Systemic inflammatory response syndrome and acute renal failure associated with Hemophilus influenzae septic meningitis

Haemophilus influenzae porin induces Toll-like receptor 2-mediated cytokine production in human monocytes and mouse macrophages

The production of proinflammatory cytokines is likely to play a major pathophysiological role in meningitis and other infections caused by Haemophilus influenzae type b (Hib). Previous studies have shown that Hib porin contributes to signaling of the inflammatory cascade. We examined here the role of Toll-like receptors (TLRs) and the TLR-associated adaptor protein MyD88 in Hib porin-induced production of tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6). Hib porin-induced TNF-alpha and IL-6 production was virtually eliminated in macrophages from TLR2- or MyD88-deficient mice. In contrast, macrophages from lipopolysaccharide (LPS)-hyporesponsive C3H/HeJ mice, which are defective in TLR4 function, responded normally to Hib porin. Moreover anti-TLR2 antibodies but not anti-TLR4 antibodies significantly reduced Hib porin-stimulated TNF-alpha and IL-6 release from the human monocytic cell line THP-1. These data indicate that the TLR2/MyD88 pathway plays an essential role in Hib porin-mediated cytokine production. These findings may be useful in the development of alternative therapies aimed at reducing excessive inflammatory responses during Hib infections.

Epstein-Barr virus-associated acute renal failure: diagnosis, treatment, and follow-up

We retrospectively reviewed our experience of Epstein-Barr virus (EBV)-associated acute renal failure. Of 165 previously healthy children hospitalized with serologically proven primary EBV infection, 8 had acute renal failure, of whom 5 (group A) did not have virus-associated hemophagocytic syndrome (VAHS), while 3 (group B) did have VAHS. All had complications in four or more organ systems. Two patients in group A had renal biopsies showing acute tubulointerstitial nephritis, and the clinical and laboratory findings in the other 3 group A patients were consistent with acute tubulointerstitial nephritis. Acyclovir was used in 1 patient, but she died of hepatic failure and pulmonary hemorrhage. The other 4 spontaneously recovered renal function after supportive care, including hemodialysis in 1 patient. Our experience does not support the routine use of corticosteroids or antiviral agents in these patients. Children in group B had a relatively normal urinalysis. Renal biopsies were not performed, but their presentations were compatible with acute tubular necrosis. We conclude that EBV should be considered as a possible etiological agent in all children presenting with acute renal failure of unknown cause. The diagnosis depends on a high index of suspicion and careful serological evaluation in atypical cases.

Hemophagocytic syndrome in children: an important diagnostic consideration in fever of unknown origin

To study the evolution of hemophagocytic syndrome (HPS) in children, we performed a retrospective review of 19 patients (median age, 17.4 months) in whom an infectious diseases consultation was requested at Texas Children's Hospital during the period of September 1991 through September 2001. Clinical findings consistent with HPS most frequently presented during days 6-14 of illness, concomitant with laboratory abnormalities. Fever was present for a median of 19 days before the diagnosis of HPS. Elevated serum lactate dehydrogenase and ferritin levels were noted in all patients. An infectious agent was identified in 42% of patients; 16% were found to have immunologic or vasculitic disease. HPS is a rare but often fatal disease that can initially present as fever of unknown origin with varying clinical findings, and it can be recognized by physicians who are familiar with the evolution of HPS. It is likely that many of these cases remain undiagnosed because of the HPS's rapidly fatal course.