IgG antibodies to herpes simplex virus 2 (HSV-2)
Herpes simplex virus type 2 (HSV-2) is a contagious and lifelong persistent infection that is mainly associated with genital herpes. The primary route of transmission of the virus is sexual contact, but infection can also occur via direct contact with mucous membranes or damaged skin. By analyzing IgG antibodies in the blood, a previous HSV-2 infection can be detected, which provides valuable information when investigating symptoms, risk of infection and future treatment strategies.
Indications for IgG analysis in HSV-2
There are several clinical situations in which an analysis of HSV-2-specific IgG antibodies is of importance. Since these antibodies are formed after a primary infection and persist in the circulation for a long time, the test can confirm previous exposure even in asymptomatic cases. Indications for testing include:
- Recurrent genital symptoms: In case of repeated episodes of ulcers, blisters or irritation in the genital area.
- Before pregnancy: HSV-2 can rarely cause neonatal complications, which is why testing may be indicated.
- In case of concern after unprotected contact: Determine possible previous exposure in case of uncertain sexual history.
- Infection investigation: In case of unclear ulcers or symptoms where herpes infection is a possible differential diagnosis.
Pathogenesis and symptoms of HSV-2 infection
HSV-2 initially infects epithelial cells at the time of infection and then spreads retrogradely along sensory nerve pathways to the dorsal ganglia of the lumbar spine, where it establishes a lifelong latency. Viral reactivation can be triggered by factors such as stress, immunosuppression, infections or hormonal changes.
The clinical symptoms vary depending on the phase and extent of the infection:
- Primary infection: Often symptomatic with painful blisters, fever, headache and lymphadenopathy.
- Reactivation: Recurrent blisters, often on the same skin area, as well as burning, itching and discomfort during urination.
- Asymptomatic infection: Common, especially in women, which makes serological testing crucial in tracing infection.
Factors that can affect the test result
It usually takes 2–12 weeks for IgG antibodies to be detected after a primary infection, but in some cases the process can take up to six months. Therefore, a negative test result in the presence of suspicion of recent infection may require follow-up testing. Factors that may affect the result include:
- Time of test: Early in the course, IgG antibodies may be absent despite ongoing infection.
- Immune system status: A compromised immune system may delay or weaken the antibody response.
- Laboratory method: Different test methods have varying sensitivity and specificity.
Interpretation of results
- Positive IgG result: Indicates previous HSV-2 infection. The antibodies usually persist for life and are a sign of previous exposure to the virus, regardless of the symptom picture.
- Negative IgG result: No antibodies have been detected, which speaks against previous infection. However, in the case of ongoing symptoms, it may be relevant to consider new testing after a few months.
Clinical relevance of HSV-2 IgG analysis
Analyzing IgG antibodies to HSV-2 is of great clinical importance in cases of suspicion of genital herpes and for preventive purposes, for example during pregnancy or before planned procedures where immune status is relevant. The test provides information about previous infection and can be a guide in the differential diagnosis of genital ulcers and in counseling about the spread of infection and treatment.