David G. Nathan

Chronic granulomatous disease is an X-linked defect in the killing of certain bacteria by peripheral blood granulocytes and may be detected with the nitroblue tetrazolium (NBT) test. The rate of reduction of NBT by normal leukocytes is stimulated by phagocytosis. It also depends on cell number, pH and temperature. Granulocytes of affected male patients failed to reduce NBT to blue formazan during phagocytosis whereas leukocytes of carrier females, usually asymptomatic, demonstrated intermediate dye reduction. A 17year-old girl, who had lifelong recurrent suppurative infections, was identified as having chronic granulomatous disease by the NBT test. Her leukocytes and those of affected males had absent dye reduction, low values for oxygen consumption and diminished NADH oxidase activities during phagocytosis. Her parents' leukocytes had normal dye reduction rather than the intermediate values noted in mothers of affected males. Thus, the disease may also be transmitted as an autosomal recessive trait.

BACKGROUND: The prognosis of patients with homozygous beta-thalassemia (thalassemia major) has been improved by transfusion and iron-chelation therapy. We analyzed outcome and prognostic factors among patients receiving transfusions and chelation therapy who had reached the age at which iron-induced cardiac disease, the most common cause of death, usually occurs. METHODS: Using the duration of life without the need for either inotropic or antiarrhythmic drugs as a measure of survival without cardiac disease, we studied 97 patients born before 1976 who were treated with regular transfusions and chelation therapy. We used Cox proportional-hazards analysis to assess the effect of prognostic factors and life-table analysis to estimate freedom from cardiac disease over time. RESULTS: Of the 97 patients, 59 (61 percent) had no cardiac disease; 36 (37 percent) had cardiac disease, and 18 of them had died. Univariate analysis demonstrated that factors affecting cardiac disease-free survival were age at the start of chelation therapy (P < 0.001), the natural log of the serum ferritin concentration before chelation therapy began (P = 0.01), the mean ferritin concentration (P < 0.001), and the proportion of ferritin measurements exceeding 2500 ng per milliliter (P < 0.001). With stepwise Cox modeling, only the proportion of ferritin measurements exceeding 2500 ng per milliliter affected cardiac disease-free survival (P < 0.001). Patients in whom less than 33 percent of the serum ferritin values exceeded 2500 ng per milliliter had estimated rates of survival without cardiac disease of 100 percent after 10 years of chelation therapy and 91 percent after 15 years. CONCLUSIONS: The prognosis for survival without cardiac disease is excellent for patients with thalassemia major who receive regular transfusions and whose serum ferritin concentrations remain below 2500 ng per milliliter with chelation therapy.

Hydroxyurea, a widely used cytotoxic/cytostatic agent that does not influence methylation of DNA bases, increases fetal hemoglobin production in anemic monkeys. To determine its effect in sickle cell anemia, we treated two patients with a total of four, 5-d courses (50 mg/kg per d, divided into three oral doses). With each course, fetal reticulocytes increased within 48-72 h, peaked in 7-11 d, and fell by 18-21 d. In patient I, fetal reticulocytes increased from 16.0 +/- 2.0% to peaks of 37.7 +/- 1.2, 40.0 +/- 2.0, and 32.0 +/- 1.4% in three successive courses. In patient II the increase was from 8.7 +/- 1.2 to 50.0 +/- 2.0%. Fetal hemoglobin increased from 7.9 to 12.3% in patient I and from 5.3 to 7.4% in patient II. Hemoglobin of patient I increased from 9.0 to 10.5 g/dl and in patient II from 6.7 to 9.9 g/dl. Additional single-day courses of hydroxyurea every 7-20 d maintained the fetal hemoglobin of patient I t 10.8-14.4%, and the total hemoglobin at 8.7-10.8 g/dl for an additional 60 d. The lowest absolute granulocyte count was 1,600/mm3; the lowest platelet count was 390,000/mm3. The amount of fetal hemoglobin per erythroid burst colony-forming unit (BFU-E)-derived colony cell was unchanged, but the number of cells per BFU-E-derived colony increased. Although examination of DNA synthesis in erythroid marrow cells in vitro revealed no decreased methylcytidine incorporation, Eco RI + Hpa II digestion of DNA revealed that hypomethylation of gamma-genes had taken place in vivo after treatment. This observation suggests that hydroxyurea is a potentially useful agent for the treatment of sickle cell anemia and that demethylation of the gamma-globin genes accompanies increased gamma-globin gene activity.

The intact leukocytes of two children with chronic granulomatous disease fail to reduce nitroblue tetrazolium during phagocytosis. This is due to defective operation of an oxidase of reduced nicotinamide adenine dinucleotide that is insensitive to cyanide and that indirectly stimulates the oxidation of glucose-6-phosphate in leukocytes. Such leukocytes undergo no increase in oxygen consumption or in activity of the hexose monophosphate shunt during phagocytosis, although lactate production is normal. The addition of nitroblue tetrazolium to a leukocyte suspension appears to provide a sensitive diagnostic screening test for this disease.