JPH10274655A - Systemic lupus erythematosus pathological diagnosis agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an effective systemic lupus erythematosus pathological diagnosis agent. SOLUTION: A diagnosis agent contains a synthetic liposome P peptide- albumin binding binder where the synthetic liposome P peptide containing C- terminus, 22 amino acids with a purity of 99% is connected to albumin. Especially, the weight composition ratio of the synthetic liposome P peptide and the albumin should preferably be 10 to 100-300 to 500.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a diagnostic agent for systemic lupus erythematosus, and more particularly, to an enzyme-linked immunosorbent assay (EL).
The present invention relates to a diagnostic agent for central nervous system pathology of systemic lupus erythematosus for measuring serum anti-ribosomal P protein antibody (anti-P antibody) levels by ISA method).

[0002]

2. Description of the Related Art Systemic lupus erythematosus (SLE)
A major feature of autoimmune diseases involving multiple organs is the appearance of various types of autoantibodies. Central nervous system (CNS) disorders
It is a relatively common complication of E and is an abnormal mental function such as brain syndrome or non-organic psychosis (neurosis, depression, schizophrenia, etc.) (so-called CNS lupus)
Is one feature of the CNS disorder in SLE. The frequency is said to range from 25 to 60% of all patients including those with mild illness. However, C in SLE
The mechanism of NS disorders is not well understood, and a major factor that has made it difficult to treat this disease in the past is that its diagnosis and evaluation of disease activity were difficult.

An autoantibody against ribosomal P protein (anti-P
Antibody) is found in 12-16% of SLE patients. Anti-P
Antibodies have been reported to have very high specificity for lupus psychosis (eg, Bonfa E, et al "Associ
ation between lupus psychosis and anti-ribosomal P
protein antibodies. "N Eng J Med 317: 265-271,1987
Some reports have shown discrepancies in the relationship between this antibody and SLE neuropathy (eg, Derkse
n RHWM, et al "A prospective study on antiribosoma
l P protein in two cases of familial lupus and rec
urrent psychosis. "Ann Rheum Dis 49: 779-782, 1990
, Etc.), the significance of this antibody in SLE was mixed in the report.

[0004] Under these circumstances, the differences among the reporters are the differences in measurement methods, diagnostic criteria for lupus psychosis, and research progress,
Others have reported that racial differences do not affect the sensitivity of the assay (Teh LS, Isenb
erg DA "Antiribosomal P protein antibodies in syst
emic lupus erythematosus. "A reappraisal. Arthriti
s Rheum 37: 307-315, 1994). However, the report does not mention the specificity of the assay, which has a significant effect on the results.

[0005] Anti-P antibodies are phosphorylated proteins of P0, P1, and P2 present in the 60S subunit of the ribosome of eukaryotic cells (the molecular weights are 38 kd, 19 kd, and 17 kd, respectively).
d), and these ribosomal P proteins are
Has a common antigenic determinant consisting of amino acids (Elko
n KB, et al "Identification and chemical synthesis
of a ribosomal protein antigenic determinant in sy
stemic lupus erythematosus. "Proc Natl Acad Sci US
A 83: 7419-7423, 1986). However, even in a measurement system using a method using recombinant ribosome P protein as an antigen, a result different from the conventional method has been reported (Yoshio).
T, et al "Quantitation of antiribosomal P0 protei
n antibodies by ELISA with recombinant P0 fusion p
rotein andtheir association with central nervous s
ystem disease in systemic lupuserythematosus. "JR
heumatol 22: 1681-1687, 1995).

[0006]

As described above, although it has been reported that an anti-P antibody has a very high specificity for lupus psychiatric disorders, depending on the report, this antibody may be used in combination with SL.
There is disagreement about the relationship of E to clinical symptoms.

