‘Cold’ IgG Autologous Anti-LW

Abstract

In the routine antibody screening of 45,000 blood samples, 10 cases of coldreacting, autologous anti-LW were discovered, using a low-ionic strength-polybrene Auto-Analyzer. Two of these were shown to belong to the IgG, and one to the IgM class. The others were suspected to belong to the IgG class. An immune anti-LW (from a Dpositive, LW-negative patient) was used for comparison with the cold, ‘naturally-occurring’ anti-LW, and further comparisons were made with anti-D. DEAE fractionation shows a much greater heterogeneity for anti-LW than for anti-D, but iso-electrofocusing of the main IgG fraction shows similar iso-electric points: 8.8 and 8.9 for anti-D and anti-LW, respectively. However, the autologous IgG anti-LW showed an iso-electric point of 8.2, representing a different relationship to the bulk of IgG. The ability for immune anti-LW to discriminate between Rh-positive and negative cells was far greater with the low-ionic strength-polybrene Auto-Analyzer than with the bromelin-methyl cellulose method. In manual testing, the DEAE fractions showed such a discriminating ability only with the IgM containing fractions.