Bone marrow hyaluronan and reticulin in patients with malignant disorders.

Myelofibrosis is commonly seen in patients with chronic myeloproliferative diseases and sometimes in myelodysplastic syndrome, acute leukaemia and lymphoproliferative diseases. The fibrotic process is evaluated by grading the amount of collagen deposited in the bone marrow interstitium. The established method to evaluate bone marrow fibrosis is staining for reticulin to visualise the collagen fibres. However, the extra cellular matrix does not only contain collagens but also other components, e.g. glycosaminoglycans of which hyaluronan is the most abundant. Hyaluronan is important for structural and cellular functions. Earlier studies have shown that there is a positive correlation between hyaluronan and reticulin staining in healthy volunteers and in patients with de novo acute myeloid leukaemia. In this study bone marrow biopsies from 43 patients with a malignant disease involving the bone marrow were compared with 18 patients with a malignant disease not involving the bone marrow. The intensity of hyaluronan grading was significantly higher in the patients with disease involving the bone marrow compared to the healthy controls but not compared to the patients without disease involving the bone marrow. The staining intensity of reticulin in the bone marrow was significantly higher in the patients with disease involving the bone marrow, compared to those without disease involving the bone marrow and to the controls. In all patients and the controls there was a correlation between hyaluronan and reticulin.