An object of the present invention is to re-evaluate the relationship between an anti-P antibody and lupus psychosis and to provide an effective diagnostic agent for systemic lupus erythematosus.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to provide a synthetic ribosome P peptide-albumin conjugate in which a synthetic ribosome P peptide containing C-terminal 22 amino acids having a purity of 99% or more is bound to albumin. It has been found that the problem can be solved by a diagnostic agent for systemic lupus erythematosus characterized by the following.

In the present invention, a synthetic ribosome P peptide having a high purity containing 22 amino acids at the C-terminus is bound to albumin, and this is used as an antigen for enzyme-linked immunosorbent assay (ELIS).
By measuring the anti-P antibody titer in the serum obtained from the subject according to A), the pathological diagnosis of lupus psychosis (including both brain syndrome and non-organic psychosis) can be accurately performed. .

Most conventional studies use a synthetic peptide consisting of 22 amino acids as an antigen in the measurement of anti-P antibody in SLE patient serum. However, the purity of the synthetic peptide varies from study to study, and the carrier protein binding the peptide is not constant. Further, in a measurement system using the method using recombinant T. ribosome P protein as an antigen, it is possible that a product derived from bacteria is contaminated in the antigen.

[0011] Accordingly, the present inventors assumed that the differences in the antigens used in such a measurement system are likely to have produced different conclusions on the correlation between anti-P antibodies and lupus psychiatric disorders, and In the present invention, an ELISA method having high specificity for an anti-P antibody using a synthetic ribosome P peptide consisting of 22 amino acids having a purity of 99% or more was developed.

Using this method, the relationship between lupus psychiatric disease and serum anti-P antibody was re-examined. SLE other than mental illness
It was shown that a significant increase was observed as compared with the patients, and the correlation between the two was supported. It is concluded that the discrepancy in previous reports on the correlation between anti-P antibodies and lupus psychosis was likely due to differences in the purity of ribosomal P-peptide.

In fact, from the past reports, there is a difference that cannot be overlooked in the purity of the synthetic ribosomal P peptide used in the measurement system. For example, Bonfa and Schneebaum et al., Who reported a significant correlation between serum anti-P antibodies and lupus psychosis, et al.
Other inventors who reported that purified ribosomal P-peptide having a high purity of 5 to 99% were used, but reported that there was no significant correlation between the two, used a ribosomal P-peptide of only 50% pure. And does not report any such purity.

[0014] Examples of the albumin binding partner of the ribosome P peptide include human serum albumin, bovine serum albumin, and ovalbumin. Here, since ovalbumin and bovine serum albumin are heterologous proteins, even a normal person may have an antibody against them, and this may cause a non-specific reaction when measuring anti-ribosomal P antibody. Cause it to occur. On the other hand, since human serum albumin (HSA) is originally a human homologous protein, such a non-specific reaction is unlikely to occur, so that it is excellent in measuring anti-ribosome P antibody,
It is particularly effective for the diagnostic agent of the present invention.

In the present invention, no abnormal increase in anti-P antibody was observed in the cerebrospinal fluid of lupus psychiatric patients, and it was considered that the possibility that this antibody was produced in the central nervous system was low. .

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The synthetic ribosome P peptide containing 22 amino acids at the C-terminal used in the present invention can be easily synthesized using a commercially available peptide synthesizer.
As a method for purifying the obtained peptide to a purity of 99% or more, various conventionally known methods can be used, and examples thereof include high performance liquid chromatography, affinity chromatography, and electrophoresis.

The purified synthetic ribosome P-peptide is preferably made into a solution having a concentration of 0.1 to 100 mg / ml, more preferably 5 to 10 mg / ml. Examples of the solvent include a 0.05 to 0.25 M phosphate buffer (PBS), and the pH is preferably 5.0 to 8.0, particularly preferably 7.0 to 7.4.

On the other hand, commercially available human serum albumin (HSA) and bovine serum albumin (BSA ovalbumin (OVA)) can be used, and conventionally known methods (eg, cellulose acetate electrophoresis, Sephadex) It is preferable to purify the purified albumin in the same solvent as above in a concentration of 1 to 1000 mg / ml, more preferably 10 to 1000 mg / ml.
It is preferred to dissolve at a concentration of 100 mg / ml.

