Aberrant phagocyte function in Shwachman syndrome.

Polymorphonuclear leucocytes (PMN) of patients with Shwachman syndrome show impaired mobility in vitro. We took this finding a step further by studying chemotaxis and chemiluminescence responses of purified PMN and monocytes (MO) of seven patients with Shwachman syndrome. Chemiluminescence responses of the patients' PMN were significantly increased, and thus impaired mobility may have derived from auto-oxidation of PMN. Chemotaxis of purified PMN was not impaired in a membrane filter, but it did become impaired when PMN were remixed with autologous mononuclear (MN) cells or MO. These cells always increased the migration of PMN. Because the patients' cells were fully capable of increasing the migration of control PMN, the defect most probably involved PMN. This is in harmony with the finding that the patients' purified PMN showed depressed chemotaxis under agarose. This suggests that for detecting impaired chemotaxis of purified PMN the assay conditions were more optimal in the agarose test than in the filter test. Both chemotaxis and chemiluminescence responses of the patients' MO were depressed, and thus, the defects involving PMN and MO are separate.