Dynamic changes of HIV antibody detection in an early stage of HIV infection

AIDS window period (WindowPeriod): The period from when HIV enters the human body to the time when a sufficient amount of HIV antibodies can be detected in the blood is called the window period
.

With the continuous development of AIDS testing technology, the window period can be shortened to 14-21 days

Case history

Case history

The patient, male, 20 years old, was admitted to the First Affiliated Hospital of Dalian Medical University on August 27, 2016 with "fever for more than 20 days, aggravated cough and sputum for 4 days"
.

More than 20 days ago, the patient had fever without obvious cause.

The cough is intermittent, and the sputum is white and sticky.
For diagnosis and treatment, I went to the 5th People’s Hospital.
After completing the relevant examinations, it is recommended that the patient be transferred to our hospital for treatment
.

Past history: past 4 months of sinusitis, denying history of hepatitis, tuberculosis, malaria, intermittent smoking for 3 years, denying history of family genetic diseases and infectious diseases

Admission examination: body temperature 37.
9℃, heart rate 84 beats/min, breathing 22 beats/min, blood pressure 120/80mmHg
.

Consciousness, lethargy, basic physical examination, no yellow stains and bleeding on the skin all over the body, no swelling of lymph nodes, no obvious abnormalities in the head, slightly thicker breath sounds in both lungs, no other murmurs and pleural friction sounds in the lungs , Li Qi

Emergency examination: (1) Blood cell analysis: white blood cell 19.
38×10^9/L, neutrophil ratio 22.
8%, lymphocyte ratio 67.
70%
.

(2) Biochemical: ALT145U/L, AST189U/L, CK42IU/L, Na136mmol/L, white ball ratio 1.
07
.

(3) Mycoplasma pneumoniae antibody is positive

(4) Chest CT: There is no obvious abnormality in the chest, and the spleen is enlarged
.

Preliminary diagnosis: (1) Fever to be checked (the possibility of mycoplasma pneumonia is high); (2) Splenomegaly to be checked; (3) Acute liver damage; (4) Electrolyte imbalance and hyponatremia
.

Diagnosis and treatment plan: The patient has a high possibility of mycoplasma infection, but at the same time, the virus infection cannot be ruled out.

case analysis

case analysis

1.
Simple lung infection cannot be explained, clinically suspected

The patient's blood test showed that the white blood cells were significantly increased, suggesting the presence of infection
.

But at the same time, the patient has a long fever, the site of infection is not clear, and there is an enlarged spleen, low neutrophils, and elevated lymphocytes and monocytes.

The laboratory reported that the HIV antibody was reactive, and the corresponding treatment and diagnosis and treatment opinions were given as soon as possible in the clinic: the patient's white blood cells were significantly increased, so active anti-infection treatment was given
.

Patients with abnormal liver function should be treated with hepatoprotective and symptomatic treatment

2.
The laboratory is actively investigating, tracking and testing

Immune room serum test result: HIV antibody anergy (3rd generation A manufacturer) on August 28, because this patient is clinically suspected of having acquired immunodeficiency syndrome, and epidemiological investigations have admitted that there has been male-to-male sex
.

The laboratory used the third-generation B manufacturer to re-test, the result was reactive, and the latex method was positive

Table 1 Tracking test results

Table 1 Tracking test results Table 1 Tracking test results

Blood was collected again on September 4, and the HIV antibody screening test was positive
.
The confirmed result is only two specific bands gp160 and p24.
The report of HIV antibody is uncertain, and it is recommended to review it in half a month
.
This specimen was subjected to a quantitative nucleic acid detection of 1.
45×106IU/mL, and the result was positive
.

Table 2 Application of the fourth-generation reagent to track the retest results

Table 2 Application of fourth-generation reagents to track re-examination results Table 2 Application of fourth-generation reagents to track re-examination results

The results in Table 1 show that the screening results in early August are one yin and one yang, the confirmed result in September is indeterminate for HIV antibodies, the nucleic acid test result in September is positive, and the confirmed result in October has 3 bands.
Based on this, the case is inferred.
Early HIV infection [1], HIV "window period" cases
.
The main reason for the positive initial screening test and the uncertain result of the confirmatory test is early HIV infection or non-specific reaction
.
In this case, as the disease progressed, the HIV antibody detection gradually increased, and the WB band type also showed a progressive change.
By November, the three band types were detected in the confirmation test, and this case was finally confirmed to be HIV antibody positive
.

