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ORIGINAL ARTICLE Table of Contents   
Year : 2009  |  Volume : 52  |  Issue : 3  |  Page : 353-356
Serological profile of HSV-2 in patients attending STI clinic: Evaluation of diagnostic utility of HSV-2 IgM detection


1 Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi - 110 095, India
2 Department of Dermatology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi - 110 095, India

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Date of Web Publication12-Aug-2009
 

   Abstract 

Objective: The present study was done to evaluate the serological profile of herpes simplex virus-2 (HSV-2) among patients attending sexually transmitted infections (STI) clinic and to determine the utility of detecting HSV-2 IgM antibodies in such patients. A correlation of HSV-2 infection with other STI including HIV has also been attempted. Materials and Methods: Hundred consecutive patients who attended STI clinic, with one or more of the complaints as enunciated by WHO in syndromic approach for the diagnosis of STI, were included as subjects. All subjects were screened for common STI by standard laboratory procedures/ commercially available kits. HSV-1 and HSV-2 IgM antibody was detected by commercially available enzyme immuno assay kit in all patient's sera. Sera were also tested for other STI, namely HIV, Hepatitis B virus, Hepatitis C virus and Treponema pallidum. Antigen detection for Chlamydia trachomatis was done in genital swabs of all patients by Bio-Rad Chlamydia Microplate EIA 31189 (United States) kit. Results: Thirty patients were found to have genital herpes. In 17/30 (56.6%) patients, HSV-2 serology was found to correlate with the clinical diagnosis. The coexistence of other infection in HSV-2 seropositive patients was detected in 8/30 patients. None of the patients having concomitant infections were clinically diagnosed accurately. Sensitivity, specificity, positive predictive value and negative predictive value of IgM antibodies for the diagnosis of genital herpes was 73.91%, 90.91%, 70.83% and 92.91% respectively. Conclusion: HSV-2 IgM detection could only be used as a supportive test for the diagnosis of genital herpes . It needs to be emphasized that the sensitivity and positive predictive value scores are pointers for further improvement in the commercial assay systems and a large sample size may determine the broader utility of such systems.

Keywords: Co-infection, HSV-2 IgM, HIV, sexually transmitted infections, statistical indices

How to cite this article:
Choudhry S, Ramachandran V G, Das S, Bhattacharya S N, Mogha NS. Serological profile of HSV-2 in patients attending STI clinic: Evaluation of diagnostic utility of HSV-2 IgM detection. Indian J Pathol Microbiol 2009;52:353-6

How to cite this URL:
Choudhry S, Ramachandran V G, Das S, Bhattacharya S N, Mogha NS. Serological profile of HSV-2 in patients attending STI clinic: Evaluation of diagnostic utility of HSV-2 IgM detection. Indian J Pathol Microbiol [serial online] 2009 [cited 2019 Apr 23];52:353-6. Available from: http://www.ijpmonline.org/text.asp?2009/52/3/353/54992



   Introduction Top


Herpes simplex virus (HSV) infections are among the most common infections worldwide and cause recurrent infections throughout life. Transmission is facilitated by the frequent recurrence of infectious episodes of sub-clinical viral shedding. [1] Moreover, there is increasing evidence that HSV-2 infection could significantly enhance the rates of sexual transmission and acquisition of HIV. [2]

Until recently, the diagnosis of genital herpes was based on typical presentation of genital ulcerations, with or without laboratory confirmation by viral culture. After infection with HSV, specific antibodies are formed against the pathogen, which can be detected by various immunological methods. The test method used and the choice of the pathogen-specific antigen both have a significant bearing on the meaningfulness of such tests. Because it is possible to differentiate between the individual immunoglobulin classes in the enzyme immunoassay, more precise statements about the immunological status of a patient can be made than those which are based on other serological methods (such as the hemagglutination inhibition test or the complement fixation reaction test).

The present study was done to evaluate the serological profile of HSV-2 among patients having sexually transmitted infections (STI) and to determine the utility of detecting HSV-2 IgM in such a high- risk group. Existence of any correlation of HSV- 2 infection with other STI including HIV has also been attempted.


