Immunoglobulins in families of myeloma patients

The serum immunoglobulin levels of 200 first-degree relatives and 23 spouses of 32 patients with myelomatosis were compared with those of age- and sex-matched control persons. First-degree relatives of myeloma patients appeared to have higher serum levels of IgG (P less than 0.05), IgA (P less than 0.05), and IgM (P less than 0.01) than their age- and sex-matched controls. The spouses as a group did not differ from their controls in this respect. No statistically significant difference in the incidence of M-components among family members (0.6%) and spouses (4.3%) was found compared with the incidence in the general population (0.9%). Myelomatosis as such appeared to be more frequent than in the general population (P less than 0.05).