Serum B2 microglobulin (B2M) in CAPD

Twenty-six chronic uremic pts (8F and 18M, mean age 64 yrs) on CAPD for 15 months on the average, were studied as regards the levels of B2M measured by radioimmunoassay in fasting serum samples. Considering residual renal function, 2 pts groups were identified: 11 pts with a diuresis greater than or equal to 500 cc/day and 15 pts with a diuresis less than 500 cc/day. Serum B2M was significantly decreased in the first group (24.8 +/- 8.1 vs 34.7 +/- 7.1 mg/l; p less than 0.02). Considering the incidence of peritonitis episodes, 12 pts without and 14 pts with one or more peritonitis episodes were noted. The group with no peritonitis showed significantly decreased serum B2M values (25.1 +/- 7.6 vs 35.03 +/- 4.8 mg/l; p less than 0.005). No relationship was found as regards primary renal diseases, sex and age of pts. We conclude that residual renal function and peritonitis episodes modify serum B2M levels in CAPD. The long term follow up of pts could be of interest for better defining the role of these factors as regards the incidence of pathologic lesions associated with B2M deposition.