Objectives: We recovered an IgG1-kappa cryocrystalglobulin in synovial fluid and membrane specimens from a patient with destructive arthropathy. In the present study, we investigated its proinflammatory properties by measuring its effects on TNF-alpha production by normal human monocytes.
Materials and methods: Normal human monocytes isolated by plastic adhesion were cultured in microtiter plates. Adherent monocytes were cultured for 6, 8, and 24 hours with sterile cryocrystalglobulin (150 microg/mL and 2 mg/mL), type I noncrystallised cryoglobulin (same concentrations), monosodium urate (MSU) crystals (2 mg/mL), LPS (10 microg/mL), or medium alone. Supernatant TNF-a concentrations were assayed using an ELISA.
Results: Cryocrystalglobulin had no effect on TNF-alpha production by normal human monocytes. Noncrystallised cryoglobulin increased TNF-alpha levels in supernatants in a time-dependent and concentration-dependent fashion. This increase was significantly less marked than the increases achieved with MSU crystals or LPS.
Conclusion: IgG1kappa cryocrystalglobulin has no effect on TNF-alpha production by normal human monocytes. Fc region changes within the cryocrystalglobulin molecule may explain this finding.