Hemorrhagic shock impairs mucosal immunity to gut-derived antigens.

Secretory immunoglobulin A (sIgA) is the principal antibody protecting against pathogens in the respiratory tract and other mucosal surfaces. Nosocomial pneumonias are frequent after injury and critical illness and are often due to enteric pathogens. The aim of this study was to assess the relative effect of hemorrhagic shock (HS) on mucosal immunity at intestinal and respiratory mucosal sites. Fisher rats were immunized intragastrically with dinitrophenylated (DNP) Pneumococcus (Pn). Three weeks later, animals were subjected to sham treatment or HS. The animals were then rechallenged with DNP-Pn 1 or 3 days later. Animals were sacrificed 7 days later, and bronchoalveolar and gastric lavage was performed. Total and anti-DNP-specific sIgA were quantitated from these secretions by enzyme-linked immunosorbent assay. There was a significant decrease in DNP-Pn-specific sIgA at 72 hours after HS, which was not present in animals at 24 hours after HS. This was most profound in bronchoalveolar lavage specimens. We conclude that impaired mucosal defense against gut-derived antigens after HS may be important mechanistically for the development of posttraumatic pneumonia and other mucosally related infectious complications.

CD4 cell counts as a prognostic factor of major abdominal surgery in patients infected with the human immunodeficiency virus.

OBJECTIVE: To measure the prognostic utility of helper T-cell (CD4) counts in human immunodeficiency virus (HIV)-infected patients undergoing major abdominal surgery. DESIGN: Retrospective case series. SETTING: Three university-affiliated hospitals. PATIENTS: Forty-three HIV-infected patients undergoing major abdominal surgery. MAIN OUTCOME MEASURES: Morbidity and mortality rates with respect to CD4 cell counts. RESULTS: Nineteen of 32 patients who had CD4 cell counts less than 0.20 X 10(9)/L (200 cells/microL) suffered major complications compared with 2 of 11 patients who had CD4 cell counts greater than 0.20 x 10(9)/L (200 cells/microL) (P=.03). Perioperative mortality was 38% for patients with CD4 cell counts less than 0.20 x 10(9)/L, and was 9% for those with CD4 cell counts greater than 0.20 x 10(9)/L (P=.13). Six months postoperatively, mortality rates were 47% and 9%, respectively (P=.03). Of patients with septic processes perioperatively (n=12), mortality was 75%, and was 19% (P=.009) for those with nonseptic processes (n=31). Nine patients had HIV-related intra-abdominal pathologic conditions at laparotomy. Mortality was 56% perioperatively (P=.13) and 88% after 6 months (P=.001). Sixty-eight percent of patients who received blood product transfusions developed complications, whereas only 7% of those who did not receive transfusions developed complications (P<.001). Overall mortality and morbidity rates were 37% and 49%, respectively. Patients with morbidity had lower CD4 cell counts (median, 0.034 x 10(9)/L) than those without complications (median, 0.102 x 10(9)/L) (P=.02). Similarly, patients who died had lower CD4 cell counts (median, 0.031 x 10(9)/L vs 0.088 x 10(9)/L) (P=.05). CONCLUSIONS: Patients with acquired immunodeficiency syndrome-defining CD4 cell counts undergoing major abdominal surgery developed more complications and had poorer outcomes at 6-month follow-up compared with HIV-infected patients whose CD4 cell counts were greater than 0.20 x 10(9)/L (200 cells/microL). A perioperative septic process and HIV-related pathologic conditions seen at laparotomy are also associated with worse outcomes.

Nasal-associated lymphoid tissue is an inductive site for rat tear IgA antibody responses.

The role of nasal-associated lymphoid tissue (NALT) as a mucosal inductive site for tear IgA antibody responses was investigated in the rat model. Fluorescent microspheres were shown to access and be taken up by NALT after intranasal of ocular-topical administration, although fewer microspheres were found in the latter case. Tear IgA anti-DNP antibody responses to dinitrophenylated Streptococcus pneumoniae were 6 micrograms/ml at day 7, 10 micrograms/ml at day 10, and were still detectable on day 21 (5 micrograms/ml) following ocular or gastrointestinal immunization. Intranasal immunization induced tear IgA responses which were 1.7-fold higher at day 7 (10 micrograms/ml), peaked by day 10 (14 micrograms/ml) and were still 1.6-fold higher (8 micrograms/ml) at day 21 than responses of ocular or gastrointestinal groups. These findings suggest that intranasal immunization may be more effective than ocular or gastrointestinal administration in eliciting tear IgA antibody responses and, taken together with the microsphere data, indicate that NALT can serve as an inductive site for ocular mucosal IgA responses.