Correspondence

Prolonged Asymptomatic HIV-1 Infection

N Engl J Med 2000; 342:1221-1222April 20, 2000

Article

To the Editor:

The course of human immunodeficiency virus (HIV) infection is usually more severe in elderly patients than in younger patients.1 We have been following a 78-year-old man who, as a result of a test performed before cataract surgery in 1985, was found to be seropositive for HIV type 1 (HIV-1). The patient is a retired factory worker who is unmarried and heterosexual, has never taken drugs, and has never received blood transfusions. He now lives in Sardinia but previously lived in northern Italy, where he had sexual contacts with prostitutes, the most likely source of infection.

He has never had any symptoms or signs of HIV infection, and repeated clinical examinations and laboratory tests performed since 1985 have revealed no opportunistic infections or abnormalities other than HIV-1 seropositivity and glucose-6-phosphate dehydrogenase deficiency. In 1989, the patient's CD4 cell count was 580 per cubic millimeter. During the past six years, the CD8 cell count has varied from 800 to 1200 per cubic millimeter, and the CD4 cell count has consistently been greater than 350 per cubic millimeter. About 45 percent of the patient's CD4 cells were CD45RA+CD62L+ cells. A skin test for tuberculosis with purified protein derivative was positive. The patient's plasma HIV-1 RNA levels have ranged from 1000 to 4000 copies per milliliter, and the level was 1940 per milliliter in December 1999.

To investigate possible innate resistance to HIV, the patient's CCR5 gene was analyzed by polymerase chain reaction (PCR) of peripheral-blood mononuclear cells. No evidence of CCR5 mutations was found. The patient's cells could be infected in vitro with exogenous HIV-1. Both CCR5- and CXCR4- dependent strains of HIV-1 replicated in the patient's cells, and the patient's HIV-1 virus replicated in cells from a normal subject, as demonstrated by increasing concentrations of p24 antigen in supernatants of cultured cells. Major defects in the nef gene of the HIV-1 virus were ruled out by PCR with the use of primers that spanned the entire gene. Computed tomography of the chest in 1999 showed a triangular-shaped mass suggestive of thymic tissue.2

The good immunologic and clinical state of this patient with the apparent absence of innate resistance to HIV and long-term infection by a seemingly normally aggressive HIV-1 strain is difficult to explain, especially in view of his old age. It is possible that thymic regenerative capacity has been maintained in this patient, as suggested by the high proportion of CD45RA+CD62L+ cells and the results of the chest scan. These findings could explain why he has conserved immunologic responsiveness and has no symptoms of HIV infection.

Efisio Sulis, M.D., Ph.D.
General Hospital Tommasini, 08044 Jerzu, Italy

Paolo Lusso, M.D., Ph.D.
San Raffaele Scientific Institute, 20132 Milan, Italy

Licinio Contu, M.D., Ph.D.
Cagliari University, 09124 Cagliari, Italy

2 References

1. 1

   Pezzotti P, Phillips AN, Dorrucci M, et al. Category of exposure to HIV and age in the progression of AIDS: longitudinal study of 1199 people with known dates of seroconversion. BMJ 1996;313:583-586
   CrossRef | Web of Science | Medline

2. 2

   McCune JM, Loftus R, Schmidt DK, et al. High prevalence of thymic tissue in adults with human immunodeficiency virus-1 infection. J Clin Invest 1998;101:2301-2307
   CrossRef | Web of Science | Medline