“…All of these observations suggest that an infectious agent, or antigens from it, in the joint, combined with host immune processes, are critical in the genesis of RS. While there have been reports of successful chlamydial culture from joint tissue (22)(23)(24), many investigators have been unable to reproduce these results (8,25); such failures have led to the conclusion that antigenic debris, but not intact organism, is involved in the reactive arthritis (2,3). However, clinical laboratory methods currently used to screen for chlamydia detect only phenotypic characteristics of the organism (infectivity, antigens) or host immune responses, and both of these can vary according to the biologic state of the organism, which may account in part for the low sensitivity of such methods (26).…”