PAX 5 Immunohistochemistry Test Lahore at Lahore PCR Lab

PAX 5 Immunohistochemistry at Lahore PCR Lab

PAX 5 Immunohistochemistry at Lahore PCR Lab is a highly specialized diagnostic pathology service designed to evaluate the expression of the Paired Box 5 (PAX-5) protein in tissue specimens. PAX-5, also known as B-cell lineage-specific activator protein (BSAP), is a critical transcription factor encoded by the PAX5 gene located on chromosome 9p13. This protein plays an indispensable role in early B-cell development, commitment, and differentiation. In the realm of clinical pathology, immunohistochemistry (IHC) utilizing the PAX-5 antibody serves as an invaluable diagnostic tool, particularly in hematopathology, for identifying cells of B-cell lineage and diagnosing various lymphoid malignancies. At Lahore PCR Lab in Lahore, Pakistan, this advanced diagnostic technique is performed with extreme precision to assist oncologists, hematologists, and general physicians in establishing accurate diagnoses for complex hematological disorders.

The primary clinical value of PAX 5 Immunohistochemistry at Lahore PCR Lab lies in its exceptional lineage specificity. During normal hematopoiesis, PAX-5 expression is initiated at the pro-B cell stage, maintained throughout all subsequent stages of B-cell maturation, and ultimately downregulated or completely lost during terminal differentiation into plasma cells. Consequently, PAX-5 is expressed in normal pre-B cells, mature B-cells, and the vast majority of B-cell neoplasms, while remaining absent in T-cells, myeloid cells, histiocytes, and plasma cells. This specific expression profile makes PAX-5 one of the most reliable and sensitive markers for B-cell lineage determination, especially when evaluating poorly differentiated or lineage-ambiguous tumors. By utilizing state-of-the-art IHC staining platforms and high-affinity monoclonal antibodies, the pathology team at Lahore PCR Lab can confidently localize the PAX-5 protein within the nuclei of target cells, providing clear, reproducible, and clinically actionable results.

Understanding the anatomical and pathological context of PAX-5 expression is vital for interpreting biopsy results. The test is typically performed on formalin-fixed, paraffin-embedded (FFPE) tissue sections obtained from lymph nodes, bone marrow biopsies, spleen, tonsils, or extra-nodal masses suspected of harboring lymphoma or leukemia. The diagnostic utility of PAX-5 extends beyond simple lineage identification; it is highly useful in distinguishing classical Hodgkin lymphoma (where Reed-Sternberg cells typically show weak, variable nuclear staining) from nodular lymphocyte-predominant Hodgkin lymphoma (where LP cells exhibit strong, diffuse nuclear staining). Furthermore, PAX-5 is a key marker in the diagnostic panel for B-cell acute lymphoblastic leukemia (B-ALL), diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, mantle cell lymphoma, and marginal zone lymphoma. By choosing Lahore PCR Lab, patients and clinicians in Lahore benefit from a rigorous diagnostic process that adheres to international laboratory standards, ensuring that every histopathological evaluation is both accurate and timely.

Clinical Procedure: What to Expect

Patient Preparation

Because PAX 5 Immunohistochemistry at Lahore PCR Lab is a laboratory test performed on tissue specimens rather than directly on the patient, preparation depends entirely on whether the patient is undergoing an active biopsy procedure or simply submitting an existing tissue block for a second opinion.

• Existing Tissue Blocks (FFPE): If you are submitting a previously collected formalin-fixed, paraffin-embedded tissue block or unstained slides for PAX-5 IHC testing, no physical preparation is required. You must ensure that you bring the original histopathology report, clinical referral slip, and all relevant medical records to Lahore PCR Lab.
• Active Biopsy Procedures: If the tissue sample is to be collected via an active biopsy (such as a core needle biopsy, excisional lymph node biopsy, or bone marrow aspiration and trephine biopsy), you must follow the specific preparation guidelines provided by your performing physician or radiologist.
• Medication Review: Inform your clinical team of all medications you are currently taking, especially blood thinners, anticoagulants, or antiplatelet agents, as these may need to be temporarily discontinued prior to an invasive biopsy procedure.
• Fasting Requirements: Fasting is generally not required for local anesthetic biopsies, but may be necessary if the biopsy is scheduled under general anesthesia or deep conscious sedation.
• Post-Biopsy Care: Ensure you arrange for a family member or friend to accompany you home after an invasive biopsy procedure, particularly if sedative medications are administered.

