Lung Transplantation

Slide 1 · Lung transplantation

Indications • infection • rejection • pathology

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Identify major indications and understand the choice of single versus bilateral transplantation.

Differentiate infection from rejection using timing, clinical presentation, and pathology.

Recognize the morphological patterns of acute and chronic rejection.

Explain why bronchiolitis obliterans causes irreversible allograft dysfunction.

Slide 3 · Lung transplantation restores gas-exchange capacity

Transplantation replaces one or both severely diseased recipient lungs with donor allograft tissue.

It is considered for terminal, nonneoplastic pulmonary disease.

The graft is functionally valuable but immunologically nonself: Rejection and infection dominate long-term care.

Slide 4 · Eligibility depends on more than lung severity

The underlying pulmonary condition should be advanced and nonneoplastic.

Other serious illness may preclude the lifelong immunosuppression that transplantation requires.

Recipient assessment therefore balances pulmonary benefit against systemic treatment burden.

Slide 5 · Four common transplant indications

End-stage COPD

Idiopathic pulmonary fibrosis

Cystic fibrosis

Idiopathic / familial PAH

Indications listed; Not a ranked frequency comparison.

Slide 6 · End-stage COPD: Loss of functional reserve

Severe COPD is a common indication for lung transplantation in the source.

Obstructive physiology and destructive parenchymal disease limit ventilatory reserve.

The transplant decision concerns the overall severity of established lung disease, not an isolated histologic sign.

Slide 7 · Idiopathic pulmonary fibrosis: Progressive restriction

Idiopathic pulmonary fibrosis is among the major transplant indications.

Fibrosis progressively alters lung architecture and compromises respiratory function.

Transplantation addresses the organ-level consequence rather than reversing fibrosis in the native lung.

Slide 8 · Cystic fibrosis: Structural disease and infection

Cystic fibrosis is a major indication in patients with terminal pulmonary disease.

Chronic suppurative airway disease creates an infectious reservoir in the recipient lungs.

This has a direct surgical implication: Both infected lungs require replacement.

Slide 9 · Pulmonary arterial hypertension as an indication

Idiopathic or familial pulmonary arterial hypertension is explicitly listed as an indication.

The primary physiological burden is pulmonary vascular disease.

The correct operation depends on overall cardiopulmonary assessment; The source does not provide a selection algorithm.

Slide 10 · Single versus bilateral transplantation

Single lung

One donor may benefit two different recipients.

A strategy with a donor-organ allocation advantage.

Bilateral lungs

Associated with better outcomes in the source.

Needed when the native lungs contain bilateral chronic infection.

Slide 11 · Why bilateral infection changes the operation

Bilateral chronic infection

Native lung remains if single graft

Persistent infectious reservoir

Replace both recipient lungs

Illustrative rationale from the cystic fibrosis / bronchiectasis examples.

Slide 12 · The donor-allocation trade-off

Single-lung transplantation can use lungs from one donor to treat two recipients.

Bilateral transplantation provides both donor lungs to one recipient.

The textbook associates bilateral transplantation with superior recipient outcomes, but does not quantify the effect.

Slide 13 · Early surgical and graft complications

Anastomotic / vascular

Anastomotic dehiscence

Vascular thrombosis

Immediate graft dysfunction

Primary graft dysfunction

The source notes improvement with surgical and preservation techniques.

Slide 14 · Two major threats to the lung allograft

Lung allograft

Infection under immunosuppression

Immune rejection of donor tissue

Potential graft dysfunction

Infection and rejection may produce overlapping symptoms; Neither can be inferred from symptoms alone.

Slide 15 · The immunosuppression paradox

Desired effect

Suppress alloreactive lymphocytes.

Reduce tissue-damaging graft immune responses.

Consequent vulnerability

Reduced defenses against pathogens.

Opportunistic pulmonary infections become important.

Slide 16 · Infections resemble those of other immunocompromised hosts

Transplant immunosuppression expands the range of potential pulmonary pathogens.

Usual respiratory pathogens remain important alongside opportunistic agents.

More than one infectious organism may contribute to an infiltrate.

Slide 17 · Infection risk is time-dependent

First few weeks

Bacteria predominate

Weeks to months

Acute rejection often emerges

Months 3–12

Many infections occur

Years later

Rejection and chronic injury remain possible

Approximate textbook periods; Patterns overlap and are not exclusive.

Slide 18 · Early infections: Bacterial predominance

Bacterial infections are the most common infectious events in the first weeks after transplantation.

