Background:Serum amyloid A protein (SAA) likely has a critical role in control and possibly propagation of the primordial acute phase response and is the precursor of AA amyloid fibrils. Prolonged elevations in SAA are the major inciting factor for AA amyloidosis developing in chronic inflammatory diseases. In Russia 2-4% of patients with ankylosing spondylitis (AS) have secondary (AA) amyloidosis.Objectives:To study the level of SAA in AS its relationship with indicators of disease activity.Methods:124 patients with AS (according to mNYC 1984) 70 men, 54 women, of whom HLA B 27 positive 91.1% mean age 38.1 (± 12.9), age at the onset of the disease 23.5 (± 9.9) consecutively admitted to the clinic of the Research Institute rheumatology from February to November 2020. In addition to the standard examination (the median CRP 6.7 mg/l [1.4; 24.9], ESR 13 mm/h [7; 27], SAA was studied in all patients by the nephelometric method.Results:The median SAA in 124 patients was 12.5 mg/l [4;71.6]. Among them, 31% had normal SAA level (<5 mg/l), and 69 % - more than 5 mg/l. In 21 (17.5 %) cases, the level of SAA was increased at normal CRP levels, and only in 2 cases an increase in the level of CRP at normal SAA levels; 50 patients (40.3 %) with normal ESR had elevated SAA levels, and 7 (5.6%) - ESR exceeded the upper limits of the norm with normal SAA levels. Comparison of the average values of the levels of SAA, CRP, ESR in men and women did not reveal significant differences between them. The SAA level was weakly correlated with ESR (r = 0.2; p=0.002) and BASDAI (r=0.3; p=0.002), moderately with ASDAS-CRP (r=0.5; r<0.0001), but showed a strong association with CRP (r = 0.80; p<0.00001). Patients with elevated SAA levels (>5 mg/l) had a shorter disease duration (10 and 12 year; p<0.0004), higher ASDAS-CRP (2.9 and 2.4; p<0.003), blood CRP level (14.6 and 1.3; p<0.00001), and significantly more peripheral arthritis (60% and 39%; p<0.05) than patients with normal indicators.Conclusion:The level of SAA correlates well with indicators of AS activity, especially with the level of CRP, and can be used as an alternative indicator of disease activity.Disclosure of Interests:None declared

Background:Spinal damage with limited mobility requires the search for diagnostic methods that allow us to accurately and quantitatively assess the developing decline in function and track this change in dynamics. One of these possible methods is ultrasound examination of the spine, which was recently described in the article Yurdakul O. V. [1].Objectives:to study the possibility of using ultrasound for dynamic monitoring of sagittal mobility of the spine in ankylosing spondylitis (AS).Methods:Ultrasound of the spine was performed in 15 patients with AS according to the method described in the article Yurdakul O. V. - determination of the sonographic distance between the spinous processes C5-C6, Th11-Th12 and L4-L5 of the vertebra (initial - vertical position, and when tilted - maximum sagittal flexion). All patients underwent a double examination: at inclusion in the study and after 2 weeks. The average age of the patients was 40.8±11.4 years, and the average duration of the disease was 5.5±3.5 years. 93.3% of patients were positive for HLA-B27. All patients were treated with nonsteroidal anti-inflammatory drugs, and 9 (60%) had biological therapy. The differences (Δ) between the indicators obtained on the first day and after 2 weeks - were calculated and further compared.Results:During 2 weeks of follow-up, ESR practically did not change (it was 16 [6;48], after 2 weeks 14 [6;27], p=0.45), CRP decreased by 3.5 times (22.3 [2.5;40.5] and 5.9 [3.0;23.7], p=0.4), BASDAI (7.2-3.1,p=0.003), ASDAS-CRP (3.7-2.2,p=0.001) and BASFI (5.5-2.5, p=0.001), but not BASMI 10 (24-22, p=0.18). There were also no significant changes in mobility indicators according to sonographic measurements for 2 weeks. However, the correlation analysis of the dynamics of indicators for the study period showed the following results (see the Table 1):Table 1.Correlation (r) between spinal ultrasound parameters and AS activity indices and metrological indices at the beginning of the study and after 2 weeks.Δ of the indicatorsΔiС5-С6ΔsС5-С6ΔiTh11-Th12ΔsTh11-Th12ΔiL4-L5ΔsL4-L5ΔESR-0.5*-0.4*-0.3-0.2-0.5*-0.4*ΔCRP-0.3-0.1-0.4-0.5-0.4*-0.7*ΔASDAS-0/4-0.50.1-0.30.10.2ΔBASDAI-0.2-0.1-0.2-0.3-0.3*-0.5*ΔBASFI-0.6*-0.5*-0.50.20.3-0.3ΔBASMI 10-0.2-0.1-0.2-0.3-0.3*-0.5*Note: *-p<0.05, Δi - C5-6, Th11-12, L4-5, mm – the difference between the indicators obtained by ultrasound in the vertical position at admission and after 2 weeks, Δs – the difference between the indicators at maximum sagittal flexion.A correlation was found between an increase in the interspinous distance in the cervical and lumbar spine and a decrease in the level of ESR, and in the lumbar spine - with CRP. There is also a significant relationship between the activity of AS according to the BASDAI index and the mobility of the spine at the level of L4-5, which was manifested by an increase in the interspinous distance with a decrease in the activity of the disease. Sonographic measurements of all three levels of the spine show a negative correlation with the combined metrological index BASMI 10, most significantly with the L4-5 level of the spine.Conclusion:The method of ultrasound examination of spinal mobility in AS allows not only to objectify the indicators, but can also be used to monitor the function of the axial skeleton during follow-up.References:[1]Yurdakul APA, e.a. Medicine: September 2018; doi: 10.1097/MD.0000000000012609.Disclosure of Interests:None declared.