Knowledge development

Knowledge development

At present, the most commonly used detection methods for HIV antibody detection in China include enzyme-linked immunosorbent assay, rapid detection, and western blot test (WB)
.
These detection methods have their own advantages and disadvantages.
Due to their different sensitivities, the reagent detection "window period" is different, and it is easy to cause missed detection
.

In response to the negative result of the initial screening test of manufacturer A in this case in August, the S/CO value of 0.
28 was light yellow
.
According to the "National AIDS Testing Technical Specifications" "Antibody Screening Test Procedures Using Antibody Test Reagents" Reagent 1 does not respond, and HIV antibody negative should be reported
.

However, considering clinically suspected viral infection, I immediately used the B manufacturer's kit to conduct a recheck experiment.
The S/CO value of 7.
738 reported that the HIV antibody was reactive, and the latex method was used to recheck the reactivity
.
The test results of the reagents of the two manufacturers are inconsistent.
Excluding the error of the experimental operation process, the repeated test results of the two manufacturers are respectively that the S/CO value of the A manufacturer is 0.
46, which is light yellow, and the HIV antibody is still negative according to the judgment standard
.
According to the judgment standard, the S/CO value of B manufacturer was 6.
338, and the antibody was still reactive
.

Analyze the reason: As the antigen composition, production process, and determination criteria of the primary screening reagents produced by different manufacturers may be different, the sensitivity and specificity of the reagents will be different, which may cause differences in the detection results
.
This article traces and compares the preliminary screening results of the third-generation A manufacturer and the third-generation B manufacturer.
The S/CO value of the former is lower than the latter.
This may be related to the variety of antigen coatings, but the purity is relatively low, so it is relatively sensitive.
Low sex is related
.

The author used the fourth-generation HIV antibody reagent and the chemiluminescence antigen-antibody combined detection reagent to do the corresponding follow-up re-examination experiments on the specimens.
The test results shown in Table 2 are all reactive
.
Because of its superior sensitivity to the third-generation HIV antibody reagents, the fourth-generation reagent has the advantage of combined detection of antigen and antibody.
Compared with simple antibody detection, the "window period" can be shortened by about 5-7 days
.

Summary

Summary

Samples with high clinical suspicion are not easily reported negative, and it is necessary to communicate with the clinic in time to understand the medical history, clinical manifestations, and epidemiological investigation results, and use different manufacturers' reagents and different methodological reagents for re-examination
.
No matter which method is reactive in the initial screening, it must be further confirmed by Western blotting or nucleic acid detection
.
It is recommended that qualified laboratories use nucleic acid testing as early as possible to carry out confirmation tests to diagnose and treat patients early
.

This laboratory will use the fourth-generation chemiluminescence detection reagents for preliminary screening experiments in accordance with the "National AIDS Testing Technical Specifications", and then use the fourth-generation reagents of another manufacturer for antibody detection retests
.
In the end, the reactive cases were initially screened and sent to the Center for Disease Control and Prevention for confirmation experiments
.
This method can screen out P24 antigen-positive patients earlier, shorten the window period, and facilitate early screening and diagnosis
.
This report is only a case, and the difference between the preliminary screening reagents and the difference in the detection process needs to be further comprehensively evaluated
.

Expert Reviews

Expert Reviews

The article reports a case of early HIV infection
.
It is suggested that the HIV preliminary screening laboratory does not easily report negative test results for clinically suspicious samples, and should communicate with the clinic in time to understand the medical history, and use different manufacturers' reagents and different methodological reagents for re-examination
.

Reviewer: Zhu Hong, Department of Laboratory Medicine, The First Affiliated Hospital of Dalian Medical University

Comment expert: Zhu Hong, Department of Laboratory Medicine, First Affiliated Hospital of Dalian Medical University, leave a message here