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Monocytes of patients congenitally deficient in plasma factor XIII lack factor XIII subunit a antigen and
1Department of Clinical Chemistry, University School of Medicine, Debrecen, Hungary.
Abstract:
Monocytes isolated from patients with severe deficiency in plasma Factor XIII of blood coagulation (FXIII) were tested for FXIII antigen and transglutaminase activity. By immunoperoxidase method the patients' monocytes, in contrast to normal controls, showed no reaction with a monospecific antibody against FXIII subunit a. This result was confirmed by immunoblotting technique, as well. In addition, tissue macrophages tested in one of the patients were also exempt of FXIII subunit a antigen. The transglutaminase activity in FXIII deficient monocytes was below the limit of the detection of the dansylcadaverine incorporation assay. The results suggest that FXIII subunit a of monocytes/macrophages and its plasma and platelet counterparts are closely related or identical proteins and demonstrate that the transglutaminase activity in monocytes is of FXIII origin and tissue transglutaminase is present, if at all, only in insignificant amount.
Insights
Patients with severe Factor XIII (FXIII) deficiency lack FXIII antigen in monocytes and macrophages. This indicates FXIII is the primary source of transglutaminase activity in these immune cells.
Area of Science:
- Hematology
- Immunology
- Biochemistry
Background:
- Factor XIII (FXIII) is crucial for blood coagulation.
- The presence and function of FXIII in monocytes/macrophages are not well understood.
Purpose of the Study:
- To investigate the presence of FXIII antigen and transglutaminase activity in monocytes from patients with severe FXIII deficiency.
- To determine the origin of transglutaminase activity in monocytes.
Main Methods:
- Isolation of monocytes from FXIII-deficient patients and normal controls.
- Immunoperoxidase staining and immunoblotting to detect FXIII subunit a.
- Dansylcadaverine incorporation assay to measure transglutaminase activity.
Main Results:
- Monocytes from FXIII-deficient patients lacked FXIII subunit a antigen.
- Tissue macrophages in one patient also lacked FXIII subunit a.
- Transglutaminase activity in deficient monocytes was undetectable.
Conclusions:
- FXIII subunit a in monocytes/macrophages is closely related or identical to plasma and platelet FXIII.
- Monocyte transglutaminase activity originates from FXIII.
- Tissue transglutaminase is present in insignificant amounts, if at all, in monocytes.