Abstract: It has been recognized in recent years that some patients with myelodysplastic syndromes (MDS) develop immune-mediated complications (IMC), but little is known about the correlations to MDS-specific disease features. In a retrospective study of 82 MDS patients, we identified 10 (12%) with IMC (group A) and compared them to the remaining 72 cases (group B). Group A consisted of 5 patients with biopsy-verified skin vasculitis and 1 case each with temporal arteritis/polymyalgia rheumatica, necrotising panniculitis, Hashimoto's thyroiditis, autoimmune thrombocytopenia, and Sweet's syndrome. Survival times, sex ratio and distribution of MDS subtypes were similar in the two groups. The patients in group A were younger than those in group B (median 66 vs. 76 years, p<0.01). Four patients (40%) in group A had a history of previous genotoxic therapy for malignant disorders. The bone marrow karyotype was evaluated in 62 patients. Clonal chromosomal abnormalities were found more frequently in Group A than in group B (8/9 vs. 26/53, p = 0.03), and complex karyotypes, i.e., three or more aberrations, were also observed to be more common in group A (3/9 vs. 8/53). The results indicate that IMC preferentially develop in patients with secondary MDS, in younger MDS cases, and in patients with cytogenetic abnormalities.