Dear, my cousin Dr.Faisal Alshamiry. I hope that you are fine.As you know that your question is regarded as a wide range issue. Anyhow, I think that immunity level measurements are type dependant on the pathogens or the test you are going to be studied. Nevertheless, you can measuring the elements of blood levels through the cellular components especially WBCs differential count and in correspond to the neutrophils type, as well as, for ( B and T ) lymphocytes. While, for vehicles blood level measurements, you can estimate depending on case (test) manner studies. In generally for the Interleukins ( ILs ), Inflammatory mediators, TNF, INF etc.... that are in away or another is a such of dependant types.
Book: П.Ф. Забродский, В.Г.Мандыч. Иммунотоксикология ксенобиотиков. Саратов, СВИБХБ. 2007. 420 p. P.F. Zabrodskii, V.G.Mandych. Immunotoxicology of xenobiotics. Saratov, Saratov Military Institute of Biological and Chemical Safety, 2007. 420 p.