Short communicationClassical and lectin complement pathway activity in polyneuropathy associated with IgM monoclonal gammopathy

- Complement activity does not differ between IgM-PNP and controls.
- Complement activity does not predict disease progression in IgM-PNP.
- MBL2 genotype might protect against IgM-PNP.

Polyneuropathy associated with IgM monoclonal gammopathy (IgM-PNP) is a slowly progressive, sensorimotor neuropathy. It is assumed that complement activation contributes to IgM-PNP pathogenesis.We investigated whether innate differences in complement activity of the classical and mannose binding lectin (MBL) pathways are associated with IgM-PNP or its severity. We measured complement activity using ELISA and determined MBL serum concentrations and MBL gene polymorphisms in 83 patients and 83 healthy controls.We did not observe differences between IgM-PNP patients and healthy controls nor associations with different disease severities. Differences in innate complement activity are not likely to explain susceptibility to or severity of IgM-PNP.

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