During the Procedure

The laboratory phase of PAX 5 Immunohistochemistry at Lahore PCR Lab involves a series of highly controlled, automated, and manual steps executed by skilled histotechnologists and evaluated by consultant pathologists.

• Specimen Reception and Accessioning: The tissue specimen, once received at Lahore PCR Lab, is assigned a unique laboratory identification number to ensure absolute traceability throughout the diagnostic workflow.
• Tissue Sectioning: The formalin-fixed, paraffin-embedded (FFPE) tissue block is mounted on a microtome, and ultra-thin sections (typically 3 to 5 microns in thickness) are cut and transferred onto specialized, positively charged glass slides.
• Deparaffinization and Rehydration: The tissue slides are heated and treated with clearing agents (such as xylene) and graded alcohols to remove the paraffin wax and rehydrate the tissue, preparing it for aqueous antibody reactions.
• Antigen Retrieval: To expose the PAX-5 epitopes that may have been masked during formalin fixation, the slides undergo Heat-Induced Epitope Retrieval (HIER) using specialized buffer solutions under controlled temperature and pressure conditions.
• Primary Antibody Incubation: The tissue sections are incubated with a highly specific monoclonal antibody directed against the human PAX-5 protein. The antibody binds specifically to the PAX-5 transcription factor located within the cell nuclei.
• Detection System and Chromogen Visualization: A secondary detection system, typically utilizing a horseradish peroxidase (HRP) polymer, is applied, followed by the addition of a chromogen substrate such as diaminobenzidine (DAB). This reaction produces a highly visible, insoluble brown precipitate precisely at the site of PAX-5 localization within the nucleus.
• Counterstaining and Coverslipping: The slides are counterstained with hematoxylin to stain non-reactive nuclei blue, providing anatomical contrast. The slides are then dehydrated, cleared, and coverslipped for permanent preservation.
• Microscopic Evaluation: A consultant pathologist examines the stained slides under a high-resolution light microscope to assess the intensity, pattern, and distribution of nuclear PAX-5 staining within the tissue architecture.

When is a PAX 5 Immunohistochemistry Performed?

B-Cell Acute Lymphoblastic Leukemia Diagnosis

Physicians frequently request PAX 5 Immunohistochemistry at Lahore PCR Lab when evaluating bone marrow or peripheral blood involvement in suspected cases of acute leukemia. PAX-5 is highly expressed in B-cell acute lymphoblastic leukemia (B-ALL) and is exceptionally useful in distinguishing B-ALL from T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Because PAX-5 expression is restricted to the B-cell lineage from the earliest stages, a positive nuclear signal confirms B-cell lineage commitment, helping oncologists select the correct chemotherapy protocol.

Distinguishing Hodgkin Lymphoma Subtypes

PAX-5 IHC is an essential component of the diagnostic panel used to differentiate classical Hodgkin lymphoma (CHL) from nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) and other large B-cell lymphomas. In classical Hodgkin lymphoma, the neoplastic Reed-Sternberg cells typically exhibit a characteristic weak, variable, or “dim” nuclear staining for PAX-5, whereas the surrounding normal B-lymphocytes show strong, intense staining. In contrast, the lymphocytic and histiocytic (LH) cells of NLPHL exhibit strong, diffuse nuclear PAX-5 expression, aiding in precise disease classification.

Lineage Determination of Undifferentiated Neoplasms

When a patient presents with a highly undifferentiated metastatic tumor or a mediastinal mass of unknown origin, identifying the primary cell lineage is critical for treatment planning. Pathologists at Lahore PCR Lab utilize PAX-5 IHC as part of a comprehensive antibody panel to determine if the undifferentiated neoplasm has a B-cell lymphoid origin. A positive nuclear PAX-5 result effectively rules out epithelial, mesenchymal, melanocytic, and T-cell malignancies, steering the clinical team toward appropriate lymphoma-directed therapies.

Evaluation of Lymphadenopathy and Splenomegaly

Persistent, unexplained lymphadenopathy (swollen lymph nodes) or splenomegaly (enlarged spleen) often warrants a tissue biopsy to rule out lymphoproliferative disorders. PAX-5 Immunohistochemistry is performed on these biopsy specimens to map the distribution of B-cells within the lymphoid tissue. It helps identify abnormal follicular patterns, diffuse sheets of B-cells characteristic of diffuse large B-cell lymphoma (DLBCL), or atypical lymphoid infiltrates in the splenic red and white pulp, providing critical diagnostic clarity.

