Immune consequences of nonoperative treatment of splenic trauma in the rat model

To investigate the immunologic consequences of non-operative management of splenic injury, three parameters were studied: survival following pneumococcal sepsis, clearance of blood-borne bacteria, following Hemophilus influenzae challenge, and antibody response to type III pneumococcal capsular polysaccharide. Two hundred twenty-five Sprague-Dawley rats were divided into three groups and subjected either to a splenectomy, a sham operation, or standard blunt trauma. A significant increase in mortality was noted in the splenectomized group as compared with both the traumatized and control groups when challenged with Streptococcus pneumoniae. In both the control and trauma groups, H influenzae cleared significantly within 18 hours. Blood-borne bacteria persisted at the same level for 72 hours in the splenectomized animals. Four and 11 days later, the antibody level in both traumatized and control groups was higher than in the splenectomized subjects (P less than .001). There was no difference in the serum antibody level between the control and trauma groups at four days. However, at 11 days the trauma group showed a significant decrease in the antibody level (P less than .05). It can be concluded that following spontaneously-healing splenic trauma in the rat model, survival, bacterial clearance, and antibody response were all superior to that observed in the splenectomized subjects. In addition, the healed splenic disruption did not impair clearance of blood-borne encapsulated bacteria.     

Pneumococcal vaccine improves pulmonary clearance of live pneumococci after splenectomy

The efficacy of pneumococcal capsular polysaccharide vaccines after splenectomy to decrease the incidence of postsplenectomy pneumococcal sepsis is controversial. We examined the effect of pneumococcal vaccine on clearance of live pneumococci from lungs of splenectomized and sham-operated mice following an aerosol challenge of pneumococci. Splenectomy impaired clearance of pneumococci from mouse lungs and allowed for increased translocation of pneumococci to tracheobronchial lymph nodes compared to shams (P less than 0.01). Pneumococcal vaccine improved lung clearance in both splenectomized and sham-operated mice compared to saline controls (P less than 0.01), but the number of live pneumococci recovered from lung pairs was greater in splenectomized mice compared to shams (P less than 0.01). Pneumococcal vaccination facilitated earlier translocation of pneumococci to tracheobronchial lymph nodes, and probably promoted bactericidal activity in these nodes, in both splenectomized and sham-operated mice. Survival in splenectomized mice was improved by vaccination, but remained significantly less than that in saline-treated sham-operated mice (P less than 0.0009). The data show that pneumococcal vaccine can improve lung antipneumococcal defenses in splenectomized mice, but not to the same degree as in mice retaining their spleens. Pneumococcal vaccine should be given after splenectomy, but surgeons should caution patients that it may be less effective than when given to individuals with intact spleens or before elective surgery.     

Penicillin and natural immunity protect against postsplenectomy sepsis

Prophylactic penicillin, splenic autotransplantation, and immunization using pneumococcal vaccine have all been shown to reduce the incidence and mortality of postsplenectomy sepsis. However, little is known regarding the effect of penicillin in established infection or the effect of prior infection in either asplenic controls or animals with autotransplanted splenic tissue. An animal model with bacterial introduction via the lungs was used to investigate the effect of penicillin, splenic autotransplantation, and previous exposure to the infecting organism on the mortality of postsplenectomy sepsis. One hundred fifty-nine rats underwent either sham celiotomy, intraperitoneal splenic autotransplantation, or splenectomy. Twelve weeks postoperatively all animals were challenged using Streptococcus pneumoniae delivered transtracheally. Half of each group received procaine penicillin by intramuscular injection for 5 days beginning 24 hr post bacterial inoculation and mortality was observed. Eight weeks later surviving rats that had received penicillin were reinoculated with the same organism and mortality was again observed. Splenic autotransplantation reduced the early mortality in postsplenectomy sepsis. Prior bacterial exposure reduced the mortality in postsplenectomy sepsis, even in splenectomized animals. Treatment with penicillin produced a marked reduction in mortality even when administration was postponed for 24 hr after bacterial inoculation.     

Splenic trauma. Choice of management.

