- Many experts believe that host response is involved in the pathogenesis of CSD and is responsible for the clinical manifestations rather than the direct effect of B. henselae. The absence of viable organisms in affected lymph nodes (in the presence of positive PCR for B. henselae DNA), and the fact that arthritis, arthralgia and erythema nodosum (that are often associated with autoimmune diseases) have been described in CSD, support this concept.