Functional activity of peripheral mononuclear cells in cystic fibrosis: antibodies and plaque formation.

Chronic pulmonary infection is known to constitute a major complication of cystic fibrosis (CF). In order to determine whether a defect of antibody formation is associated with this clinical finding, we have investigated antibody production on the cellular level by using a haemolytic plaque forming cell (PFC) assay. The ability of peripheral mononuclear cells (MNC) derived from patients with CF to form PFC upon stimulation by pokeweed mitogen was significantly decreased as compared to healthy control individuals (P less than 0 . 01). Levels of serum immunoglobulins of the G, A, and M classes and of sheep red blood cell agglutinating antibodies were estimated as well, but no correlation was obtained between these parameters and the number of PFC in patients with CF.