Increased porphobilinogen deaminase activity in patients with malignant lymphoproliferative diseases. A helpful diagnostic test.

Patients with malignant lymphoproliferative diseases, ie, chronic lymphocytic leukemia and lymphoma, were found to have higher porphobilinogen deaminase (PBGD) activity in their peripheral lymphocytes than normal control subjects, patients with other malignant neoplasms, and patients with various infectious diseases. The specificity and sensitivity of the test were 99% and 87%, respectively. The sensitivity of the test was 100% in patients with chronic lymphocytic leukemia and 82% in patients with lymphoma. The diagnostic value of PBGD determinations was shown in a prospective study of a group of patients evaluated because of fever of unknown origin, anemia, or other constitutional symptoms with or without lymphadenopathy or a mediastinal mass. The positive and negative predictive values in these patients were 91% and 100%, respectively. Nearly all patients who were in remission had normal enzyme activity. Lymphocyte PBGD determinations also may be of value in determining when to terminate or reinitiate drug treatment.