The binding between the synthetic ribosome P peptide and albumin is determined by the method of Avrameas S "Coupling of enzymes to protein".
ins with glutaraldehyde: use of the conjugates for
thedetection of antigens and antibodies "Immunoch
emistry 6: 43-52, 1969, based on the glutaraldehyde method. Specifically, a glutaraldehyde solution is added to a mixture of the above synthetic ribosome P peptide solution and albumin solution, and the mixture is allowed to stand. Then, the mixture is centrifuged, and the supernatant is dialyzed. An albumin conjugate can be obtained. Alternatively, Fujiwara Ket
al, "Novel preparation method of immunogen for hyd
rophobic hapten, enzyme immunoassay for daunomycin
and adriamycin "J Immunol Method 45: 195-2-3, 198
As described in 1, an equivalent conjugate can be obtained by a method using γ-maleimide n-butyric acid N-hydroxysuccinimide ester (GMBS).

Further, in the present invention, the weight composition ratio of the synthetic ribosome P peptide and albumin is 10 to 300 to 10
It is preferably from 0 to 500, especially from 40 to 60 to 200 to 400. Within this range, particularly effective measurement results correlated with the pathology of the central nervous system of systemic lupus erythematosus can be obtained.

Further, the synthetic ribosome P peptide-albumin conjugate of the present invention is preferably a solution having a concentration of preferably 0.6 mg / ml or more, more preferably 1 to 10 mg / ml, more preferably Is stored at -20 ° C. or lower, more preferably at -20 ° C. to −70 ° C., so that the same stability when used in a measurement system by ELISA to be applied in the present invention even after aging for one year or more The obtained measurement result can be obtained.

In the present invention, the known enzyme antibody method (EL
ISA), ie, synthetic ribosome P-peptide-
The albumin-conjugated substance is bound to a solid phase (usually a plastic plate) as an antigen, reacted with the serum of the subject, then reacted with peroxidase-labeled anti-human IgG, and then o-phenylenediamine, H ₂ O The anti-P antibody value in serum can be measured by developing a color with a substrate solution containing ₂ , measuring OD492, and measuring the enzyme activity of the well in the plate. Also, instead of peroxidase-labeled anti-human IgG, alkaline phosphatase-labeled anti-human IgG, biotin-labeled anti-human IgG
The measurement can be performed in the same manner by using such a method.

According to the present invention, it has been found that such anti-P antibody correlates with lupus psychosis of systemic lupus erythematosus, and that the synthetic ribosome P peptide-albumin conjugate functions as an effective diagnostic agent for systemic lupus erythematosus. Was confirmed.

[0024]

The present invention will be illustrated below by way of examples, but the present invention is not limited to these examples.

1) Patients In the present invention, 75 SLE patients were used. All of these patients were from the American College of Rheumatology 1982 SLE.
It met the revised criteria for the classification of (14). As shown in Table 1, of the 75 SLE patients, 26 lacked central nervous system symptoms, and 28 had lupus psychiatric illness (Shinnan power.
9 cases of cerebral organ syndrome characterized by impairment of cognition, memory and other intellectual functions, 19 cases of non-organic psychosis such as neurosis, mania, depression, schizophrenia), and 21 cases other than mental illness He exhibited central nervous system symptoms (non-psychotic CNS). Diagnosis of lupus and nonpsychotic CNS is based on the CSF Ig Index
Either (15, 16) and / or CSF IL-6 activity (17) were confirmed to be elevated.

[0026]

[Table 1]

2) Specimens Serum was collected from 75 SLE patients during their active period. Furthermore, for 21 patients, CSF (cerebrospinal fluid) was collected by lumbar puncture on the day of serum collection. These samples were stored at −20 ° C. until the measurement of the anti-P antibody. The measurement of anti-P antibody was performed by a person who had no prior knowledge of the diagnosis and clinical symptoms.

