title: Estimation of the predictive role of plasma viral load on CD4 decline in HIV-1 subtype C-infected subjects in India.
abstract: BACKGROUND
  Plasma viral load has been shown to be a meaningful prognostic marker for disease progression in untreated, HIV-1 subtype B-infected subjects in United States and Western Europe and therefore used as a prognostic marker for disease progression. Because of high expenses of commercially available viral load assays, the role of viral load in disease progression has not been evaluated in HIV-1 subtype C-infected patients in India.
  
  
  METHODS
  We developed an inexpensive real-time reverse transcriptase-polymerase chain reaction assay to quantify viral load in plasma of HIV-1 subtype C-infected subjects from India and used it in a longitudinal analysis of viral load and CD4 cell number in HIV-infected subjects from Calcutta, India.
  
  
  RESULTS
  The real-time reverse transcriptase-polymerase chain reaction assay can quantify plasma viral load with a linear range of detection from 10 to 10 HIV-1 RNA copies per input. Longitudinal analysis of viral load in a cohort of 39 subjects over an average period of approximately 3 years indicates that 1-log increase in HIV-1 RNA level was associated with a decline of 67 CD4 cell count. Furthermore, HIV-1 RNA level between 500 and 50,000 copies per milliliter would predict a 12.9% decrease in CD4 cell count per year, whereas HIV-1 RNA levels above 50,000 copies HIV-1 RNA per milliliter would predict a 25.3% decrease in CD4 cells per year. In addition, we estimated that the mean incubation period of disease development, as defined by the loss of CD4 below 200, is 8.2 years.
  
  
  CONCLUSIONS
  Our report on the level of viral load on predicting CD4 decline in Indian subjects with HIV-1 provides an additional important tool to the physicians for treating and planning a therapeutic strategy to control HIV-1 infection in India.
authors.affiliation: Department of Infectious Diseases, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Ding
authors.forename: Patrick
authors.initials: P
authors.lastname: Tarwater
authors.forename: Milka
authors.initials: M
authors.lastname: Rodriguez
authors.forename: Ramdas
authors.initials: R
authors.lastname: Chatterjee
authors.forename: Deena
authors.initials: D
authors.lastname: Ratner
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Yamamura
authors.forename: Pratima
authors.initials: P
authors.lastname: Roy
authors.forename: John
authors.initials: J
authors.lastname: Mellors
authors.forename: Dhruba
authors.initials: D
authors.lastname: Neogi
authors.forename: Yue
authors.initials: Y
authors.lastname: Chen
authors.forename: Phalguni
authors.initials: P
authors.lastname: Gupta
mesh_terms: D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D015658:HIV Infections / Q000276:immunology* / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology; D006801:Humans; D007194:India; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019562:Viral Load
chemical_list: D012367:RNA, Viral