 We assume that B cells involved in a chronic disease state undergo Ig gene diversification for much longer times than B cells in normal short-term immune responses, and hence Ig gene sequences from IBD-related B cells will exhibit a high degree of clonality. There may also be biases in specific Ig variable region V gene segment usage, as has been observed in other chronic diseases. Hence, the sequences obtained under aim 1 will be aligned with human germline V segment sequences, in order to identify any possible biases in V segment usage, and to identify clonal relationships between sets of sequences from the same patient. Since even gut samples from healthy humans contain many clonally related Ig gene sequences see below, we expect to find many such clonal sequences in most samples. 