3) Synthesis of Ribosomal P Peptide The 22 amino acid sequence (Ar
Peptides corresponding to Temia Salina P2 protein (residues 90 to 111) were synthesized by a solid phase method using an automatic peptide synthesizer (PerkinElmer, Chiba). This peptide was purified by high performance liquid chromatography. The purity has been confirmed to be 99% or more by high performance liquid chromatography / amino acid analysis / microsequence method. The purified ribosome P peptide was used at a concentration of 5 mg / ml in a phosphate buffer (PBS, pH 7.2, 0.1
5M).

4) Preparation of Conjugate of Serum Albumin Human serum albumin (HSA; Miles, Elkhart, IN), bovine serum albumin (BSA; Miles), or ovalbumin (OVA; Miles) (300 mg / ml each) ) To 0.1 ml, add 0.9 ml of the above synthetic ribosome P peptide (5 mg / ml). To this is added 0.2 ml of glutaraldehyde (diluted to 1% with PBS) and left for 2 hours with gentle shaking. The product is centrifuged at 2 × 10 ⁴ rpm for 20 minutes. This supernatant was put into a dialysis membrane, and 0.15 M PBS was added.
Dialyze with. This was added at a concentration of 600 μg / ml or more to -20.
Store frozen at ℃.

5) Measurement of anti-P antibody Each well of a 96-well microtiter plate (made of vinyl chloride) was diluted with a ribosome P-HSA compound diluted to 15 μg / ml in a phosphate buffer (pH 7.2) (PBS). Coated. Each well was overcoated with Block Ace (Dainippon Pharmaceutical Co., Ltd., Osaka) diluted 4-fold with PBS. Before putting the antigen into the wells coated with the antigen, the test serum was pre-treated with PBS containing 1% BSA.
Dilute 00 times. After the test serum was placed in the wells and reacted, the anti-P antibody bound to the wells was detected by reacting with peroxidase-labeled F (ab ') ₂ goat anti-human IgG (Capel, Cochranville, PA). 10
In 0 ml of 0.05M citrate phosphate buffer (pH
4.8) O-phenylenediamine 40 mg and 30% H
A substrate solution containing 10 μl of ₂ O ₂ was added to each well, and reacted at 37 ° C. for 30 minutes. Then, the reaction was stopped by adding 5N H ₂ SO ₂ , and a two-wavelength microplate reader (MTP-12) was used.
0, Corona Electric, Ibaraki Prefecture).
A standard curve was prepared using anti-P antibody standard serum (Immunovision, Springdale, AZ) and OD492
The anti-P antibody was quantified by the unit mark from the value of.

On the ELISA plate, 1 / maximum absorbance
The anti-P antibody required to exhibit an absorbance of 2 was conveniently set at 1 U / ml. Using the same standard curve, non-specific binding to HSA was quantitatively determined by unit designation.
The specific anti-P antibody value was calculated by subtracting the value determined by the reaction to HSA alone from the value determined by the reaction to ribosome-HSA. The reproducibility of this measurement method was such that the intra-plate variation was 4.5% (CV
Value), plate-to-plate variation was 13.7%.

6) Western blotting Some SLE patient sera were examined for the presence of anti-P antibodies by Western blotting using HEp2 cell extracts. Specific binding of these sera to ribosome P peptide and non-specific binding to HSA / BSA / OVA were confirmed by Western blotting.
HSA · B with or without ribosome P peptide binding
After SA-OVA was electrophoresed on SDS polyacrylamide, it was transferred to a nitrocellulose membrane, and overcoated at room temperature for 2 hours in Block Ace diluted 4 times with PBS. Afterwards, the membrane is replaced with 0.05% Tween 20
SLE patient serum diluted 200-fold with PBS containing
The reaction was carried out at ℃ overnight. Thereafter, a peroxidase-labeled F (ab ') ₂ goat anti-human IgG (Kapelle) was added at room temperature.
The reaction was allowed to proceed for a period of time, and development was performed using an ECL system (Amersham, Tokyo).

