Immunocompromised persons opportunistic infections,

Immunocompromised A condition in which the immune system is not functioning normally. This condition is seen in the very young, the very old, human immunodeficiency virus-infected individuals, and in transplant patients. An immunocompromised person is susceptible to opportunistic infections. 

Progressive multifocal leukoencephalopathy (PML) is historically a rare demyelinating disease that is usually associated with disorders of the reticuloendothelial system, neoplasias and immunosuppressive therapy [1, 2]. However, it has become more important in clinical medicine because it is frequently seen as an opportunistic secondary infection in immunocompromised persons with AIDS. PML is characterized by focal lesions that are noninflammatory and caused by infection of oligodendrocytes with the JC papovavirus. 

The list of opportunistic infections and cancers mentioned before only covers the most commonly encountered diseases. Numerous other infections are also seen at lower frequency. These diseases are only a fraction of potential diseases that could affect immunocompromised persons, as HIV destroys only certain parts of the immune system. 

The esters also react readily with aryl hydrazines to give aryl hydrazone derivatives. Examples of the latter were first synthesized (prior to the availability of tetraalkyl carbonylphosphonates) from tetraalkyl methylenebisphosphonates and aryl diazonium salts, analogously to the phosphonoglyoxylate hydrazone synthesis described in a previous section. First made as possible precursors in a ketone synthesis, several of these compounds, converted to free acid salts by treatment with BTMS followed by dicyclohexylamine in methanol, proved to have unexpected inhibitory activity vs the pyrophosphate-dependent phospho-fructokinase of the parasite T. gondii, which causes a potentially lethal opportunistic infection in immunocompromised persons such as AIDS patients [94]. In fact, the 2,4-dinitrophenylhydrazone of carbonylbisphosphonic acid (as the tetrasodium salt) dramatically abated toxoplasmosis lesions in infected human foreskin fibroblasts [94]. Animal toxicity in this compound, probably arising from in vivo hydrolysis to the highly toxic hydrazine, precluded its future development, but the result remains an interesting lead. 

---