Classic Hodgkin lymphoma is a B-cell malignancy defined by rare Reed-Sternberg cells within an inflammatory background, requiring a targeted immunohistochemical panel of CD3, CD15, and CD30 to separate it from cellular mimics.
Pathologists Use Protein Markers to Identify Hodgkin Lymphoma
- Targeted Markers: Pathologists use specific proteins—CD3, CD15, and CD30—to accurately identify Hodgkin lymphoma and rule out similar-looking cancers.
- Overcoming Mimics: Morphology alone is insufficient because other lymphomas share visual traits with Hodgkin cells, making protein profiling essential for correct diagnoses.
- Therapeutic Value: Identifying CD30 expression directly determines a patient’s eligibility for targeted antibody-drug conjugate therapies like brentuximab vedotin.
The 1982 Discovery of CD30
CD30 was first identified in 1982 as the Ki-1 antigen using a monoclonal antibody raised against a Hodgkin lymphoma cell line. It was later cloned and classified as a member of the tumor necrosis factor receptor superfamily, designated as TNFRSF8.
Under normal physiological conditions, CD30 is expressed weakly and focally on a small subset of activated T and B lymphocytes. Conversely, it is strongly and uniformly overexpressed on Hodgkin and Reed-Sternberg cells and anaplastic large cell lymphoma cells, establishing it as the essential anchor marker of the diagnostic panel.
Conventional immunohistochemical protocols can occasionally under-detect low levels of CD30 expression. A 2024 study utilizing a staining protocol optimized for low-expression detection alongside an Allred-like scoring system demonstrated that 10 percent of classic Hodgkin lymphoma cases yielded low CD30 scores, while 3 percent tested entirely negative. Consequently, CD30 negativity does not completely exclude the diagnosis, pointing clinicians toward specialized protocols in ambiguous cases.
CD15 Supports Hodgkin Lymphoma Diagnoses via Specific Staining
CD15, a carbohydrate epitope also known as Lewis X or SSEA-1, has supported Hodgkin lymphoma diagnoses since the 1980s. Reed-Sternberg cells typically display a characteristic membranous and paranuclear staining pattern.
An early 1987 review encompassing 571 cases of Hodgkin disease and 386 cases of non-Hodgkin lymphoma determined an overall CD15 sensitivity of 80 percent, rising to 91 percent when lymphocyte-predominant cases were excluded. Specificity sat at approximately 81 percent, given that nearly one in five non-Hodgkin lymphomas also expressed CD15.
Recent comprehensive reviews confirm CD15 positivity in roughly 75 percent of classic Hodgkin lymphoma cases within a fraction of Reed-Sternberg cells. Its absence does not rule out the disease when CD30 and PAX5 findings support the diagnosis. Concurrently, CD3 acts as the primary T-cell lineage exclusion marker.
While HRS cells remain characteristically CD3-negative, background reactive T cells and peripheral T-cell lymphomas light up strongly. However, some anaplastic large cell lymphomas display a null phenotype, lacking T-cell markers entirely, which demonstrates why single markers cannot stand alone.
| Marker | Normal Distribution | Expression in cHL | Primary Diagnostic Role |
|---|---|---|---|
| CD30 | Rare activated T and B cells | Strong and uniform | Anchor marker for HRS cells and ALCL |
| CD15 | Granulocytes | Aberrant (approx. 75% of cases) | Supportive pattern confirmation |
| CD3 | Pan-T-cell antigen | Negative in HRS cells | Lineage exclusion and T-cell identification |
Classification Frameworks and Diagnostic Algorithms
This modern diagnostic work-up operates within two primary classification systems published in 2022: the fifth edition of the World Health Organization Classification of Haematolymphoid Tumours and the International Consensus Classification.
Both frameworks retain classic Hodgkin lymphoma as a distinct entity defined by its Reed-Sternberg immunophenotype. They diverge primarily in the nomenclature of nodular lymphocyte-predominant Hodgkin lymphoma, which the International Consensus Classification renamed nodular lymphocyte-predominant B-cell lymphoma to show its distinct B-cell biology.
Because individual markers carry distinct limitations—such as CD15 negativity in a substantial minority of cases and CD30 expression shared across other lymphomas—expert consensus recommends a core panel combining CD3, CD20, CD15, CD30, and PAX5. This combined pattern-based approach separates classic Hodgkin lymphoma from peripheral T-cell lymphomas and large B-cell lymphoma mimics. Accurate differentiation remains paramount because these malignancies require entirely different treatment regimens and carry distinct clinical outcomes.
Comprehensive Panel Analysis Prevents Misdiagnosis
Pathological evaluation must never rely on single-marker testing, as overlapping antigen profiles require comprehensive panel analysis to avoid misdiagnosis and inappropriate therapeutic selection.
References
- World Health Organization Classification of Haematolymphoid Tumours (WHO-HAEM5), 2022.
- International Consensus Classification, published in 2022.
- Cureus Narrative Review: CD3, CD15, and CD30: An Integrated Immunohistochemical Panel for the Diagnosis of Hodgkin Lymphoma and Its Mimics, August 2026.
