Microscopic colitis is characterized by an increase in inflammatory cells , particularly lymphocytes , in colonic biopsies with an otherwise normal appearance and architecture of the colon.  Inflammatory cells are increased both in the surface epithelium ("intraepithelial lymphocytes") and in the lamina propria . The key feature is more than 20 intra-epithelial lymphocytes per 100 epithelial cells.  These are the principal features of lymphocytic colitis. An additional distinguishing feature of collagenous colitis is a thickened subepithelial collagen layer, which may be up to 30 micrometres thick, that occurs in addition to the features found in lymphocytic colitis.  The fact that the two types of microscopic colitis share many features including epidemiology, risk factors and, response to therapy has led to the suggestion that they are actually subtypes of the same disease. 
SIMPONI ® (golimumab) is a prescription medicine. SIMPONI ® can lower your ability to fight infections. There are reports of serious infections caused by bacteria, fungi, or viruses that have spread throughout the body, including tuberculosis (TB) and histoplasmosis. Some of these infections have been fatal. Your doctor will test you for TB before starting SIMPONI ® and will monitor you for signs of TB during treatment. Tell your doctor if you have been in close contact with people with TB. Tell your doctor if you have been in a region (such as the Ohio and Mississippi River Valleys and the Southwest) where certain fungal infections like histoplasmosis or coccidioidomycosis are common.