Calcium pyrophosphate dihydrate crystal deposition and other crystal deposition diseases.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease continues to be of intense clinical and basic science interest. Follow-up of studies of hereditary CPPD crystal deposition indicate differences from the common sporadic disease. The results of a prospective study of CPPD crystal deposition arthropathy confirm that clinical symptoms appear to be independent of radiologic progression. Novel clinical presentations include association with pregnancy and simulation of meningitis. CPPD crystal deposition pathology in synovium ultrastructurally resembles that in cartilage. Factors such as the presence of ATP can induce experimental calcifications in tissue culture that resemble CPPD crystal deposition. Interleukin-8 and tyrosine phosphorylation of neutrophil protons can mediate CPPD crystal deposition-associated inflammation. The control of crystal function and dissolution recently has been the subject of many general reviews. The theory outlined in these papers is important for understanding CPPD crystal deposition and basic phosphate crystal formation and dissolution.