We studied serum amylase and its isoenzymes prospectively in 163 consecutive asymptomatic patients, 149 men and 14 women, infected with HIV and attending an HIV out-patient clinic. Six patients were receiving dideoxyinosine (DDI), a drug known to cause pancreatitis. No patient, however, had clinical signs suggestive of pancreatitis. Serum total amylase was increased in 39 of 163 patients (24%), in 11 of whom (28%), this was due to increased pancreatic (P) isoamylase alone, in 17 (42%) it was due to salivary (S) type alone and in six (17%) it was due to increase of both P and S fractions. In five patients (13%), macroamylase was detected. Pancreatic amylase was elevated in four of the six patients on DDI. The remaining two had macroamylase. Our results show that asymptomatic hyperamylasaemia is a common finding in HIV patients and that it appears to be heterogenous, i.e. elevation may be due to increase in P or S, both enzyme fractions or macroamylase. The high incidence of macroamylasaemia in HIV patients was an unexpected finding.

*Amylases/BLOOD *Enzyme Tests *HIV Infections/DIAGNOSIS *Isoenzymes/BLOOD

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