Reactive lymphoid cells ('Immunoblasts') in autoimmune and haematological disorders.

Reactive changes in the lymphoid cells are seen in patients with active rheumatoid arthritis and the degree of reactivity is related to the activity of the disease. The test may be useful as an early indication of relapse in autoimmune disease. Changes are also described in the lymphoid cells of the blood in patients with idiopathic thrombocytopenic purpura, which are identical with those seen in other autoimmune disorders, in infections, and following immunization. This provides supporting evidence for the autoimmune nature of this disease. In contrast with this, patients with aplastic anaemia have been found to have entirely normal lymphoid cell populations in the peripheral blood and provide no evidence that this condition has an autoimmune basis.