The present invention relates to the ability ofSerum Amyloid P (SAP) protein to suppress thedifferentiation of monocytes into fibrocytes. It alsorelates to the ability of IL-12, laminin-1, crosslinkedIgG and IgG aggregates to suppress thedifferentiation of monocytes into fibrocytes. Methodsand compositions for suppressing differentiation ofmonocytes into fibrocytes using these proteins areprovided. These methods are useful in a variety ofapplications including treatment and prevention offibrosing diseases such as scleroderma and asthma.Finally, the invention includes assays for detectingthe ability of various agents to modulate monocytedifferentiation into fibrocytes and to detect monocytedefects. Such assays may also be used to diagnosescleroderma or other fibrosing diseases.