   Materials and Methods Top


Hundred consecutive patients from April 2005 to December 2005, who attended the STI clinic of a tertiary care hospital, with one or more of the complaints as enunciated by WHO in syndromic approach for the diagnosis of STI, were included as subjects. Detailed history, demographical and clinical features were recorded. All the subjects were screened for other common STI by standard laboratory procedures/ commercially available kits. Ten ml blood without anticoagulant was collected aseptically from all patients into screw-capped glass tubes. Sera was separated and stored at -20C. HSV-2 IgM antibody in patient's sera was detected by Ridascreen HSV-2 IgM (K5231, Germany) kit according to the manufacturer's instructions. It is an indirect enzyme immunoassay for semi- quantitative estimation of IgM antibodies against HSV-2 in human serum. HSV-1 IgM antibody was also detected by Meddens Diagnostics Herpes simplex virus IgM capture EIA (REF 4051, Netherlands). It is an antibody class capture immunosorbant assay for the detection of HSV IgM in human serum. Sera were also tested for antibodies of other STI, namely HIV, Hepatitis B virus (HBV) and Hepatitis C virus (HCV) by ELISA and Treponema pallidum by VDRL followed by Treponema pallidum hemagglutination test (TPHA). Antigen detection for Chlamydia trachomatis in genital swab of all the patients was performed by Bio-Rad Chlamydia Microplate EIA (31189 United States) kit.


   Results Top


Out of the total enrolled patients, 30 patients were found to have genital herpes either clinically and/or serologically. Fifteen of them were males and 15 females. The age varied from 14 to 45 years and the majority were in the age group of 25-30 years. History of promiscuity was associated in all male patients and one female patient.

Patients diagnosed as genital herpes (23/30) mainly presented with multiple ulcers over genital area (shaft of penis, prepuce, glans, labia majora, perianal area). The ulcers were well defined, superficial, surrounded by erythematous halo. Some were mildly tender. Few of the ulcers showed discharge (pus/blood) while crust formation was seen in some of them.

As shown in [Table 1], in 17/30 (56.6%) patients, HSV-2 serology was found to correlate with the clinical diagnosis. However, 7/30 (23.33%) HSV-2 IgM seropositive patients had clinical presentation other than genital herpes; 6/30 (20%) had typical presentation of genital herpes and responded to treatment but were found to be seronegative for HSV-2 IgM. While 2/30 patients were seropositive for both IgM HSV-2 and IgM HSV-1 antibody and corroborated with clinical presentation of genital herpes.

The coexistence of other infections in HSV-2 seropositive patients was detected in 8/30 patients as depicted in [Table 2]. None of the concomitant infections had been clinically diagnosed accurately. Most serologically diagnosed were clinically silent infections. Patients having genital herpes co-infected with HIV, had ulcers for longer duration, more tender and necrotic in nature.

The sensitivity and specificity of HSV-2 IgM antibodies was calculated for the diagnosis of genital herpes when compared to that of the clinical diagnosis [Table 3].


   Discussion Top


Viral culture and polymerase chain reaction (PCR) methods are accurate and reliable tests for diagnosing herpes simplex infections when lesions are apparent. However, patients often present when lesions are healed or when lesions are absent. In addition, HSV may fail to grow in the laboratory or the specimen may be inadequate for antigen detection or PCR.

In this situation, a blood sample can be taken for detection of antibodies to HSV. HSV antibody testing can reveal acute infection or previous exposure. HSV type-specific antibody testing is available using Western blot or enzyme immunoassay. Western blot is considered the gold standard in serological testing for HSV antibody but the test is technically difficult, expensive and is only available in a small number of laboratories.

There are now a number of commercially available ELISA tests for detecting type-specific HSV infection. These tests are relatively simple to perform in the laboratory, and are now being produced by a number of companies. Their sensitivity varies depending on the antigen preparation used in the test; most now use recombinant antigens. The most appropriate test for use in particular situations is yet to be determined. Therefore, the present study was done to evaluate the diagnostic utility of detecting HSV-2 IgM by a commercially available kit in STI patients.