The modern era for splenic surgery for injury began in 1892 when Riegner reported a splenectomy in a 14-year-old construction worker who fell from a height and presented with abdominal pain, distension, tachycardia, and oliguria. This report set the stage for routine splenectomy, which was performed for all splenic injury in the next two generations. Despite early reports by Pearce and by Morris and Bullock that splenectomy in animals caused impaired defenses against infection, little challenge to routine splenectomy was made until King and Schumacker in 1952 reported a syndrome of "overwhelming postsplenectomy infection" (OPSI). Many studies have since demonstrated the importance of the spleen in preventing infections, particularly from the encapsulated organisms. Overwhelming postsplenectomy infection occurs in about 0.6% of children and 0.3% of adults. Intraoperative splenic salvage has become more popular and can be achieved safely in most patients by delivering the spleen with the pancreas to the incision, carefully repairing the spleen under direct vision, and using the many adjuncts to suture repair, including hemostatic agents and splenic wrapping. Intraoperative splenic salvage is not indicated in patients actively bleeding from other organs or in the presence of alcoholic cirrhosis. The role of splenic replantation in those patients requiring operative splenectomy needs further study but may provide significant long-term splenic function. Although nonoperative splenic salvage was first suggested more than 100 years ago by Billroth, this modality did not become popular in children until the 1960s or in adults until the latter 1980s. Patients with intrasplenic hematomas or with splenic fractures that do not extend to the hilum as judged by computed tomography usually can be observed successfully without operative intervention and without blood transfusion. Nonoperative splenic salvage is less likely with fractures that involve the splenic hilum and with the severely shattered spleen; these patients usually are treated best by early operative intervention. Following splenectomy for injury, polyvalent pneumococcal vaccine decreases the likelihood of OPSI and should be used routinely. The role of prophylactic penicillin is uncertain but the use of antibiotics for minor infectious problems is indicated after splenectomy.     

Splenectomy versus splenic salvage for spleens ruptured by blunt trauma

Of 339 patients treated in three Charlotte hospitals from January 1960 through March 1983 for splenic rupture caused by blunt trauma, 317 (93.5%) underwent splenectomy, and 22 (6.5%) underwent splenic salvage operations. Perioperative mortality for splenectomized patients was 7.9 per cent, and that for those who received splenic salvage operations was 22.7 per cent. Perioperative sepsis occurred in 4.4 per cent of the splenectomized patients and in 9 per cent of those whose spleens were salvaged. Perioperative deaths and sepsis in both groups were related to associated injuries, not to splenic injuries. Follow-ups from 5 months to 22.4 years (mean, 9.5 years) of the 292 splenectomized patients who survived their injuries show that 252 (86.3%) are living, 22 (7.5%) have died of causes unrelated to splenic injuries, 18 (6.1%) could not be found, and none of the patients traced has died of sepsis. One patient (0.34%) experienced an episode of sepsis i.e., a nonfatal septicemia 7 years postsplenectomy, that may be related to splenectomy. These data suggest that the importance of splenic salvage for prevention of postsplenectomy sepsis has been overemphasized and that expeditious splenectomy remains the procedure of choice for patients with ruptured spleens, especially for those with hypovolemic hypotension, anemia from hemorrhage, or multiple injuries. Data to substantiate these views will be presented.     

Surgical infection society guidelines for vaccination after traumatic injury

BACKGROUND: Recommendations for vaccination of injured patients against infection are evolving. Newly-recognized infections, safety considerations, changing epidemiology, and redefinition of patient groups at risk are factors that may influence vaccine development priorities and recommendations for immunization. However, recommendations must often be formulated based on incomplete data, forcing reliance on expert opinion to address some crucial questions. These guidelines provide evidence-based recommendations for the prevention or treatment of infectious morbidity and mortality after traumatic injury, such as soft tissue wounds, human or animal bites, or after splenectomy. METHODS: A panel of experts conducted a thorough review of published literature, as well as information posted on the internet at the websites of the U.S. Centers for Disease Control and Prevention, among others. MEDLINE was searched for the period 1966-2004 using relevant terms including "anthrax," "rabies," "tetanus," "tetanus toxoid," and " splenectomy," in combination with "vaccine" and "immunization." The Cochrane database was searched also. Reference lists were cross-referenced for additional relevant citations. All published reports were analyzed for quality and graded, with the strength of the recommendation proportionate to the quality of the supporting evidence. RESULTS: Recommendations are provided for pre- and post-exposure prophylaxis of rabies and anthrax. For tetanus prophylaxis, recommendations are provided for prophylaxis of acute wounds stratified y age and prior immunization status, and for immunization of persons at high risk. After splenectomy, it is recommended that all persons ages 2-64 years receive 23- valent pneumococcal vaccine and meningococcal vaccine, with Haemophilus influenzae type B vaccine administered to high-risk patients as well (all are Grade D recommendations). Vaccination should be given two weeks before elective splenectomy (Grade C), or two weeks after emergency splenectomy (Grade D). A booster dose of pneumococcal vaccine is recommended after five years (Grade D); no re- vaccination recommendation is made for meningococcal or Haemophilus influenzae type B vaccine. Recommendations for prophylaxis of splenectomized children under the age of five years are also provided. CONCLUSION: There are limited data on the use of vaccines after injury. This document brings together a disparate literature of variable quality into a discussion of the infectious risks after injury relevant to vaccine administration, a summary of safety and adverse effects of vaccines, and evidence-based recommendations for vaccination.     

