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Aberrant phagocyte function in Shwachman syndrome
H Repo1, E Savilahti, M Leirisalo-Repo
1Department of Bacteriology and Immunology, University of Helsinki, Finland.
Abstract:
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.
Insights
Shwachman syndrome patients exhibit abnormal polymorphonuclear leucocyte (PMN) function. Their PMN show increased chemiluminescence and impaired chemotaxis, suggesting separate defects in PMN and monocytes (MO).
Area of Science:
- Immunology
- Hematology
- Genetic Disorders
Background:
- Polymorphonuclear leucocytes (PMN) from Shwachman syndrome patients demonstrate reduced in vitro mobility.
- Understanding the specific cellular defects in Shwachman syndrome is crucial for diagnosis and treatment.
Purpose of the Study:
- To investigate the chemotaxis and chemiluminescence responses of purified PMN and monocytes (MO) in Shwachman syndrome patients.
- To elucidate the cellular basis of impaired immune cell function in Shwachman syndrome.
Main Methods:
- Purified PMN and MO from seven Shwachman syndrome patients were analyzed.
- Chemotaxis assays (membrane filter and agarose) and chemiluminescence assays were performed.
Main Results:
- Patients' PMN exhibited significantly increased chemiluminescence, suggesting auto-oxidation.
- Chemotaxis of purified PMN was impaired under agarose but not membrane filter assays when remixed with autologous mononuclear cells or MO.
- Both chemotaxis and chemiluminescence responses of patients' MO were depressed, indicating distinct defects in PMN and MO.
Conclusions:
- Impaired PMN mobility in Shwachman syndrome may stem from auto-oxidation.
- The agarose assay is more sensitive for detecting impaired PMN chemotaxis than the filter assay.
- Shwachman syndrome involves separate functional defects in both PMN and MO.