This timing is a useful prior probability, not a microbiologic diagnosis.

Clinical and imaging manifestations still require evaluation for alternative causes.

Slide 19 · Most infections arise during months 3–12

Most post-transplant infections in the third through twelfth months.

Both conventional and opportunistic organisms remain relevant.

Timing should guide the differential without excluding infection outside this window.

Slide 20 · Bacterial spectrum in immunocompromised lungs

Examples listed in the parent section

Pseudomonas aeruginosa

Mycobacterium species

Additional examples

Legionella pneumophila

Listeria monocytogenes

Slide 21 · CMV pneumonia after transplantation

Cytomegalovirus is an opportunistic viral pneumonia relevant to transplant recipients.

Lower frequency and severity with antiviral prophylaxis and donor–recipient CMV-status matching.

Antiviral-resistant CMV strains are nevertheless described.

Slide 22 · CMV prevention is not elimination

Donor / recipient CMV assessment

Ganciclovir prophylaxis

Lower CMV pneumonia burden

Residual risk: Resistance

Source describes a reduction in frequency/severity, not complete prevention.

Slide 23 · Pneumocystis jirovecii pneumonia

P. Jirovecii is a major opportunistic pneumonia pathogen in immunocompromised hosts.

Post-lung-transplant pneumonia due to this organism as rare with routine prophylaxis.

The usual prophylactic agent named is trimethoprim–sulfamethoxazole.

Slide 24 · The prophylaxis–incidence relationship

High baseline susceptibility

Routine prophylaxis

Reduced P. Jirovecii pneumonia

Remain alert to pulmonary infiltrates

Qualitative conceptual relationship; No incidence values are implied.

Slide 25 · Fungal disease: Aspergillus

Aspergillus species are among the major fungi implicated in post-transplant lung infection.

Infection can involve the lung parenchyma and/or bronchial anastomotic site.

The affected site matters when correlating imaging and bronchoscopic findings.

Slide 26 · Fungal disease: Candida

Candida species are also listed among fungal pathogens after lung transplantation.

Potential sites include the bronchial anastomosis and/or transplanted lung.

The excerpt does not provide microbiologic diagnostic criteria; Organism recovery alone should not be overinterpreted.

Slide 27 · The bronchial anastomosis is a distinct site

Donor–recipient bronchial connection

Site exposed to local complications

Possible fungal involvement

Targeted anatomical assessment

Schematic clinical–anatomic reasoning; Not a published management protocol.

Slide 28 · Focal versus diffuse pulmonary infiltrates

Pattern

Textbook examples

Interpretive caution

Diffuse

CMV; P. jirovecii; drug reaction

Not specific for infection

Focal

Gram-negative bacteria; S. aureus; fungi

Not exclusive to infection

Either pattern

Malignancy listed in the differential

Correlate clinically

Slide 29 · Noninfectious infiltrates still matter

In immunocompromised hosts, drug reactions and malignant involvement can produce lung infiltrates.

In a lung allograft, rejection adds a critical noninfectious cause.

Radiology can identify an infiltrate without defining its pathogenesis.

Slide 30 · Mixed processes are possible

The parent section notes that more than one infectious agent can be present.

Infection and rejection also have overlapping clinical presentations.

Avoid interpreting a single clinical clue as proof of only one process.

Slide 31 · Acute rejection: Clinical syndrome

Acute rejection commonly causes fever, dyspnea, cough, and radiologic infiltrates.

The same findings can arise from pulmonary infection.

Transbronchial biopsy to help establish the diagnosis.

Slide 32 · Rejection begins with alloantigen recognition

Donor HLA differences

Recipient lymphocyte recognition

Alloreactive immune effectors

Inflammation and graft injury

Schematic of general transplant immunobiology applied to the lung.

Slide 33 · HLA disparity explains alloimmunity

Highly polymorphic HLA alleles differ between most donor–recipient pairs.

Recipient T cells can interpret donor alloantigens as foreign.

The alloreactive repertoire is large; Immunosuppression is required for graft survival.

Slide 34 · Direct alloantigen presentation

Donor antigen-presenting cell

Displays intact donor HLA

Recipient T-cell activation

Effector response

Source describes direct presentation as particularly important in acute CTL-mediated rejection.

Slide 35 · Indirect alloantigen presentation

Host antigen-presenting cell

Processes graft antigen

Presents antigen to host T cells

Alloimmune response

Source discusses a potentially greater role of this route in chronic rejection.

Slide 36 · Two T-cell effector arms

CD8+ T cells

Develop into cytotoxic T lymphocytes.