Response to immunization after partial and total splenectomy

Survival after infection from Streptococcus pneumoniae in both animals and man is influenced by the amount of splenic tissue. We investigated the effect of differences in splenic weight upon the antibody response to immunization and the effect of immunization upon survival after pneumococcal challenge. Young Sprague-Dawley rats had either sham operation, hemisplenectomy, splenectomy with splenic autotransplantation, or total splenectomy. Nine weeks later, rats were immunized with a heat- and formalin-killed type-specific pneumococcal vaccine. Antibody response measured by radioimmunoassay was similar in all operative groups and was significantly higher than in nonimmune rats (P less than 0.01). Splenic weight was less after hemisplenectomy or autotransplantation than in sham-operated animals (P less than 0.01). Immunization improved survival after live pneumococcal challenge in rats that had autotransplantation and total splenectomy (P less than 0.001). Our results demonstrate that splenic weight does not affect the antibody response to pneumococcal immunization in rats. Immunization improves survival after bacterial challenge in susceptible animals and minimizes the detrimental effect of reduction in splenic mass.     

Relative merits of partial splenectomy, splenic reimplantation, and immunization in preventing postsplenectomy infection.

Partial splenectomy, splenic autotransplantation, and immunization with pneumococcal vaccine have been reported to protect patients against overwhelming postsplenectomy infection, and this study was undertaken to evaluate these therapeutic alternatives. For this purpose 136 rats were divided into experimental groups: 34 controls, 34 splenectomy, 34 partial splenectomy, and 34 splenic autotransplantation animals. Five weeks after operation, two-thirds of the animals were immunized with killed pneumococci. The effects of operation and immunization were studied by challenging the animals intravenously with pneumococci. Pneumococcal antibody titers were determined, and phagocytic uptake of pneumococci by the spleen and liver was measured. Immunization impressively increased the survival rate in all groups. At low-challenge doses autotransplantation prolonged survival. At higher-challenge doses only partial splenectomy increased survival. Partial splenectomy and control animals had higher antibody titers than did splenectomy and autotransplantation rats. Animals with the highest antibody titers had the greatest splenic and hepatic phagocytic uptake of pneumococci. Partial splenectomy was more efficient in removing pneumococci than was autotransplantation. Thus immunization is one of the most important factors contributing to survival after splenectomy. Partial splenectomy is preferable to splenic autotransplantation because it is associated with higher antibody titers after immunization, better pneumococcal splenic uptake, and improved survival rates.     

Die Behandlungspraxis bei Patienten mit isolierter stumpfer Milzverletzung

Background

The non-operative management (NOM) of blunt splenic injuries has gained widespread acceptance. However, there are still many controversies regarding follow-up of these patients. The purpose of this study was to survey active members of the Swiss Society of General and Trauma Surgery (SGAUC) to determine their practices regarding the NOM of isolated splenic injuries.

Materials and methods

A survey of active SGAUC members with a written questionnaire was carried out. The questionnaire was designed to elicit information about personal and facility demographics, diagnostic practices, in-hospital management, preferred follow-up imaging and return to activity.

Results

Out of 165 SGAUC members 52 (31.5%) completed the survey and 62.8% of all main trauma facilities in Switzerland were covered by the sample. Of the respondents 14 (26.9%) have a protocol in place for treating patients with splenic injuries. For initial imaging in hemodynamically stable patients 82.7% of respondents preferred ultrasonography (US). In cases of suspected splenic injury 19.2% of respondents would abstain from further imaging. In cases of contrast extravasation from the spleen half of the respondents would take no specific action. For low-grade injuries 86.5% chose to admit patients for an average of 1.6 days (range 0-4 days) with a continuously monitored bed. No differences in post-discharge activity restrictions between moderate and high-grade splenic injuries were found.

