In the course of studying antinuclear antibodies in the rheumatic diseases, a new precipitin reaction (provisionally referred to as PM-1) was observed between calf thymus nuclear extract and polymyositis sera. Objectives of this study were to further define the immunologic nature of this reaction and to determine its specificity for polymyositis. Immunodiffusion studies using calf thymus nuclea...

Antibodies to a variety of tissues and tissue extracts have been demonstrated in the serum of older persons (Goudie, Anderson, and Gray, 1959; Irvine, 1965). The occurrence of antinuclear factors (ANF) in the ageing has been pointed out by Beck (1963) and Litwin and Singer (1965). These studies, however, have dealt with populations composed of both well and sick individuals and have not related...

Pitfalls in the method for demonstrating antinuclear antibodies (ANA) by the indirect immunofluorescence technique are described and the use of international standard preparations outlined. Determination of the optimal border dilution dividing positive from negative results is discussed. Each laboratory is a unique setting; it must define its own method, which should rarely be changed. One shou...