Heterogeneity of IgM/IgG cryocomplexes: immunological-clinical correlation.

A detailed study has been made of the mixed cryoglobulins (MCs) occurring in four patients with different disease states. These included (1) macroglobulinemia of Waldenström with an IgM(K)/IgG cryocomplex containing Clq, free DNA, rheumatoid factor, anti-ssDNA and VDRL activity; (2) Peetom-Meltzer syndrome with an IgM(K)/IgG cryocomplex containing free DNA, Clq, Cls, fibrinogen, alpha2-macroglobulin and beta-lipoprotein; (3) rheumatoid arthritis with an IgM(K)/IgG cryocomplex containing rheumatoid factor, free DNA and anti-ssDNA activity; and (4) angioimmunoblastic lymphadenopathy with an IgM(K)/IgG cryocomplex containing rheumatoid factor, free DNA and anti-I cold agglutinin activity. All of these patients exhibited multisystem involvement with evidence of vascular injury. A review of the MCs found in various clinical states, reveals that whereas in systemic lupus erythematosus MCs almost invariably possess antinuclear factor activity and contain DNA as well as some components of complement, in Peetom-Meltzer syndrome MCs do not have these characteristics, but invariably have strong rheumatoid factor activity, usually absent in MCs from systemic lupus erythematosus. MCs in lymphoproliferative disorders have strong rheumatoid factor activity but not ANF activity. In infectious diseases, MCs usually exhibit strong rheumatoid factor, VDRL and cold agglutinin activity, and co-precipitate with alpha2-macroglobulin. While there is some overlap in the characteristics of MCs from various clinical diseases, the above mentioned differences are probably of some biological importance and require further investigation.