IVIg is a gamma globulin made from purified pooled plasma of thousands of donors, consisting mainly of IgG, and sourced from outside the United Kingdom due to the risk of Creutzfeldt-Jakob disease.[
6] IVIg is thought to work by a variety of mechanisms including antibody protection against lipopolysaccharides, neutralizing superantigens, modulation of Fc-receptor blockade and expression, inhibition of membrane attack complexes (C5b-9), and complement activation and also by facilitating the opsonization of GAS bacteria. This concept of immunomodulation of the inflammatory cascade may apply during sepsis, with use of IVIg in GAS.[
6,
7]
A multicenter, double-blind RCT examining the use of high dose IVIG as adjunctive therapy in STSS, in addition to clindamycin and penicillin, was published in 2003.[
7] Placebo control was with 1% albumin, with the primary end point being effect on 28-day mortality with use of IVIg (1 g/kg on day 1, then 0.5 g/kg on days 2 and 3). This is the protocol currently used in our unit. Power calculation was for 120 patients, and only 21 were randomized due to recruitment difficulties. An insignificant trend toward lower mortality (10% vs. 36%), as well as a significant decrease in sepsis-related SOFA scores at days 2 (
P=0.02) and 3 (
P=0.04), was observed in the IVIg group. Further evidence is provided from a Canadian observational study comparing 21 consecutive patients who were given IVIg for STSS.[
8] Although there was no difference in duration of ventilation or hospital stay (LOS), survival to 30 days was improved in the IVIg group (67% vs. 34%,
P=0.02). In contrast a recent paper examining the use of IVIg in 84/192 pediatric STSS patients found no significant mortality reduction and longer LOS and higher hospital costs.[
9] Current UK Department of Health guidelines for use of IVIg in infectious diseases [] recommends that “IVIg may be added to adequate toxin-neutralising antimicrobials, source control and sepsis management when these approaches have failed to elicit a response.”[
10]
| Table 1United Kingdom department of health guidelines for immunoglobulin use in infectious diseases[5] |
This patient had severe septic shock where use of IVIg has also been reported. Turgeon
et al.[
11] looked at RCTs comparing IVIg with placebo (or no intervention) in critically ill adult patients with sepsis, and found a 26% survival benefit associated with use of polyclonal IVIg (RR 0.74 [95% CI, 0.62--0.89]:
P=0.001 with a number of patients needed to treat to save one life (NNT) of 9. A meta-analysis by Laupland
et al.[
12] found overall significant reduction in mortality with IVIG treatment (OR 0.66 (95% CI, 0.53--0.83;
P<0.0005), although this result was not confirmed when only high-quality studies were analyzed. Kreyman
et al.[
13] looked at 27 RCTs, 15 of which involved 1492 adults and children with trials of polyclonal IVIG in septic patients. Again reduced mortality was demonstrated, with adult data showing RR 0.79 (95% CI, 0.69--0.90). Among the authors’ conclusions in these trials was that, “an adequately powered RCT was needed to confirm the effects of IVIG in septic shock,” on the background of previous trials having methodological flaws and heterogeneous data. In 2007 the placebo-controlled RCT SBITS was published, which examined the use of IVIg in patients with sepsis.[
14] Twenty-eight-day mortality was not reduced significantly, 37.3% versus 39.3% in the IVIg group (
P=0.6695), and there was also no improvement in 7-day mortality or pulmonary function. One point of note was that this trial used a smaller total dose of IVIg (0.9 mg/kg), than the multicenter trial using IVIg in STSS.[
7]
A Cochrane review update,[
15] which found 17 trials in adults (
n=1958), concluded that polyclonal IVIg had a mortality benefit in adults (RR 0.77, 95% CI 0.68--0.87); however this was not reproduced when examining trials with low risk of bias. Current DoH guidance,[
10] and recent drugs and therapeutics bulletin advice, do not recommend the use of IVIg in general sepsis.
IVIG cost is climbing and well over $50/g. ($10,000 for a 100 kg (220 lbs) person at 2 g/kg), this will necessitate careful appraisal of its cost benefit by each treating institution. Neilson
et al.[
16] showed, on the basis of a meta-analysis of studies undertaken in adult septic patients, that the addition of IgM-enriched IVIG to standard therapy has a positive association with reduced mortality. The increased cost equated to €5715-€28443/life saved which compares favorably with other recommendations for adjuvant therapies in sepsis. For example, the addition of APC had a cost implication of €100728-€120176/life saved. A further meta-analysis[
11] demonstrated favorable comparisons with other current recommendations in sepsis, in relation to NNT and on an economic basis, e.g., IVIg in adults; NNT 9, RR (95% CI): 0.74 (0.62--0.89) compared to APC; NNT 16, RR (95% CI): 0.80 (0.69--0.94).[
11,
17]
There are no recommendations for the use of IVIg in the current surviving sepsis guidelines for adults, though it may be considered it pediatric septic shock.[
18] The omission of IVIg from these adult guidelines was recently reviewed,[
19] with the conclusion being that small trials of low quality formed the basis of positive results. In addition the largest RCT (SBITS trial described above)[
14] failed to demonstrate benefit, with standard IgG IVIg in adult septic patients. However the potential benefit of IgM-enriched IVIg preparations has been shown in experimental sepsis models and meta-analyses,[
11,
13] with Kreyman
et al.[
13] raising the possibility of “significant benefit of IgM-enriched IVIg in adult and neonatal sepsis.” It is likely that further larger controlled RCT's concerning IgM-enriched IVIg in adult sepsis will be needed prior to concrete recommendations in international sepsis guidelines.