the hiv seropositivity revealed by an antibody test is indicative of virus 
 infection . due to a small proportion of false - positive , false - negative , and 
 ambiguous ( indeterminate ) findings occurring in a general population , this test 
 is not perfect but remains , however , the first - line laboratory procedure for 
 diagnostic purposes . it is currently accepted that antibody tests are nearly 
 100% sensitive and about 99% specific [ 1 , 2 ] . the frequency of false - positive 
 hiv serology in a low - prevalence population , for example , military recruits 
 from rural united states , is 1/135 000 , while for blood donors in minnesota 
 is 6/million . a survey of 5 million blood donors ' samples found that the 
 prevalence of false positives was 1/251 000 . to reduce the chances of 
 technical or clerical error , the antibody tests are confirmed by additional 
 tests like elisa , western blot , and pcr analysis . when tests are combined , for 
 example , elisa and western blot , the false - positive rate has been reported to 
 be as low as 1/100 000 . others have indicated that even when tests are 
 combined , about 3% of the investigated sera were false - positive , 
 false - negative , or noninterpretable . it is extremely unusual when symptomatic or 
 asymptomatic individuals with culture- or pcr - confirmed hiv infection do not 
 produce virus - directed antibodies and remain persistently negative beyond the 
 expected window period . a few such cases have been reported in the literature , and 
 most of which were due to agammaglobulinemia of unknown immune dysfunction [ 511 ] . these exceptions only reinforce the general notion that once a person is 
 diagnosed with hiv , he or she remains antibody - positive for the rest of his or 
 her life . however , with the exception of very few instances , these infants 
 are not hiv - infected . occasionally , this has been observed among individuals who 
 were at the terminal stage of disease [ 14 , 15 ] . cases of spontaneous 
 seroreversion among patients from other categories are exceedingly rare [ 1618 ] . in addition to cases of spontaneous loss of 
 antibodies , there are several reports attributing this phenomenon to iatrogenic 
 intervention , referred to as serodeconversion . the earliest known report is 
 related to administration of low - dose oral interferon , whereby 18 out of 204 treated 
 patients became hiv - negative . two recent 
 reports have shown for the first time that patients with acute or early hiv 
 infection may lose hiv antibodies as a result of highly active antiretroviral 
 therapy [ 21 , 22 ] , supporting the notion that serodeconversion seldom occurs in 
 patients on antiviral therapy . finally , both therapeutic aids vaccines 
 produced from the blood of hiv patients , that is , nigerian abalaka 's vaccine 
 and cameroonian anomah ngu 's vaccine , were reported to produce serodeconversion 
 in several dozen aids patients [ 23 , 24 ] . v-1 immunitor ( v1)the first 
 commercial therapeutic aids vaccine  has been registered 
 by the thai fda as a food supplement and experimental drug . the vaccine 
 comprises heat - inactivated hiv antigens derived from pooled blood of 
 hiv - infected donors . extensive preclinical studies have shown that v1 is safe . 
