Proviral HIV DNA was determined in PBMC and showed a less extended distribution, from 2 to 3.92 log10 HIV-1 DNA copies/106 PBMC, with a median value of 2.91. Proviral HIV-1 DNA at study entry was positively correlated with plasma HIV RNA (P < 0.001) and higher HIV-DNA values were associated with positive p24 antigen (P = 0.003) (Fig. 1a). In addition, proviral HIV DNA was negatively correlated with the CD4 lymphocyte count (P = 0.046) (Fig. 1b).
The clinical characteristics of patients with chronic HIV-1 infection, before the initiation of HAART, are given Table 2. The CD4 lymphocyte count ranged from 1 to 888, with a median value of 103 cells/μl. Plasma HIV-RNA levels ranged from 3.8 to 6.5 log10 HIV-1-RNA copies/ml, with a median value of 4.92. Proviral HIV DNA extended from 2 to 3.92 log10 HIV-1-DNA copies/106 PBMC, with a median value of 3.26.
The evolution of plasma HIV RNA under HAART in PRIMO subjects and the two groups of patients with chronic HIV-1 infection, naive or pre-treated, are presented in Fig. 1a. A very similar pattern of decline in plasma HIV RNA in response to treatment was observed in the three groups. Within the PRIMO group, plasma HIV-1 RNA diminished to less than 20 copies/ml for two subjects after 1 month, six subjects after 3 months, 14 subjects after 6 months, and 16 subjects after 12 months of treatment.
By comparison, the pattern of decline in proviral HIV DNA under treatment, presented in Fig. 2b, is quite different. The median level of proviral HIV DNA was 2.81 before the initiation of active antiretroviral treatment. After 1 month of treatment, the median level was 2.75 log10 DNA copies/106 PBMC, after 6 months, 2.34, and after 12 months the median level of proviral DNA attained 2.14 log10 DNA copies/106 PBMC.
When compared with the patients with chronic HIV infection who were previously naive of treatment, the median proviral HIV-DNA level, before the initiation of HAART, was significantly lower in the PRIMO group (2.81 log10 DNA copies/106 PBMC) than in the chronic group (3.59 log10 DNA copies/106 PBMC) (P = 0.02). Despite this lower level, HAART was more active on proviral HIV DNA when initiated during PHI than in the chronic phase, as evidenced by the decrease in cellular HIV-1 DNA observed after 6 months of HAART: −0.51 versus −0.30, respectively (P = 0.05) (Fig. 3). Between 6 and 12 months of treatment, a similar decrease was observed in the two groups (P = 0.42). The net result after 12 months of follow-up was of borderline significance, −0.78 log versus −0.52 (P = 0.12) (Fig. 3), perhaps because of the small sample size.
Interestingly, those patients with chronic HIV infection who were pre-treated before the initiation of PI and PRIMO subjects had similar initial levels of proviral HIV DNA (P = 0.35), but differed in their response to treatment. Indeed, the diminution in proviral HIV DNA was more pronounced in PRIMO patients (−0.78) than in chronic-phase patients (−0.32) at 12 months (P = 0.005) (Fig. 3). The pattern of decline in proviral HIV DNA observed in the three groups was thus different from that observed for plasma HIV-1 RNA (Fig. 3).
We have thus analysed whether this more pronounced decrease in PRIMO patients was dependent on the baseline proviral DNA level. The initial proviral DNA load was found to be correlated with the proviral load at 12 months (Spearman test r = 0.76, P = 0.0013), but not with the decrease in plasma viraemia achieved after 12 months (P = 0.72). Despite a homogeneous decline in plasma HIV RNA, a heterogeneous decrease in proviral HIV DNA was observed. Marked decreases in proviral HIV-1 DNA between baseline and M12 could thus be observed both in subjects with high or low levels of proviral HIV-1 DNA (Fig. 4).
