The utility of lung biopsy in recipients of stem cell transplantation.

BACKGROUND/PURPOSE: Pulmonary infiltrates in recipients of stem cell transplantation often present as diagnostic dilemmas. Although lung biopsy may establish the diagnosis of parenchymal disease, it remains unclear whether such a procedure results in a significant change in the patient's treatment and outcome. This study evaluates the efficacy of lung biopsy in recipients of stem cell transplantation. METHODS: The medical records of 15 stem cell transplant recipients who underwent 18 lung biopsies were reviewed. The indications for stem cell transplantation were leukemia in 10 patients, lymphoma in 2, histiocytosis in 1, neuroblastoma in 1, and Ewing's sarcoma in 1. The results of the lung biopsies were correlated to the clinical management and outcomes. RESULTS: The overall mortality rate was 67% (10 patients). Eight of the 9 patients who required mechanical ventilatory support at the time of lung biopsy died. The pathologic diagnoses were pneumonitis in 6 biopsies, fibrosis in 6, brochiolitis obliterans organizing pneumonia in 3, hemorrhage in 2, and infarction in 1. Therapy was changed in 1 patient who improved after a course of steroids for bronchiolitis obliterans organizing pneumonia. Lung biopsy cultures were positive in 6 patients but rarely resulted in changes in antibiotic therapy. CONCLUSIONS: Results of very few lung biopsies performed in stem cell transplant recipients redirected therapy. Furthermore, the ultimate outcome of these patients were not improved by the results of lung biopsies.

CD4+CD25+ cells regulate CD8 cell anergy in neonatal tolerant mice.

BACKGROUND: Injection of neonatal BALB/c mice with semi-allogeneic splenocytes leads to antigen-specific tolerance lasting into adulthood. Tolerant mice accept A/J skin grafts and fail to generate CD8 cytotoxic T lymphocyte (CTL) activity against A/J targets. Anergic CD8 T cells are present in tolerant mice, and CD4 regulatory cells function to maintain CD8 cell anergy. METHODS: Neonatal BALB/c mice were injected with 108 live CAF, splenocytes, and mice were deemed tolerant by accepting A/J grafts over 40 days. CD8 cell proliferation was measured by in vitro incorporation of bromodeoxyuridine coupled with fluorescence-activated cell sorter analysis. Alloantigen-specific cytotoxicity was tested using 51Cr release assays of A/J or third-party targets. RESULTS: We demonstrate that A/J-specific anergic CD8 cells are present in neonatal primed mice that develop tolerance but not in neonatal primed mice that reject A/J skin grafts. Anergic CD8 cells show decreased proliferation and no CTL activity against A/J targets. Addition of interleukin-2 (IL-2) to unfractionated cultures fails to restore CTL activity against A/J targets. However, addition of IL-2 to CD4-depleted cultures restores A/J-specific CD8 CTL activity. Removal of CD4+/CD25+ cells, but not CD4+/CD25- cells, also restores CD8 CTL activity against A/J in the presence, but not the absence, of IL-2. Moreover, when added back into cultures, purified CD4+/CD25+ cells from tolerant mice inhibit the generation of CD8 CTL against A/J targets. CONCLUSION: These data indicate that CD8 anergy is associated with the state of tolerance, and that CD4+CD25+ cells from tolerant mice function to maintain A/J-specific CD8 cell anergy in vitro.

Balancing the immune system for tolerance: a case for regulatory CD4 cells.

In the past, tolerance mechanisms have focused on processes that involve elimination (deletion) or paralysis (anergy) of immune responses. It is now becoming clearer that peripheral tolerance to antigen depends on the generation of regulatory cells that function to maintain the tolerant state. The development of peripheral tolerance may require that the immune system utilize several strategies, including deletion, anergy, and immunoregulatory pathways, and these strategies may overlap. Recent investigations using animal models of transplantation tolerance have demonstrated that immunoregulatory CD4 mechanisms may play a central role in limiting organ-destructive immune responses. In this Overview, we discuss the rationale behind the need for invoking active regulatory mechanisms in peripheral immunologic tolerance and summarize the data that support or refute a CD4 regulatory mechanism.

Association between enhanced Th2/Th1 cytokine profile and donor T-cell chimerism following total lymphoid irradiation.

