression. Finally, there is evidence that the P protein resides on normal cells in an immunologically accessible way and evidence exists that anti-P antibodies are able to bind and penerate cells in culture, and once inside cells can affect a profound inhibition of protein synthesis in living cells. Taken together, these observations provide evidence linking anti-P antibodies to various forms of CNS disease. While this is true, there are other autoantibodies in SLE patients such as anti-dsDNA and antiglial fibrillary protein which may also play a role in the CNS disease of SLE patients. Continued study will inform us of the relative contribution of these autoantibodies to CNS disease in SLE patients.

Neuronal and astrocytic damage in systemic lupus erythematosus patients with central nervous system involvement

OBJECTIVE

Symptoms originating from the central nervous system (CNS) frequently occur in patients with systemic lupus erythematosus (SLE). CNS involvement in lupus is associated with increased morbidity and mortality. Currently, reliable markers for activity in this condition are absent. The goal of this study was to determine the level of the light subunit of the neurofilament triplet protein (NFL) and that of glial fibrillary acidic protein (GFAP) in the cerebrospinal fluid of SLE patients with clinically verified CNS involvement and compare them with the levels in SLE patients without CNS involvement.

METHODS

We assessed cerebrospinal fluid obtained from 99 patients with SLE and 99 age-matched controls for the presence of soluble molecules indicating neuronal destruction and astrogliosis-NFL and GFAP, respectively. Patients were evaluated clinically, with magnetic resonance imaging (MRI) of the brain, cerebrospinal fluid analyses, and neuropsychiatric tests.

RESULTS

In the group of lupus patients with CNS involvement, intrathecal levels of NFL and GFAP were increased an average of 7-fold (P </= 0.0001) and 3-fold (P </= 0.05), respectively, compared with the levels in SLE patients without overt CNS disease. Intrathecal levels of NFL correlated significantly with cerebrospinal fluid levels of interleukin-6 (IL-6) (P </= 0.005), IL-8 (P </= 0.005), pleocytosis (P </= 0.05), the albumin ratio (P </= 0.0005), and the presence of oligoclonal IgG bands (P </= 0.005). Cerebrospinal fluid levels of both NFL and GFAP also showed a significant correlation with MRI abnormalities (P </= 0.001). Successful cyclophosphamide treatment of CNS lupus resulted in significantly decreased levels of both proteins; levels of GFAP reached those observed in healthy subjects.

CONCLUSION

This study is the first to show biochemical signs of neuronal and astrocytic damage in patients with neuropsychiatric lupus. It is suggested that biochemical markers of brain damage should be used as a followup tool in this patient group.

Kinins and cytokines in plasma and cerebrospinal fluid of patients with neuropsychiatric lupus

OBJECTIVE

To evaluate the kinin system components and selected cytokines in plasma and cerebrospinal fluid (CSF) of patients with neuropsychiatric lupus (NPL).

METHODS

We studied 29 women with active NPL and 29 healthy women matched to patients for age. Low (LKg) and high molecular weight kininogen (HKg) and cytokine concentrations [interleukin 1beta (IL-1beta), IL-6, IL-8, IL-10, and tumor necrosis factor-a (TNF-a)] were determined by ELISA. The activities of tissue kallikrein, plasma prekallikrein, and kininase II were assayed by their action on selective substrates.

RESULTS

Compared to controls, patients with NPL presented increased plasma and CSF levels of LKg, HKg, and prekallikrein, increased activity of tissue kallikrein and kininase II, and increased levels of IL-6, IL-10, and TNF-a (p < 0.001 each comparison). IL-1beta levels were increased in patient plasma (p < 0.001), whereas plasma IL-8 levels did not differ from controls. IL-1beta and IL-8 were not detected in CSF of patients or controls.

CONCLUSION

The increased levels of kininogen fractions, kallikreins, and kininase II in patient plasma and CSF indicate overactivity of the kinin system, suggesting intense kinin production. Since kinins may induce the production of proinflammatory cytokines including IL-1beta, IL-6, and TNF-a, these findings support the participation of kinins and cytokines in the acute manifestations of NPL. Most of the variables evaluated in patients' CSF increased proportionally in relation to plasma levels. In contrast, the activity of tissue kallikrein in patient CSF increased out of proportion to plasma levels, appearing to be locally synthesized in response to brain involvement.

