Effects of age, gender, duration of drug use and infection with viral hepatitis B and C on lymphocyte subsets in a population of HIV-negative injecting drug users in Italy.

Abstract

A series of 716 HIV-negative IDUs entering a large drug treatment centre in central Italy was studied to evaluate the pattern of T-lymphocyte subsets among IDUs and to determine the effects of individual variables such as age, gender, duration of drug use and infection with viral hepatitis B and C. To this end, white cell count, total lymphocyte count and absolute number of lymphocyte subsets (i.e. CD3+, CD4+ and CD8+), HBV markers and HCV serology, were determined. For each individual, information on age, gender and duration of drug use was collected. To evaluate the association between level of lymphocyte subsets and phases of HBV infection, participants were stratified into three groups: (A) negative for all markers; (B) HBsAg-positive, with or without HBeAg, and HBsAb-negative; and (C) HBsAg and HBeAg-negative, positive for any other serological marker. The median absolute number of CD3+, CD4+ and CD8+ was 1909, 1080 and 770 cells/mm3, respectively, and did not vary across age bands. The CD8+ count was higher in males than in females. There was a tendency for CD3+ lymphocyte counts (mainly due to CD8+ counts) to be higher in individuals with 6-8 years of drug use compared to those who started injecting 4 years before or less. There was no evidence of increasing counts for a duration of drug use of more than 8 years. With regard to HBV, there was a general tendency for individuals in group "C" to have higher CD3+ and CD8+ counts than those in group "A". Finally, there was no difference in absolute lymphocyte count subsets between HCV-positive and HCV-negative IDUs. In conclusion, demographic and behavioural factors such as long-term heroin use or infection with HCV do not seem to influence the level of lymphocyte subsets among HIV-negative IDUs, nor does the infection with HBV seem to determine dramatic changes in CD4+ counts.