o In this moment, a blood test will be performed in all study patients including: Full blood count, basic biochemistry analysis, Iron metabolism parameters: total iron-binding capacity, total serum iron, ferritin and transferrin. Nutritional parameters. Inflammatory markers: C-reactive protein and erythrocyte sedimentation rate. Serum immunoglobulin levels, serum complement levels (C3 and C4) and peripheral blood lymphocyte subpopulations.