Some years ago, the efficacy of combination therapy that includes a PI in suppressing HIV replication led to the belief that the early treatment of HIV-infected individuals, and in particular when initiated during PHI, might well eradicate the virus. Currently available antiretroviral therapies, however, fail to achieve this objective, even when administered soon after the first symptoms of PHI [3,4,16–19]. Nonetheless, it has been suggested that treatment at this early stage, although not eradicating the virus, might at least efficiently control viraemia and thus prevent the loss of HIV-specific CD4 T cell responses [2,5]. These HIV-specific CD4 T cell responses have been strongly and inversely correlated with the viral burden in vivo, although prolonged viral suppression caused by antiretroviral therapy has resulted in a decline in functional HIV-specific CD4 T cells . Nevertheless, early treatment during PHI does appear to provide an immunological benefit, as evidenced by the persistence of HIV-specific CD4 responses in PRIMO subjects on active antiretroviral therapy (Venet et al., personal communication).
In patients under HAART, plasma viraemia is rapidly suppressed to undetectable levels [3,4,14,19,21–29], even though low-level replication is ongoing. For this reason, proviral HIV DNA could be a more informative marker than plasma HIV RNA with which to assess the long-term impact of treatment . It is not known to what extent this low-level replication is responsible for replenishing the pool of HIV-infected cells, but our results indicate that HAART can reduce the proviral HIV-DNA load more efficiently when initiated during PHI than during the chronic phase. Our results also underscore the importance of effective initial treatment, even when initiated in the chronic phase. Indeed, although the median decrease in proviral HIV DNA observed in patients who were previously naive of treatment was −0.72 and −0.52 for individuals with primary and chronic HIV-1 infection, respectively, this decrease was less pronounced (−0.32 log) in pre-treated chronic-phase patients. Zaunders et al. , however, reported that untreated PHI patients and patients treated within 45–90 days from the onset of symptoms had comparable HIV-DNA levels, and therefore suggested that HAART had little effect on the HIV-DNA burden established after acute infection. We cannot rule out the hypothesis that the more pronounced effect of early HAART treatment relative to delayed HAART on the proviral decline could be ascribed to the evolving immune response during the acute phase of infection. Early HAART treatment would be beneficial by preventing ongoing dissemination and thus by maintaining a low viral DNA reservoir.
Taken together, our results argue in favour of the therapeutic advantage of early treatment of HIV infection, and lend support to the early initiation of therapy. Nevertheless, this view should be tempered by the fact that lifelong treatment may be required. Indeed, treated patients face problems of tolerance owing to the numerous side-effects and toxicity of retroviral inhibitors, as well as problems of therapeutic failure, underscoring the limitations of long-term therapy, which would be even further strained were treatment initiated in primary infection.
Moreover, before the initiation of treatment certain PRIMO patients not only had a high CD4 cell count, but also low levels of plasma HIV RNA and proviral HIV DNA. We may hypothesize that some of those individuals are capable of spontaneously controlling virus replication for years without any treatment. We could thus spare side-effects or toxicity such as lipodystrophy, which may even occur in PHI-treated patients. Why some PRIMO patients had low viral burdens while others had high burdens is not yet understood. The level of proviral DNA is probably peculiar to the individual, because host genetic factors, such as chemokine receptor gene polymorphisms, which are determinants for disease progression  and the response to treatment [34,35], are likely to be involved in the establishment of the pool of HIV-infected cells.
Our study shows that heterogeneous viral loads are observed early after PHI and that, upon the initiation of HAART, responses are heterogeneous. Further studies are needed to assess the predictive value of the HIV-DNA level for the infection outcome. The quantitative analysis of proviral DNA, before the initiation of antiretroviral therapy, could be a constructive marker for arguing for treatment of PHI. At present, because of the growing evidence on the side-effects and toxicity of HAART and the need for lifelong treatment, some physicians question the moment of treatment initiation for PHI patients, in that some of them might spontaneously control viral replication for years. A large-scale randomized study of early therapy with careful proviral load assessment is thus needed to delineate further the moment to commence antiretroviral therapy in the primary infection period.
