Pernicous anaemia, hypogammaglobulinaemia, and altered lymphocyte reactivity. A family study.

A mother and her identical twin daughters were found to have pernicious anaemia and achlorhydria. The twins lacked detectable serum IgA and had low to absent serum IgG. Both girls also demonstrated a marked impairment of antibody response to a variety of antigens. Evidence for lymphocyte sensitization to intrinsic factor was demonstrated in these patients by the increased incorporation of tritiated thymidine into DNA and by the production of migration inhibition factor.