Determination of antinuclear antibodies: role in modern differential diagnosis of connective tissue autoimmune diseases

There is an increase in autoimmune rheumatic diseases among all age population groups globally. Diagnosis is often difficult, because the early stages of the diseases usually do not have specific symptoms. Often, clinical manifestations of autoimmune diseases and non-autoimmune pathologies have similar symptoms. Therefore, the differential diagnosis could be very difficult. Most often, the determination of antinuclear autoantibodies is used for laboratory diagnosis of connective tissue systemic diseases. Autoantibodies can be detected in patients long time before the appearance of symptoms. The correct diagnosis is very important because the therapy of various nosologies can be different. It is especially significant with the invention of targeted therapy. Further analysis of the diagnostic value of autoantibody determination is very important. This article presents examination and follow-up data of three children. The analysis of medical documentation was carried out. The role of determining autoantibodies in the differential diagnosis of autoimmune connective tissue diseases was analyzed. In the first patient with Sjögren’s syndrome, the clinical picture of the underlying disease developed at least 5 years after the detection of high levels anti-SS-A, SS-B and Ro-52 antibodies (immunoblotting) and the speckled pattern (indirect immunofluorescence assay). In the second patient, antibodies against centromeres (specific markers of systemic scleroderma) appeared at least 2 years before clinical symptoms. In the third patient, the specific markers of systemic scleroderma have been detected for 5 years. There were antibodies against centromeres (immunoblotting), high titer and the centromere pattern (indirect immunofluorescence assay). However, the patient has not developed any clinical symptoms of this disease during all time of observation. Thus, the analysis of the presented clinical cases shows that autoantibodies can be detected in patients long time before the onset of clinical manifestations of a specific autoimmune disease. In all three cases, the first immunological examination has been carried out in the background of the disease symptoms, but they were atypical. Identification of specific autoantibodies, is very important for differential diagnosis. In the absence of clinical symptoms, the presence of autoantibodies, is the reason for dynamic observation of the patients.