Background/Purpose: Although several autoantibodies of Neuropsychiatric Systemic Lupus Erythematosus (NPSLE) have been reported, none of these autoantibodies were conclusively established as pathogenic. We have reported that autoantibodies to triosephosphate isomerase (TPI), which is an important glycolytic enzyme in red blood cells or neuronal cells, are associated with NPSLE pathogenesis. We have detected the presence of anti-TPI antibodies in sera of human NPSLE patients. However, clinical features regarding anti-TPI antibody-positive NPSLE patients are not known. The aim of this study was to determine the clinical features of anti-TPI antibody-positive NPSLE patients.

Methods: Clinical data was retrospectively collected from 24 NPSLE patients (mean age: 26.41 ± 8.93 years old, 4 males and 20 females). NPSLE manifestations were determined according to the ACR case definitions for NPSLE. NPSLE patients were divided into 2 groups (anti-TPI antibody-positive or negative), and compared clinical features as follows: age, sex, disease duration, NPSLE manifestation, other SLE manifestations, SLEDAI, and laboratory data. Serum samples collected from all NPSLE patients were analyzed by Western blotting to detect anti-TPI antibodies using rabbit muscle TPI protein.

Results: 7 of 24 NPSLE patients were positive for anti-TPI antibodies (29.1%). Age, the rate of female, and SLEDAI were not significantly different between 2 groups. In Laboratory data, the platelet count was significantly elevated in anti-TPI positive NPSLE patients (221,800 vs 158,300  /μl, p = 0.047). In NPSLE manifestation, Lupus headache was more frequently observed in anti-TPI antibody-positive NPSLE patients (28.5% vs 0%, p= 0.012) (Table). The frequency of Seizure, Organic Brain Syndrome and Psychosis was similar in both groups in this study. Myelopathy and aseptic meningitis were observed only in anti-TPI antibody-negative NPSLE patients.

Conclusion: General clinical features were similar between anti-TPI antibody-positive NPSLE patients and negative patients, however, anti-TPI antibody-positive patients may have higher platelet count and higher frequency of lupus headache, compared to anti-TPI antibody-negative NPSLE patients.

Table. Clinical features of anti-TPI antibody-positive NPSLE patients.

 

Clinical items	Anti-TPI positive	Anti-TPI negative	p
number	7	17	–
Age (years old)	30.85 ± 9.7	24.58 ± 8.2	0.16
Sex (female %)	100%	76.5%	0.08
SLEDAI	16.42 ± 7.82	15.41 ± 6.51	0.76
Laboratory Data
WBC /μL	7857 ± 7054	6688 ± 3905	0.69
Hemoglobin g/dL	11.17 ± 3.25	11.17 ± 2.40	0.99
Platelet /μL	22.18 ± 6.05	15.83 ± 7.49	0.04
C3mg/dL	67.71 ± 44.8	56.11 ± 26.98	0.54
C4mg/dL	15.14 ± 14.95	13.76 ± 9.29	0.82
NPSLE manifestation
Seizure	42.8%	23.5%	0.17
OBS	14.3%	23.5%	0.31
Psychosis	28.5%	17.6%	0.27
Headache	28.5%	0%	0.01

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/clinical-features-in-patients-with-anti-triosephosphate-isomerase-antibody-positive-neuropsychiatric-systemic-lupus-erythematosus/