Assessment of Minimal Residual Disease and Therapy Monitoring

Following chemotherapy, immunotherapy, or bone marrow transplantation for B-cell malignancies, clinicians must assess the patient for minimal residual disease (MRD) or disease recurrence. PAX-5 IHC is highly sensitive in detecting sparse, residual neoplastic B-cells within follow-up bone marrow trephine biopsies or tissue samples. Its distinct nuclear localization allows pathologists to easily identify individual positive cells even amidst a background of regenerating hematopoietic elements or inflammatory cells.

What Does a PAX 5 Immunohistochemistry Detect?

PAX 5 Immunohistochemistry at Lahore PCR Lab is designed to detect, localize, and quantify the expression of the PAX-5 transcription factor. The diagnostic findings obtained from this test are highly specific and provide critical insights into the cellular composition of the tissue specimen. Specifically, this test detects:

• Nuclear Localization: The precise presence of PAX-5 within the nuclei of target cells, visualized as a distinct brown staining under light microscopy.
• Normal B-Lymphocytes: Strong, uniform nuclear staining in normal B-cells located within the lymphoid follicles, mantle zones, and marginal zones of healthy lymphoid tissue.
• B-Cell Acute Lymphoblastic Leukemia (B-ALL): Diffuse, strong nuclear expression in lymphoblasts, confirming B-cell lineage in acute leukemia cases.
• Diffuse Large B-Cell Lymphoma (DLBCL): Intense nuclear PAX-5 staining in large, atypical lymphoid cells, confirming a B-cell origin for this aggressive lymphoma.
• Follicular Lymphoma: Strong nuclear positivity in neoplastic germinal center B-cells (centrocytes and centroblasts) forming abnormal follicular structures.
• Mantle Cell Lymphoma: Positive nuclear staining in small-to-medium-sized atypical lymphocytes expressing cyclin D1 and CD5, confirming B-cell lineage.
• Marginal Zone Lymphoma: Nuclear PAX-5 expression in monocytoid B-cells, marginal zone cells, and small lymphocytes.
• Burkitt Lymphoma: Uniform, highly intense nuclear staining in medium-sized, highly proliferative neoplastic B-cells.
• Classical Hodgkin Lymphoma (CHL): Characteristically weak, variable, or “dim” nuclear staining in diagnostic Reed-Sternberg cells and their variants.
• Nodular Lymphocyte-Predominant Hodgkin Lymphoma (NLPHL): Strong, diffuse nuclear staining in LP (popcorn) cells, distinguishing it from CHL.
• Small Lymphocytic Lymphoma (SLL) / Chronic Lymphocytic Leukemia (CLL): Strong, diffuse nuclear staining in small, mature-appearing neoplastic B-lymphocytes.
• Lymphoplasmacytic Lymphoma: Positive nuclear staining in the B-cell component, with variable or absent staining in the plasmacytoid/plasma cell component.
• Absence of Expression in T-Cells: Complete lack of staining in normal and neoplastic T-lymphocytes, confirming the marker’s specificity.
• Absence of Expression in Myeloid Cells: Negative staining in granulocytic, erythroid, and megakaryocytic lineages in bone marrow specimens.
• Absence of Expression in Plasma Cells: Downregulation of PAX-5 in mature plasma cells and multiple myeloma, aiding in the differentiation of plasmablastic lymphoma from myeloma.
• Absence of Expression in Epithelial Tumors: Negative staining in carcinomas, helping rule out epithelial malignancies in poorly differentiated tumors.
• Absence of Expression in Melanomas: Negative staining in metastatic melanomas, preventing diagnostic confusion.
• Absence of Expression in Sarcomas: Negative staining in mesenchymal tumors, confirming lymphoid vs. non-lymphoid origin.
• Co-expression Patterns: Pathologists evaluate PAX-5 alongside other markers (like CD19, CD20, CD3, CD79a, and TdT) to construct a complete immunophenotypic profile.
• Tissue Architecture Preservation: The preservation of normal lymphoid architecture or its destruction by PAX-5 positive neoplastic infiltrates.
• Infiltration Density: The percentage and spatial distribution of PAX-5 positive cells within the biopsy specimen.
• Atypical Localization: The presence of PAX-5 positive cells in non-lymphoid organs, indicating metastatic or extranodal lymphoma involvement.