The authors are indebted to the patients enrolled in the French PRIMO Cohort Study and to our clinician colleagues, without whom none of these studies would have been possible. The authors gratefully acknowledge the French HIV Quantification Group for data concerning HIV-1-infected patients in chronic phase. They would also like to thank Dr J. Richardson for reviewing the manuscript.
1. Rosenberg ES, Billingsley JM, Caliendo AM. et al
. Vigorous HIV-1-specific CD4+ T cell responses associated with control of viremia. Science 1997, 278: 1447 –1450.
2. Musey LK, Krieger JN, Hughes JP, Schaker TW, Corey L, McElrath MJ. Early and persistent human immunodeficiency virus type 1 (HIV-1)-specific T helper dysfunction in blood and lymph nodes following acute HIV-1 infection. J Infect Dis 1999, 180: 278 –284.
3. Markowitz M, Vesanen M, Tenner-Racz K. et al
. The effect of commencing combination antiretroviral therapy soon after human immunodeficiency virus type 1 infection on viral replication and antiviral immune responses. J Infect Dis 1999, 179: 525 –537.
4. Zaunders JJ, Cunningham PH, Kelleher AD. et al
. Potent antiretroviral therapy of primary human immunodeficiency virus type 1 (HIV-1) infection: partial normalization of T lymphocyte subsets and limited reduction of HIV-1 DNA despite clearance of plasma viremia. J Infect Dis 1999, 180: 320 –329.
5. Oxenius A, Price DA, Easterbrook PJ. et al
. Early highly active antiretroviral therapy for acute HIV-1 infection preserves immune function of CD8+ and CD4+ T lymphocytes. Proc Natl Acad Sci U S A 2000, 97: 3382 –3387.
6. Sinicco A, Fora R, Sciandra M, Lucchini A, Caramello P, Gioannini P. Risk of developing AIDS after primary acute HIV-1 infection. J Acquir Immune Defic Syndr 1993, 6: 575 –581.
7. Boufassa F, Bachmeyer C, Carre N. et al
. Influence of neurologic manifestations of primary human immunodeficincy virus infection on disease progression. J Infect Dis 1995, 171: 1190 –1195.
8. Watson A, Ranchalis J, Travis B. et al
. Plasma viremia in macaques infected with simian immunodeficiency virus: plasma viral load early in infection predicts survival. J Virol 1997, 71: 284 –290.
9. Haigwood N, Watson A, Sutton WF. et al
. Passive immune globulin therapy in the SIV/macaque model: early intervention can alter disease profile. Immunol Lett 1996, 51: 107 –114.
10. Lee T-H, Sheppard HW, Reis M, Dondero D, Osmond D, Busch MP. Circulating HIV-1 infected cell burden from postseroconversion to AIDS: importance of postseroconversion viral load on disease course. J Acquir Immune Defic Syndr 1994, 7: 381 –388.
11. Mellors JW, Kingsley LA, Rinaldo CR Jr. et al
. Quantitation of HIV-1 RNA in plasma predicts outcome after seroconversion. Ann Intern Med 1995, 122: 573 –579.
12. Hubert J-B, Burgard M, Dussaix E. et al
. Natural history of serum HIV-RNA levels in 330 patients with a known date of infection. AIDS 2000, 14: 123 –131.
13. Dalod M, Dupuis M, Deschemins J-C. et al
. Weak anti-HIV CD8+ T-cell effector activity in HIV primary infection. J Clin Invest 1999, 104: 1431 –1439.
14. Burgard M, Izopet J, Dumon B. et al
. HIV RNA and HIV DNA in peripheral blood mononuclear cells are consistent markers for estimating viral load in patients undergoing long-term potent treatment. AIDS Res Hum Retroviruses 2000, 16: 1935 –1943.
15. Christopherson C, Kidane Y, Conway B, Krowka J, Sheppard H, Kwok S. PCR-based assay to quantify human immunodeficiency virus type 1 DNA in peripheral blood mononuclear cells. J Clin Microbiol 2000, 38: 630 –634.
