The document outlines lymphopoiesis, detailing the development of lymphoid stem cells into B and T lymphocytes, with specific sites of development such as the bone marrow and thymus. It describes the regulatory role of interleukins in the maturation process and provides characteristics of various cell types including lymphocytoblasts, prolymphocytes, and plasma cells. Additionally, it highlights changes in cell morphology during maturation and the origin of different cell types.

1. LYMPHOPOIESIS
Developed by Dr.
Abdulrazzak Othman Alagbare- Clinical Pathologist -Hematology Lecturer _
MD-CMP

2. NON-GRANULAR CELLS (LYMPHOID
GROUP)
Lymphoid stem cells:
 These divide to form lymphoid progenitor
cells which differentiate into B & T
lymphocytes.
 Early development of B lymphocytes takes
place in the bone marrow and lymphoid
tissues,
 and development of T lymphocytes in the

3. LYMPHOID GROUP
Origin:
1-bone marrow and thymus
2-lymphoid tissue (spleen, lymphnodes,)
Lymphoid group regulation
 Regulated by: Inter-Leukines (IL 1 up to 21).

4. DEVELOPMENT STEPS
• Development steps are the following
• Lymphocytoblast  Prolymphocyte 
Lymphocytes (T and B lymphocytes)
• Regulation: by interleukin (IL)-1 and IL-6

5. Prolymphocyte
Size: 9 to 18 μm
N:C: 3:1
Chromatin: Nucleoli
present, slightly
coarsened chromatin
Cytoplasm: Gray-
blue, mostly blue at
edges
Small Lymphocyte
Size: 7 to 18 μm
N:C: 4:1
Chromatin: Oval nucleus
with coarse lumpy
chromatin
Cytoplasm: Usually just a
thin border, (rim of
cytoplasm)
Large Lymphocyte
Size: 9 to 12 μm
N:C: 3:1
Chromatin: Looser chromatin
pattern, more transparent
Cytoplasm: Larger amount of
cytoplasm, lighter in color

6. PLASMA CELLS
 They are type of B lymphocyte
 Their function to produce antibodies after B cells
stimulation with antigen
 Origin: Bone marrow not found in the peripheral blood
1- Plasma blast:- 2- Proplasma cells: 3- Plasma
cells
-This appearance is not found
in peripheral blood or bone
marrow

7. Plyripotent
Stem cell
Myeloid
stem cell
Granulocytic
cells
Neutr-
Eosin-
Basophil
Erythrocytes
Monocytic
Thrombocyte
Lymphoid
stem cell
B cells
Plasma
cells
T cells

9. Changes
during cells
maturation

10. may be
disappear (RBC)
may be lobulated
(Granualar cells)
may be fragillated
(Platelets)
May be remain
rounded (Lymphocytes
may be become
unshaped
(Monocyte)
Remain rounded
eccentric one, two or
three nucleus (plasma
cells)

11. CHANGES OF THE PLASMA
1-may be
contain visible
granules
(Granular cells)
2-may be
contain no
visible
granules
(monocyte)
3-may be non
contain granules
(RBC)
4-decrease in
volume (lymphocyte

12. END OF THE LESSON
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