Analysis of immunologic and haematological parameters for diagnosis of autoimmun diseases in patients with joint pains in a university hospital

Purpose: Joint pains that are observed by environmental or structural reasons, are one of the most prevalent diseases in the society. In Systemic Autoimmune Diseases, it is very common for patients to complain of joint pain due to widespread involvement of the joints and this complaint is the reason for admission to the hospital. In the diagnosis and treatment of these diseases autoantibody tests have great importance. For this reason, Antinuclear antibody (ANA) tests are frequently used and they are known as gold standard diagnosis tests. Also for diagnosing autoimmune diseases Anti-CCP (Anti-Cyclic citrullated peptide) antibodies, RF (Rheumatoid Factor) antibodies and ESH (Erythrocyte Sedimentation Rate), CRP (C- reactive protein) can be commonly examined. In this study, we aimed to investigate the relationship between immunological and hematological laboratory test results for supporting the diagnosis of autoimmune diseases in our university hospital. Therefore, first we aimed to determine the frequency, titer and pattern distribution of first ANA IIF (Indirect Immunofluorescence) test positivity and then aimed to investigate the relationships between gender, other laboratory parameters such as ESH, CRP, RF and ANA, anti-CCP. Material and Method: Our study is a retrospective descriptive type research. The data in our study belongs to 848 patients with ANA IIF and Anti-CCP tests who applied with the complaint of joint pain to the Namık Kemal University Faculty of Medicine Hospital between January 2018 and September 2022. The study has been conducted with two stages. In the first stage, the patients have been grouped by evaluating the ANA IIF and Anti-CCP test results of them. Patients with positive ANA nuclear pattern have been examined in terms of their patterns and titers according to nuclear pattern positive and Anti-CCP positivity. In the second stage, patients have been divided into 6 groups according to the ANA and Anti-CCP: positive in terms of ANA nuclear pattern, ANA positive for cytoplasmic/mitotic pattern and negative for ANA, Anti-CCP positive and Anti-CCP negative. The data has been compared in terms of gender, ESH, RF and CRP positivity between these groups. Results: We found 585 (69%) patients with positive ANA IIF and 268 (31.6%) patients with positive Anti-CCP test. The 517 patients (88.4%) in the ANA positive group and the 226 patients (84.3%) in the anti-CCP positive group were women. It was found that the 181 fine speckled pattern (31.5%) was the main nuclear staining pattern (AC-4). ANA nuclear pattern titer is +1 with a maximum of 320 (55.6%) titer determined. The autoantibody positivity was observed more frequently in female groups especially in ANA nuclear pattern positive groups than the values in anti-CCP positive groups. We found that there was a significant relationship between RF positivity and anti-CCP positivity (p<0,05). Since the positivity of ESH and positivity of CRP was maximally observed in the group with positivity of ANA nuclear pattern and anti-CCP, a cumulative effect was found. Moreover, we reported a significant correlation between positivity of anti-CCP and positivity of ESH, CRP (p<0,05). Conclusion: The patients with joint pain complaints, the laboratory tests (immunological and hematological) are important for diagnosis and treatment. In our study, the ANA, Anti-CCP, RF, ESR and CRP data were evaluated. It was found that there was a significant correlation between RF, ESH, CRP positivity and Anti-CCP positivity. For future studies, prospective studies with a larger number of patients and a control group recommended. Keywords: Joint pain, Autoimmune disease, ANA, Anti-CCP