title: The potential for CD4 cell increases in HIV-positive individuals who control viraemia with highly active antiretroviral therapy.
abstract: OBJECTIVE
  To study the long-term CD4 cell responses to highly active antiretroviral therapy (HAART) in treatment-naive patients whose viral loads remained below 500 copies/ml for prolonged periods.
  
  
  METHODS
  A total of 237 patients whose viral loads remained below 500 copies/ml for one year or more. Median follow-up was 1.9 years.
  
  
  METHODS
  CD4 cell counts were analysed to investigate long-term immunological response using mixed-effects models with the slope allowed to change after 1, 12 and 24 months of HAART.
  
  
  RESULTS
  The median baseline CD4 cell count was 175 cells/mm3. After an initial rapid increase in the first month after HAART (97.2 cells/mm3 a month), increases in CD4 cell counts continued less rapidly (11.6 cells/mm3 a month). This increase slowed by 2.4 cells/mm3 a month after one year. CD4 cell counts continued increasing after 2 years, but the rate of increase again slowed (estimated slope at 2 years 5.4 cells/mm3 a month; decrease in slope from year 2 compared with years 1-2 3.7 cell/mm3 a month). A total of 198 out of 211 patients (94%) with measurements at baseline and one year experienced an increase in CD4 cell counts in this interval; 81 and 67% had an increasing slope between 1 and 2 and 2 and 3 years, respectively. By the end of follow-up, CD4 cell counts had increased by 319 cells/mm3, and were more than 500 cells/mm3 in 40% of patients.
  
  
  CONCLUSIONS
  Although the rate of immune recovery slowed after 2 years, CD4 cell counts rose in most and began to return to levels seen in HIV-negative individuals.
authors.affiliation: Royal Free Centre for HIV Medicine and Department of Primary Care and Population Sciences, Royal Free and University College Medical School, Royal Free Campus, London, UK. c.smith@pcps.ucl.ac.uk
authors.forename: Colette J
authors.initials: CJ
authors.lastname: Smith
authors.forename: Caroline A
authors.initials: CA
authors.lastname: Sabin
authors.forename: Fiona C
authors.initials: FC
authors.lastname: Lampe
authors.forename: Sabine
authors.initials: S
authors.lastname: Kinloch-de-Loes
authors.forename: Helen
authors.initials: H
authors.lastname: Gumley
authors.forename: Anne
authors.initials: A
authors.lastname: Carroll
authors.forename: Beth
authors.initials: B
authors.lastname: Prinz
authors.forename: Mike
authors.initials: M
authors.lastname: Youle
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Johnson
authors.forename: Andrew N
authors.initials: AN
authors.lastname: Phillips
mesh_terms: D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D008297:Male; D019562:Viral Load; D014766:Viremia / Q000276:immunology / Q000517:prevention & control*