Total lymphoid irradiated (TLI) mice develop antigen specific tolerance if the initial antigen exposure occurs shortly after the completion of TLI. We injected TLI-treated mice with semiallogeneic donor cells at 2, 7, or 28 days after completing TLI and determined the levels of donor CD4 and CD8 cells 5 to 7 weeks after TLI treatment. The level of chimerism correlated with the timing of the initial alloantigen exposure. Donor CD4 and CD8 cells were noted only in day 2 or 7 injected mice. Because donor cell chimerism suggested increased in vivo survival of donor cells, we used the level of donor cell chimerism as a surrogate marker for tolerance to examine the relationship between the development of tolerance and enhanced Th2/Th1 cytokine responses to donor antigen. Increased levels of donor CD4 and CD8 cells in the TLI-treated mice was associated with increased Th2/Th1 cytokine production and decreased CTL activity to donor antigen in vitro. Higher Th2/Th1 cytokine levels also correlated with lower CTL activity. The results indicate that the increased production of Th2/Th1 may function to enhance survival of donor cells in TLI-treated mice and suggest that tolerance induction after TLI treatment involves immunoredirection.

The role of interleukin-4 in the induction phase of allogeneic neonatal tolerance.

We previously reported that prolonged graft survival in neonatally tolerant mice was associated with enhanced Th2/Th1 cytokines. To determine whether Th2 CD4 cells function in tolerance, we examined whether we could prevent tolerance by blocking Th2 CD4 maturation, using anti-interleukin (IL)-4 monoclonal antibody treatment during neonatal antigen exposure. Anti-IL-4 treatment restored the ability BALB/c of mice to reject A/J skin grafts and blocked the induction of tolerance through multiple mechanisms. Anti-IL-4 treatment blocked the development of donor microchimerism and recovered the ability of mice to proliferate and to generate appropriate delayed-type hypersensitivity (DTH) and cytotoxic T lymphocyte (CTL) responses against A/J in a dose-dependent manner. Low-dose anti-IL-4 recovered DTH responses and interferon (IFN)-gamma production, but failed to completely prevent IL-4 production or to recover the CTL activity. No A/J-reactive IFN-gamma-producing CD8 cells were detected in these mice. In contrast, mice treated with higher doses of anti-IL-4 generated normal CTL responses against A/J, and contained A/J-reactive IFN-gamma-producing CD8 cells. The recovery of CTL responses and IFN-gamma-producing CD8 cells was associated with a more complete blocking of Th2 cytokine production. Therefore, the presence of IL-4 may play an important role in the induction of neonatal tolerance by shifting maturation of CD4 cells toward Th2 cells and away from Th1 cells, and also by preventing maturation of alloreactive CD8 CTL cells.

Mechanisms of tolerance induction: splenocytes from total lymphoid irradiated mice inhibit the IL-2 pathway in TCR-activated CD4 cells.

Mice given total lymphoid irradiation (TLI) can be tolerized by an incompletely understood mechanism to foreign Ags given during a brief window of time immediately after completing radiation. We previously showed that splenocytes taken from mice immediately after completing TLI treatment (TLI cells) block the ability of control cells to proliferate or to produce IL-2 in response to alloantigen, suggesting that TLI cells interfere with the IL-2 pathway in responder lymphocytes. To further characterize the mechanism by which TLI cells affect IL-2, we utilized an in vitro system of T cell activation. Adding TLI cells into cultures decreased the ability of TCR-stimulated T cells to proliferate and to secrete IL-2 by 40 to 60%. Exogenous IL-2 did not restore the proliferative response. The inhibition of IL-2 secretion resulted both from a decrease in the number of IL-2-producing cells and a decrease in IL-2 mRNA transcription. TLI cells directly inhibited IL-2 secretion by TCR-stimulated CD4 cells, as determined by ELISPOT. Competitive PCR demonstrated that TLI cells decreased IL-2 transcription of TCR-stimulated CD4 cells by 75%. In situ hybridization confirmed that unfractionated spleen and sorted CD4 cells from TCR-stimulated cultures transcribed less IL-2 RNA in the presence of TLI cells. The results show that TLI cells directly inhibit IL-2 transcription and protein secretion of normal TCR-stimulated CD4 cells.

Alloantigen priming after total lymphoid irradiation alters alloimmune cytokine responses.