7) Statistical Analysis The difference between the serum anti-P antibody titers in each group was determined by Mann-Whitney.
Tested using the U test. The positive rate of serum anti-P antibody in each group was analyzed by chi-square test. For changes in serum anti-P antibody titer due to treatment, see Wilcoxon signed r
Analyzed by ank test.

8) Specificity of ELISA method for measuring anti-P antibody In order to examine the specificity of the ELISA method for anti-P antibody,
The reactivity of the sera of six SLE patients with various carrier proteins bound or not bound to ribosome P-peptide was analyzed. Table 2 shows the results.

[0035]

[Table 2]

Eight sera in which the presence of anti-P antibody had been confirmed in advance by Western blotting using an extract of HEp-2 cells all reacted with the albumin-ribosome P-peptide complex (FIG. 1A). Serum of ribosome P
It also reacted with albumin itself that did not bind the peptide (FIG. 1B).

In FIG. 1, the study was carried out using ribosome P peptide-bound carrier protein (+) or carrier protein alone (-) (OVA = ovalbumin, BSA = bovine serum albumin, HSA = human serum albumin).

On the other hand, of the eight sera in which the anti-P antibody was negative by Western blotting using the HEp-2 cell extract, only three sera reacted with ribosome P peptide-bound and unbound albumin. Was. Therefore, it is found that an antibody against albumin exists in these sera, but no anti-P antibody exists.

It should be noted that all the eight sera which showed anti-P antibody positive by Western blotting using the HEp-2 cell extract showed positive values by ELISA (12
(1.6 to 1413.6 U / ml), all of the 8 sera which showed anti-P antibody negative by Western blotting with HEp-2, including 3 anti-albumin antibody positive, showed anti-P antibody negative value by ELISA. (0-17 U / ml). ELISA
P-HSA and ribosome PB as antigens
When using either SA or ribosome P-OVA,
No significant change was observed in the measurement of anti-P antibody. These results indicate that some SLE patients contain anti-albumin antibodies in their serum. However, the ELISA method established according to the present invention was confirmed to be specific for anti-P antibody.

9) Quantification of Anti-P Antibody by ELISA The anti-P antibody in the sera of 75 SLE patients was measured by ELISA.

As shown in FIG. 2A, serum anti-P antibody was found to be non-C in patients with lupus psychosis.
NS SLE patients or SLE showing nonpsychotic CNS
It was significantly higher than in patients. Among patients with lupus mental illness, there are 9 patients with cerebral organic syndrome and 19 patients with non-organic psychosis. However, serum anti-P antibody did not differ significantly between non-organic psychosis and organic brain syndrome. The broken line indicates the detection limit of serum anti-P (4 U / ml). The vertical bar indicates the mean ± standard deviation. Statistical analysis is M
Performed using the ann-Witney U test.

The anti-P antibody in the serum of 34 healthy subjects was 5.5
It was 2 ± 8.39 U / ml (mean ± standard deviation). Table 3
As shown in Table 2, only 2 (19.2%) of the 26 non-CNS SLE patients showed the upper limit of the normal anti-P antibody value (the standard anti-P antibody value of a healthy individual was 3 standard deviations). Doubled value). In lupus psychosis patients, the rate of abnormalities in serum anti-P antibody levels was significantly increased compared to non-CNS SLE patients or SLE showing nonpsychotic CNS (p
= 0.005, χ ² = 12.19, degrees of freedom = 2). these
The above results support the finding that an increase in autoantibodies against the C-terminal portion of the ribosomal P protein is significantly correlated with lupus psychiatric disorders. In addition, it was suggested that brain syndrome and non-organ psychosis have a common pathology involving anti-P antibody.

