Low incidence of serum neutralizing factors in patients receiving recombinant alfa-2b interferon (Intron A).

The development of serum neutralizing factors against recombinant alfa-2b interferon (Intron A) was reviewed in a large clinical experience. In 537 patients receiving systemic therapy, neutralizing factors developed in only 13 (2.4 percent). In 1,326 patients who received intranasal administration and 154 with intralesional administration, the incidence was less than 1 percent. Patients in whom antibody developed had no predisposing characteristics that could be identified, no particular types of patients with cancer had a high rate of neutralizing factors, and two of 10 patients with cancer in whom neutralizing factor developed were still able to show clinical responses. In patients in whom neutralizing factor was present, there was no discernible difference in the incidence or severity of interferon side effects as compared with patients who had no demonstrable neutralizing factor levels. This form of recombinant alpha-2 interferon appears to have a very low antigenic potential.

Radioimmunoassay and opsonic antibody responses to pneumococcal capsular polysaccharide vaccine in serum and ascitic fluid of cirrhotic patients.

Pneumococcal capsular polysaccharide vaccine was administered to 19 cirrhotic patients and to 25 control subjects. Radioimmunoassay antibody concentration and opsonic titers (OT) were measured in sera and ascites collected before and 3 to 4 weeks after inoculation. The geometric mean antibody concentrations in prevaccination sera from the cirrhotic patients were significantly increased to types 3, 4, 7F, 8, 9N, and 12F antigens, and in postinoculation sera their geometric mean antibody concentration was increased to types 3, 9N, and 12F antigens. OT to Streptococcus pneumoniae type 3 correlated with the radioimmunoassay antibody concentration in postinoculation sera. Of 14 cirrhotic subjects, 3 had OT of greater than or equal to 4 in prevaccination sera, and the highest OT and radioimmunoassay antibody concentration were observed in postinoculation specimens from this group. Antibody and OT against S. pneumoniae type 3 were also observed in ascitic specimens. These data suggest that cirrhotic subjects respond to pneumococcal capsular polysaccharide with antibodies in both serum and ascitic fluid. However, the protective efficacy of this antibody response must be assessed by larger prospective studies.

Pneumococcal capsular polysaccharide vaccination in adult chronic hemodialysis patients.

PCP vaccine was administered to 21 adult hemodialysis patients and 25 control patients with no renal nor hepatic dysfunction. Antibody concentrations measured by the RIA technique were lower in the hemodialysis than in the control patients in both prevaccination sera and specimens obtained 3 to 4 weeks following vaccination. However, 6 months after vaccination, RIA GMACs in hemodialysis and control subjects were more nearly alike. OTs against Streptococcus pneumoniae, types 1 and 3, were measured in paired sera from vaccine recipients. Opsonic activity against S. pneumoniae, type I, was detected as frequently in the 3 to 4 week postvaccine sera of the dialysis as in those of control patients. However, there was a poor correlation between OTs and RIA-ACs against this organism. There was good correlation between OT and RIA-AC against type 3 pneumococci in 3 to 4 week postvaccine sera, and significantly more control patients had opsonic activity detectable in these specimens. No clinical S. pneumoniae infections have been observed in vaccine recipients. However, continued follow-up will be necessary to document the degree to which hemodialysis patients are protected by pneumococcal vaccines and the relationship between protection and antibody concentration or OTs.