Does CD4 Cell Count Influence Liver Fibrosis in HIV/HCV Coinfected People?

Neither current nor lowest-ever CD4 T-cell levels were associated with hepatitis C virus (HCV) viral load or severity of liver fibrosis in HIV positive people after adjusting for other factors, according to a Spanish study presented at the recent 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2010) in Boston.

Past research has shown that people with HIV/HCV coinfection tend to experience more rapid and aggressive liver disease progression and respond less well to interferon-based therapy than patients with hepatitis C alone. But studies have produced conflicting data for coinfected individuals on effective antiretroviral therapy with well-preserved immune function, and the influence of CD4 cell count remains unclear.

J. Collazos from Hospital de Galdacano and colleagues evaluated the effect of immune status on HCV viral load and liver fibrosis among a cohort of HIV/HCV coinfected patients in Spain.

Participants were categorized on the basis of current CD4 cell count as having poor (<200 cells/mm3; n=117) or good (>500 cells/mm3; n=441) immune function. Various HCV-related and fibrosis-related parameters were compared between the 2 groups. Fibrosis was evaluated using transient elastometry (FibroScan) and other non-invasive measures.

Results

• In a univariate analysis looking at the effect of single variables, a number of factors -- including fibrosis parameters -- were significantly associated with immune status.
• However, in a multivariate analysis controlling for potentially confounding factors, current immune status and nadir (lowest-ever) CD4 cell count were not significantly associated with HCV viral load.
• Current and nadir CD4 count also were not significant predictors of liver fibrosis at the time of evaluation or fibrosis progression over time.
• The following factors were independently associated with significant fibrosis, advanced fibrosis, or cirrhosis, as compared with absent or minimal fibrosis:
• Heavy alcohol use: odds ratio (OR) 3.38 for significant fibrosis, 9.52 for advanced fibrosis, and 25.0 -- or more than 25 times greater risk -- for cirrhosis);
• Hepatitis B surface antigen (HBsAg) positive, indicating HIV/HCV/HBV triple infection: OR 7.81, 47.62, and 33.33, respectively;
• Lower platelet count (thrombocytopenia): OR 0.99, 0.99, and 0.99, respectively;
• CDC HIV/AIDS clinical stage: OR 0.25, 0.40, and 0.14, respectively, indicating reduced risk for lower stages.
• Immunological status was not significantly associate with any fibrosis stage in the multivariate model.

Based on these results, the researchers concluded, "The current or past immunological status of HIV/HCV coinfected patients does not seem to have any significant influence on HCV viral load or on the development of liver fibrosis when adjusting for important covariates."

Further investigation is needed to explain the disparity between these findings and those of prior studies showing that both current and lowest-ever CD4 count are associated with more rapid fibrosis progression.

Investigator affiliations: Hosp de Galdacano, Galdacano, Spain; Hosp Univ. Centr Asturias, Oviedo Univ. Medical School, Oviedo, Spain.

10/1/10

Reference
J Collazos, JA Carton, and V Asensi. Immunological Status Does not Influence Hepatitis C Virus or Liver Fibrosis in Human Immunodeficiency Virus-Hepatitis C Virus-Coinfected Patients. 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2010). Boston, September 12-15, 2010. Abstract V-1793.