The mean age of the studied patients was 14.46 ± 2.75 years, most of the included patients were females (92.2%), and the mean BMI was 25.23 ± 0.56 kg/m2.

The patients were subdivided according to the presence of AQP4-IgG Abs, with 56 (62.2%) patients who were positive and 34 (37.8%) patients who were negative for AQP4-IgG Abs. There was no significant difference between the groups with regard to age, sex, or BMI (Table 1).

Regarding clinical manifestations, our study revealed that the most common cutaneous manifestations were malar rashes (77.8%), ulcerations (56.7%), alopecia (40%), discoid lesions (20%), and photosensitivity (61.1%), with no significant difference between subgroups except for a significantly higher frequency of discoid lesions in the AQP4-IgG Ab-positive subgroup than in the AQP4-IgG Ab-negative subgroup (p = 0.039). The most common clinical manifestations in the studied patients were renal involvement (73.3%), neurological disorders, arthritis (65.6%), cardiac affection (57.8%), and serositis (51.1%), with a significantly higher frequency of renal involvement, neuropsychiatric disorders and cardiac affection in the AQP4-IgG Ab-positive subgroup than in the AQP4-IgG Ab-negative subgroup (P = 0.004, 0.001, 0.04, and 0.013, respectively) (data not shown in table).

Patients were divided on the basis of SLEDAI scores into (30.0%) mild, (25.6%) moderate, (32.2%) high, and (12.2%) very high disease activity subgroups, where the mild disease activity subgroup had SLEDAI scores of 1 to 5, the moderate disease activity subgroup had SLEDAI scores of 6 to 10, the high disease activity subgroup had SLEDAI scores of 11 to 19, and the very disease high activity subgroup had SLEDAI scores ≥ 20 [12]. A comparison of subgroups revealed a significantly higher frequency of high and very high scores in the AQP4-IgG Ab positive subgroup than in the negative subgroup (P < 0.004).

There was a significantly higher frequency of seizures and psychosis (P = 0.032 and 0.009, respectively) and a trend (approach significant) towards a higher frequency of headache, anxiety, and cranial neuropathy in the AQP4-IgG Ab-positive subgroup than in the AQP4-IgG Ab-negative subgroup (P = 0.065, 0.065, and 0.08, respectively). However, there was no statistically significant difference between subgroups regarding other neuropsychiatric manifestations (Table 1).

A statistically significant lower median concentration of C3 and a higher frequency of proteinuria in the AQP4-IgG Ab-positive subgroup than in the AQP4-IgG Ab-negative subgroup were observed (P = 0.009 and 0.004, respectively). There were trends towards a higher prevalence of LA and ACL positivity in AQP4-Ab positive patients, but these differences were not statistically significant (P = 0.067 and 0.07, respectively). There was no statistically significant difference among subgroups regarding the remaining laboratory investigation parameters, including the WBC count, neutrophil number, lymphocytes number, HB level, platelet count, MPV, ESR, CRP, C4, ANA positivity, and anti dsDNA. The number of patients who needed an echocardiographic examination and the prevalence of pericarditis were significantly higher in the AQP4-Ab-positive subgroup than in the AQP4-Ab-negative subgroup (P = 0.013 and 0.018, respectively). There was no statistically significant difference between the two subgroups regarding myocarditis, endocarditis or a valvular effect (Table 2).

Regarding renal biopsy results, there was no statistically significant difference between the two subgroups regarding disease activity, chronicity index of renal biopsy, and the prevalence of LN classes (Table 3).

In this study, the most common brain MRI findings were white matter hyperintensities (53.3%), white matter parenchymal defects (10%), white matter atrophy, and cerebellar hyperintensities (7.8%). The prevalences of white matter hyperintensities and white matter atrophy were significantly higher in the AQP4-Ab-positive subgroup than in the AQP4-Ab-negative subgroup (P = 0.008 and 0.032, respectively). However, there was no statistically significant difference between subgroups regarding hyperintensities or parenchymal defects (grey matter, basal ganglia, and cerebellum) (Figs. 1, 2).

Studying the protocols of therapy, we noticed that 86.7% of the patients were receiving maintenance therapy of chloroquine; 70% were receiving cortisone, and 26.7% had been taking cortisone for less than one week; 61.1% were on a cyclophosphamide protocol, and 16.7% had just started their first dose; 34.4% were receiving methotrexate; 24.4% were receiving azathioprine; 32.2% were on an MMF protocol; 57.8% were receiving maintenance antihypertensive medication; 31.1% were receiving maintenance antiepileptic therapy; anticoagulant medications were prescribed to 15.6% of the studied patients and aspirin to 24.4%; and 15.6% had received plasmapheresis. Among the patients, 42.2% did not adhere to their drug therapy, which may be related to a lack of awareness about jSLE complications and the rebellious behaviour of adolescents, which could be aggravated by the mood disorders associated with the disease. There were significantly higher frequencies of maintenance therapy of chloroquine, antiepileptic drugs, cyclophosphamide, azathioprine, plasmapheresis, and drug nonadherence in the AQP4-Ab-positive subgroup than in the AQP4-Ab-negative subgroup (P = 0.027, 0.032, 0.028, 0.029, 0.049, and 0.018, respectively). There was a trend towards a higher frequency of cortisone prescription in AQP4-Ab-positive patients, but the difference was not statistically significant (p = 0.06). A statistically insignificant difference was found between the groups regarding methotrexate, MMF, antihypertensive medications, anticoagulant medications, and aspirin prescription.

Demonstrates neuropsychiatric manifestation studied in the current JSLE series. CVD: cerebrovascular disease, MG: myasthenia gravis, GB: Guillain-Barré. (CVD: cerebrovascular disease, MG: myasthenia gravis, GB: Guillain‒Barré syndrome)

MRI findings in the AQP4-IgG Ab-positive and AQP4-IgG Ab-negative subgroups. WM: white matter, GM: grey matter, BG: basal ganglion, BS: brain stem, C: cerebellum

The prevalences of white matter hyperintensities and white matter atrophy were statistically significantly higher in the AQP4-Ab-positive subgroup than in the AQP4-Ab-negative subgroup (P = 0.008 and 0.032, respectively). However, there was no statistically significant difference between subgroups regarding hyperintensities or parenchymal defects (grey matter, basal ganglia, and cerebellum).