Pustular psoriasis and aseptic purulent arthritis: possible role of leukotrienes B4 and C4 in a flare of synovitis.

BACKGROUND

Arthritis is a frequent complication of pustular psoriasis. However, the mechanism of onset of this arthritis still remains unclear.

OBJECTIVES

The present study was conducted to determine whether leukotriene (LT) B4 or LTC4 is one of the proinflammatory mediators that possibly enhance exacerbation of the arthritis lesions.

METHODS

We investigated the condition of the arthritis and autopsy findings of two cases of generalized pustular psoriasis with the severe complication of aseptic purulent arthritis. We also measured the synovial fluid levels of LTB4 and LTC4 by radioimmunoassay.

RESULTS

The collected synovial fluid was purulent, but nonbacterial, and the synovium of the knee joint showed histopathologic evidence of polymorphonuclear leukocyte (PMN) invasion, edema and dilatation of small vessels showing similarity to a histologic reaction in the skin lesions. The immunoreactive (i-) LTB4 and i-LTC4 in the samples significantly exceeded the amount measured in osteoarthritis patients used as the controls.

CONCLUSION

Thus, i-LTB4 and i-LTC4 appear to be generated in the arthritis lesions of pustular psoriasis, the former attracting PMNs to the joints and the latter causing exudation of synovial fluid.