IgM antibodies are usually detectable 9-10 days after exposure to the virus and last for 7-14 days, although they may remain detectable for even up to six weeks in certain individuals. [3],[4] Thus it is assumed that if a test discovers IgM, the person has recently acquired herpes. However, research shows that IgM can reappear in blood in up to a third of people during recurrences, while it will be negative in up to half of persons who recently acquired herpes but have culture-documented first episodes. [5] The present study showed that the clinical diagnosis was in congruence with serological evidence for IgM HSV-2 antibody in 56.6% (17/30) while it was incongruent in 43.3% (13/30) patients; 3/17 seropositive patients had recurrent episode of genital ulcer with lower or indeterminate HSV-2 IgM antibody titer, suggesting that HSV-2 IgM may be positive in recurrent episodes of genital herpes but at lower titer. Also 6/30 patients had clinical presentation of genital herpes but were seronegative for HSV-2 IgM suggesting that the patients could be in the late phase of the infection, when IgM HSV-2 is not detectable. Therefore, IgM tests can lead to deceptive test interpretations.

In addition, it is essential to accurately distinguish between HSV-1 and HSV-2 antibodies to prevent false positive result for HSV-2. This is important as most of the adult population in developed countries already have antibodies to HSV-1, which is the primary cause of oral herpes. [5] Though genital herpes can be caused by both HSV-1 and HSV-2, frequent recurrences are more by HSV-2. [6] Glycoprotein G2 (gG2) is a highly specific surface protein for the detection of antibodies against HSV-2. Unlike total surface antigen, which shows partially similar epitopes as HSV-1, known cross-reactions do not occur with antibodies against HSV-1 gG1. But IgM antibodies are mostly directed against surface antigens other than gG2. [7],[8] Since most of the kits for HSV-2 IgM detection including the kit used in our study, use total surface antigen of HSV-2, it was expected that IgM antibodies against HSV-1 could give false positive result in these tests. In our study, 2/30 patients were seropositive for both IgM HSV-1 and HSV-2, suggesting that cross-reaction does occur between them. However, the antibody titer of IgM HSV-2 was much higher compared to IgM HSV-1, indicating HSV-2 infection. This suggests that in our study population HSV-2 is nearly the sole cause of genital herpes and a kit detecting only HSV-2 IgM can be used as a single test for the diagnosis of genital herpes rather than using a combination of tests to detect both HSV-1 and HSV-2 antibodies.

Statistical indices of HSV-2 IgM serology by using commercial ELISA system are indicated in [Table 3]. Indices of the sensitivity and specificity of HSV-2 IgM antibodies for the diagnosis of genital herpes were evaluated and compared with the clinical diagnosis of genital herpes. The specificity was 90.90% and negative predictive value (NPV) 92.90%. However, the sensitivity was only 73.9% and the positive predictive value (PPV) 70.83%. Thus, the test has high specificity and NPV in patients with genital herpes, making it useful as a confirmatory test. Since the sensitivity and PPV is less, this test could not be used as screening test. Therefore within STI clinic populations, it is essential to have knowledge about the expected seroprevalence and possible risk factors and behavior, which may help to determine whether testing will be worthwhile.

Mixed infection with HIV 4/30 (13%) and with HBV 3/30(10%) was a striking observation in this study, a trait observed by other workers also, underpinning the feature of genital ulcer as facilitator in the transmission and enhancing susceptibility to HIV infection by sexual contact. [9],[10] Also, co- infected individuals appeared to be subject to high levels of asymptomatic HSV-2 genital infection, which could increase their genital infectivity for HIV-1 and therefore, the rates of HIV transmission to potentially exposed HIV-1-negative sexual partners. [11] Such a situation could be particularly critical in discordant heterosexual or homosexual couples in which one of the two partners is HIV-1-HSV-2 co-infected while the other is not infected with HIV-1. [2,[12],[13] Thus, it becomes essential to perform periodic, repeated and comprehensive screening of HIV patients for which detection of HSV-2 IgM antibody could be used as a supportive test.

Syndromic approach in large measure provides a pragmatic means of effective intervention. However, there were occasions when this approach was not axiomatic. For example, in this study 8/30 (26%) patients had multiple infections that were difficult to identify clinically alone. Even more importantly, the treatment of these patients covered a single pathogen only, highlighting the inadequacy of the therapeutic coverage. Also 7/30 (23.33%) patients who were seropositive for IgM HSV-2 antibody were incongruent to clinical diagnosis of genital herpes. Thus, while the practicality and field utility of syndromic approach is appreciated, at the same time, one cannot put too fine a point on it; this approach cannot totally extinguish the need for serological diagnosis in the laboratory.