 in a longitudinal survey in 400 patients , about 85% reported improvement , 6% 
 reported no difference , and 9% reported minor adverse reactions , which did not 
 last more than one week . our earlier open - label and subsequent 
 placebo - controlled clinical studies have shown that v1 administration increases 
 absolute cd4 and cd8 cell counts in both hiv - positive and hiv - negative subjects 
 [ 2729 ] . other clinical benefits included the reversal of 
 aids - associated wasting and normalization of elevated liver enzymes in 
 hiv - positive patients coinfected with hepatitis viruses . patients on v1 
 rarely develop new fungal or bacterial infections , suggesting that v1 restores 
 the mucosal immune response to opportunistic infections . finally , in a 
 survival study , the end - stage aids patients had 15.8 times longer life 
 expectancy than those who declined v1 treatment . this single clinical 
 endpoint is clearly more important than surrogate endpoints such as viral load 
 and t - cell counts . in this study , we analyze yet another phenomenon associated 
 with v1 therapy , that is , an observation that some aids patients who received 
 v1 became hiv - antibody - negative . sixty thousand patients from thailand with documented history of hiv infection have received or are currently 
 receiving v1 . in this retrospective survey , every patient who became aware of 
 hiv - antibody - negative status following treatment with v1 was considered for the 
 analysis . patients who did not have reliable antibody test , traceable to the 
 original issuing lab , were not included and only those with confirmed 
 serodeconversion as compared to baseline status were included in this survey . the physical examination and patients ' interviews were performed at rajavithi general hospital 
 in bangkok . the dose for 
 children was twice smaller . with the exception of one patient ( no . 22 ) , none of 
 them received conventional antiretroviral therapy or participated in any aids 
 vaccine trials conducted in thailand during treatment period . 22 , a two - year - old boy 
 from tanzania , was on azt monotherapy for a few months shortly after the birth but due to drug 
 intolerance and lack of clinical improvement he discontinued treatment before 
 starting on v1 . v-1 immunitor ( v1 ) is derived from specially processed heat and chemically inactivated , 
 pooled blood of hiv - infected thai donors . the vaccine is formulated into an 
 oral tablet according to a proprietary process developed by us . as pooled blood 
 from unrelated donors was used for vaccine manufacturing , v1 can be regarded as 
 an allovaccine since in addition to viral proteins it also contains 
 alloantigens from the blood . the vaccine is manufactured in thailand by immunitor ( thailand ) co. , ltd . , and is 
 approved by thai food and drug administration ( fda ) as 
 a dietary supplement and investigational drug . v-1 immunitor is provided as 850 
 mg coated tablet  ten of which are 
 sealed in a most of patients ' sera were examined by rapid tests for hiv antibodies ( bioline 
 hiv1/2 , immunochemical lab , thailand and determine hiv1/2 abbott / dainabot , japan ) . another approved antibody test used in thailand as a second - line test is elisa 
 or enzyme immunoassay ( eia ) . these tests are also commercially available : uni - form 
 ii ag / ab kit ( organon technika , the netherlands ) or hiv1/2 
 ( abbott laboratories , usa ) . occasionally , latex 
 particle agglutination test ( gpa , serodia - hiv 1/2 , fujirebio inc . , japan ) the choice of second - line tests depended 
 on their availability at the testing lab and patients ' ability to pay for them . 
 in some cases , commercial western blot assay was conducted in addition to 
 antibody tests ( hiv blot 2.2 , genelabs diagnostics , singapore ) . as tests were performed in different labs , the qa / qc standards may vary but 
 these variables were beyond our control due to retrospective nature of this 
 study . plasma viral concentrations were measured at various independent hospitals and 
 commercial labs at patients ' own choice . as pcr tests are expensive , very few 
 patients were able to afford such tests . depending on the individual lab , the commercial 
 viral load kits were used without any specific preference . these quantitative pcr 
 kits were either rna pcr kit ( roche diagnostic systems , inc . , branchburg , nj , usa ) 
 or branched dna kit ( bayer , tarrytown , nj , usa ) . 