Serum amyloid A protein A (SAA) is a normal serum protein (serving as a precursor of fibrillar tissue protein AA), synthesized in the liver and a rapidly responding marker of the acute phase of inflammation. A constant high concentration of SAA is one of the factors in the development of AA-amyloidosis. As a rule, secondary amyloidosis develops in patients with long-term and poorly controlled inflammatory diseases, including rheumatic diseases, one of which is ankylosing spondylitis (AS).Objective: to assess the level of SAA in AS patients and its relationship with indicators of disease activity.Patients and methods. The study included 124 patients with AS who met the modified New York 1984 criteria. The disease activity and functional status of patients were assessed according to the recommendations of Russian experts. SAA and CRP, ESR in blood serum were measured in all patients.Results and discussion. The median SAA concentration was 12.5 mg/L [4; 71.6]. Of 124 patients, 31% had SAA levels <5 mg/L and 69% had >5 mg/L. A strong correlation was found between the levels of SAA and CRP (r=0.80, p<0.000001), no significant relationship was found between SAA and ESR (r=0.31, p=0.92). The correlation between the AS activity according to the BASDAI index and SAA was weak (r=0.3, p<0.002), the correlation with ASDAS-CRP was moderate (r=0.54, p<0.00001).Conclusion. A statistically significant relationship was found between SAA and CRP levels, as well as the AS activity indices. Research has shown that SAA can be used as one of the markers of inflammation in AS.

Background:Ankylosing spondylitis is a chronic systemic inflammatory disease. Inflammation and high levels of serum amyloid A (SAA) protein are predisposing factors for secondary AA amyloidosis. The role of SAA1 gene polymorphisms in AS is not well understood.Objectives:To investigate the association of SAA1 gene polymorphism -13T/C (rs12218) with ankylosing spondylitis and to evaluate the influence of this polymorphism on SAA protein concentration.Methods:123 AS patients (72 males, 51 females; age - M (SD) 37.51 (12.77) years; disease duration - 14.28 (11.22) years; BASDAI – 5.59 (1.13); B27-positive - 111 (90.2%) pts) and 95 gender, age matched healthy individuals (control group) were included in this study. SAA1 gene polymorphism -13T/C was genotyped using allele-specific RT-PCR assay. SAA protein concentration was measured using nephelometry in AS patients.Results:The distribution of genotypes TT, TC and CC differed statistically between AS and control groups (24.4%, 56.1%, 19.5% and 41.1%, 44.2%, 14.7% respectively, χ 2=6.9, p=0.03).The presence of the C allele was associated with the development of AS (OR=1.55 [CI 1.04-2.33], p=0.03). The SAA1 -13T/C polymorphism tended to be associated with SAA protein value in AS patients: TT+TC genotypes -13.8 mg/l [4.2; 91.0], CC genotype -7.8 mg/l [1.6; 29.6], p=0.07. ESR, CRP and BASDAI values did not correlated with SAA1 - 13T/C polymorphism (p=0.6, p=0.4, p=0.4 respectively).Conclusion:The results of our study demonstrated for the first time that SAA1 gene polymorphism -13T/C (rs12218) is associated with susceptibility to AS. It is also shown that this polymorphism can affect the SAA protein level. Our findings need to be verified in AS patients with high levels of SAA protein in various ethnic and population groups.Disclosure of Interests:None declared

Spine involvement in ankylosing spondylitis (AS) resulting in limited mobility requires a search for accurate, quantitatively methods of assessment of the decline of its function and monitoring of its dynamics. One of the promising methods for assessing movements in the spine in AS is ultrasound examination (US).Objective: to determine the relationship between the mobility of the spine measured sonographically, and the activity and functional status of patients with AS.Patients and methods. Spinal ultrasound was performed in 15 patients (10 men and 5 women, mean age 40.8±11.4 years, mean duration of the disease 5.5±3.5 years) with a confirmed diagnosis of AS, admitted to the V.A. Nasonova Research Institute of Rheumatology from April to August 2019. All patients underwent a double examination (at baseline and after 2 weeks) according to a specially developed protocol.Results and discussion. A comparative analysis of the results of sonographic measurements of the distance between the spinous processes of the vertebrae of the studied spine segment at baseline and after 2 weeks revealed a tendency towards an increase in these parameters both in the initial position and during flexion. There was no relationship between age, body mass index, duration of the disease and the distance between the spinous processes in all parts of the spine measured by sonography in initial position and during flexion. Correlation analysis data indicate the presence of a correlation between an increase in the distance between the spinous processes in the cervical and lumbar spine and a decrease in ESR, and i increase in the distance between the spinous processes in the lumbar spine and level of CRP. A weak negative relationship was found between the BASDAI index and the mobility of the spine at the LIV–V level and between sonographic measurements in all segment of the spine and the BASMI index.Conclusion. The sonographic method of determining the mobility of the spine can be recommended in patients with AS, both for initial examination and during follow-up, but it can't substitute the BASMI metrological index. Further research is needed to confirm the findings.