Cyclic nucleotide phosphodiesterases and methyltransferases in purified lymphocytes, monocytes and polymorphonuclear leucocytes from healthy donors and asthmatic patients.

Cyclic nucleotide phosphodiesterase and phospholipid N-methyl-transferase activities were simultaneously measured in purified polymorphonuclear cell-, mononuclear cell-, lymphocyte- and monocyte-homogenates from control subjects, from patients with atopic asthma and from patients with non-atopic asthma. Whereas cyclic AMP and cyclic GMP phosphodiesterase activities were found to be about 10-fold lower in polymorphonuclear than in mononuclear cells, phospholipid N-methyltransferase proved to be rather similar in each cell type from control donors. Cyclic AMP phosphodiesterase and phospholipid N-methyltransferase were significantly decreased in polymorphonuclear cells and monocytes from asthmatic patients compared with the control group while cyclic GMP phosphodiesterase was significantly impaired only in the monocyte subpopulation.