6. Pathogenesis: Words to remember
Primary receptor for HIV
Secondary receptor or
co-receptors
CD4
CXCR4 and CCR5
Dendritic cells Key role in transmission of HIV
to draining lymph nodes
where viral replication takes place.
Sequence of
HIV enzymes
1. Reverse transcriptase
2. Integrase
3. Protease
7. HIV evades the immune response during
Primary HIV infection
• Target on CD4 T cells and macrophages (both
innate and adaptive immunity)
• Latency (resting latently in infected cells)
• Massive loss of HIV-1 specific CD4 T cells
• Lack of CD4 impairs cytotoxic T cells.
• Viral evolution (highly mutant)
Chronic HIV infection
8. Test: A1, A2, A3
คือ ชุดทดสอบที่แตกต่างกัน
(การตรวจ Ab ด้วยเทคนิคที่แตกต่างกัน
การตรวจ Ag โดยบริษัทที่ต่างกัน)
โดย A1 มีความไวมากกว่า A2, A3
(มากกว่าร้อยละ 99.0)
*ไม่จาเป็นต้องตรวจ Western blot
แนวทางการตรวจวินิจฉัย
National guideline: Thailand 2010
9. การตรวจวินิจฉัยการติดเชื้อเอชไอวีในประเทศไทย
• การตรวจหาส่วนประกอบของไวรัส
– Viral protein: นิยมตรวจหาส่วนของ p24 Ag ระดับในกระแสเลือดอาจมีการเปลี่ยนแปลงขึ้นลงได้ใน
เวลาที่ต่างกัน การตรวจหา p24 Ag ใช้เพื่อวินิจฉัยการติดเชื้อเอชไอวีในระยะเริ่มแรกซึ่งตรวจพบได้ก่อน
ตรวจพบ antibody อย่างน้อย 5 วัน
– Nucleic acid Amplification Test (NAAT): เป็นการตรวจ RNA ชนิดที่มีการรายงานผลเป็น
บวกหรือลบ (positive or negative)
• วิธีการตรวจหา antibody ต่อเชื้อเอชไอวี ได้แก่
– Enzyme-linked immunosorbent assay (ELISA): HIV antigen ถูกตรึงบน solid
phase อ่านผลปฏิกิริยาระหว่าง antigen กับ antibody โดยดูการเปลี่ยนแปลงที่เกิดขึ้นซึ่งเกิดจาก
เอนไซม์ย่อย substrate และวัดการเปลี่ยนแปลงนั้นด้วยเครื่องอ่าน
– Agglutination: HIV antigen ถูกเคลือบบนผิวของอนุภาค อ่านผลโดยดูการเกาะกลุ่มวิธีนี้เป็นวิธีที่
ปฏิบัติได้ง่าย (simple test)
– Dot/ line immunoassay: HIV antigen ถูกตรึงบนผิวของ solid phase ในลักษณะเป็นจุด
(dot) หรือ เส้น (line) อ่านผลของปฏิกิริยาโดยดูสีที่เกิดขึ้น ได้ผลรวดเร็ว (rapid test)
National guideline: Thailand 2010
22. How should screening for aneuploidy be undertaken?
• HIV infection and/or HAART - biochemical markers
– Second-trimester screening for Down syndrome:
Elevated hCG, AFP1,2 was associated with high viral
loads and low CD4 cell counts2
• Brossard et al (2008)3 - Case–control study of 312 HIV
infected women
– MOMs for PAPP-A and beta-hCG: lower in HIV-positive
women (0.88 vs 1.05 and 0.84 vs 1.09, respectively;
P<0.005)
– No differences – Fetal NT, alpha fetoprotein (2nd
trimester)
– No impact on risk estimation of risk of Down syndrome
1 Yudin MH, et al. AJOG 2003; 189: 973–6
2 Gross S, et al. AJOG 2003; 188: 1052–6
3 Brossard P, et al. AIDS 2008; 22: 2013–7
23. How should screening for aneuploidy be undertaken?
• Savvidou (2010): Case control study: 90 HIV-positive and
450 HIV-negative pregnant women, 1st trimester markers
Savvidou et al. BJOG. 2010; 117: 1-5
Parameter HIV neg
(n = 450)
HIV pos
(n = 90)
P value HIV untreated
(n=49)
HIV treated
(n=41)
P value
Delta NT 0.07
(-0.10 to 0.31)
0.05
(-0.14 to 0.25)
0.14 -0.05
(-0.22 to 0.17)
0.07
(-0.13 to 0.31)
0.16
Free beta
hCG(MoM)
1.00
(0.68–1.47)
0.93
(0.61–1.45)
0.29 1.03
(0.76–1.85)
0.74
(0.45–1.32)
0.006
PAPP-A
(MoM)
1.00
(0.69–1.42)
0.94
(0.65–1.59)
0.89 1.05
(0.64–1.66)
0.89
(0.66–1.47)
0.41
No statistically significant differences in the levels of free beta-hCG, PAPP-A
and fetal NT
24. How should screening for aneuploidy be undertaken?
• Spencer (2010) – Case-control study
• 1st trimester: 92 HIV-infected women VS 912 controls
– No significant difference
– Free Beta-hCG MoM level (0.978 vs. 0.981, p = 1.0)
– PAPP-A MoM levels (1.190 vs. 1.102, p = 0.099)
– Delta NT (0.1374 vs. 0.0445, p = 0.063)
