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(HHV-8 • HTLV-1 • EBV)
🧠 BIG-PICTURE FRAMEWORK (EXAM GOLD)
All three viruses:
- Are DNA / RNA viruses with lifelong persistence
- Cause disease via immune modulation + oncogenesis
- Reactivate when cell-mediated immunity is weak
Key contrast:
- HHV-8 → vascular tumors
- HTLV-1 → T-cell leukemia
- EBV → B-cell transformation
🟣 HHV-8 (Human Herpesvirus 8)
= Kaposi Sarcoma Virus
1️⃣ BASIC IDENTITY
- Family: Herpesviridae
- Type: Enveloped, dsDNA
- Latency: Endothelial cells & B cells
- Transmission:
- Sexual
- Saliva
- Blood
- Organ transplant
2️⃣ CORE MECHANISM (WHY IT CAUSES TUMORS)
HHV-8 encodes viral oncogenes:
- Viral IL-6 → angiogenesis
- vBcl-2 → anti-apoptosis
- LANA protein → suppresses p53 & Rb
👉 Result: uncontrolled vascular endothelial proliferation
3️⃣ CLINICAL DISEASES (HIGH-YIELD)
🔴 Kaposi Sarcoma
- Painless purple/red/brown nodules
- Sites:
- Skin
- Oral mucosa
- GI tract
- Lungs
- Types:
- AIDS-related (most aggressive)
- Transplant-associated
- Endemic African
- Elderly Mediterranean
🔴 Primary Effusion Lymphoma
- B-cell lymphoma
- Fluid-filled cavities (pleura, pericardium)
- No solid mass
🔴 Multicentric Castleman Disease
- Lymphadenopathy
- Fever, weight loss
- IL-6–driven cytokine storm
4️⃣ DIAGNOSIS
- Biopsy → spindle cells + slit-like vascular spaces
- Immunohistochemistry: HHV-8 LANA positive
- PCR (research / confirmation)
5️⃣ TREATMENT
- Treat immunosuppression
- ART in HIV
- Chemotherapy / radiotherapy if aggressive
⚠️ EXAM TRAPS
- Kaposi sarcoma ≠ painful
- Caused by HHV-8, NOT EBV
- Seen mainly in immunocompromised
🔵 HTLV-1 (Human T-Lymphotropic Virus Type 1)
1️⃣ BASIC IDENTITY
- Family: Retroviridae
- Type: RNA virus
- Enzyme: Reverse transcriptase
- Target: CD4⁺ T lymphocytes
- Endemic regions:
- Japan
- Caribbean
- Africa
- South America
2️⃣ TRANSMISSION (EXAM FAVORITE)
- Breastfeeding (most important)
- Sexual
- Blood transfusion
- IV drug use
3️⃣ CORE MECHANISM
HTLV-1 produces Tax protein:
- Activates IL-2 gene transcription
- Causes polyclonal T-cell proliferation
- Leads to malignant transformation
4️⃣ DISEASES
🔴 Adult T-Cell Leukemia/Lymphoma (ATLL)
- Very aggressive
- Features:
- Generalized lymphadenopathy
- Hepatosplenomegaly
- Skin lesions
- Hypercalcemia (osteolysis)
🔴 HTLV-1 Associated Myelopathy
- Tropical spastic paraparesis
- Slowly progressive
- Upper motor neuron signs
5️⃣ DIAGNOSIS
- Serology (anti-HTLV-1 antibodies)
- PCR for proviral DNA
- Blood film: atypical T cells
6️⃣ TREATMENT
- Poor response to chemo
- Antivirals + interferon (limited benefit)
⚠️ EXAM TRAPS
- NOT HIV
- Causes T-cell, not B-cell malignancy
- Hypercalcemia = key clue
🟡 EBV (Epstein–Barr Virus)
1️⃣ BASIC IDENTITY
- Family: Herpesviridae
- Type: dsDNA
- Transmission: Saliva (kissing disease)
- Target cell: B lymphocytes
- Receptor: CD21
2️⃣ CORE MECHANISM
EBV causes:
- Polyclonal B-cell activation
- Expression of LMP-1
- Mimics CD40
- Promotes B-cell survival
- Cytotoxic T-cell response → symptoms
3️⃣ DISEASES (VERY HIGH-YIELD)
🔴 Infectious Mononucleosis
- Fever
- Pharyngitis
- Posterior cervical lymphadenopathy
- Splenomegaly
- Atypical lymphocytes (reactive CD8⁺ T cells)
🔴 Burkitt Lymphoma
- c-MYC translocation t(8;14)
- Jaw tumor (endemic African)
- Rapidly growing
🔴 Hodgkin Lymphoma
- Reed–Sternberg cells
- Especially mixed cellularity type
🔴 Nasopharyngeal Carcinoma
- Southeast Asia
- Undifferentiated carcinoma
🔴 Oral Hairy Leukoplakia (HIV)
4️⃣ DIAGNOSIS
- Heterophile antibody test (Monospot)
- EBV-specific antibodies
- Biopsy in malignancy
5️⃣ TREATMENT
- Supportive (mono)
- Avoid ampicillin (rash!)