Total lymphoid irradiation (TLI) treatment represents a model of acquired tolerance, as TLI-treated mice develop donor-specific tolerance when exposed to alloantigens shortly after completing TLI. To determine whether immunoredirection plays a role in immunologic tolerance in TLI, we examined whether antigen priming in the immediate post-TLI stage altered the cytokine profile toward Th2. Compared with splenocytes isolated from control primed mice, the splenocytes from TLI-primed mice failed to proliferate to immunogen in mixed leukocyte reaction cultures but proliferated normally to third-party alloantigen. Whole spleen and purified CD4 cells isolated from TLI-primed mice produced more interleukin (IL)-4 and less gamma-interferon (IFN-gamma) in response to immunogen-bearing stimulator cells than controls, resulting in higher IL-4 to IFN-gamma ratios. The CD4 subset from TLI-primed mice contained more IL-4-producing and fewer IFN-gamma-producing cells, suggesting that priming after TLI shifted CD4 maturation toward Th2 cells. Surprisingly, TLI-primed mice contained no immunogen-responsive, IFN-gamma-producing CD8 cells, indicating that priming after TLI abrogated development of this CD8 subset. In summary, the data show that priming in the immediate post-TLI phase shifts the allospecific memory cytokine pattern toward Th2 cytokines by enhancing IL-4-producing CD4 cells and preventing maturation of IFN-gamma-producing CD8 cells. We speculate that the cytokine milieu at the time of antigen priming drives differentiation of the tolerogen-specific immune response toward Th2 cells, because splenocytes isolated immediately after TLI produced high levels of IL-4 and little IL-2. The enhanced Th2 pattern that developed in the TLI-primed mice suggests that immunoredirection may also occur in the TLI model of tolerance.

Trends in pediatric trauma management.

Injuries are the leading cause of death in children 1 to 14 years old and result in permanent disabilities for thousands of children each year. Blunt trauma accounts for more than 60% of childhood injuries. Head trauma is most common, but the most severely injured children have multisystem injuries, frequently of the extremities, chest, and abdomen. The child's response to injury differs from that of the adult, and specific patterns are seen with blunt injury; recognition of these patterns is essential for proper management. The general surgeon coordinates the total care of the injured child, including the efforts of a variety of medical specialists, to provide cohesive and efficient care.

Congenital diaphragmatic hernia in an era of delayed repair after medical and/or extracorporeal membrane oxygenation stabilization: a prognostic and management classification.

In November 1987 we began to practice delayed repair of acutely symptomatic congenital diaphragmatic hernia (CDH) following medical and/or extracorporeal membrane oxygenation (ECMO) stabilization. We reviewed 23 consecutive patients with CDH symptomatic at birth treated over the ensuing 2 1/2 years. The mean age at admission, age at repair, and interval from admission to repair were 4.9, 37.0, and 32.6 hours, respectively. Overall survival was 52% (12/23). ECMO was used in 14 patients with 7 survivors (50%); 4 of these patients underwent repair prior to ECMO and 10 while on ECMO. The patients were retrospectively grouped into three classes based on postductal arterial blood gas (ABG) response to conventional medical management: class A (n = 8), able to achieve and sustain adequate oxygenation (PO2 greater than 60 mm Hg) and hyperventilation (PCO2 less than 40 mm Hg); class B (n = 10), unable to sustain adequate oxygenation (PO2 less than 60 mm Hg) but able to be hyperventilated (PCO2 less than 40 mm Hg); and class C (n = 5), unable to be oxygenated (PO2 less than 60 mm Hg) or hyperventilated (PCO2 greater than 40 mm Hg). The interval from admission to repair was 13.6, 53.5, and 25.4 hours for classes A, B, and C, respectively. Two class A (25%), nine class B (90%), and three class C patients (60%) were placed on ECMO. Survival rates were 88%, 50%, and 0% for classes A, B, and C, respectively. We propose the following management protocol. Class A patients are stable and can be repaired at any convenient point after admission without prerepair ECMO; few will need it afterward.(ABSTRACT TRUNCATED AT 250 WORDS)

Altered IFN-gamma and IL-4 pattern lymphokine secretion in mice partially depleted of CD4 T cells by anti-CD4 monoclonal antibody.

Complete elimination of CD4 cells by in vivo treatment with anti-CD4 mAb may result in B cell polyclonal activation. Additionally, mice treated with doses of anti-CD4 that eliminate half the CD4 cells produced higher anti-SRBC antibody responses than controls. This suggests that partial CD4 depletion enhances Th2-like function. To test this hypothesis we examined Th1 and Th2 lymphokine potential in mice partially depleted of CD4 cells. We measured IL-4 and IFN-gamma secretion by stimulated unfractionated spleen cells and analyzed activated, purified CD4 cells by RNA in situ hybridization to determine the percentage of IFN-gamma- or IL-4-producing cells. Unfractionated splenocytes from partially CD4-depleted mice secreted more IL-4 and less IFN-gamma than splenocytes from control mice. In situ hybridization proved that CD4 cells from partially depleted mice contained a higher percentage of IL-4 and a lower percentage of IFN-gamma-producing cells than controls. These results indicate that treatment with a dose of mAb resulting in partial CD4 depletion may permit increased Th2-like lymphokine expression. This study also provides evidence that cells committed to Th2-like function exist in vivo in mice.