 the sensitivities of these tests were 400 and 50 viral copies per ml , respectively . in addition , qualitative tests for hiv-1 were performed by in - house developed 
 pcr method according to our own published protocol . the lowest detection 
 threshold of this test was estimated to be not less than 100 hiv copies per ml . data were analyzed with statmost software version 2.5 ( datamost corporation , 
 salt lake city , utah , usa ) and sisa  free online program  with courtesy of 
 daan uitenbroek . the odds ratio ( or ) was estimated at 95% wald confidence interval ( ci ) . for assessment 
 of correlation between seronegative status and viral load , we have used nonparametric 
 spearman 's rank - order test . the significance level for all tests the patient group consisted of 9 females ( 39% ) and 14 males ( 61% ) including 2 two - year - old 
 boys . ages ranged within 258 years with a 
 mean age of 29 years ( median age = 29.5 years ) . the duration of v1 treatment 
 until a patient sought to check the antibody status ranged between 2 weeks and 
 15 months with an average of 7.2 months ( median range = 8 months ) . all patients 
 were tested for hiv seropositivity prior to administration of v1 . while most of 
 them were tested only once before treatment initiation , on average , once patients knew the seronegative status , 
 many of them had tests repeated , often at different labs to ascertain that they 
 were truly negative . thus , the average number of post - treatment tests was 
 slightly higher ( 3 tests ) but not statistically significant . the results are 
 summarized in table 1 which shows only those tests for which we have traceable 
 records . at baseline , we had 13 ( 56.5% ) patients who 
 qualified as having full - blown aids , while the remaining 2 ( 8.7% ) and 8 ( 34.8% ) 
 patients had the who stage 2 and 3 symptoms , respectively . since patients with 
 fewer symptoms were recovering faster , the correlation analysis was conducted 
 to see if there is a relation between severity of disease and time to 
 serodeconversion . the results indicate that earlier you start treatment , faster 
 you expect to see the disappearance of hiv antibodies ( spearman 's rank 
 correlation , r = 0.620793 ; p = .0015773 ) . in nine patients , viral loads were barely detectable 
 or undetectable after treatment , but unfortunately four of these patients had no 
 matching pcr tests at study entry . qualitative pcr tests which were conducted 
 at the end of study were either positive or negative . but the majority of 
 patients had not tested for viral load primarily due to the fact that they 
 could not afford expensive pcr tests . nevertheless , from what is available to 
 us , there is a clear impression that serodeconversion correlates with lowered 
 or undetectable viral load . unfortunately , we do not have the complete pairwise 
 set of data to confirm this impression by a robust parametric test . we thus have 
 performed nonparametric spearman 's rank order correlation analysis on available 
 outcome results , that is , nine patients : nos . 1 , 2 , 3 , 6 , 8 , 9 , 10 , 11 , and 23 . we assume that four patients  nos . 3 , 6 , 8 , and 23had positive pcr 
 results prior to the therapy . each viral load test , whether positive or 
 negative , was entered as a binary value . 1 had three 
 negative results and a total of 3 were entered into negative results ' column ; 
 patient no . 3 had 2 negatives and 1 positive reading , which were entered into 
 negative and positive results ' columns , respectively . in this manner , we have constructed a two - way 
 table to evaluate whether hiv - seronegative status had any association with 
 negative or positive pcr results . the results revealed positive linear 
 relationship with r = 0.64842 at p = .000819 . another reliable test that could be performed on 
 available data is establishment of the odds ratio , which could tell whether our 
 findings differ from published incidence of false - positive or false - negative 
 results in large populations of individuals screened for hiv antibodies . such a 
 statistical test was aimed to reveal whether the observed incidence of 
 serodeconversion , that is , 23 individuals out of 60000 , could happen randomly as 
 a result of laboratory error . this analysis was performed in 2  2 contingency 
 table comparing side by side our data with published surveys of diagnostic 
 accuracy of hiv tests . as can be seen 
 from table 2 , what we have observed is statistically different in every single 
 case . all obtained or values were distant from 1a ratio that one would 
 expect to see if there was no difference between our outcome and frequencies reported 
 by others . due to the retrospective nature of this study , the data , especially concerning 
 viral load , are incomplete . nevertheless , it is clear that obtained results are 
