TYPE-III PROCOLLAGEN N-PEPTIDE CORRELATES WITH BETA-2-MICROGLOBULIN IN MYELOMATOSIS

The serum concentration of the N-terminal peptide of type III procolla gen (PIIINP) was determined in 32 patients with myelomatosis (MM). Fou r subjects were studied at the time of diagnosis and the remaining pat ients at variable intervals from diagnosis. Serum concentration of bet a-2-microglobulin (B2m) was measured in 31 patients, Serial measuremen ts of both substances were performed in 20 patients, Serum PIIINP was increased in MM as compared with healthy control subjects (P < 0.001), Patients with active disease had significantly higher propeptide valu es (median 7.4; range 3.8-11.2) as compared to those with stable disea se (median 4.3; range 2.2-9.6) (P < 0.009). A highly significant corre lation existed between circulating PIIINP and B2m (P < 0.001). It is c oncluded that MM elicits a stromal reaction as reflected by parallel i ncreases in serum PIIINP and serum B2m. In subsets of patients, e.g. t hose with non-secretory myeloma and in patients with smouldering disea se, serum PIIINP may even be superior to B2m as an indicator of diseas e activity.