Conclusion

The present survey showed considerable practice variation in several important aspects of the NOM of splenic injuries. Not performing further CT scans in patients with suspected splenic injuries and not intervening in cases of a contrast extravasation were the most important discrepancies to the current literature. Standardization of the NOM of splenic injuries may be of great benefit for both surgeons and patients.     

Intra-abdominal infection following combined spleen-colon trauma

The reality of late overwhelming post-splenectomy sepsis in adults as well as children has led to more frequent attempts at splenic salvage following splenic trauma. Less attention has been paid to early septic postoperative complications in the splenectomized patient. Associated colon injury has been believed to be a relative contraindication to splenic conservation. If splenectomy enhances the chance of early postoperative infection, then associated colon injury should be an indication for splenic salvage One hundred sixty one patients who had either splenic trauma (58), colon trauma (90), or combined spleen-colon trauma (13) were studied. All patients with splenic trauma had a splenectomy. There was a significantly higher incidence of intra-abdominal sepsis requiring reoperation in the spleen-colon patients (46.7%) than in either of the other groups (spleen = 5.7%, colon = 8.9%, P less than .002 for both comparisons). It is concluded that splenectomy enhances infection in the early postoperative period. When possible, combined spleen-colon trauma should be an indication rather than a contraindication for splenic salvage.     

Serum antibody responses to pneumococcal vaccine after splenic autotransplantation

Immunization with pneumococcal capsular polysaccharide vaccines is advocated after splenectomy; however, experimental and clinical data suggest an impaired antibody response in splenectomized individuals. This study examined the value of splenic autotransplantation at various sites in augmenting the antibody response to Type III pneumococcal capsular polysaccharide in mice immunized 3 months after operation. Splenectomy resulted in impaired antibody responses compared to sham-operated mice (p less than 0.001) using an enzyme-linked immunosorbent assay. Mice with intraperitoneal splenic autotransplants, but not mice with subcutaneous or intramuscular transplants, had greater antibody responses compared to splenectomized mice (p less than 0.05). Antibody responses were elevated only in mice autotransplanted with 50% or more of the original splenic mass. Since autotransplantation of splenic tissue augments the antibody response to pneumococcal capsular polysaccharides, the combination of splenic autotransplantation and pneumococcal vaccination may confer more protection than either modality alone in individuals who must undergo splenectomy.     

Conservative management in blunt splenic trauma

We reviewed for analysis the charts of two groups of adults patients with blunt splenic injuries issued from two University Hospital Centers; the group 1 (G1) of 22 patients and the group 2 (G2) of 20 patients. The results of actually therapeutic procedures concerning blunt splenic injuries and subsequently the effectiveness of non operative treatment were evaluated. Splenectomy was performed in G1 for 11 patients, instead of 19 patients in G2 (p = 0.0003), whereas, the non surgical treatment was done in 9 patients and 1 patient, respectively (p = 0.02). The mean Splenic Injury Score (SIS) was 2,95 in G1 and 3.47 in G2 (p = 0.03). The spleen was preserved in G1 for 8 patients, instead 1 patient in G2 (p = 0.04). In G1, the non operative treatment was successfully accomplished in 66% of patients. It was obtained with lack of mortality, with a lower overall morbidity and a lower length of hospital stay than in splenectomized patients, but the latter group accounted higher values of Injury Severity Scores (p < 0.05). If proper selection criteria for non operative management are used, more than a third of patients with blunt splenic injury can be treated by splenic preservation at least as safely as splenectomized patients.     

Pneumococcal vaccination in patients with chronic renal disease and renal allograft recipients

Polyvalent pneumococcal vaccine was administered to 7 patients with chronic renal failure, 14 patients on chronic hemodialysis, 14 splenectomized and 11 nonsplenectomized renal allograft recipients, and 14 normal adults. Ninety-three percent of normal subjects had at least a twofold rise in serum antibody concentration after vaccination, with a geometric mean antibody concentration after vaccination greater than 200 ng N/ml. The response to vaccination in hemodialysis patients was similar to that in normal persons. Renal failure patients showed impaired antibody synthesis in response to the vaccine, with 43% achieving at least a twofold rise in antibody concentration. Allograft recipients had a lower antibody concentration before as well as after vaccination, and among splenectomized recipients the prevaccination antibody concentration was directly related to the interval between transplantation and antibody determination. But, 80% of allograft recipients achieved a twofold rise in antibody concentration after vaccination. The response to pneumococcal vaccine was quantitatively similar for splenectomized and nonsplenectomized allograft recipients.     