 highly unusual . why would previously hiv - antibody - positive patients become 
 seronegative after treatment with v1 ? the possibility that all these patients were 
 false - positive at the baseline is unlikely since they were symptomatic and 
 sought v1 treatment because they were suffering from aids - related symptoms . these symptoms , that is , low cd4 counts ; weight loss ; a whole range of opportunistic 
 infections : such as oral thrush , tb , skin lesions , persistent diarrhea , and in one case 
 even kaposi 's sarcoma , were severe enough to score them as belonging to advanced 
 disease stage . one may argue that clinical symptoms were not hiv - related 
 and all these patients were initially false - positive due to random incidence of 
 such cases in general population . this scenario , however , remains highly 
 unlikely since , according to the  normal  incidence of false positives in healthy 
 individuals , one would expect no more than 1/4 ( 0.25% ) to 1/2 ( 0.5% )   false - positive 
 persons among 60000 v1-treated individuals . on the contrary , in 
 placebo - controlled , randomized phase ii clinical trial of v1 published in 2004 , 
 we have shown that one out of 29 v1-treated patients became hiv - negative , 
 suggesting much higher conversion rate . the cases of true , confirmed 
 seroreversion , that is , a seroreactive or positive sample with subsequently one 
 or more nonreactive samples from the same person , are extremely rare [ 1018 ] . in fact , most , if not all , cases of apparent seroreversion seem to be errors of 
 attribution or lab testing [ 14 ] . a survey on 2 580 974 army recruits 
 identified 4911 seropositive individuals by two independent samples , among whom 
 only six were potential seroreverters . further review of these cases 
 revealed that five actually were hiv - seroreactive patients who had samples from 
 nonreactive individuals mistakenly attributed to them , while the sixth had a 
 testing error . mistakes in the testing process were identified in other 26 
 cases indicating the cumulative error rate of 12.4 per 1 million individuals . 
 in this paper , we included only those patients who had confirmed tests 
 traceable to the original testing lab and excluded anyone who had indeterminate 
 results or whose records could not be traced . the odds ratio analysis comparing 
 our data with published reports of false - positive or false - negative cases in 
 large surveys rules out that what we have observed is a random event due to 
 testing error ( see table 2 ) . even the two infants in our study who were born to 
 hiv - positive mothers are unlikely to be false - positive since they were both 
 symptomatic and tested repeatedly positive past the age of 18 months , a 
 timepoint by which the newborns lose maternal antibodies [ 12 , 13 ] . table 1 , 
 however , shows only one positive baseline test for each of the boys since other 
 tests could not be traced to original issuing labs . as on average , it took 78 months and as 
 long as 15 months to attain seronegative status ; the two - week period appears to 
 be very short . nevertheless , considering that half life of anti - p24 igg immunoglobulin 
 is 1119 days , it is 
 possible that hiv antibodies were still present but their levels have decreased 
 below detection limit of standard assays . this possibility is not entirely 
 implausible . the antibody tests of some of the patients were fluctuating from 
 positive to negative and back to positive during the therapy suggesting that the 
 levels of anti - hiv antibodies were at the borderline of detection threshold . 3 , 9 , 10 , and 11were still 
 showing the presence of the virus as detected by pcr analysis . latter situation 
 is reminiscent of extensively studied high - risk seronegative ( hrsn ) individuals 
 who have remained hiv - negative despite repeated exposure to the virus . it has 
 been shown recently that hrsns often carry extraordinary low levels of hiv-1 
 dna . however , as opposed to our patients , these individuals are free of 
 disease symptoms and are commonly known as long - term survivors . it is not unusual to see the decline in antibodies 
 in very late stage of hiv disease which may be explained , in part , by higher 
 viral burden and reduced availability of circulating antibodies due to antibody - antigen 
 complex formation . in our situation , as there is a documented decrease in viral 
 burden , we would expect to see a surplus of antibodies rather than their 
 reduction . it 
 was correlated with baseline disease stage , meaning that those who are better 
 off initially were likely to require less time to convert than those with advanced 
 disease ( r = 0.62 ; p = .002 ) . 17 , 6 , and 7who converted to 
