R. Billström (Y) 7 T. Olofsson Divison of Haematology, Department of Medicine, University Hospital, S-22185 Lund, Sweden B. Johansson 7 B. Strömbeck 7 F. Mitelman Department of Clinical Genetic, University Hospital, Lund, Sweden W. El-Rifai 7 M. Larramendy 7 S. Knuutila Department of Medical Genetics, University of Helsinki, Helsinki, Finland Ann Hematol (1997) 74 : 37–40 Q Springer-Verlag 1997 CASE REPORT R. Billström 7 B. Johansson 7 B. Strömbeck W. El-Rifai 7 M. Larramendy 7 T. Olofsson F. Mitelman 7 S. Knuutila Clonal CD5-positive B lymphocytes in myelodysplastic syndrome with systemic vasculitis and trisomy 8 Received: 2 September 1996 / Accepted: 17 October 1996 Abstract Bone marrow and peripheral blood from a myelodysplastic syndrome (MDS) patient with trisomy 8 and associated systemic vasculitis was investigated for clonal lymphoid lineage involvement using simulta- neous metaphase and interphase fluorescence in situ hybridization (FISH) and immunocytochemistry with antibodies against CD13 (granulocytic), glycophorin A (GPA, erythroid), and the lymphocytic antigens CD3, CD5, CD20, and CD22. Trisomy 8 was detected in 55% of CD13c, 40% of GPAc, 6% of CD5c, and 5% of CD20/22c, but not in CD3c cells. In a complementa- ry experiment using interphase FISH on bone marrow cells sorted by flow cytometry, 13% of CD5/CD19 dou- ble-positive cells (76% purity) were found to be tri- somic. The results indicate the existence of a small CD5-positive B-lymphoid clone as part of the MDS process in this patient. Since CD5/19-positive cells have been proposed to be autoantibody producing, this find- ing might be a clue to the pathogenesis underlying the propensity for MDS patients to develop immune-me- diated complications. Key words MDS 7 Vasculitis 7 Lymphoid cells 7 Trisomy 8 7 CD5/CD19 Introduction Immune-mediated complications (IMC) develop in ap- proximately 10% of patients with myelodysplastic syn- dromes (MDS), skin vasculitis with or without systemic symptoms being the most common clinical manifesta- tion [4, 5]. The pathogenetic mechanisms underlying the association between MDS and IMC are unknown. Autoimmunity caused by clonal lymphoid cells derived from multipotent MDS stem cells has been suggested [7], but no experimental data to support this proposi- tion have, as yet, been forthcoming. Combining cyto- genetic and immunocytochemical methods, we have studied clonal involvement of lymphoid subsets in a pa- tient with MDS associated with vasculitis. Case report MDS, refractory anemia without excess of blasts, was diagnosed in 1991 in a 54-year-old man. He had undergone surgery and ra- diotherapy 21 years previously for a testicular seminoma. At the time of MDS diagnosis, the patient’s blood counts were: hemoglo- bin 11.8 g/dl, MCV 123 fl, WBC 2.7!10 9 /l (52% neutrophils, 4% eosinophils, 0% basophils, 33% lymphocytes, and 11% mono- cytes), and platelets 187!10 9 /l. The bone marrow smears showed dyserythropoiesis, granulocytopoietic dysplastic changes, and 1% myeloblasts. The bone marrow karyotype, which has been pub- lished previously [4], was 47,XY,c8[10]/46,XY[9]. The man was followed without therapy. In 1992, he was hospitalized for 5 weeks due to pyrexia, lower-extremity edema and erythema, pru- ritus, aphthous oral ulcerations, pleural effusion, and a right cer- vical lymphadenopathy. Extensive investigations to determine in- fectious causes were negative. During the following year, bouts of oral ulcerations, fever, and pruritus recurred. A biopsy from a buccal ulceration showed only unspecific inflammation. Treat- ment with cyclosporine was initiated on the clinical suspicion of vasculitis, but after 4 months this was considered ineffective. At this time, histopathological examination of a skin biopsy from a papulous lesion verified a pattern of lymphocytic vasculitis. Ther- apy with 60 mg prednisolone daily, previously avoided due to ra- diographic evidence of osteoporosis, had an excellent effect. However, symptoms recurred at a prednisolone dose below 20 mg daily. Currently, the patient is being treated with 100 mg azathio- prin and 5 mg prednisolone daily. Occasional episodes of fever, pruritus, and oral ulcerations require a raised prednisolone dose.