The ontogeny of the gut-associated lymphoid tissue in short bowel syndrome

Abstract

Newborns suffering from short bowel syndrome (SBS) after massive intestinal resection have numerous infectious complications, which may be due to immunoincompetence from the loss of gut-associated lymphoid tissue (GALT). This study examines the ontogeny of GALT in the rat with SBS. A total of 36 3-week-old rats were divided into two groups: I, sham operated (C, n = 16); and II (SBS, n = 20), with a 50% resection of small intestine with jejunoileostomy. At 4, 5, 6, and 10 weeks of age the animals were sacrificed and the GALT was assessed by video analysis and immunoperoxidase monoclonal antibodies, OX8 (CD8), W-3/25 (CD4), and MARA-2 (IgA). The data were expressed as positive staining lymphocytes per 10 4 μm 2 (mean ± SD). ∗ OX8 W-3/25 MARA-2 Results: C(4) SBS(5) C(4) SBS(5) C(4) SBS(5) Week 4 33±7 43±14 20±6 31±10 7±4 10±2 Week 5 43±14 46±19 26±3 27±7 11±7 6±2 Week 6 36±11 44±12 25±9 7±9 ∗∗ 10±1 4±4 ∗ Week 10 39±9 11±3 ∗ 28±10 5±10 ∗ 15±3 6±2 ∗ ∗ P < 0.01 ∗∗ P < 0.05 vs control (C). In the sham group there was an increase in all lymphocyte subsets over time. In the SBS group there was a rapid fall in OX8 and W-3/25 T-lymphocytes by 10 weeks, with no increase in IgA plasma cells at 6 and 10 weeks. This study demonstrates that in the massive bowel resection in the suckling rat decreases the T- and B-lymphocyte populations in the GALT. This lack of development may underlie the associated infectious complications and malabsorption in SBS.