Macrophage reactions in septic arthritis.

With the aid of monoclonal antibodies, macrophages can be split into functionally distinct subpopulations on the basis of their phenotype. Absence of macrophage subtypes has been noted in chronic inflammatory processes, e.g.

Alteration in the pattern of macrophage subtypes in chronic osteomyelitis compared with acute joint infection.

Macrophage subtypes were detected in cryostat sections of biopsies from patients with chronic osteomyelitis, acute joint infections and normal bone marrow, using monoclonal antibodies against different macrophage populations. The resident macrophage subtype 25F9, the gluco-corticoid-inducible macrophage RM 3/1 and the inflammatory type 27E10 were found in abundance in acute infections. They were also present in tissue sections of uninflamed bone marrow.

PMN elastase in bone and joint infections.

PMN (polymorphonuclear neutrophil) elastase is a proteolytic enzyme which is a biochemical marker for abnormal granulocyte stimulation. In inflammation and sepsis, excessive neutrophil stimulation results in significant amounts of PMN elastase being released into the plasma which indicates the severity of the disease and its prognosis. In 62 patients with osteomyelitis or suppurative arthritis, PMN elastase had a diagnostic sensitivity of 81%, which is comparable to the nonspecific erythrocyte sedimentation rate.

[Suppression of macrophage subpopulations in post-traumatic osteomyelitis].

Similar to other chronic inflammatory diseases such as rheumatoid arthritis the distribution of macrophage subtypes seems to be disturbed in post-traumatic osteomyelitis. This atypical distribution is clearly locally restricted in osteomyelitis. 27E10-positive macrophages found only during the acute phase of inflammation were reduced in 39%, the 25F9-positive subtype, predominating in the late stage of inflammation, was missing in 33%.

[Lymphocyte defects in chronic osteomyelitis. A prospective study].

In patients with chronic post-traumatic osteomyelitis, several deficits in immunological response were demonstrated. In a prospective trial of 20 patients with proven osteomyelitis, histological analysis of lymphocyte subsets in peripheral blood and in the infected bone tissue was performed. The effects of chronic osteomyelitis on lymphocyte subsets in the peripheral blood and in inflamed tissue were only slight.