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[IP] Diabetics may be more susceptible to flu

 NEW YORK, Aug 05 - Diabetics may be particularly susceptible to some
 strains of the flu, according to a study in the August issue of the Journal of

 People with diabetes tend to get sicker, are more likely to develop pneumonia,
 and run a higher risk of dying once they are infected with the influenza virus,
 previous studies have shown. 

 To determine whether having diabetes increases a person's odds of getting
 infected to begin with, the study's authors ran a number of tests on healthy 
 diabetic mice. 

 The authors first inoculated the mice with a common strain of influenza virus,
 waited a day, and then checked the extent to which the virus had proliferated 
 the animals' lungs. After 24 hours, the diabetic mice had 10 times as much 
virus in
 their lungs as the healthy mice, "indicating a deficiency in some aspect of 
 immunity,'' report the authors, a team of researchers headed by Dr. Patrick C.
 Reading of the University of Melbourne in Australia. 

 Viral levels were highest in the lungs of the diabetic mice that had the 
highest levels of glucose in their blood at the time they were inoculated, 
Reading and colleagues found. 

 But when the researchers gave the diabetic mice insulin - to lower their blood
 glucose levels - then inoculated them with the virus, waited 3 days and
 measured viral proliferation, they found the animals had no more virus in their
 lungs than healthy mice. 

The researchers found similar results when they inoculated healthy and diabetic
mice with a second strain of influenza virus. Once again, the diabetic animals 
had higher levels of the virus in their lungs than the healthy mice. 

But Reading and colleagues found no difference in extent of viral proliferation 
in the lungs of healthy and diabetic mice when they inoculated the animals with 
a third strain of the virus. Unlike the other two strains, this strain is 
resistant to a class of immune system proteins called collectins, Reading and 
colleagues note. 

 This finding is significant, because previous research suggests that glucose 
can bind to and interfere with the activity of a collectin called lung 
surfactant protein D (SP-D), the researchers write. Consequently, diabetics may 
be more susceptible to SP-D responsive strains of the influenza virus because 
the high glucose levels in their blood inactivate SP-D. 

 "The results of the present study suggest that susceptibility to influenza 
virus infection itself may also be higher for diabetic than for nondiabetic 
individuals, due to compromise of their collectin-mediated host defenses,'' 
Reading and colleagues conclude. 

 SOURCE: Journal of Virology 1998;72:6884-6887. 

Insulin-Pumpers website http://www.bizsystems.com/Diabetes/