Incidence and function of residual splenic tissue following splenectomy for trauma in adults

A limited study of children requiring splenectomy for trauma suggested a 59% incidence of splenosis. We attempted to confirm these results in 40 adult patients with trauma. Residual splenic tissue, from either splenosis or accessory spleens, was seen in 26% of patients who underwent splenectomy for trauma and subsequent splenic scintigraphy. There was no significant difference in serum IgM levels between control patients and splenectomy patients with or without residual splenic tissue. There was also no difference in the percentage of pitted RBCs in splenectomized patients with or without residual splenic tissue. However, both groups of splenectomized patients had significantly higher numbers of pitted RBCs than did controls. These results indicate that the incidence of residual splenic tissue, though significant, is lower than previously reported, and that natural splenosis probably results in a small splenic mass incapable of restoring total splenic function.     

Complications of splenectomy

During the last three decades it has become clear that removal of the spleen, for any reason, is not a benign procedure. In both adults and children splenectomy places the patient at significantly higher risk of overwhelming infection, compared to the normal population. The risk of the post-splenectomy septic syndrome is lifelong and is not eliminated by the administration of polyvalent pneumococcal vaccine. Thus far, the reported rate of overwhelming sepsis in asplenic individuals has ranged from 2.5-13.5%. As more long-term follow-up data become available, it is likely that the true incidence will be 5-10%. In addition to this late complication, splenectomy increases the frequency of adverse events, including death, in the immediate postoperative period. Infections, particularly pulmonary and abdominal sepsis, constitute the majority of the complications. The mortality rate from postoperative sepsis is substantial. Atelectasis, pancreatitis/fistula, pulmonary embolism and bleeding at the operative site are also relatively common occurrences following splenic removal. These alarming statistics have spurred surgeons to change their attitudes concerning splenectomy for trauma, both accidental and iatrogenic. Nonoperative management of hemodynamically stable patients with isolated splenic injury and splenorrhaphy in patients requiring laparotomy are now firmly entrenched in the surgical armamentarium. Patients in whom splenectomy is necessary are given polyvalent pneumococcal vaccine and are instructed to seek early medical attention for febrile illnesses. Splenic autotransplantation and lifelong prophylactic antibiotic therapy have been used in some centers, but their clinical value remains to be proven.     

Reversal of anticoagulation in trauma: a North-American survey on clinical practices among trauma surgeons

BACKGROUND: Recent studies addressing reversal of anticoagulation in trauma have reported conflicting results. We hypothesized that current clinical practice is variable throughout North America. METHODS: We surveyed 100 trauma surgeons to obtain information regarding variability in current clinical practice. RESULTS: Seventy-five of 100 trauma surgeons surveyed responded, and the majority (98.7%) agreed that preinjury anticoagulation poses problems in trauma management that include bleeding, increased complications, and mortality. Nine participants (12.2%) had a protocol addressing reversal of anticoagulation in their institution. Most use fresh frozen plasma based on the type and location of injury, initial international normalized ratio (INR), and targeted INR value. Fresh frozen plasma was consistently used in patients with positive head computed tomographic scans, hemothorax, nonoperative solid organ injury management, pelvic and long bone fractures, and any operative intervention. Practice inconsistencies were found in patients with loss of consciousness and normal head computed tomographic scan, facial and rib fractures, and pulmonary contusion. Significant variability was found in the reversal INR target. One third of participants agreed that anticoagulation could be restarted 5 to 7 days after craniotomy; one sixth would do so within 72 hours and one third would wait 10 or more days. Most agreed that anticoagulation could be restarted 3 days after chest, abdominal, and orthopedic operations. Significant inconsistencies were also observed regarding when to restart anticoagulation in closed head injury patients treated nonoperatively. CONCLUSION: On the basis of the discrepancies observed in this survey, a clinical trial addressing specific injury location and patterns, INR thresholds, and type of strategy to achieve reversal is warranted, and most would agree to participate.     

Effects of tuftsin on postsplenectomy sepsis

Tuftsin is a tetrapeptide within the CH2 domain of the IgG immunoglobulin. Enzymatically cleaved from its parent globulin, it increases the phagocytic activity of macrophages, monocytes, and neutrophils by specific receptor mechanisms. In splenectomized hosts the circulating levels of tuftsin are reduced. Postsplenectomy sepsis is due to impaired clearance of intravascular bacteria; it has been postulated that tuftsin deficiency may contribute to this impairment. In this experiment splenectomized DBA/2 mice were subjected to pneumococcal sepsis. The groups of mice treated with tuftsin and those that received autotransplanted splenic tissue had significantly improved survival rates. We conclude that tuftsin deficiency plays a role in postsplenectomy sepsis and that treatment with synthetic tuftsin protects the splenectomized host against pneumococcal septic death.     

