Detection and typing of paraproteins: comparison of different methods in a routine diagnostic laboratory.

In this paper we review four methods: Protein electrophoresis (PE), immunoelectrophoresis (IEP), immunofixation electrophoresis (IFE) and a nephelometric kappa:lambda ratio method for the ability, first, to detect, and second, to isotype paraproteins in urine and serum. IFE was the most sensitive assay both in the detection of paraproteins and the most accurate in their typing. The nephelometric kappa:lambda ratio was associated with false-positive and false-negative results and cannot be considered suitable for routine diagnostic use. Although IFE was the most sensitive assay it was not without problems. Dilution of the serum to produce a concentration suitable for IFE is critical, and the assay is demanding in operator skill and time. The extra paraproteins identified by IFE are generally of low concentration and with the exception of certain well-defined clinical situations are probably not of great importance in patient management. In the case of diseases where the demonstration of a small amount of paraprotein is important, such as amyloidosis, then IFE should be performed in case other techniques fail to demonstrate a paraprotein. Otherwise, IFE is best reserved for paraproteins detected by PE which cannot be typed by IEP. A schema for the management of paraprotein identification for use in a routine diagnostic laboratory is presented.

Australian hemophiliac recipients of voluntary donor blood products longitudinally evaluated for AIDS. A clinical and laboratory study, 1983-1986.

One hundred and sixty-one Australian patients with hereditary bleeding disorders comprising hemophilia A (120), hemophilia B (18), von Willebrand's disease (16), and seven symptomatic female hemophilia A or B carriers were screened for clinical and serological evidence of exposure to HTLV-III/LAV/ARV/HIV infection. During the previous five years (1979-1984) they had been treated almost exclusively with blood products derived from Australian voluntary donors. The prevalence of HTLV-III antibodies in 1985 was 45%, with the highest frequency being in those with severe hemophilia A (78%) and the lowest in patients with hemophilia B (6%). Antibody positivity correlated with a reduced absolute T helper (T4) cell numbers and/or an inverted T4:T8 ratio. Lymphadenopathy was detected in 23 subjects but only 13 had an abnormal T cell ratio. Comparison of seropositivity and T4:T8 ratios in 32 patients studied in 1983 and again in 1985 suggested that T4 cell deficiency reflected HTLV-III exposure rather than being a predisposing factor for infection with the virus. Individual patients showed considerable fluctuation in T cell subsets over a 12 month period of follow-up, but as a population there was a slight trend with time towards diminishing T4:T8 ratio only in the antibody positive hemophilia A patients of mild to moderate severity. Three (2%) of the 161 patients screened to date have developed confirmed AIDS with fatal outcome.(ABSTRACT TRUNCATED AT 250 WORDS)