Can directly injure graft cells.

CD4+ T cells

Differentiate into cytokine-producing effectors.

Recruit and activate inflammatory responses.

Slide 37 · B cells and alloantibodies

B lymphocytes can recognize donor HLA and other polymorphic antigens.

T-cell help supports generation of anti-donor antibodies.

The general transplant-immunology section identifies both cellular and humoral rejection mechanisms.

Slide 38 · Immunosuppression targets alloimmune pathways

Drug class / agent

Textbook action

Pathologic rationale

Glucocorticoids

Reduce inflammation

Limit graft-damaging inflammation

Mycophenolate mofetil

Inhibits lymphocyte proliferation

Reduce effector expansion

Tacrolimus

Calcineurin inhibition

Reduce T-cell activation

Slide 39 · Acute rejection is not limited to early months

Lung acute rejection is most commonly seen weeks to months after transplantation.

It may present years after surgery, particularly if immunosuppression is reduced.

Time from transplantation therefore modifies—but does not eliminate—the diagnosis.

Slide 40 · Clinical overlap: Rejection versus infection

Finding

Acute rejection

Infection

Fever

May occur

May occur

Cough / dyspnea

May occur

May occur

Pulmonary infiltrates

May occur

May occur

Discriminating test in source

Transbronchial biopsy often used

Etiologic assessment needed

Slide 41 · Why biopsy becomes important

Fever + cough + infiltrates

Infection / rejection overlap

Obtain tissue when indicated

Assess graft inflammation

A teaching workflow based on source rationale; Local clinical protocols may differ.

Slide 42 · Acute rejection: Perivascular inflammation

Schematic inflammatory cuff

Mononuclear inflammatory cells aggregate around small blood vessels.

The inflammatory infiltrate is a principal acute rejection pattern.

Schematic — not a histologic micrograph.

Slide 43 · Acute rejection: Airway submucosal inflammation

Schematic inflammatory cuff

Inflammation can be located in the submucosa of small airways.

Perivascular and airway-centered patterns may coexist.

Schematic — not a histologic micrograph.

Slide 44 · Cell composition in acute rejection

Predominant

Lymphocytes

Plasma cells

Less numerous

Neutrophils

Eosinophils

Slide 45 · Morphology is a pattern, not a symptom label

Acute rejection is defined by tissue inflammatory patterns in a compatible setting.

A patient’s fever or infiltrate is not sufficient to infer perivascular lymphocytes.

Tissue findings should be interpreted with infection assessment and clinical context.

Slide 46 · What a transbronchial biopsy can demonstrate

Inflammatory cuffs around sampled small vessels.

Small-airway submucosal inflammatory infiltrates, if the airway is represented.

A limited sample must be interpreted with awareness of lesion distribution.

Slide 47 · Acute cellular airway inflammation and treatment

Acute cellular airway rejection as generally responsive to therapy.

Airway inflammation is considered a possible antecedent to later fibrotic obliteration.

Response in the acute phase contrasts with the poor reversibility of established obliteration.

Slide 48 · Chronic rejection: Progressive graft injury

Chronic rejection is a major long-term complication of lung transplantation.

It is associated with cough, dyspnea, and irreversible loss of lung function.

The most characteristic pathologic lesion is bronchiolitis obliterans.

Slide 49 · Long-term burden of chronic rejection

The Robbins text reports significant chronic rejection in at least half of patients at 3–5 years.

This is the textbook’s reported estimate, not a newly calculated contemporary registry rate.

Functional surveillance and recognition of progressive obstruction are therefore important.

Slide 50 · Bronchiolitis obliterans: Core lesion

The small-airway lumen is narrowed or completely occluded by fibrosis.

Active inflammation may be present or absent.

Fibrotic remodeling—not merely transient inflammation—explains persistent dysfunction.

Slide 51 · Normal airway to luminal obliteration

Patent lumen

Partially narrowed lumen

Fibrotic occlusion

Slide 52 · Why the fibrotic bronchiole obstructs airflow

Peribronchiolar / intraluminal fibrosis

Smaller conducting-airway caliber

Increased flow resistance

Persistent graft dysfunction

Physiologic interpretation of the Robbins morphologic description.

Slide 53 · Bronchiolitis obliterans is patchy

Variable airway narrowing across one conceptual sample

Affected bronchioles may be interspersed with relatively preserved airways.

A transbronchial sample may miss the diagnostic lesion.

Sampling schematic, not observed tissue or a sensitivity estimate.