The Society of Thoracic Surgeons manpower survey for 1976: a summary.

The results of a 1977 survey regarding places and types of thoracic surgical procedures performed in the United States are analyzed. Responses gathered from 2,240 thoracic surgeons showed that active thoracic surgeons between 34 and 54 years old performed 195,850 major thoracic or cardiac operations per year. Fifty-four percent of active surgeons responding were in solo practice, 40% practiced in groups of 2 to 5 surgeons, and the reamining 6% were in groups of 6 or more. Community size, regional distribution of services, proportion of professional activities allocated to various procedures, and estimates of additional capacity are also summarized.     

Adoption of direct discharge of simple stable injuries amongst (orthopaedic) trauma surgeons

IntroductionThe importance of routine follow-up of several relatively simple stable injuries (SSIs) is questionable. Multiple studies show that direct discharge (DD) of patients with SSIs from the Emergency Department results in patient outcomes and experiences comparable to ‘standard care’ with outpatient follow-up. The purpose of this study was to evaluate to which extent DD of SSIs has been adopted amongst trauma and orthopedic surgeons internationally, and to assess the variation in the management of these common injuries.MethodsAn online survey was sent to members of an international trauma- and orthopaedic surgery collaboration. Participants, all trauma- or orthopaedic surgeons, were presented with eleven hypothetical cases of patients with simple stable injuries in which they were asked to outline their treatment plan regarding number of follow-up appointments and radiographs, physiotherapy and when to start functional movement. The primary outcome was the proportion of surgeons selecting direct discharge (i.e. zero scheduled appointments), per injury. Secondary outcomes included clinical agreement (>80% of respondents answering similarly) on total number of follow-up appointments (0, 1 or ≥2), radiographs (0, 1 or ≥2), routine physiotherapy referral (yes/no) and when to start functional movement (weeks).Results138 of 667 (20.7%) surgeons completed the survey. Adoption of direct discharge ranged from 4-45% of case examples. In 10 out of 11 cases, less than 25% of surgeons selected direct discharge. Clinical agreement regarding number of appointments and when to start functional movement was not reached for any of the injuries. There was clinical agreement on number of radiographs for one injury and for four injuries regarding routine referral to a physiotherapist.DiscussionDespite available evidence, DD of SSIs has not been widely adopted worldwide. Practice variation still exists even for these common injuries. This variation suggests inefficiency and consequently unnecessarily high healthcare costs. (Orthopaedic) trauma surgeons are encouraged to evaluate their current treatment protocols of SSIs.     

Reimmunization and splenic autotransplantation: A long-term study of immunologic response and survival following pneumococcal challenge

Splenic autografts have phagocytic function and increase survival after experimental sepsis. The long-term effect of transplant viability, phagocytic capacity, and immunologic responsiveness were evaluated. Rats were divided into experimental groups: control, splenectomized, and splenic autotransplant rats. Approximately one-half of the rats were immunized against pneumococcus. Twelve months later, the rats were reimmunized, and the pneumococcal antibody titers were measured. The effect of operation and immunization was determined by challenging rats with intravenously administered pneumococci. Bacterial clearance from the bloodstream was measured and mortality recorded. Spleens were weighed and examined histologically. In unimmunized rats, pneumococcus was cleared from the bloodstream of control rats, whereas splenectomized and splenic autotransplant rats demonstrated a progressive increase of pneumococci in the bloodstream. However, splenic autotransplant rats grew fewer bacteria after challenge (P < 0.05). All control rats survived. Thirty-three percent of splenic autotransplant rats were alive, but significantly fewer splenectomized rats (6%) survived (P < 0.05). After reimmunization, highest antibody titers were noted in control rats (P < 0.05). Splenic autotransplant rats had higher antibody titers than did splenectomized rats (P < 0.05). Reimmunized splenic autotransplant rats had greater survivorship (71%) when compared with reimmunized splenectomized rats (26%) (P < 0.003). At 1 year, transplants were smaller than control spleens (P < 0.001), although histologic integrity was maintained. Splenic autotransplantation results in better phagocytic function, improved response to reimmunization, and increased survival after pneumococcal challenge and may be an important measure in preventing postsplenectomy sepsis.