 seronegative status under one - month time were all in earlier disease stage . the therapeutic vaccination was first 
 introduced into clinical practice by the french researcher daniel zagury as a 
 treatment option for aids more than 20 years ago . due to inherent problems 
 associated with haart , however , nearly 30 therapeutic vaccine candidates were tested in over 60 
 clinical trials , but they have not produced any evidence of clinical benefit , 
 let alone serodeconversion . abalaka and ngu , thivac and vanhivax , respectively , which produced favorable clinical outcomes and have caused serodeconversion in some of their patients [ 23 , 24 ] . their results provide further support to a possibility 
 that what we have observed with v1 is not due to testing or clerical error . from the immunological point of view , 
 this phenomenon seems to be related to an observation first made by stott , who 
 reported that macaques vaccinated with a preparation of whole killed human 
 cells infected with siv were fully protected against subsequent challenge . curiously , animals immunized with a control preparation consisting of killed 
 human cells without siv were also protected . this observation appears to relate 
 to the fact that during the budding process through the cell membrane , siv as 
 well as hiv acquires several hundred host cell molecules . thus , the 
 immunization with host 's proteins was equal to or more effective than immunization 
 with viral antigens . while the interpretation of stott study has been 
 contested , several studies appear to be in agreement with this seemingly 
 unusual finding . for example , lopalco et al . reported that the enigmatic 
 phenomenon of exposure to hiv without seroconversion was associated with 
 anticell auto - anti - bodies but not with hiv - neutralizing antibodies directed 
 against viral antigens . sera from polytransfused , hiv - negative individuals 
 who often develop immune responses against themselves , 
 including anti - hla antibodies , were shown to neutralize hiv-1 . the concept that aids is an autoimmune disease and thus alloimmunization or in other 
 words , immunization with autologous cellular antigens with or without hiv antigens , as a 
 basis for immune - based therapy of hiv has been advocated at length by us and others [ 42 , 43 ] . several therapeutic approaches based on this concept have been 
 proposed . daniel zagury , who pioneered therapeutic hiv immunization , made his original 
 vaccine from formaldehyde - treated leukocytes derived from the blood of seropositive 
 patients . his vaccine has shown dramatic clinical improvements , but unfortunately 
 his work has not been followed . the autologous t - cell vaccination developed by 
 abulafia - lapid et al . has shown encouraging results with over 50% ( median of 
 70% ) increase in cd4 cell counts . their vaccine consists of in vitro propagated , 
 glutaraldehyde - inactivated , autologous t cells which are injected back to 
 hiv - positive donors . remune is another vaccine in this category ; however , 
 due to the purification process of virus particles from the supernatant of cell 
 culture , it may not possess sufficient quantity of alloantigens , which may 
 explain persistent incertitude in clinical effect . oral feeding of alloantigens , as in case of v1 , is an approach that makes sense since it induces immune tolerance a strategy that has been shown effective in therapy of chronic hepatitis b and c  diseases that are caused by autoimmune reaction against virus - carrying liver cells rather than direct cytopathic effect of hepatitis viruses [ 4648 ] . israeli 
 et al . have shown that oral feeding of hepatitis b antigens in combination with 
 allogeneic liver cells to patients with chronic hepatitis leads to a 
 dose - dependent reduction of anti - hbv antibody titers  an observation 
 that supports , albeit indirectly , our findings . in fact , we have shown 
 earlier that oral administration of v1 to normal healthy volunteers does not induce 
 systemic anti - hiv antibodies . these investigations relate to the often ignored 
 notion of autoimmune nature of aids as a disease [ 42 , 43 ] . if this concept is 
 correct , then the prevailing aids vaccine strategy aimed at activating the 
 immune response against hiv instead of inducing immune tolerance is flawed . results 
 of recent trial of therapeutic aids vaccine in which hiv - directed immune activation 
 was associated with increase in viral load further support this notion . the 
 observed phenomenon of loss of antibodies against hiv and clinical improvement can 
 be readily explained by tolerance induction . due to paucity of guiding 
 precedents relating to serodeconversion [ 5052 ] , the present findings need to 
 be interpreted cautiously and additional case studies have to be acquired and 
 analyzed to rule out any possible error .