Humoral Immunity in Libyan Patients with Ulcerative Colitis

The aetiology of ulcerative colitis remains uncertain. Most of the clinical manifestations are related to inflammation. Also, the most frequently used drugs in the treatment of ulcerative colitis, sulphasalazine and corticosteroids, have expressed anti-inflammatory properties. In our present study we have investigated serum levels of complements (C3, C4) and immunoglobulins (IgG, IgA, IgM, IgD, IgE) in 29 Libyan patients with ulcerative colitis (age: 1757 years; sex: 17 males, 12 females) and 29 healthy Libyans (age: 1859 years; sex: 16 males, 13 females) as controls. It was observed that at active stage of the disease (pretreatment) serum levels of C4, IgA and IgE were significantly elevated, whereas C3 levels were significantly lowered compared to control subjects (p<0.00001). Follow-up studies showed that C3 and C4 levels were brought to normal levels at remission after 2 months of therapy with different drug regimens and at 1 year of maintenance therapy. But serum IgA and IgE levels remained significantly elevated (p<0.00001) even at remission after treatments with different drug regimens, although they were lowered to some extent, but not significantly. The clinical evaluations at 2 months of treatment and at 1 year of maintenance therapy fulfilled the criteria for remission of the disease activity. Our results were therefore taken as indications that alternative pathway activation of the complement system was present which may be responsible for the aggravated inflammation present in ulcerative colitis. It has been proposed that complement activation in our patients may be mediated through IgA and/or IgE-containing immune complexes formed secondary to immune response against initial, but unknown, assaulting agent.