Colitis Severity Score for Innate Immune-Mediated Mouse Models of Colitis

The Excel sheet to automatically generate total score from characteristics’ scores can be downloaded by clicking here

About the Score

The Boone-Mayer Colitis Severity Score uses a rigorously tested equation for scoring colitis severity in H&E slides of mouse models’ colons based on 4 standard characteristics of colitis: crypt hyperplasia, crypt density, abscess count, and immune cell infiltration.  The purpose of this equation is to standardize the way colitis severity is scored within the IBD research community as no standard equation has been decided upon.  This equation is modified from a heavily cited scoring methodology by Koelink et al. (linked on menu). More information on this equation can be found in the article linked on the sidebar menu. Additional information on how to score individual characteristics can be found in the section below.

How to Score Individual Characteristics of Colitis

When giving a score to each of the following characteristics, first ensure you are analyzing all tissue sections on the slide not just one portion of the slide.  Second, ensure you are scoring at 5x magnification for abcesses and 10x magnification for the remaining 3 characteristics.  Each of the following characteristics are scored on an integer scale of 0 (healthy) to 3 (severe colitis) except abcess number is any positive integer or 0. The descriptions of how to score individual characteristics are adapted from Koelink et al.’s original article by Katelyn Ruley-Haase and Toni Boger-May.

Photo credits to Koelink et al.

Crypt Hyperplasia (crypt elongation) is when the length of the crypts of the colon is increased from the standard crypt length of healthy colons.

0 – None

1 – Slight increase in crypt length

2 – 2 to 3-fold increase in crypt length

3 – >3-fold increase in crypt length

Photo credits to Koelink et al.

Crypt Density: Density will vary based on what portion of the colon you are scoring. Proximal and distal colons tend to have standard appearance of rectangular crypts. Cecums tend to have circular appearances as well. Therefore, look for the general overall collapse of structure when scoring cecums.

0 – Normal

1 – Decreased by <10%

2 – Decreased by 10-50%

3 – Decreased by >50%

Photo credit to Koelink et al.

Abcess Number: An abcess is a pocket of ~5+ dead cells (primarily neutrophils) surrounded by a cell wall.  This is the only characteristic that should be scored at 5x magnification.  If the abcess is not visible this zoomed-out, it does not count as an abcess. For this equation, abcesses only count in crypts not lumen or muscle layer. (In Koelink et al. scoring, they counted in both crypts and muscle layer.)

Photo credits to Koelink et al.

Inflammatory Infiltrate

0 – None

1 – Increased presence of inflammatory cells

2 – Infiltrates are also in submucosa

3 – Transmural (throughout the whole wall)