In a nutshell, HSV-2 IgM detection could be used as a supportive test for the diagnosis of genital herpes. But at the same time, this test can also lead to deceptive assumption about when a person actually acquired HSV-2. It needs to be emphasized that the sensitivity and PPV scores are pointers for further improvement in the commercial assay systems and a large sample size may determine the broader utility of such systems.

 
   References Top

1.Sacks SL, Griffiths PD, Corey L, Cohen C, Cunningham A, Dusheiko GM, et al . HSV shedding. Antiviral Res 2004;63 : S19-26.   Back to cited text no. 1  [PUBMED]  [FULLTEXT]
2. Wald A, Corey L. How does herpes simplex virus type 2 influence human immunodeficiency virus infection and pathogenesis? J Infect Dis 2003;187 : 1509-12.  Back to cited text no. 2    
3.Ho DW, Field PR, Irwing WL, Packham DR, Cunningham AL. Detection of immunoglobulin M antibodies to glycoprotein G-2 by western blot (immunodot) for diagnosis of initial herpes simplex genital infections. J Clin Microbiol 1993;31:3157-64.  Back to cited text no. 3    
4.Ho DWT, Field PR, Sjogren-Jansson E, Jeansson S, Cunningham AL. Indirect ELISA for the detection of IgG and IgM antibodies with glycoprotein G (gG2). J Virol Methods 1992;36:249-64.  Back to cited text no. 4    
5.Morrow RA, Brown ZA. Common use of inaccurate antibody assays to identify infection status with herpes simplex virus type 2. Am J Obstet Gynecol 2005;193:361-2.  Back to cited text no. 5  [PUBMED]  [FULLTEXT]
6.Webb DH, Fife KH. Genital Herpes simplex virus infections. Infect Dis Clin North Am 1987;1:97-122.  Back to cited text no. 6  [PUBMED]  
7.Hashido M, Kawana T. Herpes simplex virus-specific IgM, IgA and IgG subclass anti-body responses in primary and non primary genital herpes patients. Microbiol Immunol 1997;41:415-20.  Back to cited text no. 7  [PUBMED]  
8.Juto P, Settergren B. Specific serum IgA, IgG and IgM antibody determination by a modified indirect ELISA-technique in primary and recurrent Herpes simplex virus infection. J Virol Methods 1988;20:45-55.  Back to cited text no. 8  [PUBMED]  [FULLTEXT]
9.Boulos R, Ruff AJ, Nahmias A, Holt F. Herpes simplex virus type 2 infection, syphilis, and hepatitis B virus infection in Haitian women with human immunodeficiency virus type 1 and human T lymphotrophic virus 1 infections. The johns Hopkins University (JHU)/Centre pour le Developpment et la Sante (CDS) HIV study group. J Infect Dis 1992;166:418-20.  Back to cited text no. 9    
10.Sulak PJ. Sexually transmitted diseases. Seminars in reproductive medicine 2003;21:399-413.  Back to cited text no. 10  [PUBMED]  [FULLTEXT]
11.Sacks SL, Griffiths PD, Corey L, Cohen C, Cunningham A, Dusheiko GM, et al . HSV-2 transmission. Antiviral Res 2004;63:S27-35.  Back to cited text no. 11  [PUBMED]  [FULLTEXT]
12.Bujan L, Pasquier C, Labeyrie E, Lanusse-Crousse P, Morucci M, Daudin M. Insemination with isolated and virologically tested spermatozoa is a safe way for human immunodeficiency type 1 virus-serodiscordant couples with an infected male partner to have a child. Fertil Steril 2004;82:857-62.  Back to cited text no. 12  [PUBMED]  [FULLTEXT]
13.Hook EW 3rd, Cannon RO, Nahmias AJ, Lee FF, Campbell CH Jr, Glasser D, et al . Herpes simplex virus infection as a risk factor for human immunodeficiency virus infection in heterosexuals. J Infect Dis 1992;165:251-5.  Back to cited text no. 13  [PUBMED]  

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Correspondence Address:
Shilpee Choudhry
Department of Microbiology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi - 110 095
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0377-4929.54992

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    Tables

  [Table 1], [Table 2], [Table 3]

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