['Myelodysplastic syndrome (MDS) is a clonal disorder characterized by ineffective hematopoiesis. MDS patients are known to manifest overt rheumatic manifestations and have distinct immunological abnormalities but their clinical significance has yet to be elucidated.', 'To investigate the prevalence of autoimmune or rheumatic manifestations in the course of MDS and serological immunological abnormalities which have been detected at presentation and to determine their clinical significance.', 'One hundred and eleven patients diagnosed as having MSD between 2001 and 2004 were identified. Their clinical and serologic features on medical records were retrospectively reviewed.', 'Of 111 patients with MDS, 25 showed 27 autoimmune or rheumatic manifestations. On dividing the cohort into two groups, with and without autoimmune or rheumatic manifestations, the two groups were not statistically different in survival. Serological immunological abnormalities were observed by variable rate, but had no association with compatible clinical manifestations. C3 hypocomplementemia was observed as high as 45.9% and the C3 hypocomplementemic subgroup had more severe cytopenia of red cell and white cell lineages and was dominant in the low-risk International Prognostic Scoring System category.'] Is low C3 levels associated with neutropenia in a proportion of patients with myelodysplastic syndrome : retrospective analysis?