Immunohistochemical Studies on the Development of Human Foetal Spleen

Background: Spleen is one of the organs of interest for researchers since a long time. Though, detailed morphometric of spleen is there in the literature but immunohistochemical studies on spleen at different stages in the foetal period is less available. Hence, the present study aims to find out the immunohistochemical development of human spleen in different gestational weeks. Materials and Methods: The study was carried out on 40 human foetuses of known gestational age in the Department of Anatomy, MGM Medical College. After dissection the spleens were removed and fixed in 10 % buffered formalin solution for 10 days. Tissue blocks were cut and then embedded in paraffin after dehydration in a graded ethanol series. Serial sections were prepared for haematoxylin and eosin for histology and immunohistochemical examination. Results: In the spleen of the 16th gestational week, T and B lymphocytes were scattered in the splenic parenchyma. At 22nd gestational week, T and B lymphocytes became denser. After 24th gestational week white pulp was specialized into T-cell and B-cell region. CD3 positive T-lymphocytes around the arteriole formed periarteriolar lymphatic sheath. CD20 positive B-lymphocytes around the arteriole to form lymphoid follicle. At later stages immunoreactive CD3 positive cells were reduced as compared to the CD20 lymphocytes in the spleen. Conclusion: The study concludes that the density of immunoreactive CD3 T-lymphocytes was less as compared to the CD20 B-lymphocytes in the spleen throughout the gestation. The T and B lymphocytes increased in the later gestational stages.