Monoclonal IgM cryoglobulinemia associated with gamma-3 heavy chain disease: immunochemical and biochemical studies

Gamma-heavy chain disease: review of 23 cases

We report the cases of 23 patients with gamma-heavy chain disease seen at our institution (8 patients previously reported, 15 new patients). There were 15 women and 8 men; the median age at diagnosis was 68 years (range, 42-87 yr). Sixteen patients had an associated lymphoplasma cell proliferative disorder, 3 had a lymphoplasma cell proliferative disorder and an autoimmune disorder, another 3 had an autoimmune disorder only, and 1 had no underlying disease. The lymphoplasma cell proliferative disorder was disseminated in 10 patients and localized in 6. Patients with localized lymphoplasma cell proliferative disorder included 3 with plasmacytoma (1 tongue, 1 submandibular area, and 1 thyroid), 2 with lymphoplasma cell proliferative disorder involving the bone marrow only, and 1 with amyloid of the skin. At the time of diagnosis, lymphadenopathy was present in 8 patients, splenomegaly in 7, and hepatomegaly in 1. A monoclonal spike on serum protein electrophoresis was documented in 19 patients. gamma-Heavy chain was documented by immunofixation in the serum of all patients; 2 had an additional immunoglobulin M-lambda. gamma-Heavy chain was present in the urine in 19 of 22 patients. Sixteen patients were treated for lymphoplasma cell proliferative disorder or autoimmune disorder (14 with chemotherapy, 1 splenectomy, and 1 thyroidectomy followed by radiation therapy). For 5 patients, treatment was not felt to be necessary; 2 patients were thought to be too sick for treatment. Of the 16 patients treated, 6 had a complete clinical response (in 2, gamma-heavy chain disappeared; in 2, gamma-heavy chain persisted; and for 2, no serologic follow-up was available); in 10 patients, clinical disease persisted (in 3, gamma-heavy chain disappeared; in 6, it persisted; and for 1, no serologic follow-up was available). Of 7 patients not treated, 2 died within 5 months; 1 died after 15 months; 2 had no clinical disease at latest follow-up, although gamma-heavy chain persisted; and 2 had no change in clinical and serologic status. The median duration of follow-up was 33 months (range, 1-261 mo). Median survival was 7.4 years.

Existence of disulfide-bonded IgM-IgA, IgM-IgG and IgM-IgG fragment complexes in one patient

The existence of disulfide-bonded immunoglobulin (Ig) complexes of IgM-IgA, IgM-IgG, and IgM-IgG, in addition to a monoclonal IgM (kappa) paraprotein, free kappa chains and fragments of IgG (FIgG), were found in the plasma of a multiple gammopathy patient. This is the first report on the interclass disulfide-bonded Ig complexes. Upon exposure to a dissociating buffer containing 6 M urea, 0.1 M Tris-HCl, pH 8.0, a small portion of the IgM-IgA complexes and most of the IgM-IgG as well as the IgM-FIgG complexes dissociated, but the majority of the IgM-IgA and small amounts of other complexes remained intact. These intact complexes were not the result of antigen-antibody reactions and were apparently held together by disulfide bonds which could be broken into monomeric Ig basic units (H-L)2 and smaller components by mild reduction and alkylation.