BONE-MARROW PATHOLOGY IN RELAPSING POLYCHONDRITIS - HIGH-FREQUENCY OFMYELODYSPLASTIC SYNDROMES

Haemopathologic changes were studied in 19 patients (13 male, six fema le, age 33-85 years, mean 56 years) with relapsing polychondritis (RP) . Anaemia was found in eight, thrombocytopenia in two and splenomegaly in three patients. A total of 17 bone marrow biopsies were obtained f rom seven individuals. Bone marrow evaluation revealed myelodysplastic syndromes (MDS) with marked trilineage hyperplasia and dysplasia in t hree cases. Since an excess of myeloblasts or an increase of CD34 posi tive progenitor cells was not seen, the disorders were designated as ' refractory anaemia' or with regard to the dysplastic megakaryopoiesis 'MDS, unclassifiable'. Two of the three patients died after 10 and 55 months of follow-up due to infectious complications. In a further pati ent, bone marrow analysis repeatedly showed an unexplained granulopoie tic hyperplasia, which, however, was not dysplastic enough to allow a diagnosis of MDS. The remaining patients had clearly reactive changes. Our findings support the notion that RP is a heterogenous disorder an d suggest that RP may at times represent a paraneoplastic phenomenon o f an underlying MDS. Since HLA typing revealed a significantly increas ed frequency of the antigen DR4 (10/17 patients positive=59%), we hypo thesize that immunological imbalances due to the MDS in conjunction wi th a specific immunogenetic background may play key roles in the patho genesis of RP in these patients.