Absolute Lymphocyte Count: A Probable Substitute Marker for CD4 Count in HIV-Infected Patients in Economically Restrained Countries

Abstract

Objective: CD4 count is the mainstay criteria for initiation of HAART (Highly Active Anti-retroviral Therapy) and assessment of disease progression in HIV patients. CD4 percentage adds additional prognostic information.Our study was aimed to find out if Absolute Lymphocyte Count (ALC) could serve as a substitute marker for CD4 count and percentage. Methods: A total of 455 EDTA blood samples from HIV-infected patients were analyzed for their ALC, CD4 counts and CD4 percentages, over a period of 6 months, from January 2015 to June 2015 in Kasturba Hospital, Manipal. Correlation analysis of ALC with CD4 count and percentage, and receiver operating characteristic (ROC) analysis at CD4  200/μL andCD4  350/μL were conducted as proposed by WHO guidelines. Results: The male to female ratio was 2:1 and age ranged from 11 to 78 years.The median ALC was 1600/μL, median CD4 count was 258.58/μL and the median CD4 percentage was 16.4%. A strong positive correlation (Pearson coefficient, r= 0.741) was obtained between CD4 count and ALC. However, a weak positive correlation (r= 0.276) was seen between ALC and CD4 percentage. Areas under the ROC curve for ALC with CD4 count  200/μL andCD4 count  350/μL were 0.901 and 0.911,respectively, both of which showed an excellent correlation. But area under the ROC curve for ALC and CD4  20% was 0.659, which is poor in accuracy. Also, from the ROC analysis, the ALC cut offs at CD4 count  200/ μL (Sensitivity-83.87%, specificity-81.41%) and CD4 count  350/μL (Sensitivity-80.22%, specificity-86.44%) were  1450/μL and  1650/μL respectively. Conclusion: ALC has a strong correlation with CD4 count and the ALC cut offs corresponding to CD4 counts  200/μL and CD4 count  350/μL were  1450/μL and  1650/μL, respectively. But ALC did not have a good correlation with CD4 percentage. Hence, ALC is a credible alternate marker for CD4 count, but not for CD4 percentage.