The Medical clinics of North America
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Histocompatibility typing has assumed an increasingly important role as a clinical and research tool in rheumatic diseases. The HLA antigens which are serologically defined (A and B series) are being used most extensively for clinical work, but the role of other immunologic determinants in the HLA complex is being evaluated. These include D-locus (MLC) determinants, several complement components, and immune response genes which have been well characterized in the mouse, but not in man. ⋯ Its value as an indicator of prognosis, and its value in counselling family members is not well established. There are many interesting hypotheses regarding pathogenetic mechanisms of these rheumatic diseases based on susceptibility factors related to the major histocompatibility complex. An abnormal immune response gene within the complex is probably a key feature of the mechanism, but the exact details are little more than speculative at this point.