ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES (ANCA) IN MYELODYSPLASIA AND OTHER HEMATOLOGICAL DISORDERS

Background: Anti-neutrophil cytoplasmic antibodies (ANCA) are typicall y associated with small vessel vasculitides. They are also found in si tuations where other autoantibodies are common, sometimes after infect ions and possibly in individuals who have received multiple blood tran sfusions. Aims: The aim of this study was to determine the incidence o f ANCA in a variety of haematological disorders, where these predispos ing factors may be at work. Methods: Sera from patients with myelodysp lasia (n = 26), acute myeloid leukaemia (AML) (n = 3), and myeloprolif erative (n = 25) or lymphoproliferative syndromes (n = 16) were screen ed for ANCA using a crude neutrophil cytoplasmic extract ELISA and ind irect immunofluorescent examination of normal peripheral blood neutrop hils. Positive results were confirmed by ELISAs for anti-proteinase 3, anti-myeloperoxidase or anti-elastase antibodies. Results: ANCA were demonstrated in two patients with myelodysplasia, both with chronic my elomonocytic leukaemia and greater than 5% blasts in the bone marrow. Both of these individuals were infected at the time that ANCA were dem onstrated and other autoantibodies were present. One of these individu als had never had evidence of any vascultis; the other probably develo ped myelodysplasia after treatment with cyclophosphamide for Wegener's granulomatosis. ANCA were demonstrated in one individual with AML sec ondary to myelodysplasia. ANCA were also found in a patient with lymph oma in whom autoantibodies against red cells and platelets were alread y noted. ANCA were demonstrated in one further individual with lymphom atoid granulomatosis, a condition that resembles Wegener's granulomato sis clinically and histologically, but which is treated as a lymphoma. No ANCA were present in any of the patients with myeloproliferative s yndromes.