Increased levels of proinflammatory cytokines and nitric oxide metabolites in neuropsychiatric lupus erythematosus

OBJECTIVE

To investigate systemic and intrathecal production of proinflammatory cytokines in relation to cerebrospinal fluid (CSF) nitric oxide (NO) release in patients with neuropsychiatric lupus erythematosus (NPLE).

METHODS

Thirty patients with NPLE rated as mild, moderate, or severe were studied and CSF was obtained from 21 of these. Cytokine mRNA expressing cells were detected by in situ hybridisation. Soluble cytokines were assessed by enzyme linked immunosorbent assay (ELISA). Nitrite and nitrate were determined by capillary electrophoresis.

RESULTS

Patients with NPLE had high numbers of lymphocytes expressing mRNA for tumour necrosis factor alpha (TNFalpha), interferon gamma, and interleukin 10 in blood. The number of peripheral blood TNFalpha mRNA positive cells correlated strongly with the level of NO metabolites in the CSF (r(2)=0.69). Both the number of peripheral blood mononuclear cells expressing mRNA for TNFalpha as well as the CSF level of NO metabolites correlated with NPLE disease severity.

CONCLUSION

These data suggest that increased peripheral production of proinflammatory cytokines such as TNFalpha may contribute both to an increased production of NO in the central nervous system and to generation of clinical NPLE. The data also support the possibility that measurements of NO metabolites in CSF may be of value in the diagnosis of neurological symptoms related to SLE.

Intrathecal cytokines in systemic lupus erythematosus with central nervous system involvement

Symptoms originating from central nervous system (CNS) are frequently occuring in patients with systemic lupus erythematosus (SLE). Reliable diagnostic markers for this condition are presently lacking. Importantly, CNS involvement in lupus patients is associated with increased morbidity and mortality. The aim of this retrospective evaluate was to study the diagnostic value of cerebrospinal fluid (CSF) cytokine levels in SLE patients with CNS involvement. 34 patients with SLE were hospitalized and investigated for the presence of CNS lupus. These patients were evaluated clinically and with magnetic resonance imaging (MRI) and CSF analyses, as well as with neuropsychiatric tests. 13 patients were found to have CNS lupus whereas another four of the patients fulfilled the criteria for CNS involvement but were excluded from this group due to other causes of CNS involvement. Lastly, in 17 SLE cases, the diagnosis of CNS lupus could not be confirmed. CSF levels of interleukin-6 (IL-6) and IL-8, as well as the CSF/serum IL-6 ratio, were elevated in the CNS lupus group, compared with the 17 SLE patients not fullfilling a diagnosis of cerebral lupus. Interestingly, follow-up of five patients being successfully treated for CNS lupus revealed profound decrease of intrathecal IL-6 levels. These results indicate that analysis of CSF cytokine levels, especially IL-6 and IL-8, may be useful in the diagnostics and possibly follow-up of SLE patients with cerebral lupus.

Evaluation of cerebrospinal anticardiolipin antibodies in lupus patients with neuropsychiatric manifestations

To evaluate the role of cerebrospinal fluid (CSF) anticardiolipin antibody (aCL) in lupus patients with neuropsychiatric manifestations, paired measurements of aCL, in the serum and CSF, were performed using the ELISA method in lupus patients (n=31) and controls with other medical diseases (n=8). High titers of CSF IgG-aCL were detected in cerebral lupus patients with lupus headache, acute psychosis, cognitive impairment, high cortical dysfunction, and altered consciousness. Intrathecal synthesis, rather than the diffusion of IgG-aCL from serum to compartment of the central nervous system, occurred in these NPLE patients. The binding of aCL to brain components might play a role in the development of neuropsychiatric manifestations in cerebral lupus patients.

Soluble L-selectin levels in serum and cerebrospinal fluid in patients with multiple sclerosis and systemic lupus erythematosus

Soluble L-selectin (sL-selectin) concentrations were measured in paired samples of serum and cerebrospinal fluid by an ELISA method. Patients with several forms of multiple sclerosis (MS) and systemic lupus erythematosus with central nervous system involvement (SLE-CNS) were investigated. Elevated CSF sL-selectin concentrations were found in patients with SLE-CNS (7.62 +/- 3.31 ng/ml) and with relapsing-remitting form of MS (6.99 +/- 4.72 ng/ml) compared to the control group (4.00 +/- 0.95 ng/ml). The data presented suggest some similarities between inflammatory/immunological events in the central nervous system in patients with SLE-CNS and relapsing-remitting form of MS. Immunological heterogeneity in MS is suspected.