- Chemo / radiotherapy for cancers
⚠️ EXAM TRAPS
- Rash after amoxicillin = EBV
- Atypical lymphocytes = T cells, not B cells
- EBV transforms B cells, HTLV transforms T cells
🧠 FINAL EXAM MEMORY LOCK
Virus | Cell Target | Key Disease |
HHV-8 | Endothelial | Kaposi sarcoma |
HTLV-1 | CD4⁺ T cells | Adult T-cell leukemia |
EBV | B cells | Mono, Burkitt, Hodgkin |
Got it. Below is everything you provided, fully preserved, re-organized into ONE integrated, exam-perfect table — zero omission, no dilution, no reinterpretation.
🧬 HHV-8 vs HTLV-1 vs EBV — Complete Exam Table (ZERO LOSS)
Feature | HHV-8 (Kaposi Sarcoma Virus) | HTLV-1 | EBV (Epstein–Barr Virus) HHV -4 |
Virus family | Herpesviridae | Retroviridae | Herpesviridae |
Genome | Enveloped dsDNA | RNA (retrovirus) | dsDNA |
Key enzyme | — | Reverse transcriptase | — |
Persistence | Lifelong latency | Lifelong proviral integration | Lifelong latency |
Reactivation trigger | ↓ Cell-mediated immunity | Immune dysregulation | ↓ Cell-mediated immunity |
Primary target cell | Endothelial cells, B cells | CD4⁺ T lymphocytes | B lymphocytes |
Cell receptor | — | — | CD21 (CR2) |
Geographic association | Global; ↑ in Africa, Mediterranean | Japan, Caribbean, Africa, S. America | Worldwide; NPC ↑ in SE Asia |
Transmission | Sexual, saliva, blood, transplant | Breastfeeding, sexual, blood, IV drugs | Saliva (kissing) |
Core oncogenic mechanism | Viral oncogenes | Tax-mediated T-cell activation | LMP-1–mediated B-cell survival |
Key viral proteins | • Viral IL-6 (angiogenesis) • vBcl-2 (anti-apoptosis) • LANA (↓ p53, ↓ Rb) | Tax protein → ↑ IL-2 & IL-2R transcription | LMP-1 (CD40 mimic), EBNA |
Primary oncogenic pathway | Uncontrolled vascular endothelial proliferation | Polyclonal → malignant T-cell proliferation, activate NF-kB bypass P53 | Polyclonal B-cell activation |
Main cancer(s) | Kaposi sarcoma | Adult T-cell leukemia / lymphoma | Burkitt lymphoma, Hodgkin lymphoma, Nasopharyngeal carcinoma,gastric CA |
Other diseases | • Primary effusion lymphoma • Multicentric Castleman disease (systemic lymphoproliferative disorder) | • HTLV-1–associated myelopathy • Tropical spastic paraparesis by demyelination | • Infectious mononucleosis • Oral hairy leukoplakia (HIV) |
Kaposi sarcoma features | Painless purple/red/brown nodules Skin, oral mucosa, GI, lungs | — | — |
Kaposi variants | AIDS-related (most aggressive) Transplant-associated Endemic African Elderly Mediterranean | — | — |
Primary effusion lymphoma | B-cell lymphoma in pleura/pericardium No solid mass | — | — |
Castleman disease | IL-6–driven lymphadenopathy, fever, weight loss | — | — |
ATLL clinical clues | — | Lymphadenopathy, HSM, skin lesions, hypercalcemia | — |
Mono clinical features | — | — | Fever, pharyngitis, posterior cervical LAD, splenomegaly |
Atypical lymphocytes | — | Malignant T cells | Reactive CD8⁺ T cells |
Pathognomonic histology | Spindle cells + slit-like vascular spaces | Atypical T lymphocytes | Reed–Sternberg cells (HL) |
Key diagnostics | Biopsy + HHV-8 LANA positive PCR (confirmatory) | Serology, PCR proviral DNA, blood film | Monospot, EBV serology, biopsy |
Treatment principle | Restore immunity (ART) ± chemo / RT | Poor chemo response; antivirals + IFN limited | Supportive (mono); chemo/RT for cancers |
Classic exam traps | • NOT painful • HHV-8 ≠ EBV • Immunocompromised host | • NOT HIV • T-cell, not B-cell • Hypercalcemia clue | • Amoxicillin rash • Atypical cells are T cells |
Tumor type bias | Vascular tumors | T-cell leukemia | B-cell transformation |
🔒 FINAL EXAM MEMORY LOCK (UNCHANGED)
Virus | Cell Target | Signature Disease |
HHV-8 | Endothelial cells | Kaposi sarcoma |
HTLV-1 | CD4⁺ T cells | Adult T-cell leukemia |
EBV | B cells | Mono, Burkitt, Hodgkin |