To investigate the prognostic role of tumour ne-It is a major public health problem in several parts of crosis factor (TNF) in Japanese encephalitis virus Southeast Asia including India . (JEV) infection, we measured the immunoreac-
The mortality in this acute encephalitic illness has vartive forms of TNF concentrations in the serum ied from 20 to 40% during different epidemics in India and cerebrospinal fluid (CSF) of 47 laboratorywith an average of 30% [Rodrigues, 1984]. The morbidconfirmed cases of JE. It was observed that TNF ity amongst survivors is also high, nearly half the survilevels were elevated (ΟΎ15 pgm/ml) in all the 47 vors exhibiting neuropsychiatric sequelae [Gourieserum samples (range 19.4-923.8 pg/ml), while . in 46/47 CSF samples TNF was elevated (range
The role of tumour necrosis factor (TNF) in the host 10.8-376 pg/ml). The mean (SD) TNF levels in the response to infection and injury is the subject of intense serum of fatal cases was 234.34 pg/ml (304.40) investigation. TNFβ£ is a 17-kDa cytokine that is rapidly as compared to the mean of 85.31 pg/ml (SD produced in response to infectious stimuli and appears 153.92) in nonfatal cases. Similar observations to be pivotal for induction of other endogenous mediawere also made with respect to the TNF levels tors as well as for initiation of several systemic rein the CSF; the mean of fatal cases was 69.39 pg/ sponses to infection . In viral ml (SD 39.00) in contrast to the mean of 62.41 infections, TNF plays a key role in a variety of specific pg/ml (SD 75.25) of nonfatal cases. The increase processes ranging from promoting viral replication and in TNF levels did not show any correlation to the evasion of host defenses to regulating the humoral and duration of illness. It was further observed that cellular antiviral immune response . the mortality rate increased with increasing con-Consequently, this cytokine appears to be an important centrations of TNF in the serum and CSF. Correladeterminant of the clinical outcome during infection tion of laboratory parameters to final outcome even with moderate release altering the immune and revealed that TNF concentrations above 50 pg/ metabolic function in a manner appropriate to combatml in serum correlated significantly (P Ο .05) with ing invading organisms. In contrast, exaggerated or a fatal outcome, whilst high levels of JEV-IgM prolonged secretion of TNF has been implicated in the antibodies (ΟΎ500 units) in the CSF correlated with pathogenesis of significant morbidity in diseases like a nonfatal outcome (P Ο .03). These results sugcerebral malaria, septic shock, bacterial meningitis, gest that TNF can be used as a possible prognosleprosy, and other noninfectious conditions [Fong and ticator of a fatal outcome in JEV infection.