[0042]

[Table 3]

10) Changes in Serum Anti-P Antibody Due to Treatment In six patients with lupus psychiatric disease, improvement by central nervous symptom treatment and changes in serum anti-P antibody levels were examined over time (mainly 1 post-treatment). ~ 3 months).

As shown in FIG. 3, the serum anti-P antibody level was significantly reduced by the treatment (the statistical processing was performed by Wilcoxon signed r).
ank test). FIG. 4 shows the clinical course of one case of SLE showing lupus psychosis improved by treatment. In parallel with the improvement of central nervous system symptoms, anti-P antibody levels are also decreasing. Arrows indicate steroid pulse therapy (1 g / day for 3 consecutive days). Serum anti-P antibody shows a high value when the patient's condition worsens, and decreases with remission of the condition. Therefore,
It turns out that the serum anti-P antibody level is also effective as an index of the activity of the central nervous system lesion.

11) Measurement of anti-P antibody in cerebrospinal fluid of CNS lupus patients The results of anti-P antibody in cerebrospinal fluid also vary depending on the reporter. We have also attempted to measure anti-P antibody in cerebrospinal fluid of CNS lupus patients. CSF anti-P antibody is lupus psychiatric 12
Only one of these cases was observed, but none of the nine SLE cases showing non-psychotic CNS was observed. Therefore, it is considered that anti-P antibody in serum, not anti-P antibody in cerebrospinal fluid, plays an important role in the onset of lupus psychosis.

12) Summary In the present invention, special consideration was given to the specificity of the anti-P antibody ELISA by using a high-purity ribosome P peptide. The difference in the carrier protein that binds the ribosomal P peptide did not affect the measurement result as a result. However, by using human serum albumin (HSA), which is originally a human homologous protein, as a binding partner of ribosome P peptide, non-specific reaction hardly occurs, which is excellent in measuring anti-ribosome P antibody. Therefore, it is effective for the diagnostic agent of the present invention.

Furthermore, the results of the ELISA developed by us well correlated with the results of the Western blot using the HEp-2 cell extract, confirming that the specificity to the anti-P antibody is high. This highly specific EL
The use of ISA could support a significant correlation between lupus psychosis and anti-P antibodies. In addition, our results supported the conclusion that the previous pros and cons of the relationship between lupus psychiatric disease and anti-P antibodies were due to differences in the purity of the lysosomal P-peptide used in the assay.

On the other hand, as pointed out by Teh and Isenberg, it cannot be ignored that the methods and standards for diagnosing lupus psychiatric disorder are different in the prior art. These differences may reflect the difficulty of assessing the various neuropsychiatric symptoms in SLE. However, it is necessary to consider that SLE patients exhibiting neuropsychiatric symptoms have immunological abnormalities in the central nervous system supported by elevated CSF Ig Index and CSF IL-6. According to the present invention, SLE patients with lupus psychiatric and non-psychotic CNS have the CSFIg Index
Since these patients showed an increase in CSF IL-6 and CSF IL-6, it was confirmed that the central nervous system symptoms of these patients were caused by active SLE.

Further, as described above, in SLE, various symptoms are observed with abnormalities in higher brain functions, and the symptoms associated with abnormalities in higher brain functions include finger power, cognition, memory, and other factors. There is a tendency to be roughly divided into two types: "cerebral organ syndrome" characterized by impairment of intellectual function and "non-organic psychosis" characterized by symptoms such as neurosis, mania, depression, and schizophrenia. There is
No reports so far refer to the correlation between brain organ syndrome and anti-P antibodies. The results of the present invention clearly demonstrated that there was no significant difference in serum anti-P antibody values between brain syndrome and nonorganic psychosis. Therefore, it can be seen that the anti-P antibody does not determine the symptom specificity of mental symptoms.

It has been pointed out that the appearance of anti-P antibodies may have racial differences. In fact, two reports from Japan show a high anti-P antibody positive rate (30% and 42%). However, in the present invention, the positive rate of the anti-P antibody in the entire SLE patient was 28%. In the present invention, taking into account the fact that the proportion of patients with lupus psychiatry is intentionally high, the positive rate of serum anti-P antibody in all Japanese SLE patients is higher than in other countries. Very Hard to think.