16. Chun T-W, Engel D, Berrey MM, Shea T, Corey L, Fauci AS. Early establishment of a pool of latently infected, resting CD4+ T cells during primary HIV-1 infection. Proc Natl Acad Sci USA 1998, 95: 8869 –8873.
17. Hoen B, Dumon B, Harzic M. et al
. Highly active antiretroviral treatment initiated early in the course of symptomatic primary HIV-1 infection: results of the ANRS 053 trial. J Infect Dis 1999, 180: 1342 –1346.
18. Lillo FB, Ciuffreda D, Veglia F. et al
. Viral load and burden modification following early antiretroviral therapy of primary HIV-1 infection. AIDS 1999, 13: 791 –796.
19. Poggi C, Profizi N, Djediouane A, Chollet L, Hittinger G, Lafeuillade A. Long-term evaluation of triple nucleoside therapy administered from primary HIV-1 infection. AIDS 1999, 13: 1213 –1220.
20. Pitcher CJ, Quittner C, Peterson DM. et al
. HIV-1-specific CD4+ T cells are detectable in most individuals with active HIV-1 infection, but decline with prolonged viral suppression. Nat Med 1999, 5: 518 –525.
21. Chun T-W, Stuyver L, Mizell SB. et al
. Presence of an inducible HIV-1 latent reservoir during highly active antiretroviral therapy. Proc Natl Acad Sci U S A 1997, 94: 13193 –13197.
22. Furtado MR, Callaway DS, Phair JP. et al
. Persistence of HIV-1 transcription in peripheral blood mononuclear cells in patients receiving potent antiretroviral therapy. N Engl J Med 1999, 340: 1614 –1622.
23. Dornadula G, Zhang H, Van Uitert B. et al
. Residual HIV-1 RNA in blood plasma of patients taking suppressive highly active antiretroviral therapy. JAMA 1999, 282: 1627 –1631.
24. Hockett RD, Kilby JM, Derdeyn CA. et al
. Constant mean viral copy number per infected cell in tissues of high, low or undetectable plasma HIV RNA. J Exp Med 1999, 189: 1545 –1554.
25. Natarajan V, Bosche M, Metcalf JA, Ward DJ, Lane CH, Kovacs J. HIV-1 replication in patients with undetectable plasma virus receiving HAART. Lancet 1999, 353: 119 –120.
26. Romano L, Venturi G, Catucci M, De Milito A, Valensin PE, Zazzi M. Evaluation of cell-free and cell-associated peripheral blood human immunodeficiency virus type 1 RNA response to antiretroviral therapy. J Infect Dis 1999, 179: 361 –366.
27. Zhang L, Ramratnam B, Tenner-Racz K. et al
. Quantifying residual HIV-1 replication in patients receiving combination antiretroviral therapy. N Engl J Med 1999, 340: 1605 –1613.
28. Sharkey ME, Teo I, Greenough T. et al
. Persistence of episomal HIV-1 infection intermediates in patients on highly active anti-retroviral therapy. Nat Med 2000, 6: 76 –81.
29. Ramratnam B, Mittler JE, Zhang L. et al
. The decay of the latent reservoir of replication-competent HIV-1 is inversely correlated with the extent of residual viral replication during prolonged anti-retroviral therapy. Nat Med 2000, 6: 82 –85.
30. Mc Dermott JL, Giri AA, Martini I. et al
. Level of human immunodeficiency virus DNA in peripheral blood mononuclear cells correlates with efficacy of antiretroviral therapy. J Clin Microbiol 1999, 37: 2361 –2365.
31. Schacker T, Little S, Connick E. et al
. Rapid accumulation of human immunodeficiency virus (HIV) in lymphatic tissue reservoirs during acute and early HIV infection: implications for timing of antiretroviral therapy. J Infect Dis 2000, 181: 354 –357.
32. Cone RW, Gowland P, Opravil M, Grob P, Lerdergerber B, and the Swiss HIV Cohort study. Levels of HIV-infected peripheral blood cells remain stable throughout the natural history of HIV-1 infection. AIDS 1998, 12: 2253 –2260.
