The presence of abnormal lysosomes in lymphocytes and neutrophils during chloroquine therapy: a quantitative ultrastructural study.

Lysosomal ultrastructure in circulating lymphocytes and neutrophils from the blood of 22 patients with rheumatoid arthritis or systemic lupus erythematosus undergoing chloroquine therapy has been examined and compared with that of rheumatoid cases receiving alternative forms of treatment and non-rheumatoid controls. The lymphocytes of all 22 patients receiving chloroquine showed a highly significant number of lamellar inclusion bodies (mean 9.3%) compared with only occasional inclusions in six of the 14 rheumatoid and four of the 12 non-rheumatoid controls (means 0.86% and 0.83% respectively). Neutrophils from eight chloroquine-treated patients also showed abnormal granules which were absent from both control groups. These findings confirm our earlier in vitro work which indicated that lymphocytes, compared with neutrophils, had a greater susceptibility to chloroquine action with respect to alterations in lysosomal structure.