Cryoglobulinemia and Decreased Monocyte Chemotaxis in Malignant Melanoma

The sera from 13 patients with malignant melanoma were evaluated for immune complexes by cryoprecipitation and the 125I Clq binding assay. Cryoprecipitates were identified in 12/13 patients (92%) and cryoimmunoglobulins in 7/13 patients (54%). Either cryoimmunoglobulin or elevated Clq binding was identified in 8/13 patients (62%). Incubation of normal monocytes with the resuspended cryoimmunoglobulin of 7 melanoma patients produced greater than 50% reduction in the ability of the monocytes to respond to chemotactic stimuli (p < .01). Similar inhibition was seen with cryoimmunoglobulin from erythema multiforme patients, but not with `medium alone, albumin, heat aggregated albumin or heat aggregated-IgG in similar concentrations. No soluble factors produced in vitro could be demonstrated to produce this inhibition. Inhibition of monocyte function by immune complexes may be an important component of impaired host response to malignant melanoma, or alternatively may represent an important mechanism for the accumulation of monocytes at sites of inflammation, analogous to migration inhibition factor.