LAUSR

Dear Editors, Lead poisoning causes devastating problem on human, such as toxicity of liver, kidney, reproductive system, and nervous system.1 Basophilic stripping cells are the significant sign of lead poisoning. Erythrocytes with basophilic stippling will be seen under microscope through the peripheral blood or bone marrow smears. A 2yearold Tibetan boy presented with poor appetite and vomiting for 3 days. After admission, he developed a convulsion, characterized with loss of consciousness, eyes staring, froth at the mouth and limb stiffness. Routine peripheral blood tests showed microcytic hypochromic anemia (hemoglobin, 73 g/L; red blood cell, 3.13 × 1012/L; hematocrit, 21.8%; mean corpuscular volume, 69.8 fL; mean corpuscular hemoglobin, 23.3 pg; mean corpuscular hemoglobin concentration, 318 g/L; reticulocyte percentage, 4.5%; and reticulocyte count, 0.15 × 1012/L). The pathogenesis of anemia was not found according to serum iron test, hemoglobin electrophoresis, G6PD activity detection, etc. Peripheral blood smears found many basophilic stippling erythrocytes (original magnification ×100, WrightGiemsa stain, Figure 1). Bone marrow smears also found extensive erythrocytes and nucleated erythrocytes with basophilic stippling (original magnification ×100, WrightGiemsa stain, Figure 2), and myeloid/erythroid(M/E) ratio was 0.84:1. LDH was 420 U/L. The blood lead level markedly increased to 965 μg/L (permissible range: <100 μg/L), and the results of other heavy metals were in the normal limits (blood cadmium, 0.13 μg/L; blood chromium, 6.5 μg/L; blood nickel, 7.7 μg/L; blood manganese, 13.0 μg/L; and blood thallium, 0.08 μg/L). So he was diagnosed with severe lead poisoning. The blood lead level of his parents also increased to 379.2 and 541.3 μg/L, respectively, and peripheral blood smears also found many basophilic stippling cells. The boy had chelation treatment (dimercaptosuccinic acid 600 mg twice a day) for 14 days, and the blood lead level decreased to 384.2 μg/L. His parents also received the chelation treatment. They were discharged with a better condition three weeks later. Lead is a toxic heavy metal known to cause extensive environmental pollution due to its environmental persistence and transportability. It can enter human body through food, soil, water, air, etc. The symptoms of lead poisoning are often nonspecific and include headache, abdominal pain, anorexia, and constipation.1 In hematopoietic system, lead poisoning can reduce hemoglobin synthesis and decrease RBC life span by interfering with enzymatic steps in the heme synthesis pathway.2 Basophilic stippling cells are often observed in patients with severe lead poisoning.3 In contrast to fine basophilic stippling in thalassemia, basophilic stippling is typically coarse in lead poisoning as a result of precipitation of RNA secondary to pyrimidine59nucleotidase inhibition.4 Although coarse basophilic stippling erythrocytes is also reported in pyrimidine59nucleotidase deficiency and arsenic poisoning, it can provide an underlying clue to the diagnosis of lead poisoning. Because the symptoms of lead poisoning are often nonspecific and multisystem disorders, lead poisoning may be mistaken for other clinical conditions such as porphyrias. The porphyrias are a group of metabolic disorders caused by abnormal functioning of heme biosynthesis enzymes and characterized by the excessive accumulation and excretion of porphyrins and their precursors.5 Porphyrias are rare inherited diseases and confirmed by the detection of hematoporphyrinrelated genes including ALAS2, ALAD, HMBS, UROS, UROD, and CPOX. The family members had no the specific clinical presentation of porphyrias such as skin photosensitivity, neurovisceral attacks, and dark urine, and the hematoporphyrinrelated genes showed no abnormalities, so we did not consider the porphyrias in this family. Further history revealed that all family members had been taking one of the Tibetan medicines from a local temple for a long time, so the Tibetan medicines from the local temple are the factors which cause them lead poisoning. In Tibetan, west of China, traditional Tibetan medicine (TTM) has been widely used by Tibetan people for thousands of years, and many TTMs have been proven to be effective in the prevention and treatment of many diseases, such as cancer,6 Alzheimer disease,7 and liver disease.8 Because of