Slide 54 · Consequences of longstanding chronic rejection

Small airways

Bronchiolitis obliterans.

Patchy fibrous luminal occlusion.

Broader architecture

Bronchiectasis may develop.

Pulmonary fibrosis may develop.

Slide 55 · Chronic rejection: Clinical–pathologic alignment

Clinical finding

Tissue correlate

Reasoning

Cough / dyspnea

Chronic airway and parenchymal damage

Reduced ventilatory function

Irreversible functional loss

Fibrotic small-airway occlusion

Fixed structural lesion

Biopsy may miss lesion

Patchy bronchiolitis obliterans

Sampling limitation

Slide 56 · Chronic fibrosis is difficult to reverse

Established bronchiolitis obliterans cannot be reversed.

Progression may sometimes be slowed or halted for a period.

This underlines the distinction between controlling inflammation and removing a mature fibrotic lesion.

Slide 57 · Acute and chronic rejection: Pathology

Feature

Acute rejection

Chronic rejection

Dominant change

Cellular inflammatory infiltrates

Fibrotic narrowing of bronchioles

Typical location

Perivascular / airway submucosa

Small-airway lumen

Clinical trajectory

May improve with therapy

Often irreversible dysfunction

Sampling issue

Biopsy aids diagnosis

Patchy lesion may be missed

Slide 58 · Infection and rejection: Integrated interpretation

Infection

Opportunistic and conventional pathogens.

Temporal patterns vary with prophylaxis.

Anastomotic involvement possible with fungi.

Rejection

Immune recognition of donor alloantigens.

Acute: Inflammatory infiltrates.

Chronic: Bronchiolar fibrosis.

Slide 59 · What the calendar can—and cannot—tell you

Early weeks

Bacterial infection

Weeks–months

Acute rejection

Months 3–12

Many infectious events

Years

Chronic rejection; Late acute rejection

All periods overlap. The calendar narrows the differential; It never establishes a diagnosis.

Slide 60 · EBV-associated B-cell lymphoma

EBV-associated B-cell lymphoma is an infrequent complication described after lung transplantation.

It most often arises within the transplanted lung.

A mass or infiltrate in an immunosuppressed recipient cannot automatically be labeled infection or rejection.

Slide 61 · Survival data require source context

An overall median lung-transplant survival of six years.

The excerpt also associates better outcomes with younger recipients and bilateral transplantation.

This textbook figure is not a separately verified current survival estimate and should be interpreted accordingly.

Slide 62 · Case 1: Infiltrates two weeks after transplantation

A recipient develops fever, cough, and a new pulmonary infiltrate two weeks after surgery.

Question: Which infectious category has the strongest timing association?

Expected reasoning: Bacterial infection predominates in the earliest weeks, but rejection remains possible.

Slide 63 · Case 2: Dyspnea four months after transplantation

Four months after transplantation, a patient develops fever, dyspnea, and radiologic infiltrates.

Question: Why is symptom-based discrimination unsafe?

Expected reasoning: Acute rejection and infection overlap; Biopsy can be diagnostically important.

Slide 64 · Case 3: Progressive decline several years later

A recipient has progressive cough, breathlessness, and sustained worsening of pulmonary function years later.

Question: Which structural lesion is most characteristic of chronic rejection?

Expected reasoning: Patchy bronchiolitis obliterans with fibrous small-airway occlusion.

Slide 65 · Diagnostic synthesis: Link syndrome to tissue

Allograft dysfunction

Timing + symptoms + imaging

Infection assessment + biopsy context

Inflammation or fibrotic airway lesion

An educational synthesis, not a comprehensive contemporary clinical diagnostic algorithm.

Slide 66 · Five distinctions to retain

The transplant indications include end-stage COPD, IPF, CF, and idiopathic/familial PAH.

Bilateral chronic infection requires replacing both lungs.

Early bacterial infection, opportunistic infection, and rejection overlap in time.

Acute rejection is inflammatory; Chronic rejection is characteristically fibrotic.

Bronchiolitis obliterans is patchy, often difficult to sample, and irreversible once established.

Slide 67 · References and scope

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. 2026. Chapter 15: The Lung; “Lung Transplantation,” pp. 650–651.

Robbins, Cotran & Kumar. Chapter 15: “Pneumonia in the Immunocompromised Host,” p. 650.

Robbins, Cotran & Kumar. Chapter 6: “Rejection of Tissue Transplants,” pp. 208–211.

Anatomical and mechanistic schematics in this lecture are original editable teaching diagrams, not clinical specimens.