33. Berger EA, Murphy PM, Farber JM. Chemokine receptors as HIV-1 coreceptors: roles in viral entry, tropism, and disease. Ann Rev Immunol 1999, 17: 657 –700.
34. O'Brien TR, Mc Dermott DH, Ioannidis JPA. et al
. Effect of chemokine receptor gene polymorphisms on the response to potent antiretroviral therapy. AIDS 2000, 14: 821 –826.
35. Guerin S, Meyer L, Theodorou I, et al. CCR5 Δ32 deletion and response to HAART in HIV-1-infected patients. 7th Conference on Retroviruses and Opportunistic Infections
. San Francisco, CA, 2000 [Abstract 452].
Primo Cohort Study Group: C. Caulin, J. Cervoni, E. Badsi (Lariboisière, Paris); F. Raffi, V. Reliquet, E. Billaud, J.L. Esnault (Hôtel-Dieu, Nantes); A.P. Blanc, T. Allegre (Aix en Provence); M. Dorra, J. Derouineau, S. Morelon, E. Rouveix (A. Paré, Boulogne); G. Sobesky, S. Abel, A. Cabié (Fort de France); P. Henon, G. Beck-Wirth (Emile Muller, Mulhouse); C. Bazin, M. Six, R. Verdon (Caen); S. Herson, N. Amirat, J. Dagron (Pitié-Salpétrière, Paris); J. Beylot, P. Morlat, D. Malvy, M. Bonarek (Saint André, Bordeaux); P. Morel, F. Timsit (St Louis, Paris); J.P. Cassuto, C. Sohn (L'Archet, Nice); J.L. Vildé, C. Jestin, C. Jadand, U. Colasante (Bichat, Paris); J.F. Delfraissy, C. Goujard, X. Copin, Y. Quertainmont (Bicêtre, Le Kremlin Bicêtre); D. Sicard, D. Salmon, G. Spiridon (Cochin, Paris); G. Charpentier, P. Chevojon (Corbeil); J. Achard, P. Fialaire (Angers); F. Vachon, E. Bouvet, I. Fournier (Bichat, Paris); J.F. Bach, J.P. Viard (Necker, Paris); B. Dupont, C. Joly (Pasteur, Paris); R. Laurent, C. Drobacheff, Y. Bourezane (St Jacques, Besançon); H. Gallais, A.M. Quinson, I. Ravaux (La Conception, Marseille); P. Dellamonica, S. Chailloux (L'Archet, Nice); M. Kazatchkine, D. Laureillard (Broussais, Paris); J. Beytout, C. Jacomet (Hôtel Dieu, Clermont-Ferrand); J. Laffay, A. Greder Belan (A. Mignot, Le Chesnay); J.C. Imbert, O. Picard (St Antoine, Paris); O. Bletry, D. Zucman (Foch, Suresnes); P. Galanaud, F. Boué (A. Béclère, Clamart); J.C. Messmer, B. Delmas (Joffre, Perpignan); Ph. Vinceneux, A.M. Simonpoli (L. Mourier, Colombes); A. Sobel, P. Lesprit (H. Mondor, Créteil); M. Gayraud, L. Bodard (I.M.M. Jourdan, Paris); D. Sereni, C. Lascoux (St Louis, Paris); M. Chousterman, O. Launay (Créteil); T. Colin, V. Launay (Cherbourg); P. Chavanet, M. Buisson (Dijon); F. Jambon, V. Baillat (Montpellier); D. Merrien (Compiegne); G. Dien, C. Hascoet (Saint Brieuc); D. Houlbert (Alençon); J.P. Clauvel, L. Gérard (St Louis, Paris); J.P. Coulaud, M. Saada (Bichat, Paris); G. Guermonprez, A. Dulioust (Briis s/Forges); Gonzalez, F. Sanlaville (Sens); C. Miodovski (Paris); P. Boudon, D. Malbec (R. Ballanger, Aulnay Sous Bois); J. Deville, I. Beguinot (Robert Debré, Reims).