JAK2 Mutation May Predict Response and Guide First Line Treatment in Rheumatoid Arthritis

PCR detection of the JAK-2 V617F mutation using ASO specific PCR Genetic marker:

The detection of jak2 V617F mutation were done by using the following primers (JAK2 Reverse: 5' CTGAATAGTCCTACAGTGTTTTCAGTTTCA 3', JAK2 Forward (specific): 5' AGCATTTGGTTTTAAATTATGGAGTATATT 3' and JAK2 Forward (internal control): 5' ATCTATAGTCATGCTGAAAGTAGGAGAAAG 3'). Cycling conditions were 35 cycles with annealing temperature 58.5oC flowed by agarose gel 2% electrophoresis for bands detections.

All patients started treatment by conventional synthetic DMARDs (including methotrexate). Response assessment at 3rd month was evaluated by DAS28 and ACR response criteria. JAK2 mutation was correlated with different clinical and laboratory parameters of patients.

The Disease Activity Score (DAS) and the DAS28 have been developed to measure disease activity in RA both in daily clinical practice as well as in clinical trials on a group as well as individual level. The DAS/DAS28 is a continuous measure of RA disease activity that combines information from swollen joints, tender joints, acute phase response and general health The DAS28 is a measure of disease activity in rheumatoid arthritis (RA). DAS stands for 'disease activity score' and the number 28 refers to the 28 joints that are examined in this assessment. questionnaires (e.g. the HAQ which assesses function), X-rays, and newer imaging techniques such as ultrasound and MRI.

The ACR20 is a composite measure defined as both improvement of 20% in the number of tender and number of swollen joints, and a 20% improvement in three of the following five criteria: patient global assessment, physician global assessment, functional ability measure [most often Health Assessment Questionnaire (HAQ)], visual analog pain scale, and erythrocyte sedimentation rate or C-reactive protein (CRP). ACR50 and ACR70 are the same instruments with improvement levels defined as 50% and 70% respectively versus 20% for ACR20.