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Effects of cryoglobulins and aggregated IGG on in vitro monocyte phagocytosis
Abstract:
Monocyte yeast cell phagocytosis (YCP) was low in presence of cryoglobulins(CG) from 7 of 7 patients with SLE and RA with vasculitis and from 2 of 5 patients with essential cryoglobulinaemia. IgM and C3 were detected only in CG associated with low YCP. Furthermore, low YCP was only found with CG isolated from hypocomplementaemic sera. The results also showed low YCP when heat-aggregated IgG (HAG) greater than or equal to 19S was added to the culture medium. In the presence of HAG or SLE-sera, preopsonized yeast cells could be adequately phagocytosed by monocytes whereas, in parallel cultures, the phagocytosis of untreated yeast cells was low. It is possible that CG and HAG impair YCP in the same way as SLE-sera. The nature of this presumed common mechanism has not been clarified in this limited study. The findings are, however, compatible with the possibility that immune complexes may interfere with the opsonization of the yeast cells, possibly through inactivation of complement components.
Insights
Cryoglobulins (CG) and aggregated IgG impair monocyte yeast cell phagocytosis (YCP), potentially by interfering with complement-mediated opsonization in systemic lupus erythematosus (SLE) and related conditions.
Area of Science:
- Immunology
- Rheumatology
Background:
- Cryoglobulins (CG) are immune complexes found in various autoimmune diseases.
- Monocyte phagocytosis is a critical immune defense mechanism.
- Impaired phagocytosis is linked to disease pathogenesis in conditions like SLE.
Purpose of the Study:
- To investigate the effect of cryoglobulins (CG) on monocyte yeast cell phagocytosis (YCP).
- To explore potential mechanisms underlying impaired phagocytosis in the presence of CG and aggregated IgG.
Main Methods:
- Assessing YCP in monocytes from patients with SLE, RA, and essential cryoglobulinemia.
- Analyzing CG for IgM and C3 presence.
- Evaluating YCP with heat-aggregated IgG (HAG) and SLE sera.
Main Results:
- Low YCP was observed in the presence of CG from SLE and RA patients with vasculitis, and some patients with essential cryoglobulinemia.
- IgM and C3 were detected in CG associated with low YCP and hypocomplementemic sera.
- Heat-aggregated IgG (HAG) also reduced YCP, suggesting a common inhibitory mechanism.
Conclusions:
- Cryoglobulins (CG) and heat-aggregated IgG (HAG) can impair monocyte yeast cell phagocytosis (YCP).
- This impairment may involve interference with complement-mediated opsonization.
- Further research is needed to elucidate the precise mechanism shared by CG, HAG, and SLE sera in affecting phagocytosis.