Aplastic anaemia associated with organochlorine pesticide: case reports and review of evidence.

Three patients with aplastic anaemia had a history of substantial previous exposure to organochlorine pesticides. The temporal association between chemical exposure and the onset of first symptoms of anaemia was strongly supportive. Organochlorines have the property of lipid affinity and accumulation in adipose tissue. Objective evidence of clinically important concentrations of tissue pesticide residues may be a useful confirmation of previous exposure. In the patients studied the presence of Lindane (gamma hexachlorocyclohexane) was shown using gas chromatography/mass spectrometry with selective ion monitoring of fragments obtained from one heavily exposed patient, with concentrations about five times greater than a matched control. The presence of clinically important tissue concentrations of pentachlorophenol was also confirmed in a second patient exposed to this agent. The long term safety of organochlorine pesticides remains doubtful as they were introduced before adequate toxicological screening tests had been developed. The central registration of possible haematological adverse reactions, however, forms an important epidemiological method in the study of environmental chemical hazards and should be complied with whenever possible.