TYPES OF WHITE BLOOD CELLS (WBCS)

TYPES OF WHITE BLOOD CELLS (WBCS) – KRIYASHAREERA AND MODERN PHYSIOLOGY PERSPECTIVE

• White blood cells (WBCs) or Leukocytes are an important component of rakta dhatu involved in vyadhi pratibandhakatva (immunity).

• They play a key role in body defense mechanisms through phagocytosis, antibody production, and cell-mediated immunity.

• In modern physiology, leukocytes are classified based on presence or absence of granules in cytoplasm and nucleus morphology.

SANSKRIT REFERENCE

रुधिरं स्थिरतां यान्ति येन रोगा न जायते।
स एव बलवान् नित्यं जीवत्यायुष्यमायुषा॥
– चरकसंहिता सूत्रस्थानम् २८/७

रुधिरं बलवर्णायुःसुखं जीवितमेव च।
तस्मात्तदात्ययेनाशु यत्नेन प्रतिपादयेत्॥
– अष्टाङ्गहृदयम् सूत्रस्थानम् ११/४

CLASSIFICATION OF WBCS (MODERN VIEW)

White blood cells are broadly classified into:

• Granulocytes – Contain granules in cytoplasm.

• Agranulocytes – Lack granules in cytoplasm.

GRANULOCYTES

NEUTROPHILS

• Percentage: 60–70% of total WBCs.

• Nucleus: Multilobed (polymorphonuclear).

• Cytoplasm: Fine granules.

• Function:

  • First line defense.

  • Phagocytosis of bacteria and dead cells.

  • Release enzymes like lysozymes, defensins, and oxidants.

• Increase in bacterial infection (neutrophilia).

• Life span: 6–8 hours in circulation, 1–2 days in tissues.

EOSINOPHILS

• Percentage: 1–4%.

• Nucleus: Bilobed.

• Cytoplasm: Large granules staining with eosin.

• Function:

  • Combat parasitic infections.

  • Modulate allergic responses.

  • Release histaminase, arylsulfatase.

• Eosinophilia seen in asthma, parasitic infections.

BASOPHILS

• Percentage: 0.5–1%.

• Nucleus: S-shaped.

• Cytoplasm: Large basophilic granules.

• Function:

  • Involved in hypersensitivity reactions.

  • Granules contain histamine, serotonin, and heparin.

  • Cause vasodilation and bronchoconstriction in allergies.

AGRANULOCYTES

LYMPHOCYTES

• Percentage: 20–25%.

• Types:

  • B-lymphocytes: Produce antibodies (humoral immunity).

  • T-lymphocytes: Cell-mediated immunity.

    • Helper T cells (CD4), Cytotoxic T cells (CD8), Regulatory T cells.

  • Natural Killer Cells (NK): Destroy infected or tumor cells.

• Nucleus: Large and round, scanty cytoplasm.

• Increased in viral infections.

MONOCYTES

• Percentage: 3–8%.

• Nucleus: Kidney or horseshoe-shaped.

• Cytoplasm: Abundant and agranular.

• Function:

  • Transform into macrophages in tissues.

  • Phagocytose dead cells, microbes.

  • Secrete cytokines like interleukin-1, TNF-α.

LIFE SPAN AND FORMATION

• Leukopoiesis: Formation of WBCs from pluripotent hematopoietic stem cells in bone marrow.

• Stimulated by CSFs (Colony Stimulating Factors) and interleukins.

• Lifespan varies:

  • Neutrophils: Few hours to 1–2 days.

  • Lymphocytes: Weeks to years.

  • Monocytes: 1–3 days in blood, months as macrophages.

AYURVEDIC CORRELATION

• WBCs can be correlated with rakta dhatu upadhatu and ojas.

• Vyadhikshamatva (immunity) in Ayurveda includes both sharirika and manasika components supported by dhatusara, bala, ojas, and agni.

• Pitta dosha (specifically ranjaka pitta) is linked to functions of rakta dhatu, possibly corresponding to defense mechanisms.

ओजो नाम्ना परं तेजः सर्वभूतानामुच्यते।
तद्बलं धारणं शक्तिः स्थितिस्तुष्टिर्यथोचितम्॥
– अष्टाङ्गहृदयम् सूत्रस्थानम् ११/४०

DIFFERENTIAL LEUCOCYTE COUNT (DLC)

PHYSIOLOGICAL VARIATIONS IN WBC COUNT

• Leukocytosis: Increase in WBC count seen in infections, inflammation.

• Leukopenia: Decrease in WBCs due to bone marrow suppression, radiation.

• Physiological increase: Seen in pregnancy, exercise, stress.

RELEVANT TOPICS FROM SEMBULINGAM HUMAN PHYSIOLOGY TEXTBOOK

• Chapter: Blood and Body Fluids

  • WBC types and morphology.

  • Functions of each leukocyte.

  • Leukopoiesis process.

  • Immune responses involving lymphocytes.

  • Role of cytokines and interleukins.

  • Clinical conditions like leukemia, leukopenia, and neutropenia.