Isolation of a new HIV-2 group in the US

Infection with human immunodeficiency virus type 2 (HIV-2) is endemic in some countries of West Africa. Unlike infection with HIV type 1 (HIV-1), this infection has not appreciably spread beyond this area. The incidence of HIV-2 infection has even declined over the last 16–20 years [1,2]. The majority of human infections are caused by groups A or B, which have been referred to as the epidemic groups. The rate of progression to acquired immunodeficiency syndrome (AIDS) for the epidemic strains is not well defined[3]. However, variation in envelope during infection is similar to that seen in HIV-1[4]. Infections with non-epidemic subtypes (C-G) are known only as single person infections and available evidence indicates that infection did not lead to immune suppression[5]. The one noted exception is a group H virus, which caused immunodeficiency in a man from the Ivory Coast[6].Sixteen years ago, infection with HIV-2 Group F was described in one individual from the northern province of Sierra Leone[7]. HIV-2 Group E was also found in a single person originating from Sierra Leone and was reported 18 years ago[5]. Virus was not isolated from either person, despite repeated attempts. Both individuals were healthy during the time of observation. Here we present evidence that a Group F virus isolated in 2008 appears to be a newly emerging HIV-2 group. The virus, HIV-2-NWK-08F, was isolated from a man with CD4 T-cell lymphopenia.Patient X is a 68 year old male from Freetown, Sierra Leone. Patient X immigrated to the New Jersey, USA. in 2007. During the immigration process, he tested positive for antibodies against HIV. He was referred to the Peter Ho Memorial Clinic in Newark, New Jersey for follow-up and treatment in early 2008. Patient X's serum was repeatedly reactive by serological testing with ELISA kits containing HIV-1 and HIV-2 antigens. The western blot for HIV-1 was negative. His HIV-1 viral load was <48 copies and polymerase chain reaction (PCR) for HIV-1 proviral