Toxoplasma gondii infection in patients with rheumatoid arthritis and systemic lupus erythematous diseases: serological and molecular evidence.

This study aimed to determine Toxoplasma gondii infection in rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) patients in Mazandaran Province, north of Iran. During April 2019 to February 2020, 305 patients with RA (N=272) and SLE (N=33) diseases are included in this cross-sectional study. The baseline data of patients were collected into a questionnaire. Also, blood sample was taken from each patient in tubes containing k2-EDTA as anticoagulant for serological and molecular analyses. The presence of specific IgG antibody against T. gondii in plasma was explored using ELISA method. DNA was extracted and conventional-PCR method was done using RE primers on buffy coat samples. Anti-Toxoplasma IgG were detected among 105/272 RA (38.6%) and 11/33 (33%) SLE patients (P=0.55). IgG seropositivity was more common in females (95.70%) than in males (4.30%) and in 51-60 years old patients (37.10%) in rural populations (62.07%). Also, seropositivity was higher in patients who kept cats (93.95%). Keeping cats and patient's age were two studied risk factors which had significant relations with T. gondii seropositivity in patients (P<0.05). Overall, T. gondii DNA was found in 60 of 305 (19.7%) of enrolled patients, whether serology positive or negative (P<0.0001). Given the RA and SLE patients can be considered as a risk group for toxoplasmosis, in addition to the serological test, PCR based techniques is recommended for early and accurate detection of recent T. gondii infection.