Wound Botulism Associated with Black Tar Heroin

The incidence of wound botulism is increasing and the epidemiology of the disease is changing. The majority of new cases are associated with injection drug use, in particular, the use of Mexican black tar heroin. This case report and discussion of wound botulism illustrate the following important points: Dysphagia, dysphonia, diplopia, and descending paralysis, in association with injection drug use, should alert the treating physician to the possibility of wound botulism. In such patients, the onset of respiratory failure may be sudden and without clinically obvious signs of respiratory weakness. For the reported patient, maximum inspiratory force measurements were the only reliable indicator of respiratory muscle weakness. This is a measurement not routinely performed in the ED, but may prove essential for patients with suspected wound botulism. To minimize the effect of the botulinum toxin and to decrease length of hospital stay, antitoxin administration and surgical wound debridement should be performed early.     

A defective Vkappa A2 allele in Navajos which may play a role in increased susceptibility to haemophilus influenzae type b disease.

The antibody response to H. influenzae type b (Hib) is pauciclonal, and is dominated by antibodies using the VkappaA2 gene. Navajos have a 5-10-fold increased incidence of Hib disease compared with control populations. We hypothesized that a polymorphism in one of the genes in this oligoclonal response may lead to increased disease susceptibility. Since the predominant A2+ anti-Hib antibodies have high avidity for Hib and can be unmutated, the A2 Vkappa gene was analyzed. Over half of the Navajos studied, but only one control individual, had a new allele of A2, termed A2b, with three changes from the published A2 germline sequence. One of the changes was in the recombination signal sequence, suggesting that the A2b allele might not undergo V-J rearrangement very frequently. This possibility was confirmed by analyzing the relative frequency of non-productive A2 rearrangements in A2a/b heterozygous Navajos. Many fewer A2b rearrangements were observed, showing that the A2b allele is defective in its ability to undergo rearrangement. The prevalence of this allele in Navajos may play a role in their increased susceptibility to invasive Hib disease. If so, it would underscore the importance of the germline Ig repertoire for protective antibody responses to pathogenic bacteria in unimmunized children.