In the present invention, an increase in serum anti-P antibody was observed when the activity of the psychiatric nerve of the patient was high, and when the symptoms were relieved by the treatment, the anti-P antibody level was reduced. Furthermore,
Observation over time in one patient showed that serum anti-P antibodies also declined in parallel with the treatment improving symptoms. These results indicate that anti-P antibody in serum is useful in monitoring the activity of central nervous system lesions in patients showing psychiatric symptoms, as in previous reports. However, it should be noted that the present invention also shows that the degree of increase in serum anti-P antibody levels does not necessarily reflect the severity of central nervous system lesions. For example, patients with active central nervous system lesions have serum anti-P antibody levels of 121.6.
In some cases, it may show U / ml, and in some cases, patients who are in the amelioration phase due to treatment may show serum anti-P antibody levels of 800.0 U / ml. These results indicate that the serum anti-P antibody level itself is not a useful marker for knowing the degree of central nervous system lesions, but rather one unique indicator of the presence of SLE neuropathy with common pathophysiology. You should think. It is necessary to clarify the factors of individuals who develop similar central nervous symptoms even with different anti-P antibody titers.

In the present invention, no increase in anti-P antibody in cerebrospinal fluid of a patient with lupus psychiatric disease could be recognized.

Rather, it is highly probable that anti-P antibodies in serum, but not in cerebrospinal fluid, play an important role in the development of lupus psychiatric disorders. However, at present no mechanism is known, and there is no actual evidence that serum anti-P antibodies are involved in the pathogenesis of lupus psychosis. In fact, the antigen to which the anti-P antibody binds exists in the cytoplasm, and IgG (antibody) cannot normally enter the cytoplasm. However, recent studies indicate that epitopes recognized by anti-P antibodies are present on the surface of nerve cells and various non-neuronal cells.

Therefore, it is highly possible that the anti-P antibody binds to such cells to impair its function. In this regard, it is also fully inferred that vascular endothelial cells of the central nervous system differ from general vascular endothelial cells with respect to expression of ribosomal P antigen, and are susceptible to damage by anti-P antibodies.

In summary, the results of the present invention indicate that differences in the purity of ribosomal P-peptides have led to pros and cons of the correlation between anti-P antibodies and lupus psychosis in the literature so far. By using a highly specific ELISA, we were able to confirm the correlation between serum anti-P antibodies and lupus psychosis (including both brain syndrome and nonorganic psychosis). Although further studies are needed, anti-P antibodies in serum separated from cerebrospinal fluid are involved in the development of diffuse central nervous system disorders. It should be noted that other factors involved in the development of lupus psychosis and factors that determine the specificity of neuropsychiatric symptoms need to be studied in the future. Finally, an examination of the mechanism by which anti-P antibody is produced is also important for elucidating the entire mechanism of the pathogenesis of lupus psychiatric disorders.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing immunoblotting reactions of anti-P antibodies (A and B) of sera of two representative SLE patients.

FIG. 2 is a diagram showing serum anti-ribosomal P antibody levels in CNS lupus.

FIG. 3 is a graph showing changes in serum anti-P values after treatment in 6 cases of lupus psychiatry.

FIG. 4 is a view showing the clinical course of an SLE patient exhibiting cerebral organic syndrome.

[Procedure amendment]

[Submission date] July 23, 1997

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (2)

[Claims] An agent for diagnosing systemic lupus erythematosus comprising a synthetic ribosome P peptide-albumin conjugate obtained by binding a synthetic ribosome P peptide containing 22 amino acids at the C-terminus with a purity of 99% or more to albumin. . 2. The diagnostic agent for systemic lupus erythematosus according to claim 1, wherein the weight ratio of the synthetic ribosome P peptide to albumin is from 10 to 300 to 100 to 500.