Purpose: The effects of a low-antigen-content diet (LAC diet) versus a standard normocaloric diet on the signs and symptoms of mixed cryoglobulinemia (MC) were compared in a crossover randomized study.
Patients and methods: The study consisted of 24 outpatients with MC, and was carried out in a 48-week period. After 18 weeks of either the LAC or the placebo diet, patients returned to a totally unrestricted diet for 12 weeks (washout period) and crossed over to the second half of the study for the other 18 weeks.
Results: After three weeks of the restricted LAC diet, the cryocrit decreased from 3.5 +/- 3.4% (mean +/- SD) to 2.3 +/- 2.0% (p less than 0.01), and the circulating immune complex levels decreased from 48 +/- 30% to 39 +/- 34% (p less than 0.01). At the same time, the purpura score (p less than 0.05), glutamic pyruvic transaminase level (p less than 0.01), and gamma glutamyl transferase level (p less than 0.001) significantly improved. Splenic reticuloendothelial function, measured as the half-life of heat-damaged autologous red cells, decreased from 41 +/- 21 minutes to 21 +/- 10 minutes (p less than 0.005). In contrast, no significant parallel clinical, biochemical, and immunologic changes occurred in the same patients during the placebo (standard normocaloric) diet.
Conclusion: These data show that an LAC diet decreases the amount of circulating immune complexes in MC and can modify certain signs and symptoms of the disease. These effects of the LAC diet may be explained by postulating a functional restoration of the mononuclear phagocytic system.