Accuracy of serum IgM and IgA monoclonal protein measurements by densitometry.

We previously reported that proper dilution of sera that contain IgG monoclonal proteins (M-proteins) is necessary for accurate quantitation of serum albumin and M-protein concentrations separated by serum protein electrophoresis (SPE) using the Beckman PARAGON agarose electrophoresis system. We now report the significance of pre-electrophoretic serum dilution for M-protein quantitation of sera from patients with IgA and IgM monoclonal gammopathy. We measured M-proteins by SPE in 82 serum samples from 29 patients with IgA and 72 samples from 23 patients with IgM monodonal gammopathy. The serum M-protein concentrations (mean +/- SD) at 1:5, 1:10, and 1:20 dilutions (v/v) for all samples of both types were 49.7 +/- 12.9, 49.1 +/- 13.1, and 47.8 +/- 13.0 g/L, respectively. Thirty-two (20.8%) of 154 sera showed varying degrees of increase in M-protein concentrations with serum dilutions higher than 1:5; only 8 (5.2%) showed an increase 3 SDs. By SPE, the M-protein concentration (mean +/- SD) of these 8 sera at 1:5, 1:10, and 1:20 dilutions were 52.6 +/- 7.8, 57.1 +/- 7.2, and 57.6 +/- 7.1 g/L, respectively; the albumin concentrations (mean +/- SD) were 41.4 +/- 4.4, 37.9 +/- 3.8, and 37.1 +/- 2.9 g/L, respectively. The corresponding albumin concentration (mean +/- SD) was 36.8 +/- 3.7 g/L, assayed by the bromcresol green dye-binding method. These 8 samples were obtained from 3 patients, 2 with IgM kappa and 1 with IgA lambda monoclonal gammopathy. On the electrophoresis membranes, the M-protein bands of these 8 samples were narrow, thin, and dense; upon scanning, they appeared taller and thinner than the corresponding albumin bands. The samples of this subset contained relatively high concentrations of M-protein and total serum protein. We conclude that a pre-electrophoretic dilution of 1:5 (v/v) is adequate for most sera with IgA or IgM M-proteins. However, 1:10 or 1:20 dilution is occasionally required for a subset of sera with IgA or IgM M-proteins that show an unusually thin, narrow, and dense M-protein band and have high total serum protein content.

Pulmonary granulomatosis associated with insoluble fillers in a heroin addict.

We report a case of acute respiratory distress syndrome (ARDS) and pulmonary granulomatosis after intravenous injection of heroin. This 46-year-old male had a 2-year history of heroin addiction. The recent admission was due to loss of consciousness after intravenous injection of diluted heroin with unknown filler. Initial chest X-ray revealed a picture of ARDS. Blood routine and biochemistry were normal except for leukocytosis. Urine morphine test was positive. The blood and sputum culture yielded no pathogens. After supportive treatment, his condition improved, and the follow-up chest X-ray showed diffuse micronodules in both lung fields. Subsequently, open-lung biopsy of the right upper and lower lobes on the 26th hospital day showed large amounts of foreignbody granulomas distributed over perivascular areas, bronchiolar areas and interstitium. Staining for bacteria, fungi, and mycobacteria was all negative. The morphology of foreign-bodies could be divided into 2 types: 1) periodic acid-Schiff (PAS)-positive, aggregated fine crystals in round form; and 2) PAS-negative, yellow long crystals. The pathological diagnosis of pulmonary granulomatosis was made based on the finding of filler foreign bodies. The nature of these foreign bodies remained undetermined. The case suggests that pulmonary granulomatosis with the radiographic appearance of chronic interstitial pneumonia can occur in patients with a history of heroin use.