The heat shock proteins (hsp) are regarded as being immunogenic to the animal hosts. Although certain hsp are suggested to be expressed on the cell surface, further evidence for the cell surface expression of these proteins has been required. In this article we report the development of a MAb NT22. This antibody reacted with ATP-binding proteins (which contain a large amount of 70-kDa hsp family) of HeLa cells, and with purified bovine 70-kDa hsp. It did not react with the E. coli lysate, but clearly reacted with the recombinant rat hsc73. However, NT22 failed to react with hsp72. Furthermore, stress treatment of cells also indicated that considerable amounts of NT22-defined antigen translocated into the nucleus from the cell cytoplasm. These results suggest that NT22 is a novel MAb that reacts specifically to the mammalian hsc73. Moreover, this antibody could detect the constitutive and stress-induced cell surface expression of its relevant antigen. It is expressed preferentially on EBV-transformed B cell and certain epithelial cancer cell lines. However, resting B cells did not express this antigen on the cell surface. These data indicate that hsc73 could be expressed on the cell surface of certain cells, and suggest that hsc73 may interact with the host immune system.

A 67-year-old man was referred to the Department of Internal Medicine at Tokyo Medical University with interstitial pneumonia in July 1999. He presented with keratotic plaques on both palsm and on the ventral and lateral sides of his fingers. Erythematous keratosis was observed on the dosal aspect of his fingers and metatarsophalangeal (MP) joints. Edematous erythema was seen on the patient's chest, back, and the extensor surfaces of his arms. Electromyography revealed a myogenic pattern and an increased level of myogenic enzymes was found in the blood. Histological findings of the ventral sides of his fingers showed hyperkeratosis and parakeratosis of the dermal tissue and liquefaction degeneration of the basal layer at the papilla. Based on these findings, the patient was given a diagnosis of dermatomyositis associated with mechanic's hand. A systemic examination confirmed interstitial pneumonia and carcinoma of the duodenal papilla. Mechanic's hand is a type of dermatitis associated with myopathy first reported by Stahl et al. in patients with collagen disease. We report herein the first documented case of mechanic's hand in Asians.

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We report a case of marked hypocomplementemia and tubulointerstitial nephritis associated with Sjögren's syndrome (SS) in a male patient. Renal biopsy revealed tubulointerstitial nephritis but did not identify specific immune deposits of the tubulo-interstitium. After steroid therapy, the renal failure and hypocomplementemia diminished. Hypocomplementemia without cryoglobulinemia is not commonly observed in SS patients, and hypocomplementemic tubulointerstitial nephritis was strongly suspected. Hypocomplementemic tubulointerstitial nephritis is rare; only one case has been described in the literature. In our case and the previous case, the patients were elderly men, and they had some similar clinical characteristics. Idiopathic hypocomplementemic tubulointerstitial nephritis resembling our case has been reported. These facts suggest that hypocomplementemic tubulointerstitial nephritis may occur in patients with SS, and such cases may not be as rare as once thought because it might be appropriate to include them in the category of idiopathic cases. Such a syndrome should be included in the differential diagnosis of hypocomplementemia.

The association of either thrombotic thrombocytopenic purpura (TTP) or crescentic glomerulonephritis with Sjögren's syndrome is rare. We report a case of TTP appearing after the diagnosis of SjOgren's syndrome with crescentic glomerulonephritis and membranous nephropathy. Circulating immune complex was detected, and immune complex deposits were shown along the capillary walls of renal biopsy specimens. Despite steroid pulse therapy and plasma exchange therapy, the patient died. The etiology of TTP is unclear. This case is important when considering the etiology of TTP related to autoimmune disease.