When the amount of anti-A/B antibodies in samples of 34 CVID patients, diagnosed according to the criteria established by the IUIS expert committee (5), was determined by the Diamed-ID Micro Typing System using the ID-Card 50520 (NaCl) to measure IgM-isoagglutinins, no difference could be found between CVID patients and healthy individuals (Figure 1A, left panel). The gene discussed is CD40LG; the disease is common variable immunodeficiency.