Spencer K. et al. Fetal Diagn Ther. 2010; 24: 1-4
25. How should screening for aneuploidy be undertaken?
• Spencer (2010) – Case-control study
• 2nd trimester: 52 HIV-infected women VS 378 controls
– No significant difference: hCG (1.0575 vs. 0.9619, p =
0.18), AFP (0.9734 vs. 0.9350, p = 0.65)
– UE3: significantly lower (0.970 vs. 1.110, p = 0.0005)
– Further studies are required to evaluate UE3 levels
and impact on screening in the second trimester
Screening for aneuploidy can be offered to
pregnant women who are HIV positive
Spencer K. et al. Fetal Diagn Ther. 2010; 24: 1-4
26. How safe is invasive diagnostic testing?
• Pre-HAART era - increased risk of HIV transmission (2-4
fold)
• HAART era – limited data
• Somigliana (2005) - multicenter case series: 63 HIV
infected women underwent amniocentesis(89%), CVS or
cordocentesis: 1st-2nd trimester
– 2 of 60 viable infants (3.3%) were infected with HIV
– No significant difference observed in women who did
not undergo antenatal invasive techniques (1.7%, P =
0.30)
– No transmissions occurred among 45 women on
combination antiretroviral drug regimens
Somigliana E, et al. AJOG 2005; 193: 437–42
27. • Mandelbrot (2009) - Multicenter French Perinatal HIV
Cohort (1985 – 2006) - 142 amniocenteses / 9302
singleton pregnancies
– MTCT in the amniocentesis group
• mothers who received no antiretroviral agents –
3/12 (25.0%)
• mothers receiving monotherapy or double-NRTI -
3/49 (6.1%)
• mothers receiving HAART (0/81) VS 1.2%
(30/2,528) when no amniocentesis was performed
– Conclusion: Amniocentesis is not a major risk factor
for MTCT in mothers treated with effective
antiretroviral therapy
How safe is invasive diagnostic testing?
Mandelbrot L, et al. AJOG 2009;200:160.e1-160.e9
28. • For women known to be HIV positive
– Taking HAART, viral load > 50 copies/ml - advisable
to delay the amniocentesis until the maternal viral
load < 50 copies/ml or undetectable
– Not already taking HAART, administration of
antiretrovirals to cover the procedure is advised
– When performing amniocentesis, the placental route
is absolutely contraindicated
– CVS and cordocentesis - too risky to offer to HIV-
infected women
How safe is invasive diagnostic testing?
RCOG, green top guidelines No 39. July 2010
Recommendations for Use of Antiretroviral Drugs in Pregnant HIV-1-Infected Women, USA 2010
29. When should ultrasound scanning be undertaken?
• Antiretroviral drugs and congenital anomalies –
No significant association
– Townsend (2009)1 – UK national surveillance study,
N=8,242
• Rate of reported major and minor congenital
abnormality - 2.8%
• No increased risk of abnormalities in infants exposed
to efavirenz (2.4%)
– NICHD International Site Development Initiative (NISDI)
study(2010)2
• Overall prevalence of congenital anomaly - 6.2/100 live
births
• 1st trimester exposure - similar to 2nd or 3rd trimester
exposure 1 Townsend C, et al. AIDS 2009, 23:519–524
2 Joao EC,et al. J Acquir Immune Defic Syndr 2010; 53: 176–85
30. What are the complications of HIV and adverse effects
of HAART? - prior to antiretroviral use
• Brocklehurst (1998) - meta-analysis; 31 prospective
studies(1983 -1996)
– Spontaneous abortion 4.05 (95% CI 2.75-5.96)
– Stillbirth 3.91 (95% CI 2.65-5.77)
– Perinatal mortality 1.79 (95% CI 1.14-2.81)
– IUGR 1.70 (95% CI 1.43-2.02)
– Low birthweight 2.09 (95% CI 1.86-2.35)
– Preterm delivery 1.83 (95% CI 1.63-2.06)
• More advanced disease and/or immunosuppression -
higher rates of adverse outcomes
Brocklehurst P, et al. BJOG. 1998;105:836-48
31. • Neonatal outcome of premature deliveries VS the
increased risk of perinatal transmission
• PPROM - GA > 34 weeks
– The risk of chorioamnionitis and perinatal HIV
transmission should be concerned
– Delivery should be expedited
• PPROM – GA < 34 weeks
– Limited case series data regarding transmission risk
in women taking HAART
How should preterm PROM be managed?
32. Duration of membranes rupture
• Meta-analysis of 15 observational studies (4721 HIV-
positive patients)*
– 2% increase in the risk of transmission for each hour
of rupture of membranes (AIDs)
– Non-AIDs, 6% at 2 hours and 8% at 24 hours
AIDs
Non-AIDs
Herpes Simplex and HIV infections and Preterm PROM. 2011; 54(2): 330-6
33. • PPROM – GA < 34 weeks
– No clear guidelines for the management
– Multidisciplinary team consultation – HIV physicians
and pediatricians
– Antenatal corticosteroids
– Genital infection screening
– Antibiotics for prolonged latency period
– Evidence of chorioamnionitis and fetal distress -
prompt delivery
How should preterm PROM be managed?
RCOG, green top guidelines No 39. July 2010
Panel on treatment of HIV-infected pregnant women and
prevention of perinatal Transmission, NIH, USA, 2010