Susceptibility to leprosy and serum atypical pseudocholinesterase.

The pseudocholinesterase levels and the nature of the enzyme as shown by the dibucaine number (D.N.) were estimated in 720 controls and 420 lepromatous leprosy patients, and 301 tuberculoid leprosy patients. There was no statistical difference in the esterase levels between leprosy patients and normal controls. But the distribution of D.N. was significantly different in the leprosy patients compared to the normal population studied. The D.N. below 40 indicates the samples with the atypical pseudocholinesterase--the presence of which is genetically determined. The distribution of samples with D.N. below 40 was significantly higher in the lepromatous leprosy patients compared to the normal population or tuberculoid leprosy patients. It is proposed that since there is a greater incidence of the atypical enzyme in lepromatous leprosy cases, the presence of this enzyme or the deficiency of the typical enzyme may make a person more susceptible to leprosy.