Silent antibodies

Over the past years, progress has been made in understanding B cells and antibody recognition functions, particularly in the context of autoimmune diseases. In addition to the existence of "natural antibodies", recent studies suggest the existence of immunoglobulins with no apparent specificity that may acquire polyreactivity following a mild denaturation in inflammatory sites. They are called "silent antibodies". Together with related observations on B cell development, selection and signaling, the recent insights are providing clues into our understanding of autoimmunity.     

Silent endocrine tumors

Some tumors of hormonal organs are clinically active, while others are not. The silent tumors may be discovered by accident or because of effects due to their increase in size. From a simple steady state analysis of hormonal feedback systems follows that hormonal cell multiplication does not significantly influence the systems steady state behaviour (hence the clinical silence). —Exceptions to this rule occur in three situations: when the gain of the system is low; when the growth concerns cells with isolated sensor or reference functions; or because of the growth of autonomous cells. In many biological systems the dangerous situation of clamping to low levels upon sensor cell multiplication has been prevented by lumping, such as the combination of sensor and comparator functions into sensor-comparator cells.