By Liz Highleyman

It is well known that HIV positive individuals coinfected with hepatitis B or C can develop advanced liver disease with portal hypertension, or elevated pressure in the portal vein that carries blood between the gastrointestinal tract and the liver. But in other patients, liver disease may be "cryptogenic," or without an identifiable cause.

In the January 11, 200 issue of AIDS, French researchers described a newly identified cause of liver disease -- nodular regenerative hyperplasia -- based on an analysis of 97 consecutive HIV positive individuals with abnormal liver function tests and/or symptomatic portal hypertension of unknown origin who received liver biopsies at a Paris specialty liver disease clinic between 2003 and 2006.

Nodular regenerative hyperplasia is characterized by nodules, or areas of excessive cell growth, throughout the liver, but without septal fibrosis (fibrous tissue between the nodules).

Results

• About 8% of patients had clear or suspected nodular regenerative hyperplasia.

• Among these patients, the median CD4 cell count was about 250 cells/mm3, 5 had undetectable HIV viral load (< 50 copies/mL), and all were on HAART.

• 7 patients had clear liver architecture corresponding to nodular regenerative hyperplasia.

• 1 additional patient had a clinical presentation suggestive of the condition, with sinusoidal dilatation but without overt liver disease.

• 4 patients had bleeding varices, 2 had portal vein thrombosis, and 2 had ascites.

• None of the patients with nodular regenerative hyperplasia died, although 3 were wait-listed for liver transplantation.

Conclusion

"Nodular regenerative hyperplasia appears to be a new cause of portal hypertension in HIV-infected patients," the authors concluded. "This syndrome can be of critical importance as patients can be exposed to the significant complications of portal hypertension and to refractory ascites which may require liver transplantation."

The authors suggested that this potentially fatal condition is probably under-diagnosed in HIV positive patients. They speculated that the condition may be associated with liver toxicity due to antiretroviral therapy. All 8 patients in this analysis had used ddI (didanosine; Videx), which has previously been linked to cryptogenic liver disease. HIV infection itself may also play a role, given that HIV positive individuals are at higher risk for pulmonary hypertension.

Universite Paris-Descartes; Hopital Cochin; Hopital Necker; Hopital Saint Louis; INSERM U. 567, Paris, France.

02/09/07

Reference
V Mallet, P Blanchard, V Vekarre, and others. Nodular regenerative hyperplasia is a new cause of chronic liver disease in HIV-infected patients. AIDS 21(2): 187-192. January 11, 2007.