Diagnostic Sensitivity of Anti-cyclic Citrullinated Peptide ACCP2 and Rheumatoid Factor Isotypes RFs in Sudanese Rheumatoid Arthritis RA Patients.

The early diagnosis is essential, as it has been observed that progression occurs within 2 years of disease onset.. An aggressive intervention with new and effective biological treatments can alter the course of the disease, prevent joint destruction, lengthen life, and improve function . RA is known to be associated with broad range or the presence of a large number of autoantibodies The present study was designed as a case-control study, carried out in the National Ribat University Hospital, in Khartoum State, Sudan. The aim of this study was to assess the diagnostic value of RA serological markers. The study group composed of 88 patients with RA; all patients had fulfilled the criteria of the American College of Rheumatology (ACR) (5), whereas control group composed of 53 healthy individuals. Blood samples were collected from the study population in order to determine RF-isotypes namely (RF-IgM, RF-IgA), and ACCP2. RF-isotypes and ACCP2 were measured quantitatively using a Sandwich Enzyme–Linked Immunosorbant Assay ELISA (Euroimmune, Germany). displayed that 56.8% of the study group had positive RF-IgM, where it was 22.6% in control group. RF-IgA showed positive reaction in 47.7% and 30.2% of study group and control group, respectively Both RF-isotypes were found to be positive in 33(37.5%) and 6(11.3%) of study group and control group respectively. The ACCP2 was found positive in 52(59.1%) of study group and in 3(5.7%) of control group (table 2). The mean value of ACCP2 in RA patients was statistically significant than that of control group (p.value =0.000). Sensitivity for RA was highest for ACCP2 59%, followed by RF-IgM 56.82%. Utility of two combined RF-isotypes autoantibodies sensitivity for RA was 69(78.4%) and will be 90.9% when ACCP2 was enrolled with the 2 RF-isotypes. In this study 11(12.5%) patients were RF-isotypes negative and positive for ACCP2. Correlation between ACCP2 & RF-IgM was 0.386 and was 0.255 between ACCP2 and RF-IgA and there was no such correlations with the controls. This study showing that the ACCP2 had slightly better sensitivity than RFs among RA patients, and the diagnostic sensitivity of RA increased when ACCP2 was added in the panel along with RF-isotypes.