Introduction: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that affects almost all internal organs, among which circulatory system organs (CSO)

lesions are not only among the most common but also at the top of the list of causes of mortality. The tactics of treatment of patients with SLE without and in combination with CSO lesions are fundamentally different, and therefore, improving diagnostic methods will help to enhance the effectiveness of the management of this category of patients.

The aim of the study: To determine the diagnostic value of laboratory markers of syntropic lesions of the circulatory system organs in patients with systemic lupus erythematosus.

Materials and methods: The research included 125 patients with SLE with CSO lesions, among whom the vast majority were young women. Patients were stratified according to syntropy. Syntropic lesions were those whose frequency significantly increased with increasing severity of SLE: retinal angiopathy, capillaritis, Raynaud's syndrome, livedo reticularis, atherosclerosis, mitral valve insufficiency, mitral valve thickening, pericardial effusion, pulmonary hypertension, myocarditis, endocarditis, symptomatic arterial hypertension, and vein thrombosis. During the study, the diagnostic value of individual laboratory markers and their constellations in terms

of sensitivity, specificity, and accuracy in patients with SLE with syntropic lesions of CSO was determined step by step, and the one with the highest diagnostic value for the diagnosis of these lesions was chosen. The difference was considered statistically significant if p<0.050. The association coefficient and the contingent coefficient were used to determine the closeness of the relationship between the marker and the syntropic lesion. The relationship was considered confirmed if the association coefficient was ≥ 0.50 or the contingent coefficient was ≥ 0.30.

Results: We studied the diagnostic value of individual laboratory markers and their constellations in terms of sensitivity, specificity, and accuracy in patients with SLE with syntropic CSO lesions. It was found that the best diagnostic value for the diagnosis of retinal angiopathy is the constellation of ↑ LDL + ↑ IA + ↑ anti-ds DNA + ↑ ANA; capillaritis – ↑ β-globulins + ↑ IA + ↑ anti-ds DNA + ↑ antiphospholipid antibodies Ig M + ↑ anti-Sm + ↓ C4; Raynaud's syndrome – a separate marker ↓ C3; livedo reticularis – ↑ ESR + ↑ small CIC + ↑ anti-ds DNA + ↑ anti-Sm; atherosclerosis – ↓ hemoglobin + ↑ LDL + ↑ ANA + ↓ C4; mitral valve insufficiency – ↑ ESR + ↑ anti-ds DNA + ↑ ANA + ↑ antiphospholipid antibodies Ig M; mitral valve stenosis – ↑ ESR+↑ LDL + ↑ small CK + ↑ ANA; pericardial effusion – erythropenia + ↑ C-RP + ↑ lupus anticoagulant; pulmonary hypertension – hypercholesterolemia + ↑ LDL + ↑ anti-ds DNA + ↑ ANA; myocarditis – an individual marker ↓ C4; endocarditis – ↑ ESR + ↑ total fibrinogen + ↑ γ-globulins + hypercholesterolemia + ↑ anti-Sm; symptomatic arterial hypertension – ↑ LDL + ↑ anti-ds DNA + ↑ ANA + ↑ anti-SSA (Ro); vein thrombosis – erythropenia + ↓ hemoglobin + ↑ LDL + ↑ ANA.

Conclusions: For each syntropic lesion in patients with systemic lupus erythematosus, an individual laboratory marker or constellations have been identified that having the best diagnostic value for the diagnosis of these lesions.