Turnaround Time and Report Access at Lahore PCR Lab

At Lahore PCR Lab, we understand that a rapid and highly accurate diagnosis is critical for patients facing potential hematological malignancies. The turnaround time for PAX 5 Immunohistochemistry at Lahore PCR Lab typically ranges from 3 to 5 working days. This timeframe is necessary to ensure meticulous tissue processing, optimal antigen retrieval, precise staining protocols, and comprehensive microscopic evaluation by our consultant pathologists. In complex cases requiring additional antibody panels or consensus consultations, the reporting time may be extended to ensure the highest level of diagnostic accuracy.

Patients and referring physicians can easily access diagnostic reports online through the official Lahore PCR Lab web portal. Once the report is finalized and signed off by the consultant pathologist, an automated SMS notification is sent to the patient’s registered mobile number with a direct link to download the secure PDF report. Physical copies of the report can also be collected directly from our main diagnostic center in Lahore or any of our designated collection points. Our digital reporting system ensures that critical diagnostic information is delivered promptly to your clinical team, facilitating the immediate initiation of appropriate treatment strategies.

PAX 5 Immunohistochemistry Findings Overview

Structure / Parameter Evaluated	Normal Findings	Possible Abnormal Findings
Cortical Lymphoid Follicles	Strong nuclear PAX-5 staining restricted to follicular B-lymphocytes (germinal centers and mantle zones).	Disrupted follicular architecture with diffuse sheets of PAX-5 positive cells (indicative of lymphoma).
Paracortical (T-cell) Zones	Negative PAX-5 staining; normal resident T-lymphocytes do not express PAX-5.	Infiltration of PAX-5 positive neoplastic B-cells into paracortical regions, or complete effacement by PAX-5 negative T-cell lymphoma.
Bone Marrow Core Biopsy	Sparse, scattered PAX-5 positive mature B-cells (typically <5% of total cellularity).	Hypercellular marrow with dense aggregates or diffuse sheets of PAX-5 positive lymphoblasts (B-ALL) or lymphoma cells.
Reed-Sternberg Cells (Hodgkin)	Not present in normal lymphoid tissues.	Weak, variable, or “dim” nuclear PAX-5 staining in large, multinucleated Reed-Sternberg cells (Classical Hodgkin Lymphoma).
Lymphocytic & Histiocytic (LP) Cells	Not present in normal lymphoid tissues.	Strong, intense nuclear PAX-5 staining in LP (“popcorn”) cells (Nodular Lymphocyte-Predominant Hodgkin Lymphoma).
Plasma Cells / Plasmacytoid Cells	Negative PAX-5 staining; mature plasma cells downregulate PAX-5 expression.	Variable or weak expression in plasmablastic lymphoma; generally negative in multiple myeloma.
Undifferentiated Epithelial/Mesenchymal Cells	Negative PAX-5 staining; epithelial and mesenchymal tissues do not express PAX-5.	Negative staining confirms non-B-cell origin; positive staining in a poorly differentiated tumor strongly suggests B-cell lineage.

Note: Diagnostic findings should always be interpreted by a qualified healthcare professional together with the patient’s symptoms, medical history, physical examination, laboratory investigations, previous imaging studies, and other relevant clinical information. Additional investigations or specialist consultation may be recommended depending on the findings.

Why Choose Lahore PCR Lab for PAX 5 Immunohistochemistry?

• Experienced Healthcare Professionals: Our pathology department is led by highly qualified consultant histopathologists with extensive experience in hematopathology and advanced immunohistochemical diagnostics.
• Patient-Focused Care: We prioritize patient comfort, clear communication, and compassionate support throughout the diagnostic journey, ensuring a seamless experience from sample submission to report delivery.
• Quality Diagnostic Services: Lahore PCR Lab adheres to strict internal and external quality control protocols, ensuring that every immunohistochemical stain is highly reproducible and clinically accurate.
• Professional Reporting: Our diagnostic reports are comprehensive, detailed, and structured according to international pathological guidelines, providing clear diagnostic conclusions for clinical decision-making.
• Modern Diagnostic Approach: We utilize advanced automated staining platforms and high-affinity monoclonal antibodies to minimize manual errors and deliver superior staining quality.
• Comfortable Environment: Our main facility in Lahore offers a clean, modern, and comfortable environment for patients visiting for sample submission or consultation.
• Convenient Location: Strategically located in Lahore, Pakistan, our diagnostic center and collection points are easily accessible to patients from all parts of the city and surrounding regions.
• Commitment to Accurate Diagnosis: We are dedicated to providing precise diagnostic answers for complex oncological and hematological cases, supporting clinicians in delivering targeted patient care.