Improvement in survival of patients with congenital diaphragmatic hernia utilizing a strategy of delayed repair after medical and/or extracorporeal membrane oxygenation stabilization.

Patients with congenital diaphragmatic hernia (CDH) symptomatic at birth treated at this institution over the past 6 years were reviewed. The patients were divided into two chronological groups for analysis: group 1, consisting of 15 patients treated from January 1984 through October 1987, a period during which acute CDH was considered to be a surgical emergency; and group 2, comprising 20 patients treated from November 1987 through October 1989 using a management protocol of delayed repair following medical and/or extracorporeal membrane oxygenation (ECMO) stabilization. These two groups did not differ significantly in gestational age, birth weight, Apgar scores, hernia side, or age at admission. Group 2 had a longer mean interval from admission to repair (26.5 v 1.8 h, P = .01) and average age at repair (31.0 v 6.5 h, P = .02) than did group 1. Prosthetic closure of the diaphragmatic defect was required more frequently in group 2 then in group 1 (63% v 31%, P = .07). Survival in group 2 was significantly greater than in group 1 (55% v 20%, P = .04). Seven group 2 patients (35%) achieved a prerepair or pre-ECMO PO2 greater than 100 mm Hg and all survived; four of the 13 "nonresponders" also survived. ECMO was used in 11 group 2 patients with five survivors (45%); four of these patients underwent repair prior to ECMO and seven underwent repair while on ECMO.(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled trial of corticosteroids in children with corrosive injury of the esophagus.

BACKGROUND: It is controversial whether treatment with corticosteroids reduces stricture formation in the esophagus after the ingestion of caustic material. METHODS: We conducted a prospective study over an 18-year period in which 60 children (median age, 2 years) with esophageal injury from the ingestion of caustic material were assigned randomly to treatment either with or without corticosteroids. The corticosteroids were given initially as prednisolon (2 mg per kilogram of body weight per day intravenously) and then as prednisone orally to complete a three-week course. All patients were evaluated by esophagoscopy within 24 hours of the ingestion. Those with moderate or severe esophageal injury had repeat esophagoscopy and barium swallow at follow-up. RESULTS: Esophageal strictures developed in 10 of the 31 children treated with corticosteroids and in 11 of the 29 controls (P not significant). Four children in the steroid group and seven in the control group eventually required esophageal replacement (P not significant). All but 1 of the 21 children with strictures had severe circumferential burns on initial esophagoscopy. CONCLUSIONS: There appears to be no benefit from the use of steroids to treat children who have ingested a caustic substance. The development of esophageal stricture was related only to the severity of the corrosive injury.

Hemangioma in a lymph node.

Hemangiomas occurring in lymph nodes are extremely rare and, to our knowledge, have been documented in the literature only once previously. We report an additional case that was found incidentally in a patient who had undergone a right hemicolectomy and small-bowel resection for widespread angiodysplasia. In addition, the patient also had a third type of vascular lesion, namely, a hemangiopericytoma of the oral mucosa. We also reviewed the literature regarding vasoformative lesions occurring in lymph nodes.

Necrotizing fasciitis: a preventable disaster.

Twenty-eight cases of necrotizing fasciitis (NF) were treated in 27 patients. Most commonly these infections were caused by perineal disease, operative procedures, and cutaneous ulcers. Associated chronic diseases were present in 21 patients. Postoperative fasciitis occurred when prophylactic antibiotics were omitted or used inappropriately during clean-contaminated or contaminated procedures and when primary skin closure was done in the presence of intra-abdominal contamination. All but four infections were polymicrobial. The overall mortality rate was 73% (20 of 27). Death was due to persistent would sepsis in nine, systemic septic complications despite apparent local control of the infection in nine, and myocardial infarction in two patients. Five of seven survivors had NF limited to one region (leg, perineum, or abdomen). Only 2 of 15 patients survived when more than one debridement was necessary to control ongoing wound necrosis. Eleven of 12 patients who had a delay in treatment for more than 12 hours died. These results suggest that prompt recognition and treatment of NF are essential for survival. The presence of chronic debilitating diseases may contribute to the uncontrollable nature of both local and systemic infection, further emphasizing the need for early diagnosis. Postoperative fasciitis is potentially preventable by strict adherence to the principles for management of contaminated procedures.